A broadly reactive one-step real-time RT-PCR assay for rapid and sensitive detection of hepatitis E virus

Distinct distribution of HEV-3 subtypes across humans, animals, and environmental waters in Sweden

We previously observed a notable discrepancy in the distribution of HEV-3 subtypes between wastewater and clinical samples in Sweden. To confirm this observation and comprehensively elucidate HEV-3 circulation patterns across humans, animals, and environmental waters in Sweden, we analysed the HEV genetic diversity in archived wastewater samples between late 2016 and early 2018, clinical cases between 2012 and 2024, and all available Swedish sequences from the NCBI Virus database. HEV RNA was detected in all archived wastewater samples, with subtype 3c being the only subtype identified. In typed clinical cases, subtypes 3f (45/126) and 3c (44/126) were nearly equally distributed, though regional dominance varied. When incorporating human sequences from other Swedish studies, subtype 3f became dominant (75/168). Analysis of all available sequences revealed that 3f (113/136) was the dominant subtype in Sus scrofa (pigs and wild boars), while 3c (30/33) was dominant in environmental waters. These findings highlight the complex transmission dynamics of HEV-3 in Sweden. The near-absence of 3c in Swedish domestic pigs and wild boars, despite its high proportion in clinical cases, raises the question about the source of human 3c infection. In addition, the near-exclusive detection of 3c in wastewater suggests potential differences in viral shedding, disease severity of HEV-3 subtypes, or alternative host sources. This study emphasizes the importance of integrated One Health surveillance to track HEV circulation across reservoirs.

Pathological Characteristics of Pregnant Tree Shrews Infected by Zoonotic Hepatitis E Virus Genotype and the Effect of Estrogen on Virus Replication

Hepatitis E, caused by the hepatitis E virus (HEV), is a zoonotic disease that extends beyond hepatocellular necrosis to replicate in multiple organs. While most infections are self-limiting, HEV infection during pregnancy is associated with severe outcomes, including acute liver failure, preterm delivery, and miscarriage, with the mechanisms underlying this high pathogenicity remaining poorly understood. This study established a pregnant tree shrew model with a late-stage HEV infection and a cellular model using zoonotic HEV genotypes GT3 and GT4 to investigate the effects of estrogen on HEV replication. Results showed that negative-strand RNA detection revealed replicative intermediates in feces and tissues during the acute phase, with peak viral loads occurring within one week and the highest titers in bile. Serum alanine aminotransferase (ALT) and aspartate aminotransferase (AST) levels rose at 3 days post-inoculation (DPI), peaking at 7 DPI. Elevated estrogen levels post-miscarriage correlated with increased viral loads, a trend mirrored in cell culture models showing linear relationships between estrogen and viral replication. Histopathology demonstrated viral hepatitis lesions in liver tissues and abnormalities in the uterus, ovaries, and brain, including hydropic degeneration, neuronal disruption, and granulosa cell necrosis. This study developed a pregnant tree shrew model for HEV infection, providing a robust tool for exploring pathogenic mechanisms during pregnancy and genotype-specific differences in zoonotic HEV pathogenicity. These findings offer new insights into the role of estrogen in HEV replication and its contribution to adverse pregnancy outcomes.

Structural basis for hepatitis E virus neutralization by potent human antibodies

Antibodies targeting the hepatitis E virus (HEV) surface capsid protein (CA) are essential for infection control and resolution, yet their molecular and functional attributes remain largely elusive. We characterized 144 human HEV-CA-specific monoclonal antibodies cloned from the memory B cells of HEV-exposed individuals. Most human anti-CA antibodies cross-reacted with all HEV genotype variants, and a subset also recognized the zoonotic rat hepatitis E virus. HEV antibody repertoire was diverse and contained highly potent neutralizing antibodies binding to the CA protruding (P) domain. Structural analyses of CA protein complexed with three potent and broad HEV antibodies uncovered a neutralizing site located on monomeric P domain loops at the apex of the viral spike. These findings provide valuable insights into the protective humoral response to HEV and offer a framework for the rational design of HEV vaccines and immunotherapies.

Substantial spillover burden of rat hepatitis E virus in humans

The emergence of Rocahepevirus ratti genotype 1 (rat hepatitis E virus; rat HEV) in humans presents an unprecedented threat; however, the risk of rat HEV transmission to humans is not well understood. Here, we report the "Distinguishing Antibody Response Elicitation (DARE)" method, which distinguishes exposure to rat HEV. We use four study sets from China for large-scale population analysis: set 1 (hospital visit) and set 3 (ALT abnormality) from Yunnan province, a biodiversity hotspot, and set 2 (received physical examination) and set 4 (ALT abnormality) from Jiangsu province, a non-hotspot control region. rat HEV exposure risk is significantly higher in Yunnan, with 21.97% (190 of 865) in set 1 and 13.97% (70 of 501) in set 3, compared to 0.75% (9 of 1196) in Jiangsu's set 2. Six spillover infections for rat HEV are identified in set 1, with one case of abnormal ALT. The rat-1d strains carried by rats are closely related to those human infections. Our study reveals the substantial spillover burden posed by rat HEV in biodiversity hotspots and highlights the utility of DARE method for proactive surveillance of public health emergencies.

Trends and Challenges in the Detection and Environmental Surveillance of the Hepatitis E Virus

The Hepatitis E virus (HEV) is responsible for causing Hepatitis E, a zoonotic disease that has emerged as a significant global health concern, accounting for about 20 million infections and 70,000 deaths annually. Although it is often recognized as a disease that is acute in low-income countries, HEV has also been recognized as a zoonotic disease in high-income countries. The zoonotic transmission requires flexible approaches to effectively monitor the virus, vectors, and reservoirs. However, the environmental monitoring of HEV presents additional challenges due to limitations in current detection methods, making it difficult to accurately assess the global prevalence of the virus. These challenges hinder efforts to fully understand the scope of the disease and to implement effective control measures. This review will explore these and other critical concerns, addressing gaps in HEV research and highlighting the need for improved strategies in the monitoring, prevention, and management of Hepatitis E using a One Health approach.

Recent Hepatitis E Virus Infection in Wild Boars and Other Ungulates in Japan

Hepatitis E virus (HEV) is a zoonotic pathogen with multiple hosts, posing significant public health risks, especially in regions like Japan where game meat consumption is prevalent. This study investigated HEV infection and viral shedding in wild boars, sika deer, and Japanese serows across Japan. A total of 1896 serum samples were tested for anti-HEV antibodies, 1034 for HEV RNA, and 473 fecal samples for viral shedding. Anti-HEV antibodies were detected in wild boars from all seven prefectures studied, while HEV RNA was detected in wild boars from Fukuoka, Oita, and Miyazaki in southern Japan, as well as Yamaguchi prefecture. Genetic analysis revealed subtypes 3b, 4a, and 4g, with 3b being the most prevalent. Subtype 3b exhibited distinct geographical clustering, whereas 4g persisted exclusively in Yamaguchi for over 12 years. Infectious HEV particles were confirmed in wild boar feces, highlighting the risk of environmental contamination and zoonotic transmission. Sika deer showed no evidence of HEV infection, and only one Japanese serow tested positive for antibodies without detectable RNA. These findings underscore the importance of ongoing surveillance to assess the zoonotic risks from game meat consumption and prevention of HEV transmission to humans.

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.

The Impact of the Variability of RT-qPCR Standard Curves on Reliable Viral Detection in Wastewater Surveillance

Quantitative Polymerase Chain Reaction (qPCR) is a molecular technique that has become a gold standard in various disciplines, including environmental microbiology, due to its high sensitivity and specificity. In recent years, it has been extensively used in wastewater-based epidemiology to monitor the prevalence of different viruses in the population. In this study, we evaluated whether the no inclusion of a standard curve in each single experiment to reduce time and costs could have an impact on the accuracy of the results. Thirty independent RT-qPCR standard curve experiments using quantitative synthetic RNA material were conducted for seven different viruses, which include two targets of the novel SARS-CoV-2, hepatitis A and E, noroviruses genogroups I and II, human astrovirus, and rotavirus. Results showed that although all the viruses presented adequate efficiency rates (>90%), variability was also observed between them, independently of the viral concentration tested. NoVGII was the virus that presented the higher inter-assay variability in terms of efficiency while showing better sensitivity. In terms of heterogeneity in results, the two targets of SARS-CoV-2 showed the highest rates, being N2 the gene that presented the largest variability (CV 4.38-4.99%) and the lowest efficiency (90.97%). These findings indicate that including a standard curve in every experiment is recommended to obtain reliable results.

Uncovering the Prevalence and Genetic Characterization of Rabbit-Derived Paslahepevirus Balayani (Hepatitis E Virus) in Hebei Province, China

Paslahepevirus balayani (hepatitis E virus) is a zoonotic pathogen, with rabbit Paslahepevirus balayani (HEV-3ra) being widely distributed among global rabbit populations. Notably, in China, rabbits constitute a significant HEV host, second only to swine. Emerging evidence suggests that HEV-3ra possesses the capability to cross species barriers and infect humans. Against this backdrop, our investigation aimed to delineate the HEV infection status and epidemiological patterns in the commercial rabbits of Hebei Province, China. We collected 386 liver and 100 fecal samples across four regions in Hebei Province. Detection of HEV RNA in these specimens was achieved by employing reverse transcription quantitative polymerase chain reaction (RT-qPCR) and reverse transcription nested PCR (RT-Nested PCR), focusing on the amplification of a segment of the open reading frame 2 (ORF2) and the complete genome. Among the 486 samples, 73 were tested positive for HEV RNA, resulting in an overall positive rate of 15.0%. The positive rates for liver and fecal samples were 11.7% (45/386) and 28.0% (28/100), respectively. The study successfully obtained 38 partial ORF2 sequences and 5 complete genome sequences. Sequence analysis revealed that the complete genome sequences shared 86.0-94.5% nucleotide identity with HEV-3ra sequences in GenBank. Phylogenetic analysis confirmed that all strains belonged to HEV-3ra and were closely related to previously reported sequences from China. This study provides the first comprehensive genomic overview of circulating HEV-3ra strains in Hebei, offering valuable insights into the infection dynamics and prevalence of HEV-3ra among commercial rabbits, which can inform public health strategies.

Rapid visual detection of hepatitis E virus combining reverse transcription recombinase-aided amplification with lateral flow dipstick and real-time fluorescence

Hepatitis E virus (HEV) is a globally prevalent zoonotic pathogen that is primarily spread through the fecal-oral route, such as by consuming undercooked or contaminated pork. HEV infection leads to an estimated 3.3 million symptomatic cases of viral hepatitis and 70,000 deaths in human populations each year. Therefore, a rapid and accurate method for detecting HEV in serum or stool samples is essential. In this study, we aimed to develop and evaluate two methods for the rapid and convenient detection of HEV RNA: reverse transcription recombinase-aided amplification with lateral flow dipstick (RT-RAA-LFD) and quantitative real-time reverse transcription recombinase-aided amplification (qRT-RAA). We optimized the reaction conditions and assessed their sensitivity and specificity. The RT-RAA-LFD assay completed its reaction at 39°C within 15 minutes, achieving a 95% limit of detection (LOD) of 247 copies/μL. The qRT-RAA assay, completed at 42°C within 20 minutes, had a 95% LOD of 25 copies/μL. Both assays demonstrated no cross-reactivity with other porcine pathogens and exhibited strong specificity. In testing 245 porcine bile and fecal samples, the RT-RAA-LFD assay showed a kappa value of 0.943 (P < 0.001) with a 97.14% (238/245) coincidence rate compared with quantitative reverse transcription PCR. Similarly, the qRT-RAA assay achieved a kappa value of 0.976 (P < 0.001) with a 98.78% (242/245) coincidence rate. In conclusion, these two RT-RAA assays show promising potential as effective diagnostic tools for broad and efficient screening of swine HEV in veterinary clinics.

IMPORTANCE

Hepatitis E virus (HEV) is a globally widespread zoonotic pathogen that poses a significant public health risk. Swine serve as the primary natural host for zoonotic HEV. This study introduces a rapid and precise method for detecting swine HEV RNA, showcasing its potential as an effective diagnostic tool for comprehensive and efficient screening of swine HEV in veterinary clinics.

Burden of rodent-borne viruses in rodents and zoonotic risk in human in Cambodia: a descriptive and observational study

Background

Rodent-borne viruses, including hantaviruses, arenaviruses, and rodent hepatitis virus (HEV-C), pose significant health threats to humans, causing severe diseases such as hepatitis, respiratory illness, and hemorrhagic fevers. In Cambodia, data on these viruses remain limited, and their burdens on human health are unknown. This study investigated the presences of these viruses in rodents and assessed potential human exposure across diverse environmental and socio-economic contexts in Cambodia.

Methods

The study was conducted in urban, semi-urban, and rural areas of Cambodia during the rainy (2020) and dry seasons (2022). Rodents were screened for arenavirus, hantavirus, and HEV-C using RT-PCR. Human serum samples from the same site were tested for IgG antibodies using ELISA. Factors associated with virus spillover into humans were analyzed.

Findings

Among 750 rodents, 9.7% carried at least one virus: 5.2% arenavirus, 3.3% hantavirus, and 1.9% HEV-C. Infection rates were highest in urban (14.5%), followed by semi-urban (11.9%) and rural (2.1%) interfaces. Arenavirus was more prevalent during the rainy season, while hantavirus and HEV-C remained consistent across seasons. Seroprevalence in human was 12.7% for arenavirus, 10.0% for hantavirus, and 24.2% for HEV. Higher arenavirus seroprevalence was associated with urban recidency and lower education level. Hantavirus seroprevalence was associated with urban residency, acute hepatitis history, and flood-prone living areas. HEV seroprevalence increased with urban residency, increasing age, and medical condition history.

Interpretation

Our findings highlighted the need for rodent control, improved market infrastructure, enhanced waste management, and public awareness on hygiene practices and zoonotic risks, especially in urban and high-risk areas.

Determination of hepatitis E virus inactivation during manufacturing of spreadable pork liver sausage and salami-like raw pork sausage

The zoonotic hepatitis E virus (HEV) can cause acute and chronic hepatitis in humans. Meat from domestic pigs, which represent a major animal reservoir of HEV, plays a key role in HEV transmission. Although pork meat products can contain HEV-RNA, it is unknown whether infectious HEV is still present after their manufacturing process. Here, we used a newly developed method for virus extraction from sausages and a quantitative method for detecting HEV infectivity in artificially contaminated sausages to investigate the HEV inactivation during production of spreadable pork liver sausage and salami-like raw pork sausage. The cell culture-adapted HEV genotype 3c strain 47832c was used to contaminate meat preparations intended for production of sausages, which were manufactured based on recipes commonly used in Germany. According to these recipes, spreadable liver sausages of a certain diameter are to be held in a water bath at 70 °C for 30 min. Therefore, the HEV inoculated liver sausage preparations were filled into conical tubes and heated in a 70 °C water bath. After 21 min, the sausages reached a core temperature of 70 °C and samples were taken after further incubation for up to 18 min. For the raw sausages, the HEV inoculated meat preparation was filled into natural casings and sausages were cured at 18 °C and 80 % relative humidity. Samples were taken for up to 21 days. HEV was extracted from all samples, which were quantitatively analyzed for infectious virus and viral RNA using cell culture and RT-qPCR, respectively. During liver sausage production, infectious HEV decreased by four log10 immediately after reaching the core temperature of 70 °C and was completely inactivated (>4.3 log10 decrease) 2 min later (23 min heat treatment). In contrast, the HEV-RNA amount decreased only marginally (<0.6 log10) throughout the whole incubation time. During raw sausage manufacturing, infectious HEV decreased only slightly (<1.3 log10) over three weeks of curing, while the HEV-RNA amount remained unchanged. It can be concluded that the intended heating regime during production of spreadable liver sausages leads to an inactivation of HEV, indicating a low risk of HEV infection for consumers if these sausages are manufactured properly. In contrast, HEV was only slightly inactivated during production of salami-like raw pork sausage. Therefore, raw sausage can contain infectious HEV if starting material with a high HEV amount was used for production. Viral RNA testing cannot be used to predict infectivity of HEV in meat products.

Acute hepatitis E virus infection presenting as meningo-encephalitis

BACKGROUND

Acute hepatitis E infection (HEV), with its high incidence in Europe, should be considered as a differential diagnosis of acute viral hepatitis and can in some cases manifest with pronounced neurological symptoms.

CLINICAL CASE

We report on a 33-year-old female patient with severe arthralgia, myalgia, headache and psychomotor deterioration. Laboratory analyses showed elevated transaminases without signs of cholestasis. Acute hepatitis E virus infection was detected in serum. She reported fatigue and dysesthesias not responsive to analgesics. Cerebrospinal fluid (CSF) analysis revealed an inflammatory syndrome. HEV RNA was detected in the CSF. The infection remained mild, but dysesthesias persisted. Eight weeks after the first admission, the symptoms worsened again. Complete and sustained remission was achieved following intravenous corticosteroid treatment.

CONCLUSION

In patients with acute neurological symptoms and liver enzyme elevation, HEV infection should be considered. Neurologic symptoms such as fatigue, arthralgia, myalgia and dysesthesia along with psychomotor retardation should prompt CSF analysis.

Hepatitis E virus infection in immunosuppressed patients and its clinical manifestations

BACKGROUND & AIMS

Hepatitis E virus (HEV) is a main cause of acute hepatitis globally. However, immunosuppressed patients regularly develop chronic courses. The aim of this study was to analyse the current status of HEV diagnostics, characterize clinical manifestations and identify risk factors for complicated HEV infections.

METHODS

In this retrospective study at two large hospitals, 512 patients with borderline and positive anti-HEV-IgM and 94 patients with positive HEV-PCR between January 1999 and May 2023 were included.

RESULTS

Detection by anti-HEV-IgM-ELISA led to a positive HEV-PCR in only 17.9 %. Amongst patients with positive HEV-PCR, 61 had underlying immunosuppression and 23 were patients after solid organ transplantation (SOT). All 13 patients with chronic HEV infections were immunosuppressed. Generally, immunosuppression led to higher HEV-RNA concentrations and a higher probability of receiving immediate treatment. However, all fulminant courses with liver failure happened in patients without immunosuppression. Immunocompetent patients showed symptoms more frequently and primarily had higher bilirubin levels indicating more severe liver damage. A risk factor for delayed or failed viral clearance after SOT was the administration of mTOR inhibitors.

CONCLUSIONS

Fulminant HEV infections happen primarily in immunocompetent patients. Nevertheless, immunosuppressed patients bear the risk of undetected, prolonged HEV infections, reflected by the rare occurrence of symptoms.

Utility of hypervariable region in hepatitis E virus for genetic evolution analysis and epidemiological studies

Clinical and experimental studies have advanced our understanding of hepatitis E virus (HEV) infection; however, translating the findings to improve prevention and clinical outcomes remains challenging. Phylogenetic analyses of HEV show inconsistencies due to variations in the nucleotide regions studied. This study examined specific HEV regions to facilitate comprehensive molecular and phylogenetic analyses by examining the complete genome and commonly studied partial genome regions. We compared topological similarities between phylogenetic trees and evaluated evolutionary divergence using base substitutions and pairwise distances. The hypervariable region (HVR) showed the closest topology (Robinson-Foulds, Jaccard Robinson-Foulds and clustering information) to the complete genome and a higher mutation rate, resulting in longer branch lengths and clearer genotypic distinctions. Pairwise analysis revealed greater intra- and intergenotypic diversity in the HVR than in other regions. The higher base substitution rate and longer branch lengths of HVR suggest its key role in genotype evolution. Classifying HEV using HVR instead of the other partial genomic regions can reveal subtypes that more accurately reflect the genetic characteristics of HEV. Future research could focus on HVRs to better compare clinical symptoms and genetic features of HEV.

Effectiveness of Cold Smoking on Inactivating Murine Norovirus in Salami-Like Pork Sausages (Mettwurst), and Hepatitis E Virus and Murine Norovirus in Solution

Hepatitis E virus (HEV) is a zoonotic virus that infects humans when virus-containing pork products are consumed. This study aimed to explore MNV (murine norovirus) and HEV inactivation during cold smoking and ripening/fermentation treatments used for salami-like sausages (mettwurst). MNV inactivation was monitored in culture medium solution and in sausage while being subjected to a salami-like sausage manufacturing process. The inactivation of MNV in the solution was also monitored at room temperature (RT) for four weeks. HEV inactivation was monitored in solution during the cold smoking process and at RT. A TCID50 assay was used to calculate the infectious MNV and HEV titres. MNV survival was modelled using Bayesian inference. MNV load in solution decreased by as much as 4.7 (SD 0.9) log10 TCID50/ml when it was subjected to the cold smoking process. Modelling revealed that 99.999% MNV might be inactivated during the treatment when observed at a level of 95% CI (Bayesian Confidence Interval). On the contrary, MNV load decreased by only 1.8 (0.2) log10 when stored at RT. The low-titre HEV in solution was inactivated (> 1.1 (0.2) log10) when treated, and at RT. However, MNV was resistant in the sausage matrix during the cold smoking process (log10 reduction of 1.9 (0.5) TCID50/ml). Based on modelling, a substantial amount of virus would remain in the product, even when the uncertainty was considered. Hence, viruses, here exemplified by MNV, may not be inactivated from salami-like pork sausages during manufacturing, which poses a risk for consumers in real-life situations.

A Metagenomic Survey of Virological Hazards in Market-Ready Oysters

Viral contamination of bivalve molluscs, such as oysters, is a well-recognized food safety risk. The aim of this study was to assess virological hazards in market-ready oysters on the Dutch market. Non-targeted metagenome analysis was first performed on norovirus spiked-in samples showing linear and sensitive detection of norovirus GI.2 and GII.4 down to 14 and 5 genome copies per reaction, respectively. Subsequently, metagenomic measurements were performed to detect vertebrate viral genomes present in 24 undepurated B-area samples and 144 market-ready oyster samples taken in November up to and including February of the years 2015-2021. Genome sequences from fifteen viral species were identified in market-ready oysters which are associated with infections in humans and were detected above the genomic coverage threshold (5%) applied. Among these, the two genera from the Caliciviridae family, norovirus and sapovirus were detected at high prevalence (44 and 30%). Additionally, adeno-associated dependoparvovirus A and B as well as Aichi virus A and B (ribo)nucleic acids were detected (42, 33, 6, and 11%). Nucleic acids from virus species in oysters included potentially hazardous Picobirnavirus, Anellovirus, and multiple Circoviridae and Genomoviridae species. By integrating metagenome analysis into the monitoring process, researchers, food producers and regulatory bodies can gain valuable insights into the viral communities present in the food chain. This allows for the detection of potential pathogenic hazards at an early stage, providing an opportunity for tailored monitoring programs and targeted interventions to maintain the sanitary quality of the production area and safeguard public health.

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.

Seroprevalence of hepatitis E virus infection in blood donors from Piauí State, Northeast Brazil

A retrospective and cross-sectional study was carried out on blood donors from Piauí State located at Northeastern Brazil to evaluate the prevalence of Hepatitis E Virus (HEV) infection. Serum samples were tested for anti-HEV IgG and IgM using electrochemiluminescence and HEV RNA was tested using real time PCR. A total of 890 individuals were included with median age of 33.4 years and most of them were male and lived at Mid-Northern region of the State. Prevalences of anti-HEV IgG and IgM were 1.35 % and 0.11 %, respectively. None HEV-RNA was detected. This study demonstrated low prevalence of HEV infection in blood donors in this region.

The Prevalence of Enteric Viruses in Bivalve Molluscs in a Farming Area in Liguria, Northwest Italy

Bivalve molluscs are filter-feeding organisms, capable of concentrating pathogenic microorganisms from the surrounding environment, thus contributing to the spread of viral pathogens, which they can transmit to humans, especially if eaten raw or undercooked. Although norovirus (NoV) and the hepatitis A virus (HAV) are considered the most common causes of foodborne infections, in recent years, other viruses with a zoonotic potential have been identified in shellfish, such as the hepatitis E virus (HEV), astrovirus (AsV), and aichi virus (AiV). The aim of the study was to investigate the presence of classical and emerging pathogenic enteric viruses in oysters (Crassostrea gigas) and mussels (Mytilus galloprovincialis) from a mollusc farming area in the northwest of Italy, between April 2022 and March 2023. In the period considered, a total of 168 samples (84 oysters and 84 mussels) were analysed. The prevalence of NoV was highest, with 32.7% (55/168) positive samples, followed by 18.4% (31/168) for AsV and 19.6% (33/168) for AiV. This study revealed, for the first time, the presence of AsV and AiV in molluscs farmed in this sea area. All the samples tested were negative for HAV and HEV. The emergence of new enteric viruses like AiV and AsV in bivalve molluscs underscores the importance of improving surveillance and environmental monitoring methods, particularly in shellfish production areas.

One-Pot Assay Based on CRISPR/Cas13a Technology for HEV RNA Point-of-Care Testing

Hepatitis E virus (HEV) poses a serious threat to both public health and animal food safety, thereby highlighting the demands for rapid, sensitive, and easy-to-use detection. This study aimed to develop a One-Pot assay using CRISPR/Cas13a for detecting HEV RNA, suitable for point-of-care testing (POCT) in resource-limited settings. CRISPR/Cas13a combined with reverse transcription polymerase chain reaction (RT-PCR) and reverse transcription recombinase-aided amplification (RT-RAA) was applied to a One-Pot assay device. Additionally, a large cohort of HEV-infected patient (154) and animal (104) specimens was utilized for validation. The RT-PCR/RT-RAA + CRISPR/Cas13a assays for HEV RNA detection (genotypes: HEV-1, HEV-3, and HEV-4) were established, optimized, and validated, achieving a limit of detection (LoD) of 1 copy/μL and 100% specificity. In the application validation for HEV infection, the positive rates of the RT-PCR + CRISPR and RT-RAA + CRISPR assays were 98.6% and 89.6% for patients, and 96.6% and 88.8% for animals, respectively, which were superior to those of RT-qPCR. Furthermore, sample rapid lysis, reagent lyophilization, and the One-Pot device were integrated to construct a One-Pot assay with an LoD of 102 copies/μL. Despite slight decreases in sensitivity, the One-Pot assay significantly reduces the assay time to 35 min, making it easy to perform, minimizing contamination, and meeting the requirements for screening. We developed a One-Pot assay of HEV RNA using the CRISPR/Cas13a which effectively realizes a POCT test and maximizes the impetus for POCT implementation and shows potential as a valuable tool for detecting and monitoring HEV infection.

Hepatitis E Virus RNA Detection in Liver and Muscle Tissues Sampled from Home Slaughtered Domestic Pigs in Central Italy

Hepatitis E virus is a worldwide emerging foodborne pathogen; raw or undercooked meats and liver pork products can cause infection through the orofecal route. In Central-Southern Italy, small traditional farming method, associated with the possibility of environmental sharing with wild species, can facilitate HEV diffusion and persistence. The aim of this study was to determine HEV genotype and subtype in Marche region from home slaughtered domestic pigs involved in small and traditional food chains. A total of 236 liver and muscle tissues and 6 pooled salami samples were screened. Laboratory workflow started with homogenization, followed by RNA extraction. Nested reverse transcription PCR and qRT-PCR were used to amplify specific parts of overlapping open reading frames belonging to the HEV genome. A total of 42/236 (17.79%) liver and 8/236 (3.39%) diaphragm specimens were positive; none of the pooled salami specimens showed positive HEV signal. The discovered HEV3c presented high nucleotide similarities with ones amplified from wild boar populations hunted in the same province. Extensive farming methods and environmental sharing with wild animal species support cross-infection infections, as observed in the present study. Although salami resulted negative for HEV RNA detection, the effects of food technologies on viral loads remain unclear. Therefore, further scientific investigations coupled with efficacious standardized laboratory procedures will be the next challenge.

Corrigendum to: "High prevalence of hepatitis E and rat hepatitis E viruses in wastewater in Gothenburg, Sweden" [One Health, volume 19, article number 100882]

[This corrects the article DOI: 10.1016/j.onehlt.2024.100882.].

Emerging zooanthroponotic risks: Detection of the human norovirus GII.4 Sydney[P31] strain in a domestic dog in Brazil

Recent increases in zoonotic diseases underscore the integration of companion animals into urban environments, posing complex transmission risks and highlighting the necessity of One Health approaches. Respiratory and enteric viruses have been consistently linked to interspecies transmission between humans and animals. This study aimed to assess the circulation of human noroviruses (NoV), human adenoviruses (HAdV), enteroviruses (EV), parechoviruses (PeV-A), human bocaviruses (HBoV), hepatitis A (HAV) and E viruses (HEV), Influenza A and B viruses (Flu A/B), respiratory syncytial virus (RSV), and SARS-CoV-2 in domestic dogs and cats in Brazil to understand potential zooanthroponosis risks. Between 2012 and 2021, 600 fecal samples from dogs and cats (516 and 84, respectively) were collected at small animal clinics in São Paulo state, Brazil. The specimens underwent in-house qPCR screening for HBoV and HAdV, while EV, PeV-A, NoV, and HEV were tested using in-house RT-qPCR. SARS-CoV-2, Flu A/B, and RSV were investigated with a commercial RT-qPCR kit assay. HAV detection utilized conventional nested (RT)-PCR. Positive samples were sequenced for molecular characterization and phylogenetic analysis. NoV was detected in 0.2 % (1/600) of the animals, while all other investigated viruses tested negative. The NoV-positive sample, collected in 2012 from a pet dog, was identified as genotype GII.4_Sydney[P31]. The Dog/BRA/2012/GII.4_Sydney[P31]/IAL-M21 strain exhibited a close genetic relationship to Brazilian human and environmental NoV GII.4_Sydney[P31] strains, with 98.1-99.2 % nucleotide similarity in ORF1 and 99.2-99.6 % in ORF2 sequences, suggesting interspecies transmission. Pet dogs are frequently exposed to human fecal-borne viruses, highlighting the potential for zooanthroponotic transmission due to their close interaction with humans in shared environments. There is an urgent need to enhance surveillance studies in companion animals to better understand the implications of detecting human NoV strains in pets, as NoV could potentially act as a reverse zoonotic disease in households, animal hospitals, or shelters worldwide.

Longitudinal serological and virological survey of hepatitis E virus in wild boar (Sus scrofa majori, Maremman wild boar) and fallow deer (Dama dama) populations in a protected area of Central Italy

Hepatitis E virus (HEV) is recognized as an emerging zoonosis. Pigs and wild boars are considered the main reservoirs of zoonotic HEV-3 and HEV-4 genotypes. In Europe, autochthonous human cases of hepatitis E, mainly associated with HEV-3 and consumption of raw or undercooked pig and wild boar liver/meat, have increased over the last decades. From 2016 to 2024, during several hunting seasons, we conducted a molecular and serological longitudinal survey on the circulation of HEV in Maremman wild boar (Italian subspecies/ecotype, Sus scrofa majori) and fallow deer (Dama dama) populations in a protected area in Central Italy. During the study period, 346 livers (256 from wild boar, 90 from fallow deer), 161 serum (127 from wild boar, 34 from fallow deer), and 23 meat juice (11 from wild boar, 12 from fallow deer) samples were collected. Serum and meat juice samples were tested using a commercial ELISA test for the detection of total anti-HEV antibodies. An estimated serological prevalence of 28.3% (39/138) in wild boar and 21.7% (10/46) in fallow deer was found. The 346 liver samples were tested using a HEV Real-Time RT-PCR for the detection of HEV-RNA. Thirty-one wild boar (12%) and four fallow deer (4.4%) livers were found positive. Phylogenetic analysis of 11 partial ORF2 sequences from wild boar confirmed the HEV3 heterogeneity in this species, revealing different strains (3f, 3c) circulating over the years. The detected subtypes are among the most commonly detected in Italy and our strains showed a high correlation with human and wild boar Italian strains. Although the studied area is a fenced natural reserve, the presence of different strains over time suggests the probable virus introduction from the external. Our results confirm fallow deer susceptibility to the infection, and that wild boar could be considered the main wild HEV reservoir. This is also the first study demonstrating the infection in the so-called Italian subspecies/ecotype Maremman wild boar. Moreover, our results corroborate that the consumption of undercooked or raw liver from both wild boar and fallow deer, or the direct contact with these animals, could represent a zoonotic risk.

Zoonoses in dog and cat shelters in North-East Italy: update on emerging, neglected and known zoonotic agents

Introduction

Shelters for stray dogs and cats deserve careful monitoring for zoonotic risk, as they represent a crucial point for prevention and control of infection spread. Data sorting to prioritize zoonotic agents in a geographic area need constant updating, but no regular official programs are ongoing, to allow an efficient risk survey for these animal species. This study aimed to conduct a comprehensive investigation of the prevalence of certain known, potential and emerging zoonoses within the framework of the routine monitoring of dog and cat shelters in North-East Italy.

Methods

A total of 389 cats and 257 dogs housed in public veterinary services shelters and feline colonies were included in the present investigation. The animals originated from the provinces of Padua, Venice, Rovigo, Vicenza, Verona, Trento and Bolzano. Serological, molecular and microbiological diagnostics were implemented to investigate the prevalence of Leptospira sp., Brucella canis, Leishmania infantum, dermatophytes, gastrointestinal parasites, antimicrobial-resistant bacteria, Capnocytophaga sp., Bartonella sp., Norovirus, Rotavirus A, Cowpox virus, Mammalian Orthoreovirus, Hepatitis E virus, SARS-CoV-2 and Influenza A virus.

Results

Data about some known zoonoses (e.g., serological positivity of Leishmania infantum 25% and Leptospira sp. 44.3% in dogs, and Bartonella henselae 70% in cats) resulted aligned with previous research and recent reports, whereas there was a notable occurrence of some potential, emerging and neglected pathogens (e.g., Mammalian Orthoreovirus 0.38% in dogs and 2.83% in cats). For some other agents (e.g., dermatophytes in dogs and in cats) the prevalence resulted lower than expected.

Discussion

The prevention of the zoonotic risk requires a re-examination of the complex interaction between humans, animals, and environment. This is of particular importance in settings like companion animal shelters, which serve as key sites for disease monitoring and zoonotic risk mitigation. The study highlights the need to monitor and prioritize the zoonotic pathogens, to implement and constantly update surveillance and specific training programs for the kennels' operators, and management of epidemiological risks.

Assessment of Hepatitis E Virus RNA Detection in Meat Samples: Optimization of Pre-analytical Conditions

Hepatitis E virus (HEV) is primarily transmitted via the fecal-oral route and is considered an anthropozoonosis. Genotypes with zoonotic potential (mainly HEV-3 and HEV-4) can be transmitted through the consumption of raw or undercooked pork, wild boar, deer meat, or processed products. This study aims to explore methodologies for processing meat samples to establish a protocol for HEV detection in meat. The analysis of pre-analytical conditions involved comparing homogenization with PBS versus TRIzol, comparing tissue disruption methods (ultra-turrax versus mortar and pestle), and assessing nucleic acid extraction techniques (spin columns and magnetic beads) across three types of artificially contaminated meat matrices: pork, salmon (fish-meat), and salami. Each test included a process control virus (PP7) and an HEV transcript. Molecular detection was performed via RT-qPCR. Results indicated that TRIzol provided better recovery rates for homogenization, while spin columns were the most effective option for RNA extraction. Both the ultra-turrax homogenizer and the mortar-pestle methods were effective for pork and fish-meat homogenization, while the use of the UT yielded superior results for salami. HEV recovery rates were 36.7%, 26.3%, and 34.1% for salami, salmon, and pork meat, respectively. In conclusion, we reached a simple and reliable protocol for the detection of RNA-HEV from three meat matrices. This method, which includes homogenization with TRIzol, mechanical tissue disruption, and RNA extraction using spin columns followed by real-time PCR, can be applied in future studies to evaluate HEV prevalence in food sources and contribute to the discussion about HEV detection methodologies.

Prevalence of hepatitis A and E viruses in wastewater in Asian countries

Hepatitis A and E viruses (HAV and HEV, respectively) remain a significant global health concern despite advancements in healthcare and vaccination programs. Regular monitoring and vaccine efficacy of HAV are still lacking in different countries. This study aimed to investigate HAV and HEV prevalence in developed, developing, and least-developed Asian countries using wastewater as a surveillance tool. A total of 232 untreated wastewater samples were collected from six wastewater treatment plants, a sewage treatment plant, or an open drainage in six countries [Nepal (n = 51), Indonesia (n = 37), Thailand (n = 30), Vietnam (n = 27), the Philippines (n = 17), and Japan (n = 70)] between April and October 2022. Viruses in wastewater were concentrated by simple centrifugation or polyethylene glycol precipitation method, followed by viral RNA extraction and reverse transcription-quantitative polymerase chain reaction. HAV and HEV RNA were detected in the samples from Nepal (51 % for HAV and 2 % for HEV), Thailand (3 % for both viruses), and Japan (1 % for HAV and 24 % for HEV). Only HAV RNA was found in 11 % of the samples in Indonesia, whereas only HEV RNA was detected in Vietnam and the Philippines, with a positive ratio of 15 % and 12 %, respectively. These results highlighted the geographic variability in HAV and HEV prevalence, underscoring the need for localized public health strategies to address specific viral hepatitis challenges in each country.

Exploring waterborne viruses in groundwater: Quantification and Virome characterization via passive sampling and targeted enrichment sequencing

Aquifers, which provide drinking water for nearly half the world's population, face significant challenges from microbial contamination, particularly from waterborne viruses such as human adenovirus (HAdV), norovirus (NoV) and enterovirus (EV). This study, conducted as part of the UPWATER project, investigates the sources of urban groundwater contamination using viral passive sampling (VPS) and target enrichment sequencing (TES). We assessed the abundance of eight viral pathogens (HAdV, EV, NoV genogroup I and II, rotavirus, influenza A virus, hepatitis E virus and SARS-CoV-2) and investigated the virome diversity of groundwater in the aquifer of the Besòs River Delta in Catalonia. Over a period of 7 months, we collected 114 samples from the aquifer using nylon and nitrocellulose membranes to adsorb viruses over a 10-day period. Human faecal contamination was detected in nearly 50 % of the groundwater samples, with mean HAdV total counts ranging from 1.23E+02 to 3.66E+03 GC, and occasional detections of EV and NoV GI and GII. In addition, deep sequencing revealed a diverse virome in the aquifer, with detection of human pathogens, including adenovirus, astrovirus, calicivirus, enterovirus, herpesvirus, papillomavirus and rotavirus. Time-integrated sampling using VPS increases the likelihood of virus detection and, when combined with TES, can provide a deeper understanding of virus prevalence in this important water compartment. This approach is expected to streamline long-term monitoring efforts and enable small communities or water managers with limited resources to effectively manage their groundwater reservoirs.

Foodborne Pathogens Across Different Food Matrices in Sicily (Southern Italy)

Foodborne diseases result from the consumption of foods contaminated with pathogens or their toxins and represent a serious public health problem worldwide. This study aimed to assess the presence of Rotavirus (RoV), Adenovirus (AdV), Norovirus (NoV), Hepatitis A and Hepatitis E viruses (HAV and HEV, respectively), Toxoplasma gondii, Coxiella burnetii and Leptospira spp. across various food matrices in Sicily. The analysis concerned 504 samples, including mussels, farmed meat, game meat, vegetables and bulk milk. Following appropriate pre-treatment, acid nucleic extraction was carried out and amplification of pathogen nucleic acids was carried out by molecular methods. The mussels tested positive for NoVs (3/51, 5.9%) and farm meat resulted positive for T. gondii (1/34, 2.9%). The game offal samples tested positive for HEV, which was detected in 17 out of 222 samples (7.7%), and T. gondii (18/318, 5.7%) and Leptospira spp. (2/318, 0.6%). The milk samples tested positive for C. burnetii (15/85, 17.6%), T. gondii (2/85, 2.4%) and Leptospira spp. (1/85, 1.2%). This study highlights the variability in the risk of contamination of different food matrices, confirming the importance of vigilance in the consumption of potentially contaminated food products.

Phosphorylation of Ser711 residue in the hypervariable region of zoonotic genotype 3 hepatitis E virus is important for virus replication

Hepatitis E virus (HEV) is distinct from other hepatotropic viruses because it is zoonotic. HEV-1 and HEV-2 exclusively infect humans, whereas HEV-3 and HEV-4 are zoonotic. However, the viral and/or host factors responsible for cross-species HEV transmission remain elusive. The hypervariable region (HVR) in HEV is extremely heterogenetic and is implicated in HEV adaptation. Here, we investigated the potential role of Serine phosphorylation in the HVR in HEV replication. We first analyzed HVR sequences across different HEV genotypes and identified a unique region at the N-terminus of the HVR, which is variable in the human-exclusive HEV genotypes but relatively conserved in zoonotic HEV genotypes. Using predictive tools, we identified four potential phosphorylation sites that are highly conserved in zoonotic HEV-3 and HEV-4 genomes but absent in human-exclusive HEV-1 strains. To explore the functional significance of these putative phosphorylation sites, we introduced mutations into the HEV-3 infectious clone and indicator replicon, replacing each Serine residue individually with alanine or aspartic acid, and assessed the impact of these substitutions on HEV-3 replication. We found that the phospho-blatant S711A mutant significantly reduced virus replication, whereas the phospho-mimetic S711D mutant modestly reduced virus replication. Conversely, mutations in the other three Serine residues did not significantly affect HEV-3 replication. Furthermore, we demonstrated that Ser711 phosphorylation did not alter host cell tropism of zoonotic HEV-3. In conclusion, our results showed that potential phosphorylation of the Ser711 residue significantly affects HEV-3 replication in vitro, providing new insights into the potential mechanisms of zoonotic HEV transmission.IMPORTANCEHEV is an important zoonotic pathogen, causing both acute and chronic hepatitis E and extrahepatic manifestation of diseases, such as neurological sequelae. The zoonotic HEV-3 is linked to chronic infection and neurological diseases. The specific viral and/or host factors facilitating cross-species HEV infection are unknown. The intrinsically disordered HVR in ORF1 is crucial for viral fitness and adaptation, both in vitro and in vivo. We hypothesized that phosphorylation of Serine residues in the HVR of zoonotic HEV by unknown host cellular kinases is associated with cross-species HEV transmission. In this study, we identified a conserved region within the HVR of zoonotic HEV strains but absent in the human-exclusive HEV-1 and HEV-2. We elucidated the important role of phosphorylation at the Ser711 residue in zoonotic HEV-3 replication, without altering the host cell tropism. These findings contribute to our understanding the mechanisms of cross-species HEV transmission.

Acute Hepatitis Related to Hepatitis E Virus Genotype 3f Infection in Brazil

The hepatitis E virus (HEV) is an important causative agent of acute hepatitis (AH). Despite reports of human infection in Brazil, the investigation is not routinely conducted, even in cases of elevated liver enzymes. This study evaluated two groups: group 1-patients with acute hepatitis A (n = 44); group 2-patients with nonA-C AH (n = 47). They were tested by enzyme immunoassay for anti-HEV IgM/IgG and real-time PCR for HEV RNA detection. The positive sample for HEV RNA was submitted for sequencing. The seroprevalence of anti-HEV IgM and IgG in group 1 was 4% (2/44) and 14.5% (7/44), respectively. Viral RNA was not detected in any sample. In group 2, the anti-HEV IgM positivity was 4.3% (2/47), and IgG 14.9% (7/47). RNA was detectable in one case, which presented a viral load of 222.4 IU/μL and positive anti-HEV IgM/IgG. In the phylogenetic analysis, the genotype identified was HEV-3f. These results indicate that HEV infection should be considered a possible diagnosis in cases of non-A-C AH. The patient identified with acute hepatitis E had recently traveled to the Northeast region of Brazil (Garanhuns city in Pernambuco state), where there are reports of high HEV seroprevalence among pigs. The close phylogenetic relationship observed between the sequence characterized in this study and strains isolated from pigs in nearby cities where the patient went suggested a possible zoonotic transmission in this region. This study highlights the importance of expanding studies and improving surveillance to understand better and manage HEV infections nationwide.

Glucose and glutamine drive hepatitis E virus replication

Viruses have undergone evolutionary adaptations to tune their utilization of carbon sources, enabling them to extract specific cellular substrates necessary for their replication. The lack of a reliable cell culture system and a small-animal model has hampered our understanding of the molecular mechanism of replication of hepatitis E virus (HEV) genotype 1. Our recent identification of a replicative ensemble of mutant HEV RNA libraries has allowed us to study the metabolic prerequisites for HEV replication. Initial assessments revealed increased glucose and glutamine utilization during HEV replication. Inhibition of glycolysis and glycolysis + glutaminolysis reduced the levels of HEV replication to similar levels. An integrated analysis of protein-metabolite pathways suggests that HEV replication markedly alters glycolysis, the TCA cycle, and glutamine-associated metabolic pathways. Cells supporting HEV replication showed a requirement for fructose-6-phosphate and glutamine utilization through the hexosamine biosynthetic pathway (HBP), stimulating HSP70 expression to facilitate virus replication. Observations of mannose utilization and glutamine dependence suggest a crucial role of the HBP in supporting HEV replication. Inhibition of glycolysis and HSP70 activity or knockdown of glutamine fructose-6-phosphate amidotransferase expression led to a substantial reduction in HEV RNA and ORF2 expression accompanied by a significant decrease in HSP70 levels. This study demonstrates that glucose and glutamine play critical roles in facilitating HEV replication.

Strain- and Subtype-Specific Replication of Genotype 3 Hepatitis E Viruses in Mongolian Gerbils

Since Mongolian gerbils are broadly susceptible to hepatitis E virus (HEV), including genotypes 1, 4, 5, and 8 (HEV-1, HEV-5, HEV-5, and HEV-8) and rat HEV, they are a useful small animal model for HEV. However, we have observed that the subtypes HEV-3k and HEV-3ra in genotype 3 HEV (HEV-3) were not infected efficiently in the gerbils. A small-animal model for HEV-3 is also needed since HEV-3 is responsible for major zoonotic HEV infections. To investigate whether gerbils can be used as animal models for other subtypes of HEV-3, we injected gerbils with five HEV-3 subtypes (HEV-3b, -3e, -3f, -3k, and -3ra) and compared the infectivity of the subtypes. We detected viral RNA in the gerbils' feces. High titers of anti-HEV IgG antibodies in serum were induced in all HEV-3b/ch-, HEV-3f-, and HEV-3e-injected gerbils. Especially, the HEV-3e-injected animals released high levels of viruses into their feces for an extended period. The virus replication was limited in the HEV-3b/wb-injected and HEV-3k-injected groups. Although viral RNA was detected in HEV-3ra-injected gerbils, the copy numbers in fecal specimens were low; no antibodies were detected in the sera. These results indicate that although HEV-3's infectivity in gerbils depends on the subtype and strain, Mongolian gerbils have potential as a small-animal model for HEV-3. A further comparison of HEV-3e with different genotype strains (HEV-4i and HEV-5) and different genera (rat HEV) revealed different ALT elevations among the strains, and liver damage occurred in HEV-4i- and HEV-5-infected but not HEV-3e- or rat HEV-infected gerbils, demonstrating variable pathogenicity across HEVs from different genera and genotypes in Mongolian gerbils. HEV-4i- and HEV-5-infected Mongolian gerbils might be candidate animal models to examine HEV's pathogenicity.

Protocol for detection of pathogenic enteric RNA viruses by regular monitoring of environmental samples from wastewater treatment plants using droplet digital PCR

BACKGROUND

The present comprehensive protocol is focused on the detection of pathogenic enteric RNA viruses, explicitly focusing on norovirus genogroup Ⅱ (GⅡ), astrovirus, rotavirus, Aichi virus, sapovirus, hepatitis A and E viruses in wastewater treatment plants through droplet digital PCR (ddPCR). Enteric viruses are of significant public health concern, as they are the leading cause of diseases like gastroenteritis. Regular monitoring of environmental samples, particularly from wastewater treatment plants, is crucial for early detection and control of these viruses. This research aims to improve the understanding of the prevalence and dynamics of enteric viruses in urban India and will serve as a model for similar studies in other regions. Our protocol's objective is to establish a novel ddPCR-based methodology for the detection and molecular characterization of enteric viruses present in wastewater samples sourced from Bhopal, India. Our assay is capable of accurately quantifying virus concentrations without standard curves, minimizing extensive optimization, and enhancing sensitivity and precision, especially for low-abundance targets.

METHODS

The study involves fortnightly collecting and analyzing samples from nine wastewater treatment plants over two years, ensuring comprehensive coverage and consistent data. Our study innovatively applies ddPCR to simultaneously detect and quantify enteric viruses in wastewater, a more advanced technique. Additionally, we will employ next-generation sequencing for detailed viral genome identification in samples tested positive for pathogenic viruses.

CONCLUSION

This study will aid in understanding these viruses' genetic diversity and mutation rates, which is crucial for developing tailored intervention strategies. The findings will be instrumental in shaping public health responses and improving epidemiological surveillance, especially in localities heaving sewage networks.

The 2023 South Sudanese outbreak of Hepatitis E emphasizes ongoing circulation of genotype 1 in North, Central, and East Africa

In April 2023, an outbreak of acute hepatitis was reported amongst internally displaced persons in the Nazareth community of South Sudan. IgM serology-based screening suggested the likely etiologic agent to be Hepatitis E virus (HEV). In this study, plasma specimens collected from anti-HEV IgM-positive cases were subjected to additional RT-qPCR testing and sequencing of extracted nucleic acids, resulting in the recovery of five full and eight partial HEV genomes. Maximum likelihood phylogenetic reconstruction confirmed the genomes belong to HEV genotype 1. Using distance-based methods, we show that genotype 1 is best split into three sub-genotypes instead of the previously proposed seven, and that these sub-genotypes are geographically restricted. The South Sudanese sequences confidently cluster within sub-genotype 1e, endemic to northeast, central, and east Africa. Bayesian Inference of phylogeny incorporating sampling dates shows that this new outbreak is not directly descended from other recent local outbreaks for which sequence data is available. However, the analysis suggests that sub-genotype 1e has been consistently and cryptically circulating locally for at least the past half century and that the known outbreaks are often not directly descended from one another. The ongoing presence of HEV, combined with poor sanitation and hygiene in the conflict-affected areas in the region, place vulnerable populations at risk for infection and its more serious effects, including progression to fulminant hepatitis.

Hepatitis E virus in wild and domestic rabbits from Portugal: a combined molecular and longitudinal serological study

Hepatitis E virus (HEV), species Paslahepevirus balayani, poses a global public health threat, especially in developing countries, by causing acute enterically transmitted hepatitis. HEV infects various mammalian hosts and belongs to the genus Paslahepevirus in the family Hepeviridae. While swine are recognized as the main hosts of HEV, rabbits, which can also be affected by swine HEV-3 related strains, serve as the primary reservoir for the distinct emerging and zoonotic HEV-3ra subtype. In Portugal, where the European wild rabbit is abundant, their role in HEV epidemiology remains unclear. The primary aim of the present research was to evaluate the circulation and the potential for HEV infection within these species. This study employed a molecular and longitudinal serological approach to investigate HEV in Portuguese rabbits. Among the 205 wild rabbits tested, a seroprevalence of 2.44% (95% CI: 0.80-5.60) was found, with no significant associations with age, sex, localization, or sampling dates. Seropositive animals were found in the south and center regions of the country. HEV RNA was not detected in 120 fecal samples, suggesting a natural, low level, and widespread viral circulation. The study underscores the need for further research to comprehend HEV dynamics in these species, which is crucial for assessing potential transmission risks to humans.

Colon-derived Caco-2 cells support replication of hepatitis E virus genotype 1 strain Sar55 generated by reverse genetics

The hepatitis E virus (HEV) is infecting over 20 million people annually with a high morbidity especially in pregnant women and immune-suppressed individuals. While HEV genotype 1 (HEV-1) infects only humans, genotype 3 (HEV-3) is zoonotic and commonly transmitted from infected animals to humans. Whereas a few reverse genetics systems enabling targeted genome manipulations exist for HEV-3, those for HEV-1 are still very limited, mainly because of inefficient cell culture replication. Here, the generation of HEV-1 strain Sar55 and HEV-3 strain 47832mc by transfecting in vitro-transcribed and capped virus genomes into different cell lines was attempted. Culture supernatants of colon-derived colorectal adenocarcinoma cell line Caco-2 contained HEV-1 and HEV-3 capable of infecting Caco-2 cells. Density gradient centrifugation analyses of culture supernatants confirmed that HEV-1 particles were quasi-enveloped in analogy to HEV-3 and that non-virion-associated capsid protein was secreted from cells. Following transfection or infection of Caco-2 cells, HEV-1 consistently reached higher titers than HEV-3 in culture supernatants, but HEV-1 generated by transfection of Caco-2 cells was unable to efficiently infect hepatoma cell lines PLC/PRF/5 or HuH7-Lunet BLR. Taken together, our results indicate that HEV-1 is able to exert a complete replication cycle in Caco-2 cells. An efficient cell culture system for this genotype will be useful for studying species tropism, but further research is required to determine the significance of HEV-1 replication in colon-derived cells.

Water-Based Epidemiological Investigation of Hepatitis E Virus in South Africa

Hepatitis E virus (HEV) is an emerging zoonotic pathogen that exhibits great host diversity. The primary means of transmission of the virus in low- and middle-income countries is contaminated water, often due to a lack of access to proper sanitation, which leads to faecal contamination of water sources. Environmental surveillance is an important tool that can be used to monitor virus circulation and as an early warning system for outbreaks. This study was conducted to determine the prevalence and genetic diversity of HEV in wastewater, surface water (rivers and standpipe/ablution water), and effluent from a piggery in South Africa. A total of 536 water samples were screened for HEV using real-time reverse transcription-polymerase chain reaction. Overall, 21.8% (117/536) of the wastewater, river, and ablution water samples tested positive for HEV, whereas 74.4% (29/39) of the samples from the piggery tested positive. Genotyping revealed sequences belonging to HEV genotypes 3 (98%, 53/54) and 4 (2%, 1/54), with subtypes 3c, 3f, and 4b being identified.

An Immunocompetent Mongolian Gerbil Model for Hepatitis E Virus Genotype 1 Infection

BACKGROUND & AIMS

Hepatitis E virus (HEV), primarily genotype 1 (HEV-1), causes approximately 20.1 million infections, 44,000 deaths, and 3000 stillbirths annually. Current evidence indicates that HEV-1 is only transmitted in humans. Here, we evaluated whether Mongolian gerbils can serve as animal models for HEV-1 infection.

METHODS

Mongolian gerbils were used for HEV-1 and hepatitis E virus genotype 3 infection experiments. HEV infection parameters, including detection of HEV RNA and HEV antigen, liver function assessment, and histopathology, were evaluated.

RESULTS

We adapted a clinical isolate of HEV-1 for Mongolian gerbils by serial passaging in feces of aged male gerbils. The gerbil-adapted strain obtained at passage 3 induced a robust, acute HEV infection, characterized by stable fecal virus shedding, elevated liver enzymes, histopathologic changes in the liver, and seroconversion to anti-HEV. An infectious complementary DNA clone of the adapted virus was generated. HEV-1-infected pregnant gerbils showed a high rate of maternal mortality and vertical transmission. HEV RNA or antigens were detected in the liver, kidney, intestine, placenta, testis, and fetus liver. Liver and placental transcriptomic analyses indicated activation of host immunity. Tacrolimus prolonged HEV-1 infection, whereas ribavirin cleared infection. The protective efficacy of a licensed HEV vaccine was validated using this model.

CONCLUSIONS

HEV-1 efficiently infected Mongolian gerbils. This HEV-1 infection model will be valuable for investigating hepatitis E immunopathogenesis and evaluating vaccines and antivirals against HEV.

Integrated hepatitis e virus monitoring in central Argentina: a six-year analysis of clinical surveillance and wastewater-based epidemiology

Wastewater-based epidemiology (WBE) has gained prominence worldwide as a powerful tool in public health. This study aimed to monitor the circulation of Hepatitis E Virus (HEV) from wastewater samples collected during a six-year period and compare these results with clinical surveillance in the central region of Argentina. From 2017 to 2022, 1008 raw wastewater samples were analyzed, including four wastewater treatment plants from four cities (n=319), and 7 local neighborhood collector sewers in Córdoba city (n=689). Serum and/or stool samples from patients suspected of HEV infection were also analyzed (n=48). HEV molecular detection and viral load quantification were performed by real time RT-qPCR, and genetic characterization by two RT-Nested PCRs (targeting partial ORF-1 and ORF-2 genomic regions), sequencing and phylogenetic analysis. Fifty-three (5.3%) wastewater samples were RNA-HEV positive by real time RT-qPCR, with variations according to the location and year (0.0% - 21.6%). Out of these, ORF-2 genomic region was amplified in 20 samples (37.7%) and ORF-1 partial region in 12 (22.6%), and eighteen sequences were obtained. Throughout the study period, two (4.2%) HEV confirmed infections were reported, and one sequence was obtained. Phylogenetic analyses for both genomic regions showed that all the isolates were genotype HEV-3 clade abchijklm. Our study detected HEV in wastewater over a six-year period, despite a low number of clinical cases, emphasizing WBE as a valuable tool that complements clinical surveillance, by detecting pathogens' presence; identifying their transmission, circulation dynamics and excretion hotspots; and revealing changes in their genomic diversity.

Combining RNA Interference and RIG-I Activation to Inhibit Hepatitis E Virus Replication

Hepatitis E virus (HEV) poses a significant global health threat, with an estimated 20 million infections occurring annually. Despite being a self-limiting illness, in most cases, HEV infection can lead to severe outcomes, particularly in pregnant women and individuals with pre-existing liver disease. In the absence of specific antiviral treatments, the exploration of RNAi interference (RNAi) as a targeted strategy provides valuable insights for urgently needed therapeutic interventions against Hepatitis E. We designed small interfering RNAs (siRNAs) against HEV, which target the helicase domain and the open reading frame 3 (ORF3). These target regions will reduce the risk of viral escape through mutations, as they belong to the most conserved regions in the HEV genome. The siRNAs targeting the ORF3 efficiently inhibited viral replication in A549 cells after HEV infection. Importantly, the siRNA was also highly effective at inhibiting HEV in the persistently infected A549 cell line, which provides a suitable model for chronic infection in patients. Furthermore, we showed that a 5' triphosphate modification on the siRNA sense strand activates the RIG-I receptor, a cytoplasmic pattern recognition receptor that recognizes viral RNA. Upon activation, RIG-I triggers a signaling cascade, effectively suppressing HEV replication. This dual-action strategy, combining the activation of the adaptive immune response and the inherent RNAi pathway, inhibits HEV replication successfully and may lead to the development of new therapies.

A Broad-specificity Neutralizing Nanobody against Hepatitis E Virus Capsid Protein

Hepatitis E virus (HEV) is a worldwide zoonotic and public health concern. The study of HEV biology is helpful for designing viral vaccines and drugs. Nanobodies have recently been considered appealing materials for viral biological research. In this study, a Bactrian camel was immunized with capsid proteins from different genotypes (1, 3, 4, and avian) of HEV. Then, a phage library (6.3 × 108 individual clones) was constructed using peripheral blood lymphocytes from the immunized camel, and 12 nanobodies against the truncated capsid protein of genotype 3 HEV (g3-p239) were screened. g3-p239-Nb55 can cross-react with different genotypes of HEV and block Kernow-C1/P6 HEV from infecting HepG2/C3A cells. To our knowledge, the epitope recognized by g3-p239-Nb55 was determined to be a novel conformational epitope located on the surface of viral particles and highly conserved among different mammalian HEV isolates. Next, to increase the affinity and half-life of the nanobody, it was displayed on the surface of ferritin, which can self-assemble into a 24-subunit nanocage, namely, fenobody-55. The affinities of fenobody-55 to g3-p239 were ∼20 times greater than those of g3-p239-Nb55. In addition, the half-life of fenobody-55 was nine times greater than that of g3-p239-Nb55. G3-p239-Nb55 and fenobody-55 can block p239 attachment and Kernow-C1/P6 infection of HepG2/C3A cells. Fenobody-55 can completely neutralize HEV infection in rabbits when it is preincubated with nonenveloped HEV particles. Our study reported a case in which a nanobody neutralized HEV infection by preincubation, identified a (to our knowledge) novel and conserved conformational epitope of HEV, and provided new material for researching HEV biology.

Detection of Hepatitis E Virus in Game Meat (Wild Boar) Supply Chain in Umbria Region, Central Italy

Consumption of raw or undercooked wild boar (WB) meat is considered an important risk factor for hepatitis E virus (HEV) infection in humans. The possibility of HEV contamination during the slaughtering practices may pose an additional risk. Based on these assumptions, we evaluated HEV contamination of WB meat hunted in Umbria (central Italy) during the 2022-2023 hunting season by real-time RT-PCR. Herein, we show that 10.8% of livers from slaughtered WB were positive for HEV RNA, thus providing an estimate of HEV infection in WB in the Umbria region. Then, by evaluating paired liver-muscle samples from both HEV-positive and HEV-negative animals, we found evidence of muscle HEV contamination in 33% and 14% of cases, respectively. This is the first report on the detection of HEV in WB meat in Umbria, an Italian region with diffuse WB hunting and consumption. The evidence of contamination provided by our study underscores the importance of adopting good hygienic practices in the processing stages of hunted WB carcasses to significantly reduce meat contamination and the risk posed for the final consumer.

The AP-1 adaptor complex is essential for intracellular trafficking of the ORF2 capsid protein and assembly of Hepatitis E virus

Although the Hepatitis E virus (HEV) is an emerging global health burden, little is known about its interaction with the host cell. HEV genome encodes three proteins including the ORF2 capsid protein that is produced in different forms, the ORF2i protein which is the structural component of viral particles, and the ORF2g/c proteins which are massively secreted but are not associated with infectious material. We recently demonstrated that the endocytic recycling compartment (ERC) is hijacked by HEV to serve as a viral factory. However, host determinants involved in the subcellular shuttling of viral proteins to viral factories are unknown. Here, we demonstrate that the AP-1 adaptor complex plays a pivotal role in the targeting of ORF2i protein to viral factories. This complex belongs to the family of adaptor proteins that are involved in vesicular transport between the trans-Golgi network and early/recycling endosomes. An interplay between the AP-1 complex and viral protein(s) has been described for several viral lifecycles. In the present study, we demonstrated that the ORF2i protein colocalizes and interacts with the AP-1 adaptor complex in HEV-producing or infected cells. We showed that silencing or drug-inhibition of the AP-1 complex prevents ORF2i protein localization in viral factories and reduces viral production in hepatocytes. Modeling of the ORF2i/AP-1 complex also revealed that the S domain of ORF2i likely interacts with the σ1 subunit of AP-1 complex. Hence, our study identified for the first time a host factor involved in addressing HEV proteins (i.e. ORF2i protein) to viral factories.

Persistence of hepatitis E virus (HEV) subtypes 3c and 3e: Long-term cold storage and heat treatments

Hepatitis E virus (HEV) is the causative agent of foodborne infections occurring in high income countries mainly by consumption of undercooked and raw pork products. The virus is zoonotic with pigs and wild boars as the main reservoirs. Several studies proved the presence of HEV-RNA in pork liver sausages, pâté and other pork by-products. However, the detection of HEV nucleic acids does not necessary correspond to infectious virus and information on the persistence of the virus in the food is still limited. To which extent and how long the virus can survive after conventional industrial and home-made conservation and cooking procedures is largely unknown. In the present study, we investigated the persistence of two subtypes of HEV-3, by measuring the viral RNA on cell supernatant of infected A549 cells, after long-term storage at +4 °C and -20 °C and after heating for short or long-time span. Results confirmed that either low temperature storage (+4 °C) or freezing (-20 °C) do not influence the survival of the virus, and only a moderate reduction of presence of its RNA after 12 weeks at +4 °C was observed. To the other side, heating at 56 °C for long time (1 h) or at higher temperatures (>65 °C) for shorter time inactivated the virus successfully.

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.

Application of Methods Detecting Xenotransplantation-Relevant Viruses for Screening German Slaughterhouse Pigs

Detection methods have been developed to prevent transmission of zoonotic or xenozoonotic porcine viruses after transplantation of pig organs or cells to the recipient (xenotransplantation). Eleven xenotransplantation-relevant viruses, including porcine cytomegalovirus, porcine roseolovirus (PCMV/PRV), porcine lymphotropic herpesviruses -1, -2, -3 (PLHV-1, 2, 3), porcine parvovirus (PPV), porcine circovirus 2, 3, 4 (PCV2, 3, 4), hepatitis E virus genotype 3 (HEV3), porcine endogenous retrovirus-C (PERV-C), and recombinant PERV-A/C have been selected. In the past, several pig breeds, minipigs, and genetically modified pigs generated for xenotransplantation had been analyzed using these methods. Here, spleen, liver, and blood samples from 10 German slaughterhouse pigs were screened using both PCR-based and immunological assays. Five viruses: PCMV/PRV, PLHV-1, PLHV-3, and PERV-C, were found in all animals, and PCV3 in one animal. Some animals were latently infected with PCMV/PRV, as only virus-specific antibodies were detected. Others were also PCR positive in the spleen and/or liver, indicative of an ongoing infection. These results provide important information on the viruses that infect German slaughterhouse pigs, and together with the results of previous studies, they reveal that the methods and test strategies efficiently work under field conditions.

Cross-species transmission and histopathological variation in specific-pathogen-free minipigs infected with different hepatitis E virus strains

Hepatitis E virus (HEV) is a major cause of viral hepatitis worldwide. Pigs are the natural host of HEV genotype 3 and the main reservoir of HEV. As the host range of HEV genotype 3 expands, the possibility that HEV from various species can be transmitted to humans via pigs is increasing. We investigated the potential cross-species transmission of HEV by infecting minipigs with swine HEV (swHEV), rabbit HEV (rbHEV), and human HEV (huHEV) and examining their histopathological characteristics and distribution in various organs. Fifteen specific-pathogen-free Yucatan minipigs were infected with swHEV, rbHEV, huHEV, or a mock control. In the present study, we analysed faecal shedding, viremia, and serological parameters over a seven-week period. Our results indicated that swHEV exhibited more robust shedding and viremia than non-swHEVs. Only swHEV affected the serological parameters, suggesting strain-specific differences. Histopathological examination revealed distinct patterns in the liver, pancreas, intestine, and lymphoid tissues after infection with each HEV strain. Notably, all three HEVs induced histopathological changes in the pancreas, supporting the association of HEVs with acute pancreatitis. Our results also identified skeletal muscle as a site of HEV antigen presence, suggesting a potential link to myositis. In conclusion, this study provides valuable insights into the infection dynamics of different HEV strains in minipigs, emphasizing the strain-specific variations in virological, serological, and histological parameters. The observed differences in infection kinetics and tissue tropism will contribute to our understanding of HEV pathogenesis and the potential for cross-species transmission.

Reconstruction of the historic time course of blood-borne virus contamination of clotting factor concentrates, 1974-1992

Factor VIII and IX clotting factor concentrates manufactured from pooled plasma have been identified as potent sources of virus infection in persons with hemophilia (PWHs) in the 1970s and 1980s. To investigate the range and diversity of viruses over this period, we analysed 24 clotting factor concentrates for several blood-borne viruses. Nucleic acid was extracted from 14 commercially produced clotting factors and 10 from nonremunerated donors, preserved in lyophilized form (expiry dates: 1974-1992). Clotting factors were tested by commercial and in-house quantitative PCRs for blood-borne viruses hepatitis A, B, C and E viruses (HAV, HBV, HCV, HEV), HIV- types 1/2, parvoviruses B19V and PARV4, and human pegiviruses types 1 and 2 (HPgV-1,-2). HCV and HPgV-1 were the most frequently detected viruses (both 14/24 tested) primarily in commercial clotting factors, with frequently extremely high viral loads in the late 1970s-1985 and a diverse range of HCV genotypes. Detection frequencies sharply declined following introduction of virus inactivation. HIV-1, HBV, and HAV were less frequently detected (3/24, 1/24, and 1/24 respectively); none were positive for HEV. Contrastingly, B19V and PARV4 were detected throughout the study period, even after introduction of dry heat treatment, consistent with ongoing documented transmission to PWHs into the early 1990s. While hemophilia treatment is now largely based on recombinant factor VIII/IX in the UK and elsewhere, the comprehensive screen of historical plasma-derived clotting factors reveals extensive exposure of PWHs to blood-borne viruses throughout 1970s-early 1990s, and the epidemiological and manufacturing parameters that influenced clotting factor contamination.