Squirrelpox Virus: Assessing Prevalence, Transmission and Environmental Degradation
Squirrelpox Virus: Assessing Prevalence, Transmission and Environmental Degradation
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DOI：
10.1371/journal.pone.0089521
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发表时间：
2014-02-21
期刊：
影响因子：
3.7
通讯作者：
Reid, Neil
中科院分区：
文献类型：
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作者：
Collins, Lisa M.;Warnock, Neil D.;Reid, Neil
红松鼠（Sciurus vulgaris）在英国和爱尔兰下降，在过去的世纪，由于栖息地的丧失和引进的灰松鼠（Sciurus carolinensis），这竞争性地排除了红松鼠，并作为一个水库松鼠痘病毒（SQPV）。这种疾病通常对红松鼠是致命的，在病毒存在的地方，灰松鼠对它们的生态取代速度快25倍。我们旨在确定：（1）在区域范围内，SQPV DNA在入侵物种和本地物种中的血清阳性率和流行率;（2）SQPV可能的传播途径;（3）不同环境条件下的病毒降解速率。采集灰色（n = 208）和红色（n = 40）松鼠血液和组织样本。酶联免疫吸附试验（ELISA）和定量实时聚合酶链反应（qPCR）技术分别确定了血清阳性和病毒DNA存在。总体而言，8%的松鼠样本（两个物种合并）在其组织中有SQPV DNA的证据，22%的松鼠拥有抗体。抽样红松鼠的SQPV患病率为2.5%。与红松鼠相比，灰松鼠的病毒载量通常较低。春、夏季阳性检出率高于冬季。通过粪便（仅红松鼠）、尿液和体外寄生虫（两种物种）中存在病毒DNA，确定了可能的传播途径。病毒降解分析表明，在暴露于六种环境组合30天后，在温暖（25摄氏度）和干燥条件下的结痂中有更多的完整病毒颗粒，而不是在较冷（5和15摄氏度）或潮湿条件下。我们的结论是，SQPV是目前在入侵灰松鼠种群的发病率较低，在本地红松鼠的发病率较低。病毒传播可能通过尿液发生，特别是在温暖干燥的夏季条件下，但更值得注意的是，通过外寄生虫，这是两个物种共享。
Red squirrels (Sciurus vulgaris) declined in Great Britain and Ireland during the last century, due to habitat loss and the introduction of grey squirrels (Sciurus carolinensis), which competitively exclude the red squirrel and act as a reservoir for squirrelpox virus (SQPV). The disease is generally fatal to red squirrels and their ecological replacement by grey squirrels is up to 25 times faster where the virus is present. We aimed to determine: (1) the seropositivity and prevalence of SQPV DNA in the invasive and native species at a regional scale; (2) possible SQPV transmission routes; and, (3) virus degradation rates under differing environmental conditions. Grey (n = 208) and red (n = 40) squirrel blood and tissues were sampled. Enzyme-linked immunosorbent assay (ELISA) and quantitative real-time polymerase chain reaction (qPCR) techniques established seropositivity and viral DNA presence, respectively. Overall 8% of squirrels sampled (both species combined) had evidence of SQPV DNA in their tissues and 22% were in possession of antibodies. SQPV prevalence in sampled red squirrels was 2.5%. Viral loads were typically low in grey squirrels by comparison to red squirrels. There was a trend for a greater number of positive samples in spring and summer than in winter. Possible transmission routes were identified through the presence of viral DNA in faeces (red squirrels only), urine and ectoparasites (both species). Virus degradation analyses suggested that, after 30 days of exposure to six combinations of environments, there were more intact virus particles in scabs kept in warm (25 degrees C) and dry conditions than in cooler (5 and 15 degrees C) or wet conditions. We conclude that SQPV is present at low prevalence in invasive grey squirrel populations with a lower prevalence in native red squirrels. Virus transmission could occur through urine especially during warm dry summer conditions but, more notably, via ectoparasites, which are shared by both species.