Introduction to Public Health Surveillance July 26, 2010

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)

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

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. 2000 Oxford University Press.

Obesity United States, 1987-1998

Types of Surveillance Passive Active Syndromic

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.

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.

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)

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)

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

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)

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

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?

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

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

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

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

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

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.

Disease surveillance: Sentinel Chickens Serology testing Sentinel flock

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

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). 

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 dvanmatr@fmlh.edu

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

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

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.

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

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. 2000 Oxford University Press.

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. 2000 Oxford University Press.

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’

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