RESUMEN
In this study, the results obtained in a control programme of schistosomiasis in Ravena (Sabará, Minas Gerais) between 1980 and 1992 are evaluated. Control measures used in this programme were: specific treatment of the people infected with Schistosoma mansoni at four year-intervals (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 < or = 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 < or = 0.05) was observed. No cases of the severe form of the disease were diagnosed in the area. Factors independently associated with the infection were in 1980 daily sand extraction and the lack of tap water in residences and in 1992 daily sand extraction and fishing and weekly swimming. Concluding, the supply of tap water together with quadrennial treatments significantly diminished both the prevalence and intensity of the S. mansoni infection, with the additional gain of persistent low indices even after four-year intervals between the treatments.
Asunto(s)
Esquistosomiasis mansoni/prevención & control , Abastecimiento de Agua , Brasil/epidemiología , Humanos , Prevalencia , Esquistosomiasis mansoni/tratamiento farmacológico , Esquistosomiasis mansoni/epidemiologíaRESUMEN
1. The reproduction of the snail Biomphalaria glabrata, one of the intermediate hosts of Schistosoma mansoni, was evaluated under laboratory conditions by measuring egg production, number of ovipositions, number of eggs per oviposition, and hatching rate using a Latin square design with five different temperature treatments. This permitted the elimination of occasional variation in oviposition due to manipulation or a priori group. 2. Egg production and spawning rates were higher at temperatures between 20.0 and 27.5 degrees C than at 17.5 degrees C. Number of eggs per spawning and hatching rate did not vary with temperature. 3. During a 3-day adaptation phase, a short-term thermal effect appeared in which some indices of reproductive rates differed significantly from those of the experimental phase.
Asunto(s)
Biomphalaria/anatomía & histología , Oviposición , Temperatura , Adaptación Fisiológica , Animales , Biomphalaria/fisiología , Femenino , ReproducciónRESUMEN
1. The reproduction of the snail Biomphalaria glabrata, one of the intermediate hosts of Schistosoma mansoni, was evaluated under laboratory conditions by measuring egg production, number of ovipositions, number of eggs per oviposition, and hatching rate using a Latin square design with five different temperature treatments. This permitted the elimnation of occasional variation in oviposition due to manipulation or a priori group. 2. Egg production and spawning rates were higher at temperatures between 20.0 and 27.5-C than at 17.5-C. Number of eggs per spawning and hatching rate did not vary with temperature. 3. During a 3-day adaptation phase, a short-term therminal effect appeared in chich some indices of reproductive rates differed signifcantly from those of the experimental phase