Vector and Water-Borne Pathogens Research Group, School of Veterinary and Life Sciences, Murdoch University, Perth, Western Australia, Australia.
Vector and Water-Borne Pathogens Research Group, School of Veterinary and Life Sciences, Murdoch University, Perth, Western Australia, Australia.
Ticks Tick Borne Dis. 2018 Mar;9(3):632-637. doi: 10.1016/j.ttbdis.2018.02.001. Epub 2018 Feb 8.
Piroplasms, including the genera Babesia and Theileria, are intra-erythrocytic protozoa that are generally transmitted by ticks and are the aetiological agents for piroplasmosis in animals, as well as humans, worldwide. In Australia, numerous studies have been conducted on piroplasms in domestic animals; however, less is known about these protozoa in ticks from native wildlife. The present study characterised piroplasms in Ixodes australiensis (n = 119) and Amblyomma triguttatum (n = 35) ticks collected from kangaroos in Western Australia (WA). Approximately 7.6% (9/119) (95% CI 2.8-12.2) of the I. australiensis ticks were positive for piroplasms using nested-PCR at the 18S rRNA locus, whereas no piroplasm 18S rDNA was detected in the A. triguttatum ticks. All sequences from I. australiensis ticks were identical. Using a 852 bp multiple nucleotide alignment at the 18S rRNA variable region, sequences shared 97.6%, 94.3%, 93.5% and 93.4% pairwise identity with Theileria fuliginosa, Theileria brachyuri, Theileria penicillata, and a Theileria sp. (K1), derived from a burrowing bettong or boodie (Bettongia lesueur), respectively. Phylogenetic analysis revealed that the Theileria sp. from I. australiensis clustered together in the marsupial-associated Theileria group, with T. fuliginosa as closest sister species. Hence, we conclude that this is the first observation of T. fuliginosa-like species in I. australiensis ticks parasitising kangaroos in WA.
梨形虫，包括巴贝斯虫属和泰勒虫属，是寄生于红细胞内的原生动物，通常通过蜱传播，是全世界动物以及人类梨形虫病的病原体。在澳大利亚，已经对家畜中的梨形虫进行了大量研究；然而，对于来自本地野生动物的蜱中的这些原生动物知之甚少。本研究对从西澳大利亚州（WA）袋鼠中采集的澳大利亚扇头蜱（n=119）和三形革蜱（n=35）中的梨形虫进行了特征描述。使用巢式 PCR 在 18S rRNA 基因座检测到大约 7.6%（9/119）（95%CI 2.8-12.2）的澳大利亚扇头蜱呈梨形虫阳性，而三形革蜱中未检测到梨形虫 18S rDNA。澳大利亚扇头蜱的所有序列完全相同。使用 18S rRNA 可变区的 852bp 多核苷酸比对，序列与泰勒虫属、巴贝斯虫属、泰勒虫属和一种泰勒虫属（K1）分别共享 97.6%、94.3%、93.5%和 93.4%的成对同一性，这些序列分别来自挖掘袋狸或邦迪（Bettongia lesueur）。系统发育分析表明，澳大利亚扇头蜱中的泰勒虫属与袋形动物相关的泰勒虫属聚为一簇，与亲缘关系最近的物种是泰勒虫属黑热病相似种。因此，我们得出结论，这是首次在 WA 寄生袋鼠的澳大利亚扇头蜱中观察到泰勒虫属黑热病相似种。
