The document outlines the epidemiological triad, detailing agent, host, and environmental factors that contribute to infectious diseases. It categorizes agents into physical, chemical, biological, mechanical, socio-economic, and nutrient classes, while host factors include demographic and lifestyle characteristics. Environmental factors encompass physical, biological, and psychosocial elements influencing disease transmission.

1. Epidemiological
triad
Dr. Sunayana Kumthekar
Assistant Professor
GMC Jalgaon

2. Content
1. Agent factors
2. Host factors
3. Environmental factors
4. Question answer

3. Use
 Explains how infectious
diseases are caused and
transmitted.

6. AGENT
 A substance living or non-living, the
excessive presence or relative lack of
which produce a disease.
 Disease agent is considered as
“seed”

7. PHYSICAL AGENTS
EXCESSIVE HEAT , COLD , HUMIDITY ,
PRESSURE , RADIATION , ELECTRICITY ,
SOUND Etc.
SUN STROKE
FROST BITE
ELECTRIC SHOCK

8. CHEMICAL AGENTS
ENDOGENOUS EXOGENOUS
PRODUCED IN THE BODY ARISE OUTSIDE HUMAN HOST
PRODUCED DUE TO
DERANGEMENT OF FUNCTION
CAUSE DERANGEMENT OF
FUNCTION
e.g.. Serum bilirubin,urea,
ketones, uric acid
e.g. allergens, metals, fumes,
dust , gases , insecticides
NO BIOMAGNIFICATION BOIMAGNIFICATION A SERIOUS
PROBLEM

9. BIOLOGICAL AGENTS
-RTA, Domestic accident,
mechanical AGENTS
Socio-economic AGENTS
-RTA, Domestic accident,
mechanical AGENTS

10. NUTRIENT
AGENTS
Excess Or Deficient Intake Of Nutrients Results In
Nutritional Disorders
PEM : MARASMUS , KWASHIORKOR
ANAEMIA , VITAMIN DEFFICIENCIES
GOITRE

11. HOSt factors

12. Age
Sex
Ethnicity
 Genetic factors
 Biochemical levels of blood
 Blood groups and enzymes
 Immunological factors
 Physiological functions of
different systems of body
BIOLOGICAL
CHARACTERISTIC
S
DEMOGRAPHIC
CHARACTERISTIC
S

13.  Socio-economic
status
 Education
 Occupation
 Stress
 Marital status
 Housing etc.,
 Personality traits
 Living styles
 Nutrition
 Physical exercise
 Use of alcohol
,drugs and
smoking
 Behavioral patterns
etc.,
SOCIAL AND
ECONOMIC FACTORS
LIFE STYLE
FACTORS

14. AGE

15. sex

16. ETHNICITY
Negroes Sickle cell Anaemia
Mediterranean Thallasemia
Jews of Eastern Tay sachs
Europe

17. OCCUPATION
Alter the habit
pattern of
employees
Sleep, alcohol,
Drug addiction,
night shifts etc.,

18. Physical activity

19. SOCIAL CLASS
 Coronary heart disease
Hypertension
Diabetes mellitus

20. SOCIAL CLASS
 Lower class
LEPROSY
TUBERCULOSIS
CERVICAL CANCER
 Body weight, nutritional
status and behavior
leprosy

21. ENVIRONMENTAL
FACTORS

22. PHYSICAL ENVIRONMENT
All non-living things and physical
factors
Air, water, soil, housing climate,
geography, light Etc.,

23.  Developing countries
defective environment
Lack of sanitation

24.  Developed countries
Air pollution
radiation
Noise pollution

25. BIOLOGICAL
ENVIRONMENT
 Universe of living things
 Bacteria, viruses, insects, animals and
plants
 Disease producing agents,
 vectors of disease.

26. PSYCHOSOCIAL
ENVIRONMENT
Cultural values, customs, beliefs,
attitude, morals, religions, life styles
etc.,
both positive and negative aspects

27.  Positive side
Favorable social
environment
Sense of fulfillment
Quality of life

28.  Negative side
poverty, migration
Loss of employment
Anxiety, depression
frustration

31. 1. Enumerate Agent factors
i. Physical
ii. Chemical
iii. Biological
iv. Mechanical
v. Socio-economic
vi. Nutrient

32. 2. Enumerate Host factors
i. Age, Sex
ii. Ethnicity
iii. Education, Occupation
iv. Social group
v. Genetic
vi. Physical activity

33. 3. Environmental factors
i. Physical
ii. Biological
iii. Psychosocial

34. 4. Epidemiological triad consist of
what ??