Molecular identification of bloodmeal sources and trypanosomes in Glossina spp., Tabanus spp. and Stomoxys spp. trapped from cattle farm settlements in southwest Nigeria.

The interaction of host, vector and parasite in bovine trypanosomiasis transmission cycles in southwest Nigeria is not yet well understood. Trypanosoma species infection prevalence and bloodmeal sources were determined for the transmitting vectors (Glossina, Tabanus and stomoxyine) collected from cattle settlements using Nzi traps in southwest Nigeria. Sequenced cyt B mitochondrial DNA segments obtained from vector digestive tracts identified bloodmeal sources from eight host species namely human, cattle, hippopotamus, giraffe, gazelle, spotted hyena, long-tailed rat and one unidentified host. Overall 71.1% (95%CI: 63.0-78.1), 33.3% (95%CI: 21.9-47.0) and 22.2% (95%CI: 16.2-29.9) of Glossina, Tabanus and stomoxyine were positive for trypanosomes respectively. The observed trypanosome species were T. vivax, T. congolense, T. brucei, T. evansi, T. simae and T. godfreyi. Trypanosome DNA was more prevalent in tsetse (34.8% T. vivax, 51.1% T. b. brucei, 5.2% T. congolense, 4.4% T. simiae and 24.4% mixed infections) than other flies and the main determinants in all the flies were seasonal factors and host availability. To the best of our knowledge, this is the first report of Trypanosoma species in Tabanus and stomoxyine in Nigeria. Therefore, vector control programmes should always consider biting flies along with tsetse flies in the control of human and animal trypanosomiasis.
Keywords: Glossina, Tabanus, stomoxyine, cattle, trypanosomes, blood-meal, southwest Nigeria