Full-length sequence of genotype 3 hepatitis E virus derived from a pig in Thailand

Authors

  • Uamporn Siripanyaphinyo,

    1. Thailand-Japan Research Collaboration Center on Emerging and Re-emerging Infections (RCC-ERI)
    2. Department of Virology, Research Institute for Microbial Diseases, Osaka University, Osaka, Japan
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  • Dusit Laohasinnarong,

    1. Faculty of Veterinary Science, Mahidol University, Nakhon Pathom, Thailand
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  • Juthamas Siripanee,

    1. National Institute of Health, Department of Medical Sciences, Ministry of Public Health, Nonthaburi, Thailand
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  • Kampon Kaeoket,

    1. Faculty of Veterinary Science, Mahidol University, Nakhon Pathom, Thailand
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  • Masanori Kameoka,

    1. Thailand-Japan Research Collaboration Center on Emerging and Re-emerging Infections (RCC-ERI)
    2. Department of Virology, Research Institute for Microbial Diseases, Osaka University, Osaka, Japan
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  • Kazuyoshi Ikuta,

    Corresponding author
    1. Thailand-Japan Research Collaboration Center on Emerging and Re-emerging Infections (RCC-ERI)
    2. Department of Virology, Research Institute for Microbial Diseases, Osaka University, Osaka, Japan
    • Department of Virology, Research Institute for Microbial Diseases, Osaka University, 3-1 Yamada-oka, Suita, Osaka 565-0871, Japan.
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  • Pathom Sawanpanyalert

    1. National Institute of Health, Department of Medical Sciences, Ministry of Public Health, Nonthaburi, Thailand
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  • RCC-ERI is established by Research Institute for Microbial Diseases, Osaka University, Japan and National Institute of Health, Department of Medical Sciences, Ministry of Public Health, Thailand.

Abstract

Hepatitis E virus (HEV) infection in pigs was investigated in two principal swine farming areas in Thailand. Anti-HEV antibodies and HEV RNA in sera were examined in 258 pigs reared on five commercial farms from age 1 to 6.5 months and sows. Overall, 167 of 258 (64.7%) pigs were positive for anti-HEV IgG, while 20 of 258 (7.75%) had detectable HEV RNA. Sequence analysis of 20 HEV isolates obtained from viremic pigs revealed that they were 92.3–100% identical to each other and had 82.2–88.2% nucleotide similarity to other reported genotype 3 isolates in 415 nucleotide sequences within ORF2 region. Further characterization by sequencing the complete genome of the Thai swine HEV isolate (named Thai-swHEV07) and phylogenetic analysis showed that Thai-swHEV07 segregated into a cluster consisting of swine isolates from Japan, Mongolia, and Kyrgyzstan within the HEV genotype 3. The Thai-swHEV07 had a genomic length of 7,229 nt excluding the polyadenylated region at 3′ terminus of the genome. Comparison of Thai-swHEV07 and 27 reported strains of genotype 3 revealed 80.4–85.9% nucleotide identity, with the highest identity of 85.9% to the novel swHEV strain from Mongolia. These findings suggest that genotype 3 HEV isolates are markedly heterogeneous. J. Med. Virol. 81:657–664, 2009 © 2009 Wiley-Liss, Inc.

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