A socioecological approach to the control of Schistosoma mansoni in St Lucia.

Systematic observations of man/water contact in a valley endemic for S. mansoni in St Lucia were carried out prior to the introduction of a household water supply. The observations indicated that exposure of the population to cercaria-infested rivers and streams could be broken down into different types related to distinct and measurable domestic and economic activities. The number and duration of daily contacts with water played an important role in determining the relative risk of infection and correlated significantly with the number of infected persons by age in a survey conducted immediately following the observations. Consideration should be given to measuring and assessing the relative importance of different activities involving contact with water in relation to transmission and the formulation of control strategies.