1. Introduction to Public Health Surveillance
July 26, 2010

2. Public Health Surveillance
Ongoing, systematic collection, analysis, and interpretation of health-related data
essential to the planning, implementation, and evaluation of public health practice,
closely integrated with the timely dissemination of these data to those responsible for prevention and control.
Centers for Disease Control and Prevention (CDC)

3. Surveillance as a Tool for Community Protection
Initially used for disease control
Now used for:
Communicable and infectious disease
Chronic disease
Injury
Occupational hazards
Other conditions and behaviors

4. Objectives of Public Health Surveillance
Estimate magnitude of the problem
Document distribution and spread of health event
Understand the natural history of a disease
Detect outbreaks or epidemics
Test hypotheses about origin of disease
Evaluate control strategies
Monitor changes in infectious agents
Monitor isolation activities
Detect changes in health practice
Assess the quality of health care
Assess safety of drugs and procedures
Identify research needs and facilitate research
Facilitate planning
Principles and Practice of Public Health Surveillance, Teutsch, SM, Churchill, RE Oxford University Press.

5. Obesity
United States,

6. Types of Surveillance
Passive
Active
Syndromic

7. Passive Surveillance Provider initiated
Laboratories, physicians, or other health care providers regularly report cases of disease to the local or state health department based on a standard case definition of that particular disease.

8. Active Surveillance Health agency initiated
Local or state health departments initiate the collection of specific cases of disease from laboratories, physicians, or other health care providers.

9. Active Surveillance Applications
Outbreak investigations
Contact hospitals and practitioners
Use media to locate cases
Other times when complete case ascertainment is desired (e.g., research study)

11. Syndromic Surveillance
The ongoing, systematic collection, analysis, interpretation, and application of real-time indicators for disease that allow for detection before public health authorities would otherwise identify them.
Indicators
Clinical signs categorized into syndromes
Not a specific diagnosis
Example:
Cough + Sore throat + Fatigue + Fever =
Influenza-Like Illness (ILI)

12. Purposes of surveillance at state and local level
Trigger disease control activities
Accurate diagnosis and treatment
Management of persons exposed to disease
Identify disease outbreaks
Recognize an unusual event
Plan, implement, and evaluate health promotion and disease prevention programs

13. Notifiable Disease Surveillance System
Department of Health Services (DHS), Division of Public Health (DPH)
Wisconsin Electronic Disease Surveillance System (WEDSS) facilitates reporting, investigation, and surveillance
Report de-identified, case-level data to Centers for Disease Control and Prevention (CDC) weekly
National Notifiable Disease Surveillance System (NNDSS), CDC
60 nationally notifiable infectious diseases
List developed and revised by Council of State and Territorial Epidemiologists (CSTE) and CDC
CDC publishes national data in MMWR (Morbidity & Mortality Weekly Report)

14. Legal authority for disease surveillance
Chapter 252 Communicable diseases
Defines powers and duties of Department of Health Services and local health officers
Requires reporting of communicable disease cases and authorizes isolation and quarantine
Authorizes communicable disease prevention and control programs

15. Communicable Disease Reporting
Licensed healthcare personnel
Labs
Health care facilities
Teachers, principals, or nurses in a school or day care center
Any person who knows or suspects a person has a communicable disease
Who Needs to Report?

16. Category I Reportable Diseases
Urgent public health importance
Reported immediately by phone, followed by entering into WEDSS (or 4151)
Includes vaccine preventable diseases, bioterrorism agents, food & waterborne outbreaks
Prompt public health intervention directed at limiting spread in community

17. Category II Reportable Diseases
Less urgent public health importance
Most reportable diseases fall in this category
Reported via WEDSS (or on 4151 or 4243 for STDs) by mail or other means within 72 hours of identification
Public health intervention varies depending on disease

18. Category III Reportable Diseases
HIV and AIDS
Reported directly to state epidemiologist
State distributes to appropriate local health department for follow up

19. Communicable Disease Reporting Resources
EpiNet manual
DPH Communicable Disease website including:
Disease Fact Sheets
Info for healthcare providers
WEDSS (Wisconsin Electronic Disease Surveillance System)
Communicable disease phone contacts
AVR (Analysis, Visualization, & Reporting)
Control of Communicable Diseases Manual

20. Outbreak and unusual event detection
Communicable disease reporting
School, daycare, and worksite absenteeism surveillance
Local surveillance groups and systems
Sentinel surveillance
Special event surveillance
Alerting systems
Other syndromic surveillance systems

21. Sentinel Surveillance for ILI
Wisconsin Sentinel Clinician Program at DPH
Clinical surveillance for influenza
Clinicians report total # of patients and # who meet ILI case definition
fever > 100 degrees with cough or sore throat
Is anyone doing syndromic surveillance with hospital, etc.?
Go to ILI listing for Northern Regiona and Red Cliff and MMC ILI charts.

22. Disease surveillance: Sentinel Chickens
Serology testing
Sentinel flock

23. Alerting Systems Local contact lists Send Word Now Alerting services
Performance measure #6 Local health department can assure 70% of local response partners receive public health emergency communication messages
Send Word Now
Alerting services
Epi-X
CIDRAP

24. Wisconsin Health Information Exchange (WHIE)
Automated, real-time data on ED (emergency department) visits with chief complaint of:
‘fever-flu’ (e.g. ILI) GI
respiratory (e.g. shortness of brief, wheezing etc that don’t fit chief complaint of fever-flu)
‘other’ chief complaints (‘other’ = those that don’t fit in the other categories). 

25. WI-TRAC (Wisconsin Tracking, Resources, Alerts and Communication)
Wisconsin Hospital Emergency Preparedness Program system
Hospital alerting and communication tool
Available to EMS, First Responders, public health, physician offices, law enforcement, fire departments, Dispatch Centers, and Emergency Management directors
Deb Van Matre, WI Trac State System Administrator, at

26. Outbreak and Unusual Events Resources
Communicable disease resources (WEDSS outbreak tab)
Food and Water Borne Disease Outbreak Investigation manual
Wisconsin Hazardous Substances Emergency Events Surveillance (HSEES), DHS
Emergency Preparedness and Response Surveillance, CDC
PHEP (Public Health Emergency Program) plan

27. Monitor health status & disease trends
Disease outcomes
Determinants and risk factors for communicable and non-communicable disease
Examples:
Vaccine coverage
Vaccine-preventable disease morbidity
Screening rates (mammography, cholesterol)
Smoking prevalence
Smoking-related morbidity and mortality

28. Chapter 255 – Chronic Disease, Injuries, MCH
Cancer registry - requires hospitals, physicians, and labs to report cancer or precancerous conditions
Injury prevention - requires DHS to:
Maintain an injury prevention program that includes data collection, surveillance, education, and the promotion of intervention
Assist local health departments and community agencies in local program development and evaluation
MCH:
Identifies responsibilities for infant blindness; newborn hearing screening; birth defect prevention and surveillance
Identifies responsibilities related to sudden infant death syndrome and shaken baby syndrome and impacted babies.

29. Resources for Monitoring Disease Trends
Vital records
Disease registries
Surveys
Administrative data
Other data sources

30. Criteria for choosing priorities for surveillance
Frequency of event (incidence, prevalence, mortality)
Severity (fatality rate, hospitalization rate, disability rate, years of potential life lost, quality adjusted life-years lost)
Cost (direct and indirect)
Preventability
Communicability
Public interest
Principles and Practice of Public Health Surveillance, Teutsch, SM, Churchill, RE Oxford University Press.

31. Steps in planning a Surveillance System
Establish objectives
Develop case definitions
Determine data source or data-collection method
Develop data collection instrument (if nec)
Field-test methods (if nec)
Develop analysis approach
Decide how you will disseminate results
Ensure use of analysis and interpretation
Principles and Practice of Public Health Surveillance, Teutsch, SM, Churchill, RE Oxford University Press.

32. Steps in evaluating a surveillance system
Clearly define the purpose and objective of the system
Describe the operation of the system
Document how the system has been useful
Assess attributes of the system (timely, flexible, representative, cost-effective, complete, simple/easy to apply, acceptable to users, sensitive, specific)
Estimate the cost (direct and indirect)
Timely – get info soon enough to act
Sensitive – detect all cases
Specific – only tracks condition for which it is set up; no ‘false positives’

33. School Surveillance Evaluation Example
Purpose: increases the ability to detect outbreaks in a timely way and enhance understanding of communicable diseases circulating among school-aged children.
Operation: how system was carried out by LPHA and schools (what data is collected, when, how, and by whom); thresholds
Documentation of usefulness: Survey results from schools and LPHAs, data/charts, increased communication between school and LPHA
Assessment of attributes: Was data timely and complete?
Costs: Time of LPHA, school, consortium epidemiologists