Published online by Cambridge University Press: 06 April 2009
Seven daily injections of betamethasone given early in the infection adversely affect the immune response of rats and mice to Babesia microti and B. rodhaini. Betamethasone given late in the infection, when the parasitaemias are declining, causes recrudescences. The effects of betamethasone are reversible and those animals which survive the primary parasitaemia recover even if further courses of drug treatment are given. Betamethasone causes recrudescences of parasitaemia in some voles and field mice harbouring subpatent infections. Attention is drawn to the possibility that the therapeutic use of corticosteroids may enhance piroplasm infections and that elevated corticosteroid levels, resulting from stress situations, may affect latent piroplasmosis in wild caught rodents.