Department of Pathology, University of Veterinary Medicine Hannover, Foundation, Hanover, Germany.
Research Center for Emerging Infections and Zoonoses, University of Veterinary Medicine Hannover, Foundation, Hanover, Germany.
Sci Rep. 2022 Aug 29;12(1):14691. doi: 10.1038/s41598-022-19023-9.
In the last fifteen years, an epidemic of canine distemper virus (CDV) with marked neurotropism has occurred in Europe after a longer period of endemic transmission. Many wildlife species have been infected, with red foxes (Vulpes vulpes) being particularly affected. Given that this species is assumed to mediate cross-species CDV infections to domestic and wild animals, tissue samples from foxes with confirmed CDV infection in North-Western Germany were investigated to better understand the neurotropic aspects of the disease. This analysis included histopathology, virus distribution and cell tropism, phenotyping of inflammatory responses and determination of the genotype of the viruses based on the phylogeny of the hemagglutinin (H) gene. The predominant lesion type is gliosis in both gray and white matter areas associated with an accumulation of Iba1 macrophages/microglia and upregulation of major histocompatibility complex class II molecules in the brain, while sequestration of CD3 T and Pax5 B cell in CDV-infected foxes is limited. Demyelination is found in few foxes, characterized by reduced myelin staining with loss of CNPase oligodendrocytes in the cerebellar white matter and brainstem. In addition, axonal damage, characterized by β-amyloid precursor protein expression, is found mainly in these brain regions. In situ hybridization reveals a primary infection of the cerebral and cerebellar gray matter and brain stem. Iba1 cells and NeuN neurons represent the main CDV targets. Sequencing of the CDV H open reading frame from fox tissues reveals that the virus strains belongs to three different sub-lineages of the Europe-1/South America-1 genotype, suggesting independent transmission lines.
在过去的十五年中，一种具有明显嗜神经性的犬瘟热病毒（CDV）在欧洲流行，此前该病毒已经在较长时间内处于地方性传播状态。许多野生动物物种都受到了感染，其中红狐（Vulpes vulpes）受到的影响尤为严重。鉴于这种物种被认为可以介导跨物种的 CDV 感染，包括家养和野生动物，因此对来自德国西北部确诊为 CDV 感染的狐狸的组织样本进行了调查，以更好地了解这种疾病的嗜神经性方面。该分析包括组织病理学、病毒分布和细胞嗜性、炎症反应的表型以及基于血凝素（H）基因的系统发育确定病毒的基因型。主要的病变类型是灰质和白质区域的神经胶质增生，伴有 Iba1 巨噬细胞/小胶质细胞的积累和大脑中主要组织相容性复合体 II 分子的上调，而在 CDV 感染的狐狸中 CD3 T 和 Pax5 B 细胞的隔离是有限的。脱髓鞘在少数狐狸中发现，其特征是小脑白质和脑干中少突胶质细胞的髓鞘染色减少，以及 CNPase 减少。此外，还发现了以β-淀粉样前体蛋白表达为特征的轴突损伤，主要出现在这些大脑区域。原位杂交显示大脑和小脑灰质以及脑干的原发性感染。Iba1 细胞和 NeuN 神经元是 CDV 的主要靶标。从狐狸组织中 CDV H 开放阅读框的测序显示，病毒株属于欧洲-1/南美洲-1 基因型的三个不同亚谱系，表明存在独立的传播线。
