[Rats and bilharziasis in Guadeloupe].

The rats in Guadeloupe (Rattus rattus and Rattus norvegicus) may play a part in schistosomiasis in three ways: - by harbouring fertile S. mansoni, a fact which serves to increase the total population of the parasite and may eventually take part in the infestation of man; - by harbouring a great number of Ribeiroia marini, a trematode whose larval stages sterilize Biomphalaria glabrata, the vector of schistosomiasis; - simply by eating B. glabrata. The quantitative influence of these contradictory roles played by the rats upon schistosomiasis in Guadeloupe has yet to be studied.