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Diarrhoea is defined as the passage of loose, liquid or watery stools. These liquid stools are usually passed more than three times a day. However, the change in consistency and character of stools are more important than the number of stools.
The term "diarrhoeal diseases" should be considered only as a convenient expression-not as a nosological or epidemiological entity - for a group of diseases in which the predominant symptom is diarrhoea. The division between acute and chronic diarrhoea is arbitrary. Diarrhoeas lasting 3 weeks or more may be called chronic. The WHO/UNICEF define "acute diarrhoea" as an attack of sudden onset which usually lasts 3 to 7 days. but may last up to 10-14 days. It is caused by an infection of the bowel. The term gastroenteritis is most frequently used to describe acute diarrnoea. In many cases of diarrhoea stools are watery but if blood is visible in stools, the condition is called dysentery.
Epidemiological Determinants
Agent Factors
In developing countries, diarrhoea is almost universally infectious in origin. A wide assortment of organisms cause acute diarrhoea, and many of them have been discovered only in recent years such as rotaviruses and campylobacters (Table 2).
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TABLE 2 Infective agents causing diarrhoea
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Viruses
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Rotaviruses, Astrovi ruses Adenoviruses Calciviruses Coronaviruses Norwalk group viruses Enteroviruses
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Bacteria
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Campylobacter jejuni, Escherichia coli, Shigella, Salmonella, Vibrio cholera, Vibrio parahaemolyticus, Bacillus cereus
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Others
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E. histolytica, Giardia intestinalis, Trichuriasis, Cryptosporidium SPP, Intestinal worms
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Reservoir of Infection
Man is the principal reservoir and transmission originates from human factors for enterotoxigenic E. coli, Shigella spp., V cholerae,, Giardia lamblia and E. histolytica. Animals are important reservoirs and transmission originates from both human and animal faeces for Campylobacter jejuni, Salmonella spp and Y enterocolitica. For viral agents of diarrhoea, the role of animal reservoirs in human disease remains uncertain.
Host Factors
Diarrhoea is most common in children especially those between 6 months and 2 years. Incidence is highest in the age group of 6-11 months, when weaning occurs. It reflects the combined effects of declining levels of maternally acquired antibodies, the lack of active immunity in the infant, the introduction of contaminated food, and direct contact with human and animal faeces, when the infant starts to crawl. It is also common among babies of less than 6 months of age fed on cow's milk or infant feeding formulas. Diarrhoea is more common in persons with malnutrition. Malnutrition leads to infection and infection to diarrhoea which is a well known vicious circle. Poverty prematurity, reduced gastric acidity, immunodeficiency, lack of personal and domestic hygiene and incorrect feeding practices are all contributory factors.
Environmental Factors
Distinct seasonal patterns of diarrhoea occur in many geographical areas. In temperate climates, bacterial diarrhoea occur more frequently during the warm season, whereas viral diarrhoea, particularly that caused by rotavirus peak during the winter. In tropical areas, rotavirus diarrhoea occurs throughout the year, increasing in frequency during the drier, cool months, whereas bacterial diarrhoeas peak during the warmer; and rainy season. The incidence of persistent diarrhoea follows the same seasonal patterns as that of acute watery diarrhoea.
Mode of Transmission
Most of the pathogenic organisms that cause diarrhoea and all the pathogens that are known to be major causes of diarrhoea in many countries, are transmitted primarily or exclusively by the faecal-oral route. FaecaI-oral transmission may be water-borne, food-borne, or direct transmission which implies an array of other faecal- oral routes such as via fingers, fomites or dirt which may be injested by young children.
Prevention and Control
Regardless of the causative agent or the age of the patient, the sheet anchor of treatment is oral rehydration therapy such as the one advocated by WHO/UNICEF.
The Diarrhoeal Diseases Control (DDC) Programme of WHO has been launched in 1980. The programme has advocated several intervention measures to be implemented simultaneously with mutually reinforcing and complementary impacts. These measures centre round the widespread practice of "oral rehydration therapy".
- Oral Rehydration Therapy : With introduction of oral rehydration by WHO it is now firmly established that oral rehydration treatment can be safely and successfully used in treating acute diarrhoeas due to all aetiologies, in all groups and in all countries. The aim of oral fluid therapy is to prevent dehydration and reduce mortality. Oral fluid therapy is based on the observation that glucose given orally enhances the intestinal absorption of salt and water and is capable of correcting the electrolyte and water deficit.
Initially the composition of oral rehydration salt (ORS) recommended by WHO was sodium bicarbonate based. Inclusion of trisodium citrate in place of sodium bicarbonate made the product more stable and it resulted in less stool output especially in high-output diarrhoea as in cholera, probably because of direct effect of trisodium citrate in increasing intestinal absorption of sodium and water.
More recently an improved ORS formulation has been developed which not only is as safe and effective as the original in preventing and treating diarrhoeal dehydration, but also reduced stool output or offers additional clinical benefit or both. It is focussed on reducing the osmolarity of ORS solution to avoid possible adverse effects of hypertonicity on net fluid absorption by reducing the concentratIon of glucose and sodium chloride in the solution.
Recommended formulation of ORS: Because of the improved effectiveness of reduced osmolarity ORS solution, WHO and UNICEF are recommending that countries manufacture and use the following formulation in place of the previously recommended ORS solution. Since January 2004, the new ORS formulation is the only one procured by UNICEF. India was the first country in the world to launch this ORS formulation since June 2004
Composition of reduced Osmolarity ORS
| Reduced Osmolarity ORS
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grams / litre
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Sodium chloride
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2.6
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Glucose, anhydrous
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13.5
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Potassium chloride
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1.5
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Trisodium citrate dehydrate
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2.9
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Total weight
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20.5
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Guidelines for assessing Dehydration:
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Parameter
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Dehydration
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Mild
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Severe
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1.
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Patient’s appearance
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Thirsty, alert, restless
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Drowsy, limp, cold, sweaty, may be comatose
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2.
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Blood pressure
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Normal
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Less than 80 mm Hg, may be unrecordable
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3.
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Skin elasticity
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Pinch retracts immediately
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Pinch retracts very slowly
(more than 2 seconds)
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4.
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Tongue
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Moist
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Very dry
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5.
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Ant. Fontanelle
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Normal
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Very sunken
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6.
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Urine flow
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Normal
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Little or none
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- Better Much Care Practivces
- Material Nutrition : Improving prenatal nutrition will reduce the low birth weight problem. Prenatal and postÂnatal nutrition will improve the quality of breast milk.
- Child Nutrition:
- promotion of breast-feeding: The breast-fed child is at very much less risk of severe diarrhoea and death than the bottle-fed child.
- Appropriate weaning practices: Poor weaning practices are a major risk for diarrhoea. The child should be weaned at appropriate time. In any case exclusive breast feeding for sixth month of life should be followed. The weaning foods should be prepared hygienically using nutritious and locally available foods.
- Supplementary feeding: This is necessary to improve the nutritional status of children aged 6-59 months. As soon as the supplementary food is introduced, the chiId enters high-risk category.
- Preventive Measures: includes
- Sanitation
- Health Education
- Immunization
- Fly control
- Prevention of Diarrhoeal Epidemics: this can be achieved through primary health care services. The primary health care involves delivery of a package of curative and preventive services at the community level.
- Diarrhoeal Control Program in India: The Diarrhoeal Disease Control Programme was started in 1978 with the objective of reducing the mortality and morbidity due to diarrhoeal diseases. Since 1985-86, with the inception of the National Oral Rehydration Therapy Programme, the focus of activities has been on strengthening case management of diarrhoea for children under the age of 5 years and improving maternal knowledge related to use of home available fluids, use of ORS and continued feeding. From 1992-93, the programme has become a part of the Child Survival and Safe Motherhood Programme and all activities are now integrated with those of the CSSM Programme.
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Participants