Prevalence of trypanosome infection in tsetse flies from Oji River and Emene axis of Enugu State, Nigeria: A preliminary report

INTRODUCTION: Trypanosomes are protozoan parasites of vertebrates transmitted by blood-sucking tsetse fly. Trypanosomes remain a constant threat to the lives of humans and animals throughout large regions of Africa. AIMS AND OBJECTIVES: This study investigated the presence, prevalence, and species of trypanosome parasite in tsetse flies caught in two areas of no previous documented history of trypanosome infection. MATERIALS AND METHODS: For this purpose, 63 and 77 nonterenal tsetse flies were collected from Oji River and Emene areas of Enugu State Nigeria, respectively. Genomic DNA was isolated from the whole tsetse fly using genomic DNA extraction kit. Identification and characterization of trypanosome were done using two approaches: the amplification of internal transcribed spacer 1 of ribosomal DNA and the use of primers specific to Trypanozoon. RESULTS: In Oji River, of 63 tsetse flies collected, the identification of trypanosome parasite was done on 57 flies and 6 (10.71%) tsetse flies were infected with trypanosome parasite. Six flies were infected with Trypanosoma Congolense, 2 with Trypanosoma Vivax, and 1 with Trypanosoma brucei. Two mixed infections of T. vivax and T. congolense and 1 mixed infection of T. brucei and T. congolense was also identified. In Emene, of 77 tsetse flies collected, the identification of trypanosome parasite was done on 66 flies and 11 (16.6%) tsetse flies were infected with trypanosome parasite. Nine flies were infected with T. congolense, 2 with T. vivax, and 3 with T. brucei. Mixed infections identified include 2 mixed infections of T. brucei and T. congolense and 1 mixed infections of T. vivax and T. brucei. None of the subspecies of T. brucei were detected using species specific primers. DISCUSSION: This study shows the parasitological evidence on the occurrence of animal African trypanosomiasis and also demonstrated that there is likely no active transmission of human African trypanosomiasis in the study areas. CONCLUSION: This study shows that there is likely no active transmission of human African trypanosomiasis going on in these localities since no human infective form of the parasite was detected.