Division of Health Sciences, Murdoch University, Murdoch, Western Australia 6150, Australia.
Vet Parasitol. 2011 Dec 29;183(1-2):21-30. doi: 10.1016/j.vetpar.2011.07.009. Epub 2011 Jul 12.
In the present study, the occurrence and molecular phylogeny of trypanosome parasites were studied in both wild and captive marsupials from Western Australia and Queensland. Blood samples were screened by PCR at the 18S rDNA locus, and the glycosomal glyceraldehyde phosphate dehydrogenase gene. Overall, 5.3% of the blood samples were positive at the 18S rDNA locus. All positives belonged to wild-captured Western Australian individuals, where trypanosome-specific DNA was detected in 9.8% of the screened samples from wild marsupials, in common brushtail possums, and woylies. The detection rate of trypanosome DNA in these two host species was 12.5% and 20%, respectively. Phylogenetic analyses based on two loci, indicated that the possum-derived trypanosome isolates were genetically distinct, and most closely related to the Australian marsupial trypanosomes H25 from a kangaroo, and BRA2 from a bush rat. This is the first study to genetically characterise trypanosome isolates from possums. The analysis of the woylie-derived isolates demonstrated that this marsupial host can harbour multiple genotypes within the same geographical location and furthermore multiple genotypes within the same host, indicative of mixed infections. All the woylie-derived genotypes grouped with trypanosomes found in Australian marsupials, suggesting that they are more likely to belong to an endemic or Australasian trypanosome species. This is the first study to genetically characterise trypanosome isolates from possums (Trichosurus vulpecula). Although the clinical significance of these infections is currently unknown, the identification of these novel sequences may support future investigations on transmission, threats to endangered wildlife, and evolutionary history of the genus Trypanosoma.
在本研究中，对来自西澳大利亚州和昆士兰州的野生和圈养有袋动物中的锥体虫寄生虫的发生和分子系统发育进行了研究。通过 PCR 在 18S rDNA 基因座和糖基化醛缩酶磷酸甘油基因对血液样本进行了筛选。总体而言，18S rDNA 基因座的 5.3%的血液样本呈阳性。所有阳性结果均来自西澳大利亚州的野生捕获个体，在从野生有袋动物、普通帚尾袋貂和沃利中筛选的样本中，检测到锥体虫特异性 DNA 的比例分别为 9.8%、9.8%和 9.8%。这两种宿主物种中锥体虫 DNA 的检出率分别为 12.5%和 20%。基于两个基因座的系统发育分析表明，袋貂来源的锥体虫分离株在遗传上是不同的，与来自袋鼠的澳大利亚有袋动物锥体虫 H25 和来自 bush rat 的 BRA2 最为密切相关。这是首次对来自帚尾袋貂的锥体虫分离株进行遗传特征分析。对沃利来源的分离株的分析表明，这种有袋动物宿主可以在同一地理位置内携带多种基因型，并且在同一宿主内也可以携带多种基因型，表明存在混合感染。所有沃利来源的基因型均与在澳大利亚有袋动物中发现的锥体虫聚在一起，这表明它们更有可能属于地方性或澳大拉西亚锥体虫物种。这是首次对来自帚尾袋貂（Trichosurus vulpecula）的锥体虫分离株进行遗传特征分析。尽管这些感染的临床意义目前尚不清楚，但这些新序列的鉴定可能支持未来对传播、濒危野生动物面临的威胁以及锥体虫属的进化历史的研究。
