Avaliaçäo do programa de controle da esquistossomose (pce/pcden) em municípios situados na Bacia do Rio Säo Francisco, Minas Gerais, Brasil / Evaluation of the control on schistosomiasis (PCE/PCDEN) in the municipalities of the region of Säo Francisco river, Minas Gerais, Brazil

ABSTRACT

An evaluation of the control program on schistosomiasis (PCE/PCDEN) was performed in the region of Säo Francisco river in MInas Gerais. The study area comprises six municipalities, with 130,000 inhabitants and 916 localities situated in an area with 10,722 km2. The activities initiated in 1983-85 in four municipalities and in 1987 in the other two. The main measures of control were repeated treatment with oxamniquine and use of niclosamide. The prevalence of infection by Schistosoma mansoni in the first four municipalities, that was initially around 18 and 32 per cent, dropped abruptly after the first intervention (1983/85) and remained in levels below the initial ones until the last assessment (1990-94); similar trends were observed for the proportion of infected snails. In these municipalities, the proportion of localities without infection or with prevalence below 5 per cent increased in relation to those with higher prevalence. In the other two municipalities, with initial prevalence below 5 per cent, there were no substantial changes in S. mansoni prevalence or proportion of infected snails; the cost benefit of the program in these municipalities need to be assessed and the priorities redirected to eradicate focal areas and prevent spread to non infected localities. The authors call attention to the difficulties in the long term of a control program based on repeated treatments. Information on factors associated with S. mansoni infection in each locality, or in groups of similar localities, would allow to develop additional measures to treatment that could last longer and be less dependent on the continuous use of chemotherapy.