Neospora caninum is considered one of the main causes of abortion in cattle but can also cause abortion in sheep. There is limited knowledge of the N. caninum population infecting sheep, and only one N. caninum isolate from a pregnant sheep from Japan has been reported. This study describes the in vitro isolation and genetic characterization of two new sheep isolates of N. caninum implicated in ovine reproductive failure. We used IFN-γ-knockout mice inoculated with PCR-positive brain homogenates from two clinically healthy but congenitally infected lambs at 4.5 months of age for parasite isolation. The lambs were born to dams from a sheep farm that had experienced pregnancy failure caused by N. caninum in successive generations. Tachyzoites were microscopically visualized in peritoneal flushes from all inoculated mice and were also observed in MARC-145 cell cultures within one week after inoculation with peritoneal flushes. Two N. caninum isolates, Nc-Spain11 and Nc-Spain12, were obtained from each lamb. The genotyping of the Nc-Spain11 and Nc-Spain12 isolates based on 9 microsatellite markers showed identical multilocus genotype (MLG). Comparison between a previous N. caninum genotype dataset including 80 MLGs from Argentinean, Spanish, Mexican, German and Scottish bovine isolates and the Japanese sheep isolate showed that the Nc-Spain11 and Nc-Spain12 MLG was unique and differed from the other MLGs. eBURST analyses showed that the Nc-Spain11 and Nc-Spain12 MLG was genetically clustered with other bovine MLGs and one ovine MLG, and the nearest genetic relationship was with an MLG from a bovine abortion collected in the same geographical area of Galicia.

中文翻译：

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从自然感染绵羊的犬新孢子虫的分离和遗传特性。

犬新孢子虫被认为是牛流产的主要原因之一，但也可能导致绵羊流产。关于犬新孢子虫感染绵羊的知识知之甚少，并且据报道只有一只来自日本怀孕绵羊的犬新孢子虫分离株。这项研究描述了与绵羊生殖衰竭有关的两种新的犬新孢子虫绵羊分离株的体外分离和遗传特征。我们使用从两个临床健康但先天感染的羔羊在4.5个月大时接种了PCR阳性脑匀浆的IFN-γ敲除小鼠进行寄生虫分离。羔羊是由绵羊农场的水坝出生的，该绵羊农场连续几代经历了犬新孢子虫引起的妊娠失败。速殖子在所有接种的小鼠的腹膜冲洗液中都可以在显微镜下观察到，并且在腹膜冲洗液接种后一周内在MARC-145细胞培养物中也可以观察到。从每只羔羊中获得了两个犬新孢子虫分离株Nc-Spain11和Nc-Spain12。基于9个微卫星标记的Nc-Spain11和Nc-Spain12分离株的基因分型显示相同的多位点基因型（MLG）。比较先前的犬新孢子虫基因型数据集，其中包括来自阿根廷，西班牙，墨西哥，德国和苏格兰的牛分离株的80个MLG，以及日本绵羊分离株，表明Nc-Spain11和Nc-Spain12 MLG是独特的，与其他MLG有所不同。eBURST分析显示，Nc-Spain11和Nc-Spain12 MLG与其他牛MLG和一个绵羊MLG在基因上成簇，