Epidemiological Investigation and Histopathological Observation of HEV in Xizang Pig
To understand the prevalence of hepatitis E virus(HEV)in Xizang pigs,this study collected 313 serum samples from Tibetan pigs and 53 liver samples from York pigs in Linzhi,Xizang.HEV-IgG antibodies in Tibetan pig serum were detected and analyzed using t-tests,while liver samples from York pigs were tested for the conserved region of the HEV open reading frame(ORF2)gene using reverse transcription-polymerase chain reaction(RT-PCR).Positive RT-PCR products were sequenced for phylogenetic and homology analysis to determine the HEV genotypes in Xizang pigs.Quantitative real-time PCR(qPCR)and hematoxylin-eosin(H.E.)staining were used for pathogen quantification and pathological analysis of positive liver tissues.The results showed an overall positive rate of HEV-IgG antibodies of 35.46％(111/313)in Tibetan pig serum samples.Among them,the antibody positive rates for boars and sows were 39.31％(68/173)and 30.71％(43/140),respectively.The antibody positive rates for piglets aged 1-2 months,nursing pigs aged 2-4 months,fattening pigs aged 4-6 months,and pigs over 8 months were 27.87％(17/61),32.93％(27/82),43.00％(43/100),and 34.29％(24/70),respectively.Two HEV RNA-positive samples were identified from York pig liver tissues,named TLZyork1 and TLZyork2,with GenBank accession numbers PP464289 and PP464290,and viral loads of 3.15×103 and 2.81×104copies/mL,respectively.Homology analysis revealed 73.9％-97.4％similarity with HEV genotypes 4a,4b,4c,and 4d,while phylogenetic tree analysis indicated that TLZyork1 and TLZyork2 belong to the HEV 4d genotype.H.E.staining of HEV RNA-positive liver tissues showed extensive hepatocyte edema,ballooning degeneration of hepatocytes around the central vein,and mild lymphocyte infiltration.In conclusion,HEV is prevalent among Tibetan and York pigs in Xizang,highlighting the need for enhanced control measures to mitigate HEV infection in this region.
Tibetan pigYork pighepatitis E virus(HEV)epidemiologic investigationhistopathological staining
万方数据
维普
