[Complement to the epidemiologic study of the focus of Schistosoma mansoni bilharziasis in Kara (northern Togo)]

Abstract

The present study on the focus of schistosomiasis mansoni of Kara (Northern Togo) complements a report already published in the Bulletin de la Société de Pathologie Exotique in 1988 (9). The following results were obtained through different experiments carried out with snails collected in Kara. According to the season, 3 to 15% of the Biomphalaria pfeifferi studied, were infected. The maximal release of cercariae was observed between 11 am and 1 pm. The survival of cercariae and their ability to infect mice were not superior to 16 hours. Data obtained with the chaetotaxy of miracidia of the Kara strain were compatible with those obtained with african strains by other authors. Moreover, B. pfeifferi from Kara was more susceptible to the Kara strain of Schistosoma mansoni than B. pfeifferi collected in the south of Togo or than B. glabrata from the new world. On the contrary, B. pfeifferi from Kara was susceptible to a strain of S. mansoni from Brazil and was able to produce infectious cercariae. In addition, the search for an animal reservoir was carried out; 3 of the 112 (2.7%) wild rodents captured around the river Kara, were infected. This relatively low number of infected rodents was compatible with the usual findings in Africa where the animal reservoir is considered from human origin and has no importance in the transmission of S. mansoni as it could have in South America and West Indies.