Department of Community Medicine, BMC, SAGAR

1. SPECTRUM OF HEALTH AND
TYPES OF EPIDEMIC

3. What is health?
According to WHO-
“health is a state of complete physical,
mental and social well-being and not merely an absence of
disease and infirmity.”
In recent years it also include ability to lead a “socially and
economically productive life”

5. Positive health
 The state of positive health - "perfect functioning" of the body and mind.
 It conceptualizes health
-biologically, as a state in which every cell and every organ is
functioning at optimum capacity and in perfect harmony with the rest of
the body;
-psychologically, as a state in which the individual feels a sense of
perfect well-being and of mastery over this environment, and
-socially, as a state in which the individual's capacities for
participation in the social system are optimal.

6.  The lowest point on health disease spectrum
is death and the highest point corresponding
to the WHO of positive health.
 The spectrum concept of heath emphasizes
that the health of an individuals is not static:
is a dynamic phenomenon and a process of
continuous change, subjects to frequent
subtle variations.

7.  Health fluctuates within a range of optimal
well being to various levels of dysfunction,
including the state of total dysfunction,
namely death.
 The transition from optimum health to ill
health of often gradual and where one state
ends other state begins.

8.  It implies that health is a state not to be
attained once and for all, but ever to be
renewed. There are degrees or “levels of
health” as there are severity of illness.

10. Determinants of health

11. Determinants
1. Biological
2. Behavioural
3. Environmental
4. Socio-economic
5. Health system
6. Sociocultural
7. Ageing of the population
8. Science and technology
9. Information and Communication
10. Gender
11. Equality and social justice
12. Human rights

12. Social factors influencing the health of people

14. What is Epidemic?
An epidemic is defined
“as unusual increase in number of
cases of illness or other health related events in a
defined geographical areas and defined time periods.”

15.  Common source epidemic
• Single exposure or “point source” epidemics.
• Continuous or multiple exposure epidemics.

16. • Propagated Epidemics
• Person to person
• Arthropod vector
• Animal reservoir
• Slow ‘modern’ Epidemic: NC “non-
communicable diseases”
 Mixed Epidemics

17. I-Common Source Epidemic
(A)Single-exposure “point’ epidemics
 Exposure is brief and simultaneous (immediate or
concurrent) exposure.
 All cases develop within one incubation period (food
poisoning epidemics).

18. Features of epidemic curve:
 1.Rises and falls rapidly, no secondary waves.
 2. Tends to be explosives, with clustering of cases
within narrow interval of time.
 3. All cases develop within one incubation period.

19. Epidemic curve showing median incubation period
during common source, single exposure epidemics

20. (B) Common source, continuous exposure
 The exposure from the same source may be
prolonged- continuous, repeated or intermittent
 No explosive rise in number of cases
 Cases occur over more than one incubation period

21. (B) Continuous or repeated exposure
 Frequently not always due to exposure to an
infectious agent
 They can result from contamination of the
environment (air, water, food, soil) by industrial
pollutants
 Minamata disease in Japan from consumption of fish
containing concentration of methyl mercury

22. Epidemic curve showing single incubation period
during common source,continous exposure

23. Outbreak of respiratory illness, the legionnaire
disease in 1976 in USA was a common source,
continuous or repeated exposure, no evidence of
secondary cases.

24. Epidemic curve showing irregular peaks of single incubation
period during common source,interrupted exposure

26. Propagated Epidemics
 Epidemics may start from a common source and then
continue as a propagated epidemics
Water borne epidemic as example the epidemic reaches a
sharp peak, tails (end) off gradually over longer time of
period.

27.  Of infectious origin, with person to person transmission
(hepatitis A,E and polio epidemics).
 Gradual rise and tails off over longer period of time.
 Transmission continues till depletion of susceptible or
susceptible individuals are no longer exposed to source of
infection.
 Communicability (speed of spread) depends on herd
immunity among exposed and opportunities for contact
with infective dose and secondary attack rate

28. Epidemic curve showing propogated epidemics

29. Mixed epidemic
 The curves shows feature of both common source and
propagated epidemics.
 For instance, a common source outbreak followed by
secondary person-to-person spread.
 Example-Epidemic caused by enteropathogens.

30. References
 K. Park , Park’s Textbook Of Preventive And Social
Medicine, M/S Banarsidas Bhanot Publishers, 25th
Edition,2019
 AM Kadri, IAPSM’s Textbook Of Community
Medicine, Jaypee Brothers Medical Publishers, 1st
Edition. 2019
 Roger Detels Et Al, Oxford Textbook Of Global Public
Health, Oxford, 6th Edition