[Evolution of the prevalence of Mansonia schistosomiasis in the district of São Luis do Maranhão (Brazil) between 1978 and 2001].

This is an approach on the prevalence of the Mansonia schistosomiasis in the city of São Luís, capital of the State of Maranhão, over the last 23 years, assessed in the face of the control actions implemented during this period. The research was performed through data obtained in the annual reports of the Fundaçào Nacional de Saúde (National Health Foundation) - FUNASA/MA, from 1978 to 2001. Fourteen locations have been selected as follows: Areinha, Barreto, Camboa, Coroadinho, Coroado, Diamante, Fé em Deus, Floresta, Matadouro, Monte Castelo, Piancó, São Francisco, Vila Embratel and Vila Passos, whose prevalence was >or=4%, in at least one year of the period studied. In the 1980s, the prevalence was higher. It has to be highlighted that in all locations the level of prevalence underwent important oscillations during the evaluation year. It is an active search for cases and positive treatment, as well as sanitation works, determined the drop of prevalence in most of the locations at the end of the last decade.