Infection of mice concurrently with Schistosoma mansoni and rodent malarias: contrasting effects of patent S. mansoni infections on Plasmodium chabaudi, P. yoelii and P. berghei

Abstract

Blood cell parasitaemias of Plasmodium chabaudi, P. yoelii and P. berghei were examined in mice infected with Schistosoma mansoni and in controls with no schistosome infection. Plasmodium chabaudi parasitaemias were suppressed relative to control values in mice with patent (eight week or older bisexual) infections of S. mansoni, but were not affected by either prepatent bisexual or adult unisexual (male worm alone) schistosome infections. The growth of one strain of P. yoelii was enhanced in mice with patent S. mansoni infection and unaffected by prepatent schistosome infections. Concurrent S. mansoni infections did not have any apparent effect on P. berghei blood parasitaemias. The contrast between P. chabaudi and P.yoelii may be explained in terms of patent S. mansoni infections inducing a reticulocytosis and the predelictions of P. yoelii for invading reticulocytes and P. chabaudi for more mature erythrocytes.