Epidemiology Introduction

1. Epidemiology its
principle prevention
and control

2. Basic terminologies!
▸ Sporadic - Occurring at irregular intervals or only in a few places;
scattered or isolated.
▸ Endemic – A disease that is constant present at steady
frequency within a particular area.
▸ Epidemic – A widespread occurrence of an infectious disease in
a community at a particular time.
▸ Pandemic - (of a disease) prevalent over a whole country or the
world.

3. What is epidemiology?
 EPI – Upon / On / Befall
 DEMOS – Population / People
 LOGOS – The study of
Epidemiology is 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.

4. The Origin of Epidemiology
Dr. John Snow
• Father of epidemiology.
• Careful mapping of Cholera cases in East
London during cholera epidemic of 1854.
• Traced sources to a single well on broad
street that had been contaminated by sewage.

5. Principles
Distribution - Epidemiology is concerned with the frequency and pattern of health
events in a population.
Determinants - Epidemiology is also used to search for causes and other factors that
influence the occurrence of health-related events.
Specified populations - Epidemiologists are concerned with the collective health of
people in a community or other area and the impact of health events on that
population.
Application - Epidemiology provides data for directing public health action.

6. Epidemiology and Public
Health
• Epidemiology is the basic science of Public Health.
• Epidemiology is a quantitative discipline (probability, statistics, and
sound research methods).
• A method of casual reasoning based on developing and testing
hypotheses to explain health- related behaviors, states and events.
• This informs Public Health services, which play a key role in
assuring the health and well-being of communities. (CDC,2012)

9. Purposes and Aims of
Epidemiology
To estimate the etiology
of a disease.
To estimate the
spectrum of a disease.
Evaluate the
effectiveness of
interventions and public
health programs.
To predict disease
trends.
Identification of the
natural history of a
disease.
To identify risk factors
and protective factors.

10. The chain of
Infection
How an infection spreads?

11. 1 X 1031
An estimated 10 nonillion individual viruses
exist on our planet.

12. How viruses mutate?

13. How viruses mutate?

14. Major Pandemics & Epidemics.
(1347-1353)
75-200 million people
lost their lives.
(1918–1920)
17-100 million people
lost their lives.
(1855-1960)
12-15 million people
lost their lives.
Europe, Asia, and
North Africa
Worldwide
Spanish Flu
Third Plague Pandemic
Black Death
Worldwide

15. Major Pandemics & Epidemics.
(1968-1969)
1-4 million people lost
their lives.
(2019-Present)
6.3-25 million people lost
their lives as of May 2022.
(1981-Present)
36 million people lost
their lives as of 2020.
Worldwide Worldwide
Covid-19
pandemic
HIV/AIDS global epidemic
Hong Kong Flu
Worldwide

16. Vaccinated
Only 57 countries have vaccinated 70% of their population for
covid 19 – almost all of them high-income countries.
Success
We must vaccinate 70% of the global population specially
in the 3rd world countries.
Unvaccinated
Almost one billion people in lower-income countries remain
unvaccinated for covid 19.

17. Endemics and Epidemics in
Pakistan
Dengue
Naegleria fowleri
Hepatitis
Cholera
Malaria
Polio

18. Prevention and Control of
Epidemics
3. Vector Control
measures
Getting rid of the vector if
infection spreads thorugh it.
I.e. Aedes mosquito in
transmission of dengue.
1. Removal of source of
infection
Using drugs and vaccines to
prevent infection.
2. Prevent Transmission
By isolation, sanitation, hygiene, and education.

19. General Principles of Preventing
Transmission
1. Verify the Diagnosis: It is very important to promptly
establish or verify the etiologic agent responsible for the
disease.
2. Minimize the Duration of the Case's Infectivity: Drugs
(antimicrobials) are the most important means to shorten
the duration of infectivity for many diseases.

20. General Principles of Preventing
Transmission
3. Put into Effect Practices for Preventing Transmission: Disinfect and dispose
of contaminated material (e.g., blood, saliva, feces, urine, eating utensils,
bedding, clothes, toys, etc.)
• Encourage behavioral practices of the case (e.g., handwashing, covering the
nose and mouth when coughing/sneezing, protecting lesions from contact with
another person. Also, there may be a need for changes if individual is a food
handler.
• Isolate the case -- the duration and degree depends upon the illness.

21. Controlling epidemic
diseases
▸ Early detection
▸ Contact tracing
▸ Isolation
▸ Quarantine
▸ Good hygiene
practices
▸ Use of personal
protective
equipment (PPE),
which decreases
the disease spread
The movement include control measures,

22. Yes, we are constantly evolving and
so does bacteria and viruses.
Will there be
anymore
outbreaks in
the future?

23. Why Do We Investigate
Outbreaks?
▸ Outbreak investigations may be
considered as opportunities to study
disease events and are training
exercises for those conducting the
investigation. If cases are continuing to
occur, the goal may be to prevent
additional cases. If an outbreak appears
to be almost over, the goal may be to
prevent outbreaks in the future.

24. General Outbreak
Investigations
▸ Outbreaks may be detected when
routine, timely analysis of surveillance
data reveals an increase in reported
cases or an unusual clustering of cases.
The weekly tabulation of disease
reports by county is a useful way to
monitor trends, evaluate geographical
distribution throughout the state and
identify possible clusters.

25. Lessons learned from covid 19
outbreak
Immunization
Development of better and high
efficacy vaccines.
Sanitation
Supply of clean water and
proper disposal of waste is one
of the major preventive
measure.
Medical workforce
Encouraging more people to
become healthcare workers can
save us from next outbreak.
Hospital capacity
Increasing number of hospitals
is very important. There should
be atleast 1 large hospital in an
area.
Good hygiene
Good personal hygiene is one
of the best ways to protect
yourself from getting infectious
diseases.
Awareness
Awareness and education
about a certain infection helps
us bust the myths and stop
people from spreading
rumours.

26. Summary
Epidemiology study of :
Scientific, systematic,
data-driven of the
distribution
(frequency, pattern).
Determinants
(causes, risk
factors).
States and events in
specified
populations.
The application to
control of health
problems.

27. “
Conclusion!
The findings of the study support the effectiveness in
breaking the chain of Epidemics disease transmission
dynamics. This suggests that implementation of isolation,
quarantine, and good hygiene practices be carried out and
sustained until the outbreak stops, hence these practices
would effectively address the issues!

28. References
▸ ncbi.nlm.nih.gov/pmc/articles/PMC7178878/
▸ cdc.gov/csels/dsepd/ss1978/lesson1/section1.html
▸ https://www.dhss.delaware.gov/dph/epi/principles.html

29. Thank you!

30. Tatveel Tayyab
Microbiology Student
Rabia Furqan
Microbiology Student