The document provides definitions and historical background information about epidemiology. It defines epidemiology as the study of disease distribution, frequency, and determinants in human populations in order to control health problems. Some key points mentioned include: - Epidemiology studies entire populations while clinical medicine focuses on individual patients. - Important figures in the history of epidemiology include Hippocrates, John Snow, and William Bugg who conducted early studies of cholera, typhoid, and other diseases. - Epidemiology aims to reduce disease burden and promote population health through describing disease patterns, identifying causes, and informing prevention and control efforts.

1. INDIAN DENTAL ACADEMY
Leader in continuing Dental Education

2. At the end of the class

3. At the end of the class

4. At the end of the class

5. Definitions
HISTORICAL
DEVELOPMENTS

6. EPIDEMIOLOGY
Vs
Clinical Medicine

7. Definitions

8. Definition of epidemiology
• Greek word – epi : on
demos : common people
logy : study
• Putting these pieces together yields the
following definition ,
• “the study of that which falls on the
common people”.

9. Definition
It is the study
ofthe distribution
and determinants
of
health-related states or events
in
specified populations,
and the application ofthis study to the
controlofhealth problems.”
- JOHN. M. LAST

10. The study of the
distribution and determinants of
disease frequencies .
- MACMOHAN &PUGH
Definition

11. Definition of epidemiology
•The study of distribution and
determinants of disease
frequency in human population
and application of this study to
control health problems .

12. Key words in the definition
• Population
• Disease frequency
• Disease distribution
• Disease determinants
• Disease control / control of health
problems

13. Population
• It is combination of two words :
Latin - Populous = people
English – Tion = result of action
It refers to group of people with common
characteristics such as place of
residence ,gender ,age or certain use of
medical services .

14. Disease frequency
Ease = comfort ,
absence of difficult , freedom from
problem .
Dis = not
• DISEASE

15. • Frequency refers to how often a disease
arise in a population.
• Tools for measuring frequency are :
INCIDENCE
PREVALENCE
Disease frequency

16. Disease distribution
• It means
• who is getting the disease,
(males , females, children or adults )
where it is occurring
(urban or rural )
how it is changing over
( whether there is decrease or increase
in disease over time span)

17. Disease determinant
• Determinants are the factors that bring
about changes in person’s health.
• These determinants ,
• either cause a healthy individual to
become sick or a sick person healthy.
• Individual determinants
• Environmental and societal
determinants .

18. Disease determinant
• Individual determinants :
 Genetic make up.
 Age
Sex
Immunity level
Diet

19. Disease determinants
• Environmental and societal
determinants:
Poor housing conditions .
Presence of infectious agents.
Reservoirs in which organisms
multiply.

20. Disease control
• Keeping in mind all the above mentioned
things
steps or programs
can be implemented
to
control disease .

21. Historical background
Adam and eve - trying to
investigate qualities of forbidden
fruit .
Disease was a result of demons or
divine judgment by wrathful God or
Gods .
 It was refined that to an acceptance
that illness was a part of God’s plan .

22. Historical background
• The development of ancient Greece –
infections were caused by miasma or
effuvium , a putrid matter in the
atmosphere associated with dead bodies
or filthy living conditions .
With the work of Louis Pasteur &
Robert Koch – above philosophy was
refused .
 Germ theory of disease was accepted .

23. Historical background
• First known epidemiologist – Hippocrates
of Cos ( 460-375 B.C.).
• After his death – Greeks returned to their
priest healers .
• In mid 13th century – first medical
schools in Europe - dissections were
carried on executed criminals .

24. Historical background
• 17th century – Thomas Sydenham
,(1624-89) a London physician –
importance of careful clinical observations
• He wrote about histories of sick persons
– Founder of epidemiology .
• John snow(1813 – 58) – carried out the
classical study of cholera .

25. Historical background
• He pointed out that sailors were
attacked by cholera only when visiting
ports were the disease already existed.
• Central part of John Snow’s work –
description of cholera epidemic in Soho
, London in (1854) - 500 deaths
occurred over a period of 10 days.

26. Historical background
• Marking the location on a map he found
that a central point in Broad Street ,
was a pump from which local
inhabitants obtained their water.

27. Historical background
• William Bugg ( 1811 – 80) – typhoid .
• Mc Alistair (1941) – rubella and
pregnancy.
• R. Doll & Bradford – smoking &
carcinoma of lung .

28. Definitions..
• Epidemic : around people
• Pandemic : all people
• Endemic : within people

29. The occurrenceof cases of
illness or health
related events in a community or region,
clearly in excess of normalexpectancy.
Sudden outbreak of disease, rapidly,
spreading in a
small geographical region.
eg– Measles .
Definition

30. The constant presence of a disease
within
given
geographic area or population grou
EG. Malaria .
Definition

31. The cases occurring irregularly, haphazardly
from time to time.
eg :- Tetanus,Herpes zoster
Definition

32. An epidemic usually affecting
a large proportion
of the population and occurring
overa wide
geographic area.
eg :- Influenza
Definition

33. Aim of
epidemiology
“To eliminate or reduce
health problem or its
consequences and to
promote health and well
being of society as a
whole”.

34. Objectives of epidemiology
• To describe the distribution and
magnitude of health and disease
problems in the population .
• To identify etiological factors of the
disease .
• To provide data essential for planning ,
implementation and evaluation of
services for prevention , control and
treatment of disease and to setting up
of priorities for the same.

35. Epidemiology
Defined population
Disease pattern in
a community
Both sick & healthy
Clinical
medicine
a case
Disease in a single
patient
Only in the sick

36. Epidemiologist
goes to community
Makes a community
diagnosis
Use clinical
information
to complete their study.
Clinical medicine
Patient goes to
clinician
Makes a diagnosis
in individual
patient
Epidemiologist
conclusion to
make right
Epidemiology

37. Epidemiology
 Epidemiologist must
also have good
clinical knowledge.
 Concept is more of
holistic nature
Clinical medicine
Clinicians also require
sound knowledge
about epidemiology.
Biomedical nature .

38. Thank You