The course of Plasmodium berghei infection in mice latently infected with Toxoplasma gondii.

The course of infection with 2 different virulent strains of Plasmodium berghei was investigated in mice latently infected with Toxoplasma gondii. When given the highly virulent ANKA strain of P. berghei all Toxoplasma-infected mice died but the survival time was prolonged. After infection with the less virulent strain K 173 mice could survive the subsequent infection. In these cases levels of parasitemia depended upon the duration of the T. gondii infection. Mice infected for about 6 weeks with T. gondii showed maximum protection.