Abstract：
Congenital malformations occur sporadically in cattle; however, congenital structural and functional disorders of the nervous system are rather common in ruminants. Among the numerous causes of congenital nervous system defects, infectious agents are highlighted in this paper. Virus-induced congenital malformations are well known, among which those caused by bovine viral diarrhoea virus (BVDV), Akabane virus (AKAV), Schmallenberg virus (SBV), Bluetongue virus (BTV), and Aino virus (AV) are the most studied. In this study, we specify and categorise macroscopic and histopathological lesions in the brain of 42 newborn calves suffering from severe neurologic signs and diagnosed with BVDV and AKAV infection. Following a complete necropsy, specimens were collected from the brains to track the presence of BVDV, AKAV and SBV utilising reverse transcription polymerase chain reaction. Of the 42 examined calves, 21 were BVDV positive and 6 were AKAV positive, while 15 brains were negative for the studied agents. Regardless of the aetiology, cerebellar hypoplasia, hydranencephaly, hydrocephalus, porencephaly, and microencephaly were detected. Cerebellar hypoplasia was the most common lesion seen in both BVDV-positive and AKAV-positive cases. Virus-induced necrosis of the germinative cells of the external granular layer of cerebellum, as well as vascular damages, are believed to be the underlying causes of cerebellar hypoplasia. BVDV was the most important aetiological agent of such cases in this study.
摘要：
先天性畸形偶尔发生在牛身上；然而，神经系统的先天性结构和功能紊乱在反刍动物中相当常见。在先天性神经系统缺陷的众多原因中，本文重点介绍了传染性病原体。病毒引起的先天畸形是众所周知的,其中由牛病毒性腹泻病毒（BVDV）引起的，Akabane病毒(AKAV),施马伦贝格病毒(SBV)蓝舌病毒（BTV），和爱诺病毒（AV）是研究最多的。在这项研究中,我们对42例患有严重神经系统征象并被诊断为BVDV和AKAV感染的新生小牛的脑宏观和组织病理学病变进行了指定和分类.完整尸检后,从大脑中收集样本以追踪BVDV的存在，AKAV和SBV利用逆转录聚合酶链反应。在42只接受检查的小牛中，21例BVDV阳性，6例AKAV阳性，而15个大脑对所研究的药物呈阴性。不管病因是什么，小脑发育不全,无脑积水,脑积水,头颅后,并检测到小脑。小脑发育不全是BVDV阳性和AKAV阳性病例中最常见的病变。病毒诱导的小脑外部颗粒层的发芽细胞坏死，以及血管损伤，被认为是小脑发育不全的根本原因。在本研究中，BVDV是此类病例的最重要病因。
