Strongyloides ratti infections in congenitally hypothymic (nude) mice.

The course of infection with Strongyloides ratti was examined in congenitally hypothymic CBA/H, C57Bl/6 and BALB/c nude mice. The intensity of infection and the duration of faecal larval excretion were both increased in nude mice when compared with intact mice. Adult worms persisted in the small intestine of nude mice for at least 6 weeks. Greater worm burdens were found in such mice after subcutaneous injection as compared with percutaneous infection. Hypothymic mice did not acquire resistance to re-infection. It is concluded that both the spontaneous expulsion of worms in primary infection and resistance to challenge infection are T cell-dependent events. Autoinfection was not seen.