Bats worldwide carry hepatitis E virus-related viruses that form a putative novel genus within the family Hepeviridae. J Virol. 2012;86:9134-9147. [PMID: 22696648 DOI: 10.1128/jvi.00800-12]

Occurrence and Molecular Characterization of Human Astrovirus and Hepatitis A Virus in Bivalve Mollusks Marketed in Tourist Cities in Rio de Janeiro, Brazil

This study investigated the prevalence and genetic diversity of human astrovirus (HAstV), hepatitis A virus (HAV), and hepatitis E virus (HEV) in bivalve mollusks (mussels and oysters) marketed in three tourist cities in the State of Rio de Janeiro, Brazil, from January to December 2022. One hundred and thirty-four samples were processed according to the ISO 15216-1:2017 (Microbiology of food a chain-horizontal method for determination of hepatitis A virus and norovirus in food using real-time RTPCR-Part 1: method for quantification, vol 2017. International Organization for Standardization, Geneva, pp 1-48, 2017), and viral screening was performed by the TaqMan real-time RT-qPCR. HAstV RNA was detected in 13.9% (10/72) of the oyster samples and 14.5% (9/62) of the mussel samples. HAV RNA was detected in 8.1% (5/62) of the mussels, while HEV RNA was not detected in any of the analyzed bivalves. The molecular characterization revealed that HAstV strains detected in live oysters belonged to both classical (HAstV-1) and non-classical (MLB-1) genotypes. The HAV-IA genotype was detected in mussel samples and segregated into two subclusters. This study reports the presence of HAstV and HAV in oysters and mussels marketed in Brazil for the first time. The findings indicate local water contamination in the bivalve sampling areas, highlighting the importance of environmental monitoring and surveillance improvements, particularly in shellfish production areas.

Genetic Diversity and Molecular Evolution of Hepatitis E Virus Within the Genus Chirohepevirus in Bats

Hepatitis E virus (HEV) is a major zoonotic pathogen causing hepatitis E, with strains identified in various animal species, including pigs, wild boar, rabbits, deer, camels, and rats. These variants are capable of crossing species barriers and infecting humans. HEV belongs to the family Hepeviridae, which has recently divided into two subfamilies: Orthohepevirinae and Parahepevirinae, and five genera: Paslahepevirus, Avihepevirus, Rocahepevirus, Chirohepevirus, and Piscihepevirus. Recent advances in high-throughput sequencing, particularly of bat viromes, have revealed numerous HEV-related viruses, raising concerns about their zoonotic potential. Bat-derived HEVs have been classified into the genus Chirohepevirus, which includes three distinct species. In this study, we analyzed 64 chirohepevirus sequences from 22 bat species across six bat families collected from nine countries. Twelve sequences represent complete or nearly complete viral genomes (>6410 nucleotides) containing the characteristic three HEV open reading frames (ORFs). These strains exhibited high sequence divergence (>25%) within their respective host genera or species. Phylogenetic analyses with maximum likelihood methods identified at least seven distinct subclades within Chirohepevirus, each potentially representing an independent species. Additionally, the close phylogenetic relationship between chirohepevirus strains and their bat hosts indicates a pattern of virus-host co-speciation. Our findings expand the known diversity within the family Hepeviridae and provide new insights into the evolution of bat-associated HEV. Continued surveillance of chirohepevirus will be essential for understanding its potential for zoonotic transmission and public health risks.

Rat hepatitis E virus as an aetiological agent of acute hepatitis of unknown origin

BACKGROUND AND AIM

Rat hepatitis E virus (ratHEV) is an emerging cause of acute hepatitis worldwide. The limited number of ratHEV cases may be associated with the lack of a proper molecular diagnosis method; thus, the clinical impact and breadth of ratHEV as a cause of acute hepatitis remain uncertain.

METHODS

The study was carried out in four phases. I) Identification: Molecular assays were identified through a literature search. II) Testing: The methods were evaluated in a rodent testing cohort, and the most suitable molecular diagnosis algorithm was established. III) Derivation: The established algorithm was tested in a larger rodent cohort. IV) Clinical validation: The algorithm was used in a cohort of individuals suffering from acute hepatitis of unknown aetiology, thus establishing the frequency of ratHEV as an aetiological agent of acute hepatitis and its clinical impact.

RESULTS

We detected differences in the frequency of positive results among the assays evaluated. After comparing all available molecular methods, we established a molecular diagnostic algorithm, which revealed that 17.5% of the 103 rodents in the validation cohort were infected with ratHEV. In the clinical validation cohort, of 562 patients with acute hepatitis of unknown origin, 8 cases of ratHEV infection were identified during the three years of the study, representing a frequency of 1.4%. One (37.5%) case had severe acute hepatitis; four (50.0%) patients required hospitalization, one of whom (12.5%) died. The strains detected in these patients revealed a close phylogenetic relationship with those found in rats in Spain.

CONCLUSIONS

Our study demonstrated that ratHEV is an emerging and underdiagnosed cause of acute hepatitis. The results provide evidence that ratHEV should be monitored and included in the differential diagnosis of acute hepatitis.

CLINICAL TRIAL NUMBER

ClinicalTrials.gov Identifier: NCT05062967 IMPACT AND IMPLICATIONS: While rat hepatitis E virus (ratHEV) is a newly emerging zoonotic virus worldwide, the results of the present study indicate that the molecular diagnosis methods for this virus may be inappropriate. After establishing a proper molecular diagnostic algorithm using available assays, we demonstrated that ratHEV is an emerging and underdiagnosed aetiological agent of acute hepatitis of unknown origin. The results also expand the knowledge of the diversity of ratHEV strains capable of infecting humans in Europe. These findings strongly suggest that ratHEV should be monitored and included in the differential diagnosis of acute hepatitis.

Identification of novel rodent and shrew orthohepeviruses sheds light on hepatitis E virus evolution

The family Hepeviridae has seen an explosive expansion in its host range in recent years, yet the evolutionary trajectory of this zoonotic pathogen remains largely unknown. The emergence of rat hepatitis E virus (HEV) has introduced a new public health threat due to its potential for zoonotic transmission. This study investigated 2 464 wild small mammals spanning four animal orders, eight families, 21 genera, and 37 species in Yunnan Province, China. Using broadly reactive reverse transcription-polymerase chain reaction (RT-PCR), we systematically screened the presence and prevalence of Orthohepevirus and identified 192 positive specimens from 10 species, corresponding to an overall detection rate of 7.79%. Next-generation sequencing enabled the recovery of 24 full-length genomic sequences from eight host species, including Bandicota bengalensis, Eothenomys eleusis, and Episoriculus caudatus, representing newly reported host species for Orthohepevirus strains. Phylogenetic and sequence analyses revealed extensive genetic diversity within orthohepeviruses infecting rodents and shrews. Notably, among the identified strains, 20 were classified as Rocahepevirus ratti C1, two as C3, and one as Rocahepevirus eothenomi, while the remaining strain exhibited significant divergence, precluding classification. Evolutionary analyses highlighted close associations between orthohepeviruses and their respective host taxa, with distinct phylogenetic clustering patterns observed across different host orders. These findings emphasize the critical roles of co-speciation and cross-species transmission in shaping the evolutionary trajectories of the genera Paslahepevirus and Rocahepevirus.

Detection of Rocahepevirus ratti in Bivalve Mollusks from São Luís Island, Maranhão, Brazil: A Potential Transmission Route of an Emerging Zoonotic Pathogen?

The attempt to investigate hepatitis E virus (HEV) contamination in naturally growing mangrove bivalve mollusks captured for local sale in a touristic area of Maranhão state in Brazil revealed the detection of rat hepatitis E virus (ratHEV). Using international standard protocols for processing and nucleic acid extraction, we analyzed 89 bivalve samples (Mytella falcata and Crassostrea rhizophorae) with two broadly reactive assays: heminested pan-Hepeviridae (ORF-1) and probe-based HEV-1 to HEV-4 (ORF-2/ORF-3). Heminested reactions presented 2 (2.2%) amplifications of the expected size. Nucleotide identities ranged from 86.6 to 89.0% with ratHEV isolates from wild rats, pigs, one human case and sewage reported in different countries. Regarding the phylogenetic tree, the sequences grouped with genotype HEV-C1. This first report of ratHEV detection in bivalve mollusks may be a starting point for further research on virus variability, distribution, host range and especially the possible role of contaminated shellfish as a vehicle for ratHEV transmission.

Surveillance of Emerging Rodent-Borne Pathogens in Wastewater in Taiwan: A One Health Approach

Leptospirosis and hantavirus syndrome are two major rodent-borne diseases in Taiwan. Rocahepevirus ratii (RHEV), a virus closely related to hepatitis E virus (HEV, Paslahepevirus balayani), is emerging and has been reported to cause hepatitis in humans. We employed wastewater-based epidemiology to actively monitor rodent-borne pathogens, and the correlations with human cases were evaluated. Wastewater was collected using grab sampling at 11 sites along a sewer system including influents and effluents at a wastewater treatment plant in Tamsui, New Taipei City, Taiwan, monthly during June 2023 to May 2024. The presence of pathogens was examined by reverse transcription-polymerase chain reaction (RT-PCR). The result showed an overall positivity rate of 38.2% (50/131). Leptospira was detected most often (48/131, 36.6%), and RHEV and hantaviruses were found once each during the study period. Sequencing identified Leptospira interrogans close to isolates from rodents and human cases, while sequences of hantavirus and RHEV were most similar to isolates from rodents. No significant correlation was found with human cases or positive samples for rodent DNA. Here, we present an example of a One Health approach applying wastewater to environmental surveillance for the early detection and prevention of emerging diseases.

From discovery to treatment: tracing the path of hepatitis E virus

The hepatitis E virus (HEV) is a major cause of acute viral hepatitis worldwide. HEV is classified into eight genotypes, labeled HEV-1 through HEV-8. Genotypes 1 and 2 exclusively infect humans, while genotypes 3, 4, and 7 can infect both humans and animals. In contrast, genotypes 5, 6, and 8 are restricted to infecting animals. While most individuals with a strong immune system experience a self-limiting infection, those who are immunosuppressed may develop chronic hepatitis. Pregnant women are particularly vulnerable to severe illness and mortality due to HEV infection. In addition to liver-related complications, HEV can also cause extrahepatic manifestations, including neurological disorders. The immune response is vital in determining the outcome of HEV infection. Deficiencies in T cells, NK cells, and antibody responses are linked to poor prognosis. Interestingly, HEV itself contains microRNAs that regulate its replication and modify the host's antiviral response. Diagnosis of HEV infection involves the detection of HEV RNA and anti-HEV IgM/IgG antibodies. Supportive care is the mainstay of treatment for acute infection, while chronic HEV infection may be cleared with the use of ribavirin and pegylated interferon. Prevention remains the best approach against HEV, focusing on sanitation infrastructure improvements and vaccination, with one vaccine already licensed in China. This comprehensive review provides insights into the spread, genotypes, prevalence, and clinical effects of HEV. Furthermore, it emphasizes the need for further research and attention to HEV, particularly in cases of acute hepatitis, especially among solid-organ transplant recipients.

Seroprevalence and Phylogenetic Characterization of Hepatitis E Virus (Paslahepevirus balayani) in Guinean Pig Population

Background: Hepatitis E virus (HEV) is transmitted by the fecal route, usually through contaminated water in humans and/or infected animals, especially pigs. The objective of this study was to evaluate the level of anti-HEV antibodies in a panel of pig sera and to identify HEV in pig feces in farms. Methodology: The presence of HEV antibodies was tested by an in-house ELISA and a commercial ELISA IDvet. HEV genome was assessed by nested RT-PCR, and then, genotype was identified by sequencing (MinION Nanopore technology). Results: In 2017-2019, the 43% seroprevalence found in Forest Guinea was significantly higher than the 7% found in the Lower region (p < 0.01). Presence of HEV genotype 3c was demonstrated during a secondary study in the Lower region (Conakry) in 2022. Conclusion: The presence of HEV-3c in pigs calls for an evaluation of seroprevalence in human populations and for a HEV genotype human circulation check. Contribution Heading: This study is the first report, to our knowledge, of seroprevalence and characterization of HEV infection in pigs in Guinea.

Investigating the Hepatitis E Virus (HEV) Diversity in Rat Reservoirs from Northern Italy

Hepatitis E virus belonging to the Rocahepevirus ratti species, genotype HEV-C1, has been extensively reported in rats in Europe, Asia and North America. Recently, human cases of hepatitis associated with HEV-C1 infection have been reported, but the zoonotic nature of rat-HEV remains controversial. The transmission route of rat-HEV is unidentified and requires further investigation. The HEV strains of the Paslahepevirus balayani species, belonging to the same Hepeviridae family, and including the zoonotic genotype HEV-3 usually found in pigs, have also sporadically been identified in rats. We sampled 115 rats (liver, lung, feces) between 2020 and 2023 in Northeast Italy and the HEV detection was carried out by using Reverse Transcription PCR. HEV RNA was detected in 3/115 (2.6%) rats who tested positive for HEV-C1 strains in paired lung, intestinal contents and liver samples. Overall, none tested positive for the Paslahepevirus balayani strains. In conclusion, our results confirm the presence of HEV-rat in Italy with a prevalence similar to previous studies but show that there is a wide heterogeneity of strains in circulation. The detection of HEV-C1 genotype of Rocahepevirus ratti species in some human cases of acute hepatitis suggests that HEV-C1 may be an underestimated source of human infections. This finding, with the geographically widespread detection of HEV-C1 in rats, raises questions about the role of rats as hosts for both HEV-C1 and HEV-3 and the possibility of zoonotic transmission.

Brno loanvirus (BRNV) in bats inhabiting the urban area of Brno, Czech Republic

Bats are known reservoirs of various emerging pathogens, and have recently been found to host a novel hantavirus, named Brno loanvirus (BRNV), from the Mammantavirinae subfamily (family Hantaviridae, order Bunyavirales). Here we report BRNV detection in bats from the urban area of Brno, Czech Republic in March 2022. Specifically, we uncovered a high prevalence of BRNV (8.8%, 5/57) among hibernating bats (Nyctalus noctula) in urban area, which poses a risk of human exposure. The positive bats included adult females (3/9 positive), a juvenile female (1/32 positive), and an adult male (1/6 positive). All 10 juvenile males were negative. We used RT-qPCR to quantify the BRNV RNA levels in various bat organs, which yielded positive results for viral RNA in organs, including the kidneys, heart, spleen, brain, liver, lung, and gut, and in body cavity fluid. Among all tested organs, the liver showed the highest levels of viral RNA in 4 out of 5 animals examined (average Ct value of 20.8 ± 7.4).

Detection of anti-HEV antibodies but no molecular positivity in dogs in the Campania region, southern Italy

Paslahepevirus balayani genotypes 3 and 4 (HEV-3 and 4) have zoonotic potential and can be transmitted to humans and animals through the consumption of contaminated raw or undercooked meat. Although it has been demonstrated that dogs are susceptible to the infection and produce specific antibodies, the epidemiological role of this species is not yet well defined. This study aimed to evaluate the circulation of HEV at the serological and molecular level in the dog population of the Campania region, southern Italy. A total of 231 dogs were sampled, divided according to several variables (sex, age, origin, lifestyle, location, size, and breed), and tested for the presence of HEV antibodies using a commercial multi-species ELISA. A total of 197 blood samples and 170 stool samples were tested with two specific PCRs in order to detect viral RNA. A total of 19 out samples of 231 were seropositive, obtaining an exposure (8.2%) similar to that observed in other European countries. The univariate and multivariate analysis revealed a wide exposure to stray dogs and animals from the province of Salerno. All samples tested with molecular methods were negative. Defining the role of domestic carnivores continues to be a "one health" challenge, although it appears that they do not eliminate the virus and therefore do not pose a danger to humans. In the absence of other evidence, it is advisable to continue to carry out surveillance also for domestic animals, which, due to ethological characteristics or their position in the food chain, could be predisposed to being exposed to HEV.

Evaluation of hepatitis E virus RNA persistence in experimentally contaminated cured pork liver sausages

Hepatitis E is a disease sustained by RNA viruses, which have four different genotypes, all of which are responsible for acute forms of hepatitis. Genotypes 1 and 2 infect only humans, causing epidemics mainly transmitted by contaminated water, while geno-types 3 and 4 are zoonotic, and the infection is linked to the consumption of raw or undercooked meat or meat products. Hepatitis E virus (HEV) genotypes 3 and 4 have been detected in domestic Suidae, considered the asymptomatic reservoir of HEV, and in wild animals such as wild boar and deer. Despite scientific studies that have highlighted the presence of HEV in cured meat products, such as pork liver sausages, the viral persistence in the different production steps of curing has not been evaluated. Therefore, this study aimed to evaluate the persistence of HEV genotype 3 during the different curing and storage times of experimentally contaminated pork liver sausages using biomolecular methods. The sausages tested positive at all curing and storage times. This study confirms the potential risk attributed to pork liver sausages in HEV transmission. However, to guarantee an efficient risk assessment, future studies will be performed to correlate the presence of HEV RNA with infectious viral particles.

Animal models of hepatitis E infection: Advances and challenges

Hepatitis E virus (HEV) is one of the leading causes of acute viral hepatitis worldwide. Although most of HEV infections are asymptomatic, some patients will develop the symptoms, especially pregnant women, the elderly, and patients with preexisting liver diseases, who often experience anorexia, nausea, vomiting, malaise, abdominal pain, and jaundice. HEV infection may become chronic in immunosuppressed individuals. In addition, HEV infection can also cause several extrahepatic manifestations. HEV exists in a wide range of hosts in nature and can be transmitted across species. Hence, animals susceptible to HEV can be used as models. The establishment of animal models is of great significance for studying HEV transmission, clinical symptoms, extrahepatic manifestations, and therapeutic strategies, which will help us understand the pathogenesis, prevention, and treatment of hepatitis E. This review summarized the animal models of HEV, including pigs, monkeys, rabbits, mice, rats, and other animals. For each animal species, we provided a concise summary of the HEV genotypes that they can be infected with, the cross-species transmission pathways, as well as their role in studying extrahepatic manifestations, prevention, and treatment of HEV infection. The advantages and disadvantages of these animal models were also emphasized. This review offers new perspectives to enhance the current understanding of the research landscape surrounding HEV animal models.

The molecular epidemiology of hepatitis E virus genotype 3 in Canada

Autochthonous hepatitis E virus (HEV) infection is increasingly reported in industrialized countries and is mostly associated with zoonotic HEV genotype 3 (HEV-3). In this study, we examined the molecular epidemiology of 63 human clinical HEV-3 isolates in Canada between 2014 and 2022. Fifty-five samples were IgM positive, 45 samples were IgG positive and 44 were IgM and IgG positive. The majority of the isolates belong to the subtypes 3a, 3b, and 3j, with high sequence homology to Canadian swine and pork isolates. There were a few isolates that clustered with subtypes 3c, 3e, 3f, 3h, and 3g, and an isolate from chronic infection with a rabbit strain (3ra). Previous studies have demonstrated that the isolates from pork products and swine from Canada belong to subtypes 3a and 3b, therefore, domestic swine HEV is likely responsible for the majority of clinical HEV cases in Canada and further support the hypothesis that swine serve as the main reservoirs for HEV-3 infections. Understanding the associated risk of zoonotic HEV infection requires the establishment of sustainable surveillance strategies at the interface between humans, animals, and the environment within a One-Health framework.

Genomic characterization of Rocahepevirus ratti hepatitis E virus genotype C1 in Yunnan province of China

The Rocahepevirus ratti hepatitis E virus genotype C1 (HEV-C1) has been documented to infect humans. However, the understanding of HEV-C1 remains constrained. This study aims to determine the prevalence and genomic characteristics of HEV-C1 in small animals in Yunnan province of southwestern China. A total of 444 liver tissues were collected from animals covering the orders Rodentia, Soricomorpha, Scandentia and Erinaceomorpha in three regions in Yunnan. Then Paslahepevirus balayani and Rocahepevirus were examined using RT-qPCR. The detection rate of Rocahepevirus was 12.95 % (36/278) in animals of order Rodentia, with 14.77 % (35/237) in Rattus tanezumi and 33.33 % (1/3) in Niviventer fulvescens. No Paslahepevirus balayani was detected. Additionally, two full-length Rocahepevirus sequences (MSE-17 and LHK-54) and thirty-three partial ORF1 sequences were amplified and determined to be HEV-C1. MSE-17 and LHK-54 shared moderate nucleotide identity (78.9 %-80.3 %) with HEV-C1 isolated in rats and humans. The HEV-C1 isolated from Niviventer fulvescens demonstrated a 100 % nucleotide identity with that from Rattus tanezumi. The rat HEV-C1 sequences isolated in our study and other Asian HEV-C1 sequences were phylogenetically distant from those isolated in North America and Europe. Furthermore, the two full-length sequences isolated in our study had less amino acid substitutions in the motifs of RNA-dependent RNA polymerase domain (F204L and L238F), compared with other Asian sequences. In summary, HEV-C1 commonly spreads in rats in Yunnan province of China. Our findings suggest a spatially associated phylogeny, and potential cross-species transmission of HEV-C1.

Genotypic analysis of hepatitis E virus (HEV) from sporadic symptomatic cases in Pakistan

Pakistan is the fifth most populous nation in the world and faces several challenges, including devastating floods, sub-optimal sanitary conditions, clustered accommodations, and unregulated cross-border movements. These drastic population shifts make it vulnerable to the efficient spread of the Hepatitis E virus (HEV). The current study analyzed the genotypic characteristics and variants of the Hepatitis E virus circulating in the population of Pakistan. A total of 75 ELISA-IgM positive samples were collected from three metropolitan cities: Lahore, Peshawar, and Karachi, and subjected to viral RNA extraction. The amplification of the HEV RNA-dependent RNA polymerase (RdRp) region was done using Nested PCR and degenerate primers. Out of the total, 40% of the samples were positive for HEV RNA. Sequencing and phylogenetic analysis identified the new HEV isolates as Subtype 1 g, a subtype within an existing HEV genotype 1. This shift warrants investigation into its impact on clinical manifestation and disease severity. Importantly, this study marks the first HEV subtype analysis in Pakistan, contributing valuable insights into subtype diversity and prevalence in the region.

Surveillance for rat hepatitis E in wastewater networks, Italy

IMPORTANCE

Hepatitis E virus (HEV) infection constitutes a significant health problem worldwide. In recent years, in addition to the zoonotic HEV3 and HEV4, emerging highly divergent hepevirus of rat origin (rat HEV [RHEV]) has been associated with human acute and chronic hepatitis. As environmental surveillance can be a complementary tool to explore emerging viruses of human and rodent origin, we investigated the epidemiology and the genetic variability of RHEV targeting 14 wastewater treatment plants in an Italian geographic area considered a hot spot for HEV infection in humans. Our results revealed that RHEV is a significant component of the wastewater microbiota with viral RNA detected in 43.9% of the specimens tested, adding further evidence to the need to investigate more in depth the real burden of RHEV infections in humans.

Epidemiological survey and risk factors associated with Paslahepevirus balayani in equines in Europe

Paslahepevirus balayani (HEV) is an important emerging zoonotic virus in Europe. Although domestic pigs and wild boar are the main reservoirs of this pathogen, susceptibility to this virus has been confirmed in a growing number of animal species, including equines. However, their role in the epidemiology of this virus remains poorly understood. Our aim was to assess HEV circulation and identify potential risk factors associated with exposure in equid species in different European countries. A total of 596 equines, including 496 horses, 63 donkeys and 37 mules/hinnies bred in four European countries (Spain, Italy, United Kingdom and Ireland) were sampled. Thirty-three animals (5.5%; 95%CI: 3.7-7.4) had anti-HEV antibodies. Seropositivity was found in 4.6% of horses, 11.1% of donkeys and 8.1% of mules/hinnies tested. By country, 6.3%, 5.4%, 5.0% and 4.0% of the equines sampled in Spain, Italy, United Kingdom and Ireland, respectively, were seropositive, respectively. Statistical analysis showed that "species" and "drinking water from ponds and streams" were potential risk factors associated with HEV seropositivity in equines in Europe. HEV RNA was not detected in any (0.0%; 95%CI: 0.0-1.8) of the 202 equines tested. Our results provide evidence of a low, spatially homogeneous and widespread viral circulation that is not equal across species in equid populations in the European countries analyzed and indicate that these species appear to play a limited role in the epidemiology of this virus. Further studies are required to elucidate the differences in seroprevalence between donkeys, mules/hinnies and horses and to determine the risk of zoonotic transmission of this pathogen from equid species.

Co-circulation of Hepatitis E Virus (HEV) Genotype 3 and Moose-HEV-Like Strains in Free-Ranging-Spotted Deer (Axis axis) in Uruguay

Hepatitis E caused by hepatitis E virus (HEV) is considered an emerging foodborne zoonosis in industrialized, non-endemic countries. Domestic pigs and wild boars are considered the main reservoir of HEV. However, HEV can also infect an ever-expanding host range of animals, but they exact role in transmitting the virus to other species or humans is mostly unknown. In this work, we investigated the spread of HEV in free-living and captive spotted deer (Axis axis) from Uruguay in a 2-year period (2020-2022) and examined the role of this invasive species as a new potential reservoir of the virus. In addition, with the aim to gain new insights into viral ecology in the context of One Health, by using camera trapping, we identified and quantified temporal and spatial coexistence of spotted deer, wild boars, and cattle. In free-living animals, we detected an anti-HEV seropositivity of 11.1% (6/54). HEV infection and viral excretion in feces were assessed by RT-PCR. Thirteen of 19 samples (68.4%) had HEV RNA. Six samples were amplified using a broadly reactive RT-PCR and sequenced. No captive animal showed evidence of HEV infection. Additionally, HEV RNA was detected in a freshwater pond shared by these species. Phylogenetic and p-distance analysis revealed that zoonotic HEV genotype 3 strains circulate together with unclassified variants related to moose HEV whose potential risk of transmission to humans and other domestic and wild animals is unknown. The data presented here suggest that spotted deer (A. axis) may be a novel host for zoonotic HEV strains.

Evidence of Circulation and Phylogenetic Analysis of Hepatitis E Virus (HEV) in Wild Boar in South-East Italy

Hepatitis E virus (HEV) is an important cause of acute viral hepatitis in humans worldwide. The food-borne transmission of HEV appears to be a major route in Europe through the consumption of pork and wild boar meat. HEV epidemiology in wild boars has been investigated mainly in Northern and Central Italian regions, whilst information from Southern Italy is limited. We investigated the occurrence of HEV in wild boar in the Apulia and Basilicata regions (Southern Italy). Thirteen (10.4%) out of one hundred and twenty-five wild boar samples tested positive for HEV using a quantitative reverse transcription PCR. HEV prevalence was 12% in Apulia and 9.3% in Basilicata. Seven samples were genotyped, and different subtypes (c, f, m) of genotype 3 were identified. The complete genome of a 3m strain was determined, and the virus showed the highest nucleotide identity to a human HEV strain identified in France in 2017. These findings demonstrate the substantial circulation of HEV in the wild boar population in Italian Southern regions. Gathering information on the HEV strains circulating in different geographical areas is useful for tracking the origin of HEV outbreaks and assessing the epidemiological role of wild boar as a potential virus reservoir for domestic pigs.

First serological and molecular investigation of hepatitis E virus infection in dromedary camels in Algeria

Hepatitis E is an acute self-limited or fulminant infection in humans, caused by the hepatitis E virus (HEV). This member of the Hepeviridae family has been identified in a wide range of domestic and wild animals all over the world, with a possible transmission to humans through fecal oral route, direct contact and ingestion of contaminated meat products, making it one of the global zoonotic and public health major concerns. Since there is no monitoring program and a lack of data on HEV in animals in Algeria, the current preliminary survey has been undertaken to elucidate the exposure to the virus in camels at abattoirs of six southern provinces of Algeria. Two-hundred and eight sera/plasma were collected and analyzed (by double antigen sandwich ELISA) for the presence of total anti-HEV antibodies, among which 35.1% were positive, but no HEV RNA could be isolated from them (by two pan-HEV nested RT-PCR and broad range real-time reverse transcription RT-PCR). The univariate analysis showed significant associations (p < 0.05) between HEV seroprevalence and province of origin, age, and sex of camels, whereas the multivariable logistic regression analysis revealed a negative impact of camels' age on it. The obtained results confirm that HEV infection is widespread established in the camelid population of Algeria.

Tracing the History of Hepatitis E Virus Infection in Mexico: From the Enigmatic Genotype 2 to the Current Disease Situation

Hepatitis E virus (HEV) is the major cause of acute viral hepatitis worldwide. This virus is responsible for waterborne outbreaks in low-income countries and zoonosis transmission in industrialized regions. Initially, considered self-limiting, HEV may also lead to chronic disease, and evidence supports that infection can be considered a systemic disease. In the late 1980s, Mexico became a hot spot in the study of HEV due to one of the first virus outbreaks in Latin America related to enterically transmitted viral non-A, non-B hepatitis. Viral stool particles recovered from Mexican viral hepatitis outbreaks represented the first identification of HEV genotype (Gt) 2 (Gt2) in the world. No new findings of HEV-Gt2 have been reported in the country, whereas this genotype has been found in countries on the African continent. Recent investigations in Mexico have identified other strains (HEV-Gt1 and -Gt3) and a high frequency of anti-HEV antibodies in animal and human populations. Herein, the potential reasons for the disappearance of HEV-Gt2 in Mexico and the advances in the study of HEV in the country are discussed along with challenges in studying this neglected pathogen. These pieces of information are expected to contribute to disease control in the entire Latin American region.

Rat Hepatitis E Virus in Norway Rats, Ontario, Canada, 2018-2021

We tested liver samples from 372 Norway rats (Rattus norvegicus) from southern Ontario, Canada, during 2018-2021 to investigate presence of hepatitis E virus infection. Overall, 21 (5.6%) rats tested positive for the virus. Sequence analysis demonstrated all infections to be rat hepatitis E virus (Rocahepevirus ratti genotype C1).

Development and Application of a Nanobody-Based Competitive ELISA for Detecting Antibodies against Hepatitis E Virus from Humans and Domestic Animals

Hepatitis E virus (HEV) is a zoonotic pathogen that is widespread worldwide. At present, most enzyme-linked immunosorbent assay (ELISA) kits only detect antibodies against human HEV. In this study, a nanobody-horseradish peroxidase (HRP) fusion protein-based competitive ELISA (cELISA) with more convenience and spectral characteristics for HEV antibody detection was developed and used to detect HEV IgG in various species. First, 6 anti-swine HEV capsid protein nanobodies were screened using phage display technology from an immunized Bactrian camel. Then, HEV-Nb67-HRP fusions were expressed and used as a probe for developing a cELISA. The cutoff value of the cELISA was 17.8%, and there was no cross-reaction with other anti-swine virus antibodies, suggesting that the cELISA had good specificity. The intra-assay and interassay coefficients of variation (CVs) were 1.33 to 5.06% and 1.52 to 6.84%, respectively. The cELISA and Western blot showed a higher coincidence rate (97.14%, kappa value = 0.927) than cELISA and indirect ELISA (95.00%, kappa value = 0.876) in clinical swine serum samples. Finally, the seroprevalence of HEV IgG in humans, pigs, rabbits, cows, and goats was 30.67%, 19.26%, 8.75%, 27.59%, and 18.08%, respectively, suggesting that cELISA may have a broader scale for mammalian HEV antibody detection. These results suggest that the newly developed cELISA was rapid, low-cost, reliable, and useful for the serological evaluation of current HEV. IMPORTANCE HEV is thought to be a zoonotic infection and is widespread worldwide; it is beneficial to establish a more convenient and spectral method for HEV antibody detection. In this study, a convenient, time-saving, reproducible, highly sensitive, specific, and novel nanobody-based cELISA was developed and can be used to detect IgG antibodies against mammalian HEV. It provides a new technique for serological evaluation and ELISA-based diagnosis of HEV infection.

Hepatitis E Virus (HEV) Infection among Humans and Animals: Epidemiology, Clinical Characteristics, Treatment, and Prevention

The public health significance of hepatitis E is very important [...].

[Viral zoonoses in Germany: a One Health perspective]

The COVID-19 pandemic and the increasing occurrence of monkeypox (mpox) diseases outside Africa have illustrated the vulnerability of populations to zoonotic pathogens. In addition, other viral zoonotic pathogens have gained importance in recent years.This review article addresses six notifiable viral zoonotic pathogens as examples to highlight the need for the One Health approach in order to understand the epidemiology of the diseases and to derive recommendations for action by the public health service. The importance of environmental factors, reservoirs, and vectors is emphasized, the diseases in livestock and wildlife are analyzed, and the occurrence and frequency of diseases in the population are described. The pathogens selected here differ in their reservoirs and the role of vectors for transmission, the impact of infections on farm animals, and the disease patterns observed in humans. In addition to zoonotic pathogens that have been known in Germany for a long time or were introduced recently, pathogens whose zoonotic potential has only lately been shown are also considered.For the pathogens discussed here, there are still large knowledge gaps regarding the transmission routes. Future One Health-based studies must contribute to the further elucidation of their transmission routes and the development of prevention measures. The holistic approach does not necessarily include a focus on viral pathogens/diseases, but also includes the question of the interaction of viral, bacterial, and other pathogens, including antibiotic resistance and host microbiomes.

Optimization of the molecular diagnosis of the acute hepatitis E virus infection

To evaluate the diagnostic value of the combination of two broad-range PCR assays targeting two different and conserved regions of the viral genome for the diagnosis of acute Hepatitis E virus (HEV) infection. Patients with acute hepatitis were prospectively recruited. In all, HEV-IgM antibodies were tested together with evaluation of HEV viraemia by two PCR assays (ORF3 and ORF1). The number of individuals exhibiting negative IgM antibody results but carrying viral RNA was calculated by each PCR assay. Four-hundred and seventy individuals were included, of whom 145 (30.8%) were diagnosed as having acute HEV. Of them, 122 (84.1%) exhibited HEV-IgM antibodies, and 81 (55.8%) had detectable viral RNA for at least one PCR. Using the ORF3 molecular assay, 70 (48.3%) individuals were identified with HEV infection. When the ORF1 molecular assay was applied, 49 (33.8%) individuals were identified. The ORF3 assay detected viral RNA in 32 patients not detected by the ORF1 assay. In contrast, the ORF1 assay could amplify viral RNA in 11 patients who were not detected by the ORF3 assay. The parallel use of two broad-range PCR assays significantly increased the performance of the molecular diagnosis of HEV.

Open Reading Frame 4 Is Not Essential in the Replication and Infection of Genotype 1 Hepatitis E Virus

Genotype 1 hepatitis E virus (HEV-1), unlike other genotypes of HEV, has a unique small open reading frame known as ORF4 whose function is not yet known. ORF4 is located in an out-framed manner in the middle of ORF1, which encodes putative 90 to 158 amino acids depending on the strains. To explore the role of ORF4 in HEV-1 replication and infection, we cloned the complete genome of wild-type HEV-1 downstream of a T7 RNA polymerase promoter, and the following ORF4 mutant constructs were prepared: the first construct had TTG instead of the initiation codon ATG (A2836T), introducing an M→L mutation in ORF4 and a D→V mutation in ORF1. The second construct had ACG instead of the ATG codon (T2837C), introducing an M→T mutation in ORF4. The third construct had ACG instead of the second in-frame ATG codon (T2885C), introducing an M→T mutation in ORF4. The fourth construct contained two mutations (T2837C and T2885C) accompanying two M→T mutations in ORF4. For the latter three constructs, the accompanied mutations introduced in ORF1 were all synonymous changes. The capped entire genomic RNAs were generated by in vitro transcription and used to transfect PLC/PRF/5 cells. Three mRNAs containing synonymous mutations in ORF1, i.e., T2837C^RNA, T2885C^RNA, and T2837C/T2885C^RNA, replicated normally in PLC/PRF/5 cells and generated infectious viruses that successfully infected Mongolian gerbils as the wild-type HEV-1 did. In contrast, the mutant RNA, i.e., A2836T^RNA, accompanying an amino acid change (D937V) in ORF1 generated infectious viruses upon transfection, but they replicated slower than the wild-type HEV-1 and failed to infect Mongolian gerbils. No putative viral protein(s) derived from ORF4 were detected in the wild-type HEV-1- as well as the mutant virus-infected PLC/PRF/5 cells by Western blot analysis using a high-titer anti-HEV-1 IgG antibody. These results demonstrated that the ORF4-defective HEV-1s had the ability to replicate in the cultured cells, and that these defective viruses had the ability to infect Mongolian gerbils unless the overlapping ORF1 was accompanied by non-synonymous mutation(s), confirming that ORF4 is not essential in the replication and infection of HEV-1.

Epidemiological and genetic evaluation of HEV in swine slaughtered in Sicily region (Italy)

Hepatitis E virus (HEV) is the etiological agent of acute viral hepatitis, a disease transmitted by the oral-faecal route. In Europe, zoonotic transmission of HEV-3 genotype is associated with the consumption of raw or slightly cooked meat of pigs and wild boars that are considered the main reservoirs. This work aims to assess the occurrence of swines' HEV RNA liver samples and rectal swabs slaughtered in Sicily using biomolecular methods. HEV-RNA was detected in 17.5 % (21/120) liver samples analyzed and in 3.7 % (3/81) rectal swabs examined. All positive samples were predicted as genotype 3 and subtype 3c (75 %). These data suggest a potential HEV transmission to humans through close contact with pig breeders, veterinarians, slaughterhouse personnel, and pork meat product consumption. Moreover, there are few scientific data evaluating the HEV spread around pigs and humans in Sicily. Therefore, further studies are necessary to correlate humans with swine serotypes and to assess the HEV presence and persistence in food and the risk during the slaughtering process. These surveys allow to clarify the role of the swine species as a potential source of infection for other domestic or wild animals and humans and to establish possible control measures throughout the food chain.

Substantial viral and bacterial diversity at the bat-tick interface

Ticks harbour a high diversity of viruses, bacteria and protozoa. The soft tick Carios vespertilionis (Argasidae) is a common ectoparasite of bats in the Palearctic region and is suspected to be vector and reservoir of viruses and other microbial species in bat populations, some of which may act as zoonotic agents for human disease. The Soprano pipistrelle (Pipistrellus pygmaeus, Vespertilionidae) is widely distributed in Europe, where it can be found inside or close to human habitation. We used meta-transcriptomic sequencing to determine the RNA virome and common microbiota in blood-fed C. vespertilionis ticks collected from a Soprano pipistrelle bat roosting site in south-central Sweden. Our analyses identified 16 viruses from 11 virus families, of which 15 viruses were novel. For the first time in Sweden we identified Issuk-Kul virus, a zoonotic arthropod-borne virus previously associated with outbreaks of acute febrile illness in humans. Probable bat-associated and tick-borne viruses were classified within the families Nairoviridae, Caliciviridae and Hepeviridae, while other invertebrate-associated viruses included members of the Dicistroviridae, Iflaviridae, Nodaviridae, Partitiviridae, Permutotetraviridae, Polycipiviridae and Solemoviridae. Similarly, we found abundant bacteria in C. vespertilionis, including genera with known tick-borne bacteria, such as Coxiella spp. and Rickettsia spp. These findings demonstrate the remarkable diversity of RNA viruses and bacteria present in C. vespertilionis and highlight the importance of bat-associated ectoparasite surveillance as an effective and non-invasive means to track viruses and bacteria circulating in bats and ticks.

Hepatitis E Virus Research in Brazil: Looking Back and Forwards

Hepatitis E virus (HEV) has emerged as a public health concern in Brazil. From the first identification and characterization of porcine and human HEV-3 strains in the 2000s, new HEV subtypes have been identified from animal, human, and environmental isolates. As new potential animal reservoirs have emerged, there is a need to compile evidence on the zoonotic dissemination of the virus in animal hosts and the environment. The increasing amount of seroprevalence data on sampled and randomly selected populations must be systematically retrieved, interpreted, and considered under the One Health concept. This review focused on HEV seroprevalence data in distinct animal reservoirs and human populations reported in the last two decades. Furthermore, the expertise with experimental infection models using non-human primates may provide new insights into HEV pathogenesis, prevention, and environmental surveillance.

Hepatitis E Virus (HEV) in Makkah, Saudi Arabia: A Population-Based Seroprevalence Study

BACKGROUND

The Hepatitis E virus (HEV) is a common cause of viral hepatitis worldwide. Little is known about the seroprevalence of HEV in the general population of Saudi Arabia.

METHODS

A community-based cross-sectional HEV seroprevalence study was conducted in Makkah, Saudi Arabia. Anti-HEV IgG antibodies were detected in sera using an in-house ELISA. The frequency of HEV sageerology and its correlation with demographic, and environmental factors were evaluated.

RESULTS

Enrollment consisted of 1329 individuals, ages ranged from 8 to 88 years, the mean age was 30.17 years, the median age was 28yrs, and the male: female ratio was 1.15. The overall seroprevalence was 23.8% (316/1329). Males had significantly higher seroprevalence than females (66.1 vs. 33.9%; p < 0.001). Seroprevalence had significant correlations with age, occupation, and lack of regular water supply and housing conditions.

CONCLUSIONS

This is the first HEV community-based seroprevalence study from Saudi Arabia. Results show that the HEV is endemic in Makkah and affects all age groups and occupations. HEV affects more males than females and those living in crowded accommodations without a regular supply of water. Further studies are required across all regions of Saudi Arabia to determine the country's seroprevalence of active or past infection using tests for HEV IgG, HEV IgM antibodies and/or HEV RNA and underlying determinants of transmission.

Puzzles for Hepatitis E Virus

Hepatitis E virus (HEV) is an important but understudied virus that has been the major cause of acute viral hepatitis worldwide. In recent decades, our understanding of this neglected virus has changed greatly: novel forms of viral proteins and their functions have been discovered; HEV can transmit via blood transfusion and organ transplantation; HEV can infect many animal species and the number is still increasing; HEV can induce chronic hepatitis and extra-hepatic manifestations. However, we are short of effective treatment measures to counter the virus. In this chapter we tend to briefly introduce the puzzles and major knowledge gaps existed in the field of HEV research.

Hepatitis E as a Zoonosis

Hepatitis E viruses in the family of Hepeviridae have been classified into 2 genus, 5 species, and 13 genotypes, involving different animal hosts of different habitats. Among all these genotypes, four (genotypes 3, 4, 7, and C1) of them are confirmed zoonotic causing sporadic human diseases, two (genotypes 5 and 8) were likely zoonotic showing experimental animal infections, and the other seven were not zoonotic or unconfirmed. These zoonotic HEV carrying hosts include pig, boar, deer, rabbit, camel, and rat. Taxonomically, all the zoonotic HEVs belong to the genus Orthohepevirus, which include genotypes 3, 4, 5, 7, 8 HEV in the species A and genotype C1 HEV in the species C. In the chapter, information of zoonotic HEV such as swine HEV (genotype 3 and 4), wild boar HEV (genotypes 3-6), rabbit HEV (genotype 3), camel HEV (genotype 7 and 8), and rat HEV (HEV-C1) was provided in detail. At the same time, their prevalence characteristics, transmission route, phylogenetic relationship, and detection technology were discussed. Other animal hosts of HEVs were introduced briefly in the chapter. All these information help peer researchers have basic understanding of zoonotic HEV and adopt reasonable strategy of surveillance and prevention.

Genetic Evolution of Hepatitis E Virus

Comparative analysis of the genomic sequences of multiple hepatitis E virus (HEV) isolates has revealed extensive genomic diversity among them. Recently, a variety of genetically distinct HEV variants have also been isolated and identified from large numbers of animal species, including birds, rabbits, rats, ferrets, bats, cutthroat trout, and camels, among others. Furthermore, it has been reported that recombination in HEV genomes takes place in animals and in human patients. Also, chronic HEV infection in immunocompromised individuals has revealed the presence of viral strains carrying insertions from human genes. This paper reviews current knowledge on the genomic variability and evolution of HEV.

Hepatitis E Virus

Since the sequence of hepatitis E virus (HEV) was determined from a patient with enterically transmitted non-A, non-B hepatitis in 1989, similar sequences have been isolated from many different animals, including pigs, wild boars, deer, rabbits, bats, rats, chicken, and trout. All of these sequences have the same genomic organization, which contains open reading frames (ORFs) 1, 2, and 3, although their genomic sequences are variable. Some have proposed that they be classified as new family, Hepeviridae, which would be further divided into different genera and species according to their sequence variability. The size of these virus particles generally ranged from 27 to 34 nm. However, HEV virions produced in cell culture differ in structure from the viruses found in feces. Those from cell culture have a lipid envelope and either lack or have a little ORF3, whereas the viruses isolated from feces lack a lipid envelope but have ORF3 on their surfaces. Surprisingly, most of the secreted ORF2 proteins from both these sources are not associated with HEV RNA.

Prevalence of Hepatitis E Virus (HEV) in Feral and Farmed Wild Boars in Xinjiang, Northwest China

Hepatitis E virus (HEV) causes infections in humans and a wide range of animal hosts. Wild boar is an important natural reservoir of HEV genotypes 3−6 (HEV-3−HEV-6), but comparative analysis of HEV infections in both feral and farmed wild boars remains limited. In this study, samples from 599 wild boars were collected during 2017−2020, including 121 feral wild boars (collected 121 fecal, 121 serum, and 89 liver samples) and 478 farmed wild boars (collected 478 fecal and 478 serum samples). The presence of anti-HEV IgG antibodies were detected by the HEV-IgG enzyme-linked immunosorbent assay (ELISA) kit. HEV RNA was detected by reverse transcription polymerase chain reaction (RT-PCR), targeting the partial ORF1 genes from fecal and liver samples, and the obtained genes were further genotyped by phylogenetic analysis. The results showed that 76.2% (95% CI 72.1−79.9) of farmed wild boars tested anti-HEV IgG seropositive, higher than that in feral wild boars (42.1%, 95% CI 33.2−51.5, p < 0.001). HEV seropositivity increased with age. Wild boar HEV infection presented a significant geographical difference (p < 0.001), but not between sex (p = 0.656) and age (p = 0.347). HEV RNA in fecal samples was detected in 13 (2.2%, 95% CI 1.2−3.7) out of 599 wild boars: 0.8% (95% CI 0.0−4.5, 1/121) of feral wild boars and 2.5% (95% CI 1.3−4.3, 12/478) of farmed wild boars. Phylogenetic analysis showed that all these viruses belonged to genotype HEV-4, and further grouped into sub-genotypes HEV-4a, HEV-4d, and HEV-4h, of which HEV-4a was first discovered in the wild boar populations in China. Our results suggested that farms could be a setting for amplification of HEV. The risk of HEV zoonotic transmission via rearing and consumption of farmed wild boars should be further assessed.

Development and characterization of secondary standards for nucleic acid amplification technology (NAAT) assays for detection of hepatitis E virus

BACKGROUND

To harmonize assays for detection of HEV RNA, a World Health Organization International Standard (WHO IS) was established. The WHO IS represents the highest order standard for HEV RNA but is limited in quantity. Secondary standards are needed to limit the use of WHO IS and minimize the need to replace it.

OBJECTIVE

Establish secondary standards for HEV NAAT assays and to calibrate these against the WHO IS.

METHODS

Stocks of genotype 3 HEV were prepared using both cell lysates and cell culture supernatants to produce non-enveloped and quasi-enveloped virus stocks, respectively. Both stocks were heat-inactivated, diluted in negative human plasma, and lyophilized to produce two candidate secondary standards: HEV-RR (non-enveloped virus) and HEV-RR.1 (quasi-enveloped virus). Both candidate standards were characterized and calibrated against the WHO IS for HEV RNA in an international collaborative study.

RESULTS

The collaborative study returned a total of 15 data sets, with different RNA extraction and amplification methods. The estimated mean values relative to the WHO IS (250,000 IU/ml) are 229,000 IU/ml and 355,000 IU/ml for HEV-RR and HEV-RR.1, respectively.

CONCLUSION

We have established two secondary standards for HEV RNA calibrated against the WHO IS. These standards are non-infectious and stable under different storage temperatures.

Hepatitis E virus species barriers: seeking viral and host determinants

The intimate relationship between virus and host cell can result in highly adapted viruses that are restricted to a single host. However, some viruses have the ability to infect multiple host species. Remarkably, hepatitis E viruses (HEV) comprise genotypes that are either 'single-host' or 'multi-host' genotypes, a trait that raises fundamental questions: Why do different genotypes differ in their host range, despite a high degree of genomic similarity? What are the underlying molecular determinants that shape species barriers? Here, we review the current knowledge of viral and host determinants that may affect the evolutionary trajectories of HEV. We also provide a perspective on techniques and methods that address open questions of HEV host range and adaptation.

Characterization of Pipistrellus pygmaeus Bat Virome from Sweden

Increasing amounts of data indicate that bats harbor a higher viral diversity relative to other mammalian orders, and they have been recognized as potential reservoirs for pathogenic viruses, such as the Hendra, Nipah, Marburg, and SARS-CoV viruses. Here, we present the first viral metagenomic analysis of Pipistrellus pygmaeus from Uppsala, Sweden. Total RNA was extracted from the saliva and feces of individual bats and analyzed using Illumina sequencing. The results identified sequences related to 51 different viral families, including vertebrate, invertebrate, and plant viruses. These viral families include Coronaviridae, Picornaviridae, Dicistroviridae, Astroviridae, Hepeviridae, Reoviridae, Botourmiaviridae, Lispviridae, Totiviridae, Botoumiaviridae, Parvoviridae, Retroviridae, Adenoviridae, and Partitiviridae, as well as different unclassified viruses. We further characterized three near full-length genome sequences of bat coronaviruses. A phylogenetic analysis showed that these belonged to alphacoronaviruses with the closest similarity (78–99% at the protein level) to Danish and Finnish bat coronaviruses detected in Pipistrellus and Myotis bats. In addition, the full-length and the near full-length genomes of picornavirus were characterized. These showed the closest similarity (88–94% at the protein level) to bat picornaviruses identified in Chinese bats. Altogether, the results of this study show that Swedish Pipistrellus bats harbor a great diversity of viruses, some of which are closely related to mammalian viruses. This study expands our knowledge on the bat population virome and improves our understanding of the evolution and transmission of viruses among bats and to other species.

Genetic diversity of hepatitis E virus (HEV) in imported and domestic camels in Saudi Arabia

Camels gained attention since the discovery of MERS-CoV as intermediary hosts for potentially epidemic zoonotic viruses. DcHEV is a novel zoonotic pathogen associated with camel contact. This study aimed to genetically characterize DcHEV in domestic and imported camels in Saudi Arabia. DcHEV was detected by RT-PCR in serum samples, PCR-positive samples were subjected to sequencing and phylogenetic analyses. DcHEV was detected in 1.77% of samples with higher positivity in domestic DCs. All positive imported dromedaries were from Sudan with age declining prevalence. Domestic DcHEV sequences clustered with sequences from Kenya, Somalia, and UAE while imported sequences clustered with one DcHEV isolate from UAE and both sequences clustered away from isolates reported from Pakistan. Full-genome sequences showed 24 amino acid difference with reference sequences. Our results confirm the detection of DcHEV in domestic and imported DCs. Further investigations are needed in human and camel populations to identify DcHEV potential zoonosis threat.

Chirohepevirus from Bats: Insights into Hepatitis E Virus Diversity and Evolution

Homologs of the human hepatitis E virus (HEV) have been identified in more than a dozen animal species. Some of them have been evidenced to cross species barriers and infect humans. Zoonotic HEV infections cause chronic liver diseases as well as a broad range of extrahepatic manifestations, which increasingly become significant clinical problems. Bats comprise approximately one-fifth of all named mammal species and are unique in their distinct immune response to viral infection. Most importantly, they are natural reservoirs of several highly pathogenic viruses, which have induced severe human diseases. Since the first discovery of HEV-related viruses in bats in 2012, multiple genetically divergent HEV variants have been reported in a total of 12 bat species over the last decade, which markedly expanded the host range of the HEV family and shed light on the evolutionary origin of human HEV. Meanwhile, bat-borne HEV also raised critical public health concerns about its zoonotic potential. Bat HEV strains resemble genomic features but exhibit considerable heterogeneity. Due to the close evolutionary relationships, bat HEV altogether has been recently assigned to an independent genus, Chirohepevirus. This review focuses on the current state of bat HEV and provides novel insights into HEV genetic diversity and molecular evolution.

Serological and molecular survey of hepatitis E virus in cats and dogs in Spain

Hepatitis E virus (HEV) is an emerging zoonotic pathogen that is currently recognized as one of the major causes of acute human hepatitis worldwide. In Europe, the increasing number of hepatitis E cases is mainly associated with the consumption of animal food products or contact with infected animals. Dogs and cats have been suggested as a zoonotic source of HEV infection. The aim of this study was to assess Orthohepevirus circulation, including HEV-A, HEV-B and HEV-C species, in sympatric urban cats and dogs in southern Spain. Between 2017 and 2020, blood samples were collected from 144 stray cats and 152 dogs, both strays and pets. The presence of antibodies against HEV were tested using a double-antigen sandwich ELISA and seropositive samples were further analyzed by western blot. A RT-PCR was performed to detect RNA of Orthohepevirus species (HEV-A, HEV-B and HEV-C). A total of 19 (6.4%; 95%CI: 3.6-9.2) of the 296 animals tested showed anti-HEV antibodies by ELISA. Seropositivity was significantly higher in dogs (9.9%; 15/152; 95%CI: 5.1-14.6) than in cats (2.8%; 4/144; 95%CI: 0.1-5.5). Ten out of the 18 ELISA-positive animals that could be further analyzed by western blot, reacted against HEV-3 and/or HEV-C1 antigens, which suggest circulation of both genotypes in urban cats and dogs in the study area. However, HEV-A, HEV-B and HEV-C RNA was not detected in any of the tested sera. This is the first study to assess HEV circulation in both stray cats and dogs in Europe. Our results provide evidence of HEV exposure in sympatric urban cat and dog populations in southern Spain. Further studies are needed to determine the role of these species in the epidemiology of HEV. This article is protected by copyright. All rights reserved.

Molecular Identification and Characterization of a Genotype 3 Hepatitis E Virus (HEV) Strain Detected in a Wolf Faecal Sample, Italy

Hepatitis E virus (HEV) infection is a major health problem worldwide. In developed countries, zoonotic transmission of HEV genotypes (Gt) 3 and 4 is caused by the ingestion of raw or undercooked meat of infected pigs and wild boars, the main reservoirs of HEV. However, additional animals may harbour HEV or HEV-related strains, including carnivores. In this study, we investigated the molecular epidemiology of orthohepeviruses in wild canids by screening a total of 136 archival faecal samples, collected from wolves (42) and red foxes (94) in Northwestern Italy. Orthohepevirus RNA was identified in a faecal specimen, collected from a wolf carcass in the province of La Spezia (Liguria Region, Italy). The nearly full-length (7212 nucleotides) genome of the strain HEV/81236/Wolf/2019/ITA (GenBank accession no. MZ463196) was determined by combining a sequence-independent single-primer amplification (SISPA) approach with the Oxford Nanopore Technologies sequencing platform. Upon phylogenetic analysis, the HEV detected in wolf was segregated into clade HEV-3.1, displaying the highest nucleotide (nt) identity (89.0-93.3%) to Gt3 strains belonging to subtype c. Interestingly, the wolf faecal sample also contained porcine astrovirus sequences, endorsing the hypothesis of a dietary origin of the HEV strain due to preying habits.

Hepatitis E virus infection increases the risk of diabetes and severity of liver disease in patients with chronic hepatitis C virus infection

OBJECTIVES

Co-infection with hepatitis A or B viruses may aggravate liver injury in patients infected with hepatitis C virus (HCV). However, few studies have assessed co-infection with hepatitis E virus (HEV) and HCV. Therefore, this study aimed to assess the prevalence and impact of HEV infection among Brazilian patients with chronic HCV infection.

METHODS

This observational study included adult patients with chronic HCV infection who were naive to antiviral therapy from January 2013 to March 2016. A total of 181 patients were enrolled, and HEV serology and PCR were performed for all patients.

RESULTS

Seropositivity for anti-HEV IgG was detected in 22 (12.0%) patients and anti-HEV immunoglobulin M in 3 (1.6%). HEV RNA showed inconclusive results in nine (4.9%) patients and was undetectable in the remaining patients. HEV serology positive patients had more severe liver disease, characterized by liver fibrosis ≥3 versus ≤2 (p<0.001), Aspartate Aminotransferase-to-Platelet Ratio Index of ≥1.45 (p=0.003), and Fibrosis-4 score of ≥3.25 (p=0.001). Additionally, the odds of HEV-positive patients developing diabetes mellitus were 3.65 (95% CI 1.40-9.52) times the corresponding odds of HEV-negative patients. A case-control-based histological analysis (n=11 HEV-HCV-positive patients and n=22 HCV-positive patients) showed no significant differences between the groups.

CONCLUSIONS

This prevalence is higher than that reported in previous studies of the general population in Brazil. Thus, HEV infection may influence the severity of liver disease and may represent an additional risk of developing diabetes mellitus in patients with HCV infection.

A Molecular Study on Hepatitis E Virus (HEV) in Pigs in Bulgaria

Information on hepatitis E virus (HEV) strains circulating in animal reservoirs in Bulgaria is currently lacking. Herein, by screening HEV seropositive sera obtained from Bulgarian swine and wild boars, viral RNA was detected at high prevalence rate (28.2%) in industrial pigs. Sequence analysis of the partial polymerase (RdRp) region revealed the highest genetic correlation with HEVs of genotype (Gt) 3 identified in French and Dutch patients. For three such strains, a 700-bp fragment of the open reading frame 2 gene was generated. On phylogenetic analysis, the Bulgarian strains clustered tightly (93.8-98.3% nt) with human and animal HEVs classified within the Gt3 subtype c.