[Emerging Infectious Diseases]                                                         
[Volume 4 No. 3 / July - September 1998]

Special Issue

FoodNet and Enter-net: Emerging Surveillance Programs for Foodborne
Diseases

Samantha Yang
Centers for Disease Control and Prevention, Atlanta, Georgia, USA

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The public health challenges of foodborne diseases are changing as a result
of newly identified pathogens and vehicles of transmission, changes in food
production and distribution, and an apparent decline in food safety
awareness. Response to these new challenges requires new surveillance
strategies to monitor the incidence of human illness and provide data for
developing effective prevention strategies.

FoodNet

The Foodborne Diseases Active Surveillance Network (FoodNet), the principal
foodborne disease component of the Centers for Disease Control and
Prevention's (CDC) Emerging Infections Program (EIP), is a collaborative
project with participating EIP sites, the U.S. Department of Agriculture
(USDA), and the U.S. Food and Drug Administration (FDA). To determine more
precisely the incidence of foodborne illness in the United States, FoodNet
was established in five locations (selected counties in California,
Connecticut, and Georgia, and the entire states of Minnesota and Oregon) in
1995 and was expanded to selected counties in Maryland and New York in
1997. The population of these seven FoodNet sites in 1997 was 20.3 million
(7.7% of the U.S. population).

The objectives of FoodNet are to 1) describe the epidemiology of new and
emerging bacterial, parasitic, and viral foodborne diseases of national
importance; 2) more precisely determine the frequency and severity of
foodborne diseases in the United States; and 3) determine the proportion of
foodborne disease caused by eating specific foods. By monitoring foodborne
disease incidence over time, FoodNet will document the effectiveness of new
food safety initiatives, such as the USDA Food and Safety Inspection
Service's Pathogen Reduction and Hazard Analysis and Critical Control
Points (HACCP) Rule, in decreasing the number of cases of foodborne disease
in the United States each year. To address these objectives, FoodNet
conducts active surveillance and related studies: a population survey, a
physician survey, and a case-control study of Escherichia coli O157:H7
infections.

Population Survey

Duc Vugia, California Department of Health, reported the results of the
FoodNet population survey, which was conducted between July 1, 1996, and
June 30, 1997, in selected counties of California, Connecticut, Georgia,
and the entire states of Minnesota and Oregon. This survey provided an
estimate of the prevalence of acute diarrhea and the frequency with which
patients with acute diarrhea sought medical care. In 9,003 interviews, 11%
of persons reported acute diarrhea in the 4 weeks before the interview, 12%
of persons with acute diarrhea called a health-care provider as a result of
this illness, and 8% sought medical care. These data indicate an estimated
1.4 acute diarrheal episodes per person each year in the United States,
with 1% of the population seeking medical care because of acute diarrhea.

Physician Survey

In 1996, to obtain information on stool culturing practices, physicians in
California, Connecticut, Georgia, Minnesota, and Oregon were surveyed.
Results were reported by Thomas Hennessy, CDC. Of the 1,783 physicians
responding to this survey, 44% reported requesting a stool culture from the
most recent patient they remembered seeing who had acute diarrhea. Patient
factors significantly associated with stool culture requests included
bloody stools, a diagnosis of AIDS, diarrhea lasting longer than 3 days,
travel to a developing country, and fever. Stool culture ordering practices
differed by physicians' specialties and geographic site; however, culturing
practices did not differ by payment plan, such as managed care or
fee-for-service. Variability in culturing practices by specialty and
geographic location suggests a need for clinical diagnostic guidelines for
diarrheal illnesses.

Case-Control Study

A case-control study was conducted at FoodNet sites to identify risk
factors for sporadic E. coli O157:H7 infections and to explain variations
in the incidence of E. coli O157:H7 incidence among FoodNet sites. Heidi
Kassenborg, Minnesota Department of Health, presented results from this
study, which was conducted between March 1, 1996, and April 30, 1997, in
selected counties of California, Connecticut, Georgia, and the entire
states of Minnesota and Oregon. Data were obtained from 200 nonoutbreak
case-patients and 380 controls, matched by age and telephone exchange. For
all sites combined, illness was associated with eating pink hamburgers or
pink ground beef and with visiting a farm. Regional variation in beef
processing and in exposure to farms may have contributed to the regional
variability of E. coli O157:H7 infections.

Enter-net
                                   
Funded by the European Commission, Enter-net (formerly Salm-Net) is an
international surveillance system for Salmonella infections
(including data on antibiotic resistance) and E. coli O157 infections.
Microbiologists and epidemiologists responsible for national
laboratory-based surveillance of these pathogens in 15 European countries
form the Enter-net network. Ian Fisher, Communicable Disease Control
Centre, United Kingdom, described Enter-net and highlighted international
outbreaks recognized by the network. Investigations of these outbreaks led
to public health interventions and product recalls in Europe. The
international database of laboratory-confirmed cases of salmonellosis
produced by Enter-net also allows trends in this illness to be observed
over several years. For example, Enter-net is documenting the continuing
problem of Salmonella serotype Enteriditis in western Europe. Enter-net
represents a working model of how focused infection-specific international
surveillance involving key public health professionals can help monitor and
detect international outbreaks of foodborne infection.
[photo]

Emerging Infectious Diseases
National Center for Infectious Diseases
Centers for Disease Control and Prevention
Atlanta, GA

URL: ftp://ftp.cdc.gov/pub/EID/vol4no3/ascii/yang.txt

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