Potential involvement of Neospora caninum in naturally occurring ovine abortions in New Zealand
Potential involvement of Neospora caninum in naturally occurring ovine abortions in New Zealand
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DOI：
10.1016/j.vetpar.2011.10.033
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发表时间：
2012-04-30
影响因子：
2.6
通讯作者：
Pomroy, W. E.
中科院分区：
文献类型：
--
作者：
Howe, L.;Collett, M. G.;Pomroy, W. E.
犬新孢子虫是一种专性细胞内寄生虫，被认为是全世界牛流产的主要原因。已有绵羊自然感染犬新孢子虫的报道，但通常不被视为流产的重要原因。最近，新西兰发生了几起胎儿流产病例，其中检测到了犬新孢子虫，这强烈表明这些流产涉及新孢子虫。然而，有关新西兰羊群中自然发生的犬新孢子虫感染的流行情况，特别是其对繁殖成功率的影响的信息很少。因此，本研究通过确定 21 个存在不明原因流产问题的新西兰绵羊农场和 10 个生育水平始终较高的农场中存在的母羊血液和胎儿材料中犬新孢子虫抗体和 DNA 的流行情况，提供了关于新孢子虫在绵羊繁殖失败中所起作用的初步数据。这项研究的结果表明，总体血清阳性率为 1.4%，在流产/未怀孕 (1.8%)、年龄匹配的怀孕对照 (0.6%) 和高生育力 (2.1%) 母羊之间存在差异。然而，尽管观察到差异，三组之间没有统计学差异。此外，通过 PCR 在 13% 提交的胎儿大脑以及来自流产/未怀孕母羊 (6.9%)、年龄匹配怀孕对照母羊 (3.6%) 和高生育力怀孕母羊 (2.1%) 的母羊血液中检测到新孢子虫 DNA。当将 PCR 结果与 IFAT 和 IDEXX ELISA 结果考虑时，血清学阳性和 PCR 阳性血液样本之间没有相关性。总而言之，这些结果表明，仅依赖基于 ELISA 的血清学或 PCR 可能会低估新孢子虫的参与。此外，确定新孢子虫的参与似乎需要多方面的方法，其中诊断方法和血清学临界值可能需要随着有关羊宿主中犬新孢子虫自然感染影响的进一步信息的阐明而调整。 (C) 2011 Elsevier B.V. 保留所有权利。
Neospora caninum is an obligate intracellular parasite and is recognised as the leading cause of bovine abortion worldwide. Natural infection with N. caninum has been described in sheep but it has generally not been regarded as a significant cause of abortion. Recently, there have been several New Zealand cases of foetal abortions where N. caninum was detected which strongly suggested the involvement of Neospora in these abortions. However, there is minimal information about the prevalence of N. caninum infection naturally occurring in New Zealand sheep flocks and particularly its impact on reproduction success. Thus, this present study provides preliminary data on the role that Neospora is playing in ovine reproductive failure by establishing the prevalence of N. caninum antibodies and DNA in ewe blood and foetal material present in 21 New Zealand sheep farms with ongoing unexplained abortion problems and 10 farms with consistently high fertility levels. The results of this study demonstrated an overall seroprevalence of 1.4% which varied between Aborting/non-pregnant (1.8%), age-matched pregnant controls (0.6%) and high fertility (2.1%) ewes. However, despite the variation observed, there was no statistical difference between the three groups. In addition, Neospora DNA was detected by PCR in 13% of submitted foetal brains and in ewe blood from aborting/non-pregnant (6.9%), age-matched pregnant controls (3.6%) and high fertility pregnant (2.1%) ewes. When the PCR results were considered with the IFAT and IDEXX ELISA results, there was no correlation between serology positive and PCR positive blood samples. Taken together, these results reveal that reliance on ELISA-based serology or PCR alone may underestimate the involvement of Neospora. Furthermore, determining the involvement of Neospora appears to require a multi-facetted approach where diagnostic methods and serological cut-off values may need to be adjusted as further information about the effect of natural infections with N. caninum in the ovine host is elucidated. (C) 2011 Elsevier B.V. All rights reserved.