Li Zi, He Wenqi, Lan Yungang, Zhao Kui, Lv Xiaoling, Lu Huijun, Ding Ning, Zhang Jing, Shi Junchao, Shan Changjian, Gao Feng
Key Laboratory of Zoonosis, Ministry of Education, College of Veterinary Medicine, Jilin University, Jilin, China.
Key Laboratory of Zoonosis, Ministry of Education, Institute of Zoonosis, Jilin University, Jilin, China.
PeerJ. 2016 Sep 15;4:e2443. doi: 10.7717/peerj.2443. eCollection 2016.
An acute outbreak of porcine hemagglutinating encephalomyelitis virus (PHEV) infection in piglets, characterized with neurological symptoms, vomiting, diarrhea, and wasting, occurred in China. Coronavirus-like particles were observed in the homogenized tissue suspensions of the brain of dead piglets by electron microscopy, and a wild PHEV strain was isolated, characterized, and designated as PHEV-CC14. Histopathologic examinations of the dead piglets showed characteristics of non-suppurative encephalitis, and some neurons in the cerebral cortex were degenerated and necrotic, and neuronophagia. Similarly, mice inoculated with PHEV-CC14 were found to have central nervous system (CNS) dysfunction, with symptoms of depression, arched waists, standing and vellicating front claws. Furthmore, PHEV-positive labeling of neurons in cortices of dead piglets and infected mice supported the viral infections of the nervous system. Then, the major structural genes of PHEV-CC14 were sequenced and phylogenetically analyzed, and the strain shared 95%-99.2% nt identity with the other PHEV strains available in GenBank. Phylogenetic analysis clearly proved that the wild strain clustered into a subclass with a HEV-JT06 strain. These findings suggested that the virus had a strong tropism for CNS, in this way, inducing nonsuppurative encephalitis as the cause of death in piglets. Simultaneously, the predicted risk of widespread transmission showed a certain variation among the PHEV strains currently circulating around the world. Above all, the information presented in this study can not only provide good reference for the experimental diagnosis of PHEV infection for pig breeding, but also promote its new effective vaccine development.
中国发生了一起仔猪急性猪血凝性脑脊髓炎病毒（PHEV）感染疫情，其特征为出现神经症状、呕吐、腹泻和消瘦。通过电子显微镜在死亡仔猪大脑的匀浆组织悬液中观察到冠状病毒样颗粒，并分离、鉴定出一株野生PHEV毒株，命名为PHEV-CC14。对死亡仔猪进行的组织病理学检查显示出非化脓性脑炎的特征，大脑皮层中的一些神经元发生变性和坏死，并出现噬神经元现象。同样，接种PHEV-CC14的小鼠出现中枢神经系统（CNS）功能障碍，表现为抑郁、弓背、站立和前爪抽搐等症状。此外，死亡仔猪和感染小鼠大脑皮层中神经元的PHEV阳性标记支持了神经系统的病毒感染。然后，对PHEV-CC14的主要结构基因进行测序和系统发育分析，该毒株与GenBank中其他PHEV毒株的核苷酸同一性为95%-99.2%。系统发育分析清楚地证明，该野生毒株与HEV-JT06毒株聚集在一个亚类中。这些发现表明，该病毒对中枢神经系统具有强烈的嗜性，以此诱导非化脓性脑炎成为仔猪死亡的原因。同时，预测的广泛传播风险在目前全球流行的PHEV毒株之间存在一定差异。最重要的是，本研究提供的信息不仅可为养猪业PHEV感染的实验诊断提供良好参考，还可推动其新型有效疫苗的研发。
