Enhanced resistance to Plasmodium berghei in mice previously infected with Trichinella spiralis.

Infection with Trichinella spiralis larvae greatly enhanced the resistance of adult mice against fatal infection with Plasmodium berghei given 10 and 30 days after T. spiralis infection. Mice infected with T. spiralis had a markedly activated mononuclear phagocytic system and significantly low reticulocyte levels at the time the mice were challenged with P. berghei. Therefore, the partially subdued parasitaemia and prolonged survival of Trichinella-Plasmodium-infected mice may be attributed, in part, to macrophage activity and reticulocytopenia exerting a specific anti-P. berghei effect. This study suggests the role of T. spiralis induced reticulocytopenia and activated macrophages as potential mechanisms in resistance to P. berghei infection.