Kansas State University Veterinary Diagnostic Laboratory, Department of Diagnostic Medicine/Pathobiology, College of Veterinary Medicine, Kansas State University, Manhattan, Kansas, 66506, USA.
BMC Vet Res. 2020 Jul 13;16(1):241. doi: 10.1186/s12917-020-02464-7.
The present report describes a case of pseudocowpox virus (PCPV) infection in a seven-year-old female bison euthanized due to a history of declining condition and sores on the vulva and udder.
External examination revealed multifocal, raised, keratinized plaques (0.5-2 cm) covering the skin of the ventral surface of the tail, perineum, caudoventral abdomen, udder, both inguinal recesses, and the medial aspects of both thighs. No significant gross lesions were present in the reminder of the tissues examined. Histopathological examination of the affected skin showed moderate epidermal hyperplasia with rete pegs, marked parakeratotic hyperkeratosis with crusts of degenerate neutrophils and cell debris, and few epithelial cells undergoing ballooning degeneration with occasional eosinophilic intracytoplasmic inclusion bodies (3-5 μm Bollinger body). Negative staining electron microscopy from skin revealed typical Parapoxvirus (PPV) particles, which were also confirmed by real-time PCR (Ct =18.6). Metagenomic analysis of the skin samples revealed only poxviruses. The bison parapox B2L envelope gene clustered with other parapox sequences identified from ruminants.
This is the first report of PCPV virus infection in an American bison. Identification of novel susceptible hosts of parapox viruses sheds light on the viral evolution and highlights the importance of potential economic impact of this disease to the bison industry.
本报告描述了一例因状态下降和外阴及乳房出现溃疡而被安乐死的 7 岁雌性野牛感染伪牛痘病毒（PCPV）的病例。
外部检查显示，尾巴腹侧表面、会阴部、尾腹侧腹部、乳房、两个腹股沟隐窝以及两个大腿内侧有多个、凸起、角化斑块（0.5-2 厘米），覆盖皮肤。检查的其余组织没有明显的大体病变。受影响皮肤的组织病理学检查显示中度表皮增生，有钉突，明显的角化不全性角化过度，有坏死中性粒细胞和细胞碎片的结痂，以及少数上皮细胞发生气球样变性，偶尔有嗜酸性细胞质内包涵体（3-5μm 博林格体）。皮肤的负染电子显微镜显示典型的副痘病毒（PPV）颗粒，这也通过实时 PCR（Ct =18.6）得到了证实。皮肤样本的宏基因组分析仅显示痘病毒。野牛副痘 B2L 包膜基因与从反刍动物中鉴定出的其他副痘序列聚类。
这是首例在美国野牛中发现的 PCPV 病毒感染。鉴定出副痘病毒的新易感宿主，揭示了病毒进化的情况，并强调了这种疾病对野牛产业潜在经济影响的重要性。
