Soomro Samiullah, Tuangpermsub Siwaporn, Ngamprasertwong Thongchai, Kaewthamasorn Morakot
The International Graduate Program of Veterinary Science and Technology (VST), Faculty of Veterinary Science, Chulalongkorn University, Bangkok, 10330, Thailand.
Center of Excellence in Veterinary Parasitology, Department of Pathology, Faculty of Veterinary Science, Chulalongkorn University, Bangkok, 10330, Thailand.
Parasit Vectors. 2025 Jul 26;18(1):298. doi: 10.1186/s13071-025-06934-5.
Bats are known reservoirs for various pathogens, many of which can infect other animals through blood-feeding arthropods. Over 100 bat species have been identified as hosts for kinetoplastid protozoans, including ≥ 30 distinct Trypanosoma spp. However, bat trypanosomes remain relatively understudied owing to the nocturnal behavior of their hosts and legal restrictions on their capture for research. In Southeast Asia, particularly Thailand, only one study has investigated bat trypanosomes, leaving their distribution and transmission pathways largely unexplored.
Between April 2021 and November 2023, bats were captured at ten locations across four provinces in Thailand. Blood samples were collected, examined microscopically, and screened for Trypanosoma DNA targeting the SSU rRNA and gGAPDH genes. Phlebotomine sand flies from bat sampling sites were collected and analyzed for Trypanosoma DNA and blood meal sources. Sequences were identified using BLASTn searches, while genetic relationships were assessed through pairwise genetic distance, phylogenetic reconstruction, and TCS haplotype network analyses. In addition, species delimitation was conducted to validate unidentified sequences at the species level.
Out of 368 bats, 40 (10.9%) tested positive for four Trypanosoma species (including two previously named: T. dionisii and T. noyesi). Out of 189 sand flies, a single one tested positive for an unnamed anuran trypanosome from a gravid female (Phlebotomus stantoni), and the study was unable to detect the blood source of this sand fly. In total, 37 pools (189 specimens) of female sand flies-comprising 159 unfed, 29 gravid, and 1 engorged specimen-were analyzed for vertebrate blood meals, but none tested positive. Multiple analyses (BLASTn, phylogenetics, haplotype networks, pairwise genetic distances, and species delimitation) also confirmed a Trypanosoma sp. in a gravid sand fly, along with T. dionisii and T. noyesi, plus two uncharacterized bat-associated species.
The Trypanosoma spp. detected in the present study aligns with prior reports of diverse trypanosomes in bat populations, reinforcing their role as key reservoirs. Notably, a single sand fly (Phlebotomus stantoni) tested positive for an unnamed anuran trypanosome, but its blood meal source could not be determined, leaving unresolved questions about potential transmission pathways.
蝙蝠是多种病原体的已知宿主，其中许多病原体可通过吸血节肢动物感染其他动物。已确定100多种蝙蝠为动质体原生动物的宿主，包括≥30种不同的锥虫属物种。然而，由于宿主的夜行性以及对捕获蝙蝠进行研究的法律限制，蝙蝠锥虫仍相对未得到充分研究。在东南亚，特别是泰国，只有一项研究调查过蝙蝠锥虫，其分布和传播途径在很大程度上仍未得到探索。
在2021年4月至2023年11月期间，在泰国四个省份的十个地点捕获蝙蝠。采集血样，进行显微镜检查，并针对小亚基核糖体RNA（SSU rRNA）和糖酵解甘油醛-3-磷酸脱氢酶（gGAPDH）基因筛选锥虫DNA。收集蝙蝠采样地点的白蛉，分析其锥虫DNA和血餐来源。使用BLASTn搜索鉴定序列，同时通过成对遗传距离、系统发育重建和TCS单倍型网络分析评估遗传关系。此外，进行物种界定以在物种水平验证未鉴定的序列。
在368只蝙蝠中，40只（10.9%）对四种锥虫物种检测呈阳性（包括两种先前命名的：狄氏锥虫和诺氏锥虫）。在189只白蛉中，有一只来自怀孕雌性白蛉（斯坦顿白蛉）的未命名无尾两栖类锥虫检测呈阳性，该研究未能检测到这只白蛉的血源。总共分析了37组（189个样本）雌性白蛉——包括159只未进食的、29只怀孕的和1只饱血样本——的脊椎动物血餐，但均未检测呈阳性。多项分析（BLASTn、系统发育学、单倍型网络、成对遗传距离和物种界定）还证实了一只怀孕白蛉体内存在一种锥虫，以及狄氏锥虫和诺氏锥虫，另外还有两种未鉴定的与蝙蝠相关的物种。
本研究中检测到的锥虫物种与先前关于蝙蝠种群中多种锥虫的报告一致，强化了它们作为主要宿主的作用。值得注意的是，一只白蛉（斯坦顿白蛉）对一种未命名的无尾两栖类锥虫检测呈阳性，但其血餐来源无法确定，这使得关于潜在传播途径的问题仍未得到解决。
