Effect of aflatoxin B-1 on transmissibility,course of infection and chemotherapy of Trypanosoma congolese in Mice

Abstract

Nlycotoxins are secondary metabolites produced by many fungi known to be common contaminants of both human food and animal feed. If ingested in minute but regular doses, they are known to cause suppression of the immune system and therefore, alter pathogenesis of many infectious diseases. Trypanosoma congolense an intravascular parasite is the most important cause of African animal trypanosomoses. The objective of this work was to investigate the effect of aflatoxin B-l(AFB-1) a common mycotoxin on transmissibility and course of infection of T. congolense. Female Swiss white mice were intra-peritoneally injected with O.5mg/kg body weight of aflatoxin B-l upto l0 times and on the 21“ day post commencement of injection of AFB-1 were infected with T. congolense. Parasitological parameters including clinical signs, weight, packed cell volume and parasitaemia levels of aflatoxin B-1-injected-T. c0ng0lense- infected mice were compared with those of T. congolense-infected mice. In a separate study, aflatoxin B-1-injected-T. congolense-infected and T. congolense-infected mice were fed on by 400 tsetse flies. Some of these flies were dissected to observe establishment of infection in their midgut and proboscis. The remaining tsetse flies were used to cyclically infect 100 mice. Analysis of variance (ANOVA) and mean separation methods were used to determine differences between the test and control mice while Kaplan Meier method was used to analyze and compare the survival between the two groups of mice. It was observed that there was no significant difference in pre-patent periods, packed cell volume and parasitemia levels of the mice. Mean body weight was significantly different (p<0.05) and clinical signs were more pronounced in aflatoxin B-l-injected-T. congolense-infected mice than T. cangolense-infected mice. Two out of the 12 treated mice relapsed on day 20 post treatment and survived for upto 45 days later. Establishment of infection within the tsetse flies and subsequent transmission to uninfected mice was also not significant. It was concluded that aflatoxin B-1 has an effect on the pathogenesis, and not on transmissibility and response of T. congolense to chemotherapy.