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To evaluate the effectiveness of potash alum in purifying household water, this study was carried out in a suburban community in Yangon, Myanmar. It was designed to test whether the application of potash alum (0.05%) regularly into household water storage vessels during water replenishment was capable of decontaminating household water in homes using shallow well water. It was conducted in 100 households (50 each in intervention and control groups). After alum (0.05%) was added, the contamination level of water decreased on the 2nd and 3rd days. The alum-treated water was well tolerated by the users; only one member complained of a metallic taste. We conclude that potash alum was effective and acceptable in this community in decontaminating household water.

Virulence properties of the environmental isolate of vibrios from natural waters of Yangon, Myanmar were studied. Vibrio spp. were isolated for identification by the membrane filtration method and cultured on thio-sulphate-bile-sucrose media. No Vibrio cholerae O1 were isolated. V. cholerae non-O1 were the major vibrio species isolated from the samples. None of them were detected for cholera-toxin-like toxin, thermostable direct haemolysin, or heat-stable enterotoxin. Sixty-one isolates gave haemolytic activity; 27 V. cholerae non-O1 and 6 V. fluvialis isolates produced protease.

To isolate major bacterial pathogens from children's food and drinking water, a 3-month study was conducted in a suburban community in Yangon, Myanmar. From the morning meals and stored drinking water of 208 randomly selected children, 775 food and 113 water samples were collected and were cultured using standard methods. Escherichia coli, Vibrio cholerae non-01, and Salmonella were isolated from 505, 28 and 6 food samples respectively, and E. coli and V. cholerae non-01 were isolated from 29 and 5 water samples respectively. Among the E. coli isolates, 8 produced heat-stable toxin (ST) and 3 were enteroinvasive. Nine V. cholerae non-01 produced cholera-like toxin. Of the 29 E. coli isolates from the samples of drinking water, 3 produced ST. All water samples were negative for Salmonella. The study underscores the importance of bacterial contamination of children's food and drinking water and stresses the need to improve environmental sanitation.

The association between contamination of morning samples of food and water of 208 children aged 6-29 months and the incidence of diarrhoea was investigated for 3 months in Yangon, Myanmar. Contamination of the samples was determined by isolation of faecal coliforms (FC) by standard methods. The children were divided into three groups, high, medium and low, according to the proportion of food and water samples found to be contaminated. The incidence of diarrhoea was recorded by weekly recall. Of the 779 food samples, 504 (65%), and of the 860 drinking water samples, 187 (22%) were positive for FC. The association between food and water contamination and the incidence of diarrhoea was assessed by comparing the cumulative incidences in the high and medium groups with that in the low group which served as reference. Diarrhoea risk ratios (RR) for children in the medium and high contamination groups (food, RR = 1.04 in medium and 0.78 in high vs 1 in low; water, RR = 0.73 and 0.73 vs 1) were not significantly different from those who were in the low-contamination group even after controlling for the confounding variables.

To determine the degree of faecal contamination of currency notes, samples of the notes that were in circulation in a local market in Rangoon were collected and examined bacteriologically to count the number of the total bacteria and faecal coliforms (TC, FC) using standard methods. TC and FC ranged from 0 to 2.9 X 10(7)/sq cm of currency notes and the isolation rates of pathogens increased during the hot wet season. Enteric pathogens, such as enterotoxigenic Escherichia coli, Vibrio, and Salmonella were isolated from paper-money samples obtained from butchers and fish mongers. The study suggests that currency notes may carry enteric pathogens.

The carriage of enteric bacterial pathogens by house flies, caught from different places of human habitation and at different seasons, was quantitatively determined in the town of Tamwe, Yangon, Myanmar. A total of 186 fly-pools, each containing 10 live flies, were caught in entomological cages by random sampling regarding season, month, frequency and place of collection. A 10% suspension of each homogenised fly-pool in sterile normal saline was prepared on the day of collection and was cultured to isolate pathogens using standard microbiological methods. Escherichia coli, Vibrio cholerae non-O1, and species of Salmonella and Shigella were isolated from 76.3%, 45.7%, 11.8% and 4.8% respectively from all the fly-pools. Enteric bacterial pathogens were isolated more frequently in flies from refuse dumps and animal pens and least commonly in flies from kitchens. Of the E. coli isolates, one pool each from flies trapped in animal pens (n = 30 fly-pools), latrines (n = 32) and refuse dumps (n = 34) produced enterotoxins (ETEC). These ETEC isolates were obtained in the months of June and July. The rates of isolation of pathogens were highest in the hot-wet season. The faecal coliform counts in the fly-pools also increased in this season compared with those in cool-dry and hot-dry seasons. These data suggest that flies may be an important carrier of enteric infections in Myanmar.