Vector and Waterborne Pathogens Research Group, School of Veterinary and Life Sciences, Murdoch University, Perth, Western Australia, Australia.
Western Australian State Agricultural Biotechnology Centre, Murdoch University, Perth, Western Australia, Australia.
Parasit Vectors. 2018 Mar 20;11(1):197. doi: 10.1186/s13071-018-2775-y.
Apicomplexan tick-borne pathogens that cause disease in companion animals include species of Babesia Starcovici, 1893, Cytauxzoon Neitz & Thomas, 1948, Hepatozoon Miller, 1908 and Theileria Bettencourt, Franca & Borges, 1907. The only apicomplexan tick-borne disease of companion animals that is known to occur in Australia is babesiosis, caused by Babesia canis vogeli Reichenow, 1937 and Babesia gibsoni Patton, 1910. However, no molecular investigations have widely investigated members of Apicomplexa Levine, 1980 in Australian ticks that parasitise dogs, cats or horses, until this present investigation.
Ticks (n = 711) removed from dogs (n = 498), cats (n = 139) and horses (n = 74) throughout Australia were screened for piroplasms and Hepatozoon spp. using conventional PCR and Sanger sequencing. The tick-borne pathogen B. vogeli was identified in two Rhipicephalus sanguineus Latreille ticks from dogs residing in the Northern Territory and Queensland (QLD). Theileria orientalis Yakimov & Sudachenkov, 1931 genotype Ikeda was detected in three Haemaphysalis longicornis Neumann ticks from dogs in New South Wales. Unexpectedly, the exotic tick-borne pathogen Hepatozoon canis James, 1905 was identified in an Ixodes holocyclus Neumann tick from a dog in QLD. Eight novel piroplasm and Hepatozoon species were identified and described in native ticks and named as follows: Babesia lohae n. sp., Babesia mackerrasorum n. sp., Hepatozoon banethi n. sp., Hepatozoon ewingi n. sp., Theileria apogeana n. sp., Theileria palmeri n. sp., Theileria paparinii n. sp. and Theileria worthingtonorum n. sp. Additionally, a novel cf. Sarcocystidae sp. sequence was obtained from Ixodes tasmani Neumann but could not be confidently identified at the genus level.
Novel species of parasites in ticks represent an unknown threat to the health of companion animals that are bitten by these native tick species. The vector potential of Australian ticks for the newly discovered apicomplexans needs to be assessed, and further clinical and molecular investigations of these parasites, particularly in blood samples from dogs, cats and horses, is required to determine their potential for pathogenicity.
引起伴侣动物疾病的锥虫蜱传病原体包括星突巴贝斯虫（Babesia Starcovici，1893）、细胞锥虫（Cytauxzoon Neitz & Thomas，1948）、肝孢子虫（Hepatozoon Miller，1908）和泰勒虫（Theileria Bettencourt、Franca & Borges，1907）。已知在澳大利亚发生的唯一一种伴侣动物锥虫蜱传疾病是犬巴贝斯虫病，由巴贝斯虫（Babesia canis vogeli Reichenow，1937）和巴贝斯虫（Babesia gibsoni Patton，1910）引起。然而，直到本研究之前，尚未对寄生在澳大利亚犬、猫或马身上的蜱类中的锥虫属（Apicomplexa Levine，1980）成员进行广泛的分子调查。
从澳大利亚各地的犬（n=498）、猫（n=139）和马（n=74）身上采集的蜱（n=711），使用常规 PCR 和 Sanger 测序，对梨形虫和肝孢子虫属进行了筛查。在北领地和昆士兰州（QLD）的两只犬身上发现了来自犬的拉氏血蜱（Rhipicephalus sanguineus Latreille）中的巴贝斯虫（B. vogeli）。在新南威尔士州的三只犬身上的长角血蜱（Haemaphysalis longicornis Neumann）中检测到东方泰勒虫（Theileria orientalis Yakimov & Sudachenkov，1931）基因型 Ikeda。出人意料的是，在昆士兰州的一只犬身上的硬蜱（Ixodes holocyclus Neumann）中发现了外来的肝孢子虫（Hepatozoon canis James，1905）。在本地蜱中鉴定并描述了 8 种新的梨形虫和肝孢子虫，并分别命名为：巴贝斯虫（Babesia lohae n. sp.）、巴贝斯虫（Babesia mackerrasorum n. sp.）、肝孢子虫（Hepatozoon banethi n. sp.）、肝孢子虫（Hepatozoon ewingi n. sp.）、泰勒虫（Theileria apogeana n. sp.）、泰勒虫（Theileria palmeri n. sp.）、泰勒虫（Theileria paparinii n. sp.）和泰勒虫（Theileria worthingtonorum n. sp.）。此外，从塔斯马尼亚硬蜱（Ixodes tasmani Neumann）中获得了一种新的疑似肉孢子虫科序列，但无法在属级水平上进行明确鉴定。
在蜱类中发现的新寄生虫种代表了对被这些本地蜱类叮咬的伴侣动物健康的未知威胁。需要评估澳大利亚蜱类的载体潜力，并且需要对这些新发现的锥虫类进行进一步的临床和分子研究，特别是在来自犬、猫和马的血液样本中，以确定它们的致病性潜力。
