Five types of Escherichia coli are responsible for as much as 25% of all diarrheal diseases in developing countries. They tend to be transmitted via contaminated foods, particularly weaning foods, and water. They include enterotoxigenic, enteropathogenic, enteroadherent, enteroinvasive, and enterohemorrhagic E. coli. Shigella species are responsible for 10-15% of acute diarrheas in children less than 5 years old and the most common etiologic agents of childhood dysentery. Shigellosis is common in the warm season. An outbreak of shigella dysentery in West Bengal, India, had a high attack rate in children less than 5 years old and was resistant to many drugs. Nontyphoid Salmonella species cause watery diarrhea with nausea, cramps, and fever. Worldwide, various Salmonella strains exhibit resistance to ampicillin, chloramphenicol, and co-trimoxazole. Campylobacter jejuni produces watery diarrhea which, in 33% of cases and 1-2 days after onset, contains blood and mucus. Many normal healthy children in developing countries are carriers of C. jejuni. Vibrio cholerae O1 is endemic in parts of Africa and Asia (e.g., 5-10% of hospitalized diarrhea patients). The ElTor cholera biotype is responsible for the 7th pandemic. Other bacterial enteropathogens are Aeromonas species, Bacteroides fragilis, and Providencia alcalifaciens. Rotavirus is a major cause of sporadic and epidemic diarrhea among 6-23 month olds. Its incidence peaks in cold or dry seasons. Other viral enteropathogens are Norwalk virus, adenoviruses, astroviruses, and coronaviruses. In India, the prevalence of Entamoeba histolytica varies from 3.6% to 47.4%. It occurs equally in high and low socioeconomic classes. Giardia lamblia usually infects 1-5 year old children. Its transmission routes are food, water, and the fecal-oral route. Cryptosporidia produce acute watery diarrhea, especially in children less than 2 years old. Cryptosporidia diarrhea is common among AIDS patients. Oral rehydration therapy and proper feeding during and after diarrhea reduces deaths from diarrhea.

Before oral rehydration therapy (ORT) was developed, intravenous fluid therapy was the mainstay of fluid therapy for diarrheal dehydration. The following early observations, however, formed the scientific basis for the discovery of ORT: a group of physiologists observed that glucose enhances the absorption of sodium and water across the intestinal brush-border membrane of experimental animals and that no morphological changes occur in the gut epithelium of cholera patients. Captain Phillips of the US Army in 1964 first successfully tried oral glucose saline on two cholera patients. Following this, scientists working at the Cholera Research Laboratory, Dhaka, and the Infectious Diseases Hospital, Calcutta, contributed to the development of modern oral rehydration salt (ORS) solution. The efficacy of standard ORS was first demonstrated by Pierce et al and others during 1965-69. During the Bangladesh liberation war, Dr. Dilip Mahalanabis showed the efficacy of ORS in cholera cases among Bangladeshi refugees (1971-72) and Sircar et al in 1978 demonstrated the efficacy of ORS in a cholera epidemic in Manipur. De et al in 1974 and Chatterjee et al in 1978 convincingly demonstrated the efficacy of ORS in children with diarrhea including cholera. Based upon this information, the World Health Organization in 1978 launched the global diarrheal diseases control program with ORS at its heart and the short-term objective of reducing mortality due to diarrhea. The safety and efficacy of WHO-ORS containing 90 mmol/liter of sodium for neonates was not demonstrated until 1979 at which time Dr. Daniel Pizarrow and colleagues showed the WHO-ORS was effective even for neonates with dehydrating diarrhea and safe if used along with plain water in a 2:1 regimen. To avoid confusing illiterate mothers in developing countries, Dutta et al and Roy et al in 1984 reported the safety and simplicity of uninterrupted breastfeeding together with breastfeeding. Further findings were produced on the optimal salt content of ORS for severely malnourished children. Studies with their corresponding findings have continued since then, with current efforts focused upon developing a treatment for diarrhea using the role of short chain fatty acids in acute watery diarrhea.

Diarrhea is one of the most common causes of morbidity and mortality in infants and children less than 5 years old in developing countries. Diarrheal diseases are a major cause of childhood malnutrition. Toxin-producing bacteria are responsible for many acute diarrheas. Oral rehydration solution (ORS) treats dehydration caused by acute diarrheal episodes. WHO promotes the use of a single oral rehydration formula which contains 3.5 g sodium chloride, 2.5 g sodium bicarbonate or 2.9 g trisodium citrate dihydrate, 1.5 g potassium chloride, and 20 g glucose to 1 liter of water. This ORS formula can safely be used for all age groups and all etiologies of diarrhea. ORS replaces the lost fluid and electrolytes and maintains fluid and electrolytes. Pediatricians in most developed countries do not accept this ORS formula in cases of rotavirus-caused diarrhea because rotavirus blunts some absorptive villi and reduces the activity of lactase and other disaccharidase, resulting in reduced absorption. Yet, the unaffected villus cells may absorb enough water and electrolytes to be effective. In cases of vomiting, ORS should be administered in small amounts and slowly. Some health workers are concerned that 90 mmol/l sodium in the WHO formula causes hypernatremia in neonates and young infants who have low sodium levels in their stools. Specialists suggest ORS with 30-60 mmol/l or additional water administered in a 2:1 ratio for these young infants. Hypernatremia is also a concern for malnourished children, but studies show that WHO's ORS is safe and effective in treating malnourished children. Bottle fed children are more vulnerable to hypernatremia than breast fed children. Hypernatremia has neurological effects. Hyponatremia is more common in developing countries than developed countries. It also has neurological effects. In severe dehydration cases, intravenous fluid or ORS delivered via a nasogastric tube should be given immediately.

The review of the current status and implementation of Oral Rehydration Therapy at the community level have been presented in this communication with special emphasis on its development, ORS access rate, ORS use rate and home available fluids. The global ORS supply has gone up an increased eleven folds since 1981. Similarly the ORS access rate has also increase from 46% to 68% in 1991. However, the global ORS use rate was low (21%). The major constraints during ORT implementation which have been reported by several scientists are also discussed.

A study was conducted to find out the pattern of food and fluid practices during diarrhoea among 2,160 children under five. Mothers were educated to give home made fluids during diarrhoea. Their personal hygiene was studied and a positive correlation between diarrhoea and poor personal hygiene was found. After the health education programme, it was observed that mothers started giving home made fluids to the children during diarrhoea but the amount was not increased. Normal feeding was continued only in 38.2% of the episodes.

A community based study was conducted to assess the magnitude of the problem of diarrhoea and factors associated with it amongst children below three years of age. Two districts in Haryana state were selected by using multistage random sampling procedure. Eight hundred eighteen children in the age group of 0-35 months belonging to scheduled caste communities were studied. All children suffering from diarrhoea at the time of survey or within last 2 weeks were included for the detailed study. The occurrence of diarrhoea was highest in age group 6-11 months (28%) and was lowest in age group 0-5 months (16%). No relationship was found between the nutritional status of children and the occurrence of diarrhoea. The percentage prevalence of diarrhoea was 42, 32 and 36 per cent amongst normally, moderately and severely malnourished children, respectively. Thirty seven percent of children suffering from diarrhoea received bottle feed.

One thousand thirtynine infants, 794 children in their second year of life and 445 children in their third year of life were followed up longitudinally from April 1984 to March 1985. Nearly 6 episodes of diarrhoea per annum, during infancy, 5.49 episodes in second and 4.19 episodes during third year of life respectively, were experienced. On an average, each episode of diarrhoea lasted for four days. 20% of infants, 6.43% of children between 1-2 years and 7.26% of children between 2-3 years, experienced weight loss of 300 gm. or more following episode of diarrhoea. Diarrhoea case fatality rate was 1.8% and 0.75% for infants and children between 1-3 years of age respectively. Home management of diarrhoeas by mothers with the advocacy of anganwadi workers and health workers yielded dividends. Sustained efforts of this kind may go a long way in management of diarrhoeas.

During an operational research study on implementation of oral rehydration therapy in a block of West Bengal, India, amongst a population of 2, 16,805, a total of 171 Community Health Guides and 152 Anganwadi Workers were initially trained for one working day by lectures and slides about diarrhoea case management at the community level. The training was evaluated after two months and found to be inadequate. The workers were then retrained with modern approach using a module (prepared in local language) as suggested by World Health Organisation. The level of retention of the imparted knowledge of Health Workers for different items 2-3 months after training with lectures and slides ranged between 5-25% except preparation of ORS which was 80%. With the use of modules, 47-98% of health workers could retain the same knowledge 3 months after the training. The knowledge thus acquired were sustained even after 12 months of training to a level which was still much better than that retained 2 months after training with slides and lectures. However some of the items like indication of use of Home Available Fluids, dosage of ORS and when to refer a diarrhoea case to health facility were more difficult to recall after one year. This possibly indicates need for in-service training of grassroot level health workers at suiTable interval.

Use of ORT is saving 1 million diarrhoeal deaths each year among children. C.S.S.M. programme aims at preventing 70% diarrhoeal deaths, through widespread use of ORT. The present study was carried out to find out the extent of the problem of diarrhoea and utilisation of ORT in three districts of West Bengal. The results showed that the utilisation of ORT was 80.8%, 70.7% and 65% in Howrah, Hooghly and 24-Parganas (South) respectively, during attacks of diarrhoea. The continuing feeding rates were 60.1%, 62.7% and 55.5% in Howrah, Hooghly and 24-Parganas (South) respectively.

In India, epidemiologists followed 980 rural families with children less than 3 years old living near Calcutta in West Bengal to identify determinants related to maternal behavior and feeding practices of childhood diarrhea. They identified 570 families with diarrhea cases and 410 families with no diarrhea cases. Children with diarrhea were more likely to live in Kuchcha housing (44.7% vs. 33.9%; p = 0.0006), to have a family income of less than Rs.500/month (44.2% vs. 36.6%; p = 0.016) and a mother who was illiterate (53.5% vs. 45.4%; p = 0.013). Nondiarrheal families were more likely to have a sanitary latrine (63.9% vs. 50.5%; p = 0.000031) and have soap (for ablution, 22.9% vs. 14.4%; p = 0.0005 and, before food handling, 7.1% vs. 3%; p = 0.0046). Mothers with children who did not have diarrhea were more likely to space their births at least 4 years apart than those with children who did have diarrhea (20.5% vs. 14.7%; p = 0.018). Mothers with children who did not have diarrhea were also less likely to practice poor hygiene. Specifically, they would tend not to use leftover food for the next feeding (19.1% vs. 38%; p = 0.02), to have children whose body and clothes were dirty (19.1% vs. 40%; p = 0.01), to dispose of stools indiscriminately (55.3% vs. 73.7%; p = 0.02), to share a common latrine with other villagers (15.9% vs. 36.2%; p = 0.008), and to stop drinking water in a wide mouth container (66% vs. 84.8%; p = 0.008). Mothers with children who did not have diarrhea were also more likely to wash the container used for feeding the children with soap (48.9% vs. 30.4%; p = 0.03).

An analysis of hospital admission records and case histories from 1989 to 1993 and interviews with hospital administrators, physicians, and mothers of hospitalized patients were conducted to examine the benefits of establishing the Diarrhoea Treatment and Training Unit (DTU) in June 1991 at the Infectious Diseases Hospital in Calcutta, India. The case fatality rate of all diarrhea patients fell between 1989 and 1993 from 4.5% to 2.5%. Among patients less than 5 years old, it ranged from 12.7% in 1989 to 2.1% in 1992. The proportion of total cases successfully managed by using oral rehydration therapy (ORT) increased from 37% to 78.9% between 1991 and 1993. In 1989-1990, the hospital used 12,740 and 14,640 units of intravenous (IV) fluids. By 1993, it used only 7200 units of IV fluids. The use of packets of oral rehydration salts increased from 6000 in 1989 to 24,000 in 1993 (23,000 in 1993). Antibiotic use fell considerably (1989-1993, 100-31.5% of cases). The cost of treating each diarrhea patient decreased from Rs.84.50 to Rs.19.10. Before the DTU, the hospital did not allow mothers and other family members to stay with children who had diarrhea. Thus, young children could not be breast fed. Now, mothers stay with the children to administer ORT and to continue breast feeding. DTU staff train mothers in how to administer ORT and to continue it at home, to feed during and after diarrhea, and to recognize danger signs. These findings show that setting up the DTU reduced the case fatality rate of diarrhea patients and the cost of diarrhea treatment. They indicate the need to establish DTUs in major hospitals and ORT corners in all block primary health centers in the state.

Oral rehydration therapy (ORT) has simplified treatment of diarrheal dehydration. Hospitals in India have diarrheal treatment and training units (DTUs) to help manage the many diarrheal cases. DTU staff keep children for 4-6 hours to correct the dehydration with ORT and feeding. Health personnel undergo training in diarrhea management at DTUs. ORT is the preferred treatment in almost all cases of acute diarrhea. It is not best for diarrheal cases which exhibit shock, profuse vomiting (3 times/hour), glucose malabsorption, abdominal distension or paralytic ileus, and high rate of purging (15 ml/kg body weight/hour). ORT successfully treats 95% cases of infantile diarrhea, even Rotavirus-caused diarrhea. Health workers should begin treating cases of severe dehydration with intravenous (IV) therapy and then administer ORT 3-4 hours later for infants and 1-2 hours later for adults. If IV therapy is not possible, the patient should receive oral rehydration solution (ORS) nasogastrically and then referred to a facility with IV therapy. WHO's ORS formula is safe for newborns and young infants. ORT is appropriate even when diarrheal cases are vomiting. ORT tends to stop vomiting 1-2 hours after initial ORS administration because it corrects acidosis. The glucose in WHO's ORS facilitates absorption of adequate sodium across the intestinal mucous membrane. ORS also restores the loss potassium ions and HCO3/citrate. If ORS is not available, sugar salt solution can be used. To achieve the optimum concentration, the amount of sucrose has to be twice that of glucose. ORS should be stored in a cool place, be covered, and used for no more than 24 hours. Antiemetics should not be given during ORT. Most diarrheas do not require any antibiotic. Sterile water is not necessary to prepare ORS. Rice gruel, coconut water, and pulse water are home available fluids which can treat dehydration. Breast feeding and regular feeding should continue during diarrheal episodes.