Epidemiology is the study of how diseases are distributed in populations and the factors that influence this. It examines why some people develop illnesses and others do not. Epidemiology helps public health officials understand health problems in communities and find ways to control and prevent diseases. The history of epidemiology shows how early physicians like Hippocrates linked environmental factors to health, and later scientists such as John Snow used epidemiological findings to control outbreaks. Modern epidemiology involves counting cases, measuring populations, analyzing health problems, applying solutions, and evaluating their effectiveness. It provides insights used in public health programs and patient care.

1. Epidemiology
“I keep six honest men; they taught me all I know.
Their names are what, why, when, how, where,
who.” Dr Naveen Phuyal
MBBS, MD

2. Objectives of this class
• Describe the concept of epidemiology
• Historical development of epidemiology
• Practice and use of epidemiology in health
management and patient care.

3. Type of class
• Interactive class
• You can ask questions in between or at the
end
• Assignments

4. Books to read

5. Concept of epidemiology

6. What is Epidemiology?
I hate definitions.
- Benjamin Disraeli
(British Prime Minister)

7. What is epidemiology?
• The study of how the disease is distributed in
Populations.
• The factors that determine or influence this
distribution.
• Why does a disease develop in some people
and not in others?

8. Understanding Epidemiology
• Illness and ill health are not randomly
distributed in human populations.
• Each of us have certain characteristics that
predispose us to, or protect us against, a
variety of different diseases.

9. Understanding Epidemiology
• Epidemiology is the basic science of Public
Health and Preventive Medicine.
• Epidemiology is a scientific foundation for the
practice of public health.
• Epi- upon, demos- people

10. Understanding epidemiology
• Epidemiology is a very special field.
• Every standard medical text books have
paragraph in Epidemiology
• Epidemiology is a pervasive science and a
basic tool for understanding and practice of all
specialties of medicine.

11. Understanding epidemiology involves
two things
• Knowledge of principles of medicine
• Knowledge of basic principles of
Epidemiology.

12. Essay on Malaria
• Malaria is caused by a parasite called Plasmodium.
• It is transmitted by bite of female anopheles
mosquito. It manifests as acute febrile illness with
chills and rigors.
• In our country 2-3 in 10000 people are likely to get
malaria every year.
• It is more common among children, poor people,
foreigners, immunocompromised people.
• It is common in Terai region, urban slums but not in
hilly areas.

13. Essay on Malaria
• Malaria can be prevented by spraying insecticides on
water collections and on the walls of our houses.
• It can be diagnosed by a simple blood test and can be
treated effectively by oral Chloroquin and Primaquin.

14. The above facets put together is called as “Epidemiology”

15. • Epidemiology is that branch of medicine
which answers the issues related to human
health problems and diseases the magnitude
that they pose, their distribution acc. to time
place and person, and various factors which
determines the causation, risk, prognosis,
management and prevention of diseases.

16. Definitions
• A branch of medical science which treats epidemics (
Parkin, 1873)
• The science of mass phenomena of infectious diseases
( Frost, 1927)
• The study of disease, any disease, as a mass
phenomenon ( Greenwood, 1934)
• The study of distribution and determinants of disease
frequency in man ( Macmohan, 1960)

17. 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 control of health problems.”
--- John. M Last ( 1988)

18. • Although there is no single definitions, three
components are common:
• Study of disease frequency
• Study of disease distribution
• Study of disease determinants

19. Historical development of Epidemiology

21. History
• 400 BC Hippocrates: Occurrence of human diseases
to the environment “ On Airs, Waters and Places”

22. Assignment

23. History
• Control of communicable disease and public
health through quarrantine and isolation,
ideas about disease transmission and
microbiology.
• Johann Peter Frank systematized and codified
many rules for personal and communal
behavior in the eighteenth century.

24. Assignment
• Willam Farr in 19th Century
• John Snow: 1850

25. Assignment

26. Assignment
• Case control study on smoking and lung
Cancer by Sir Richard Doll and Sir AB Hill

27. What does the brief history about
epidemiology teach us?
• Community and environment influence of
health of humans
• Knowing how a disease is transmitted permits
us to prevent and control it even if we do not
know the cause.

28. What does the brief history about
epidemiology teach us?
• Simplest information about vital events, illness
and populations can detect and analyze
epidemiological problems.
• Epidemiology can help find, investigate,
analyze, control, and prevent a wide range of
health problems.

29. Practice and use of epidemiology in health
management and patient care.

30. Practice of epidemiology
• The basic operation of epidemiologist is to
count cases and measure the population in
which they arise.
• The practice of epidemiology is a scientific
process that detects, investigates and analyzes
health problems followed by applying this
information to the control and prevention of
these problem.

31. Practice of epidemiology
• The findings of analysis are linked to health
policies which prevent and control the
problem using health programmes
• This is followed by evaluation of control and
prevention

32. Uses of epidemiology

33. Objectives of this class
• Describe the concept of Epidemiology
• Historical development of Epidemiology
• Practice and use of epidemiology in health
management and patient care.

34. Thank You