A comparative account of the effects of betamethasone on mice infected with Plasmodium vinckei chabaudi and Plasmodium berghei yoelii

The malaria parasites, Plasmodium berghei yoelii and P. vinckei chabaudi, run comparable courses of infection in mice. When mice were treated with betamethasone infections with P. v. chabaudi were enhanced while those of P. b. yoelii were depressed. Antibody levels in betamethasone-treated mice infected with either P. b. yoelii or P. v. chabaudi were depressed to similar extents. The differences in parasitaemias in the two different infections are attributed to the suppression of reticulocyte production by betamethasone. P. b. yoelii preferentially invades reticulocytes and the patterns of parasitaemia follow the level of reticulocytes in the blood. P. v. chabaudi has no preference for reticulocytes and the pattern of parasitaemia is influenced by the depressed immunological response of the host.