EPIDEMIOLOGY

Dr khyati boriya

• DEFINATION :• AIMS & OBJECTIVES • EPIDEMIOLOGICAL TRIAD

What is Epidemiology?

• Last’s dictionary gives a detailed definition:• The study of the distribution and

health-related determinants.• states or events in specified

populations.• study to control of health

problems.

• What is Epidemiology?

• Epidemiology is the study of the determinants, distribution, and

• frequency of disease (who gets the disease and why)

• epidemiologists study healthy people

• to determine the difference between those who get exposed and non-exposed people

• epidemiologists study exposed people

• AIMS OF EPIDEMIOLOGY

a) To describe the distribution and magnitude of health and diseases problems in human population.

b) To identify etiological factors in the pathogenesis diseases.

c) To provide the data essential to the planning, implementation and evaluation of services for the prevention, control and treatment of diseases.

OBJECTIVES:

• able to understand the concepts of health dynamics, modes of disease transmission and levels of control and prevention.

• able to compute validity familiar with the brief history of epidemiology, historical epidemiological investigations and interventions.

• to understand design and application of various Epidemiologic methods.

• able to understand and briefly discuss design and interpret public health surveillance.

• able to understand methods of investigations of outbreaks/epidemics.

• able to learn selected applications of epidemiology in health management such as situational analysis, strategic planning, quality assessment and evaluation of health services.

The Epidemiologic Triangle:

• three characteristics• that are examined to study the

cause(s) for disease• in analytic epidemiology

Basic triad of analytical epidemiology

HOST

ENVIRONMENTAGENT

HOST

• personal traits• behaviours• genetic predisposition• immunologic factors

Agents

• Biological (micro-organisms)• Physical (temperature, radiation,

trauma, others)• Chemical (acids, alkalis, poisons,

tobacco, others)• Environmental (nutrients in diet,

allergens, others)

Environment

• Living conditions (housing, crowding, water supply, refuse, sewage, etc)

• Atmosphere / climate• Modes of communication: phenomena in the

environment that bring host and agent together, such as: vector, vehicle, reservoir, etc)

Epidemics occur when ..

host, agent and environmental factorsare not in balance due to new agent, due to change in existing agent (infectivity,pathogenicity, virulence) due to change in number of susceptible in the population due to environmentalchanges that affect transmission of the agent of growth of the agent.