Stagegaard Julia, Kurth Andreas, Stern Daniel, Dabrowski Piotr Wojciech, Pocknell Ann, Nitsche Andreas, Schrick Livia
Ree Park-Safari, Ebeltoft, Denmark.
Centre for Biological Threats and Special Pathogens, Robert Koch Institute, Berlin, Germany.
PLoS One. 2017 Nov 9;12(11):e0187089. doi: 10.1371/journal.pone.0187089. eCollection 2017.
Cowpox virus infections in captive cheetahs (Acinonyx jubatus) with high morbidity and mortality have already been reported in the UK and Russia in the 1970s. However, most of the reported cases have been singular events. Here, we report a total of five cowpox virus outbreaks in cheetahs in the same safari park in Denmark between 2010 and 2014. Nine cheetahs showed varying severity of clinical disease; two of them died (22%). All episodes occurred between August and October of the respective year. No other carnivores kept at the same institution nor the keepers taking care of the animals were clinically affected. The clinical picture of cowpox was confirmed by extensive laboratory investigations including histopathological and molecular analyses as well as cell culture isolation of a cowpox virus. High anti-orthopoxvirus antibody titers were detected in all 9 diseased cheetahs compared to seven contact cheetahs without clinical signs and 13 cheetahs not in direct contact. Additionally, whole genome sequencing from one sample of each cluster with subsequent phylogenetic analysis showed that the viruses from different outbreaks have individual sequences but clearly form a clade distinct from other cowpox viruses. However, the intra-clade distances are still larger than those usually observed within clades of one event. These findings indicate multiple and separate introductions of cowpox virus, probably from wild rodent populations, where the virus keeps circulating naturally and is only sporadically introduced into the cheetahs. Sero-positivity of voles (Arvicola amphibious) caught in zoo grounds strengthens this hypothesis. As a consequence, recommendations are given for medical and physical management of diseased cheetahs, for hygienic measures as well as for pre-shipment isolation before cheetah export from zoo grounds.
20世纪70年代，英国和俄罗斯就已报道圈养猎豹（非洲猎豹）感染牛痘病毒，发病率和死亡率很高。然而，大多数报道的病例都是个别事件。在此，我们报告2010年至2014年期间，丹麦同一个野生动物园的猎豹共发生了5起牛痘病毒疫情。9只猎豹表现出不同程度的临床疾病；其中2只死亡（22%）。所有疫情均发生在各年份的8月至10月之间。同一机构饲养的其他食肉动物以及照顾这些动物的饲养员均未出现临床感染症状。通过广泛的实验室调查，包括组织病理学和分子分析以及牛痘病毒的细胞培养分离，确诊了牛痘的临床症状。与7只无临床症状的接触猎豹和13只未直接接触的猎豹相比，所有9只患病猎豹均检测到高抗正痘病毒抗体滴度。此外，对每个集群的一个样本进行全基因组测序，随后进行系统发育分析，结果表明，不同疫情中的病毒具有各自的序列，但明显形成一个与其他牛痘病毒不同的进化枝。然而，进化枝内的距离仍大于通常在一次事件的进化枝内观察到的距离。这些发现表明牛痘病毒有多次且独立的引入，可能来自野生啮齿动物种群，该病毒在其中自然传播，只是偶尔传播到猎豹身上。在动物园场地捕获的水田鼠（水䶄）血清阳性强化了这一假设。因此，针对患病猎豹的医疗和物理管理、卫生措施以及猎豹从动物园场地出口前的装运前隔离提出了建议。
