McKenny L, O'Handley R, Kovaliski J, Mutze G, Peacock D, Lanyon S
School of Animal and Veterinary Sciences, The University of Adelaide, Roseworthy, South Australia, Australia.
Invasive Species, Biosecurity SA, Primary Industries and Regions SA, Urrbrae, South Australia, Australia.
Aust Vet J. 2020 Aug;98(8):380-387. doi: 10.1111/avj.12951. Epub 2020 Apr 30.
The aim of this study was to utilise wild rabbits (Oryctolagus cuniculus) as a sentinel species to study levels of environmental contamination with N. caninum and T. gondii in South Australia, and to examine associations with rainfall, climate and land use.
Toxoplasma gondii (T. gondii), an apicomplexan parasite, causes the clinical disease toxoplasmosis, which can affect sheep as well as humans and many other animals. Neosporosis, the clinical disease caused by closely related Neospora caninum (N. caninum), causes abortions in cattle, with large economic impacts to cattle industries.
Aliquots of wild rabbit (Oryctolagus cuniculus) serum were obtained from twelve sites across South Australia over a period of eighteen years, with a total of 2114 samples. An in-house Modified Agglutination Test (MAT) was developed, and samples were screened for the specific antibodies against both T.gondii and N. caninum.
Overall, 9.9% of samples screened for T. gondii tested positive and 6.1% of samples screened for N. caninum tested positive. There was no difference observed in seroprevalence of T.gondii specific antibodies between samples collected throughout summer, autumn, winter or spring. By contrast, a significantly higher (p=0.030) seroprevalence of N. caninum specific antibodies was observed in spring than any other season. T. gondii and N. caninum antibodies were discovered at sites across a broad area of South Australia, indicating these environments maybe infected with both parasites.
Results provide evidence that suggests N. caninum oocysts may have different survival characteristics, such as varying tolerances to low relative humidity, than T. gondii oocysts.
本研究旨在利用野兔（穴兔）作为哨兵物种，研究南澳大利亚州环境中犬新孢子虫和弓形虫的污染水平，并探讨其与降雨、气候和土地利用的关系。
弓形虫是一种顶复门寄生虫，可引发临床疾病弓形虫病，可影响绵羊以及人类和许多其他动物。新孢子虫病是由密切相关的犬新孢子虫引起的临床疾病，可导致牛流产，对养牛业造成巨大经济影响。
在18年的时间里，从南澳大利亚州的12个地点采集了野兔血清样本，共2114份。开发了一种内部改良凝集试验（MAT），并对样本进行筛选，以检测针对弓形虫和犬新孢子虫的特异性抗体。
总体而言，筛查弓形虫的样本中有9.9%呈阳性，筛查犬新孢子虫的样本中有6.1%呈阳性。在整个夏季、秋季、冬季或春季采集的样本中，弓形虫特异性抗体的血清阳性率没有差异。相比之下，春季犬新孢子虫特异性抗体的血清阳性率显著高于其他任何季节（p=0.030）。在南澳大利亚州的大片地区都发现了弓形虫和犬新孢子虫抗体，表明这些环境可能同时感染了这两种寄生虫。
结果提供了证据，表明犬新孢子虫卵囊可能具有与弓形虫卵囊不同的生存特征，例如对低相对湿度的耐受性不同。
