鸡呼肠孤病毒基因Ⅰ型变异株的分离鉴定和致病性分析OA北大核心

This study aimed to investigate the pathogen responsible for leg problems observed in broiler breeders at a chicken farm in Shandong Province,and to analyze its pathogenicity.Samples were collected from the affected chicken farm,and the investigation included embryonic chicken isolation,cell passage,reverse transcription-polymerase chain reaction(RT-PCR)detection,sequence analysis,pathogenicity tests on commercial broiler chickens,and immunoprotection assays.The results revealed the isolation of a strain of avian reovirus(ARV),named ARV-LL-2020,which exhibited 100％mortality in embryonic chickens and strong adaptability in Leghorn male hepatoma cell line(LMH).The ARV-LL-2020 strain belongs to genotype Ⅰ,similar to the classical S1 133 vaccine strain,with 73.6％nucleotide homology and 59.1％amino acid homology in the major antigen σC gene.In commercial broiler chickens,ARV-LL-2020 replicated symptoms identical to those observed in actual production settings.The commercial attenuated live vaccine strain S1 133 provided only 50％protection against ARV-LL-2020.These findings indicate that ARV-LL-2020 strain causing chicken leg problems is a variant strain of avian reovirus genotype Ⅰ,and the current commercial attenuated live vaccine S1 133 does not provide complete protection against it.