EPIDEMIOLOGY OF ACUTE DIARRHEA
Occurrence:
Diarrhea is a major health problem in developing countries including Bangladesh. An estimated 73.5 million episodes and 0.26 million episodes and 0.26 million deaths occur each year in those under 5 years of age in Bangladesh. About 80% of deaths due to diarrhea occur in the first 2 years of life.
Epidemiological Triad:
1. Agent: There are many causative agents for acute diarrhea.
The most common ones are-
1. Bacterial: Enterotoxigenic E.coil
shigella
Enteropathogenic E.coil
V. cholera
Campylobacter jejune
Salmonella
2. Viral: Rotavirus
3. Protozoa =>E.histolytica,G. lamblia.
Host:
*Age most diarrheal episodes occur during the first 2 years of life. Incidence is highest in the age group 6-11 months, when weaning often occurs.
It is also common for babies less than 6 months of age fed on cow's milk or infant feeding formulas.
*Factors increasing susceptibility to diarrhea
1. Failing to breastfeed until at least 2 years of age.
2. Malnutrition.
3. Measles, it may cause immunological impairment.
4. Immunodeficiency or immunosuppression. This may be temporary, e.g. after certain viral infections or it may be prolonged, as in people with Acquired immunodeficiency Syndrome (AIDS). When immunosuppression is severe, diarrhea can be caused by unusual pathogens and may also be prolonged.
5. Unhygienic personal and food habits.
ENVIRONMENT:
*Season-Distinct seasonal patterns of diarrhea occur in many geographical areas. In Bangladesh usually, two peak seasons are seen, premonsoon and postmonsoon. Here diarrhea due to V. Cholera usually occurs after the monsoon; due to enter toxigenic E coil in the hot dry summer; due to shigella in the winter
* Environmental factors facilitating transmission of diarrhea-
1. Moist and warm climate;
2. Overcrowded living condition;
3. Lack of safe drinking water;
4. Improper excreta disposal
5. Unhygienic home surroundings
6. Natural or man-made disasters.
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