Epidemiological study on contamination of water and diarrheal diseases in a rural community in northeast Thailand.

An epidemiological and bacteriological study of diarrheal diseases as well as the relation between domestic-use water and passage of enteric pathogens with stools of the villagers was performed in the northeastern rural area of Thailand on 4 different occasions during the 3 years from 1992-1994. The questionnaire study indicated that 93% of the residents used rain water stored in containers for drinking and other domestic uses, and that 28% of them filtrated and/or boiled the water before drinking it. About 90% of drinking water samples collected from the same residents showed positive responses for the preliminary test ofEscherichia coli contamination. Furthermore, a precise bacteriological survey indicated that more than half of the drinking water samples collected from containers storing rain water were contaminated with various enteropathogenic bacteria, includingE. coli, Vibrio spp. andShigella spp. The new serotype ofV. cholerae O139, synonym 'Bengal cholerae,' which could be isolated from different specimens, is replacing the traditional species ofVibrio. Forty-one per cent of the villagers carried enteropathogenic bacteria in their stools. Most of them were asymptomatic carriers and only a few of them showed clinical features of diarrhea. A few concrete propositions were discussed to supply safe water in these areas where drinkable underground water is not available.