PREVALENCE OF VIBRIO-CHOLERAE AND SALMONELLA IN A MAJOR SHRIMP PRODUCTION AREA IN THAILAND

In 1992 and 1993, a 7 months study was carried out in a major shrimp- producing area in Southern Thailand to study the prevalence of Vibrio cholerae and Salmonella. A total of 158 samples were examined includin g water, sediment, shrimp, pelleted feed, shrimp gut, and chicken manu re. Salmonella was not recovered from any sample type studied. V. chol erae O1 was isolated from 2 (2%) and V. cholerae non-O1 was isolated f rom 35 (33%) of 107 samples examined. The occurrence of V. cholerae wa s not significantly influenced by water salinity, temperature, dissolv ed oxygen or pH. There was no correlation between fecal coliform count s and the prevalence of V. cholerae. The results indicate that V. chol erae non-O1 is ubiquitous in aquatic environments where shrimp culture is practised under a variety of environmental conditions. The public health significance of non-O1 V. cholerae in shrimp culture remains to be determined. V. cholerae O1 and Salmonella do not appear to constit ute a hygienic problem even if chicken manure was used as fertilizer.