ADDRESSING EMERGING INFECTIOUS DISEASE THREATS:  A PREVENTION STRATEGY FOR 
THE UNITED STATES




Centers for Disease Control 
and Prevention                           David Satcher, M.D., Ph.D., Director
                                     Walter R. Dowdle, Ph.D., Deputy Director

This report was prepared and produced by the
     National Center for 
     Infectious Diseases (NCID)               James M. Hughes, M.D., Director
                                     Ruth L. Berkelman, M.D., Deputy Director
                                
Emerging Infections Working Group           Ralph T. Bryan, M.D., Division of 
                                         Parasitic Diseases, and Coordinator, 
                                                  Emerging Infections Project
                                Robert W. Pinner, M.D., Division of Bacterial
                                                         and Mycotic Diseases
                          Robert P. Gaynes, M.D., Hospital Infections Program
                        C. J. Peters, M.D., Division of Viral and Rickettsial
                                                                     Diseases
                            Meredith A. Hickson, M.P.H., Division of HIV/AIDS
                         Judith R. Aguilar, Division of Viral and Rickettsial 
                                                                     Diseases

          Office of Program Resources   Meredith A. Hickson, M.P.H., Director

               Publications Activity             Polyxeni Potter, M.A., Chief
                                                              Beverly Holland
                                                              Sharon Hoskins
                                                              
Information Resources Management Activity            Cheryl G. Shapiro, Chief
                    Cover Design                            Patricia A. Tyson
                                                           Kevin E. Jefferson
 
  
 in consultation with
     Epidemiology Program Office Barbara R. Holloway, M.P.H., Acting Director
 

     International Health Program Office Joe H. Davis, M.D., M.P.H., Director
 

     National Center for Chronic Disease 
     Prevention and Health Promotion                 James S. Marks, Director

     National Center for 
     Environmental Health    Stephen B. Thacker, M.D., M.Sc., Acting Director
 

     National Center for 
     Health Statistics              Manning Feinleib, M.D., Dr.P.H., Director

     National Center for 
     Injury Prevention and Control  Mark L. Rosenberg, M.D., M.P.P., Director

     National Center for 
     Prevention Services               Alan R. Hinman, M.D., M.P.H., Director

     National Immunization Program        Walter A. Orenstein, M.D., Director

     National Institute for 
     Occupational Safety and Health  Richard A. Lemen, Ph.D., Acting Director

     Public Health Practice 
     Program Office                   Edward L. Baker, M.D., M.P.H., Director

_____

Table of Contents

	Preface
	Executive Summary
	Background
	The CDC Prevention Strategy
	The Critical Role of Partnership
	Implementation
	Acknowledgements
	References
	Summary of Figures, Tables, and Boxes

---

Preface

The spectrum of infectious disease is changing rapidly in conjunction with 
dramatic changes in our society and environment. Worldwide, there is 
explosive population growth with expanding poverty and urban migration; 
international travel is increasing; and technology is rapidly changing all of
which affect our risk of exposure to the infectious agents with which we 
share our environment. Despite historical predictions to the contrary, we 
remain vulnerable to a wide array of new and resurgent infectious diseases.

The President's Health Security Act of 1993 addresses the need for universal
health care coverage as well as the need to enhance community-based public 
health strategies. As our nation proceeds with health care reform, we must 
identify those public health priorities that need to be addressed at the 
community level as well as those that can be addressed by individual patient
care providers. Preventing infectious diseases must be a high priority in a 
reformed health care system and requires close cooperation between 
clinicians and public health professionals.

Our vulnerability to emerging infections was dramatically demonstrated in 
1993. A once obscure intestinal parasite, Cryptosporidium, caused the 
largest waterborne disease outbreak ever recognized in this country; an 
emerging bacterial pathogen, Escherichia coli O157:H7, caused a multi-state 
foodborne outbreak of severe bloody diarrhea and kidney failure; and a 
previously unknown hantavirus, producing an often fatal lung infection, was
linked to exposure to infected rodents.

In recent years, our antimicrobial drugs have become less effective against 
many infectious agents, and experts in infectious diseases are concerned 
about the possibility of a "post-antibiotic era". At the same time, our 
ability to detect, contain, and prevent emerging infectious diseases is in 
jeopardy.

Since 1987, the National Academy of Science's Institute of Medicine has 
published three reports, each of which documents, from different 
perspectives, the urgent need to improve our ability to identify infectious 
disease threats and respond to them effectively. To meet this urgent need, 
we must improve the public health infrastructure at the local, state, and 
federal levels and recognize that the health of the American people is 
inextricably linked to the health of people in other nations; infectious 
diseases can and do spread rapidly around the globe; and global surveillance 
for emerging infections is vital to public health.

In partnership with local and state public health officials, other federal 
agencies, medical and public health professional associations, infectious 
disease experts from academia and clinical practice, and international and 
public service organizations, the Centers for Disease Control and Prevention
(CDC) has developed a plan that addresses the priorities set forth in the 
three Institute of Medicine reports and Healthy People 2000 and serves as a 
guide for CDC to work in collaboration with its partners in safeguarding 
this nation from the threat of emerging infectious diseases.

Development of this plan began in December 1992 at a meeting of the Board of
Scientific Counselors of CDC's National Center for Infectious Diseases. 
Guidance was subsequently obtained at a meeting of infectious disease and 
public health experts in Atlanta in March 1993 and at a meeting of state and
territorial public health epidemiologists, laboratory directors, and 
veterinarians in Minneapolis in June 1993. Drafts of this plan have also 
been reviewed by leaders of numerous medical, scientific, and public health 
organizations. The assistance obtained throughout this process has been 
invaluable in ensuring that the plan reflects the public health concerns of 
a large number of medical and public health experts.

Plan implementation will require long-term collaborations and partnerships 
with clinicians, microbiologists, public agencies, universities, private 
industry, and communities. As the Nation's Prevention Agency, CDC looks 
forward to working with its many partners to address the challenges of 
emerging infectious disease threats.


David Satcher, M.D., Ph.D.
Director
Centers for Disease Control and Prevention

---

Executive Summary


 "Ingenuity, knowledge, and organization alter but cannot cancel humanity's 
vulnerability to invasion by parasitic forms of life. Infectious disease 
which antedated the emergence of humankind will last as long as  humanity 
itself, and will surely remain, as it has been hitherto,  one of the 
fundamental parameters and  determinants of human history." 

William H. McNeill in Plagues and Peoples, 1976
 
Once expected to be eliminated as a public health problem, infectious 
diseases remain the leading cause of death worldwide. Dramatic changes in 
society, technology, and the environment together with the diminished 
effectiveness of certain approaches to disease control have propelled this 
nation and the rest of the world into a new era; the spectrum of infectious 
diseases is expanding and many infectious diseases once thought conquered 
are increasing.

To effectively address emerging infectious diseases, the Centers for Disease
Control and Prevention (CDC) has developed a strategic plan emphasizing 
surveillance, applied research, and prevention activities critical to 
maintaining a strong defense against infectious diseases that affect, or 
threaten to affect, the public's health. The goals of this plan are as 
follows:


Goal I
 

Surveillance: Detect, promptly   investigate, and monitor emerging   
pathogens, the diseases they cause,   and the factors influencing their   
emergence.


Goal II 


Applied Research: Integrate   laboratory science and epidemiology   to 
optimize public health practice.


Goal III 


Prevention and Control: Enhance  communication of public health   
information about emerging diseases   and ensure prompt implementation of   
prevention strategies.


Goal IV 


Infrastructure: Strengthen local, state,  and federal public health 
infrastructures   to support surveillance and implement   prevention and 
control programs.


Both individual health care coverage and core public health functions are 
needed to maintain health at the community level. Implementation of this 
plan will be a critical step toward ensuring health security for all 
Americans.

The Concept of Emergence

Emerging infectious diseases are diseases of infectious origin whose 
incidence in humans has increased within the past two decades or threatens 
to increase in the near future (1).

Many factors, or combinations of factors, can contribute to disease 
emergence. Newly emergent infectious diseases may result from changes or 
evolution of existing organisms; known diseases may spread to new geographic
areas or new human populations; or previously unrecognized infections may 
appear in persons living or working in areas undergoing ecologic changes, 
such as deforestation or reforestation, that increase their exposure to 
insects, animals, or environmental sources that may harbor new or unusual 
infectious agents (2-5).

Reemergence of infectious diseases may occur because of the development of 
antimicrobial resistance in existing agents (e.g., gonorrhea, malaria, 
pneumococcal disease) or breakdowns in public health measures for previously
controlled infections (e.g., cholera, tuberculosis [TB], pertussis).

The Threat of Emerging Infections

In the United States and elsewhere, infectious diseases increasingly 
threaten public health and contribute significantly to the escalating costs
 of health care. As society, technology, and the environment change, 
pathogens evolve or spread, and the spectrum of infectious diseases expands.

Emerging infections, such as acquired immunodeficiency syndrome (AIDS) and 
TB, vividly illustrate that no nation can be complacent regarding human 
vulnerability to the microorganisms with which we share our environment. 
Since the early 1970s, the U.S. public health system has been challenged 
by many newly identified pathogens and syndromes, such as Lyme disease, 
Legionnaires' disease, toxic shock syndrome, human immunodeficiency 
virus/AIDS, hepatitis C virus, cryptosporidiosis, and, most recently, 
hantavirus.

In addition, the incidence of many diseases widely presumed to be under 
control such as cholera, dengue, yellow fever (YF), and TB has increased in 
many areas or spread to new regions or populations throughout the world. As 
a consequence of widespread use and misuse of antimicrobial drugs, this 
country also faces the emergence of drug-resistant pathogens. Even drugs 
used in the treatment of common bacterial infections are becoming 
increasingly ineffective, resulting in prolonged illnesses, higher mortality
rates, and higher health care costs.

Emerging infections are particularly serious in persons with lowered 
immunity, such as those infected with HIV and those receiving medications 
for cancer or organ transplantation, whose numbers are increasing. Others 
who may be disproportionately affected by emerging infections include the 
elderly; persons living in institutional settings, such as hospitals and 
nursing homes; and those with inadequate access to health care, such as the 
homeless, migrant farm workers, and others of low socioeconomic status.

The number of children attending child care facilities has increased 
dramatically in the past decade as mothers of young children have 
increasingly entered the work force. These children, now numbering over 11 
million, are at a markedly increased risk for enteric infections, such as 
hepatitis A, giardiasis, and cryptosporidiosis; respiratory illnesses; and 
middle ear infections. Additionally, many of these illnesses are carried 
home and transmitted to other members of a household.

 Examples of Emerging Infectious Diseases, United States, 1993
 

E. coli O157:H7 disease
Cryptosporidiosis
Coccidioidomycosis
Multidrug-resistant pneumococcal disease
Vancomycin-resistant enterococcal infections
Influenza A/Beijing/32/92
Hantavirus infections


Examples of Emerging Infectious Diseases, Outside the United States, 1993
 

Cholera in Latin America
Yellow Fever in Kenya
Vibrio cholerae O139 in Asia
E. coli O157:H7 in South Africa and Swaziland
Rift Valley Fever in Egypt
Multidrug-resistant Shigella dysenteriae in Burundi
Dengue in Costa Rica
Diphtheria in Russia


Emerging infections transmitted by contaminated foods and public water 
supplies place entire communities at risk. Early in 1993, hamburgers 
contaminated with the bacterial pathogen Escherichia coli O157:H7 and served
 at a fast-food restaurant chain caused a multi-state outbreak of 
hemorrhagic colitis (bloody diarrhea) and serious kidney disease, resulting 
in the deaths of at least four children. In the spring of 1993, 
contamination of a municipal water supply with the intestinal parasite 
Cryptosporidium caused the largest recognized outbreak of waterborne illness
 in the history of the United States; an estimated 403,000 persons in 
Milwaukee, Wisconsin, had prolonged diarrhea, and approximately 4,400 
persons required hospitalization.

Lack of surveillance and limited availability of appropriate diagnostic 
tests interfere with public health efforts to prevent and control outbreaks.
Both E. coli O157:H7 and Cryptosporidium were first recognized as 
significant human pathogens in the early l980s, but neither has received 
adequate public health attention.

Exposure to certain animals is also placing Americans at risk for emerging 
infectious diseases. Hantavirus pulmonary syndrome (HPS), first detected in 
the southwestern United States in 1993, has been linked to exposure to 
infected rodents in over a dozen states. More than 50 cases have been 
detected and more than half of those infected have died.

Once considered "exotic", tropical infectious diseases are having an 
increasing effect on the American public. Although the true impact is 
unknown, several recent examples include severe illness and at least one 
death due to cholera among international airline passengers arriving in 
California; malaria in residents of southern California and immigrants in 
North Carolina; fever and heart failure in New York and Canada among 
patients who received blood transfusions contaminated with the bloodborne 
parasite that causes Chagas disease in Latin America; and a newly 
described form of the parasitic blood and bone marrow infection, 
leishmaniasis, in troops returning from the Persian Gulf conflict.

From a historical perspective, cholera, smallpox, and plague are examples of
infectious diseases that spread globally with devastating impact, often 
occurring during periods of rapid economic change or population growth.5 In 
modern times, travel and commerce have fostered the worldwide spread of 
HIV/AIDS and influenza as well as the reemergence of cholera as a global 
health threat. As Nobel Laureate Dr. Joshua Lederberg has stated, "The 
microbe that felled one child in a distant continent yesterday can reach 
yours today and seed a global pandemic tomorrow". Clearly, emerging 
infections can affect people everywhere, regardless of lifestyle, cultural 
or ethnic background, or socioeconomic status.

The public health infrastructure of this country is poorly prepared for the 
emerging disease problems of a rapidly changing world. Current systems that 
monitor infectious diseases domestically and internationally are inadequate 
to confront the present and future challenges of emerging infections. Many 
foodborne and waterborne disease outbreaks go unrecognized or are detected 
late; the magnitude of the problem of antimicrobial drug resistance is 
unknown; and global surveillance is fragmentary.

Surveillance of infectious diseases in the United States is heavily 
dependent upon voluntary collaboration between CDC and state and local 
health departments, which in turn depend on physician- initiated reporting 
of a limited number of specific, recognized infectious diseases. Reporting 
is generally incomplete.

Results from a recent survey by the Council of State and Territorial 
Epidemiologists illustrate the inadequacy of existing infectious disease 
surveillance by documenting the limited number of professional positions 
dedicated to infectious disease surveillance in most states. For example, 
in 12 of the 50 states surveyed, no professional position is dedicated to 
surveillance of foodborne and waterborne diseases. Funding for communicable 
disease surveillance is largely confined to diseases for which public health
crises have already developed; over 95% of funds allocated to states for 
infectious disease surveillance are targeted to four disease categories 
(TB, HIV/AIDS, sexually transmitted diseases, and selected vaccine-
preventable diseases)6.  No federal resources are provided to state and local
health departments to support the national notifiable disease system. 
Likewise, the ability of state public health laboratories to support the 
surveillance, diagnosis, and control of infectious diseases has diminished.

Timely recognition of emerging infections requires early warning systems to 
detect these diseases, so that they can be quickly investigated and 
controlled before they become major public health crises. Prompt detection 
of these new threats requires careful monitoring by effective surveillance 
systems, a thorough understanding of trends in incidence and distribution of 
known infectious agents, and good communication among clinicians, medical 
laboratories, and public health systems.

The ability to detect what is new or reemerging depends on the capacity to 
identify and track the routine as well as the unusual. Like radar or "early 
warning" systems that detect threats to national security, surveillance with 
appropriate laboratory support is critical to an effective defense against 
these diseases. They are the most important tools for determining which 
infectious diseases are emerging, causing serious public health problems, or
receding.

Effective surveillance also provides a basis for evaluating the outcome of 
both public health and personal medical care programs. Surveillance 
information can ensure the use of the most efficacious and cost- effective 
approaches to preventive, as well as curative, health care. Whatever shape 
health care reform takes in this country, surveillance will be key to the 
meaningful evaluation of new programs.

In addition to comprehensive and innovative surveillance systems, effective 
preparation for emerging infectious diseases requires sound foundations in 
professional expertise, laboratory support, and research capability. These 
foundations support the infrastructure needed to address the ongoing, but of
ten changing, threats from emerging infections. Despite the continued 
emergence of such threats, support for applied research and control efforts 
has declined over the past decade for most infectious diseases.

As highlighted in three recent reports by expert committees convened by the 
National Academy of Science's Institute of Medicine (IOM), the ability of 
the U.S. public health system and our health professionals to deal with 
emerging infectious disease problems is in jeopardy.1,7,8  The earliest of these 
reports, "The U.S. Capacity to Address Tropical Infectious Disease Problems",7 
published in 1987, documented our poor state of readiness to recognize, 
treat, or control infectious disease threats emanating from the 
tropicsregions which have yielded such microbial threats as Lassa fever and 
Ebola viruses, chloroquine-resistant malaria, and penicillin-resistant 
gonorrhea. The second IOM report, The Future of Public Health, published in 
1988, concluded that the U.S. public health system is in disarray. It 
emphasized that U.S. approach to public health has too often been crisis 
driven, an approach that is costly because it blocks our ability to 
institute cost-saving preventive strategies.8

The third IOM report, "Emerging Infections, Microbial Threats to Health in 
the United States", published in 1992, emphasized the ongoing threat to 
domestic and global health from emerging infectious diseases.1  The report 
provided specific recommendations for CDC, the National Institutes of Health,
the Food and Drug Administration, the Department of Defense, and other state
and federal agencies for addressing microbial threats to health in the 
United States and elsewhere. This report emphasized a critical leadership 
role for CDC in a national and global effort to detect and control 
emerging infectious disease threats.

The CDC Prevention Strategy

To effectively detect and prevent emerging infections, significant 
improvements are needed in public health systems, program design, and 
infrastructure. Toward this end and the achievement of the objectives of 
Healthy People 2000, CDC has developed a strategy to address these microbial
threats. Because meeting the broad challenge of emerging infections requires
interaction, cooperation, and coordination among a wide range of public and 
private organizations, the development of this strategy has taken place in 
partnership with state and local health departments, other federal agencies,
academic institutions, international organizations, health care providers, 
medical laboratory personnel, and others.

CDC's plan, "A Prevention Strategy for the United States", contains four 
critical goals that address, in a broader context, specific IOM 
recommendations for revitalizing our nation's ability to identify, contain, 
and most importantly, prevent illness from emerging infectious diseases 
(Table, page 6).


Goal I (Surveillance) emphasizes the improvement and expansion of infectious
disease surveillance in the United States and internationally. Included 
under this goal are plans for strengthening local and state public health 
programs for infectious disease surveillance, establishing provider-based 
Sentinel Surveillance Networks, and creating population-based Emerging 
Infections Epidemiology and Prevention Centers at various sites across the 
United States. Also included are plans for a global consortium of closely 
linked epidemiology/biomedical research centers to promote the detection, 
monitoring, and investigation of emerging infections. Other objectives 
emphasize improved detection and monitoring of trends of antimicrobial 
resistance in institutional as well as community settings; expansion of 
field investigations and epidemic response capabilities; detection and 
prevention of foodborne and waterborne infections; and improved knowledge 
of the distribution of animal reservoirs and vectors associated with human 
infectious diseases.


Goal II (Applied Research) focuses on applied research and the integration 
of laboratory science and epidemiology with public health practice. Emphasis
is placed on determining how behavioral factors influence the emergence or 
prevention of new infections; better characterizing the public health and 
economic impact of both well-established and emerging infections; and 
evaluating the effectiveness and economic benefit of strategies to prevent 
emerging infectious diseases. An additional focus is the development and 
application of improved laboratory techniques for identifying new pathogens 
and the expanded use of molecular epidemiology in investigating emerging 
diseases. Priorities also include improving rapid response capability and 
contingency plans for the emergence of new strains of known pathogens, and 
conducting vaccine efficacy studies to support the President's Childhood 
Immunization Initiative. An additional priority is the reestablishment of 
CDC extramural programs to promote effective partnerships with public 
agencies, universities, and private industry and to support research in 
surveillance, epidemiology, and prevention of emerging infections.


Goal III (Prevention and Control) addresses enhanced communication of 
public health information and the implementation of prevention strategies 
for emerging infections. Highlighted under this goal are plans for expanded 
dissemination of CDC's Morbidity and Mortality Weekly Report), as well as 
other important public health information sources. Another priority is the 
creation of an accessible and comprehensive U.S. infectious disease database
that increases awareness of infectious diseases and promotes public health 
action. The database will contain information on such topics as 
antimicrobial resistance, foodborne and waterborne disease outbreaks, 
travelers' health, antimicrobial drug availability, vaccine preventable 
diseases, and vaccine guidelines. Other activities address the development 
and implementation of guidelines for preventing emerging infectious diseases
and the provision of prevention information.


Goal IV (Infrastructure) deals with issues relating to local, state, and 
federal infrastructures, particularly personnel and physical resources. 
Points of emphasis include maintaining expertise in rare or unusual 
infectious diseases, and establishing training programs that emphasize the 
diagnosis of infectious diseases. A public health laboratory fellowship in 
infectious diseases is proposed. Also emphasized is the need for state-of-
the-art physical resources laboratory space, training facilities, and 
equipment. Laboratory capabilities must be maintained in a manner that 
optimizes flexibility and "surge capacity", so that unanticipated public 
health threats can be adequately, efficiently, and safely addressed. Also 
proposed are plans for expanding facilities for maintaining specimen banks 
of etiologic agents and clinical specimens.

This plan reflects CDC's commitment to meet the challenge of important 
emerging public health problems. The need to proceed rapidly is made more 
urgent by a number of diseases that pose an immediate danger: methicillin-
resistant Staphylococcus aureus, a common cause of hospital infections, may
be developing resistance to vancomycin; penicillin resistance is spreading 
in Streptococcus pneumoniae; cholera will likely be introduced into the 
Caribbean islands from the current pandemic in Latin America, and the new 
strain, Vibrio cholerae O139, is spreading throughout southern Asia; 
changing food industry practices, dietary choices of the American people, 
and globalization of food supplies will bring new challenges to providing a 
diet safe from pathogens such as Salmonella sp. and E. coli O157:H7; and 
ongoing investigations of HPS document that the geographic distribution of 
this infection is much broader than the desert Southwest. These infectious 
disease problems demonstrate the urgency for expeditiously implementing this
plan.

The goals and activities in this plan are consistent with the goals set 
forth in recently proposed plans for health care reform. Examples of issues 
in infectious disease emergence that are particularly relevant to these 
plans include prolonged hospitalizations caused by hospital-acquired 
infections; increased morbidity and treatment costs resulting from 
antimicrobial resistance; and excessive burdens placed on public and private
health care facilities due to community-wide outbreaks of foodborne and 
waterborne infections.

Some of the activities listed in this document are already in the planning 
stages and will be implemented soon. Most will require additional funds and 
personnel. Specific details of many of the proposed activities need further 
development in full cooperation with other federal agencies, state and local
health authorities, academic institutions, professional societies, private 
industry, and others. With this document as a guide and a first step, 
implementation will be based on public health needs and resource 
availability. This process will be approached in stages, as a long-term 
endeavor with sustainable impact and emphasis on extramural programs (Table).

This strategy is based upon the premise that it is far less costly, in both 
human suffering and economic terms, to anticipate and prevent infectious 
diseases than to react with expensive treatment or containment measures to 
unanticipated public health crises. Implementation of this plan does not 
guarantee that a microorganism will not cause disaster. However, investments
in surveillance, laboratory research and training, epidemiologic 
investigations, and integration with prevention and control efforts will 
ensure that we are better prepared to respond to emerging infectious disease
threats and to lessen their impact. It is crucial that emerging infectious 
diseases be addressed and that the basic tenets of prevention-oriented 
public health policy form an integral component of our nation's efforts to 
safeguard health in our communities.

Table.  Implementation: High Priorities for 1994-1996

Goal I: Surveillance

Strengthen notifiable disease surveillance at the state and local levels.

Establish two physician-based Sentinel Surveillance Networks to detect and 
monitor emerging diseases, such as unexplained adult respiratory distress 
syndrome, multidrug-resistant pneumococcal disease, and childhood illnesses
characterized by fever and rash.

Establish four population-based Emerging Infections Epidemiology and 
Prevention Centers to conduct focused epidemiology/prevention projects 
emphasizing foodborne and waterborne infectious diseases and potentially 
vaccine preventable diseases.  Strengthen and link four existing sites for a 
global consortium to promote the detection, monitoring, and investigation of 
infections emerging internationally that could affect the health of Americans.

Goal II: Applied Research

Reestablish an extramural program to support emerging infectious disease 
prevention and control activities, such as evaluating the role of 
prescribing practices in the development of antimicrobial drug-resistant 
pathogens.

Initiate prevention effectiveness studies to assess the impact of food 
preparation guidelines on the incidence of foodborne infections such as 
E. coli O157:H7 and Salmonella enteritidis.

Goal III: Prevention and Control

Develop additional means to deliver laboratory and public health information
informing health professionals about emerging infections and antimicrobial 
drug resistance.

Develop and implement guidelines for the prevention of opportunistic 
infections in immunosuppressed persons.

Goal IV: Infrastructure

Provide state-of-the-art training in diagnostic evaluation and testing for 
medical laboratory personnel to ensure the diagnosis and surveillance of 
emerging infections.

Establish a public health laboratory fellowship in infectious diseases that
will train medical microbiologists in public health approaches to diagnosis 
and molecular epidemiology.


Summary of Goals and Objectives
Goal I:     Surveillance
	    Detect, promptly investigate, and monitor emerging pathogens, 
	    the diseases they cause, and the factors influencing their 
	    emergence.

Objectives:

A.  Expand and coordinate surveillance systems for the early detection, 
    tracking, and evaluation of emerging infections in the United States.
B.  Develop more effective international surveillance networks for the 
    anticipation, recognition, control, and prevention of emerging 
    infectious diseases.
C.  Improve surveillance and rapid laboratory identification to ensure early
    detection of antimicrobial resistance.
D.  Strengthen and integrate programs to monitor and prevent emerging 
    infections associated with food/water, new technology, and environmental
    sources.
E.  Strengthen and integrate programs to monitor, control, and prevent 
    emerging vector-borne and zoonotic diseases.


Goal II:     Applied Research
	     Integrate laboratory science and epidemiology to optimize 
	     public health practice.

Objectives:

A.  Expand epidemiologic and prevention effectiveness research.
B.  Improve laboratory and epidemiologic techniques for the rapid 
    identification of new pathogens and syndromes.
C.  Ensure timely development, appropriate use, and availability of 
    diagnostic tests and reagents.
D.  Augment rapid response capabilities for vaccine delivery and expand 
    evaluation of vaccine efficacy and the cost effectiveness of vaccination
    programs.


Goal III:     Prevention and Control
	      Enhance communication of public health information about 
	      emerging diseases and ensure prompt implementation of 
	      prevention strategies.

Objectives:

A.  Use diverse communication methods for wider and more effective delivery 
    of critical public health messages.
B.  Establish the mechanisms and partnerships needed to ensure the rapid and
    effective development and implementation of prevention measures.


Goal IV:     Infrastructure
	     Strengthen local, state, and federal public health 
	     infrastructures to support surveillance and implement 
	     prevention and control programs.

Objectives:

A.  Ensure the ready availability of the professional expertise and support 
    personnel needed to better understand, monitor, and control emerging 
    infections.
B.  Make available state-of-the-art physical resources (laboratory space, 
    training facilities, equipment) needed to safely and effectively support
    the preceding goals and objectives.

_____

Background

The Concept of Emergence
Emerging infectious diseases are diseases of infectious origin whose 
incidence in humans has increased within the past two decades or threatens 
to increase in the near future.1  Many factors, or combinations of factors, 
can contribute to disease emergence (Table1). New infectious diseases may 
emerge from genetic changes in existing organisms; known diseases may spread
to new geographic areas and populations; and previously unknown infections 
may appear in humans living or working in changing ecologic conditions that 
increase their exposure to insect vectors, animal reservoirs, or 
environmental sources of novel pathogens. Reemergence may occur because of 
the development of antimicrobial resistance in existing infections (e.g., 
gonorrhea, malaria, pneumococcal disease) or breakdowns in public health 
measures for previously controlled infections (e.g., cholera, tuberculosis 
[TB], pertussis).


Table 1.  Factors in Emergence*
Categories                                      Specific Examples
________________________________________________________________________________
Societal events          Economic impoverishment; war or civil conflict; 
                         population growth and migration; urban decay
Health care              New medical devices; organ or tissue transplantation; 
                         drugs causing immunosuppression; widespread use of 
                         antibiotics
Food production          Globalization of food supplies; changes in food 
Human behavior           processing and packaging Sexual behavior; drug use; 
                         travel; diet; outdoor recreation; use of child
                         care facilities
Environmental changes    Deforestation/reforestation; changes in water 
                         ecosystems; flood/drought; famine; global warming
Public health            Curtailment or reduction in prevention programs; 
infrastructure           inadequate communicable disease surveillance; lack 
                         of trained personnel (epidemiologists, laboratory
                         scientists,, vector and rodent control specialists)
Microbial adaptation     Changes in virulence and toxin production; 
and change               development of drug resistance; microbes as 
                         cofactors in chronic diseases
__________________________________________________________________________________ 
*Adapted from reference 1.

The Problem
In the United States and elsewhere, infectious diseases increasingly 
threaten public health and contribute significantly to the escalating costs 
of health care. As society, technology, and the environment change, 
pathogens evolve or spread, and the spectrum of infectious diseases expands.
Emerging infectious diseases such as acquired immunodeficiency syndrome
(AIDS) and TB vividly illustrate that no nation can be complacent regarding 
human vulnerability to the microorganisms with which we share our 
environment.

Although many serious infectious diseases are largely or completely 
preventable, current approaches to health care, which neglect public health,
hamper our ability to control them effectively. For too long, health policy
in the United States has been treatment-driven rather than prevention-
oriented, reactive rather than proactive, and complacent rather than 
anticipatory and vigilant.   As a result, the public health infrastructure 
of this country is poorly prepared to confront the emerging disease problems
of a rapidly changing world (Figure 1). Examples of these problems are 
increasingly common and include diseases due to drug-resistant pathogens, 
such as Neisseria gonorrhoeae, staphylococci,Streptococcus pneumoniae, and 
enterococci; vector-borne or zoonotic diseases, such as hantavirus disease, 
Lyme disease, arboviral encephalitides, and rabies; foodborne and waterborne
illnesses, such as those caused by Escherichia coli O157:H7, Salmonella, and
Cryptosporidium; diseases in special settings, such as diarrhea, otitis 
media, and respiratory illnesses in child care facilities; vaccine-
preventable diseases, such as measles, polio, pertussis, and diphtheria in 
unimmunized populations; and the increasingly commonplace imported 
infections, such as cholera and malaria.

As the United States moves towards comprehensive health care reform, it is 
crucial that emerging infectious disease threats be addressed and that the 
basic tenets of prevention-oriented public health  policy form an integral 
component of plans for health care reform.

Timely recognition of emerging infections requires early warning systems to 
detect new infectious diseases before they become public health crises. 
Prompt detection of these new threats depends on careful monitoring by 
modern surveillance systems and a thorough understanding of trends in 
incidence and distribution of known infectious agents. However, existing 
systems to monitor these trends domestically and internationally are 
inadequate. For example, the true magnitude of the antimicrobial drug 
resistance crisis is unknown because of the absence of systematic monitoring.
Because international surveillance is severely limited, early detection of 
infections that are imported from abroad is often delayed. Also lacking is 
an effective laboratory-based surveillance system for the early detection of
exotic microbial agents that might be used for biological warfare or 
terrorist activities.

National surveillance for most reportable infectious diseases in the United 
States depends heavily upon voluntary collaboration between the Centers for
Disease Control and Prevention (CDC) and state and local health departments,
which in turn depend on physician-initiated reporting of a limited number of
specific, recognized infectious diseases. Reporting is generally incomplete. 

Results of a recent survey by the Council of State and Territorial 
Epidemiologists (CSTE) illustrate the inadequacy of existing infectious 
disease surveillance by documenting the limited number of professional 
positions dedicated to infectious disease surveillance in most states. For 
example, in 12 of the 50 states surveyed, no professional position is 
dedicated to surveillance of foodborne and waterborne diseases. Moreover, 
a small number of diseases command a large proportion of the limited 
resources. Although more than $40 million in federal funds are provided to 
states for infectious disease surveillance, more than 95 percent of these 
funds are limited to surveillance of diseases in four categories (TB, human 
immunodeficiency virus [HIV]/AIDS, sexually transmitted diseases [STDs], and
selected vaccine-preventable diseases).6 

No federal resources are provided to state and local health departments to 
support the national notifiable disease system. In addition, the ability of 
state public health laboratories to support surveillance and control of 
infectious diseases has diminished, and critical health department services, 
such as insect vector and rodent control programs, have been dismantled in 
many states.

In addition to comprehensive and innovative surveillance systems, effective 
preparation for emerging infectious diseases requires professional expertise,
laboratory support, and research capability. These foundations support the 
infrastructure needed to address the ongoing, but often changing, threats 
from emerging infections. Despite the continued emergence of such threats, 
support for applied research and control efforts has declined over the past 
decade for most infectious diseases.

As highlighted in three recent reports by expert committees convened by the 
National Academy of Science's Institute of Medicine (IOM), the ability of 
the U.S. public health system and our health professionals to deal with 
emerging infectious disease problems is in jeopardy.1,7,8 

The earliest of these reports, "The U.S. Capacity to Address Tropical 
Infectious Disease Problems",7 published in 1987, documented our poor state
of readiness to recognize, treat, or control infectious disease threats 
emanating from the tropics regions which have yielded microbial threats such 
as Lassa fever and Ebola viruses, chloroquine-resistant malaria, and 
penicillin-resistant gonorrhea. 

The second report, "The Future of Public Health," published in 1988, 
concluded that the U.S. public health system is in disarray. It emphasized 
that the United States approach to public health has too often been crisis 
driven or reactive, rather than proactive, an approach that is costly 
because it blocks our ability to institute cost-saving preventive strategies.8

The third IOM report, "Emerging Infections, Microbial Threats to Health in 
the United States", published in 1992, emphasized the ongoing threat to 
domestic and global health from emerging infectious diseases and noted that 
increased vigilance is needed to overcome years of complacency (Figure 2).1  
The report provided specific recommendations for CDC, the National Institutes 
of Health (NIH), the Food and Drug Administration (FDA), the Department of 
Defense (DOD), and other federal and state agencies for addressing microbial 
threats to health in the United States and elsewhere. This report emphasized 
a critical leadership role for CDC in a national and global effort to prevent 
and control emerging infectious diseases.

Figure 2.  Institute of Medicine report, "Emerging Infections:  Microbial 
Threats to Health in the United States," National Academy Press, 1992

The Burden of Infectious Diseases

Infectious diseases remain the leading cause of death worldwide.9,10 Reduction 
in mortality from many infectious diseases has been described as the single 
most significant public health achievement of the past century.11  
Unfortunately, historical successes in treating and controlling some of 
these diseases left many health policymakers with the false perception that 
the threat to public health from infectious agents had all but disappeared.
The resulting public health complacency has been costly in both human and 
economic terms.12

Emerging infections contribute substantially to the ongoing burden of 
infectious diseases on the American public. Childhood ear infections, the 
leading cause of visits to pediatricians, increased 150% between 1975 and 
1990.13 Infectious diseases account for 25% of all visits to physicians each
year, and antimicrobial agents are the second most frequently prescribed 
class of drugs.10,14

Infectious agents may be causing diseases previously considered 
noninfectious (Table 2). Helicobacter pylori infections, for example, have a
well established association with peptic ulcer disease;15 sexually transmitted
human papillomavirus is associated with cervical cancer;16 and hepatitis C 
virus is now recognized as a leading cause of chronic liver disease and 
cirrhosis in the United States with an estimated 150,000 new infections per 
year.17 Chlamydia infections have long been implicated in infertility and more
recently have been tentatively associated with coronary artery disease.18 
Rodentborne hantaviruses may play a role in hypertensive renal disease.19 
Other chronic diseases with possible viral origins include Sjgren syndrome,
multiple sclerosis, Alzheimer disease, Kawasaki disease, and juvenile onset
diabetes mellitus.10

Direct and indirect costs of infectious diseases are staggering. The annual 
treatment of non-AIDS STDs, for instance, costs $5 billion, and intestinal 
infections result in almost $30 billion in combined direct costs and lost 
productivity each year.10  Annual direct medical costs due to nosocomial 
infections reached $4.5 billion in 1992,20-21 and the National Foundation for 
Infectious Diseases estimates that yearly expenditures incurred from 
antimicrobial resistance approach $4 billion and are increasing.

Estimated costs for some infectious agents are equally staggering. For 
example, influenza produces direct medical costs approaching $5 billion and 
lost productivity costs of almost $12 billion per year.10 Salmonella and 
Campylobacter infections each produce $1billion in economic losses yearly. 
Hepatitis B virus infection costs over $720 million each year, while other
important emerging pathogens, such as rotavirus and Giardia lamblia, result 
in annual costs (direct and indirect) of $200-400 million and $120 million, 
respectively.20

These illustrative costs, combined with dollars spent on HIV-related illness,
exceed $120 billion. These figures and other measures, however, most likely 
underestimate the impact of infectious diseases. The International 
Classification of Diseases (ICD-9) places many infectious diseases in 
non-infectious categories (such as the classification of endocarditis among 
cardiovascular diseases and the classification of meningitis and middle ear 
infections among diseases of the nervous system and sense organs, 
respectively). Clearly, infectious diseases contribute significantly to 
economic losses and days of disability in the United States.

Important Examples of Emerging Infectious Disease Threats

Emerging infectious diseases that threaten U.S. public health originate from
both domestic and international sources.22 Toxic shock syndrome (TSS) and Lyme
disease illustrate how new technology or products (super-absorbent tampons)
and changing ecology and human demographics (reforestation, increased deer 
populations, suburban migration) can foster the emergence of new microbial 
threats.23,24 

Other societal changes, such as the expanding use of child care facilities, 
have contributed to the emergence of infectious diseases that threaten 
children and staff in child care centers as well as the children's household
contacts. Recent examples of infectious disease threats related to child 
care include E. coli O157:H7 infection, shigellosis, giardiasis, 
cryptosporidiosis, hepatitis A, and rotavirus infection.25

Also, despite new standards of health care delivery within modern, well-
equipped clinical facilities, hospital-acquired infections affected an 
estimated 2 million persons in 1992 alone.21 The staff and employees of clinical
facilities are also at risk for infections that can be occupationally 
acquired, such as TB and hepatitis B. Moreover, an increasing percentage of
our population is elderly, and a growing number of persons are 
immunosuppressed because of HIV infection, organ transplantation, or cancer 
chemotherapy. These populations are at increased risk for emerging 
infections, and their medical management is complex and costly. Specifically,
these populations are highly susceptible to opportunistic infections, and an
ever-expanding array of such infections is being seen in patients with AIDS 
and other forms of immunosuppression. The identification of certain 
opportunistic pathogens in immunosuppressed populations has led to the 
recognition of these agents in persons with normal immunity; this happened
with Cryptosporidium and is currently occurring with Rochalimaea species and
microsporidia.26-31

Changes in dietary habits, food processing and packaging, and globalization 
of the food supply are contributing to an increase in illnesses due to 
foodborne infections. Infectious agents continue to contaminate the national
food supply, as evidenced by recent outbreaks of serious diarrheal illness 
associated with the consumption of raw milk, domestic cheese, eggs, and 
commercial airline food.32-37  Powdered milk products and infant formula have 
been contaminated with diarrhea-causing bacteria.38  Seafood is increasingly 
implicated as the source of infectious disease outbreaks due to hepatitis A 
virus, Norwalk virus, Vibrio species, and Clostridium botulinum,39,40 and is the 
source of illness associated with marine biotoxins (paralytic, diarrheal, 
and amnesic shellfish poisoning; scombroid and ciguatera fish poisoning), 
which often occur during periods of marine algae overgrowth (algal blooms or
red tides) in coastal waters in the United States and elsewhere.41,42 

Other commonly consumed food items contaminated with infectious agents may 
place large numbers of persons at risk. In early 1993, for example, 
hamburgers contaminated with the bacterial pathogen E. coli O157:H7 and 
served at a fast-food restaurant chain (at least 93 restaurants were 
implicated) caused a multi-state outbreak of severe bloody diarrhea 
(hemorrhagic colitis) and serious renal disease (hemolytic uremic syndrome 
[HUS]). Data from the ongoing investigation of this outbreak indicate that 
over 500 children and adults became ill, and four children died (Figure 3A).43,44


Figure 3.  Emergence of Foodborne and Waterborne Pathogens

Increasingly, outbreaks of gastrointestinal illness due to contaminated 
municipal water such as the outbreak of cryptosporidiosis in Milwaukee, Wis., 
in April 1993 that affected hundreds of thousands of people (see Figure 3B; 
Box) are associated with viral and parasitic infectious agents.45,46

Waterborne Cryptosporidiosis

In the spring of 1993, the outbreak of waterborne cryptosporidiosis in the 
greater Milwaukee area caused prolonged diarrheal illness in approximately 
403,000 persons, 4,400 of whom required hospitalization. Attack rates were 
as high as 50% in some parts of the city. In the United States, existing 
surveillance systems are inadequate to rapidly recognize outbreaks of this 
parasitic infection. Early recognition of Cryptosporidium as a cause of 
widespread diarrheal illness would implicate common sources, such as 
municipal water supplies, sooner and likely prevent significant numbers of 
new infections by the early institution of preventive interventions, such as
boil water advisories. Future outbreaks of this emerging parasitic infection
could be prevented or controlled through improvements in water quality 
monitoring, use of appropriate diagnostic tests, and surveillance to 
evaluate the effectiveness of regulations and other control measures.

Exposure to certain animals is also placing Americans at risk for emerging 
infectious diseases. Hantavirus pulmonary syndrome (HPS), first detected in 
the southwestern United States in 1993, has been linked to exposure to 
infected rodents in more than a dozen states. More than 50 cases have been 
detected, and more than half of those infected have died (see Box, page 32).47-50 

Emerging infectious disease threats from abroad are also increasing. Cholera
has recently returned to the Western Hemisphere in epidemic proportions 
after almost a century's absence (Figure 4). Through October 1993, at least 
900,000 cases of infection were detected, and more than 8,000 persons died. 
The Pan American Health Organization (PAHO) estimates that it will take more
than a decade and more than $200 billion to control the current pandemic in 
Latin America. Although cholera initially reemerged in Peru, the disease has
occurred throughout Latin America, and cases have been imported into the 
United States, where more cases occurred in 1992 than in any other year 
since cholera surveillance began in 1962.36,51  Moreover, the V. cholerae O1 
strain responsible for cholera in Central and South America has been 
isolated from oysters and oyster-eating fish captured in oyster beds along 
U.S. Gulf Coast waters.52  More recently, a newly described toxigenic strain 
of V. cholerae, V. cholerae O139, has emerged in southern Asia where it is 
causing epidemic cholera-like illness and has largely replaced V. cholerae 
O1 strains in many areas. Standard diagnostic tests for cholera are 
inadequate for this new strain, and neither current vaccines nor prior 
infection with V. cholerae O1 is protective. This new form of cholera is 
spreading, and an imported case has occurred in a U.S. traveler returning 
from India.53

Figure 4.  Spread of Epidemic Cholera-Latin America, 1991-1993

Similarly, various parasitic diseases, once considered exotic in the United 
States, are emerging or re-emerging as public health threats. Local 
transmission of malaria, for instance, has been observed since 1986 among 
Hispanic immigrants and residents of an affluent area of San Diego County,
Calif.54 In North Carolina, severely ill, malaria-infected Southeast Asian 
refugees have seriously strained the laboratory and health care delivery 
services at state and local health departments.55 Elsewhere, such as the 
metropolitan New York City area, multiple cases of locally acquired 
neurocysticercosis have been attributed to transmission from immigrant 
household workers.56

These and other examples suggest that the concept of "domestic" as distinct 
from "international health" is outdated. Such a dichotomous concept is no 
longer germane to infectious diseases in an era in which commerce, travel, 
ecologic change, and population shifts are intertwined on a truly global 
scale.57,58

Antimicrobial Drug Resistance

Antimicrobial resistance as a factor in emergence warrants considerable 
emphasis. Since antimicrobial agents were introduced for general use in the 
1940s, substantial reductions in deaths from many bacterial and parasitic 
diseases have been documented. However, as a consequence of widespread 
antimicrobial use, drug resistance has emerged in the United States and 
abroad as a major public health crisis both in community and institutional 
settings. Drugs that once seemed invincible are losing their effectiveness 
for a wide range of community-acquired infections, including TB, gonorrhea, 
pneumococcal infections (a leading cause of otitis media, pneumonia, and 
meningitis), and for hospital-acquired enterococcal and staphylococcal 
infections (Figure 5). Resistance to antiviral (e.g., amantadine-resistant 
influenza virus and acyclovir-resistant herpes simplex), antifungal (e.g., 
azole-resistant Candida sp.), and antiprotozoal (e.g., metronidazole-resistant 
Trichomonas vaginalis) drugs is also emerging, and drug-resistant malaria has 
spread to nearly all areas of the world where malaria occurs. Concern has 
also arisen over strains of HIV resistant to antiviral drugs. Increased 
microbial resistance has resulted in prolonged hospitalizations and higher 
death rates from infections, has required much more expensive, and often 
more toxic, drugs or drug combinations (even for common infections), and has 
resulted in higher health care costs.59

Figure 5.  Increasing Incidence of Vancomycin-Resistant Enterococci in U.S. 
Hospitals by Year-National Nosocomial Infections Surveillance System (NNIS),
1989-1993

Surveillance of Emerging Infections

Surveillance is the single most important tool for identifying infectious 
diseases that are emerging, are causing serious public health problems, or 
are diminishing in importance. The morbidity, mortality, and cost of 
infectious diseases can be measured through surveillance. The quality of 
the nation's health care system and effectiveness of health regulations (e.g
., microbial safety of food and water) can only be adequately assessed if 
effective surveillance systems are in place.

The varied strata of modern society present numerous challenges to 
surveillance. For example, assessing the health of traditionally underserved
or transient populations, such as migrant workers, the homeless, or inner-
city minorities, is difficult, but such populations are often the first and 
most seriously affected by emerging infectious diseases. Health care 
delivery and earlier recognition of emerging infectious diseases are 
enhanced when susceptible populations are targeted for surveillance. 
Emerging infectious threats from abroad challenge existing surveillance 
capabilities because global surveillance of emerging infections is 
fragmentary at best.

In addition to monitoring specific diseases and syndromes, gathering 
information about the numerous factors that affect disease emergence is also
important. Understanding and controlling arthropod- or rodentborne diseases,
for example, require knowledge of the geographic distribution of potential 
reservoirs and vectors. Changing ecologic developments, such as changes in 
land use, may enhance the emergence of infectious diseases, such as Lyme 
disease, by altering the distribution of vectors or placing greater numbers 
of persons in closer contact with vectors and animal or environmental 
reservoirs of novel pathogens that previously had little contact with 
potential human hosts.

Monitoring the development of antimicrobial drug resistance or enhanced 
virulence in known pathogens can also facilitate early intervention, prevent
morbidity and mortality, and reduce costs. For example, reliable information
about drug-resistant S. pneumoniae is needed to guide clinicians who treat 
such common infections as pneumococcal pneumonia in adults and otitis media
in children.60,61 Changes in virulence, such as those in certain subtypes of 
group A streptococcus, underscore the public health importance of monitoring
trends in virulence characteristics of known pathogens.62 Similarly, changing
antigenic structures of known pathogens, such as antigenic drift in measles 
virus, should be closely monitored, so that necessary changes in vaccine 
composition can be implemented promptly if indicated.63 Ongoing assessments of
drug and vaccine availability can also identify potential shortages, and 
careful monitoring of antimicrobial drug use will be essential to managing 
the current crisis of antimicrobial drug resistance.64

Understanding Emerging Infections Through Applied Research

Developing appropriate responses and control strategies for emerging 
infectious disease threats depends on linking laboratory science and 
epidemiology with public health practice. Innovative approaches to combining
surveillance and applied research are essential for controlling infectious 
diseases.65 Epidemiologic studies, including investigations of both outbreaks 
and sporadic disease, are critical to the rapid identification of risk 
factors for new diseases and provide important prevention information early 
in the evolution of a potential epidemic. Such studies are often the first 
integral step toward identifying the cause of an infectious disease outbreak. 
Other areas of applied research in infectious disease epidemiology needed to
address emerging diseases include economic analyses of the impact of 
emerging infectious diseases and cost-effectiveness analyses of proposed 
interventions, the study of behaviors that affect risk, and measurement of 
the effectiveness of public health interventions.

When a new or previously unrecognized infectious disease is suspected, 
clinicians, epidemiologists, and laboratorians work together to obtain case 
histories and collect and evaluate tissue and serum specimens. Such 
multidisciplinary efforts include the expertise of infectious disease 
pathologists, molecular biologists, and others with critical laboratory 
skills who coordinate their activities to confirm the etiologic agent and 
develop diagnostic tools for the identification of subsequent cases. A 
timely example of this process is the ongoing investigation of hantavirus 
pulmonary syndrome.47-50

Establishing the causes of emerging infectious diseases is fundamental to 
controlling these diseases. Rapid and accurate diagnostic testing 
capabilities for agents such as Mycoplasma are lacking in the United States.
In addition, tests designed for use in developing countries, for example, 
must be practical for field use in areas where expensive reagents and 
reliable power supplies may not be readily available.

Proper readiness for emerging infectious threats also requires that 
diagnostic tests for the many new pathogens likely to be encountered be made
available to clinical and reference laboratories as soon as it is 
technologically feasible. Promoting and teaching laboratory techniques 
appropriate for public health purposes are also critical. The lack of such 
training for testing of stool specimens for E.coli O157:H7 and 
Cryptosporidium, for example, has resulted in delayed recognition of 
outbreaks. Providing these tools and services will require ongoing federally
supported intramural and extramural efforts that target the development and 
application of rapid diagnostics for emerging pathogens.

The interaction of epidemiology (including surveillance) and laboratory 
science extends into several other areas of applied research that are 
relevant to emerging infections. Vaccine development, for example, includes 
the ongoing assessment of potential vaccine components, evaluation of 
vaccine efficacy, and studies of the cost-benefit of vaccination programs. 
Further, integrated approaches to the study of insect vectors and animal 
reservoirs are critical to understanding emerging vector-borne or zoonotic 
diseases such as rabies (Figure 6). In investigating HPS, for example, the 
integrated application of epidemiologic and molecular biologic techniques 
led to the rapid identification of rodents as carriers of the virus (see Box,
page 32). With this critical information, public health officials were then 
able to rapidly develop and disseminate prevention guidelines.47-50 Evaluating 
epidemiologic characteristics and how these diseases are maintained in 
nature will aid prevention efforts for Lyme disease, viral encephalitides, 
and other conditions in the United States and for many vector-borne or 
zoonotic infections worldwide, including malaria, trypanosomiasis, 
leishmaniasis, rickettsial diseases, and viral hemorrhagic fevers.

Figure 6.  The Expanding Epizootic of Racoon Rabies-Eastern United States, 
1979-1993

Other organisms, such as those that cause coccidioidomycosis, legionellosis,
or amoebic meningoencephalitis, do not have specific animal reservoirs but 
are maintained primarily in the soil or water; the emergence of these 
diseases may be particularly influenced by ecologic factors. It is also 
likely that the development of tropical habitats for human settlement and 
agriculture will increase opportunities for the emergence of new viral 
diseases and the prominence of several parasitic diseases in humans, but 
further research is needed to assess the magnitude of these risks and the 
specific factors that affect them.

Climatic changes, such as global warming, may broaden the distribution of 
vectors of tropical diseases and thus potentially increase their spread to 
new places.66 Furthermore, environmental control measures, such as the 
treatment of soil to prevent histoplasmosis or the use of insecticides to 
control insect-borne diseases, may sometimes be warranted, but expanded 
research is required to ensure that these measures are safe and cost-
effective.

Targeted research projects, such as the critical assessment of ecologic 
factors responsible for the recent large outbreak of coccidioidomycosis in 
central California or the emergence of epidemic Rift Valley fever and 
schistosomiasis associated with the damming of the Senegal River in Africa, 
should provide the information needed to prevent future outbreaks.

Finally, the recent outbreaks of foodborne and waterborne diseases highlight
the need for continuing evaluation of food and water processing practices 
affecting the emergence of infectious diseases.

_____

The CDC Prevention Strategy


The mission of CDC is to promote health and quality of life by preventing and 
controlling disease, injury, and disability. As the nation's prevention agency, 
CDC accomplishes its mission by working with partners throughout the nation 
and the world to monitor health, formulate prevention strategies, develop 
sound public health policies, implement prevention strategies, promote healthy 
behaviors, and foster safe and healthful environments. In keeping with this 
mission, CDC has strategic plans that address certain specific infectious 
disease threats, including HIV/AIDS, TB, STDs, and selected vaccine-preventable 
diseases. The concept of disease emergence has important implications for each 
of these.

Opportunistic infections in HIV-infected persons require cost-effective 
prevention strategies; drug resistance has become a barrier to TB control; 
STDs have been implicated as factors in chronic diseases (e.g., human 
papillomavirus and cervical cancer); and emerging diseases necessitate the 
ongoing assessment of vaccine development priorities (e.g., pneumococcal 
disease in children, respiratory syncytial virus [RSV] pneumonia, malaria). 
Strengthened efforts in the prevention and control of emerging infectious 
diseases will complement and improve the effectiveness of current efforts in 
HIV/AIDS, TB, STDs, and immunizations as well as other important infectious 
diseases.

To provide the vigilance and rapid response required to effectively address 
emerging infectious diseases, significant improvements in public health policy, 
program design, and infrastructure are needed. A far-reaching and comprehensive 
strategy, carefully integrated with broader plans for health care reform, is 
required. The CDC plan described below contains four critical goals that 
address specific IOM recommendations in the context of a broader vision for 
revitalizing our nation's ability to detect, contain, and most importantly, 
prevent the emerging infectious diseases that threaten populations both here 
and abroad.

This plan reflects the commitment of CDC to work with its partners in health 
departments, clinical practice, academia, private industry, and international 
health to meet the challenge of important emerging public health problems. It 
also embodies CDC's mission to prevent and control infectious disease, and 
addresses high priority infectious diseases in disadvantaged populations and 
underserved minorities, women, and children. Implementation of this plan with 
emphasis on extramural programs will strengthen the public health 
infrastructure in the United States at the local, state, and federal levels, 
and contribute to strengthening global surveillance networks. Most importantly, 
implementation of this plan will help the public health system identify, 
control, and prevent new, emerging, and drug-resistant diseases before they 
cause widespread epidemics, thereby reducing the cost of infectious diseases 
and improving the health and welfare of all Americans.

Goals and Objectives

Goal I
Detect, promptly investigate, and monitor emerging pathogens, the diseases 
they cause, and the factors influencing their emergence.

Objective I-A.
Expand and coordinate surveillance systems for the early detection, tracking, 
and evaluation of emerging infections in the United States.

Surveillance serves several purposes: it characterizes disease patterns by 
time, place, and person; detects epidemics; suggests hypotheses and themes 
for epidemiologic investigation; evaluates prevention and control programs; 
and projects future health care needs.67,68  In addition to monitoring and 
identifying needed public health responses for known infectious diseases, a 
well-functioning surveillance system maintains vigilance for emerging 
infectious diseases. The ability to detect what is new or emerging depends on 
the capacity to identify and track the routine as well as the unusual. 
National surveillance requires adequate infrastructure, including trained 
personnel, within the states and local communities and timely communications 
among state and local health departments, public and private laboratories, 
health care providers, and CDC.

Activities
i.
Improve surveillance for reportable infectious diseases by reevaluating 
current reporting mechanisms and requirements and providing technical and 
financial assistance to state health departments.

National infectious disease surveillance systems form the foundation of our 
ability to know and track the routine. Certain infectious diseases such as 
multidrug-resistant (MDR) TB, meningococcal meningitis, and botulism warrant 
prompt detection of all cases because they cause substantial morbidity and 
mortality, require specific public health interventions, or may signal a 
potential outbreak. State and local public health authorities, other 
infectious disease experts, and CDC will reexamine currently reportable 
diseases, establish criteria for making a disease reportable, and explore 
ways to enhance rapid reporting of cases from clinical laboratories and 
health care practitioners. States must also examine the need to develop 
statutory requirements for clinical laboratories to submit isolates of 
designated organisms of public health importance to the state laboratory. 
National infectious disease surveillance must be flexible enough to include 
newer problems, such as E. coli O157:H7-associated HUS, multidrug resistance 
in common pathogens (e.g., S.pneumoniae, Mycobacterium tuberculosis), and 
hantavirus pulmonary syndrome, and to reexamine the benefit of including 
currently reportable conditions, such as aseptic meningitis.

National notifiable disease surveillance is organized around state by state 
reporting systems for which states have ample legal authority. However, 
limited resources have left many state and local health departments with 
inadequate capacity to conduct surveillance for most infectious diseases. CDC 
could help ensure better capacity through cooperative agreements that provide 
financial and technical assistance, including training, to health departments.

ii.
Expand the use of Sentinel Surveillance Networks to complement other 
surveillance methods for detecting and monitoring emerging infections.

The use of sentinel events to enhance surveillance is an effective public 
health tool that has proven useful in the monitoring of many diseases. 
Sentinel networks, linking groups of participating individuals or 
organizations to a central data receiving and processing center, have been 
particularly helpful in monitoring specific infections or designated classes 
of infections. Examples of such networks currently in use at CDC are the NNIS 
system (see Box),69 the domestic influenza surveillance network (see Box), the 
National Respiratory and Enteric Virus Surveillance System, and the Pediatric 
and Adult/Adolescent Spectrum of HIV Disease Projects.

The National Nosocomial Infection Surveillance System
The NNIS system is an ongoing collaborative surveillance system among U.S. 
hospitals and the only national source of nosocomial infections data in the 
United States. This system is used to identify changing patterns in 
nosocomial infection characteristics, such as risk factors, patient infection 
sites, drug resistance, and emerging pathogens. Data are collected 
prospectively, using standardized surveillance components and nosocomial 
infection definitions.

Increasing the number of NNIS system hospitals allows for a more accurate 
estimate of the distribution and rates of various types of nosocomial 
infections while enhancing our ability to detect emerging pathogens.

In 1993, 163 hospitals voluntarily participated in the NNIS system. With 
adequate support, the system will continue to find more effective and 
efficient ways to characterize nosocomial infections and to assess the 
potential influences of patient risk factors, changes in hospital-based 
health care delivery, and modifications of infection control practices on the 
emergence of infectious diseases in the hospital setting.

Priority issues for future NNIS efforts include the following: surveillance 
of occupationally acquired infections in health care workers; broadening the 
scope of data collection to recognize nosocomial infections resulting in 
illness after patients are discharged from the hospital or other health care 
settings, such as out-patient surgical facilities; and detecting and 
monitoring selected community-acquired syndromes in hospitalized patients.

Sentinel Surveillance for Influenza
Domestic
The influenza sentinel physician surveillance network was established through 
the American Academy of Family Physicians and includes approximately 150 
primary care physicians located throughout the United States. These 
physicians submit weekly reports of the number of patients seen with 
influenza-like illness by age group per number of patient visits, as well as 
the number of hospitalizations among patients with influenza-like illness. A 
subgroup (approximately 75 physicians) also collects nasopharyngeal specimens 
that are sent to a central laboratory for influenza virus identification. 
This system provides direct community influenza morbidity data that are 
otherwise unavailable.

International
An international network of collaborating laboratories was established in 
1947 to monitor the emergence and spread of new epidemic and pandemic strains 
of influenza. This network now includes three World Health Organization (WHO) 
Collaborating Centers and approximately 120 WHO National Collaborating 
Laboratories. The primary purpose of this network is to detect, through 
laboratory surveillance, the emergence and spread of antigenic variants of 
influenza that may signal a need to update the strains contained in the 
influenza vaccine. To augment the WHO network, CDC supports a surveillance 
system for year-round influenza isolation in six sites in China, where many 
pandemic and epidemic strains have first appeared. The importance of these 
surveillance programs is underscored by the fact that viruses from the China 
surveillance system have been recommended for inclusion in the U.S. vaccine 
for the past 5 years.

Table 3.  Proposed Sentinel Surveillance Networks
Blood Banks
Clinical Microbiology Laboratories
Emergency Rooms
Family Practitioners
Gynecologists
Infectious Disease Specialists
Internists
Medical Examiners
Pediatricians
Travel and Tropical Medicine Clinics

Expanded use of the sentinel network concept, including strengthening 
existing systems, will improve our ability to detect and monitor emerging 
infections. With the cooperation of state and local health departments, CDC 
proposes to establish a series of electronically linked Sentinel Surveillance 
Networks, organized according to information source, that will use novel as 
well as traditional data sources important to the assessment of emerging 
infections (Table 3). 

Networks among selected physicians' groups, for example, could provide early 
warning of emerging syndromes of uncertain but possibly infectious origin, 
such as febrile diarrheal illnesses, meningitis, or encephalitis. Clinician- 
or laboratory-based networks also provide a mechanism for rapid 
interaction/consultation among members when unusual syndromes, such as 
unexplained adult respiratory distress syndrome (ARDS), idiopathic CD4 
lymphopenia, or eosinophilia-myalgia syndrome, or when new or unusual 
laboratory isolates are detected . Such networks may also provide a more 
effective means for monitoring occupationally acquired infections in hospital 
and laboratory personnel.

Other networks could focus on the emergence of drug-resistant pathogens 
(e.g., clinical microbiology laboratories) or changes in seroprevalence of 
known diseases (e.g., blood banks). Special consideration will also be given 
to the formation of veterinary networks to monitor established zoonotic 
diseases (e.g., brucellosis, salmonellosis, cryptosporidiosis) or the 
increasing incidence of animal infections with zoonotic potential (e.g., 
bovine TB, bovine spongiform encephalopathy). An initial priority will be to 
establish a network of physicians (in cooperation with professional societies), 
to monitor such conditions as unexplained ARDS, meningoencephalitis of 
unknown etiology, and multidrug-resistant pneumococcal disease, or to 
investigate the increasing occurrence of rabies post-exposure prophylaxis.

iii.
Create population-based Emerging Infections Epidemiology and Prevention 
Centers to complement and support local, regional, and national surveillance 
and research efforts.

The proposed centers will be developed through cooperative agreements with 
local and state health departments, in collaboration with local academic 
institutions and other governmental or private-sector organizations, and will 
be strategically located in sites across the country that offer access to 
various population groups. Wherever possible, centers will build upon 
existing capacities and partnerships. In contrast to the Sentinel 
Surveillance Networks, the centers' purpose will be to forge strong links 
with local medical, public health, and community representatives in order to 
establish ongoing sources for population-based data as a foundation for a 
variety of surveillance and prevention research projects relevant to emerging 
infections (Figure 7). These centers will also provide excellent 
opportunities for training public health professionals through cooperative 
arrangements between health departments, academic centers, and joint CDC/NIH 
training programs in infectious disease epidemiology.

In addition to providing population-based information, they will allow access 
to special populations including the rural and inner-city poor; underserved 
women and children; the homeless; immigrants/refugees; and persons infected 
with HIV. Although their presence may facilitate the reporting of new 
infections or rare syndromes recognized by health professionals in the area, 
these centers are not expected to significantly improve our ability to 
actually detect previously unknown or unrecognized infectious diseases. 
Rather, they are designed to assess the public health impact of emerging 
infections and to evaluate methods for their diagnosis, prevention, and 
control.

These population-based centers will provide a powerful tool for integrating 
information from many different places and sources, and about different 
emerging diseases. At the same time, national trends can be evaluated by 
combining information from the same project conducted at several centers 
across the country. Centers will maintain the flexibility to accommodate 
changes in specific projects as the need for information changes. Some 
projects will be conducted at all centers, while others might be carried out 
in only a few (Figure 7).

Priority activities will include the following:

Conducting active population-based surveillance projects to obtain detailed 
information about selected diseases for which adequate information is 
unavailable, such as foodborne infections (See boxes).

Conducting special projects, such as evaluation of new diagnostic tests for 
Lyme disease; evaluation of illnesses often not specifically diagnosed but 
whose trends and etiologic information are important (e.g., diarrhea, 
community-acquired pneumonia); and investigation of the relationships 
between infections and chronic diseases (e.g., hantavirus infections and 
hypertension, hepatitis C and chronic liver disease, and respiratory virus 
infections and asthma attacks).

Conducting behavioral surveillance projects designed to assess trends in 
behaviors that either increase or decrease risks for infectious disease 
(e.g., in food consumption, sexual behavior, travel, or exposure to animals).

Examining infectious diseases in the context of populations at risk, 
recognizing that the incidence of many emerging diseases will be highest 
among underserved populations.

Implementing and evaluating pilot prevention/intervention projects for 
emerging infectious diseases that focus on safe food preparation in the home, 
handwashing in child care settings, appropriate use of antibiotics in 
clinical settings and in the community, and personal protection devices for 
clinical and laboratory personnel potentially exposed to infectious agents.

Providing technical assistance; epidemiologic, behavioral science, and 
laboratory expertise; and training to other agencies, institutions, or 
organizations in a center's area.

 Hepatitis Sentinel Counties 
Although CDC conducts nationwide surveillance for acute viral hepatitis, 
underreporting and incomplete serologic testing and epidemiologic evaluation 
of all reported cases make it difficult to accurately assess changes in 
incidence of disease and risk factors associated with transmission.

To complement data collected nationally, a program of intensive surveillance 
for acute viral hepatitis was begun in Sentinel Counties in September 1979; 
since October 1981, it has been focused on four counties. These Sentinel 
Counties have provided precise data on the significant sources of viral 
hepatitis infection in the United States and the contribution of these 
sources to disease incidence.

In recent years, major changes have occurred in the incidence and 
epidemiology of the different types of viral hepatitis in the United States. 
Many of these changes were first recognized in the Sentinel Counties. The 
incidence of hepatitis A increased after a decade of decline, and drug users 
became an important source of communitywide outbreaks; more recently there 
has been an increase in hepatitis A associated with male homosexual activity, 
suggesting unsafe sexual practices. For hepatitis B, the disease transmission 
patterns in the Sentinel Counties showed that the immunization strategy that 
focused on adults at high risk had no impact on the incidence of disease. 
These data provided the rationale for a nationwide recommendation for 
universal infant hepatitis B vaccination (Advisory Committee on Immunization 
Practices [ACIP], 1991).

Testing of stored sera from acute and chronic non-A, non-B (NANB) hepatitis 
cases identified in the Sentinel Counties was used to show that the recently 
discovered hepatitis C virus was responsible for most NANB hepatitis in the 
United States. These counties have been the primary source for data 
describing the epidemiology and natural history of community acquired 
hepatitis C, and its importance as a cause of acute and chronic liver disease 
in the United States.17   Although national data remain important for hepatitis 
surveillance, more detailed data, including behavioral risk factor data, are 
needed to plan and evaluate prevention programs.

Population-based Active Surveillance Project
CDC, together with state and local health departments and university-based 
investigators, conducts population-based active surveillance for bacterial, 
mycobacterial, and fungal diseases. 

This project uses common infrastructures in population-based study sites to 
conduct surveillance, collect epidemiologic information, and gather isolates 
for laboratory study. 

Active population-based surveillance, integrated with epidemiologic studies 
and laboratory study of surveillance isolates, has been a powerful way to 
study bacterial and mycotic diseases. Examples have included studies of 
listeriosis that led to dietary recommendations to reduce the risk for this 
disease; evaluation of the efficacy of new vaccines for Haemophilus 
influenzae type b (Hib) disease; documentation of increased risk for invasive 
Hib disease in HIV-infected men; evaluation of risk factors for neonatal 
group B streptococcal disease and of invasive group B streptococcal disease 
in adults; descriptive epidemiology and evaluation of risk factors for 
cryptococcal disease; and assessment of the efficacy of pneumococcal vaccine 
in HIV-infected persons.

Using a common infrastructure provides economies of scale in conducting 
studies as well as several other advantages. The impact of several diseases 
can be compared directly when they are studied in the same population during 
the same periods. For a given disease, temporal trends can be evaluated 
reliably, and monitoring of the impact of prevention plans can be facilitated.

iv.
Expand field investigative and epidemic response capabilities.

To address emerging infectious disease threats more effectively, CDC must 
build upon one of its essential strengths the ability to conduct "shoe leather" 
epidemiologic field investigations. These field activities are essential to 
the rapid application of epidemiologic and laboratory expertise to prevent 
outbreaks from developing into broader public health crises.

CDC resources, including those that provide field training experiences for 
epidemiologists-in-training (Epidemic Intelligence Service [EIS] Officers 
conducting "Epidemic Aids") are not sufficient to provide all necessary support 
for outbreak investigations of emerging infectious diseases, which often 
require the presence of laboratorians, senior staff epidemiologists, and 
others in the field. The need to provide such additional support arose 
frequently in 1993 when CDC and state and local health department resources 
were severely strained in efforts to investigate and contain emergent disease 
threats, such as hantavirus pulmonary syndrome in the southwestern United 
States, cryptosporidiosis in Milwaukee, and E. coli O157:H7 disease in 
western states.

The availability of personnel to support field investigations is critical 
(See section IV-A below). To rapidly and effectively address the outbreak of 
HPS, professional and support staff were reassigned for several months from 
other high priority programs (e.g., drug-resistant pneumococcal disease, 
rabies). The availability of contingency funds for field investigations and 
the maintenance of adequate depth in personnel infrastructure at CDC would 
help prevent such situations.

Rapid and efficient mobilization of funds and personnel requires 
well-established mechanisms that lessen the usual administrative restraints 
inherent to any bureaucracy. For example, international response capability 
could be improved by development of a well-standardized system for foreign 
health officials to notify CDC and obtain assistance on short notice. Once 
the need for a field investigation is recognized, a mechanism is needed to 
rapidly allocate funds, personnel, equipment, and supplies. 

To respond to emerging infectious disease threats, a designated 
administrative system is proposed to maintain and manage contingency funds, 
develop guidelines for notifying CDC and requesting assistance, and create 
mechanisms for the prompt allocation of resources (including equipment, 
products, and personnel) for surveillance and epidemiologic investigations.

v.
Assess and apply innovative tools (computer and communications technology) to 
facilitate collection, analysis, and dissemination of infectious disease 
surveillance information.

Infectious disease surveillance in the United States should utilize modern 
computing and communications technologies to transform data into usable 
information quickly and effectively. Accurate, efficient data transfer with 
rapid notification of key partners and constituents is critical to 
effectively addressing emerging infectious disease threats. However, existing 
systems at CDC and at state and local health departments require upgrading 
and modification to minimize future data incompatibilities and to enhance 
rapid communications between federal and state/local health agencies by using 
common data standards and application protocols. In addition, the systematic 
evaluation of new and innovative tools for the collection and analysis of 
epidemiologic and laboratory data will enhance the speed with which 
technological, mathematical, and statistical advances are brought into use in 
efforts to better understand emerging infections. Included in this process 
will be the appropriate evaluation and utilization of Secure networks for 
the transmission of sensitive information.  These are essential and should 
take advantage of the national communications infrastructure for information 
dissemination and networking (Internet) being developed through the proposed 
High Performance Computing and High Speed Networking Applications Act of 1993.

Automatic and direct reporting from physicians' offices, hospitals, and 
private and public laboratories.  Comprehensive health insurance and 
universal access to health care has the potential to facilitate this process 
and improve surveillance. Reporting would be received by state health 
departments as soon as cases are suspected or identified.

Computer-based patient record technology.  CDC participation in the 
development of this capability is important to ensure that these systems are 
potentially compatible with automated public health surveillance systems and 
maintain patient confidentiality.

Strategies to integrate existing and planned information systems.  Internet 
can provide the physical framework for improved information exchange and the 
establishment of "information superhighways" for public health. Internet 
application standards for information dissemination should be integrated into 
plans for existing (CDC WONDER) and planned (CDC INPHO network) systems. 
Existing CDC surveillance systems (e.g., NETSS, PHLIS) will need modifying, 
so that common standards and protocols are used and, therefore, data are 
stored in compatible formats and can be retrieved by easy-to-use interfaces.

Field applications of computer technology.  Examples include the use of 
electronic forms that recognize information hand-written with an electronic 
pen. Such devices could potentially reduce data entry efforts and errors, and 
are already in use by commercial shippers and police departments. These 
computers can also use cellular transmission links for real-time connections 
between field staff and central data processing operations, reducing the need 
to return to the office to download data.

Geographic information systems (GISs) and satellite imagery.  GISs allow 
geographically oriented information about disease distribution and occurrence 
to be visually and analytically linked to images of the environment. These 
images and data can include satellite-generated images, housing or other 
location data obtained from hand-held Global Positioning Systems (accurate to 
less than a meter), digitized street maps, and census data. The potential 
application of this technology to monitoring environmental changes that could 
affect the emergence of infectious diseases will be assessed.

New statistical and mathematical modeling methods.  New methods for analyzing 
time-space clustering, GIS data, and data from longitudinal studies need 
critical assessment for potential applications to the problems of emerging 
infections. Newer mathematical models can be used in both hypothesis 
generating and confirmatory analyses, and may provide excellent opportunities 
for the actual anticipation or forecasting of changes in the incidence or 
distribution of emerging or reemerging diseases. Mathematical models are also 
useful for predicting the relative success of alternative prevention 
strategies (e.g., oral animal rabies vaccine).

Objective I-B.
Develop more effective international surveillance networks for the 
anticipation, recognition, control, and prevention of emerging infectious 
diseases.

Although infectious disease threats often emerge in regions remote to the 
United States and are readily transported here,12,51-58,65,72 practical mechanisms for the 
early detection of such threats, such as international infectious disease 
surveillance systems, are rudimentary and limited to a few specific diseases. 
Effective approaches to surveillance on an international scale should include 
early detection capability and the capacity national, regional, or 
international to generate public health responses.72  However, public health 
infrastructure and infectious disease expertise vary widely from country to 
country. Even in industrialized nations, more timely and effective 
information exchange about emerging infectious disease problems is clearly 
needed.73,74  For many developing countries, where this task will be the most 
difficult, established infrastructures, such as those in place for polio and 
Guinea worm eradication efforts, and existing resources, such as those 
available from ministries of health; WHO, the U.S. Agency for International 
Development, DOD, NIH, and CDC regional laboratories or offices; universities; 
and non-governmental organizations can assist in efforts to improve 
international cooperation in detecting and evaluating emerging infectious 
disease threats.

Activities
i.
Establish mechanisms for timely and systematic information exchange between 
public health agencies of different countries about emerging infectious 
diseases.

Improved links among public health officials in different countries are 
needed to facilitate information exchange regarding trends in disease 
emergence and antimicrobial resistance.73,74 CDC will work with ministries of 
health and international agencies to encourage exchange of surveillance 
information, adoption of compatible surveillance formats, and implementation 
of electronic data reporting and dissemination. The Internet international 
computer network system could facilitate efficient exchange of information. 
An international infectious disease database will be developed along the 
lines of the proposed U.S. Infectious Diseases Database described below 
(See Objective III-A, v).

ii.
Establish a global consortium of closely linked epidemiology/biomedical 
research programs/centers to promote the detection, monitoring, and 
investigation of emerging infections.

The proposed global consortium will be established in close collaboration 
with local ministries of health and international agencies. The consortium 
will operate under the direction of an international steering committee, 
possibly chaired by WHO, with representatives from CDC and other national 
and international organizations. A central office will coordinate operations 
of the consortium and will begin by reviewing the current and potential 
capabilities of existing research facilities and surveillance networks.

The committee will assign priorities and select sites for the proposed 
consortium. Areas of expertise considered critical to the consortium goals of 
improved detection, monitoring, and investigation of emerging infections 
include epidemiology, clinical and veterinary sciences, field ecology (e.g., 
mammalogy, entomology), behavioral science, laboratory microbiology, and 
related disciplines. To minimize startup costs and avoid lengthy delays, 
highest priority for initial inclusion in the consortium would be given to 
facilities that currently maintain expertise in several of these disciplines 
(Table 4).

Table 4.  Examples of Potential Members of a Global Consortium of 
Epidemiology/Biomedical Research Programs/Centers
Existing Networks

CDC Field Epidemiology Training Programs 
PAHO Polio Eradication Surveillance System
International Clinical Epidemiology Network
International Office of Epizootics Worldwide Information System
WHO Arbovirus and Hemorrhagic Fever Collaborating Centers
WHO Global Influenza Surveillance Network

Existing Research Facilities

Caribbean Epidemiology Centre, Trinidad
CDC: National Center for Infectious Diseases Field Stations (Cote d'Ivoire, 
Guatemala, Puerto Rico, Kenya, Sierra Leone, Thailand)
DOD: U.S. Army Research Facilities (Brazil, Kenya, Thailand) and U.S. Naval 
Research Facilities (Egypt, Indonesia, Peru, Philippines)
Food and Agriculture Organization Reference Centers (Argentina, Brazil, 
Colombia, Czech Republic, France, Germany, Hungary, Kenya, Panama, Senegal, 
Spain, Sri Lanka, Thailand, UK, Uruguay, USA)
French Scientific Research Institute (e.g., Senegal, Congo, Cote d'Ivoire)
Instituto de Nutricin para Centro America y Panama, Guatemala
International Center for Diarrhoeal Disease Research, Bangladesh
NIH, National Institute of Allergy and Infectious Diseases Supported 
Facilities (e.g., Brazil, Colombia, Israel, Mali, Mexico, Philippines, Sudan, 
Uganda, Venezuela, Zimbabwe)
Pasteur Institutes (e.g., Algeria, Central African Republic, French Guiana, 
Iran, Madagascar, Morocco, New Caledonia, Senegal, Vietnam)

Consortium members will provide training and support to local and regional 
scientists and public health officials, assist in the formulation of public 
health policies, and aid outbreak investigations in the region.75 The 
facilities and expertise of the consortium would also enhance the likelihood 
of recognizing biological warfare events, an area of increasing international 
concern.  In addition to equipping consortium members with the ability to 
conduct certain critical tests under field laboratory conditions, laboratory 
and epidemiology back-up will be available from CDC and other collaborating 
organizations.

Objective I-C.
Improve surveillance and rapid laboratory identification to ensure early 
detection of antimicrobial resistance.

Organisms resistant to antimicrobial agents pose a special threat to public 
health. In addition to the significant economic impact of antimicrobial 
resistance, evolution toward a "post-antibiotic" era, when many antibiotics are 
ineffective, is rapidly becoming possible.76,77  Even drugs used in the treatment 
of common bacterial infections are becoming increasingly ineffective, 
resulting in prolonged illness and higher mortality rates. With the number of 
antimicrobial agents under development decreasing, alternative therapies for 
pathogens such as vancomycin-resistant enterococci may not be available 
(Figure 5).59,77  For example, FDA approved only five new antimicrobial agents in 
1991 and two in 1990, and no new class of antimicrobial drugs is likely to be 
available in the present decade.59 Managing pathogens that are already 
resistant and preventing the development of antimicrobial resistance in 
others will require a concerted, multidisciplinary effort.

Moreover, the problem of antibiotic resistance is global. Resistance can 
emerge rapidly and spread from one geographic area to another and from one 
organism to another. Recent examples include the international spread of 
multidrug-resistant Salmonella typhi and the introduction by travelers of 
drug-resistant Shigella to the United States.59,78,79

Activities
i.
Monitor trends in antimicrobial resistance patterns associated with both 
hospital- and community-acquired infections.

The development of antimicrobial resistance is a dynamic process requiring 
continual surveillance of organism susceptibility over time. The 
surveillance of drug resistance depends upon the development of standard 
procedures for organism detection and in vitro susceptibility testing, and 
the establishment of a system for regular reporting of resistance data to 
local, state, and national surveillance programs.

Internationally, the management of resistance problems will require extensive 
cooperation. A high priority for the global consortium of 
Epidemiology/ Biomedical Research Centers noted above (See Objective I-B, ii) 
will be to initiate a system for the international monitoring and reporting 
of antimicrobial susceptibility data.

Rapid compilation and analysis of national and international data are 
critical in providing timely guidelines to health care providers about 
antimicrobial therapy and in setting vaccine development priorities 
(See Objectives III-A,iv; III-B,i). For example, as antimicrobial resistance 
in S. pneumoniae emerges, practical information about the extent and 
distribution of this problem, in addition to modified treatment 
recommendations, is needed for clinicians to effectively care for patients 
with such common infections as pneumococcal pneumonia and otitis media.

ii.
Develop and evaluate tools for the reliable and rapid detection of 
antimicrobial resistance.

Rapid screening procedures for antimicrobial resistance will become 
increasingly important for preventing the spread of disease and for limiting 
illness and death from drug-resistant pathogens. For example, the rapid 
identification of rifampin resistance, a marker for MDR M. tuberculosis, 
would permit earlier initiation of appropriate antimycobacterial therapy in 
individual patients, thereby decreasing their risk for serious disease and 
shortening the time during which infection could be spread to others.80  The 
wider availability of such new techniques and their broader application to 
problems such as methicillin-resistant S.aureus,  vancomycin-resistant 
enterococci, and aminoglycoside or third generation cephalosporin-resistant 
Gram-negative bacilli will depend on continued development, standardization, 
and validation of these techniques.

iii.
Determine risk factors for emergence of resistance through applied 
epidemiologic research.

Risk factor analyses through appropriately designed epidemiologic studies are 
urgently needed to evaluate important aspects of antimicrobial resistance, 
such as the relationships between child care facilities and multidrug-
resistant S. pneumoniae;60 the use of antibiotics in livestock feed and 
resistant Salmonella;81 and predisposing clinical conditions or antibiotic use 
and vancomycin-resistant enterococci.77

Antimicrobial usage patterns in clinical practice and animal husbandry may 
significantly impact the emergence of resistant organisms through selective 
pressure, but further studies are needed to better characterize this impact 
and develop effective interventions. Molecular epidemiologic techniques, for 
example, have been useful in Sweden in tracing the potential spread to a 
human host of a trimethoprim-resistance gene in E. coli from antibiotic-fed 
swine.82

Objective I-D.
Strengthen and integrate programs to monitor and prevent emerging infections 
associated with food/water, new technology, and environmental sources.

Potential sources of human infections change as society evolves. For example, 
microbiologically safe food and potable water, once considered standard 
amenities in most industrialized countries, are threatened by various 
emerging pathogens, even in the United States. As trade and economic 
developments such as the North American Free Trade Agreement take place, the 
globalization of food supplies is likely to have an increasing impact on 
foodborne illnesses. In addition, technologic changes, such as new (invasive) 
medical devices, may increase the risk of nosocomial infections, and changing 
human behavior and demographics may increase exposure to environmental 
sources of infectious agents, such as soil and surface water. These potential 
sources of emerging infections are diverse and cross the lines of various 
scientific disciplines and government agency responsibilities. Coordination 
between CDC and regulatory agencies, such as FDA, the U.S. Department of 
Agriculture (USDA), and the Environmental Protection Agency (EPA), is 
essential because surveillance and investigation of human disease can 
identify the need for new regulations as well as evaluate the effectiveness 
of existing ones.

Activities
i.
Evaluate technologic aspects of food processing and water treatment that may 
promote infectious disease emergence.

Priority areas for increased epidemiologic evaluation and applied research 
will include 1) assessing the impact of technologic changes in food 
production, including pasteurizing eggs, treating chicken carcasses with 
disinfectant, and using automated cooking machinery in restaurants, on 
foodborne disease; 2)determining the risk of meat contamination related to 
various slaughter practices, such as using "distressed animals", slaughtering 
animals on a horizontal surface instead of hanging vertically, or perfusing 
carcasses with cold saline to chill them; 3) assessing the safety of drinking 
water, determining the etiologic agents and impact of waterborne 
gastroenteritis outbreaks, and evaluating the effectiveness of measures, such 
as reverse osmosis filters, to reduce waterborne illness; and 4) developing 
new tools for the rapid and reliable detection of microbial contamination in 
food and water.

In addition, because foodborne and waterborne infections that emerge abroad 
can affect U.S. as well as foreign populations, international efforts are 
also warranted. Improving the microbiologic safety of drinking water and food 
production in developing countries is critical to decreasing morbidity and 
mortality there, particularly in children, and is further needed to ensure 
the safety of the increasing amounts of food imported to the United States 
from these areas. In this regard, additional priorities will be 1) developing 
simple and sustainable measures to improve the safety of drinking water in 
developing countries with techniques such as narrow-necked water vessels or 
point-of-use filtering and disinfection, and 2) improving the hygienic 
standards of restaurants, street vendors, and food wholesalers.

ii.
Assess the impact of modern medical devices on the emergence and prevention 
of nosocomial infections.

Use of invasive medical devices, such as indwelling catheters, often carries 
a risk for infection. Understanding the pathogenesis of these infections, 
evaluating new medical devices, and developing innovative prevention methods 
will be crucial in limiting infections in patients and protecting health care 
workers who use new devices. Applied research in the pathogenesis of 
intravascular catheter infections has already led to the production of a 
silver-ion coated catheter that may reduce infection rates. CDC must work 
closely with FDA and others to identify and evaluate problems associated with 
new medical devices.

iii.
Investigate environmental sources of infection and formulate effective 
control measures.

Many diseases, such as coccidioidomycosis, histoplasmosis, botulism, 
legionellosis, intestinal helminthiasis, and primary amoebic encephalitis, 
are caused by organisms that reside primarily in the soil or water. The 
environmental and climatic phenomena that influence the emergence or 
reemergence of such diseases have not been systematically evaluated. Expanded 
research is needed to better understand these events and enhance our ability 
to predict and control these infections. For example, existing technology, 
such as aerial photography and satellite imaging techniques, has been applied 
to the detection of root lice (grape phylloxera) that is attacking vineyards 
in central California; similar applications are needed for human infections.

The careful assessment of meteorologic events, such as prolonged droughts in 
California (see Box)83 or extensive flooding in the midwestern United States, 
may provide valuable clues about the emergence of infectious disease. In 
situations such as widespread flooding, the ability to rapidly mobilize field 
teams to establish effective surveillance for emerging infections can be 
critical to early recognition and intervention.

Coccidioidomycosis in California
Since 1991, California has experienced large increases in the number of 
reported cases of coccidioidomycosis (valley fever). Symptomatic 
coccidioidomycosis has a wide clinical spectrum, ranging from mild 
influenza-like illness to serious pulmonary disease to widespread 
dissemination. Among persons who become infected, blacks, Filipinos and other 
Asians, Hispanics, and women who acquire the primary infection during the 
later stages of pregnancy are at increased risk for disseminated disease. The 
recent outbreak may have been associated with weather conditions, especially 
a protracted drought followed by occasional heavy rains. The magnitude of the 
outbreak may be partially explained by recent migration of persons previously 
unexposed to Coccidioides immitis into areas of California where 
coccidioidomycosis is endemic. This outbreak illustrates how factors such as 
weather and demographic changes can affect the emergence of public health 
problems from infectious diseases.

Figure.  Reported cases of coccidioidomycosis, by year - California, 1986-1992

In coordination with other groups, CDC will use available data about 
infectious disease threats caused by environmental changes to formulate 
intervention plans. Interventions might include evaluating or modifying a 
planned project, such as a new dam or irrigation project, to reduce the risk 
of altering the environment in a way that might promote emergence of 
infectious diseases. Although environmental impact statements are usually 
required before governmental approval of such projects, the panels that 
review proposals generally do not have infectious disease expertise. 
Participation in this review process by appropriate infectious disease 
experts would help ensure that a project's potential to foster the emergence 
of infectious diseases is considered.

Objective I-E.
Strengthen and integrate programs to monitor, control, and prevent emerging 
vector-borne and zoonotic diseases.

Emerging pathogens maintained in animal reservoirs and transmitted to humans 
through food, arthropod vectors, or other means or are maintained in human 
reservoirs and transmitted from person to person by arthropod vectors pose 
ongoing threats to public health.84  However, effective programs to monitor 
and control these threats are limited or nonexistent. Vector-borne and 
zoonotic diseases overlap extensively, and effective prevention and control 
of infections in both categories require well-integrated, multidisciplinary 
programs and a thorough understanding of the complex ecologic relationship 
between humans, insects, and animals.

Activities
i.
Monitor the distribution of animal reservoirs and vectors associated with 
human disease.

Surveillance systems for important infectious disease vectors and animal 
infections that threaten human health, including studies of the prevalence of 
potential human pathogens in animal populations, are a key component of 
efforts to address emerging vector-borne and zoonotic diseases. The 
surveillance infrastructures discussed previously (Objective IA) may be used 
for this purpose. Priorities for surveillance include potential rodent 
reservoirs of hantavirus; rabies in raccoon populations (Figure 6); 
Cryptosporidium in cattle and wild ruminants such as deer; Echinococcus 
multilocularis in dogs and other canids; the distribution of tick vectors of 
Lyme disease and Rocky Mountain spotted fever; the distribution of mosquito 
vectors of arboviral encephalitides, dengue, and yellow fever (YF) (see Box); 
and the occurrence in humans, ticks, and potential animal reservoirs of 
emerging agents such as Ehrlichia chaffeensis (see Box). The potential use of 
satellite imagery or similar technology to anticipate changes in vectors, 
animals, and the environment that would directly affect the incidence of 
infectious diseases will be assessed.

Monitoring Yellow Fever in Kenya, East Africa
YF is a mosquito-borne viral disease that produces human mortality rates as 
high as 80%. In Africa and South America, many non-human primates maintain 
the infection in so-called sylvatic (jungle) transmission cycles. Humans 
contract the disease when bitten by mosquitoes that have been infected by 
primates. Many human deaths occurred in a 1992-93 outbreak in western Kenya. 
This outbreak was the first documentation of extensive YF transmission in 
that country. Although an emergency vaccination campaign protected close to 
1 million people, a much larger population, living within 150 km of this 
region, will be at risk if transmission continues its apparent southward 
movement. The situation is particularly serious because common household 
mosquitoes like Aedes aegypti can transmit YF and cause massive urban 
epidemics if infected persons are bitten by domestic mosquitoes.

Urban epidemics could occur throughout Kenya and adjacent countries if 
infected persons or mosquitoes are transported to other areas. Therefore, 
ecologic conditions that favor increased sylvatic transmission in eastern 
Africa must be identified. An intensive entomologic/epidemiologic survey 
conducted in March 1993 demonstrated a clear association between YF 
transmission and well-defined vegetational zones. Techniques such as GIS 
analysis would be ideal tools for mapping these vegetational zones and 
predicting shifts in sylvatic transmission patterns, thereby helping target 
areas for vaccination campaigns.

Human Ehrlichiosis, 1985-1992
Human ehrlichiosis is a newly recognized rickettsial disease. The etiologic 
agent, Ehrlichia chaffeensis, was isolated at CDC in 1990. From 1985 through 
1992, 297 infected persons were identified in 27 states. Most patients 
experience fever, rigors, malaise, arthralgias, and nausea. Seven deaths 
have been associated with this disease, including one in a 6-year-old child. 
Complications, which are more likely in persons more than 60 years of age, 
include disseminated intravascular coagulation, renal dysfunction or failure, 
cardiomegaly, seizures, and coma.

Because this emerging disease is not familiar to most clinicians and no 
system for national surveillance exists, its impact on public health both 
here and abroad is probably underestimated. In an active surveillance study 
in Brunswick, Ga., conducted in partnership with the Georgia Department of 
Human Resources and Glynn Brunswick Memorial Hospital, the rate of 
ehrlichiosis (5.3/100,000 population) exceeded by more than sixfold the rate 
of Rocky Mountain spotted fever during the same time period. This high rate 
in conjunction with potentially severe clinical outcome suggests that better 
surveillance for this important and emerging tick-borne infection is urgently 
needed.

In a cooperative project by CDC, USDA, DOD, the University of Florida, and 
other Florida state agencies, GISs and satellite imagery are being used to 
develop models to predict regions of high risk and periods of unusually high 
encephalitis virus activity. These models may provide health officials with 
timely information for implementing early prevention and control strategies 
(personal communication; PB Ladd, Centers for Epidemiology and Animal Health, 
USDA).

ii.
Expand applied research on vector competence, distribution of infectious 
agents among known reservoirs and potential hosts, and ecologic factors 
contributing to the maintenance of vector-borne and zoonotic diseases in 
nature.

Better understanding of animal reservoirs and vectors of infectious agents is 
important in anticipating and controlling emerging infections. For example, 
research to improve understanding of competence and life cycles of tick 
species that harbor Borrelia burgdorferi could lead to control strategies for 
Lyme disease. Similarly, research on Aedes albopictus, which was recently 
introduced into the United States and is a potential vector for the virus 
that causes eastern equine encephalitis, could identify other pathogens that 
use this mosquito as host. In addition, researchers could discover vectors 
for diseases not yet known to be vector-borne. For example, research is 
needed to determine whether arthropod vectors exist for cat scratch disease, 
bacillary angiomatosis, and septicemic disease caused by Rochalimaea species 
and to better define the role of microcrustacean copepods in the environmental 
persistence and transmission of waterborne cholera.

Goal II
Integrate laboratory science and epidemiology to optimize public health 
practice.

Objective II-A.
Expand epidemiologic and prevention effectiveness research.

To effectively address the threats of emerging infections, CDC and its 
partners must build upon traditional strengths in outbreak investigation and 
increase emphasis on development, implementation, and evaluation of 
prevention measures for emerging infectious diseases. These efforts will 
include behavioral risk factor studies, economic analyses of the impact of 
infectious diseases, and evaluations of the cost-effectiveness of new 
interventions and new diagnostic techniques.

Activities
i.
Determine which behaviors prevent or foster emerging infections and how to 
promote or discourage these behaviors.

Human behavior is often a key determinant in the emergence of new diseases, 
and changing human behavior is often the most cost-effective (and sometimes 
the only practical) prevention strategy. Often, critical behaviors that put 
people at risk are initially unknown. Prompt field investigation of outbreaks 
can identify these critical behaviors and lead to effective emergency and 
long-term control measures for the infection. Knowing which behaviors will 
modify risk is a crucial first step in understanding disease transmission; 
however, implementing and sustaining effective behavioral changes may be a 
more difficult challenge. Efforts should focus on determining what message to 
disseminate, how best to communicate the message, and how to effect and 
sustain behavioral changes, recognizing that the approach may vary depending 
on the particular behavior and target group in question (Table 5). Messages 
are often most effective before unsafe behaviors develop; thus, particular 
attention should be given to educational efforts targeted at children and 
adolescents.

Table 5.  Behaviors Shown to Reduce the Risk of Emerging Infections

Cooking hamburger thoroughly to prevent E.coli O157:H7 infections.

Using narrow-necked water containers to reduce the risk of cholera in homes 
without running water in cholera-endemic areas.

Practicing good hygiene with diapered children in child care facilities to 
reduce transmission of rotavirus, Shigella, Giardia, Cryptosporidium, E. coli 
O157:H7, and other agents of diarrheal disease.

Practicing safer sex to prevent the transmission of HIV and other sexually 
transmitted infections.

Eliminating artificial water containers around homes to limit urban habitats 
of dengue- carrying mosquitoes.

ii.
Characterize the impact of well-established and emerging infectious diseases 
on public health in the United States.

Information on length of disability, physician visits, hospitalizations, late 
sequelae, and deaths due to infectious diseases is extremely limited. 
Moreover, current illness classifications underestimate the impact of 
infectious diseases; for example, while ICD-9 classifies injuries together, 
it distributes infectious diseases among several categories, obscuring their 
public health impact. Existing databases of hospital discharge records, 
outpatient visits, and pharmacy records should be analyzed to develop a 
comprehensive general assessment of the impact of infectious diseases. This 
assessment will include critical evaluations of the economic impact of 
emerging and other infections that will allow realistic intervention 
strategies to be developed, on the basis of both health and economic 
indicators.

iii.
Evaluate effectiveness and economic benefit of strategies to prevent emerging 
infectious diseases.

After prevention strategies are formulated and implemented, they must be 
evaluated for effectiveness. For example, studies should assess the extent of 
the implementation and the impact of guidelines issued to prevent infections 
in child care facilities. Further, implementing prevention measures on a 
broad scale requires economic information. Some preventive strategies and 
vaccines are not used because of a perceived lack of cost-effectiveness. 
However, because formal cost-benefit analyses have not been performed for 
most of these options, some effective and available public health options may 
have been overlooked.

iv.
Through an extramural program for emerging infectious disease surveillance, 
epidemiology, and prevention, enhance public health partnerships between CDC, 
health departments, academic centers, and community groups.

In 1973, the CDC extramural infectious disease research program was 
discontinued. Currently, extramural funding is available only for a few 
targeted areas of research, such as HIV/AIDS and Lyme disease. As noted in 
the 1992 IOM report, reestablishing this program would fill gaps in existing 
support for epidemiologic and prevention effectiveness research. Such a 
program would also enhance ties between CDC and the public health community; 
promote career paths; foster alliances among academia, public health, and 
private industry; and establish a national resource for responding to 
emerging infectious diseases.

Objective II-B.
Improve laboratory and epidemiologic techniques for the rapid identification 
of new pathogens and syndromes.

Both nationally and internationally, CDC is often relied upon to characterize 
new infectious disease syndromes, identify etiologic agents, and train others 
to perform these tasks. For example, in recent years, CDC was instrumental 
in finding the causes of Legionnaires' disease, TSS, and HPS and in 
describing the epidemiology of Lassa fever.23,47-50,85,86  CDC's unique capability to 
rapidly apply laboratory and epidemiologic expertise to the identification of 
new or previously unrecognized pathogens is a critical public health resource.

Activities
i.
Establish the means for early, systematic evaluation of newly recognized 
pathogens or syndromes of probable infectious etiology.

Improved information exchange among CDC, state and local health departments, 
and health care providers outlined in Objectives I-A and III-A will increase 
the likelihood that new infectious diseases will be recognized earlier. The 
Sentinel Surveillance Networks and population-based Emerging Infections 
Epidemiology and Prevention Centers, as well as special studies and outbreak 
investigations, can systematically look for evidence of emerging diseases. 
Because of recent experiences with hantavirus, for example, an early priority 
will be to apply newly developed diagnostic techniques in the assessment 
(through active surveillance and focused clinical evaluations) of unexplained 
ARDS.49,50

ii.
Improve laboratory capabilities to identify and characterize emerging 
pathogens.

Essential laboratory activities include histopathologic evaluation of 
specimens, isolation of etiologic agents in culture, and use of modern 
molecular tools to identify agents that cannot be easily cultivated (e.g., 
amplification of 16S ribosomal RNA sequences to identify the etiologic agents 
of Whipples disease and bacillary angiomatosis).87 Also part of this process is 
the ongoing accumulation and maintenance of specimen banks (e.g., serum, 
tissue, and pathogen isolates) which are critical to the comparative analyses 
that must take place to identify and characterize new pathogens (See also 
Objective IV-B, iii).

iii.
Refine and expand the epidemiologic applications of new techniques for 
typing/subtyping emerging pathogens.

Accurate typing (or subtyping) of infectious agents is critical to many 
modern epidemiologic investigations. Phenotypic techniques (e.g., biotyping, 
serotyping, immunoblotting, electrophoretic typing), in addition to the newer 
molecular (genotypic) tools, are becoming increasingly important in tracing 
the spread of disease-causing strains, linking specific strains to point 
sources during outbreaks, and determining the virulence characteristics and 
pathogenesis of agents of emerging infectious diseases.28,88 The molecular tools 
(e.g., restriction endonuclease analysis, pulsed-field gel electrophoresis, 
polymerase chain reaction) are particularly helpful in elucidating the 
clinical and epidemiologic characteristics of uncultured microbial pathogens.87 
The ability to understand the transmission of infectious diseases and the 
virulence characteristics of disease-causing strains is strongly enhanced 
when epidemiologic investigations are complemented by effective subtyping of 
infectious agents.88  For example, molecular epidemiology was instrumental in 
documenting the transmission of HIV in a dentist's practice in Florida.  
Typing/subtyping has been used as an epidemiologic tool to address many other 
infectious disease problems, including the relationship between foods and 
listeriosis,90  and the international spread of an epidemic-causing clone of 
group A N. meningitidis.91,92

The various techniques derived from immunology, biochemistry, and genetics 
for typing or subtyping pathogens are often referred to collectively as 
molecular epidemiology.88 For a typing or subtyping method to improve 
understanding of epidemiologic phenomena, it must be reproducible and 
sufficiently discriminating to discern important epidemiologic relationships 
among different strains of the same species. For example, development of 
effective typing systems for Aspergillus might help identify environmental 
sources of outbreaks of invasive aspergillosis among hospitalized patients. 
New methods must be carefully evaluated according to the criteria of cost and 
ease of application. Subtyping can be a cost-effective public health tool 
when used to detect epidemics quickly and prevent their spread. (see Boxes) 
These techniques were critical in identifying Brazilian purpuric fever (BPF) 
as a new disease. After epidemiologic studies showed that BPF was more likely 
to occur in children with a recent history of conjunctivitis, molecular 
epidemiologic techniques (plasmid profiles, multilocus enzyme electrophoresis 
and ribotyping) demonstrated that the common noninvasive bacterial pathogen, 
H.influenzae biogroup aegyptius, had developed new virulence properties 
resulting in severe and often fatal systemic disease. Some of these 
techniques, such as plasmid profiles, also provide a basis for direct 
identification and description of newly acquired virulence factors.

Diagnostic Assays and Reagents for Detecting Measles Virus
Between 1989 and 1991, more than 50,000 cases of measles, with 11,000 
hospitalizations and 100 measles-associated deaths occurred in the United 
States. This resurgence of measles disease underscored the need for new 
assays to characterize measles virus infections. CDC investigators have 
developed serologic and antigen detection assays to diagnose acute infection 
and demonstrate prior immunity and have used genomic studies to characterize 
the infecting virus. These assays have distinguished measles from outbreaks 
of other rash illnesses, such as rubella or human parvovirus B19; identified 
vaccine-driven antigenic changes in wild measles viruses; demonstrated that 
mild and asymptomatic measles infections may be common in vaccinated 
populations; and distinguished wild-virus disease from vaccine-induced 
disease. These assays are essential to understanding the epidemiology of 
measles in vaccinated populations.

Pulsed-field Gel Electrophoresis of E. coli O157:H7
E. coli O157:H7 strains are difficult to distinguish by classic methods. 
Pulsed-field gel electrophoresis, a newer subtyping method adapted for E. coli 
O157:H7 by CDC investigators, was used during the fast-food restaurant 
hamburger outbreak in western states in January 1993. Using this method, CDC 
investigators demonstrated that strains from patients in four states and from 
the suspect hamburger patties were indistinguishable from each other and 
different from the more than 100 strains in CDC's collection.

Multilocus Enzyme Electrophoresis of Group C N. meningitidis
In the past several years, an increasing number of serogroup C meningococcal 
outbreaks have been reported in the United States. Multilocus enzyme 
electrophoresis, which further differentiates among organisms of the same 
serogroup, has aided in the early identification of outbreaks by establishing 
that isolates from outbreak-associated cases were identical, in contrast to 
cases of sporadic disease, which are usually caused by a variety of strains. 
This information is critical to the formulation of optimal vaccination 
strategies in affected communities.

iv.
Reestablish a core program in human and animal infectious disease pathology.

CDC activities in the evaluation and control of emerging infectious diseases 
require pathology support to identify new or previously unrecognized 
infectious agents as well as to better characterize the pathophysiology and 
anatomic distribution of known agents in humans and in animal models. CDC 
needs to strengthen its capability in human and veterinary infectious disease 
pathology through replenishing expertise at CDC and through enhancing 
partnerships with academic pathologists, offices of medical examiners, and 
others. Infectious disease pathologists have been crucial in elucidating 
emerging infections such as cat scratch disease and bacillary angiomatosis, 
ocular and systemic microsporidiosis, and HPS.

An active program in infectious disease pathology also forms an important 
avenue of communication between CDC scientists and practicing clinical 
pathologists who submit specimens for diagnostic evaluation from patients 
with suspected infectious diseases. These specimens may provide sentinel 
indicators of new pathogens and emerging diseases. Finally, CDC will consider 
establishing cooperative training programs with universities in infectious 
disease pathology, analogous to those under consideration for clinical 
infectious diseases.

Objective II-C.
Ensure timely development, appropriate use, and availability of diagnostic 
tests and reagents.

Efforts will focus on providing well-standardized, economical, high 
performance tests for diseases whose earlier diagnosis would enhance 
treatment and decrease spread, especially diseases for which private industry 
or other institutions are not likely to develop diagnostic tests and reagents.

Activities
i.
Develop and evaluate new diagnostic tools for emerging infections.

Improved tools to diagnose important emerging infections, such as Lyme disease, 
would facilitate earlier treatment, thereby decreasing disability and medical 
costs. Developing, evaluating, and applying tools to diagnose infectious 
diseases that are considered rare or exotic are also needed, as are better 
diagnostic tools capable of distinguishing acute from prior infections.

Since commercially developed diagnostic tools may have uncertain sensitivity 
and specificity, evaluating diagnostic tests is an important public service 
to be carried out by CDC and its partners.

ii.
Maintain diagnostic and reference reagents for the identification of emerging 
pathogens.

CDC proposes to renew its commitment to maintaining diagnostic and reference 
reagents to support outbreak investigations; to provide backup for state, 
local, and clinical laboratories; and to distinguish known infectious diseases 
from new and emerging ones. Partnerships with universities and private 
industry will be helpful in maintaining this capability.

Objective II-D.
Augment rapid response capabilities for vaccine delivery and expand evaluation 
of vaccine efficacy and the cost effectiveness of vaccination programs.

The National Vaccine Program (NVP) coordinates the nation's efforts in the 
development, administration, and evaluation of vaccines. CDC will continue 
to contribute both its laboratory and epidemiologic expertise to this effort, 
including support of the President's Childhood Immunization Initiative.

Activities
i.
Improve rapid response capability and coordinated contingency plans for the 
emergence of new strains of known pathogens, particularly influenza, that 
threaten to cause pandemic disease.

CDC, FDA, NIH, NVP, private industry, and others must work together to address 
new, and possibly more dangerous, strains of known patho ens. Influenza A 
viruses, for example, have undergone major antigenic shifts at unpredictable 
intervals, causing pandemics with high morbidity and mortality. During this 
century, influenza pandemics occurred in 1918, 1957, 1968, and 1977. The 
pandemic of 1918 was the largest in recent history, causing an estimated 
500,000 deaths in the United States and 20 million worldwide. New strains of 
influenza have often emerged in Asia, making virus surveillance on an 
international scale critically important to detecting and monitoring the 
emergence, spread, and impact of new strains (see Box). To lessen the impact 
of the next pandemic, contingency plans developed in 1977, and modified a 
decade ago, will be updated by CDC and others in cooperation with NVP. 
Implementation of these plans will help ensure that the recognition of new 
influenza strains capable of causing pandemic disease is followed by prompt 
reformulation of vaccines and development of recommendations for 
administering vaccines and antiviral drugs.

ii.
Expand the use of CDC specimen banks and diagnostic test development in the 
identification of prospective vaccine components.

CDC is well positioned to identify promising protective antigens for use in 
vaccines because its broad-based surveillance systems and development of 
diagnostic tests have resulted in representative collections of etiologic 
agents and candidate antigens. Once potential antigens are identified by 
state-of-the-art molecular techniques, they can be evaluated in animal models, 
and the most promising ones can be selected for vaccine development. Diseases 
for which new or improved vaccines are needed include Lyme disease, 
meningococcal disease, pneumococcal disease, hepatitis E, RSV, and malaria.

iii.
Evaluate vaccine efficacy and the costs and benefits of vaccination programs 
for emerging infections.

Evaluating the efficacy of and the immunologic response to vaccines against 
diseases such as those caused by S. pneumoniae, H.influenzae type b, and N. 
meningitidis; hepatitis A, hepatitis B, group A rotavirus, and influenza 
viruses; and Plasmodium is a critical step in vaccine development. As new 
vaccines for emerging pathogens are developed, CDC and its partners will need 
to focus on their evaluation, particularly of postlicensure performance.

In addition, available information about vaccine efficacy and duration of 
protection, as well as surveillance information, will be used to develop 
appropriately targeted and cost-effective vaccination strategies (see Box). 
Economic analyses will be an important part of this process.

Vaccination Strategies for Meningococcal Disease
Between 1981 and 1990, 10 outbreaks of group C meningococcal disease were 
identified in the United States.93 In contrast, between 1991 and 1993, eight 
such outbreaks have been reported. Since the disease has a mortality rate of 
about 15% and survivors may have severe complications, including limb 
amputation and neurologic deficits, even small numbers of cases frequently 
create intense public concern and require a rapid response by local and state 
public health authorities. The only effective means of controlling outbreaks 
of this disease are mass vaccination campaigns. However, the decision to 
vaccinate a large population for group C meningococcal disease is difficult.

Current work at CDC to develop specific guidelines for management of group C 
meningococcal disease outbreaks will require analysis of available 
surveillance data to facilitate early detection and cost-benefit analyses of 
potential prevention and control strategies. Long-term management of group C 
outbreaks will require enhanced nationwide surveillance of this disease.

Goal III
Enhance communication of public health information about emerging diseases and 
ensure prompt implementation of prevention strategies.

Objective III-A.
Use diverse communication methods for wider and more effective delivery of 
critical public health messages.

Surveillance data, results of epidemiologic outbreak investigations, 
recommendations developed from risk factor analyses, and other forms of 
public health information relevant to emerging infections are of little value 
unless they reach the appropriate audiences (e.g., public health policy 
makers, health care professionals, the public) in the form of effective public 
health messages. To effectively deliver important public health information, 
CDC and its partners must expand and diversify the mechanisms used to inform 
constituencies. An important first step in this process will be to inventory 
existing informational materials at CDC and elsewhere and to set up a 
clearinghouse for their distribution.

Activities
i.
Develop and distribute educational materials about CDC's emerging infections 
prevention programs to health care professionals.

These materials will include videos for commercial, public, and cable TV 
programs; video and printed materials for use in public health clinics; and 
slide sets or other training materials (e.g., for cholera, HIV/AIDS and other 
STDs, neonatal group B streptococcal infections, hepatitis B, and 
occupationally acquired infections) for use by health care professionals and 
others, who could help expand the dissemination of such information through 
lectures, workshops, and other educational activities. Educational efforts 
should also be directed toward medical schools to ensure that physicians-in-
training understand the importance of surveillance and their responsibility 
for proper notification of public health authorities.

ii.
Enhance media awareness and understanding of CDC's scientific publications on 
emerging infections.

CDC currently produces informational materials that address many important 
public health problems. Media packages for soon-to-be-released publications 
about emerging infections are needed to ensure that the correct messages 
about these new threats are communicated effectively. For example, brief 
video segments will be developed to accompany the distribution of important 
Morbidity and Mortality Weekly Reports (MMWRs) that appeared in the recently 
introduced series, Emerging Infectious Diseases.

CDC staff should be prepared to respond to media or public inquiries, 
particularly during field investigations that command national attention 
(e.g., the recent outbreaks of rodentborne HPS and waterborne 
cryptosporidiosis). Effectively responding to such inquiries will require 
identifying the appropriate individuals for interviews, distributing press 
packets and pamphlets, and providing technical information specialists who 
can respond to public inquiries from segments of society with differing 
levels of medical sophistication.

iii.
Expand distribution of MMWR and other important public health information 
sources.

MMWR is CDC's primary mechanism for rapidly disseminating important public 
health information to a wide range of national and international constituents. 
Because of resource restraints, distribution of free copies of MMWR to medical 
students, general health care practitioners, and others ceased in 1981. 
Although coordination with other medical publications has greatly assisted 
with the dissemination of information contained in MMWR, further broadening 
the distribution of MMWR, in electronic as well as printed format, would 
substantially enhance CDC's ability to provide health professionals with 
critical updates on infectious (and other) diseases.

iv.
Disseminate laboratory information to private and public health laboratories, 
hospitals, and practicing physicians about emerging infectious diseases and 
antimicrobial drug resistance.

The scope of MMWR should be broadened, or a new publication should be created 
to report on important laboratory developments in public health. Regarding 
resistance to antimicrobial drugs, CDC, in coordination with state and local 
health departments, will assist in ensuring that physicians receive better 
and more timely information about which drugs should be used as first-line 
therapy in their locale and which are likely to fail. Also needed to slow the 
pace of development of antimicrobial drug-resistance are more detailed 
guidelines regarding the use of first-line drugs for uncomplicated infections.

v.
Create an accessible and comprehensive U.S. Infectious Disease Database that 
increases awareness of infectious diseases, facilitates their prompt 
recognition, and promotes public health action.

The Infectious Disease Database will synthesize information from the many 
surveillance activities and contain updated information on 1) antimicrobial 
resistance, 2) foodborne infectious diseases, 3) outbreaks of infectious 
diseases, 4) synopses of diseases and syndromes, 5) travelers' health, 6) 
trends in the incidence of infectious diseases, 7) vaccine and antimicrobial 
drug availability, and 8) vaccine guidelines. The database will provide 
information in print and on computer networks and will conform to the 
guidelines and standards established in the CDC Comprehensive Plan for Public 
Health Surveillance (1992 Status Report).

Objective III-B.
Establish the mechanisms and partnerships needed to ensure the rapid and 
effective development and implementation of prevention measures.

In addition to information dissemination, implementation of prevention 
measures includes developing and ensuring the correct use of guidelines, 
providing critical prevention materials to constituencies, and working with 
agencies that have regulatory authority, such as FDA, to remove dangerous 
products from the consumer market (as occurred with certain tampons 
implicated in TSS) or with EPA and USDA/FDA to help ensure microbiologically 
safe water and food, respectively.

Activities
i.
Develop, evaluate, and assist in the implementation of guidelines for 
preventing emerging infectious diseases.

CDC guidelines, such as the Guidelines for Treatment of Sexually Transmitted 
Diseases and Guidelines for Prevention and Control of Nosocomial Infections, 
provide direction for health care professionals who take care of patients or 
develop local regulations. CDC will continue this important activity to review 
available data and develop future guidelines in cooperation with advisory 
groups such as ACIP and the Hospital Infection Control Practices Advisory 
Committee.

 In addition, guidelines analogous to those for preventing nosocomial 
 infections will be developed to prevent infections in other institutional 
 settings, including nursing homes, prisons, and child care centers. For 
 example, CDC has collaborated with FDA to produce videotapes for safe food 
 handling in nursing homes, where foodborne infections are most likely to 
 have serious, or even fatal, results. Similar efforts are needed to promote 
 the appropriate use of antimicrobial drugs and infection control procedures 
 in nursing homes.

FDA and CDC have also collaborated to produce guidelines for the prevention of 
foodborne infections in persons with immunosuppression. This video, entitled 
"Eating Defensively: Food Safety Advice for AIDS Patients", is available through 
the National AIDS Clearinghouse, which has already distributed more than 
10,000 copies. In addition, the formation of community-based health action 
groups made up of state and local health officials, clinicians, and others 
would increase support for recommendations.94

Coordination and ongoing communication with professional organizations that 
issue guidelines or practice parameters to their members (such as the 
American Academy of Pediatrics, the American College of Obstetricians and 
Gynecologists, the American College of Physicians, the American College of 
Emergency Physicians, and the American Academy of Family Physicians) will 
maximize the consistency of guidelines for health care professionals.

ii.

Establish the programs and mechanisms to provide critical prevention materials 
to state and local health departments and other partners and constituents.

Providing prevention materials to state health departments will ensure that 
target groups have ready access to such materials. Examples of these materials 
include brochures about food safety, prevention of infectious diseases in 
child care centers, and travelers' health information; vaccines and other 
biologics; instructions for emergency water treatment; point-of-use water 
treatment devices; and pesticides for emergency vector control. Provision of 
these materials often involves interagency cooperation, such as CDC working 
with EPA to facilitate pesticide approval or waiver processes during public 
health emergencies. This type of cooperation is also needed during periods of 
increased threat from reemerging zoonotic diseases, such as raccoon rabies, 
when innovative means for vaccine delivery may be helpful (see Box).

Raccoon Rabies 
Canine rabies was all but eliminated throughout the United States in the 1950s 
through the use of effective veterinary vaccines; in the 1960s and 1970s, 
wildlife rabies predominated in the approximately 3,000 - 4,000 diagnoses 
annually. During 1990, 1991, and 1992, 4,881, 6,975, and 8,645 cases of 
animal rabies were reported, respectively. Increases were due primarily to 
the epizootic spread of raccoon rabies from the mid-Atlantic region into the 
northeastern United States. Unprecedented numbers are now being reported from 
portions of New England, once largely free from terrestrial rabies. Because 
of their distribution and abundance, particularly in urban areas, raccoons 
are expected to play a major role in the spread of this epizootic to new 
areas for years to come. Although no raccoon-associated cases of human rabies 
have yet been reported, already scarce public health resources are being 
reallocated to prevent this eventuality. Included in this reallocation are 
increased funds for specimen collection, submission, and diagnosis; animal 
control activities; companion animal vaccination; public education; and human 
treatment for suspected rabies exposures. Increasing expenditures for 
postexposure prophylaxis are critically straining existing resources.

New approaches need to be developed to contain this epizootic and prevent 
human infections. Until recently, long-term, cost-effective methods to 
control rabies in free-ranging animals were not available. However, recently, 
new animal rabies vaccines have been introduced that can be incorporated into 
edible baits. Such techniques have already been used to successfully control 
fox rabies in Ontario, Canada, and in 12 European countries and should be 
evaluated for controlling racoon rabies in the United States.

iii.
Establish a coordinated approach for responding to increased demand for (as 
well as shortages and inappropriate use of) drugs and biologics.

A network of specialists, including representatives from FDA, DOD, USDA, NIH, 
and industry, who would systematically exchange information about problems 
related to the availability and use of drugs and biologics is needed. This 
group would evaluate current or anticipated shortages of and increased demand 
for drugs, biologics, or related medical devices. Recruitment of 
professionals with expertise in pharmacoepidemiology would be particularly 
helpful. This group would also initiate necessary actions related to the 
availability of drugs and biologics; such actions include procuring needed 
materials, establishing reserve supplies, identifying target populations, and 
expediting distribution. The provision of primaquine for malaria, 
sulfadiazine for toxoplasmosis, and antitoxin for botulism are recent 
examples of how CDC has responded to such challenges.

Another critical component of this activity will be to address the use of 
antimicrobial drugs by clinicians and their patients. The current crisis in 
antimicrobial resistance cannot be adequately managed without dramatic 
changes in current patterns of antimicrobial drug usage. Clear, readily 
available guidelines for the appropriate use of antibacterial, antiviral, 
antifungal, and antiparasitic medications must be developed and kept current.

Goal IV
Strengthen local, state, and federal public health infrastructures to support 
surveillance and implement prevention and control programs.

Objective IV-A.
Ensure the ready availability of the professional expertise and support 
personnel needed to better understand, monitor, and control emerging 
infections

The results of a recent CSTE survey (June 1993) illustrate the inadequacy of 
personnel resources in state health departments available to detect and to 
respond to emerging infectious diseases in this country.6  Similarly, a task 
force report from the Association of State and Territorial Public Health 
Laboratory Directors (ASTPHLD) voices concerns about the future of public 
health laboratories.95  Rebuilding an infrastructure capable of efficiently 
managing emerging infectious disease threats requires improved support for 
personnel and training at local, state, and federal levels.

The considerable efforts recently applied in investigating HPS are a timely 
reminder of the extensive personnel resources, equipment, supplies, economic 
resources, multidisciplinary coordination, and cooperation among state and 
federal agencies, health care providers, and academia required to rapidly 
link a previously unrecognized human pathogen with a severe illness (see 
Objective I-C). However, this outbreak also illustrates the burden that such 
mobilization places on an infrastructure that has limited surge capacity (see 
Box).

Investigation of Hantavirus Pulmonary Syndrome in the United States, 1993,47-50

The importance of and need for core public health functions are demonstrated 
by the outbreak of disease in 1993 that was first detected in the Southwest 
when a physician there observed an unusual cluster of fatal cases of adult 
respiratory distress syndrome (ARDS) in young adults.

Subsequent investigations involved the cooperative efforts of clinicians, 
laboratorians, ecologists, epidemiologists, and others, representing several 
organizations and agencies including the Navajo Nation Division of Health; 
the Indian Health Service; the New Mexico Department of Health and the Office 
of Medical Investigations; the University of New Mexico School of Medicine; 
state health departments in Arizona, Colorado, and Utah; DOD; and CDC.

Testing done at CDC on specimens collected during these investigations 
included screening for various infectious agents. The diseases and agents 
considered in the differential diagnosis included bacteria (plague, tularemia, 
anthrax, legionellosis, leptospirosis, Mycoplasma, Chlamydia), viruses and 
rickettsia (influenza, parainfluenza, respiratory syncytial virus, 
adenoviruses, cytomegalovirus, arenaviruses, hantaviruses, filoviruses, Q 
fever), fungi (coccidioidomycosis, cryptococcosis, histoplasmosis), and 
protozoa (Pneumocystis). This intensive investigative process revealed 
infection by a previously unrecognized hantavirus. The efforts involved in 
identifying this agent demonstrated the need for maintaining professional 
expertise concerning a broad array of infectious agents, some of which are 
not necessarily considered to be of high public health priority today.

Clinicians have since diagnosed and reported more than 50 cases of HPS (more 
than half fatal) in persons from 15 states: Arizona, California, Colorado, 
Idaho, Indiana, Kansas, Louisiana, Minnesota, Montana, New Mexico, North 
Dakota, Nevada, Oregon, South Dakota, and Texas. Illnesses in more than 70 
persons with ARDS reported from many other state health departments also are 
being investigated by CDC.

Because hantavirus infections have been transmitted in laboratory settings 
and because disease associated with this new strain has been fatal in most 
cases and has no known effective antiviral treatment, much of the laboratory 
work must be carried out in high-level biocontainment facilities.

This is a newly recognized virus and a newly recognized disease. No one yet 
knows the extent of the disease, its geographic and temporal trends, its 
clinical spectrum, or the ecology of the infectious agent in rodent 
reservoirs. Also needed are specific diagnostic tests that can be used by 
public health and clinical laboratories, optimal treatment strategies, and 
public and professional educational programs.

Working with state and local health departments, other federal agencies, 
private health care providers academia, private industry, community 
organizations, and other appropriate groups, CDC is undertaking the following 
activities to address the problem:

National surveillance

Determination of the ecology of hantaviruses in rodents

Expansion of diagnostic capabilities

Definition of pathogenetic mechanisms and immunologic responses to hantavirus 
infections

Assessment of therapeutic regimens in confirmed and suspected cases

Development and evaluation of public and professional educational materials 
and programs

Development and evaluation of rodent control and risk reduction strategies

Activities
i.
Ensure that expertise in rare or unusual, but potentially important, 
infectious diseases is maintained.

CDC is frequently called upon to provide reliable information about the 
diagnosis, clinical management, and control of rare or unusual infectious 
diseases (e.g., botulism; amoebic meningoencephalitis; neurocysticercosis; 
plague; leptospirosis; and Ebola, Marburg, and Lassa viral hemorrhagic fevers). 
To meet this public obligation, CDC must maintain expertise for such diseases 
in the event of their possible reemergence or introduction into new niches in 
the United States and elsewhere. Maintenance of this expertise requires an 
ongoing commitment of resources because the necessary knowledge and skills 
are difficult to acquire and even more difficult (and costly) to replace if 
lost. Such expertise is frequently required at CDC, but can, and often is, 
supplemented by experts at other governmental or academic facilities. 
Innovative "retainer" arrangements would aid access to outside expertise, 
particularly in emergency situations.

ii.
Reestablish a CDC program for state-of-the-art training in diagnostic 
evaluation and testing for emerging infectious diseases.

CDC should ensure that state and selected local health department personnel, 
as well as appropriate public health and university hospital laboratory 
personnel, receive training to support the diagnosis and surveillance of 
selected infectious diseases. The training, which should involve regional 
laboratories, should also address computer and laboratory skills, as well as 
quality assurance and biosafety in laboratories supporting prevention and 
surveillance activities. Such a program would not only serve the purpose of 
training, but also strengthen liaison between public health agencies and 
clinical laboratory personnel to facilitate rapid communication regarding the 
occurrence of unusual syndromes or infectious diseases of unknown cause.

iii.
Establish a public health laboratory fellowship in infectious diseases.

This program, analogous to the EIS for epidemiology training, is needed to 
recruit and retain medical microbiologists for intramural programs and to 
train such persons for employment at, or assignment to, state health and 
other laboratories. CDC has a unique approach to reference diagnostic work, 
molecular epidemiology, and research; a combination of these skills, 
knowledge, and experience will be required to respond to the laboratory 
challenges posed by new agents of infectious diseases, increased virulence of 
known pathogens, increased resistance of pathogens to antimicrobial therapies, 
and the changing susceptibility in human populations.

Objective IV-B.
Make available state-of-the-art physical resources (laboratory space, 
training facilities, equipment) needed to safely and effectively support the 
preceding goals and objectives.

In addition to personnel resources, reference laboratory facilities and 
services are critical to the effective management of emerging infectious 
disease threats.  For instance, the Laboratory Initiatives for the Year 2000, 
a joint venture between ASTPHLD and CDC, has documented the need to enhance 
the diagnostic and analytical capability/capacity of state public health 
laboratories in order to ensure that the Healthy People 2000 objectives are 
met.  Expanded physical resources will be required to attain the goals and 
fulfill the objectives of this plan.

Activities
i.
Equip public health facilities to meet anticipated computer and laboratory 
training needs.

Health departments as well as CDC need improved training facilities and 
equipment. Because many training activities have been phased out over the 
past several years, little physical infrastructure exists for on-site 
training or newer systems for remote teaching, such as teleconferencing. 
Laboratory training emphasizing the identification of emerging pathogens 
will require access to sophisticated equipment and laboratory facilities 
with appropriate levels of biocontainment.

ii.
Ensure that the laboratory space, equipment, and supplies needed to address 
emerging infectious diseases are available.

Improvement and expansion of local and state health department and CDC 
laboratory facilities will be critical to addressing emerging infections. 
Setting priorities for such improvements will require careful evaluation of 
space and equipment needs. Moreover, laboratory capabilities must be 
maintained in a manner that optimizes flexibility and "surge capacity" so that 
unanticipated needs (e.g., responding to new outbreaks such as HPS) can be 
adequately and efficiently addressed. Immediate priorities should include 
improving facilities to deal with infectious agents that require high level 
microbiological safety precautions.

iii.
Expand existing facilities or build new facilities that can adequately and 
safely maintain a specimen bank of etiologic agents and clinical specimens.

A well-maintained and well-catalogued bank of etiologic agents and clinical 
specimens provides an invaluable resource for addressing emerging infectious 
diseases. Well-defined clinical specimens can also be used to evaluate the 
performance characteristics of diagnostic tests under development for 
emerging infectious diseases.

iv.
Upgrade and expand animal care facilities and insectary space.

Animal care facilities must be expanded to meet the increased demand for 
animal models used to elucidate the pathogenesis of emerging pathogens or to 
test new vaccines for emerging or reemerging infectious diseases. Insectaries 
need to be expanded to provide the containment necessary to conduct applied 
research on emerging arboviruses, such as Rift Valley fever virus and Congo 
Crimean hemorrhagic fever virus, and other important vector-borne infectious 
agents.

v.
Furnish the equipment and facilities needed to provide reference diagnostic 
services for emerging infections.

Timely detection of emerging infectious diseases depends on the existence of 
an adequate laboratory diagnostic base, which in turn requires standardized 
reagents (i.e., antisera, antigens, cultures, and epidemiologically well-
characterized control samples). These reagents, as well as reference 
procedures for specialized diagnostic and molecular epidemiologic approaches, 
are usually not produced commercially. CDC should ensure that such reagents 
are made available to all state public health laboratorieseither directly or 
through extramural contacts and cooperative agreements. In a recent survey of 
state laboratories conducted by ASTPHLD, state laboratory directors endorsed 
the need for CDC to enhance its capability to provide reagents and reference 
materials/procedures to state public health laboratories to help them fulfill 
their mission as the primary reference microbiology center in their 
respective state

_____

The Critical Role of Partnerships


The challenge of emerging infections is broad, therefore, an effective 
response will require the efforts of multiple agencies and organizations and
strong ties among public health, clinical, and biomedical research 
professionals. Although CDC maintains primary responsibility for national 
surveillance and rapid investigation of emerging threats, it shares other 
responsibilities with many organizations in regard to research and 
implementation of control measures.

Cooperative efforts between CDC and its partners have helped address such 
infectious disease threats as nosocomial infections, influenza, listeriosis,
streptococcal and pneumococcal disease, ehrlichiosis, and HPS (see Boxes). 
CDC has also cooperated with numerous representatives from academia, 
clinical practice, private industry, health departments, and other federal 
agencies in the development of the National Vaccine Plan and the National 
Action Plan to Combat Multidrug-Resistant Tuberculosis.

Partnerships at the federal level have been helpful in confronting other 
infectious diseases of public health importance in the United States. For 
example, CDC and NIH, working closely with ASTPHLD, developed improved 
diagnostic tests for Lyme disease and various fungal infections. CDC has 
also worked closely with FDA and USDA in controlling emerging foodborne 
illnesses such as listeriosis,90,96 Salmonella enteritidis infection,34 and E. coli
 O157:H7 infection.43,44 Recent CDC collaborations with EPA have been 
instrumental in recognizing and controlling waterborne outbreaks of 
giardiasis and cryptosporidiosis in several states.

In addition, CDC has often joined forces with USDA and DOD to control or 
prevent vector-borne infectious disease threats, such as eastern equine 
encephalitis and St. Louis encephalitis. Such cooperative efforts were used 
successfully to address potential mosquito-borne illness following Hurricane
Andrew in Florida and Louisiana in 1992.97

Clear, well-established lines of communication and responsibility between 
appropriate personnel in federal agencies, such as CDC, NIH, EPA, FDA, USDA, 
DOD, and others, are essential to the development of efficient, cost-
effective prevention and control strategies. Such links help eliminate 
costly duplication of effort and focus limited federal resources on the 
early recognition and timely control of new infectious disease problems.

Effective public health policy results from interaction, cooperation, and 
coordination among a wide range of public and private organizations and 
individuals. Particularly critical to this process are CDC's partnerships 
with state and territorial health departments; other federal agencies; 
professional organizations; academic institutions; private health care 
providers; health maintenance organizations and health alliances; local 
community organizations; private industry; and international partners, 
including WHO and international service organizations and foundations. 
Each of these partners will play an integral role in the cooperative 
efforts required to safeguard the public's health from emerging infectious 
disease threats.

_____

Implementation


This plan provides a comprehensive strategy for the prevention and control 
of emerging infectious diseases. The strategy is based upon the premise that
 it is far less costly, in both human suffering and economic terms, to 
anticipate and prevent infectious diseases than to react with expensive 
treatment or containment measures to unanticipated public health crises.

The plan is a first step in addressing the threats to health in the United 
States posed by emerging infections. The need to rapidly implement this plan
is made more urgent by a number of diseases that pose an immediate danger: 
methicillin-resistant Staphylococcus aureus, a common cause of hospital 
infections, may be developing resistance to vancomycin; penicillin 
resistance is emerging in Streptococcus pneumoniae; cholera is likely to be
introduced into the Caribbean islands from the current pandemic in the 
Southern Hemisphere, and the new strain, V. cholerae O139, is spreading 
rapidly in Asia; changing food industry practices and dietary choices of 
the American people will bring new challenges to providing a diet safe from 
pathogens, such as Salmonella sp. and E. coli O157:H7; and ongoing 
investigations of hantavirus pulmonary syndrome document that the geographic
distribution of this infection is much broader than the desert southwest. 
These infectious disease problems, which have already begun to affect the 
public's health, emphasize the need for expeditiously implementing this plan.

Some of the activities listed in this document are already in the planning 
stages and will be implemented soon. Most will require additional funds and 
personnel. Specific details of many of the proposed activities need further 
development in full cooperation with other federal agencies, state and local
health authorities, academic institutions, professional societies, private 
industry, and others. With this document as a guide and a first step, 
implementation will proceed according to public health needs and resource 
availability. This process will be approached in stages, as a long-term 
endeavor to ensure sustainable impact, and will involve major extramural 
efforts (Table 6).

The Health Security Act of 1993 addresses the need for community-based 
public health strategies in addition to the need for universal health care 
coverage. Prevention of future cases of infectious diseases of multidrug-
resistant TB, influenza, Lyme disease, opportunistic infections, hantavirus 
pulmonary syndrome, cryptosporidiosis, AIDS, and many other emerging 
diseases is a high priority. The health of a community is vital to the health
of individuals and must be maintained through effective public health 
approaches. Through the efforts proposed in this document, the public health
system in the United States will be better prepared to respond to the 
emerging infectious disease threats of the future.

Table 6.  Implementation: High Priorities for 1994-1996

Goal I: Surveillance

Strengthen notifiable disease surveillance at the state and local levels.

Establish two physician-based Sentinel Surveillance Networks to detect and 
monitor emerging diseases, such as unexplained adult respiratory distress 
syndrome, multidrug-resistant pneumococcal disease, and childhood illnesses 
characterized by fever and rash.

Establish four population-based Emerging Infections Epidemiology and 
Prevention Centers to conduct focused epidemiology/prevention projects 
emphasizing foodborne and waterborne infectious diseases and potentially 
vaccine preventable diseases.

Strengthen and link four existing sites for a global consortium to promote 
the detection, monitoring, and investigation of infections emerging 
internationally that could affect the health of Americans.

Goal II: Applied Research

Reestablish an extramural program to support emerging infectious disease 
prevention and control activities, such as evaluating the role of 
prescribing practices in the development of antimicrobial drug-resistant 
pathogens.

Initiate prevention effectiveness studies to assess the impact of food 
preparation guidelines on the incidence of foodborne infections such as 
E. coli O157:H7 and Salmonella enteritidis.

Goal III: Prevention and Control

Develop additional means to deliver laboratory and public health information
informing health professionals about emerging infections and antimicrobial 
drug resistance.

Develop and implement guidelines for the prevention of opportunistic 
infections in immunosuppressed persons.

Goal IV: Infrastructure

Provide state-of-the-art training in diagnostic evaluation and testing 
for medical laboratory personnel to ensure the diagnosis and surveillance of
emerging infections.

Establish a public health laboratory fellowship in infectious diseases that
will train medical microbiologists in public health approaches to diagnosis 
and molecular epidemiology.
_____

Acknowledgments


We gratefully acknowledge the valuable contributions of the following 
colleagues to the development of this plan:  James R. Allen, Henry Anderson,
Larry J. Anderson, Douglas L. Archer, Thomas Arrowsmith-Lowe, William H. 
Bancroft, C.L.R. Bartlett, Nancy H. Bean, David M. Bell, Abram S. Benenson,
John E. Bennett, John V. Bennett, Bobbie A. Berkowitz, Guthrie S. Birkhead,
Paul A. Blake, Coleen A. Boyle, Philip S. Brachman, Windell R. Bradford, A.
D. Brandling-Bennett, Joel G. Breman, Don J. Brenner, Claire V. Broome, 
George T. Bryan, James W. Buehler, Michael J. Burkhart, Jay C. Butler, 
Ronald L. Cada, Carlos C. Campbell, Grant R. Campbell, Roger H. Carlson, 
Gail H. Cassell, Kenneth G. Castro, Willard Cates, Jr., Mary Ann Chiasson, 
Gary G. Clark, Barnett L. Cline, Mitchell L. Cohen, Daniel G. Colley, 
Mary-Paxton D. Colley, E. Mary Cooke, Jose F. Cordero, Jon M. Counts, Nancy
J. Cox, Donald E. Craven, James W. Curran, Mary Ann Danello, Jeffrey P. Davis
, Joe H. Davis, Barbara A. DeBuono, George K. Degnon, Scott D. Deitchman, 
David T. Dennis, Arthur F. DiSalvo, Lynda S. Doll, H. Denny Donnell, D. 
Peter Drotman, Jeffrey S. Duchin, Richard J. Duma, Herbert L. DuPont,
William W. Dyal, Elaine Eaker, Mark L. Eberhard, Paul R. Epstein, Martin S.
Favero, John C. Feeley, Bernard N. Fields, Reginald Finger, David W. 
Fleming, Thomas M. Folks, Christopher Foreman, Willis R. Forrester, Susan W.
Forlenza, Joseph A. Foster, D. Bruce Francy, Linda U. Frank, Phyllis 
Freeman, Kenneth L. Gage, Eugene J. Gangarosa, Lynne S. Garcia, Julia S. 
Garner, G. William Gary, Jr., Howard E. Gary, Kristine Gebbie, Kathleen F. 
Gensheimer, Anne A. Gershon, Noel Gill, Roger I. Glass,  John Glasser, 
Donald A. Goldmann, Robert C. Good, Richard A. Goodman, Michael Gottlieb, 
Steve Gradus, Alan E. Greenberg, Patricia M. Griffin, Donald S. Gromisch, 
Duane J. Gubler, James L. Hadler, Stephen C. Hadler, Robert W. Haley, 
Caroline B. Hall, Scott B. Halstead, Harlyn O. Halvorson, W. Lee Hand, 
George E. Hardy, Jr., William J. Hausler, Mary V. Hearn, D. A. Henderson, 
Kenneth L. Herrmann, Walter J. Hierholzer, Allen W. Hightower, George C. 
Hill, Elvin R. Hilyer, Richard E. Hoffman, Charles H. Hoke, King K. Holmes,
Donald R. Hopkins, John M. Horan, Charles R. Horsburgh, C. James Hospedales,
Robert Howard, Harold W. Jaffe, William R. Jarvis, Suzanne R. Jenkins, Lisa
A. Jackson,  Wanda K. Jones, J. Mehsen Joseph, Dennis D. Juranek, Robert L. 
Kaiser, Martha F. Katz, Arnold F. Kaufmann, Ali S. Khan, Edwin M. Kilbourne,
Lonnie King, Douglas N. Klaucke, Heidi M. Klein, Jane E. Koehler, Edward J.
Koenigsberg, Donald J. Krogstad, John R. LaMontagne, Alexander D. Langmuir, 
Edgar O. Ledbetter, Joshua Lederberg, James W. LeDuc, Harold R. Lentzner, 
Hans O. Lobel, Carlos E. Lopez, Rogelio Lopez, Joseph Z. Losos, Stephen P. 
Luby, John R. Lumpkin, Brian W. J. Mahy, Gerald L. Mandell, R. J. Martin, 
Stanley M. Martin, William J. Martin, William T. Martin, Adolfo 
Martinez-Palomo, William J. Martone, John J. Maupin, C. Glen Mayhall, Joseph
E. McDade, J. Steve McDougal, Louise McFarland, Sara L. McGaughey, J. 
Michael McGinnis, Philip B. Mead, Amy Melnick, Rebecca Meriwether, Tom 
Messenger, Franklin R. Miller, Carl J. Mitchell, Violaine Mitchell, Phyllis 
L. Moir, Arnold S. Monto, Chester G. Moore, Melinda Moore, Patrick S. Moore,
 W. Meade Morgan, Stephen A. Morse, Stephen S. Morse, Ken E. Mott, Robert J.
 Mullan, Frederick A. Murphy, Bernard L. Nahlen, Verla J. Neslund, Ray M. 
Nicola, Stuart L. Nightingale, Gary R. Noble, Pat Nolan, Stanley C. Oaks, 
James G. Olson, Howard W. Ory, Michael T. Osterholm, Stephen M. Ostroff, 
Bradley A. Perkins, Dennis M. Perrotta, Georges Peter, Lyle R. Petersen, 
Larry K. Pickering, Morris E. Potter, Rosemary B. Ramsey, Nancy Rawding, 
William C. Reeves, Russell Regnery, Arthur L. Reingold, I. Paul Reiter, 
Roselyn J. Rice, Jose G. Rigau, John T. Roehrig, Trenton K. Ruebush, Kathy 
H. Rufo, Wilmon R. Rushing, Philip K. Russell, Merle Sande, Jay P. Sanford, 
F. T. Satalowick, Charles P. Schade, Gerald Schochetman, Lawrence B. 
Schonberger, Benjamin Schwartz, Denman H. Scott, Phillip E. Shambra, Janet 
Shoemaker, Robert E. Shope, Bruce Siegel, David R. Smith, Carol D. Snarey, 
Dixie E. Snider, P. Frederick Sparling, Harrison C. Spencer, Robert Steffen,
Gerald V. Stokes, Susan L. Stokes, Al Strating, Donna F. Stroup, Balasubra 
Swaminathan, Ernest T. Takafugi, Robert V. Tauxe, Fred C. Tenover, Steven M.
Teutsch, G. Torrigiani, Louis Trachtman, Dennis W. Trent, Kaye Wachsmuth, 
John W. Ward, MacWilson Warren, Reuben C. Warren, Robert Watkins, Jay D. 
Wenger, Scott F. Wetterhall, F. Stephen Wignall, Mary E. Wilson, Martin S. 
Wolfe, Herbert F. Young, Jane R. Zucker, Larry D. Zyla


---

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Summary of Figures, Tables, and Boxes


Figures
1.  Examples of Emerging and Resurgent Infectious Diseases in the 1990s
2.  Institute of Medicine report, "Emerging Infections: Microbial Threats to
    Health in the United States," National Academy Press, 1992
3.  Emergence of  Foodborne and Waterborne Pathogens  A. E. coli O157:H7   
    B. Cryptosporidium
4.  Spread of Epidemic Cholera Latin America, 19911993
5.  Increasing Incidence of Vancomycin-Resistant Enterococci in U.S. 
    Hospitals by Year National Nosocomial Infections Surveillance System,  
    1989-1993
6.  The Expanding Epizootic of Racoon Rabies Eastern United States, 
    1979-1993
7.  Potential Projects for Emerging Infections Epidemiology and Prevention
    Centers,  United States

Tables
1.  Factors in Emergence
2.  Chronic Manifestations of Infectious Diseases, United States
3.  Proposed Sentinel Surveillance Networks
4.  Examples of Potential Members of a Global Consortium of 
    Epidemiology/Biomedical Research Programs/Centers
5.  Behaviors Shown to Reduce the Risk of Emerging Infections
6.  Implementation: High Priorities for 1994-1996

Boxes

Waterborne Cryptosporidiosis
The National Nosocomial Infection Surveillance (NNIS) System
Sentinel Surveillance for Influenza
Hepatitis Sentinel Counties
Population-based Active Surveillance Project
Coccidioidomycosis in California
Monitoring Yellow Fever in Kenya, East Africa
Human Ehrlichiosis, 1985-1992
Diagnostic Assays and Reagents for Detecting Measles Virus
Pulsed-field Gel Electrophoresis of E. coli O157:H7
Multilocus Enzyme Electrophoresis of Group C  N. meningitidis
Vaccination Strategies for Meningococcal Disease
Racoon Rabies
Investigation of Hantavirus Pulmonary Syndrome in the United States, 1993