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      High prevalence of hepatitis E virus infection among domestic pigs in Ibaraki Prefecture, Japan

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          Hepatitis E virus (HEV) is prevalent in pigs and may serve as a reservoir for human infection. However, data on HEV infections in pigs in Ibaraki Prefecture, Japan, are limited. Here, we clarified the process and course of HEV in naturally infected pigs. Serum ( n = 160) and liver ( n = 110) samples were collected from pigs at the slaughterhouse. Furthermore, serum samples were collected from 45 breeding sows and serum and feces samples were collected from 7 piglets once a week (raised until 166 days of age). HEV antigen and antibodies were evaluated, and the genotype was identified based on molecular phylogenetic tree analysis.


          The samples collected from the slaughterhouse revealed that few pigs were HEV carriers but most possessed anti-HEV antibodies. Most breeding sows possessed antibodies, and the piglets excreted HEV on the farm at approximately 10 weeks of age. One pig was initially infected, and in a few weeks, the other pigs living in the same sty became infected.


          Most pigs in Ibaraki Prefecture were with HEV. On the farm, most piglets were infected with HEV by the time they reached slaughter age. We confirmed that HEV infection is successively transmitted among piglets living in the same sty.

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          Expression and self-assembly of empty virus-like particles of hepatitis E virus.

          Hepatitis E virus (HEV) is a pathogenic agent that causes fecally-orally transmitted acute hepatitis. The genome, a single-stranded positive-sense RNA, encodes three forward open reading frames (ORFs), in which an approximately 2-kb structural protein is located in the 3' end. To produce HEV-like particles the structural protein, with its N terminus truncated (amino acid residues 112 to 660 of ORF2), was expressed in insect Tn5 cells by a recombinant baculovirus. In addition to the primary translation product with a molecular mass of 58 kDa, a large amount of a further-processed molecule with a molecular mass of 50 kDa was generated and efficiently released into the culture medium. Electron microscopic observation of the culture medium revealed that the 50-kDa protein self-assembled to form empty virus-like particles (VLPs). The buoyant density of the VLPs in CsCl was 1.285 g/cm3 and their diameter was 23.7 nm, a little smaller than the 27 nm of native HEV particles secreted into the bile or stools of experimentally infected monkeys. The yield of the VLPs was 1 mg per 10(7) cells as a purified form. The particles possess antigenicity similar to that of authentic HEV particles and, consequently, they appear to be a good antigen for the sensitive detection of HEV-specific immunoglobulin G (IgG) and IgM antibodies. Furthermore, the VLP may be the most promising candidate yet for an HEV vaccine, owing to its potent immunogenicity.
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            Zoonotic and foodborne transmission of hepatitis E virus.

             Jin Meng (2013)
            Hepatitis E is an important disease in many developing countries of Asia and Africa with large explosive outbreaks and is also endemic with sporadic or cluster cases of hepatitis in many industrialized countries. The causative agent, hepatitis E virus (HEV), is currently classified in the family Hepeviridae. Thus far, four putative genera of HEV representing mammalian, avian, and fish species have been identified and characterized worldwide. Within the mammalian HEV that infects humans, genotypes 1 and 2 are associated with epidemics and restricted to humans, whereas genotypes 3 and 4 are zoonotic and associated with sporadic and cluster cases of hepatitis E. As a fecal-orally transmitted disease, waterborne transmission is still an important route of HEV transmission especially for large outbreaks associated with genotypes 1 and 2. However, genetic identification of numerous animal strains of HEV and the demonstrated ability of cross-species infection by these animal strains have significantly broadened the host range and diversity of HEV and raised public health concerns for zoonosis and food safety associated with genotypes 3 and 4 HEV infection. Pigs and likely other animal species serve as reservoirs for HEV. Direct contact with infected pigs and other animals and consumption of contaminated animal meat and meat products pose risks for HEV infection. In this article, the current understanding of the zoonotic and foodborne transmissions of HEV as well as strategies to prevent zoonosis and ensure food safety is discussed. Thieme Medical Publishers 333 Seventh Avenue, New York, NY 10001, USA.
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              Hepatitis E Virus Genotypes and Evolution: Emergence of Camel Hepatitis E Variants

              Hepatitis E virus (HEV) is a major cause of viral hepatitis globally. Zoonotic HEV is an important cause of chronic hepatitis in immunocompromised patients. The rapid identification of novel HEV variants and accumulating sequence information has prompted significant changes in taxonomy of the family Hepeviridae. This family includes two genera: Orthohepevirus, which infects terrestrial vertebrates, and Piscihepevirus, which infects fish. Within Orthohepevirus, there are four species, A–D, with widely differing host range. Orthohepevirus A contains the HEV variants infecting humans and its significance continues to expand with new clinical information. We now recognize eight genotypes within Orthohepevirus A: HEV1 and HEV2, restricted to humans; HEV3, which circulates among humans, swine, rabbits, deer and mongooses; HEV4, which circulates between humans and swine; HEV5 and HEV6, which are found in wild boars; and HEV7 and HEV8, which were recently identified in dromedary and Bactrian camels, respectively. HEV7 is an example of a novel genotype that was found to have significance to human health shortly after discovery. In this review, we summarize recent developments in HEV molecular taxonomy, epidemiology and evolution and describe the discovery of novel camel HEV genotypes as an illustrative example of the changes in this field.

                Author and article information

                +81-29-241-6652 ,
                BMC Vet Res
                BMC Vet. Res
                BMC Veterinary Research
                BioMed Central (London )
                12 March 2019
                12 March 2019
                : 15
                [1 ]Ibaraki Prefectural Institute of Public Health, Mito, Ibaraki 310-0852 Japan
                [2 ]ISNI 0000 0000 9206 2938, GRID grid.410786.c, Laboratory of Laboratory Animal Science and Medicine, Faculty of Veterinary Medicine, , Kitasato University, ; Towada, Aomori Japan
                [3 ]Swine Laboratory, Ibaraki Prefectural Livestock Research Center, Inashiki, Ibaraki Japan
                [4 ]ISNI 0000 0001 2220 1880, GRID grid.410795.e, Department of Virology II, , National Institute of Infectious Diseases, ; Musashimurayama, Tokyo Japan
                © The Author(s). 2019

                Open AccessThis article is distributed under the terms of the Creative Commons Attribution 4.0 International License (, which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The Creative Commons Public Domain Dedication waiver ( applies to the data made available in this article, unless otherwise stated.

                Research Article
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                © The Author(s) 2019

                Veterinary medicine

                slaughterhouse, piglets, ibaraki prefecture, hepatitis e virus


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