Effect of aflatoxin B1 on the therapeutic efficacy of suramin in Trypanosoma brucei rhodesiense-infected mice

Abstract

Through immuno-suppression, aflatoxins could affect drug and vaccine efficacy. Such effects have not been evaluated in treatment of many diseases including trypanosomiasis. We assessed the effect of aflatoxin B1 on the efficacy of suramin, the drug used for treatment of early stage sleeping sickness, in a murine model. Mice were fed daily on a diet containing 0.50 mg aflatoxin/kg body weight or a placebo. They were infected with Trypanosoma brucei rhodesiense on day 7 post-aflatoxin exposure and then treated with one of 6 different doses of suramin (4.0, 4.5, 5.0, 5.5, 6.0 and 6.5 mg/kg body weight) at the onset of parasitemia. The mice were fed on aflatoxin diet for 30 days and the curative dose values (CD_{50, 75, and 90}) computed and compared using a logistic linear regression model. Aflatoxin B1 induced transient protection of the host against T. b. rhodesiense infection and a consistent increase in suramin CD values in the mice suggesting reduced drug efficacy. Aflatoxicosis hindered curative treatment of T. b. rhodesiense infection in mice, and may contribute to reduced efficacy of suramin during treatment of sleeping sickness in man.