Division of Collaboration and Education, Research Center for Zoonosis Control, Hokkaido University, Kita-20, Nishi-10, Kita-ku, Sapporo, 001-0020 Hokkaido, Japan.
Laboratory of Parasitology, Veterinary Medicine Faculty, Hokkaido University, Kita-18, Nishi-9, Kita-ku, Sapporo, 060-0818 Hokkaido, Japan.
Parasite. 2020;27:46. doi: 10.1051/parasite/2020043. Epub 2020 Jul 20.
This study aimed to identify trypanosomes infecting cattle in Malawi in order to understand the importance of cattle in the transmission dynamics of Human African Trypanosomiasis (HAT) and Animal African Trypanosomosis (AAT). A total of 446 DNA samples from cattle blood from three regions of Malawi were screened for African trypanosomes by ITS1 PCR. The obtained amplicons were sequenced using a portable next-generation sequencer, MinION, for validation. Comparison of the results from ITS1 PCR and MinION sequencing showed that combining the two methods provided more accurate species identification than ITS1 PCR alone. Further PCR screening targeting the serum resistance-associated (SRA) gene was conducted to detect Trypanosoma brucei rhodesiense. Trypanosoma congolense was the most prevalent Trypanosoma sp., which was found in Nkhotakota (10.8%; 20 of 185), followed by Kasungu (2.5%; 5 of 199). Of note, the prevalence of T. b. rhodesiense detected by SRA PCR was high in Kasungu and Nkhotakota showing 9.5% (19 of 199) and 2.7% (5 of 185), respectively. We report the presence of animal African trypanosomes and T. b. rhodesiense from cattle at the human-livestock-wildlife interface for the first time in Malawi. Our results confirmed that animal trypanosomes are important causes of anemia in cattle and that cattle are potential reservoirs for human African trypanosomiasis in Malawi.
本研究旨在鉴定感染马拉维牛的锥虫，以了解牛在人类非洲锥虫病（HAT）和动物非洲锥虫病（AAT）传播动力学中的重要性。从马拉维三个地区的牛血液中采集了 446 份 DNA 样本，通过 ITS1 PCR 筛查非洲锥虫。使用便携式下一代测序仪 MinION 对获得的扩增子进行测序，以进行验证。ITS1 PCR 和 MinION 测序结果的比较表明，与单独使用 ITS1 PCR 相比，两种方法的结合提供了更准确的物种鉴定。进一步针对血清抗性相关（SRA）基因进行 PCR 筛选，以检测布氏锥虫罗得西亚亚种。锥虫刚果种是最常见的锥虫种，在恩科塔科塔（10.8%；185 例中的 20 例）和卡松古（2.5%；199 例中的 5 例）均有发现。值得注意的是，通过 SRA PCR 检测到的 T. b. rhodesiense 在卡松古和恩科塔科塔的流行率较高，分别为 9.5%（199 例中的 19 例）和 2.7%（185 例中的 5 例）。我们首次在马拉维报告了在人畜野生动物接触界面从牛中存在动物非洲锥虫和 T. b. rhodesiense。我们的结果证实，动物锥虫是牛贫血的重要原因，并且牛是马拉维人类非洲锥虫病的潜在传染源。
