Prevalence of Hepatitis E Virus (HEV) Infection in Wild Boars and Deer and Genetic Identification of a Genotype 3 HEV from a Boar in Japan

Infection with hepatitis E virus (HEV) can cause acute and chronic hepatitis in humans. The HEV genotype 3 can be zoonotically transmitted from animals to humans, with wild boars representing an important reservoir species. Cell culture isolation of HEV is generally difficult and mainly described for human isolates so far. Here, five sera and five liver samples from HEV-RNA-positive wild boar samples were inoculated onto PLC/PRF/5 cells, incubated for 3 months and thereafter passaged for additional 6 weeks. As demonstrated by RT-qPCR, immunofluorescence and immune electron microscopy, virus was successfully isolated from two liver samples, which originally contained high HEV genome copy numbers. Both isolates showed slower growth than the culture-adapted HEV strain 47832c. In contrast to this strain, the isolated strains had no insertions in their hypervariable genome region. Next generation sequencing using an HEV sequence-enriched library enabled full genome sequencing. Strain Wb108/17 belongs to subtype 3f and strain Wb257/17 to a tentative novel subtype recently described in Italian wild boars. The results indicate that HEV can be successfully isolated in cell culture from wild boar samples containing high HEV genome copy numbers. The isolates may be used further to study the zoonotic potential of wild boar-derived HEV subtypes.

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Geographical restriction of Hepatitis E virus circulation in wild boars (Sus scrofa) in Emilia-Romagna region, Northern Italy

Italian Journal of Food Safety ◽

10.4081/ijfs.2020.8463 ◽

2020 ◽

Vol 9 (1) ◽

Author(s):

Silvia Bonardi ◽

Virginia Filipello ◽

Enrico Pavoni ◽

Valentina Carta ◽

Luca Bolzoni ◽

...

Keyword(s):

Wild Boar ◽

Cervus Elaphus ◽

Hepatitis E Virus ◽

Red Deer ◽

Hepatitis E ◽

Northern Italy ◽

Genotype 3 ◽

Hunting Season ◽

Wild Boars ◽

Emilia Romagna Region

Hepatitis E virus (HEV) is a singlestrand RNA virus that causes an acute viral hepatitis in humans. Among its eight recognized genotypes, HEV-3 and HEV-4 are zoonotic, infecting humans, pigs and wild boars. Recently, HEV-3 has been also detected in red deer, which represents another reservoir of HEV. Consumption of raw pork products (mainly liver sausages), undercooked wild boar meat, raw wild boar liver and deer meat has been responsible for foodborne HEV human worldwide. From November 2018 to March 2019, liver samples collected from 97 wild boars hunted in Emilia-Romagna region (Northern Italy) were tested for HEV RNA. The hunting area included two territories for an extension of 33 km2, named A (about 13 km2, natural park, deciduous wood) and B (about 20 km2, cultivated fields in proximity of a river) areas. Distance between the two areas ranged between 8 to 10 km. A total of 73 wild boars were hunted in area A, and 24 in area B. HEV RNA was detected by Realtime RT–PCR in 23/73 liver samples of wild boars living in area A only (31.5% - 95% CI: 22.0-42.8%). The HEV sequences (n=13) clustered within genotype 3. The majority of positives belonged to animals < 12 months (12/25; 48%), followed by subadults (13-24 months) (7/16; 43.8%) and adults (4/32; 12.5%). This difference was found to be statistically significant (p=0.0024). In absence of pig farms, the restriction of HEV-positive animals to a well-defined territory of 13 km2 (Boschi di Carrega Regional Park) could hypothetically be related to the presence of red deer (Cervus elaphus), which lived in area A at the beginning of the hunting season. Further studies are needed to confirm or deny our hypothesis.

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Analysis of the full-length genome of hepatitis E virus isolates obtained from wild boars in Japan

Journal of General Virology ◽

10.1099/vir.0.81394-0 ◽

2005 ◽

Vol 86 (12) ◽

pp. 3321-3326 ◽

Cited By ~ 40

Author(s):

Tsutomu Nishizawa ◽

Masaharu Takahashi ◽

Kazunori Endo ◽

Shinji Fujiwara ◽

Nobuo Sakuma ◽

...

Keyword(s):

Hepatitis E Virus ◽

Hepatitis E ◽

Full Length ◽

Partial Sequence ◽

Genotype 3 ◽

Entire Genome ◽

Wild Boars ◽

Full Length Sequence ◽

Full Length Genome ◽

Virus Isolates

Two (2·3 %) of 87 wild-caught boars in Japan had detectable hepatitis E virus (HEV) RNA. The two boar HEV isolates (wbJTS1 and wbJYG1) obtained in the present study and a previously reported isolate (wbJSG1) whose partial sequence had been determined were sequenced over the entire genome. The wbJSG1, wbJTS1 and wbJYG1 isolates comprised 7225 or 7226 nt, excluding the poly(A) tail, and segregated into genotype 3. They differed by 8·5–11·2 % from each other and by 8·6–18·4 % from 17 reported genotype 3 HEV isolates, including one boar isolate, in the full-length sequence. When compared with 191 reported genotype 3 HEV isolates whose partial sequences were known, these three boar isolates were closer to Japanese isolates than to isolates of non-Japanese origin (89·2±2·6 vs 85·9±2·2 %; P<0·0001). A proportion of wild boars in Japan are infected with markedly heterogeneous HEV strains that are indigenous to Japan and may serve as reservoirs of HEV.

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THE SEROPREVALENCE OF HEPATITIS E VIRUS INFECTION IN WILD BOARS IN SERBIA

Archives of Veterinary Medicine ◽

10.46784/e-avm.v4i1.175 ◽

2011 ◽

Vol 4 (1) ◽

pp. 19-29

Author(s):

Diana Lupulović ◽

Tamaš Petrović ◽

Sava Lazić ◽

Jasna Prodanov Radulović ◽

Radoslav Došen ◽

...

Keyword(s):

Hepatitis E Virus ◽

Hepatitis E ◽

Oral Route ◽

Genotype 3 ◽

Species Barrier ◽

Serum Samples ◽

Serological Tests ◽

Wild Boars ◽

Infected People ◽

Contaminated Food

Hepatitis E (HEV) belongs to one of fi ve so far described types of viral hepatitis caused by human agents (hepatitis A, B, C, D and E). The disease is characterized by clinical and epidemiological signs of acute hepatitis and is transmitted primarily by fecal-oral route via contaminated food and water. The infection is mainly detected in the developing countries of the Middle East, Asia and Africa, especially in countries with poor sanitary conditions of life. HEV infection in pigs was fi rst recorded in 1990. Numerous studies that followed proved that HEV can skip species barrier and can be transmitted from pigs to humans. HEV has been demonstrated as a new zoonotic agent. Hepatitis E virus has infected people in Japan who consumed insuffi ciently cooked meat of deer, pig liver and meat of wild boar. In humans four genotypes have been determined: I, II, III and IV, while so far tested swine isolates belong to genotypes III and IV. It is also important to note that the swine HEV isolates from one geographical region are genetically closer to human isolates from the same area than to the other isolates from pigs in the world. Th e aim of this paper is to show whether and how much HEV infection is present in the population of wild boars in Serbia, which represent a reservoir of this disease caused by a signifi cant zoonotic agent. Preliminary serological tests included the examination of 92 blood serum samples of wild boars. In 32 animals, or 34.78%, the presence of specifi c antibodies against HEV genotype was detected. Th e blood samples were collected during 2009, 2010 and 2011 from 15 hunting sites in Serbia. Laboratory testing was performed by non-commercial ELISA (in-house ELISA), where the used antigen was recombinant capsid protein-HEV genotype 3 ΔORF 2, which was obtained by laboratory cloning procedure. The test results showed that the hepatitis E virus is present in wild boars in Vojvodina, that are a potential source of this infection, as well as for many other infections of diferrent etiology.

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Preliminary study on the detection of hepatitis E virus (HEV) antibodies in pigs and wild boars in Poland

Journal of Veterinary Research ◽

10.1515/jvetres-2016-0057 ◽

2016 ◽

Vol 60 (4) ◽

pp. 385-389 ◽

Cited By ~ 2

Author(s):

Marcin Weiner ◽

Małgorzata Tokarska-Rodak ◽

Dorota Plewik ◽

Anna Pańczuk ◽

Adam Szepeluk ◽

...

Keyword(s):

Hepatitis E Virus ◽

Meat Products ◽

Hepatitis E ◽

Developed Countries ◽

Igg Antibodies ◽

Genotype 3 ◽

Pork Production ◽

Wild Boars ◽

Preliminary Study ◽

Positive Results

Abstract Introduction: Although HEV infection in pigs does not pose a major economic risk to pork production, the risk of zoonotic transmission to humans is an important aspect of public health. HEV genotype 3 infections were reported in developed countries in individuals who had consumed raw meat or meat products from deer, wild boars, or pigs. The aim of the study was the analysis of the occurrence of HEV-specific antibodies among wild boars and domestic pigs in Poland. Material and Methods: A total of 290 samples from wild boars and 143 samples from pigs were tested. The antibodies were tested by ELISA. Results: The presence of anti-HEV IgG was demonstrated in 44.1% of pigs and 31.0% of wild boars. Anti-HEV IgG antibodies were detected in 1.4% of samples from pigs and in 2.1% of samples from wild boars at borderline level. The statistical analysis shows significant differences in the positive results for anti-HEV IgG between the groups of pigs and wild boars (P = 0.0263). Conclusion: Regular surveillance of the occurrence of HEV in swine and wild boars should be performed in the future.

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Detection and genetic characterization of hepatitis E virus (HEV) genotype 3 subtype c in wild boars in Italy

Archives of Virology ◽

10.1007/s00705-016-2964-y ◽

2016 ◽

Vol 161 (10) ◽

pp. 2829-2834 ◽

Cited By ~ 15

Author(s):

Federica Di Profio ◽

Irene Melegari ◽

Vittorio Sarchese ◽

Serena Robetto ◽

Giuseppe Marruchella ◽

...

Keyword(s):

Hepatitis E Virus ◽

Genetic Characterization ◽

Hepatitis E ◽

Subtype C ◽

Genotype 3 ◽

Wild Boars

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Advances in Hepatitis E Virus Biology and Pathogenesis

Viruses ◽

10.3390/v13020267 ◽

2021 ◽

Vol 13 (2) ◽

pp. 267

Author(s):

Shaoli Lin ◽

Yan-Jin Zhang

Keyword(s):

Pregnant Women ◽

Hepatitis E Virus ◽

Case Fatality ◽

Hepatitis E ◽

Host Cells ◽

High Rate ◽

Rapid Progression ◽

Genotype 1 ◽

Genotype 3 ◽

Zoonotic Infections

Hepatitis E virus (HEV) is one of the causative agents for liver inflammation across the world. HEV is a positive-sense single-stranded RNA virus. Human HEV strains mainly belong to four major genotypes in the genus Orthohepevirus A, family Hepeviridae. Among the four genotypes, genotype 1 and 2 are obligate human pathogens, and genotype 3 and 4 cause zoonotic infections. HEV infection with genotype 1 and 2 mainly presents as acute and self-limiting hepatitis in young adults. However, HEV infection of pregnant women with genotype 1 strains can be exacerbated to fulminant hepatitis, resulting in a high rate of case fatality. As pregnant women maintain the balance of maternal-fetal tolerance and effective immunity against invading pathogens, HEV infection with genotype 1 might dysregulate the balance and cause the adverse outcome. Furthermore, HEV infection with genotype 3 can be chronic in immunocompromised patients, with rapid progression, which has been a challenge since it was reported years ago. The virus has a complex interaction with the host cells in downregulating antiviral factors and recruiting elements to generate a conducive environment of replication. The virus-cell interactions at an early stage might determine the consequence of the infection. In this review, advances in HEV virology, viral life cycle, viral interference with the immune response, and the pathogenesis in pregnant women are discussed, and perspectives on these aspects are presented.

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Infection dynamics and persistence of hepatitis E virus on pig farms – a review

Porcine Health Management ◽

10.1186/s40813-021-00189-z ◽

2021 ◽

Vol 7 (1) ◽

Author(s):

M. Meester ◽

T. J. Tobias ◽

M. Bouwknegt ◽

N. E. Kusters ◽

J. A. Stegeman ◽

...

Keyword(s):

Risk Factors ◽

Hepatitis E Virus ◽

Risk Mitigation ◽

Transmission Rate ◽

Hepatitis E ◽

Main Body ◽

Genotype 3 ◽

Infection Dynamics ◽

Pig Farms ◽

Slaughter Pigs

Abstract Background Hepatitis E virus (HEV) genotype 3 and 4 is a zoonosis that causes hepatitis in humans. Humans can become infected by consumption of pork or contact with pigs. Pigs are the main reservoir of the virus worldwide and the virus is present on most pig farms. Main body Though HEV is present on most farms, the proportion of infected pigs at slaughter and thus the level of exposure to consumers differs between farms and countries. Understanding the cause of that difference is necessary to install effective measures to lower HEV in pigs at slaughter. Here, HEV studies are reviewed that include infection dynamics of HEV in pigs and on farms, risk factors for HEV farm prevalence, and that describe mechanisms and sources that could generate persistence on farms. Most pigs become infected after maternal immunity has waned, at the end of the nursing or beginning of the fattening phase. Risk factors increasing the likelihood of a high farm prevalence or proportion of actively infected slaughter pigs comprise of factors such as farm demographics, internal and external biosecurity and immunomodulating coinfections. On-farm persistence of HEV is plausible, because of a high transmission rate and a constant influx of susceptible pigs. Environmental sources of HEV that enhance persistence are contaminated manure storages, water and fomites. Conclusion As HEV is persistently present on most pig farms, current risk mitigation should focus on lowering transmission within farms, especially between farm compartments. Yet, one should be aware of the paradox of increasing the proportion of actively infected pigs at slaughter by reducing transmission insufficiently. Vaccination of pigs may aid HEV control in the future.

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Hepatitis E Virus Occurrence in Pigs Slaughtered in Italy

Animals ◽

10.3390/ani11020277 ◽

2021 ◽

Vol 11 (2) ◽

pp. 277

Author(s):

Eleonora Chelli ◽

Elisabetta Suffredini ◽

Paola De Santis ◽

Dario De Medici ◽

Santina Di Bella ◽

...

Keyword(s):

Hepatitis E Virus ◽

Phylogenetic Analyses ◽

Hepatitis E ◽

Rt Pcr ◽

High Seroprevalence ◽

Genotype 3 ◽

Sporadic Cases ◽

Wild Boar Meat ◽

Small Clusters ◽

Frequent Exposure

In Europe, foodborne transmission has been clearly associated to sporadic cases and small clusters of hepatitis E in humans linked to the consumption of contaminated pig liver sausages, raw venison, or undercooked wild boar meat. In Europe, zoonotic HEV-genotype 3 strains are widespread in pig farms but little information is available on the prevalence of HEV positive pigs at slaughterhouse. In the present study, the prevalence of HEV-RNA positive pigs was assessed on 585 animals from 4 abattoirs located across Italy. Twenty-one pigs (3.6%) tested positive for HEV in either feces or liver by real-time RT-PCR. In these 21 pigs, eight diaphragm muscles resulted positive for HEV-RNA. Among animals collected in one abattoir, 4 out of 91 plasma tested positive for HEV-RNA. ELISA tests for the detection of total antibodies against HEV showed a high seroprevalence (76.8%), confirming the frequent exposure of pigs to the virus. The phylogenetic analyses conducted on sequences of both ORF1 and ORF2 fragments, shows the circulation of HEV-3c and of a novel unclassified subtype. This study provides information on HEV occurrence in pigs at the slaughterhouse, confirming that muscles are rarely contaminated by HEV-RNA compared to liver, which is the most frequently positive for HEV.

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Hepatitis E Virus in Croatia in the “One-Health” Context

Pathogens ◽

10.3390/pathogens10060699 ◽

2021 ◽

Vol 10 (6) ◽

pp. 699

Author(s):

Anna Mrzljak ◽

Lorena Jemersic ◽

Vladimir Savic ◽

Ivan Balen ◽

Maja Ilic ◽

...

Keyword(s):

Hepatitis E Virus ◽

Current Knowledge ◽

Hepatitis E ◽

Human Case ◽

Interspecies Transmission ◽

Genotype 3 ◽

Chronic Patients ◽

Indirect Contact ◽

The One ◽

Foodborne Infection

Hepatitis E virus (HEV) is the most common cause of viral hepatitis globally. The first human case of autochthonous HEV infection in Croatia was reported in 2012, with the undefined zoonotic transmission of HEV genotype 3. This narrative review comprehensively addresses the current knowledge on the HEV epidemiology in humans and animals in Croatia. Published studies showed the presence of HEV antibodies in different population groups, such as chronic patients, healthcare professionals, voluntary blood donors and professionally exposed and pregnant women. The highest seroprevalence in humans was found in patients on hemodialysis in a study conducted in 2018 (27.9%). Apart from humans, different studies have confirmed the infection in pigs, wild boars and a mouse, indicating the interspecies transmission of HEV due to direct or indirect contact or as a foodborne infection. Continued periodical surveys in humans and animals are needed to identify the possible changes in the epidemiology of HEV infections.

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