Laboratory Diagnosis of four Cases of Avian Hepatitis E andPhylogenetic Analysis on Its ORF2 Gene
In the study,throughdiagnostic technology of molecular epidemiology,liverand spleen samples were collected from sick chickens with symptoms of hepatitisin four farms in Shandong,Liaoning,Jilin and Shaanxi provinces,then avian hepatitisE virus(aHEV) was detected byRT-PCR and the fragments of aHEV-ORF2 gene were sequenced. At last,the homology was compared by means of MegAlign. The resultsshowed that all samples from the above four farms were positive for aHEV,and the homology between the gene sequences ranged from 84.5% to94.5%. In addition,the homologies of the four isolatedstrains with four already published genotypes were all less than 84.0%,specifically,the homologies with genotypeHEV 1(Australian and Korean strains),HEV 2(American prototype and Americanvirus-free strains),HEV 3(Europeanand Chinese strains),HEV 4(Hungarianand Taiwanese-chinese strains)were 81.6% to 82.8%,80.9% to 82.8%,80.8% to 82.5% and 81.4% to82.6%,respectively. According to the analysis of evolutionarytree of ORF2 gene,the four strains of aHEV allbelonged to B type of hepatitis E,instead of the fourreported genotypes,which formed a new separate genebranch,indicating a new genotype was prevalent inChina. The research would provide some references and foundation for furtherstudy of aHEV in China.