Prevalence of Hepatitis E Virus in Swine Fed on Kitchen Residue

Peng Xiao,Ruiwen Li,Quan Sun,Ruiping She,Jun Yin,Wengui Li,Jingjing Mao,Houssam Attoui

doi:10.1371/journal.pone.0033480

Peng Xiao, Ruiwen Li + Show 6 more

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https://doi.org/10.1371/journal.pone.0033480

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Abstract

The aim of this study was to investigate the prevalence of swine hepatitis E virus (HEV) in pigs fed different feedstuffs (kitchen residue or mixed feeds) and genetic identification of HEV isolated in Hebei province, China. Serum and fecal samples were collected from adult swine. Anti-HEV antibody was evaluated by double sandwich antigen enzyme immunoassay. HEV RNA was extracted from fecal samples and amplified by nested RT-PCR. The reaction products were sequenced, and the sequence analyzed. Virus-like particles were distinguishable by negative staining in the electron microscope. Histopathological observation and immunohistochemical localization were used in the animal models. Overall, the anti-HEV positive percentage of serum samples from pigs fed on kitchen residue was 87.10% (27/31), and 53.06% (130/245) from pigs fed on complete feed. The HEV RNA positivity rate of fecal samples from pigs fed on kitchen residue was 61.54% (8/13), but zero for pigs fed on complete feed. Sequence analysis of these eight samples and comparison with the published sequence showed that there were eight groups that belonged to genotype 4 d and the nucleotide identity was 95.6–99.3%. swHE11 is most closely related to strain CCC220, and the other seven HEV isolates were most closely related to strains swGX40, SwCH189 and V0008ORF3, which are isolates from human and pigs. Histopathological observation showed that there was liver damage in the experimental group, and immunohistochemistry indicated that the HEV antigens were strongly positive at 7 days after infection. The results demonstrated that the prevalence of HEV in pigs fed on kitchen residue was higher than in those fed on complete feed (P<0.05).

Highlights

Hepatitis E virus (HEV), the causative agent of hepatitis E, has a single-stranded, positive-sense RNA genome within a nonenveloped capsid [1]
We investigated HEV infection among swine fed with kitchen residue by ELISA and nested RT-PCR in Hebei province, and compared it with HEV prevalence in pigs fed with complete feed
AntiHEV antibodies were detected in 87.10% (27/31) of pigs fed with swill, but the rate was only 53.06% (130/245) in pigs fed with feeder

Summary

Introduction

Hepatitis E virus (HEV), the causative agent of hepatitis E, has a single-stranded, positive-sense RNA genome within a nonenveloped capsid [1]. Hepatitis E is endemic in human populations in many developing regions of the world including Asia, Africa and Latin America [5,6,7,8,9,10,11,12]. In those regions, the disease is a serious public health problem. HEV infection is sporadic in humans but has become increasingly important [14,15,16,17,18,19]

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