St Lucia revisted: the status of schistosomiasis mansoni in 1996, 15 years after the end of the St Lucia project - abstract

ABSTRACT

Schistosoma mansoni, the only species of schistosome to infect humans in the Western Hemisphere, is currently known to exist in the Caribbean islands of Antigua and St Lucia. The current status of the trematode in these islands has not been investigated for many years. The recent completion of the John Compton Dam, which provides water for the capital, Castries, and expanding developments in the north of St Lucia provided impetus for this study. The current epidemiological study examined hospital and diagnostic laboratory records for sentinel data, carried out a limited cross-sectional prevalence semi-quantitative stool survey in school children and investigated the infection rate in known residual intermediate snail host populations. These data were augmented by ongoing stool and snail surveys. The results indicate that the advances made in the reduction of the human prevalence (40 percent to 5 percent) of S. mansoni during the 16 years of the St Lucia project (1965 - 1981) have been maintained. The residual Schistosoma mansoni population is currently estimated to be more than 3 to 5 thousand people (2.7 - 4.5 percent of the population). Residual populations of Biomphalaria glabrata persists, but are confined to restricted mountain habitats and infected snails have not been reported since 1984. Control measures, that have been implemented by the St Lucia government during the 15 years since the Rockefeller-sponsored project ended, included treatment of infected people and limited environmental and snail control measures. Current plans are to continue surveillance but the development of the dam and the current low prevalence suggest that it may be appropriate at this time for a more aggressive approach and a plan for eradication of the parasite is suggested.(AU)