新型鸭肝炎病毒的分离鉴定及VP1基因序列分析

摘要

为了解新型鸭肝炎病毒(N-DHV)的变异情况,本实验从广西、河南、山东临床发病鸭体内分离到3株病毒.通过RT-PCR检测为N-DHV.将分离株进行鸭胚传代培养,并测定鸭胚毒的ELD50为10-3.29/0.2 mL～10-465/0.2 mL.以1型和N-DHV阳性血清分别与分离株进行血清交叉中和试验,结果表明,Ⅰ型鸭肝炎病毒(DHV-1)阳性血清对分离株无保护性.动物回归试验表明,分离株致死雏鸭的临床症状和病变与DHV-1相同,分离株的致死率为30％～70％.将分离株接种鸡胚,不产生任何病变,在鸡胚成纤维细胞中连续传5代后,细胞产生明显、规律的病变.扩增3株分离株的VP1基因,并进行氨基酸序列比对,结果表明3个分离株与DHV-C的同源性最高,与DHV-A的同源性最低,并存在氨基酸的插入和缺失.本实验表明3个分离株与韩国N-DHV属于同一血清型.%To investigate the genetic diversity of new serotype of duck hepatitis virus (N-DHV), three virus isolates were isolated from dead ducks in Guangxi, Henan and Shandong provinces. The virus was identified as N-DHV by RT-PCR and neutralization tests with serotype 1 DHV positive serum. The isolates were passed in duck embryos and the titers were 10-3.29 ELDV 0.2 Ml to 10-4.65 ELDs/0.2 Ml. Typical clinical signs and pathological changes were observed when the isolates was inoculated to ducklings, resulting in 30% to 70% mortality. Furthermore, based on the deduced amino acid sequences, the phylogenetic analysis indicated that the isolates were highly homologous with DHV-C and low homologous with DHV-A.Therefore, the isolates could be classified into the same serotype of DHV isolated in Korea.