Public Health 101 Series

Instructor name

Title

Organization 

Introduction to Public Health

Surveillance 

Center for Surveillance, Epidemiology, and Laboratory Services

Division of Scientific Education and Professional Development

Note: This slide set is in the public domain and may be customized as needed by the 

user for informational or educational purposes. Permission from the Centers for 

Disease Control and Prevention is not required, but citation of the source is 

appreciated.
Course Topics

2 

Introduction to Public Health 

Surveillance

1. A Public Health Approach

2. What is Public Health Surveillance?

3. Public Health Surveillance Role and Uses

4. Public Health Surveillance Legal Basis

5. Public Health Surveillance Types and 

Attributes

6. Public Health Surveillance Process
By the end of this session, you will be able to

• define public health surveillance

• describe the goal of public health surveillance

• describe the uses of a public health surveillance system 

• recognize the legal basis for public health surveillance in 

the United States

• compare active and passive public health surveillance

• identify sources of data commonly used for public health 

surveillance

• describe the public health surveillance process

Learning Objectives

3 
A Public Health Approach

Topic 1

4 
A Public Health Approach

Surveillance Risk Factor 

Identification

Intervention

Evaluation Implementation

5 
Public Health Core Sciences

6 
Topic 2

What is Public Health 

Surveillance?

7 
The ongoing, systematic collection, 

analysis, and interpretation of 

health-related data essential to 

planning, implementation, and 

evaluation of public health practice, 

closely integrated with the timely 

dissemination of these data to those 

responsible for prevention and 

control

Public Health Surveillance Defined

Adapted from: Thacker SB, Birkhead GS. Surveillance. In: Gregg, MB, ed. Field epidemiology. Oxford, England: Oxford University Press; 

2008. 8 
analysis

interpretation

collection

dissemination

ongoing

systematic

health-related data

linked to public health practice

Public Health Surveillance Keywords

9 
Goal of Public Health Surveillance

Provide information that can be used for health 

action by public health personnel, government 

leaders, and the public to guide public health 

policy and programs

Smith PF, Hadler JL, Stanbury M, et al. Blueprint version 2.0: updating public health surveillance for the 21st century. J Public Health 

Manag Pract 2013;19:231–9. 10
A. systemic, short-term 

B. ongoing, systemic 

 C. ongoing, systematic 

 

D. methodical, ongoing

Public Health Surveillance is the ________, __________ 

collection, analysis, and interpretation of healthrelated data.

Knowledge Check

11
What is the goal of public health surveillance?

 

Knowledge Check

12

A. To give public health personnel policies to regulate

B. To provide information to be used for public

 health action

C. To guide Congress in enacting public health laws

D. To keep the public aware of new diseases
Topic 3

Public Health Surveillance

Role and Uses

13
• Identify patients and their contacts for treatment and 

intervention 

• Detect epidemics, health problems, changes in health 

behaviors 

• Estimate magnitude and scope of health problems

• Measure trends and characterize disease

• Monitor changes in infectious and environmental agents

• Assess effectiveness of programs and control measures

• Develop hypotheses and stimulate research

Uses of Public Health Surveillance

14
Whooping Cough Kills Five in California; 

State Declares an Epidemic

Number of Rare E. Coli Cases 

In U.S. Rose Last Year

Increase Seen in Deaths from

 Pneumonia and Flu 

Percentage of New Yorkers Lighting Up 

is Down to 14%

New CDC Report Shows Adult Obesity 

Growing or Holding Steady in All States

15

Public Health Headlines
Number of Rare E. Coli Cases 

In U.S. Rose Last Year

16

Neuman W. Number of Rare E. Coli Cases In U.S. Rose Last Year. The New York Times. June 7, 2011. http://www.nytimes.com. 

Accessed July 8, 2014.
Identify the surveillance uses that can be linked to 

the New York Times E. coli article.

A. Measure trends of a particular disease

B. Estimate the magnitude of the problem

C. Monitor changes in infectious and environmental

 agents

D. Assess effectiveness of programs and control 

 measures

E. All of the above

Knowledge Check

17
Topic 4

Public Health Surveillance

Legal Basis

18
States have authority based on

the U.S. Constitution 

• General welfare clause

• Interstate commerce clause 

CDC responds when

• disease or condition has interstate 

implications

• invited by a state 

Legal Authority for Conducting 

Public Health Surveillance

19
State-Based Notifiable Disease

Surveillance Systems

• Mandated by state law or regulation

• Health care providers, hospitals, and laboratories are 

required to report cases to the local health 

department (LHD)

• The LHD is usually responsible for case investigation 

and action

• The LHD forwards the disease report to the state 

health department

• The state health department assists the LHD as 

needed 

20
The purpose and legal basis for public health 

surveillance is granted by which U.S. document?

A. Bill of Rights

B. Declaration of Independence

C. U.S. Constitution

D. 1812 Treaty of Public Health

Knowledge Check

21
CDC must be invited by a state before conducting 

public health surveillance. 

A. True

B. False 

Knowledge Check

22
Topic 5

Public Health Surveillance

Types and Attributes

23
Passive Surveillance Active Surveillance

• Diseases are reported 

by health care providers

• Simple and inexpensive

• Limited by incompleteness

of reporting and variability

of quality

• Health agencies contact 

health providers seeking 

reports

• Ensures more complete 

reporting of conditions

• Used in conjunction 

with specific epidemiologic 

investigation

Types of Public Health Surveillance

24
Reporting of health events by health professionals who 

are selected to represent a geographic area or a 

specific reporting group

Can be active or passive

Sentinel Surveillance

Focuses on one or more symptoms rather than a 

physician-diagnosed or laboratory-confirmed disease

Syndromic Surveillance

Other Types of Public Health Surveillance

25
Surveillance System Attributes

26

Attribute Question It Answers

Usefulness How useful is the system in 

accomplishing its objectives?

Data quality

How reliable are the available data? 

How complete and accurate are data 

fields in the reports received by the 

system? 

Timeliness How quickly are reports received?

Flexibility How quickly can the system adapt to 

changes? 

Simplicity How easy is the system’s operation?
Surveillance System Attributes

27

Attribute Question It Answers

Stability 

Does the surveillance system work 

well? 

Does it break down often?

Sensitivity 

How well does it capture the 

intended cases?

Predictive value

positive

How many of the reported cases 

meet the case definition?

Representativeness 

How good is the system at 

representing the population under 

surveillance? 

Acceptability How easy is the system’s operation?
Knowledge Check

The New York State Department of Health contacts 

the health providers in District A every Friday to obtain 

the number of patients examined with Influenza. What 

type of surveillance is this?

A. Passive

B. Active

28
Topic 6

29

Public Health Surveillance 

Process
Before collecting data, decide

on the overarching goal

of the system

Surveillance Process

Data 

Collection

Data Analysis

Data 

Interpretation 

Data 

Dissemination 

Link to Action

30
Data Sources for Public Health Surveillance

• Reported diseases or syndromes

• Electronic health records (e.g., hospital discharge 

data)

• Vital records (e.g., birth and death certificates)

• Registries (e.g., cancer, immunization)

• Surveys (e.g., National Health and Nutrition 

Examination Survey [NHANES])

31
Nationally Notifiable Disease

Surveillance System (NNDSS)

Many diseases on a state 

list are also nationally 

notifiable 

32
Reporting to WHO is required for cases of

Internationally Notifiable Diseases

33

• Smallpox

• Poliomyelitis (wild type)

• Human influenza caused by 

any new subtype

• Severe acute respiratory 

syndrome (SARS)
• Who will analyze the data?

• What methodology will they 

use?

• How often will they analyze 

the data?

Surveillance Data Analysis

Data 

Collection

Data Analysis

Data 

Interpretation 

Data 

Dissemination 

Link to Action

34
Patients Hospitalized with West Nile

Virus Infection, by Week, New York, 1999

Week of illness onset

Nash D, Mostashari F, Fine A, et al. Outbreak of West Nile virus infection in the New York City area in 1999. 

N Engl J Med. 2001;344:1807–14. 35
North Queens 

Serosurvey Area

Surveillance Data Analysis by Place

Laboratory-Confirmed WNV Human Cases — August–September 1999

Map Courtesy of the New York City Department of Health and Mental Hygiene

36
Characteristic No. of Patients (%) Population at Risk

Rate of Infection per 

Million Population

Age (years)

0–19 2 (3) 2,324,081 0.9

20–29 1 (2) 1,553,981 0.6

30–39 3 (5) 1,549,111 1.9

40–49 1 (2) 1,177,190 0.8

50–59 9 (15) 867,331 10.4

60–69 12 (22) 814,838 16.0

70–79 18 (31) 534,785 33.7

≥80 12 (20) 281,054 42.7

Age category (years)

≥50 52 (88) 2,498,008 20.8

<50 7 (12) 6,604,363 1.1

Sex

Male 31 (53) 4,289,988 7.2

Female 28 (47) 4,812,383 5.8

Race

White 41 (69) 5,983,901 6.9

Nonwhite 9 (15) 3,118,470 2.9

Unknown 9 (15) -- --

Borough or county of residence

New York City

Brooklyn (Kings) 3 (5) 2,300,664 1.3

Bronx 9 (15) 1,203,789 7.5

Manhattan 1 (2) 1,487,536 0.7

Queens 32 (54) 1,951,599 16.4

Staten Island (Richmond) 0 379,999 0.0

New York State

Nassau 6 (10) 1,287,348 4.7

Westchester 8 (14) 847,866 9.1

Data Analysis by Person

Do you notice any patterns in the rates? 

Nash D, Mostashari F, Fine A, et al. Outbreak of West Nile virus infection in the New York City area in 1999. N Engl 37

J Med. 2001;344:1807–14.

Demographics for Persons Hospitalized for WNV and Population Rates of Infection
Data interpretation 

is closely coupled 

with data analysis

Surveillance Data Interpretation

Data 

Collection

Data Analysis

Data 

Interpretation 

Data 

Dissemination 

Link to Action

38
What Can Account for an 

Apparent Increase in Cases? Number of Rare E. Coli Cases 

In U.S. Rose Last Year

39

Neuman, W. Rare E. Coli Cases Rose In the U.S. Last Year. New York Times June 7, 2011. http://www.nytimes.com. Accessed 

July 9, 2014.
• Health agency newsletters, 

bulletins, or alerts 

• Surveillance summaries and 

reports

• Medical and epidemiologic 

journal articles 

• Press releases and social 

media 

Data Dissemination

Data 

Collection

Data Analysis

Data 

Interpretation 

Data 

Dissemination 

Link to Action

40
• Public health practitioners

• Clinicians and other health care providers

• Policy and other decision makers

• Community organizations

• The general public

Data Dissemination Target Audiences

41
Public health surveillance 

should always have a 

link to action

Surveillance Link to Action

Data 

Collection

Data Analysis

Data 

Interpretation 

Data 

Dissemination 

Link to Action

42
Link to Action

Monitor trends and patterns in disease, risk factors, and agents

43

Source: Centers for Disease Control and Prevention (CDC). National Notifiable Diseases Surveillance System and Supplemental 

Pertussis Surveillance System and 1922-1949, passive reports to the US Public Health Service. Atlanta, GA: US Department of 

Health and Human Services, CDC. Available at: http://www.cdc.gov/pertussis/images/incidence-graph.jpg.

Pertussis (Whooping Cough) Cases, by Year — United States, 1922–2000
Choose the option that is NOT a part of the public 

health surveillance process. 

A. Data dissemination

B. Data storage

C. Link to action

D. Data collection

Knowledge Check

44
In data interpretation, by identifying the ___________, 

 ________, and _____________, you can more easily 

determine how and why the health event occurred.

A. disease, risk, occurrence

B. person, protocol, risk

C. person, place, time

D. risk, protocol, disease

Knowledge Check

45
Choose the option that is NOT a source of data used 

for public health surveillance. 

A. Administrative data systems

B. Vital records

C. Newspaper articles

D. Disease notifications

Knowledge Check

46
• Describe the burden of or potential for disease

• Monitor trends and patterns in disease, risk factors, and 

agents 

• Detect sudden changes in disease occurrence and 

distribution 

• Provide data for programs, policies, and priorities

• Evaluate prevention and control efforts

Public Health Surveillance-Based Action

47
Foege WH, Hogan RC, Newton LH. Surveillance projects for selected diseases. Int J Epidemiol 1976;5:29–37. 48

Photo: Kay Hinton, Emory University

“The reason for collecting, 

analyzing, and disseminating 

information on a disease is to 

control that disease. Collection 

and analysis should not be 

allowed to consume resources if 

action does not follow.” 

 —William Foege, 1976
During this session, you learned to

• define public health surveillance

• describe the goal of public health surveillance

• describe the uses of public health surveillance system 

• recognize the legal basis for public health surveillance

in the United States

• compare active and passive public health surveillance

• identify sources of data commonly used for public health 

surveillance

• describe the public health surveillance process

Course Summary

49
QUESTIONS?

50
• Smith PF, Hadler JL, Stanbury M, et al. Blueprint version 2.0: updating public 

health surveillance for the 21st century. J Public Health Manag Pract 

2013;19:231–9. 

• Centers for Disease Control and Prevention. CDC’s vision for public health 

surveillance in the 21st century. Morb Mortal Wkly Rep 2012;61(Suppl, July 27, 

2012):1–40.

• Centers for Disease Control and Prevention (CDC). Principles of epidemiology 

in public health practice [Self-Study Course]. 3rd ed. Atlanta, GA: US 

Department of Health and Human Services, CDC; 2006. 

http://www.cdc.gov/osels/scientific_edu/ss1978/SS1978.pdf.

• Lee LM, Teutsch SM, Thacker SB, St. Louis M, Eds. Principles and practice of 

public health surveillance. 3rd ed. Oxford, England: Oxford University Press; 

2010.

• Thacker SB, Birkhead GS. Surveillance. In: Gregg, MB, ed. Field epidemiology. 

Oxford, England: Oxford University Press; 2008.

• Langmuir AD. The surveillance of communicable diseases of national 

importance. New Engl J Med 1963;258:182–92. 

• Foege WH, Hogan RC, Newton LH. Surveillance projects for selected diseases. 

Int J Epidemiol 1976;5:29–37. 

Resources and Additional Reading

51
• Centers for Disease Control and Prevention. Updated guidelines for evaluating 

public health surveillance systems: recommendations from the Guidelines 

Working Group. MMWR Recommend Rep 2001;50(No. RR-13).

• Centers for Disease Control and Prevention (CDC). Surveillance resource 

center. Atlanta, GA: US Department of Health and Human Services, CDC; 2013. 

http://www.cdc.gov/surveillancepractice/.

• Nash D, Mostashari F, Fine A, et al. Outbreak of West Nile virus infection in the 

New York City area in 1999. N Engl J Med. 2001;344:1807–14.

• Török TJ, Tauxe RV, Wise RP, et al. A large community outbreak of salmonellosis 

caused by intentional contamination of restaurant salad bars. JAMA 

1997;278:389–95. 

• Kim M, Berger D, Matte T. Diabetes in New York City: public health burden and 

disparities. New York: New York City Department of Health and Mental 

Hygiene; 2006. 

http://www.nyc.gov/html/doh/downloads/pdf/epi/diabetes_chart_book.pdf.

• Swerdlow DL, Woodruff BA, Brady RC, et al. A waterborne outbreak in Missouri 

of Escherichia coli O157:H7 associated with bloody diarrhea and death. Ann 

Intern Med 1992;117:812–9. 

Resources and Additional Reading

52
BONUS SLIDES

53
Link to Action

Provide data for programs, policies, and priorities

1994–95 1996–97 

% Reporting diabetes 

Year 

1998–99 2000–01 2002 2003 2004 

Kim M, Berger D, Matte T. Diabetes in New York City: public health burden and disparities. New York: New York City Department of 

Health and Mental Hygiene; 2006. http://www.nyc.gov/html/doh/downloads/pdf/epi/diabetes_chart_book.pdf. 54
Link to Action

Evaluate prevention and control efforts

No. of cases

Swerdlow DL, Woodruff BA, Brady RC, et al. A waterborne outbreak in Missouri of Escherichia coli O157:H7 associated with bloody

diarrhea and death. Ann Intern Med 1992;117:812–9. 

Water

system 

flushed

Boil-water 

order

Date of onset

55
Link to Action

Evaluate prevention and control efforts (continued) 

No. of cases

Swerdlow DL, Woodruff BA, Brady RC, et al. A waterborne outbreak in Missouri of Escherichia coli O157:H7 associated with bloody

diarrhea and death. Ann Intern Med 1992;117:812–9.

Water

system 

flushed

Boil-water 

order

Chlorine 

added

Date of onset

56
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not imply endorsement by the Division of Scientific Education and Professional 

Development, Center for Surveillance, Epidemiology, and Laboratory Services, 

Centers for Disease Control and Prevention, the Public Health Service, or the U.S. 

Department of Health and Human Services.

The findings and conclusions in this course are those of the authors and do not 

necessarily represent the official position of the Centers for Disease Control and 

Prevention.

Disclaimers 

57
For more information, please contact the Centers for Disease Control and Prevention

1600 Clifton Road NE, Atlanta, GA 30333

Telephone: 1-800-CDC-INFO (232-4636)/TTY: 1-888-232-6348

Visit: http://www.cdc.gov | Contact CDC at: 1-800-CDC-INFO or http://www.cdc.gov/info

The findings and conclusions in this course are those of the authors and do not necessarily represent the official position of the 

Centers for Disease Control and Prevention.

Center for Surveillance, Epidemiology, and Laboratory Services

Division of Scientific Education and Professional Development