[Principal factors involved in the settlement of Biomphalaria glabrata (Say, 1818), snail intermediate host of schistosomiasis in Guadalupe (author's transl)].

Six biotopes of Biomphalaria glabrata, the snail intermediate host of schistosomiasis in Guadalupe, were investigated during one annual cycle. These six biotopes included a pond, a freshwater mangrove, a stream, a mountain lake, a "microhabitat" and a canal. These six types of biotopes were characterized by various parameters whose fluctuations reveal the main factors regulating the B. glabrata populations. The climatic factors are essential in Grande Terre and resulted in an annual development cycle well determined of all the aquatic communities. The biotic factors (Predation, competition, parasitism) are important in every type of biotope, in Grande Terre as well as in Guadalupe proper. In every type of biotope, anthropic factors are also important, but mainly in canal nets which are the principal focus of human schistosomiasis. The chemical factors themselves are less important.