Department of Physiology, Anatomy and Microbiology, School of Life Sciences, La Trobe University, Bundoora, Victoria, Australia.
Department of Environment, Land, Water and Planning, Arthur Rylah Institute for Environmental Research, Heidelberg, Victoria, Australia.
Transbound Emerg Dis. 2022 Jul;69(4):1862-1871. doi: 10.1111/tbed.14170. Epub 2021 Jun 7.
Infection with Neospora caninum parasites is a leading cause of reproduction losses in cattle worldwide. In Australia, this loss is estimated to total AU$110 million every year. However, despite this considerable economic impact, the transmission cycle and the host(s) responsible for the sylvatic transmission of the parasite remain to be defined. Dingoes (Canis familiaris) have been suggested to be a wildlife host of N. caninum in Australia, but this is yet to be proven in a nonexperimental setting. This study aimed to determine the prevalence of natural N. caninum shedding in Australian wild dogs (defined as dingoes, dingo-domestic dog hybrids and feral dogs) by performing molecular analysis of faecal samples collected in wild dog populations in south-east Australia. Molecular analysis allowed host species identification and dingo purity testing, while genetic analysis of Coccidia and Neospora conserved genes allowed for parasite identification. Among the 115 samples collected and determined to belong to dingoes, dingo-domestic dog hybrids and foxes, Coccidian parasites were detected in 41 samples and N. caninum was identified in one sample of canine origin from South East Australia (Mansfield). Across all samples collected in Mansfield only 15 individuals were successfully identified by genotype. Thereby our study determined that 6.7% (1/15, 95% confidence intervals 1.2-29.9) of wild dogs were actively shedding N. caninum oocysts at this site. Further, only four individuals were identified at a second site (Swift Creek), and none were positive. This study conclusively confirms the role of wild dogs in the horizontal transmission of N. caninum parasites in Australia.
刚地弓形虫寄生虫感染是全球范围内导致牛只繁殖损失的主要原因。在澳大利亚，每年由此造成的损失估计总计达 1.1 亿澳元。然而，尽管这种经济影响相当大，但寄生虫的传播周期和负责其森林传播的宿主仍有待确定。澳大利亚的野狗（犬属的犬种）被认为是刚地弓形虫的野生动物宿主，但这尚未在非实验环境中得到证实。本研究旨在通过对澳大利亚东南部野生犬科动物（定义为野狗、野狗-家犬杂种和野犬）粪便样本进行分子分析，确定自然状态下澳大利亚野狗中刚地弓形虫的流行率。分子分析允许进行宿主物种鉴定和野狗纯度测试，而对球虫和刚地弓形虫保守基因的遗传分析则允许进行寄生虫鉴定。在收集并确定属于野狗、野狗-家犬杂种和狐狸的 115 个样本中，在 41 个样本中检测到球虫寄生虫，在来自东南澳大利亚（曼斯菲尔德）的一个犬科来源样本中鉴定出刚地弓形虫。在曼斯菲尔德收集的所有样本中，仅成功鉴定出 15 个个体的基因型。因此，我们的研究确定在该地点有 6.7%（1/15，95%置信区间为 1.2-29.9）的野狗正在积极排出刚地弓形虫卵囊。此外，在第二个地点（斯威夫特溪）仅鉴定出 4 个个体为阳性，而无一例阳性。本研究明确证实了野狗在澳大利亚刚地弓形虫寄生虫水平传播中的作用。
