Infectious Disease Epidemiology Surveillance

9/22/00ANN JOLLY 2 Definition n “Ongoing systematic collection, analysis, and interpretation of health data essential to the planning, implementation, and evaluation of public health practice, as well as the timely dissemination to those who need to know” Centers for Disease Control. Comprehensive plan for epidemiologic surveillance. 1986

9/22/00ANN JOLLY 3 Public Health Law - Communicable Disease Control n Reporting and surveillance n Investigation as to source n Examination n Treatment n Isolation/quarantine u with or without judge’s permission u order with or without a warning of an order

9/22/00ANN JOLLY 4 Reporting n Legislation requires the report u name, address, locating and demographics u laboratory data u clinical u treatment u source, contact data n Reportable by; u Laboratory u Health professionals

9/22/00ANN JOLLY 5 Case definition n Defined by government u As part of regulations or Act u includes disease of unusually high numbers u Or disease with unusual manifestations ( high fatality) n Laboratory test component n Clinical n Or both n Ad hoc u Take an inclusive list of 80-90% of first 3-5 presenting cases at least u Be aware that agent may change, and hosts may become immune.

9/22/00ANN JOLLY 6 Emerging and re-emerging infections From MMWR 2003;52:241-8

Network of Singapore cases of SARS as of April 2,2003. ANN JOLLY, 2 APRIL 2003

9/22/00ANN JOLLY 8 Surveillance & Management n Ensure the case, and contacts are properly managed n Monitor the number of cases for unusual changes u risk, manifestation, affected population, geographic area n Consists of : u collection u compilation u analysis u dissemination

9/22/00ANN JOLLY 9 Investigation/contact tracing n Case is treated, educated and questioned about possible exposures n The names of the contacts or sources are reported to public health officials n Then the contacts/sources are located, examined, treated and educated

9/22/00ANN JOLLY 10 Public health data Laboratory test Physician report Laboratory test Physician report Public Heath Department Computer or card file Public health nurse Contact of case Public Health Department Case

9/22/00ANN JOLLY 11 Confidentiality n Disease reporting u individual’s right to privacy is being violated u justification is that it benefits that person u or protects the public health n Contact tracing/ partner notification n Duty to warn

9/22/00ANN JOLLY 12 Tasks 1. Set objectives n Monitor geographic and temporal trends n Investigate n Prevent n Monitor occurrence, without intervention u for health system planning n Monitor for further study

9/22/00ANN JOLLY 13 Tasks 2. Collect data n Disease case reports (notifications) n Laboratory reports n Death certificates n Schools n Sentinel surveillance sites n Animal reports

9/22/00ANN JOLLY 14 Tasks 3. Perform investigations n Source n Route

9/22/00ANN JOLLY 15 Tasks 4. Organise data n Output aggregate data from reports by u time u place u person n Calculate rates, confidence limits n Tabulate, graph

9/22/00ANN JOLLY 16 Tasks 5. Analyse and interpret n Compare current data with past experience, in terms of; n Seasonality n Space n Error, u alpha or beta (statistical) u lab error u calculation u data entry

9/22/00ANN JOLLY 17 Tasks 6. Disseminate n Regional Medical Officer of Health n Provincial Epidemiologist n Chief Medical Health Officer n Infectious disease specialists n Public health units n Public health inspectors

9/22/00ANN JOLLY 18 Tasks 7. Hypothesis formation n Formulate u i.e. waterborne in one municipality n Identify further data to substantiate n Obtain data n Organise n Analyse and interpret n Refute or prove hypothesis

9/22/00ANN JOLLY 19 Tasks 8. Recommend/implement control measures n Establish objectives for control u barriers to infection at any point(s) in host/agent/environment cycle n Recommend control measures n Implement control measures n Evaluate and monitor control measures

9/22/00ANN JOLLY 20 Tasks 9. Distribute findings n Locally n Provincially n Nationally n Internationally

9/22/00ANN JOLLY 21 Tasks 10. Evaluate surveillance system n Data sources u timeliness u accuracy u completeness n Use and relevance of data n Are surveillance objectives being met? n Recommend and implement changes

9/22/00ANN JOLLY 22 References n Teutsch, SM and Churchill, RE, eds. Principles and practice of public health surveillance. Oxford University Press, 1994 n Morbidity and Mortality Weekly Report. Supplement, December Proceedings of the 1992 International Symposium on Public health surveillance. Vol 41. n Thacker SB, Berkelman RL. Public health surveillance in the United States. Epidemiologic Reviews 1988;120: