SCHISTOSOMA-JAPONICUM AND SCHISTOSOMA-MANSONI - COMPARISON OF LARVAL MIGRATION PATTERNS IN MICE

Mice were infected percutaneously with cercariae of Schistosoma japoni cum or S. mansoni and parasites recovered by tissue-mincing from the s kin or lungs or by perfusion of the mesenteric veins. S. japonicum had a narrow peak of recovery (up to 30%) from the lungs 3 days after inf ection, whereas lung recovery of S. mansoni peaked only on day 6 and l evelled off during the following week. Infection with S. japonicum ind uced lung petechiae, but only after most of the parasites had left the lungs. The axillary lymph nodes draining the infection site increased in weight after infection and this effect was much greater and longer with S. mansoni than with S. japonicum. S. japonicum was perfusable f rom the mesenteric veins earlier (from day 3 onwards) and in higher nu mber (40-60% from days 6 to 10) than S. mansoni (20% on day 20). The p ercentage of cercariae developing to adult worms was 57% for S. japoni cum and 33% for S. mansoni. The data demonstrate that S. japonicum mig ht escape from local tissue reactions in the skin and lungs and, due t o its rapid migration, might induce only poor lymphocyte proliferation . As a possible consequence, S. japonicum may establish more efficient ly in mice than S. mansoni.