CONTROL OF SCHISTOSOMIASIS-MANSONI IN RAVENA (SABARA STATE OF MINAS-GERAIS, BRAZIL) THROUGH WATER-SUPPLY AND QUADRENNIAL TREATMENTS

In this study, the results obtained in a control programme of schistos omiasis in Ravena (Sabara, Minas Gerais) between 1980 and 1992 are eva luated. Control measures used in this programme were: specific treatme nt of the people infected with Schistosoma mansoni at four year-interv als (1980/84/88) and the supply of tap water to 90% of the residences in 1980. A significant reduction of the prevalence (36.7% to 11.5% p l ess than or equal to 0.05) and of the intensity of the infection (228. 9 eggs per gram of feces (epg), s = 3.7 to 60.3 epg, s = 3.5, p less t han or equal to 0.05) was observed. No cases of the severeform of the disease were diagnosed in the area. Factors independently associated w ith the infection were in 1980 daily sand extraction and the lack of t ap water in residences and in 1992 daily sand extraction and fishing a nd weekly swimming. Concluding, the supply of tap water together with quadrennial treatments significantly diminished both the prevalence an d intensity of the S. mansoni infection, with the additional gain of p ersistent low indices even after four-year intervals between the treat ments.