EPIDEMIOLOGY

Lecture 1: Introduction

Lecture Objectives

By the end of this lecture, the student will be able to:

1. Understand the importance of epidemiology in medical sciences by knowing some of its achievements.

2. Define epidemiology.3. Describe the epidemiologic approach.4. Enumerate the aims of epidemiology.

John

Sno

w

Chol

era

The contribution of John Snow

Cholera is spread by contaminated water

(1850)

Vibrio cholerae hadn’t yet been

discovered

Many years before Louis Pasteur’s

“Germ theory of disease” (1873)

How was Snow able to conclude that Cholera is spread by contaminated

water?

Some important achievements in Epidemiology

1. Smallpox Eradication

2. Methyl Mercury poisoning

3. Rheumatic fever and RHD

Penicillin

PovertyPoor housingOvercrowding

4. Tobacco use, Asbestos and Lung cancer

5. The HIV/AIDS Epidemic

The definition of epidemiology

The study of the distribution and determinants of health-related states or events in specified populations, and the application of this study to the prevention and control of health problems

Observation, Surveillance, Hypothesis testing, ExperimentTime, Place, Person

Biological, Chemical, Social, Economic, Behavioural etc.

Entire populations, Groups of populations (Occupation, Residence, Gender, Education etc.)

The Epidemiological Approach

1 Asking Questions

WHAT? WHERE? WHEN? WH0? HOW? WHY?

2 Making Comparisons

Aims of Epidemiology

• Describe distribution and magnitude of health and disease problems in human populations.

• Identify etiological factors in disease pathogenesis.

• Provide data essential to planning, implementation and evaluation of services for the prevention, control and treatment of disease and to the setting up of priorities among those services.

Sir Richard Doll(1912-2005)