Odeniran P O, Macleod E T, Ademola I O, Welburn S C
Department of Veterinary Parasitology and Entomology, Faculty of Veterinary Medicine, University of Ibadan, Ibadan, Nigeria.
Division of Infection and Pathway Medicine, University of Edinburgh, Edinburgh, U.K.
Med Vet Entomol. 2019 Jun;33(2):269-281. doi: 10.1111/mve.12358. Epub 2019 Feb 7.
The interactions of host, vector and parasite in bovine trypanosomiasis transmission cycles in southwest Nigeria are not yet well understood. Trypanosoma (Trypanosomatida: Trypanosomatidae) species infection prevalences and bloodmeal sources were determined in transmitting vectors of the genera Glossina (Diptera: Glossinidae), Tabanus (Diptera: Tabanidae) and Stomoxys (Diptera: Muscidae) collected using Nzi traps in cattle settlements in southwest Nigeria. Sequenced cytochrome 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 species. Overall, 71.1% [95% confidence interval (CI) 63.0-78.1], 33.3% (95% CI 21.9-47.0) and 22.2% (95% CI 16.2-29.9), respectively, of Glossina, Tabanus and Stomoxys flies were positive for trypanosomes. The observed trypanosome species were Trypanosoma vivax, Trypanosoma congolense, Trypanosoma brucei, Trypanosoma evansi, Trypanosoma simiae and Trypanosoma godfreyi. Trypanosome DNA was more prevalent in tsetse (34.8% Tr. vivax, 51.1% Tr. b. brucei, 5.2% Tr. congolense, 4.4% Tr. simiae and 24.4% mixed infections) than in other flies and the main determinants in all flies were seasonal factors and host availability. To the best of the present group's knowledge, this is the first report of Trypanosoma species in Tabanus and Stomoxys flies in Nigeria. It indicates that vector control programmes should always consider biting flies along with tsetse flies in the control of human and animal trypanosomiasis.
在尼日利亚西南部牛锥虫病传播周期中，宿主、媒介和寄生虫之间的相互作用尚未得到充分了解。在尼日利亚西南部的牛群聚居地，使用恩齐诱捕器收集了舌蝇属（双翅目：舌蝇科）、虻属（双翅目：虻科）和厩螫蝇属（双翅目：蝇科）的传播媒介，测定了锥虫属（动基体目：锥虫科）物种感染率和血餐来源。从媒介消化道获得的细胞色素B线粒体DNA片段测序确定了八种宿主物种的血餐来源，即人类、牛、河马、长颈鹿、瞪羚、斑鬣狗、长尾大鼠和一个未鉴定物种。总体而言，舌蝇、虻和厩螫蝇中锥虫阳性率分别为71.1%[95%置信区间（CI）63.0 - 78.1]、33.3%（95%CI 21.9 - 47.0）和22.2%（95%CI 16.2 - 29.9）。观察到的锥虫物种有活泼锥虫、刚果锥虫、布氏锥虫、伊氏锥虫、西氏锥虫和戈氏锥虫。锥虫DNA在采采蝇中比在其他蝇类中更普遍（34.8%活泼锥虫、51.1%布氏锥虫、5.2%刚果锥虫、4.4%西氏锥虫和24.4%混合感染），所有蝇类中的主要决定因素是季节因素和宿主可得性。就本研究团队所知，这是尼日利亚虻和厩螫蝇中锥虫物种的首次报告。这表明在控制人类和动物锥虫病时，媒介控制计划应始终将刺叮蝇和采采蝇一并考虑在内。
