This study was conducted to determine the prevalence of trypanosomes, infective to cattle and humans in tsetse flies caught in Simanjiro district, which borders with Tarangire National park in northern Tanzania. A total of 1000 tsetse flies were caught during the semi dry season in July and August 2014 using F 3 and Epsilon traps. Results revealed Glossina swynertonni as the most abundant species (72%) followed by Glossina morsitans morsitans (21%) and Glossina pallidipes (7%) in the study area. Whole fly DNA was extracted from all the 1000 flies caught in the study area.

Analysis of fly DNA for detection of trypanosome species showed a 3% (30/1000) overall infection rate of which 13.3% (4/30) flies were co-infected with Trypanosoma brucei and Trypanosoma vivax, while 3.3% (1/30) were co-infected with Trypanosoma congolense and Tripanosoma vivax. Majority of flies (83.3%, 25/30) were infected with T. vivax. All three trypanosome species were detected in G.swynertonni flies but G.m. morsitans carried T. vivax and T. brucei. No parasites were detected in G. pallidipes flies. Further, no human infective trypanosomes were detected when T. brucei positive flies were analysed with specific primers for SRA-PCR. The study confirms presence of cattle infective trypanosomes and absence of human-infective trypanosomes in tsetse flies caught in the study area.