[The "cercarial index" of Schistosoma mansoni. Epidemiological and experimental results (author's transl)].

The cercarial index defined by Bayssade-Dufour (1977) differs according to the hosts in which Schistosoma mansoni is cycled. This index is close to 1 in African human strains, 1.3 in Carribbean human strains, and 1.6 in strains kept for a number of years in rodents. The first epidemiological and experimental results supported the argument that the transmission of intestinal bilharzia in the mountainous refuge of infection at Grand-Etang, Guadeloup, is maintained exclusively by murine rodents. New epidemiological and experimental data lead us to believe that the black rat of Guadeloup is an inadequate host for S. mansoni, incapable of maintaining the parasite beyond a few cycles.