Comparison of the effect of T-2 toxin with that of dexamethasone or cyclophosphamide on resistance to Babesia microti infection in mice.

The effect of T-2 toxin on host resistance to acute and latent Babesia microti infections was evaluated in mice and was compared with the effects of the immunosuppressive drugs dexamethasone and cyclophosphamide. Mice with acute or latent B microti infection were treated with 2 mg of T-2 toxin/kg of body weight, 0.2 mg of dexamethasone/kg, or 30 mg of cyclophosphamide/kg daily for 5 days. Treatment with dexamethasone or cyclophosphamide caused significant (P less than 0.05) increases in Babesia parasitemia during acute infection and significantly (P less than 0.05) prolonged the duration of parasitemia during acute babesiosis. Treatment with T-2 toxin caused a transient significant (P less than 0.05) increase in Babesia parasitemia on day 10 after acute infection and numerical, though statistically nonsignificant, increases in the maximal level and duration of parasitemia during acute babesiosis. Significant (P less than 0.005) recrudescence of parasitemia was observed in the dexamethasone- and cyclophosphamide-treated mice with latent Babesia infection. Treatment with T-2 toxin did not cause recrudescence of parasitemia in mice with latent Babesia infection.