Incidence And Prevalence assignment paper

Posted: September 17th, 2022

Centers for Disease Control and Prevention Epidemiology Program Office
Case Studies in Applied Epidemiology No. 891-903
Paralytic Illness in Ababo Student’s Guide
Learning Objectives After completing this case study, the participant should be able to:
G Define incidence, prevalence, and case-fatality rate;
G Define surveillance and identify the key features of a surveillance system;
G List the types of information that should be collected on a surveillance case report form;
G List the factors that can account for a change in the reported incidence of a disease;
G Define sensitivity of a surveillance system, and the effect of different case definitions on sensitivity.
This case study was originally developed by Nancy Binkin (EIS ’80) in 1989. The current version was revised and edited by Richard Dicker with input from EIS Summer Course instructors and students over the years
U.S. DEPARTMENT OF HEALTH AND HUMAN SERVICES Public Health Service
 
 
CDC / EIS, 2003: Paralytic Polio in Ababo (891-903) Student’s Guide Page 2
PART I It is the early 1990s. The World Health Organization is planning a program for the global eradication of polio by the year 2000. Likura, a fictitious nation in south-central Africa, may become one of the countries selected to test the effectiveness of WHO’s polio eradication strategies. Unfortunately, little is known about polio in Likura. The Minister of Health therefore assigned the task of assessing the polio situation to a Ministry worker who has recently
returned from an epidemiology course in Atlanta, and who is about to become the District Health Officer in the Ababo District. The Ababo District is a relatively poor, rural district with a single hospital and several health centers. The Ababo District has attempted to conduct surveillance on polio cases and deaths over the past five years. The hospital, health centers, and all health workers are supposed to report such cases to the District Health Officer.
Question 1: What is incidence?
One measure of the polio situation in a community is the prevalence of lameness in
children, since lameness is a common sequela of polio.
Question 2: What is prevalence?
 
 
CDC / EIS, 2003: Paralytic Polio in Ababo (891-903) Student’s Guide Page 3
Question 3a: What data might you use (or collect) to determine the incidence of polio in the population?
Question 3b: What data might you use (or collect) to determine the prevalence of the sequelae of polio (lameness) in the population?
Question 4: What are the key elements included in the definition of public health surveillance?
Question 5: What is the difference between active and passive surveillance systems? Is the Ababo surveillance system for polio passive or active?
 
 
CDC / EIS, 2003: Paralytic Polio in Ababo (891-903) Student’s Guide Page 4
PART II To characterize the incidence of polio over time, the new District Health Officer tabulated the routinely collected surveillance records for the past five years. In Ababo, the operational surveillance case definition for polio is acute onset of flaccid paralysis plus fever. The data are shown in Table 1.
The most recent census was conducted in 1986, when the population of the Ababo District was determined to be 360,000 persons. The population in Ababo is assumed to be growing at a constant rate of 3.8% per year.
Table 1. Polio Morbidity and Mortality, Ababo District, 1986-1990
Year