Prevalence and genotype/subtype distribution of hepatitis E virus (HEV) among wild boars in Japan: Identification of a genotype 5 HEV strain

Takahashi, Masaharu; Nishizawa, Tsutomu; Sato, Yukihiro; Miyazaki, Shinichi; Aikawa, Tatsuya; Ashida, Kozo; Tamaru, Tomoko; Oguro, Kunihiko; Hayakawa, Fumihiro; Matsuoka, Hiroyuki; Ozaki, H; Kodera, Yuuji; Irokawa, Masahiko; Hirose, Hideo; Nagashima, Shigeo; Kawakami, Manri; Mizuo, Hitoshi; Okamoto, Hiroaki; Murata, Kazumoto

doi:10.1016/j.virusres.2020.198106

Cited by 28 publications

(18 citation statements)

References 63 publications

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“…Phylogenetic analysis based on HEV complete genomic sequences was also performed with the ML method in MEGA v7.0, and the best fit substitution model of Tamura–Nei model was calculated with Model Finder. As depicted in Figure 2b, the seven Chinese wild boar HEV strains were grouped into subtypes HEV‐4d, 4g, and 4h with HEV‐4d as the predominant genotype (Figure 2b), but no HEV‐3 strains were identified in the wild boars collected in this study probably because of the low sample numbers, although both HEV‐3 and HEV‐4 strains were found to be prevalent in the domestic pigs in China (subtypes 3b, 3d, and 4a‐4i) (Liu et al., 2016), and in wild boars from South Korea (subtypes 3a, 4a, and 4d) with 1.29% samples as positive (24/1859) and from Japan (subtypes 3a, 3b, 3e, 4c, 4g, 4i, and 5) with 3.9% as positive (74/1880) (Choe et al., 2020; Takahashi et al., 2020).…”

Section: Figurementioning

confidence: 99%

“…subtypes HEV-4d, 4g, and 4h with HEV-4d as the predominant genotype (Figure 2b), but no HEV-3 strains were identified in the wild boars collected in this study probably because of the low sample numbers, although both HEV-3 and HEV-4 strains were found to be prevalent in the domestic pigs in China (subtypes 3b, 3d, and 4a-4i) (Liu et al, 2016), and in wild boars from South Korea (subtypes 3a, 4a, and 4d) with 1.29% samples as positive (24/1859) and from Japan (subtypes 3a, 3b, 3e, 4c, 4g, 4i, and 5) with 3.9% as positive (74/1880) (Choe et al, 2020;Takahashi et al, 2020).…”

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Genetic characterization of hepatitis E virus from wild boar in China

Gong

Sun

et al. 2022

Transbounding Emerging Dis

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Hepatitis E virus (HEV), the causative agent of hepatitis E (HE), is classified into four major genotypes (1–4), with wild boar being the main natural reservoir for genotypes 3 and 4. However, little is known about the prevalence of HEV infection in wild boars in China. In this study, RT‐nested PCR and RT‐quantitative PCR were used to detect the HEV RNA in tissue samples taken from 331 free‐ranging wild boars collected between 2018 and 2020 from 24 regions across China, and the partial ORF2 genes or complete genomes of the positive samples were sequenced. Furthermore, antibodies against HEV in 216 serum samples from wild boars were tested by ELISA. As a result, HEV RNA was detected in nine out of 331 liver samples of wild boars (2.72%), which were distributed in eight regions. Genetic and evolutionary analysis of partial ORF2 sequences indicated that the HEV strains identified in this study share 83.9%–100% nucleotide sequence identity and belong to subtypes 4d (n = 6), 4g (n = 2), and 4h (n = 1), and similar phylogeny was obtained using the complete genome sequences of seven wild boar HEV strains. Additionally, the HEV viral loads were higher in the liver than in other tissues and blood. Moreover, 61 out of 216 sera (28.2%) from wild boars tested positive for anti‐HEV antibodies. To our knowledge, this is the first study to report the epidemiological situations of HEV infections in free‐ranging wild boars in China, and the obtained data are valuable for prevention and control of HE.

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Section: Figurementioning

confidence: 99%

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confidence: 99%

Genetic characterization of hepatitis E virus from wild boar in China

Gong

Sun

et al. 2022

Transbounding Emerging Dis

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“…Finally, genotypes 5 and 6 exhibit very limited circulation and have only been identified in Japanese wild boar [ 26 , 27 ]. The lack of these genotypes in domestic pig strongly suggests limited sympatric contact between the two species.…”

Section: Discussionmentioning

confidence: 99%

Global molecular diversity of Hepatitis E virus in wild boar and domestic pig

et al. 2021

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Our study aim was to describe and characterize the global Hepatitis E virus (HEV) molecular and genotype geographical distribution in domestic pig and wild boar, which could facilitate the traceability of human cases. We performed a systematic sequence search for HEVs identified in domestic pig and wild boar from the available data in GenBank. Only sequences with lengths greater than 300 nt were included. For all sequences, the sequence length, host (i.e., domestic pig or wild boar), country of origin, and HEV genotype/subtype were recorded. Genotypes were assigned by the HEVnet typing tool. The genotype distributions were described by country and host. In countries with sequences available for both species, the genotype coincidences between both animal populations were analyzed. A total of 1404 viral sequences were included: 32.6% from wild boar and 67.4% from domestic pig. Most sequences were consistent with HEV genotype 3 ( n = 1165). Genotype 4 was represented by 193 sequences, while genotypes 5 and 6 were represented by only 6 sequences. Sequences were identified in 39 countries, which included all continents except Antarctica. The genotypes with a wide distribution were 3a and 3f. Twenty-five countries had sequences that were found only in domestic pig, three countries only in wild boar, and 11 countries had sequences in both populations. In all countries with available sequences in both populations, the same viral genotype was identified. Our study shows that the number of swine HEV sequences is small, which limits direct comparisons with the sequences identified in humans. The global distribution of genotype 3, together with the wide distribution of genotype 4 in Asia, strongly limits the interpretation of the molecular analysis in the absence of an epidemiological survey of the cases. Increased HEV sequencing in swine should be a priority.

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“…Viremia during infection due to HEV persist for approximately one month after the symptoms appear in healthy individuals; viral RNA in feces has been detected in studies with patients since the first week after the start of the disease up to 28 days later and in serum from the same patients, since the first until the sixth week. Immunoglobulin IgM anti-HEV was detected on the first week after the symptoms appeared and diminished during the following six weeks 46 .…”

Section: Immune Responsementioning

confidence: 99%

Hepatitis E Virus: A review of the current status and perspectives

González

Sanabria

Castaño-Osorio

2021

Infect

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Hepatitis E virus produces approximately 20-million infections per year; symptomatic cases are over 3-million and deaths are approximately 60,000. Generally, it is self-limited; however, it can cause up to 30% mortality in pregnant women and can be chronic in immunosuppressed people. The transmission path of the Hepatitis E virus is principally fecal-oral, especially in developing countries; in industrialized countries, it is transmitted as a zoonosis, through organ transplants or blood transfusions. The vaccine developed is only licensed in China. Currently, no treatment is available for the HEV infection and work is underway in identifying the viral cycle and the immune response. This article sought to offer a review of the theme on the hepatitis E virus, from the last six years, to describe current general aspects of the Hepatitis E virus, genome, ways of transmission and contribute to its visibility for its prevention and control.

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Prevalence and genotype/subtype distribution of hepatitis E virus (HEV) among wild boars in Japan: Identification of a genotype 5 HEV strain

Cited by 28 publications

References 63 publications

Genetic characterization of hepatitis E virus from wild boar in China

Genetic characterization of hepatitis E virus from wild boar in China

Global molecular diversity of Hepatitis E virus in wild boar and domestic pig

Hepatitis E Virus: A review of the current status and perspectives

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