A COMPARISON OF INFECTIONS IN MICE WITH THREE SPECIES OF SCHISTOSOMES, SCHISTOSOMA MANSONI, SCHISTOSOMA JAPONICUM AND SCHISTOSOMATIUM DOUTHITTI1

Abstract

The early phases of infection in mice with Schistosoma japonicum, Schistosomatium douthitti, and Schistosoma mansoni were studied in some detail under closely similar conditions. All 3 species produced lung hemorrhages while migrating to the portal system, but S. japonicum and S. douthitti produced many conspicuous hemorrhages soon after exposure and these cleared rapidly, while S. mansoni produced relatively small numbers of hemorrhages over a comparatively long period of time. It is concluded that the first two species characteristically produce lung hemorrhage in the mouse when they migrate, but that S. mansoni does not always do so. Few S. japonicum and S. douthitti were found in the lungs during the period in which they were migrating to the portal system while many S. mansoni were consistently recovered from the lungs between the fourth and fourteenth days following exposure. Apparently the latter pass through the lungs slowly. The S. japonicum and S. douthitti reached the portal system quickly after a rapid passage through the lungs, but S. mansoni reached the portal system much later and accumulated there comparatively slowly. A great proportion of the S. japonicum and S. douthitti reached the portal system but only a relatively small proportion of the S. mansoni applied to the skin did so.