BackgroundVarious studies showed that chemotherapy can control schistosomiasis morbidity, but association of measures (water supply, sewage disposal and increase of socioeconomic conditions) is necessary for transmission control.Methodology/Principal FindingsA survey dealing with socioeconomic conditions, snail survey, contact with natural waters, and clinical and stool examinations was undertaken at an endemic area in the State of Minas Gerais, Brazil. The methodology used was the same for both evaluations (1981 and 2005). Four hundred and seventy-five out of 1,474 individuals studied in 1981 could be contacted. From these, 358 were submitted to stool examination, and 231 of them were clinically examined. Patients eliminating S. mansoni eggs in their stools were treated. The results showed that the prevalence rate in Comercinho, a municipality of the State of Minas Gerais, Brazil, was substantially reduced to 70.4% and 1.7% in 1981 and 2005, respectively, as well as the frequency of the hepatosplenic form (7% to 1.3%) after five treatments effectuated between 1981 and 1992. No other new case of this form was detected from 1981 onwards. Another important aspect to be considered was the improvement of people's living standard that occurred in the region after more than two decades' efforts (better housing, professional skill and adequate basic sanitation).Conclusion/SignificanceThe control of morbidity and very significant decrease of schistosomiasis transmission in an area until then considered as hyperendemic was possible by means of association of successive specific treatments of the local population, together with the construction of privies, water supply in the houses and improvement of socioeconomic conditions.

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In practice, chemotherapy is the main measure utilized for the control of schistosomiasis in endemic countries. The schistosomicidal drugs used, oxamniquine and praziquantel, present few side effects and a high schistosomicidal activity, thus contributing for the treatment of infection, as well as for the control of morbidity and transmission of the disease. In the 1970s, oxamniquine was very used for individual and mass treatment of schistosomiasis, presenting satisfactory results regarding efficacy and tolerance (Katz 1980). At the end of that decade, praziquantel became available for the treatment of schistosomiasis, showing good therapeutic activity and also few side effects as well. Praziquantel is now the drug of choice for the treatment of the disease caused by the three main species of the parasite that infect humans (Doenhoff et al. 2002). Taking into account the possible rise of resistance to treatment, the tolerance level of the worm to the drug, and the therapeutic failures, it is very important to search for new therapeutic alternatives for schistosomiasis. This search is now imperative, especially considering the possible interruption of oxamniquine production as a result of its higher cost, when compared to praziquantel.The association of different drugs for use in the therapeutics of various infectious diseases can serve as a mechanism to avoid, or to delay, the rise of drug resistance. In the present study, in vivo and in vitro trials were carried out on the efficacy of the treatment with lovastatin against the Schistosoma mansoni adult worms, when administered in association with oxamniquine or praziquantel in the mouse model.