The document discusses epidemiology and its applications. It defines epidemiology and describes its purposes such as preventing and controlling health problems. It outlines epidemiological methods like observational and experimental studies. Descriptive epidemiology aims to study disease frequency and distribution while analytical epidemiology tests hypotheses. The roles of nurses in applying epidemiological concepts to assess community health needs and evaluate prevention programs are also highlighted.

1. SEMINAR
ON
EPIDEMIOLOGY
PRESENTED BY
MR. CHETAN AMBUPE
FINAL YEAR M.SC (N)

2. DEFINITIONS
• The epidemiology is that branch of medical
science which deals with epidemics
(Parkin, 1873).
• Epidemiology is the science of mass
phenomena of infectious diseases
(Frost, 1927).
• Epidemiology is the study of disease, any
disease, as a mass phenomenon
(Greenwood, 1934).

3. • Epidemiology is the study of the frequency,
distributions and determinants of health
related states or events in specified
population and the application of this study
to control health problems (Last, 1988).

4. PURPOSES
• To prevent, control and eradicate health and
health related problems.
• To reduce/minimize the impact of these
problems.
• To promote health and quality of life of people
at large.

5. OBJECTIVES OF EPIDEMIOLOGY
• Study of frequency and distribution of
health and health related problems in
community at large.
• Identification of determinants i.e. etiological
factors causing health and health related
problems.

6. • Need based planning and administration of
comprehensive health care programmes
with the available resources to deal with
health and health related problems.
• Evaluating the effectiveness of the
programmes to provide feedback.

7. USES OF EPIDEMIOLOGY
 Study the occurrence and distribution of
diseases in a community.
 Identify the determinants of diseases.
 Diagnose the health status of the community
 Estimate the risk
 Plan effective need based health care
services

8.  Determine the effectiveness of health care
services planned.
 Determine the usefulness and
effectiveness of new/innovative
techniques, measures and programmes
 Complete the clinical picture of chronic
diseases arid slow growing diseases

9.  Identify syndromes by describing the
distribution and association of clinical
phenomena in the population.
 Forecast the likely occurrence of diseases
on the basis of epidemiological principles

10. THEORIES AND MODELS OF DISEASE
CAUSATION
Supernatural theory

11. The Germ Theory

12. Theory of Epidemiological Triad

13. Multifactorial Causation Theory

14. Web of Causation

15. Dever’s Epidemiologic Model

16. EPIDEMIOLOGICAL METHODS
 OBSERVATIONAL STUDIES
 Descriptive studies
 Analytical studies
 EXPERIMENTAL STUDIES
 Randomized control trials
 Field trials
 Community trials

17. Descriptive Method

18.  Descriptive method of epidemiological study
is concerned with the study of frequency and
distribution of disease and health related
events in population in terms of person,
place and time.

19. Personal characteristics such as
age, sex, race, marital
status, occupation, education, income, social
class, jury pattern, habits.

20. Place distribution of cases i.e. areas of high
concentration, low concentration and spotting
of cases

21. Time distribution/trends such as year,
season, month, week, day and hour of onset of
the disease

22. There are two different designs to
conduct descriptive studies in
epidemiology:
1) Cross-sectional studies:
2) Longitudinal Studies:

23. USES OF DESCRIPTIVE EPIDEMIOLOGY
 Provide data regarding the magnitude of the
disease load & types of disease problems in the
community in terms of morbidity & mortality rates
& ratios.
 Provide clues to disease etiology & help in the
formulation of an etiological hypothesis.
 Provide back ground data for planning,
organizing , & evaluating preventive & curative
services.
 Contribute to research by describing variation in
disease occurrence.

24. Procedures in descriptive studies
 Define the population to be studied
 Defines the disease
 Describe the disease
 Time, place and person
 Measurement of disease
 Comparing with known indices
 Formulation of hypothesis.

25. ANALYTICAL EPIDEMIOLOGY
 The object is not to formulate hypothesis but
to test hypothesis.
 It contains two types:
 CASE CONTROL STUDY
 COHORT STUDY

26. CASE CONTROL STUDY {RETROSPECTIVE
STUDIES}
HAS 3 DISTINCT FEATURES:
• Both exposure & outcome has occurred before
the onset of study
• Study proceeds backwards from effect to cause
• It uses a control or comparison group to support
or repute an inference.

28. There are four basic steps in
conducting a case control study:
1. Selection of cases and controls
2. Matching
3. Measurement of exposure, and
4. Analysis and interpretation.

29. COHORT STUDY
FEATURES ARE:
• Cohorts are identified prior to the
appearance of disease under
investigation.
• Study groups are observed for a period of
time to determine the frequency of disease
among them.
• Study proceeds forward from cause to
effect.

31. ELEMENTS OF A COHORT STUDY
1. Selection of study subjects
2. Obtaining data on exposure
3. Selection of comparison groups
4. Follow – up, and
5. Analysis.

32. Experimental Method

33. Experimental studies are similar in
approach to cohort studies except that
conditions are under the careful control
of investigator

34. Experimental studies are of two types:
a. Randomized controlled trials; and
b. Non-randomized or “non-experimental”
trials

35. EPIDEMIOLOGICAL MEASUREMENTS
1.Mortality Rate (Death Rate)
2. Morbidity Rates -

36. EPIDEMIOLOGICAL APPROACHES
1. Asking questions and making observations.
2. Making comparisons.

37. PREVENTIVE EPIDEMIOLOGY

38. Health surveys
Health surveys are investigations to identify the
frequency, distribution and the determinants of
health related events or states in the community.
Health surveys help in knowing the community
and making community diagnosis.

39. i) Questioning
ii) Health examination and lab. Investigations
iii) Record review
iv) Observation

40. SCREENING
Screening form health point of view is defined as
the method of search for unrecognized diseases
by means of rapidly applied tests, examinations or
procedures in apparently healthy population.

41. Mass Screening:
Multiphase Screening:
Selective or High Risk Screening :

42. SURVEILLANCE
Epidemiologically surveillance means close
vigilance on occurrence and distribution of
diseases and health related
problems, population dynamics, community
behavior and environmental processes resulting
in increased risk of ill health in the community.

43. Individual/Family Surveillance:
Community/Local Population Surveillance
National surveillance:
International surveillance:

44. MONITORING
Monitoring is day to day measuring and analysis i.e
making assessment of: health status of people and
their environment to determine any changes;
„performance of health services and health professional
to determine effectiveness and efficiency; health
behavior of client to determine compliance of behavior.

45. DYNAMICS OF DISEASE TRANSMISSION:

46. 1. The Reservoir.
2. Mode of Transmission.
3. Susceptible Host.

47. Reservoir of infectious agent:
In simple terms, reservoir means the natural
habitat. The reservoir of infectious agent is
any person, animal, arthropod, Plant, soil
and any substance.

48. Types of Reservoir
1. Homologous Reservoir
2. Heterogonous Reservoir

49. HUMAN RESERVOIR
The human is the source of infection and
act as a host for infectious agent. Human
itself is responsible for spreading many
diseases in humans either by suffering
and carrying the infectious agent

50. HUMAN RESERVOIR IS OF TWO TYPES
1. Cases
The cases are of following types:
 Clinical cases
 Sub clinical cases
 Latent cases

51. 2. CARRIERS:

52. MODES OF TRANSMISSION
DIRECT TRANSMISSION
• Direct contact
• Droplet infection
• Contact with soil
• Inoculation into skin or mucosa
• Trans placental or vertical transmission

58. INDIRECT TRANSMISSION
• Vehicle borne
• Vector borne
• Air borne
• Fomite borne
• Unclean hands & fingers

64. SUSCEPTIBLE ‘HOST
 The infectious agent enters the
susceptible host after finding a portal of
entry such as respiratory tract, alimentary
tract, skin etc. Inside the human host, on
getting appropriate environment, it
multiplies and sufficient density of the
disease agent is built up to disturb the
health equilibrium and the disease
become overt.

65. LEVELS OF PREVENTION
 PRIMARY PREVENTION
 SECONDARY PREVENTION
 TERTIARY PREVENTION

69. IMPLICATIONS OF EPIDEMIOLOGY IN C.H.N
PRACTICE
 An understanding of epidemiological
concepts & principles are vital for nurses in
the community as well as hospital setting.
 Knowledge of methods of epidemiology is
useful to the C.H. nurse, both as tool in
conducting the investigation to evaluate &
explain phenomena observed in the course
of work & as a basis for interpreting &
evaluating the epidemiological literature.

70.  Epidemiological methods such as measures
of health , serve as tools for assessing
community needs & evaluating the impact
of C.H. programmes of disease prevention
& health promotion.
 The body of knowledge derived from
epidemiological studies , including the
natural history & patterns of disease
occurrence & factors associated with high
risk for developing disease, serves as an
information base for C.H. practice .
 It provides a frame work for planning,&
evaluating community intervention
programmes.

71.  Serves as a basis for assessing
individual & family health needs & for
planning nursing interventions.
 Provides tools for evaluating success of
interventions.
 Nurses may be the one who initiate a
study & more frequently assist in data
collection.
 In actual practice, C.H. nurse is
considered as the foot soldier in the
army of epidemiology.
 Epidemiologist depend on C.H. nurse
for follow- up on various conditions.

72. ROLE OF NURSE IN EPIDEMIOLOGY:-

73.  She makes use of nursing process which is
comparable to epidemiological process in
solving the problem.
 She identifies & investigating the
problem, formulates interventions & implements
to prevent & control the problem & evaluate the
effectiveness of intervention.
 She deals with the problem independently
especially when these are nursing
problem, minor ailments.
 She may participate as one of the team
members.

74.  She participates in data collection, data
analysis, planning, implementation & evaluation.
 She play active role in prevention & control of
communicable diseases.
 Community health nurse can also teach &
supervise other workers in surveillance
activities.
 She also participates in National programs.

75. Conclusion:-
 Epidemiology is one of the basic sciences
applicable to nursing. Nurses working in
the community deal with the people in
various settings and help them to solve
their health problems. Nurses in the
community have an active role in
prevention and control of communicable
diseases