[Schistosomiasis mansoni in Maranhão State, Brazil, 1997-2003].

The aim of this study was to assess the prevalence of schistosomiasis mansoni in Maranhão State, Brazil, from 1997 to 2003, based on data from the regional health offices included in the Schistosomiasis Control Program. The statistical method was polynomial regression. The municipalities (counties) of Bacabal and São Luís showed a constantly downward trend throughout the time series. Colinas showed an increase in prevalence until 2002, followed by a downward trend. Imperatriz witnessed a constant upward trend. Socioeconomic factors are highly significant for schistosomiasis prevalence in Maranhão, which helps explain the results. The recording of data for the regional health offices is believed to have been affected by changes resulting from decentralization of the Schistosomiasis Control Program. The study's results highlight issues that extend beyond analysis of the pattern of occurrence of schistosomiasis mansoni cases in the State of Maranhão, particularly demonstrating the need for improvements in the population's living conditions.