Viral clade is associated with severity of symptomatic genotype 3 hepatitis E virus infections in Belgium, 2010-2018

Prevalence of hepatitis E in Latin America and the Caribbean: A systematic review and meta-analysis

OBJECTIVE

To estimate the prevalence of hepatitis E virus (HEV) infection by the presence of anti-HEV IgG antibodies in Latin America and the Caribbean (LAC).

STUDY DESIGN

Systematic review and meta-analysis.

METHODS

Systematic searches were conducted in the Medline, Lilacs and Embase databases, selecting 81 studies comprising 38,951 individuals in accordance with the PRISMA Statement. Analyses were performed by using the random-effects model. Data analysis considered study cohort and geographic location.

RESULTS

The prevalence of hepatitis E in LAC ranged from 0 % to 36 % and the overall prevalence was 9.0 %, with important heterogeneity (I2 = 97.3 %). Meta-analysis of subgroups showed prevalence of hepatitis E of 9.0 % in the general population, 6.0 % in blood donors, 9.0 % in rural population, 21.0 % in occupational exposure to pigs, 9.0 % in pregnant women, 7.0 % in immunocompromised individuals, 12.0 % in individuals with chronic liver disease and 9.0 % in individuals with acute hepatitis. According to geographic location, the prevalence of hepatitis E was 7.0 % in Argentina, 16.0 % in Bolivia, 7.0 % in Brazil, 17.0 % in Colombia and 24.0 % in Cuba. The generated funnel plot appeared asymmetric, with evidence of bias according to Egger (p = 0.000) and Begg (p = 0.003) tests. In the analysis, which included only studies with a quality score >5, the prevalence of hepatitis E was 8.0 %. When analysing studies with sample sizes greater than 200 and 500, we identified prevalences of 8.0 % and 7.0 %, respectively.

CONCLUSIONS

The information obtained in this review warns about the current consolidated prevalence of hepatitis E in LAC, which can be a tool for planning prevention strategies.

Large-scale HEV genotype 3 outbreak on New Caledonia Island

BACKGROUND AND AIMS

Several symptomatic cases of HEV infections were reported to the New Caledonia Island Public Health Service between August and December 2023. This prompted epidemiological and virological investigations to identify the source of infection.

APPROACH AND RESULTS

HEV RNA was assessed in symptomatic patients, various food items, and pig farms on the Island. HEV strains were characterized by sequencing. A seroprevalence study was also conducted on asymptomatic blood donors before and after the outbreak. One hundred twenty-seven symptomatic cases were reported. Hospitalization was required for 29/127 patients (22.8%). Hospitalized patients presented more frequently with comorbidities, including liver and cardiovascular diseases (80.7% vs. 27%, p < 0.01), and 3 persons died (2.3%). Among the 100 HEV RNA-positive samples received at the French National Reference Centre for HEV, viral sequencing was possible for 76 samples. All strains were identified as HEV genotype 3, and 74/76 strains were grouped together (nucleotide identity: 98%-100%). Full-length sequencing indicated a new HEV-3 subtype within HEV-3 subclade abk. Only genotype 3f strains were detected on the Island's pig farms. No food items tested positive for HEV RNA. The seroprevalence of HEV IgG and IgM in blood donors was 9.2% (9/98) and 0%, respectively, in 2020, rising to 17.3% (17/98) and 2% (2/98) in 2024.

CONCLUSIONS

Although all previous large-scale epidemics in Asia and Africa were associated with HEV-1 or 2, the New Caledonia outbreak was linked to HEV-3. A high number of symptomatic cases were admitted to the hospital, with a case-fatality rate of 2.3%.

HEV-3 subtypes and strains detected in cases of HEV infection in central Italy from 2015 to 2023

PURPOSE

HEV is an emerging pathogen in Europe and was previously shown to be hyperendemic in areas of Abruzzo and Lazio, Central Italy. No systematic analysis of the HEV strains responsible for human infections over several years in Central Italy has previously been reported. Aim of the study was the molecular characterization of HEV from autochthonous hepatitis E cases occurred in Abruzzo and Lazio between 2015 and 2023.

METHODS

Samples from 118 cases collected as part of virological surveillance in Abruzzo and Lazio from 2015 to 2023 were subjected to HEV sequencing and phylogenetic analysis.

RESULTS

The main observed subtype was 3f, followed by 3c and 3e. The annual subtype distribution was quite stable over the observation period, but 3f cases tended to concentrate in winter/early spring whereas 3e cases in summer. Phylogenetic clusters of highly related sequences (a) highlighted unrecognized "point source outbreaks", (b) provided molecular support to temporally and/or geographically linked cases and (c) provided evidence for transmission of identical/highly related strains up to months/years following their first detection.

CONCLUSIONS

The data provide an overview of the HEV strains responsible for human infections over eight years in Central Italy. The observed subtype distribution appears to agree better with the subtype distribution reported in Italy in pigs rather than in geographically matched wild boars, suggesting pig and its derivate food was a more frequent source of infection than wild boar in Abruzzo and Lazio. Molecular characterization is essential to recognize "point source outbreaks" and to monitor HEV circulation.

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.

Inborn errors of type I interferon immunity in patients with symptomatic acute hepatitis E

BACKGROUND AND AIMS

The clinical spectrum of human infection by HEV ranges from asymptomatic to severe acute hepatitis. Furthermore, HEV can cause diverse neurological manifestations, especially Parsonage-Turner syndrome. Here, we used a large-scale human genomic approach to search for genetic determinants of severe clinical presentations of HEV infection.

APPROACH AND RESULTS

We performed whole genome sequencing in 3 groups of study participants with PCR-proven acute HEV infection: (1) 24 patients with symptomatic acute hepatitis E; (2) 12 patients with HEV-associated Parsonage-Turner syndrome; and (3) 16 asymptomatic blood donors (controls). For variant calling and annotation, we used GATK4 best practices followed by Variant Effect Predictor (VEP) and Annovar. For variant classification, we implemented the American College of Medical Genetics and Genomics/Association for Molecular Pathology Bayesian classification framework in R. Variants with a probability of pathogenicity >0.9 were considered damaging. We used all genes with at least 1 damaging variant as input for pathway enrichment analyses.We observed a significant enrichment of type I interferon response pathways in the symptomatic hepatitis group: 10 out of 24 patients carried a damaging variant in one of 9 genes encoding either intracellular viral sensors ( IFIH1 , DDX58 , TLR3 , POLR3B , POLR3C ) or other molecules involved in type I interferon response [interferon regulatory factor 7 ( IRF7 ), MYD88 , OAS3 , GAPDH ]. We did not find any enriched pathway in the Parsonage-Turner syndrome group or in the controls.

CONCLUSIONS

Our results highlight the essential role of type I interferon in preventing symptomatic acute hepatitis E.

Monitoring of hepatitis E virus in wastewater can identify clinically relevant variants

Hepatitis E virus (HEV) is prevalent worldwide and can cause persistent infection with severe morbidity. Antiviral treatment approaches can lead to the emergence of viral variants encoding escape mutations that may impede viral clearance. The frequency of these variants remains unknown in the human population as well as environment due to limited comprehensive data on HEV diversity. In this study, we investigated the HEV prevalence and diversity of circulating variants in environmental samples, that is, wastewater and rivers from North-Rhine Westphalia, Germany. HEV prevalence could be determined with 73% of samples tested positive for viral RNA via qRT-PCR. Using high-throughput sequencing, we were able to assess the overall genetic diversity in these samples and identified the presence of clinically relevant variants associated with drug resistance. In summary, monitoring variants from environmental samples could provide valuable insights into estimating HEV prevalence and identifying circulating variants that can impact treatment outcome.

Molecular Characterization and Phylogenetic Analysis of Hepatitis E Virus (HEV) Strains from Pigs Farmed in Eight European Countries between 2020 and 2022

In high-income countries, the hepatitis E virus (HEV) is considered an emerging threat causing autochthonous acute hepatitis in humans, with an increased number of reported cases over the last 10 years and related increased burden of chronic hepatitis in immunocompromised and transplant patients. Pigs are the main reservoir of the HEV-3 genotype, which is the most common in Europe, and can be transmitted to humans through the consumption of raw and undercooked pork products. Extensive sequencing revealed the existence of several HEV-3 subtypes in both humans and pigs, confirming a broad heterogeneity of the virus, with some subtypes, such as 3e, 3f, and 3c, which are predominant in Europe. In this study, 291 HEV sequences were obtained from pig feces sampled in more than 74 farms located in Austria, Bulgaria, Czech Republic, Germany, Italy, Poland, the United Kingdom, as well as an unknown number of farms in Netherlands. Of the 99 nonidentical sequences (99/291), 90 were assigned to seven established HEV-3 subtypes: 3a, 3c, 3e, 3f, 3g (here named 3g-like), 3i, and 3l (named 3l-like), already described in Europe, while nine sequences of HEV-3 could not be assigned to any existing subtype (here named 3  ∗ ). The 3e subtype was the most common, detected in six out of eight countries, followed by 3f and 3c, which were also present in several countries; 3g-like, 3i, and 3l-like subtypes showed only a limited circulation. The distribution of frequently (3e, 3f, and 3c) and rarely (3g-like, 3i, and 3l-like) detected HEV-3 subtypes in pigs was correlated with their detection rates in human patients in Europe. The results from this study confirm the wide circulation of several HEV-3 strains in European pigs and confirm that sequencing is needed to monitor the different strains and to identify possible zoonotic transmission paths.

A Multifaceted Approach for Evaluating Hepatitis E Virus Infectivity In Vitro: Cell Culture and Innovative Molecular Methods for Integrity Assessment

Hepatitis E virus is a prominent cause of viral hepatitis worldwide. In Western countries, most infections are asymptomatic. However, acute self-limiting hepatitis and chronic cases in immunocompromised individuals can occur. Studying HEV is challenging due to its difficulty to grow in cell culture. Consequently, the detection of the virus mainly relies on RT-qPCR, which cannot differentiate between infectious and non-infectious particles. To overcome this problem, methods assessing viral integrity offer a possible solution to differentiate between intact and damaged viruses. This study aims at optimizing existing HEV cell culture models and RT-qPCR-based assays for selectively detecting intact virions to establish a reliable model for assessing HEV infectivity. In conclusion, these newly developed methods hold promise for enhancing food safety by identifying approaches for inactivating HEV in food processing, thereby increasing food safety measures.

Identification of interferon-stimulated genes with modulated expression during hepatitis E virus infection in pig liver tissues and human HepaRG cells

Introduction

Hepatitis E virus (HEV) is a common cause of enterically transmitted acute hepatitis worldwide. The virus is transmitted by the fecal-oral route via the consumption of contaminated water supplies and is also a zoonotic foodborne pathogen. Swine are the main reservoir of zoonotic HEV. In humans, HEV infection is usually asymptomatic or causes acute hepatitis that is self-limited. However, fulminant hepatic failure and chronic cases of HEV infection can occur in some patients. In contrast, HEV infection in pigs remains asymptomatic, although the virus replicates efficiently, suggesting that swine are able to control the virus pathogenesis. Upon viral infection, IFN is secreted and activates cellular pathways leading to the expression of many IFN-stimulated genes (ISGs). ISGs can restrict the replication of specific viruses and establish an antiviral state within infected and neighboring cells.

Methods

In this study, we used PCR arrays to determine the expression level of up to 168 ISGs and other IFN-related genes in the liver tissues of pigs infected with zoonotic HEV-3c and HEV-3f and in human bipotent liver HepaRG cells persistently infected with HEV-3f.

Results and discussion

The expression of 12 and 25 ISGs was found to be up-regulated in infected swine livers and HepaRG cells, respectively. The expression of CXCL10, IFIT2, MX2, OASL and OAS2 was up-regulated in both species. Increased expression of IFI16 mRNA was also found in swine liver tissues. This study contributes to the identification of potential ISGs that could play a role in the control or persistence of HEV infection.

Clinical characteristics of 1279 patients with hepatitis E in Tianjin

Hepatitis E virus infection is a major cause of acute hepatitis, typically self-limiting but occasionally leading to liver failure. Understanding disease progression factors could inform prevention strategies. This study aimed to analyse the characteristics of a large cohort of hospitalised hepatitis E patients in Tianjin, China, and explore factors influencing their progression to liver failure. A total of 1279 hospitalised patients with hepatitis E were included in this cross-sectional study in Tianjin, China. Student's t-test and the Mann-Whitney U-test were used for comparisons. Multiple logistic regression analysis was used to explore the association. Among these 1279 patients, 107 (8.4%) developed liver failure. Patients with diabetes mellitus (DM) (95% confidence interval [CI] 1.150-2.887, p = 0.011), liver cirrhosis (95% [CI] 2.229-7.224, p < 0.001), and hepatitis B (95% [CI] 1.159-4.512, p = 0.017) were more likely to progress to liver failure. Hepatitis E patients with comorbid DM, liver cirrhosis, or hepatitis B virus co-infection have higher risks of developing liver failure. Hepatitis E vaccination may be recommended for these vulnerable patients to curb disease severity.

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.

Temporal changes in the genotypes of Paslahepevirus balayani in southern Spain and their possible link with changes in pig trade imports

Introduction

Paslahepevirus balayani (HEV) is an endemic zoonotic disease ranked as a major cause of acute hepatitis in Europe. Most infections occurring in Europe are due to the endemic several subtypes of genotype 3, through the consumption of raw or undercooked pork, observing a genotype geographical distribution pattern among countries Because of global changes in the pig and pork trading markets, subtype distribution might vary. We aimed to evaluate the temporal distribution of HEV genotypes in patients from southern Spain with acute hepatitis to determine whether these changes were related to the pig import trade during the study period between 2018 and 2022.

Methods

Prospective longitudinal study including patients with acute hepatitis from southern Spain between 2018 and 2022. HEV RNA and antibodies was tested in all patients. In patients with detectable HEV RNA, genotype was obtained. To determine the number of imported pigs and their origins, we checked the official data from the Spanish statistics on international trade of Spanish Minister of Industry during by country of origin during the same study period.

Results

A total of 659 patients with acute hepatitis were included in the study. Among them, 162 (24.5%) had at least one marker (IgM or RNA) of acute HEV infection. Among the 71 patients with detectable viral RNA, genotypes could be obtained for 58 (81.6%). The most prevalent HEV genotype was 3f (n = 48; 78.6%), showing a decreasing prevalence of over time, from 100% in 2018 to 70.6% in 2022. Since 2021, the emergence of other genotypes has been determined. A significant increase in the number of animals imported was observed since the beginning of the study. Denmark experienced a significant rise, from 0.03% in 2018 of total imports to 10.4% in 2022.

Conclusions

HEV molecular diversity is changing in Spain, could be linked to changes in fattening pig import origin.

Uncovering neglected subtypes and zoonotic transmission of Hepatitis E virus (HEV) in Brazil

Hepatitis E virus (HEV) circulation in humans and swine has been extensively studied in South America over the last two decades. Nevertheless, only 2.1% of reported HEV strains are available as complete genome sequences. Therefore, many clinical, epidemiological, and evolutionary aspects of circulating HEV in the continent still need to be clarified. Here, we conducted a retrospective evolutionary analysis of one human case and six swine HEV strains previously reported in northeastern, southern, and southeastern Brazil. We obtained two complete and four nearly complete genomic sequences. Evolutionary analysis comparing the whole genomic and capsid gene sequences revealed high genetic variability. This included the circulation of at least one unrecognized unique South American subtype. Our results corroborate that sequencing the whole capsid gene could be used as an alternative for HEV subtype assignment in the absence of complete genomic sequences. Moreover, our results substantiate the evidence for zoonotic transmission by comparing a larger genomic fragment recovered from the sample of the autochthonous human hepatitis E case. Further studies should continuously investigate HEV genetic diversity and zoonotic transmission of HEV in South America.

CXCL10 Chemokine: A Critical Player in RNA and DNA Viral Infections

Chemokines constitute a group of small, secreted proteins that regulate leukocyte migration and contribute to their activation. Chemokines are crucial inflammatory mediators that play a key role in managing viral infections, during which the profile of chemokine expression helps shape the immune response and regulate viral clearance, improving clinical outcome. In particular, the chemokine ligand CXCL10 and its receptor CXCR3 were explored in a plethora of RNA and DNA viral infections. In this review, we highlight the expression profile and role of the CXCL10/CXCR3 axis in the host defense against a variety of RNA and DNA viral infections. We also discuss the interactions among viruses and host cells that trigger CXCL10 expression, as well as the signaling cascades induced in CXCR3 positive cells.