The document outlines key concepts in health, including the WHO definition of health, determinants and dimensions of health, epidemiology, modes of disease transmission, levels of prevention, and health indicators. It also details various epidemiological tools, rates, and measures such as prevalence, incidence, attack rate, and indicators for mortality and morbidity. Additionally, it discusses the Sustainable Development Goals related to health, disease control concepts, and the processes of monitoring and surveillance in public health.

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Tutorial Day 4

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What is health ?
WHO definition:- Health is a complete physical, mental & social well-
being and not merely an absence of disease or infirmity.
In recent years, this statement has been amplified to include the ability
to lead a “socially and economically productive life”.

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Determinants of health
• Biological
• Behavioral & Socio-cultural coditions
• Environmental
• Socio-Economic Conditions
• Health Services
• Ageing of the population
• Gender
• Human Rights
• Equity & social justice
• Science & Technology
• Information & Communication

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Dimensions of health
• Physical
• Mental
• Social
• Spiritual
• Emotional
• Vocational
• Others

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ICEBERG Phenomenon

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Not shown by
• Measles
• Tetanus
• Rubella
• Pertusis
• Rabies

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EPIDEMIOLOGY
• The study of the occurrence and distribution of health-related events,
states, and processes in specified populations, including the study of
the determinants influencing such processes, and the application of
this knowledge to control relevant health problems

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Epidemiological Triad:
Agent
Host Env Factors

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Chain of infection

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Components of epidemiology:
• Disease frequency
• Distribution-Time, Place, Person
• Determinants-Eg.-Lung cancer, CVD

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Tools of Measurement in epidemiology:
• Rate-Numerator, Denominator, Time specification & Multiplier
• Ratio-Numerator is not a component of the denominator
• Proportion- is a ratio that indicates the relation in the magnitude of a
part of the whole. The numerator is always included in the
denominator

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Incidence
• The Number of new cases
occurring in a defined
population during a specified
period of time
• I=No. of new cases of specified
ds. during a given time
period/Population during that
period×1000
Prevalence
• A Total number of individuals
who have an attribute or disease
at a particular time(or during a
particular period) divided by the
population at risk of having the
attribute or disease at this point
of time or midway through the
period

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Endemic, Epidemic,Pandemic
• Endemic: constant presence of disease or infectious agent within a
given geographic area or population group without importation from
outside
• Epidemic: The occurrence in a community or region of cases of an
illness, specific health-related behaviour, or other health –related
events clearly in excess of normal expectancy
• Pandemic: An epidemic occurring over a very wide area, crossing
international boundaries, and usually affecting a large number of
people

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Modes of transmission:
Direct
• Direct contact
• Droplet infection
• Contact with soil
• Inoculation into skin or mucosa
• Transplacental
Indirect
• Vehicle borne
• Vector borne-Mechanical,
Biological
• Air borne-Droplet nuclei, Dust
• Fomite Borne
• Unclean hands and fingers

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Carrier & Types of carrier:
• An infected person or animal that harbors a specific infectious agent
without discernible clinical disease and serves as a potential source of
infection for others.
• By Type: Incubatory Carriers, Convalescent Carriers, Healthy Carrier
• By Duration: Temporary,Chronic

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Incubation Period:
• The time interval between invasion by an infectious agent and the
appearance of the 1st
sign or symptom of the disease in question

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Levels of prevention
Natural history of disease

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• Primordial- before the emergence of risk factors
Health education
• Primary- risk factor present but no disease
prevention in pre pathogenesis stage
Health promotion & Specific protection
• Secondary- disease started
pathogenesis phase
Early Dx and T/t
• Tertiary- Diseases in progress/over
Disability limitation, Rehab

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Attack rate & Secondary attack Rate & Case
fatality rate :
• Attack Rate: No. of new cases of a specified ds. during a specified time
interval/Total population at risk during the same interval×100
• SAR: No. of exposed persons developing the disease within the range
of incubation period following exposure to a primary case
• Case fatality rate: No.of deaths from a specified disease during a
specified time period /no, of cases of the disease during the same
time period×100

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PQLI & HDI

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• PQLI :- Physical quality of life index (1-100)= India 77.67(rank 117/193)
1. Literacy rate
2. Infant mortality rate
3. Life expectancy @1 yr of age
• HDI:- Human development Index (0-1)= India 0.644 (rank 134/ 193)
1. Mean years of schooling/Education index/ Enrollment ratio
2. Purchasing power parity/ income per capita
3. Life expectancy @birth
Highest PQLI state
Lowest PQLI state
Odisha?
Highest HDI state
Lowest HDI state
Odisha?

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Mortality Indicators
Crude death rate
Life expectancy
MMR (rate/ratio)
IMR
Under 5 Mortality rate
Age-specific death rate
Case fatality rate

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Morbidity Indicators
Incidence
Prevalence
Notification rate
Admission rate
Discharge rate

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Disability Rates
Event type ( No of days restricted/ Bed disability days/ work loss days)
Person type ( Limitation of mobility/ Limitation of activity)
DALE
QALY
DALY=(YLL+YLD)

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SDG

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Health specific goal
• SDG3 – Good Health & well being ; Ensure healthy lives & promote
well being for all at all ages

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Disease Control:
• Reduction In transmission to such a low level that it stops to be public
health concern
• Reduction in INCIDENCE
DURATION
FINANCIAL BURDEN
COMPLICATIONS

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ELIMINATION
• Complete interruption of transmission but organism still present
• Regional/ country term
• Guinea worm 2000
• Leprosy 2005
• MT, NT 2016
• Yaws 2016

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ERADICATION
• Complete extermination of organism
• Global term
• All or none phenomenon
• Small pox 8th
may 1980
• Polio virus Type2 20th
sept 2015
• Rinderpest (cattle disease)

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Monitoring vs Surveilance
• Monitoring- analysis of performance of routine measurement
• Surveillance – ongoing systematic process of all factors affecting a
disease ( data collection, compilation, compilation, analysis and
interpretation and its application)

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• Monitoring
• Continuous overlooking
progress of health activity
• No inbuilt action
component
• No feedback
• One time linear process
• Smaller concept
• Surveillance
• Continuous scrutiny of all factors affecting a
disease with attention, authority & suspicion
• Inbuilt action component is present
•
• Feedback is inbuilt
• Cyclical continuous process
• Broader concept

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Sentinel Surveillance
• Used to identify missed or hidden cases
• HIV- in blood bank, anti natal clinic, STD clinic
• Identify both old and new cases

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Types of study design in epidemiology:
Observational:
• Descriptive: Case Report, Case
Series,
• Analytical: Cross-sectional,
Cohort, Case-control, Ecological,
Nested case-control
Experimental/interventional
• Randomized Control trials
• Field trial
• Community trial

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Blinding
• A process where study participants are prevented from knowing
certain information that may somehow influence them.
• Single blind: participants
• Double blind: Doctor & Study participants
• Tripple blind: Investigator, participant, person analyzing data

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Randomization
• Randomization is a statistical procedure by which the participants are
allocated into groups usually called study and control groups, to
receive or not to receive an experimental preventive or therapeutic
procedure, manoeuvre, or intervention