Infectivity in rodents of Schistosoma mansoni cercariae of human and murine origin.

Experimental infections of white laboratory mice and wild rats (Rattus rattus) with cercariae of Schistosoma mansoni of different descent, whether murine or human, demonstrate that there is no significant difference in the probability of maturation of these cercariae into adult schistosomes. These results enable us to hypothesize that the reverse would be true, i.e. that cercariae of murine or human descent would be capable of infecting man with the same success rate. Circulation of the parasite from man to the rat and from the rat to man may therefore occur in natural habitats, which does not mean that rodents can maintain indefinitely and independently Schistosoma mansoni, nor does it mean that murine strains may not evolve locally.