Introduction to Epidemiology for Public Health students

it is a presentation on epidemiology covering the basic concepts.

1. INTRODUCTION TO EPIDEMIOLOGY BY MR. MUGUME ALLAN 1

2. Learning objectives By the end of the lecture, learners should; Define the term Epidemiology. Explain the significance of epidemiology. Discuss basic concepts in Epidemiology. Explain the types of epidemiology. 2

3. 3 Basically speaking Epi = upon (on) Demos = people Ology = the study of Epidemiology = the study of that which falls on people …..

4. What is Epidemiology? Refers to the study of the distribution and determinants of health-related states or events among specified populations, and the application of that study to the control of health problems. 4

5. A Public Health Approach Surveillance Risk Factor Identification Intervention Evaluation Implementation 5 5

6. Purpose of epidemiology Epidemiology helps to identify and describe health problems in a community e.g. prevalence of HIV. It is useful in monitoring continuously over a period of time the change in health of a community. To investigate a disease outbreak, analyze it’s etiology, plan and implement a feasible remedy and evaluate the effect of the remedy on the outbreak. To plan effective health services. To practice surveillance for particular diseases (notifiable). 6

7. Basic concepts in Epidemiology Endemic : disease or condition present among a population at all times . Epidemic/outbreak : disease occurrence among a population that is in excess of what is expected in a given time and place. Pandemic : a disease or condition that spreads across regions (worldwide epidemic ) Sporadic: refers to a disease that occurs infrequently and irregularly. 7

8. Basic concepts in Epidemiology Incidence: the number of new health-related events in a defined population within a specified period of time . Prevalence : the total number of individuals who have a disease divided by the population at risk of having that disease either (a) at a specified time (point prevalence), or (b) over a specified period (period prevalence ). Hyper-endemic: refers to persistent high levels of disease occurrence. 8

9. Types of Epidemiology Descriptive Examines the distribution of a disease in a population, and observes the basic features of its distribution in terms of time , place , and person . Analytical Tests a specific hypothesis about the relationship of a disease to a putative cause, by conducting an epidemiologic study that relates the exposure of interest to the disease of interest. 9

10. The Basic Triad Of Descriptive Epidemiology TIME PLACE PERSON

11. Time Changing or stable? Seasonal variation. Clustered (epidemic) or evenly distributed (endemic)? Point source or propagated. 11

12. Place Geographically restricted or widespread (pandemic)?   Relation to water or food supply.   Multiple clusters or one? 12

13. Person Age Socio-economic status Gender Ethnicity/Race Behavior 13

14. The Basic Triad Of Analytical Epidemiology HOST ENVIRONMENT AGENT

15. Agents Biological, Physical, Chemical Nutrients Poisons Allergens Radiation Physical trauma Microbes Psychological experiences 15

16. Host Factors Genetic endowment Immunologic state Age Personal behavior 16

17. Environment Crowding Atmosphere Modes of communication – phenomena in the environment that bring host and agent together , such as: Vector Vehicle Reservoir 17

18. Descriptive and Analytic Epidemiology Descriptive epidemiology Analytic epidemiology When was the population affected? How was the population affected? Where was the population affected? Why was the population affected? Who was affected? 18

19. QUESTIONS? 19 19

20. INDIVIDUAL ASSIGNMENT For each of the following situations, identify whether it reflects: A. Sporadic disease B. Endemic disease C. Hyper endemic disease D. Pandemic disease E. Epidemic disease 20

21. 1 . 22 cases of legionellosis occurred within 3 weeks among residents of a particular neighborhood (usually 0 or 1 per year) 2 . Average annual incidence was 364 cases of pulmonary tuberculosis per 100,000 population in one area, compared with national average of 134 cases per 100,000 population 3. Over 20 million people worldwide died from influenza in 1918-1919 4 . Single case of histoplasmosis was diagnosed in a community 5 . About 60 cases of gonorrhea are usually reported in this region per week, slightly less than the national average 21

22. ANSWERS 1. E 2. C 3. D 4. A 5. B 22