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Prevalence of hepatitis E virus ( HEV ) infection in various pig farms from Shaanxi Province, China: First detection of HEV RNA in pig semen
Author(s) -
Li Huixia,
Wu Junyuan,
Sheng Yamin,
Lu Qizhong,
Liu Baoyuan,
Chen Yiyang,
Sun Yani,
Zhou EnMin,
Zhao Qin
Publication year - 2019
Publication title -
transboundary and emerging diseases
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.392
H-Index - 63
eISSN - 1865-1682
pISSN - 1865-1674
DOI - 10.1111/tbed.12966
Subject(s) - biology , hepatitis e virus , genotype , virology , phylogenetic tree , veterinary medicine , serology , gene , antibody , genetics , medicine
Abstract The zoonotic transmission of hepatitis E virus ( HEV ) is mainly mediated by HEV genotypes 3 and 4, with domestic pigs serving as an important reservoir for both genotypes. In China, genotype 4 HEV is the primary prevalent genotype on pig farms. In this study, the prevalence of HEV infection in pig herds of Shaanxi Province was investigated. Serological testing detected anti‐ HEV antibody‐positive pigs in five selected cities, with 13 of 17 farms harbouring at least one positive pig (76.47%). Within positive farms, the proportion of positive pigs ranged from 1.6% to 37.5%. Genetic detection analyses of faecal samples revealed that pigs in four cities and on nine of 17 farms were positive for sequences homologous to a partial ORF 2‐coding region of HEV (306 bp), as were 6 of 53 bile and 1 of 26 semen samples. Meanwhile, DNA coding for partial HEV ORF 1 (1,080 bp) and a longer gene segment coding for partial ORF 2 (1,594 bp) were successfully amplified from RNA isolated from pig semen from one HEV ‐positive pig. Sequence comparisons of partial ORF 2 gene sequences showed that HEV isolates from Shaanxi Province shared the highest identity (81.4%–96.1%) with genotype 4 HEV . Phylogenetic tree analysis grouped these isolates into three subgenotypes (4d, 4h and 4i), with subgenotype 4i the predominant subgenotype. In addition, the HEV isolate from pig semen belonged to subgenotype 4i HEV based on phylogenetic trees constructed both using partial ORF 1 and ORF 2 gene sequences. In conclusion, HEV infection is endemic on pig farms of Shaanxi Province, China, and 4i is the predominant HEV subgenotype. More important, this is the first study demonstrating detection of HEV RNA in pig semen, suggesting that artificial insemination can transmit HEV in pigs.