In an operational research on the improvement of sanitation and water supply by an Indo-Dutch project at Mirzapur, UP, diarrhoeal morbidity was taken as an intermediate outcome variable for measuring the impact of the proposed intervention. In this study 350-410 under-five children were selected from 200 urban families of 3 slums and surveyed during 3 different seasons for 2 weekly recall of morbidity, treatment and feeding practices during diarrhoea. The prevalence of diarrhoea varied between 8.7% to 33%. Breast feeding was not restricted while other forms of feeding was continued in 57.1% to 66.3% of cases. Use of ORT increased significantly from 0% to 39.62% possibly as a result of health education. Reorientation of private practitioners to avoid use of unnecessary drug is suggested.

During the epidemic of bacillary dysentery at Agartala, Tripura, a total of 62 hospitalized patients suffering from diarrhoeal diseases were studied during the later part (11-16 June, 1988) of the epidemic. Principal features of Shigellosis cases were discussed. Of these 62 cases investigated, 19(30.6%) cases had the mucoid diarrhoea. From them S.dysenteriae type 1 and S.flexneri had been recovered from 31.6% and 10.5% cases, respectively. All the strains of S.dysenteriae type 1 isolated during the period of investigation were resistant to nalidixic acid.

An out break of acute bacillary dysentery in a village called Dhamasin in Hooghly district of West Bengal was investigated during March 1984. Forty seven percent of families were affected. A total of 91 cases and 2 deaths occurred amongst 937 people giving an over all attack rate of 9.7% and a case fatality rate of 2.2 percent. Highest attack rate (22.7%) was observed in below one year age group. Multiple drug resistant Shigella dysentery type 1 strains were isolated for the first time from 6 out of 22 cases sampled at the domiciliary level. The organism was never isolated earlier during last ten years of surveillance in the infectious Diseases Hospital, Calcutta. Identification of nature of this outbreak and it's causative agent helped to realise the potentiality of extensive spread and paved the way for further investigations. Public health authorities were buffled as the rapid spread of the disease throughout the entire state of West Bengal could not be contained in spite of instituting all probable control measures on war footing.

Since diarrhea is responsible for considerable morbidity and mortality in India as well as in developing and developed countries, public health specialists strive to develop vaccines against various pathogens which cause diarrhea. Rotavirus (RV) causes 20-40% of severe diarrhea among 6-24 month olds. So they hope for a single dose vaccine against all 4 RV serotypes which can be administered to newborns, but such a vaccine does not yet exist. The bovine and rhesus vaccines are the only heterologous candidate vaccines available, (as of the end of 1989). Another candidate vaccine is the human-animal reassortant RV vaccine where scientists incorporate the VP7 surface protein of human RV into animal RV. The 3rd type of RV candidate vaccine include the naturally attenuated human RV (nursery strains). Vibrio cholerae also causes significant diarrhea in India. Researchers have conducted field trials of many cholera vaccines since the mid 1990s, but they could not find a vaccine which could be used for mass vaccination against cholera. In fact, the cholera vaccine currently used only provides 50% protection, lasts 3-6 months, does not affect carriers, and does not protect against all strains. Salmonella typhi also causes diarrhea, especially among school age children and young adults. The results of large scale field trials in the 1960s reveal that 2 doses of the acetone inactivated typhoid vaccine performed the best of the injectable killed whole cell vaccines. In fact, it provides 79-93% protection and lasts 3-4 years. Further the live oral Ty21a lyophilized vaccine reconstituted in a liquid form and given in multiple doses provides comparable protection (71-96%) against typhoid as well as some protection against paratyphoid. Moreover they induce no side effects. Shigella species also cause diarrhea, especially in children. Various candidate vaccines against shigellosis include the spontaneously attenuated vaccines, streptomycin dependent vaccines, toxoid against exotoxins, and mutant hybrid strains.

Oral rehydration therapy (ORT) prevents severe morbidity and death from mild to moderate dehydration from acute diarrhea for all ages and all etiologies. WHO advises ORT fluid to contain 3.5 g sodium chloride, 3.5 g potassium chloride, 2.5 g sodium bicarbonate or 2.9 g trisodium citrate dihydrate, and 20 g glucose all dissolved in 1 1 of water. This fluid does not reduce stool volume or frequency and does not curtail duration thus it is not always acceptable. Improved ORT is needed, however. The glucose concentration cannot be increased above the present 2% since an increased concentration would intensify diarrhea and dehydration. Researchers are working on an improved solution (Super ORS) which would rehydrate the body and actively bring on reabsorption of endogenous secretions in the intestine. Thus this improved ORS would reduce stool volume, shorten duration of diarrhea, and allow early introduction of feeding. Even though some studies demonstrate that fortified ORS with the amino acid glycine decreases stool volume by 49-70% and duration of diarrhea 28-30%, other studies indicate that it induces excess sodium concentrations in the blood. 1 study demonstrates that in comparison with the standard ORS, ORS fortified with the amino acid L-alanine reduced the severity of symptoms and the need for fluid in patients afflicted with cholera and enterotoxigenic Escherichia coli. Further studies reveal that rice powder based ORS (50-80 g/l) reduces stool volume 24-49% and duration of duration 30%. The advantage of using rice is that when it hydrolyzes glucose, amino acids, and oligopeptides emerge. Each 1 of these chemicals facilitate sodium absorption through separate pathways. Disadvantages include the fuel must be used to cook the rice, rice based ORS ferments within 8-24 hours making it useless, and the rice or pop rice needs to be ground.

Before 1970, laboratory staff could not only identify the causative organism of acute diarrhea in 20% of cases, but in 1990, they could identify it in 80% of cases. These organisms are either bacteria, virus, or parasites. The bacteria include enterotoxigenic bacteria (Vibrio cholerae, enterotoxigenic Escherichia coli, Clostridium perfringens, and Staphylococcus aureus) and enteroinvasive bacteria (Campylobacter jejuni, C. coli, and Salmonella and Shigella species). The leading cause of death in diarrhea patients is dehydration. Oral rehydration solutions (ORS) can alleviate mild and moderate dehydration regardless of the etiology of the diarrhea or the age of the patient. WHO recommends an ORS containing glucose and various electrolytes which permit salt and water absorption in many cases of acute diarrhea. Due to the possibility of excess salt entering the bloodstream (hypernatremia), some pediatricians do not use the WHO recommended ORS in newborns and young infants. Instead they use 2 parts ORS followed by 1 part water. This treatment is not easy for illiterate mothers to follow, however. Continued breast feeding during diarrheal episodes along with administration of ORS protects not only against dehydration, but also hypernatremia. ORS should not be administered in severe case of dehydration, however. Medical personnel need to administer replacement fluid such as Ringer's Lactate solution intravenously regardless of the age group. Once the initial deficit has been controlled, ORS administration and reintroduction of foods can follow. Antibiotics should only be administered if the medical personnel suspect severe cholera in an endemic area (tetracycline and furazolidone); shigellosis, but 1st the bacteria must be tested to see if the strain is multiple drug resistant (ampicillin, trimethoprim-sulphamethoxazole, furazolidone, nalidixic acid), and acute amebiasis or giardiasis (metronidazole and tinidazole). Antidiarrheals should not be used.

This communication is an attempt to review the status and implementation of the Oral Rehydration Therapy in the programme for Control for Diarrhoeal Diseases. The Global and the Indian situations are separately discussed, with more emphasis on the latter. Use of Home Available Fluids (HAF), Salt Sugar Solution (SSS). Commercial packets of ORS and the Government supplied packets of ORS are also assessed.

Two decades of research have established newer pathogens and techniques in establishing several organisms of diarrhoeal diseases as aetiological agents. It is now possible to detect an agent in 80% of the situation of diarrhoea in a standard laboratory. The brief review describes the list of pathogens, their diagnostic techniques with short description on clinical and epidemiological status.

An outbreak of acute diarrhoeal disease between August and October 1985 in 3 districts of Manipur state was investigated amongst 9,29,077 population at risk. The overall attack rate and case fatality rate were 0.2% and 0.9% respectively. Hospital records revealed that 58.8% of cases occurred amongst older children above 5 years of age. V.cholera was isolated from 25.3% of cases sampled. Interestingly, increased frequency in weekly admission of cases amongst children during first two years of life increased in the beginning of October when the original peak of diarrhoeal outbreak was about to decline. The October peak was caused by rotavirus which could be detected from 50.0% of diarrhoeal children in this age group. This possibly reflected beginning of the usual rotavirus diarrhoea season in the locality.

Researchers followed 90 households (445 people) in Sunderpur slum in Varanasi in Upper Pradesh, India for 1 year and collected stool samples when people were ill with diarrhea to determine diarrhea incidence and causes of diarrheal disease. The water supply consisted of a well, public tap, or house tap with 30 households in each group. They noted 106 diarrheal episodes for an incidence of around 23%. Incidence decreased significantly with age (p.001). For example, it was 62.9% for children 5 years old, 34% in the school age population, and 8.7% in people =or 15 years old. Improved resistance to infection and/or improved personal hygiene could have accounted for this difference. Diarrheal incidence was considerably lower in the autumn (9.3%) and winter months (11.1%) than the spring (49.1%) and summer months [rainy season] (30.5%) (p.001). Researchers found at least 1 parasite in the stool sample of 81.5% of cases. The leading causative agents included Ascaris lumbricoides (42.1%), Entamoeba histolytica (35.2%), hookworm (7.9%), and Escherichia coli (5.7%). Diarrhea incidence was much higher in persons whose water supply was a well (35.8%) compared to 23.2% for those with a public tap, and 12.8% for those with a private tap. These results concerning the water supply corroborated those of the Planning Research and Action Institute's (Upper Pradesh) pilot piped water supply program in the areas of Banki, Parendra, and Mokhampur in which incidence was highest in Banki where the water supply was an open well. The next highest and the lowest incidences were among those whose water supply consisted of public taps and private taps respectively.

An extensive outbreak of acute gastroenteritis involving all age group of patients occurred during July-September, 1978 in the Central district of Manipur state. A total of 4469 cases occurred during the period. 45.7% of diarrhoea cases sampled and 47.6% of water samples collected from rivers were found to be positive for V.cholerae biotype EITor. Case fatality rate in this epidemic was exceptionally low (0.8%) which was attributed to the early domiciliary use of oral rehydration salt solution (ORS) in the affected villages. Utility of ORS in drastic reduction of case fatality rate during any epidemic situation was first of its kind in the Indian scene.