1. Presentation By: Urooj Ilyas
Iqra Zulfiqar, Samia Yaqoob
& S.M. Hasnain Ali Naqvi

2. • Introduction by Samia Yaqoob
• Broad types of Epidemiology by Urooj Ilyas &
Iqra Zulfiqar
• Role & Importance of Epidemiology by S.M.
Hasnain Ali Naqvi
• Question Session

3. Epidemic, Epidemiology & Basic terminologies

4. • (epi), meaning "upon or above" and
• (demos), meaning "people“
• Generally occurs when new cases of a certain disease, in
a given human population, and during a given period.
• Epidemiologists often consider the term outbreak to be
synonymous to epidemic.
Types:
• Common source outbreak
• Propagated outbreak

5. Spread of disease
and increase no. of
infected people by
increase of days

6. • CLASSICALLY SPEAKING: Combination of three Greek
words
• Epi = upon
• Demos = people
• Ology = science
• Epidemiology = the science which deals with what falls upon
people…..
• Bridge between biomedical, social and behavioral sciences
• SIMPLE OLD DEFINITIONS:
• Oxford English Dictionary
THE BRANCH OF MEDICAL SCIENCE WHICH TREATS EPIDEMICS
• Kuller LH: American J of Epidemiology 1991;134:1051
EPIDEMIOLOGY IS THE STUDY OF "EPIDEMICS" AND THEIR
PREVENTION
• Anderson G. In: Rothman KJ: Modern Epidemiology
THE STUDY OF THE OCCURRENCE OF ILLNESS

7. • Now a days it is defined as:
Science concerned with the study of the factors,
determining and influencing the frequency of
distribution of disease, injury or other health related
events and their causes in a defined human population
for the purpose of establishing programs to prevent
and control their development and spread.
Types of
Epidemiolo
gy
according
to their
study zone
 Veterinary Epidemiology/Epizoology
 Botanical Epidemiology
 Microbial Epidemiology

9. Source of epidemics

10. • Close association between the triangle of epidemiology
and the chain of transmission
• Disease transmission occurs when the pathogen or
agent leaves the reservoir through a portal or exit and
is spread by one of several modes of transmission.
• Breaks in the chain of transmission will stop the spread of
disease
Etiological
agent/pathway Source /
Reservoir
Mode of
transmission
Host

11. Types & their triads

12. DESCRIPTIVE
EPIDEMIOLOGY
• Examining the distribution of
a disease in a population,
and observing the basic
features of its distribution in
terms of time, place, and
person. We try to formulate
hypothesis, look into
associations
• Typical study design:
community health survey
(synonyms: cross-sectional
study, descriptive study)
ANALYTICAL
EPIDEMIOLOGY
• Testing a specific hypothesis
about the relationship of a
disease to a specific cause,
by conducting an
epidemiologic study that
relates the exposure of
interest to the outcome of
interest (Cause-effect
relationship)
• Typical study designs:
cohort, case-control,
experimental design

13. To undertake an analytic epidemiologic study we must first:
• Know where to look
• Know what to control for
• Be able to formulate / test hypotheses compatible with a
field evidence
• Outbreaks in a population often involves several factor
and entities
• Many people, objects, avenues of transmission, and
organisms can be involved in the spread of disease
• Epidemiologist have created a model to help explain the
multifaceted phenomena of disease transmission: the
epidemiology triangle

14. • The three essential characteristics of disease we
look for in descriptive epidemiology are:

15.  Age
 Gender
 Socio-economic status
(education, occupation,
income)
 Marital status
 Ethnicity/race/genetic
profile
 Behavior / habits
1. PERSON
(WHOM)

16.  Geographically restricted or
widespread (outbreak,
epidemic, pandemic) Off-
shore (tsunami…)
 Climate effects
(temperature, humidity,
combined effects..)
 Urban / sub-urban-squatter /
rural
 Relation to environmental
exposure
(water, food supply, etc)
 Multiple clusters or one
2. PLACE
(WHERE)

17. Year
Season
Month
Week
Hour of onset
Duration
3. TIME
(WHEN)

18. • The three essential phenomena of disease we
look for in analytical epidemiology are:

19.  Biological agents
 Nutritive agents
 Physical agents
 Chemical agents
 Mechanical agents
&
 Social agents
1. AGENT

20.  Demographic factors
 Biological factors
 Socio-economic factors
 Life style
2. HOST

21.  Physical environment
 Biological environment
 Psychological environment
3.
ENVIRON-
MENT

22. • host, agent and environmental factors are not in
balance
• due to new agent
• due to change in existing agent (infectivity,
pathogenicity, virulence)
• due to change in number of susceptibles in the
population
• due to environmental changes that affect
transmission of the agent of growth of the agent

23. • The mission of the epidemiologist is to break one
of the legs of the triangle, which disrupts the
connection between environment, host, and
agent, and interfered with, altered, changed or
removed from existence stopping the
continuation of an outbreak.
• The goals of public health are the control and
prevention of disease.
• By breaking one of the legs of the triangle, public
health intervention can partially realize these
goals and stop epidemics.

24. Pharmaco-epidemiology

25. Community diagnosis
Determination of health status
of population
Identifying risk factors for
disease prevention
Identification of syndromes
Evaluation of a community
program
Completing the clinical picture

26. COMMUNITY
PHARMACIST
 Interact with patients on daily basis
 Collaborate with health department or Health
planning agencies in order to give updated
knowledge to patients and society about
epidemics.
 Study about the pharmacoepidemiology i.e.,
gathering information about the new drugs their
effects and risks and assessments with its early
uses regarding epidemic diseases.
Outcom
e
Through the active part of pharmacist a
checking system is designed, researches and
new studies regarding treatments ease the
patient and helpful in healthcare system.