Hepatitis E virus genotype 3 diversity, France

Evaluation of an automated platform for the detection of HEV RNA in plasma and stool

INTRODUCTION

We evaluated the performance of the automated Altostar HEV RNA platform for detecting HEV RNA.

METHODS AND RESULTS

Clinical performance was determined by testing 81 plasma samples and 10 fecal samples manually quantified previously with the Realstar RT-PCR assay using the Magnapure instrument for extraction. The assays were concordant for 79/81 plasma samples (97.5%) and 10/10 (100%) fecal samples. The two plasma samples that tested negative with the Altostar assay had a very low HEV RNA concentration (1.6 and 1.4 log10 IU/ml). Quantitative results obtained with the automated platform and the manual workflow were highly correlated (ρ= 0.98, p<0.01). The intra-run and inter-run standard deviation were 0.09 IU/ml and 0.13 IU/ml respectively. The assay was linear from 2 to 6 log IU/ml. The limit of detection determined by Probit analysis with the WHO HEV RNA standard was 7.6 [95% CI: 4.4-52.5] IU/ml.

CONCLUSIONS

The Altostar platform enables highly accurate testing for the detection of HEV RNA in stool and the quantification of HEV RNA in plasma. This allowed us to shorten turnaround times and to save time for the technical staff.

Relevance of Tacrolimus Trough Concentration and Hepatitis E virus Genetic Changes in Kidney Transplant Recipients With Chronic Hepatitis E

Introduction

Hepatitis E virus (HEV) can cause chronic infection (≥3 months) and cirrhosis in immunocompromised patients, especially kidney transplant recipients. Low alanine aminotransferase (ALT) levels and high HEV intrahost diversity have previously been associated with evolution toward chronicity in these patients. We hypothesized that additional clinical and viral factors could be associated with the risk of chronic HEV infection.

Methods

We investigated a series of 27 kidney transplant recipients with HEV infection, including 20 patients with chronic hepatitis E.

Results

High tacrolimus trough concentration at diagnosis was the most relevant marker associated with chronic hepatitis E (9.2 vs. 6.4 ng/ml, P = 0.04). Most HEV genetic changes selected during HEV infection were compartmentalized between plasma and feces.

Conclusion

This compartmentalization highlights the diversity and complexity of HEV replication compartments. Tacrolimus trough concentration at diagnosis of HEV infection could allow an early identification of patients at high risk of chronic hepatitis E and guide treatment initiation.

Molecular identification and genotyping of hepatitis E virus from Southern Punjab, Pakistan

Hepatitis E is a global health concern. Hepatitis E virus (HEV) infection is endemic in Pakistan. HEV has four genotypes: HEV-1 through HEV-4. The genotypes HEV-1 and HEV-2 are associated with infection in humans, especially in countries with poor sanitation. The genotypes HEV-3 and HEV-4 are zoonotic and human infection takes place by consuming undercooked meat or being in contact with animals. The present study was designed to ascertain the presence of HEV in the Southern Punjab region of Pakistan. First, blood samples (n = 50) were collected from patients suspected of infection with the hepatitis E virus from the Multan District. The serum was separated and the samples were initially screened using an HEV IgM-ELISA. Second, the ELISA-positive samples were subjected to PCR and were genetically characterized. For PCR, the RNA extraction and complementary DNA synthesis were done using commercial kits. The HEV ORF2 (Open Reading Frame-2, capsid protein) was amplified using nested PCR targeting a 348 bp segment. The PCR amplicons were sequenced and an evolutionary tree was constructed using MEGA X software. A protein model was built employing the SWISS Model after protein translation using ExPASy online tool. The positivity rate of anti-HEV antibodies in serum samples was found as 56% (28/50). All Pakistani HEV showed homology with genotype 1 and shared common evolutionary origin and ancestry with HEV isolates of genotype 1 of London (MH504163), France (MN401238), and Japan (LC314158). Sequence analysis of motif regions assessment and protein structure revealed that the sequences had a similarity with the reference sequence. These data suggest that genotype 1 of HEV is circulating in Pakistan. This finding could be used for the diagnosis and control of HEV in the specific geographic region focusing on its prevalent genotype.

Clustered Cases of Waterborne Hepatitis E Virus Infection, France

The identification of seven cases of hepatitis E virus infection in a French rural hamlet in April 2015 led to investigations confirming the clustering and identifying the source of the infection. Laboratories and general practitioners in the area actively searched for other cases based on RT-PCR and serological tests. The environment, including water sources, was also checked for HEV RNA. Phylogenetic analyses were performed to compare HEV sequences. No other cases were found. Six of the seven patients lived in the same hamlet, and the seventh used to visit his family who lived there. All HEV strains were very similar and belonged to the HEV3f subgenotype, confirming the clustering of these cases. All the patients drank water from the public network. A break in the water supply to the hamlet was identified at the time the infection probably occurred; HEV RNA was also detected in a private water source that was connected to the public water network. The water flowing from the taps was quite turbid during the break. The private water supply containing HEV RNA was the likely source of the contamination. Private water supplies not disconnected from the public network are still frequent in rural areas, where they may contribute to public water pollution.

HEV Cell Culture

Cell culture is an important research method in virology. Although many attempts have been conducted to culture HEV in cells, only a few cell culture systems were considered to be efficient enough for usage. Concentration of virus stocks, host cells, and medium components affects the culture efficiency and the genetic mutations during HEV passage were found to be associated with the increased virulence in cell culture. As an alternative method for traditional cell culture, the infectious cDNA clones were constructed. The viral thermal stability, factors that impact the host range, post-translation of viral proteins, and function of different viral proteins were studied using the infectious cDNA clones. HEV cell culture studies on progeny virus showed that the viruses secreted from host cells have an envelope and its formation was associated with pORF3. This result explained the phenomenon that virus could infect host cells in the presence of anti-HEV antibodies.

Broadly Reactive Real-Time RT-PCR Assay for the Detection of Hepatitis E Virus and Simultaneous Genotyping by Single Nucleotide Polymorphism Analysis

Hepatitis E virus (HEV) infection is a global public health concern. Although HEV infection is usually asymptomatic and self-limiting, extrahepatic manifestations and chronic infections in immunocompromised patients have been described. HEV strains infecting humans have been classified into four main genotypes. In this study we have developed and validated a novel sensitive real-time RT-PCR assay for the detection of all four HEV genotypes. Simultaneous discrimination of genotypes 1, 2, and 4 from genotype 3 by single nucleotide polymorphism (SNP) analysis was possible. In all, 201 serum samples from cases and carriers previously tested for HEV by nested RT-PCR were analyzed. Twenty-seven HEV-positive samples could not be typed by the nested RT-PCR and nucleotide sequencing, but were newly typed by SNP analysis. As polymorphisms were present at the primer or probe binding site, we adopted a degenerate primer and mixed probes. When a mixed probe was added, the fluorescence intensity increased, facilitating genotype determination.

IMPORTANCE The distribution of HEV-3 and HEV-4 has been changing. HEV-4, which had been predominantly found in Asia, is now being detected in other parts of the world, and there are now reports of chronic infections. Additionally, neurological disorders have frequently been reported in patients with acute or chronic HEV infections. HEV-4 has also been shown to lead to a higher severity in terms of acute hepatitis than does HEV-3. Early typing can provide useful information regarding the route of infection and for tailoring treatment to the expected course of the disease. The present method afforded a good detection rate even when polymorphisms were present within the target region for viral gene detection. We believe that this method can be applied to the analysis of mutation-prone viral genes in the future.

Structural aspects of hepatitis E virus

Hepatitis E virus (HEV) is a leading cause of acute hepatitis worldwide. Hepatitis E is an enterically transmitted zoonotic disease that causes large waterborne epidemic outbreaks in developing countries and has become an increasing public-health concern in industrialized countries. In this setting, the infection is usually acute and self-limiting in immunocompetent individuals, although chronic cases in immunocompromised patients have been reported, frequently associated with several extrahepatic manifestations. Moreover, extrahepatic manifestations have also been reported in immunocompetent individuals with acute HEV infection. HEV belongs to the alphavirus-like supergroup III of single-stranded positive-sense RNA viruses, and its genome contains three partially overlapping open reading frames (ORFs). ORF1 encodes a nonstructural protein with eight domains, most of which have not been extensively characterized: methyltransferase, Y domain, papain-like cysteine protease, hypervariable region, proline-rich region, X domain, Hel domain, and RNA-dependent RNA polymerase. ORF2 and ORF3 encode the capsid protein and a multifunctional protein believed to be involved in virion release, respectively. The novel ORF4 is only expressed in HEV genotype 1 under endoplasmic reticulum stress conditions, and its exact function has not yet been elucidated. Despite important advances in recent years, the biological and molecular processes underlying HEV replication remain poorly understood, primarily due to a lack of detailed information about the functions of the viral proteins and the mechanisms involved in host-pathogen interactions. This review summarizes the current knowledge concerning HEV proteins and their biological properties, providing updated detailed data describing their function and focusing in detail on their structural characteristics. Furthermore, we review some unclear aspects of the four proteins encoded by the ORFs, highlighting the current key information gaps and discussing potential novel experimental strategies for shedding light on those issues.

Screening for hepatitis E virus genotype 3 in red deer (Cervus elaphus) and fallow deer (Dama dama), Portugal, 2018-2020

Hepatitis E virus (HEV) genotype 3 is the most prevalent HEV genotype in Europe causing mostly asymptomatic infections in humans, but can also sporadically cause severe acute hepatitis, chronic liver disease, chronic hepatitis in immunocompromised patients and extra-hepatic manifestations. Although much is today known about the swine reservoir, no information is available on the occurrence of HEV from widely distributed deer species in Portugal. Here, we investigated the presence and characterized HEV in free-living deer in Portugal by screening stools from red deer (Cervus elaphus) (n = 95) and fallow deer (Dama dama) (n = 35) for HEV by a broad-spectrum nested RT-PCR, followed by sequencing and phylogenetic analysis. Two red deer females, sampled in central Portugal, showed to be shedding HEV (2.1%; 95% confidence interval: 0.58-7.35). Sequencing and genetic characterization showed that these two deer HEV sequences were 98.96% identical to each other, being both of HEV genotype 3 subgenotype 3e. The increasing numbers and distribution of deer in Portugal and the zoonotic features of the circulating HEV genotype 3 subgenotype 3e highlights the importance of continued surveillance directed to food-borne diseases, especially those involving wild animals and deer in particular.

Screening of Swiss Pig Herds for Hepatitis E Virus: A Pilot Study

Hepatitis E virus (HEV) is an important cause of acute hepatitis in humans worldwide. In industrialised countries, most infections are caused by the zoonotic genotype 3. The main reservoir was found in pigs, with fattening pigs as the main shedders. The aim of this study was to establish a screening tool to detect HEV in pig farms. HEV-positive samples were sequenced using Sanger sequencing. First, different sample materials, including floor swabs, slurry, dust swabs and faeces were tested for HEV. Floor swabs turned out to give the best results and, in the form of sock swabs, were used for the screening of Swiss pig herds. A total of 138 pig farms were tested, with a focus on fattening pigs. Overall, 81 farms (58.8%) were HEV positive. Most sequences belonged to subtype 3h, in which they formed a specific cluster (Swiss cluster). In addition, subtype 3l and two unassigned sequences were detected. As a conclusion, sock swabs were found to be a helpful tool to screen pig herds for HEV and establish a sequence collection that may enable molecular epidemiology and support outbreak investigation and prevention.

Risk for Hepatitis E Virus Transmission by Solvent/Detergent-Treated Plasma

Hepatitis E has emerged as a major transfusion-transmitted infectious risk. Two recipients of plasma from 2 lots (A and B) of pooled solvent/detergent-treated plasma were found to be infected by hepatitis E virus (HEV) that was determined to have been transmitted by the solvent/detergent-treated plasma. HEV RNA viral loads were 433 IU in lot A and 55 IU in lot B. Retrospective studies found that 100% (13/13) of evaluable lot A recipients versus 18% (3/17) of evaluable lot B recipients had been infected by HEV (p<0.001), albeit not necessarily at time of transfusion. Among evaluable recipients, 86% with a transfused HEV RNA load >50,000 IU were infected, most likely by the HEV-containing solvent/detergent-treated plasma, versus only 7% with a transfused HEV RNA load <50,000 IU (p<0.001). Overall, solvent/detergent-treated plasma might harbor HEV. Such an occurrence might result in a dose-dependent risk for transfusion-transmitted hepatitis E.

Analyses of Clinical and Biological Data for French and Belgian Immunocompetent Patients Infected With Hepatitis E Virus Genotypes 4 and 3

Hepatitis E virus (HEV) genotypes 3 and 4 are the major causes of acute hepatitis in industrialized countries. Genotype 3 is mainly found in Europe and America, while genotype 4 is predominant in Asia. Several Japanese studies have suggested that genotype 4 is more virulent than genotype 3. We investigated this aspect by analyzing the clinical and biological data for 27 French and Belgian immunocompetent patients infected with HEV genotype 4. Their infections were probably acquired locally, since none of these patients reported traveling outside France or Belgium during the 2–8 weeks before symptoms onset. Each patient was matched for age (±5 years) and gender with two patients infected with HEV genotype 3. Bivariate analysis indicated that the HEV genotype 4-infected patients had significantly higher alanine aminotransferase (ALT) (2067 IU/L) and aspartate aminotransferase (AST) (1581 IU/L) activities and total bilirubin concentrations (92.4 μmol/L) than did those infected with HEV genotype 3 (1566 IU/L, p = 0.016; 657 IU/L, p = 0.003 and 47 μmol/L, p = 0.046) at diagnosis. In contrast, more patients infected with HEV genotype 3 reported dark urine (71% vs. 39%, p = 0.02) and experienced asthenia (89% vs. 58%, p < 0.01) than did those infected with HEV genotype 4. Two HEV genotype 4-infected patients died of multi-organ failure, while none of the genotype 3-infected patients died (p = 0.035). Finally, stepwise regression analysis retained only a greater increase in ALT (odds-ratio: 1.0005, 95% confidence interval: 1.00012–1.00084) and less frequent fever (odds-ratio = 0.1244; 95% confidence interval: 0.01887–0.82020) for patients infected with HEV genotype 4. We conclude that HEV-4 infections are likely to be associated with higher ALT activity than HEV-3 infections. Additional immunological and virological studies are required to confirm these findings and better understand the influence, if any, of genotype on HEV pathophysiology.

Classification of the Zoonotic Hepatitis E Virus Genotype 3 Into Distinct Subgenotypes

Hepatitis E virus (HEV) genotype 3 is the most common genotype linked to HEV infections in Europe and America. Three major clades (HEV-3.1, HEV-3.2, and HEV-3.3) have been identified but the overlaps between intra-subtype and inter-subtype p-distances make subtype classification inconsistent. Reference sequences have been proposed to facilitate communication between researchers and new putative subtypes have been identified recently. We have used the full or near full-length HEV-3 genome sequences available in the Genbank database (April 2020; n = 503) and distance analyses of clades HEV-3.1 and HEV-3.2 to determine a p-distance cut-off (0.093 nt substitutions/site) in order to define subtypes. This could help to harmonize HEV-3 genotyping, facilitate molecular epidemiology studies and investigations of the biological and clinical differences between HEV-3 subtypes.

No evidence of sexual transmission of HEV among individuals using HIV pre-exposure prophylaxis

We investigated the seroprevalence and incidence of hepatitis E virus (HEV) infection in men who have sex with men (MSM) who have been exposed to pre-exposure prophylaxis (PrEP) against HIV as sexual transmission of HEV has been suggested. A total of 147 PrEP-using MSM and 147 blood donors matched for sex, age and geographical area were tested for anti-HEV IgG and IgM. Among them, 135 have been followed for 1 year, at the end of which serological tests for HEV were performed retrospectively on stored samples. Laboratory data on sexual transmitted infections (STIs) and viral hepatitis, including hepatitis A virus (HAV), were collected. Baseline seroprevalence rates in PrEP users were 42.2% (anti-HEV IgG) and 3.4% (anti-HEV IgM). Those of the control blood donors were similar (anti-HEV IgG 43.5% and anti-HEV IgM 4.1%). There was no incident of HEV infection despite the rates of bacterial STIs (incidence rate (IR) = 46.6%) and HAV infection (IR = 15.8%). Age was the only risk factor associated with anti-HEV IgG seropositivity at baseline and at the end of follow-up. Sexual transmission does not seem to be a major route of HEV infection in MSM, unlike HAV.

Full-length genome sequencing of RNA viruses-How the approach can enlighten us on hepatitis C and hepatitis E viruses

Among the five main viruses responsible for human hepatitis, hepatitis C virus (HCV) and hepatitis E virus (HEV) are different while sharing similarities. Both viruses can be transmitted by blood or derivatives whereas HEV can also follow environmental or zoonotic routes. These highly variable RNA viruses can cause chronic hepatitis potentially leading to hepatocarcinoma. HCV and HEV can develop new structures and functions under selective pressure to adapt to host immunity, human tissues, treatments or even various animal reservoirs. Elsewhere, with directly acting antiviral treatments, HCV can be eradicated whereas HEV is an emerging pathogen against which specific treatments have to be improved. As a unique molecular tool able to explore viral genomic plasticity, full-length genome (FLG) sequencing has become easier, faster and cheaper. The present review will show how FLG sequencing can explore these RNA viruses with the aim to investigate key genomics data to improve basic knowledge, patients' healthcare and preventive tools.

Clinical Characteristics of Acute Hepatitis E and Their Correlation with HEV Genotype 3 Subtypes in Italy

Genotype 3 (GT3) is responsible for most European autochthonous hepatitis E virus (HEV) infections. This study analyzed circulating genotypes and GT3 subtypes in the Lazio region, Italy, between 2011 and 2019, as well as their pathogenic characteristics. Of the 64 evaluable HEV GT3 patient-derived sequences, identified subtypes included GT3f (n = 36), GT3e (n = 15), GT3c (n = 9), GT3a (n = 1) and three unsubtyped GT3 sequences. GT3c strains were similar to Dutch sequences (96.8–98.1% identity), GT3e strains showed high similarity (96.8%) with a United Kingdom sequence, while the most related sequences to GT3f Italian strains were isolated in France, Belgium and Japan. One sequence was closely related to another Italian strain isolated in raw sewage in 2016. The liver functioning test median values for 56 evaluable GT3 patients were: alanine aminotransferase (ALT), 461 (range 52–4835 U/L); aspartate aminotransferase (AST), 659 (range 64–6588 U/L); and total bilirubin, 3.49 (range 0.4–33 mg/dL). The median HEV RNA viral load for 26 evaluable GT3 patients was 42,240 IU/mL (range 5680–895,490 IU/mL). Of the 37 GT3 patients with available clinical information, no correlation was observed between HEV clinical manifestations and GT3 subtype. HEV symptoms were comparable among GT3c/e/f patients across most analyzed categories except for epigastric pain, which occurred more frequently in patients with HEV GT3e (75%) than in patients with GT3c (50%) or GT3f (19%) (p = 0.01). Additionally, patients with HEV GT3c exhibited significantly higher median international normalized ratio (INR) than patients with GT3e and GT3f (p = 0.033). The severity of GT3 acute hepatitis E was not linked to HEV RNA viral load or to the GT3 subtype.

Pegylated interferon may be considered in chronic viral hepatitis E resistant to ribavirin in kidney transplant recipients

Background

Hepatitis E virus (HEV) may be resistant to immunosuppression reduction and ribavirin treatment in kidney transplant recipients because of mutant strains and severe side effects of ribavirin which conduct to dose reduction. Sofosbuvir efficacy is controversial. Peg-interferon 2 alpha (PEG-IFN) is currently contraindicated due to a high risk of acute humoral and cellular rejection. The present study assessed, for the first time, the effect of PEG-IFN in a kidney transplant recipient infected with HEV.

Case presentation

The patient had chronic active HEV that was resistant to immunosuppression reduction and optimal ribavirin treatment. He developed significant liver fibrosis. PEG-IFN was administered for 10 months, and it was well tolerated and did not induce rejection. A sustained virological response was obtained.

Conclusions

We conclude that prolonged treatment with PEG-IFN in kidney transplant recipients infected with HEV could be considered as a salvage option.

Hepatitis E infection is an infrequent cause of acute hepatitis in the metropolitan area of Buenos Aires

Background Argentina is considered a region of low seroprevalence of hepatitis E virus (HEV), however; no studies have evaluated its burden among acute hepatitis cases.

OBJECTIVES

We aimed to estimate the proportion of acute HEV and outcome in a cohort of patients with acute hepatitis from 6 liver units in the Metropolitan area of Buenos Aires (MABA).

STUDY DESIGN

We performed a prospective cohort study including patients ≥18 years with acute hepatitis (increase in transaminases x 5 ULN) fromJuly 2016 to May 2018. Severe hepatitis was defined as acute hepatitis + INR> 1.5 and acute liver failure as severe hepatitis + encephalopathy. In patients in whom other etiologies were excluded, HEV tests were performed: anti-HEV IgM/G and HEV-RNA in serum and feces.

RESULTS

Overall, 268 patients with acute hepatitis were included in the study. The most frequent etiologies of acute hepatitis were hepatitis B (67patients, 25 %), hepatotoxicity (65, 24 %) and autoimmune hepatitis (26, 10 %). Acute HEV infection was confirmed in 8 (2.98 %; 95 %CI 1.25-5.63) patients who tested positive for anti-HEV IgM. A total of 63 (23.5 %) patients were hospitalized and 9 (3.3 %) patients died. Overall, 48 (18 %) patients developed severe hepatitis, 6 (2.2 %) have acute liver failure, 6 (1.9 %) underwent liver transplantation and 9 (3.4 %) patients died.

CONCLUSIONS

the proportion of acute HEV in MABA was low during the period studied. We believe our findings will aid physicians prioritize other etiologies of acute hepatitis over HEV in order to optimize diagnostic resources and offer better care to their patients.

Does HEV-3 subtype play a role in the severity of acute hepatitis E?

Hepatitis E virus genotype 3 (HEV-3) is a major aetiologic agent of acute hepatitis in industrialized countries. Two main HEV-3 subtypes are found in Europe: subtypes 3c and 3f. We have analysed the clinical and biological parameters from 100 French immunocompetent patients with an HEV subtype 3f or subtype 3c infection, included in a prospective multicentre study. Stepwise regression analysis found that infections with HEV subtype 3f were associated with fever (OR: 6.1 95%CI: 1.4-26.1), have a greater virus load (OR: 7.4; 95%CI: 1.3-42.2) and require more frequent hospitalization (OR: 7.6; 95%CI: 1.1-51.4) than those infected with subtype 3c. The directed acyclic graph strengthens the multivariate analyses indicating a direct link between the HEV subtype, HEV RNA concentration, fever and hospitalization. Further studies on patients in other European countries are needed to confirm this relationship and determine the underlying mechanism.

Hepatitis E in pigs in Israel: seroprevalence, molecular characterisation and potential impact on humans

IntroductionThe zoonotic hepatitis E virus (HEV) genotype 3 (HEV-G3) has become a common cause of acute and chronic hepatitis among humans worldwide. In Israel, while HEV-3 sequences have previously been detected in sewage, only the non-zoonotic HEV-G1 genotype has been found in samples from human patients.AimIn this pilot study, we aimed to assess the status of HEV in a sample of the swine population and among swine farm workers in Israel.MethodsPig blood (n = 141) and faecal samples (n = 39), pig farm sewage samples (n = 8) and blood from farm workers (n = 24) were collected between February 2016 and October 2017. Anti-HEV IgG was detected using the Wantai assay. HEV RNA was analysed with the RealStar HEV kit. HEV open reading frame 1 fragments amplified from representative HEV RNA-positive samples were used for phylogenetic analysis.ResultsOverall prevalence of HEV antibodies in pigs was 75.9% (107/141). HEV RNA was detected in plasma (2.1%, 3/141), faecal (22.8%, 18/79) and pig sewage (4/8) samples. Pig and sewage-derived viral sequences clustered with previously identified human sewage HEV-G3 sequences. Most pig farms workers (23 of 24) were HEV-seropositive; none was viraemic or reported previous clinical signs.ConclusionsThis study showed that domestic pigs in Israel are infected with HEV-G3. The high HEV seropositivity of the farm workers together with the previous identification of this virus in human sewage suggests circulation to humans. The clinical impact of these findings on public health should be further explored.

Plasma Hepatitis E Virus Kinetics in Solid Organ Transplant Patients Receiving Ribavirin

Hepatitis E virus (HEV) infection causes chronic hepatitis in solid organ transplant (SOT) recipients. Antiviral therapy consists of three months of ribavirin, although response rates are not optimal. We characterized plasma HEV kinetic patterns in 41 SOT patients during ribavirin therapy. After a median pharmacological delay of three (range: 0-21) days, plasma HEV declined from a median baseline level of 6.12 (3.53-7.45) log copies/mL in four viral kinetic patterns: (i) monophasic (n = 18), (ii) biphasic (n = 13), (iii) triphasic (n = 8), and (iv) flat-partial response (n = 2). The mean plasma HEV half-life was estimated to be 2.0 ± 0.96 days. Twenty-five patients (61%) had a sustained virological response (SVR) 24 weeks after completion of therapy. Viral kinetic patterns (i)-(iii) were not associated with baseline characteristics or outcome of therapy. A flat-partial response was associated with treatment failure. All patients with a log concentration decrease of plasma HEV at day seven of >15% from baseline achieved SVR. In conclusion, viral kinetic modeling of plasma HEV under ribavirin therapy showed, for the first time, four distinct kinetic profiles, a median pharmacologic delay of three days, and an estimated HEV half-life of two days. Viral kinetic patterns were not associated with response to therapy, with the exception of a flat-partial response.

Hepatitis E Virus Infections among Patients with Acute Febrile Jaundice in Burkina Faso

Hepatitis E virus infection is a significant public health problem in many parts of the world including Africa. We tested serum samples from 900 patients in Burkina Faso presenting with febrile icterus. They all tested negative for yellow fever, but those from 23/900 (2.6%) patients contained markers of acute HEV infection (anti-HEV IgM and HEV RNA positive). Genotyping indicated that 14 of the strains were HEV genotype 2b. There was an overall HEV IgG seroprevalence of 18.2% (164/900). In a bivariate analysis, the factors linked to HEV exposure were climate and patient age. Older patients and those living in arid regions were more likely to have HEV infection. HEV genotype 2b circulating only in humans can be involved in some acute febrile icterus cases in Burkina Faso. Better access to safe water, sanitation, and improved personal hygiene should improve control of HEV infection in this country.

Monitoring human enteric viruses in wastewater and relevance to infections encountered in the clinical setting: a one-year experiment in central France, 2014 to 2015

Human enteric viruses are resistant in the environment and transmitted via the faecal-oral route. Viral shedding in wastewater gives the opportunity to track emerging pathogens and study the epidemiology of enteric infectious diseases in the community. Aim: The aim of this study was to monitor the circulation of enteric viruses in the population of the Clermont-Ferrand area (France) by analysis of urban wastewaters. Methods: Raw and treated wastewaters were collected between October 2014 and October 2015 and concentrated by a two-step protocol using tangential flow ultrafiltration and polyethylene glycol precipitation. Processed samples were analysed for molecular detection of adenovirus, norovirus, rotavirus, parechovirus, enterovirus (EV), hepatitis A (HAV) and E (HEV) viruses. Results: All wastewater samples (n = 54) contained viruses. On average, six and four virus species were detected in, respectively, raw and treated wastewater samples. EV-positive samples were tested for EV-D68 to assess its circulation in the community. EV-D68 was detected in seven of 27 raw samples. We collected data from clinical cases of EV-D68 (n = 17), HAV (n = 4) and HEV infection (n = 16) and compared wastewater-derived sequences with clinical sequences. We showed the silent circulation of EV-D68 in September 2015, the wide circulation of HAV despite few notifications of acute disease and the presence in wastewater of the major HEV subtypes involved in clinical local cases. Conclusion: The environmental surveillance overcomes the sampling bias intrinsic to the study of infections associated with hospitalisation and allows the detection in real time of viral sequences genetically close to those reported in clinical specimens.

Hepatitis E virus genotype 3 and capsid protein in the blood and urine of immunocompromised patients

OBJECTIVES

Hepatitis E virus genotype 3 (HEV3) is responsible for acute and chronic liver disease in solid organ transplant (SOT) recipients. HEV was recently found in the urine of some acutely and chronically genotype 4-infected patients.

METHODS

We examined the urinary excretion of HEV3 by 24 consecutive SOT recipients at the acute phase of HEV hepatitis and characterized the excreted virus.

RESULTS

Urinary HEV RNA was detected in 12 (50%) of the 24 transplanted patients diagnosed with HEV hepatitis. Urinary HEV antigen (Ag) was detected in all but one of the patients (96%). The density of RNA-containing HEV particles in urine was low (1.11-1.12 g/cm³), corresponding to lipid-associated virions. The urinary HEV RNA/Ag detected was not associated with impaired kidney function or de novo proteinuria. Finally, there was more HEV Ag in the serum at the acute phase of HEV infection in SOT recipients whose infection became chronic.

CONCLUSIONS

HEV3 excreted via the urine of SOT recipients at the acute phase of HEV hepatitis has a lipid envelope. Renal function was not impaired. While urinary HEV Ag was a sensitive indicator of HEV infection, only acute phase serum HEV Ag indicated the development of a chronic infection.

Molecular and in vitro characterisation of hepatitis E virus from UK pigs

Hepatitis E virus (HEV) infection is widespread in the global pig population. Although clinically inapparent in pigs, HEV infection is the cause of Hepatitis E in humans and transmission via the food chain has been established. Following a 2013 study that investigated prevalence of HEV infection in UK slaughter-age pigs samples indicating highest viral load were selected for further characterisation. High throughput sequencing was used to obtain the complete coding sequence from five samples. An in-frame insertion was observed within the HEV hypervariable region in two samples. To interrogate whether this mutation may be the cause of high-level viraemia and faecal shedding as observed in the sampled pigs virus isolation and culture was conducted. Based on viral growth kinetics there was no evidence that these insertions affected replication efficiency in vitro, suggesting as yet undetermined host factors may affect the course of infection and consequently the risk of foodborne transmission.

Transmission and Epidemiology of Hepatitis E Virus Genotype 3 and 4 Infections

Following the introduction of robust serological and molecular tools, our understanding of the epidemiology of zoonotic hepatitis E virus (HEV) has improved considerably in recent years. Current thinking suggests that consumption of pork meat products is the key route of infection in humans, but it is certainly not the only one. Other routes of infection include environmental spread, contaminated water, and via the human blood supply. The epidemiology of HEV genotype (gt)3 and gt4 is complex, as there are several sources and routes of infection, and it is likely that these vary between and within countries and over time.

Short communication: detection and molecular characterization of hepatitis E virus in domestic animals of São Tomé and Príncipe

As in most of the African continent, the status of hepatitis E virus (HEV) infection in domestic animals in São Tomé and Príncipe, an archipelago off the western equatorial coast of Central Africa, is also completely unknown. In the present study, we investigated the presence of HEV among domestic animals in São Tomé and Príncipe. A total of 93 stool samples from different animal species (goat, cow, pig, chicken, duck, and monkey) were tested for HEV RNA using two real-time RT-PCR assays, followed by a nested RT-PCR assay for sequencing and phylogenetic analysis. A total of six samples (1 cow stool and 5 pig stools) were found to be positive for HEV RNA of which one pig stool was positive by broad spectrum nested RT-PCR. Phylogenetic analysis showed that the retrieved sequence clustered within HEV subgenotype 3f, similar to zoonotic strains of European countries and posing interesting questions on past introduction of European HEV into São Tomé and Príncipe archipelago. This is the first report describing the presence and molecular characterization of HEV in São Tomé and Príncipe.

Hiding in Plain Sight? It's Time to Investigate Other Possible Transmission Routes for Hepatitis E Virus (HEV) in Developed Countries

Historically in developed countries, reported hepatitis E cases were typically travellers returning from countries where hepatitis E virus (HEV) is endemic, but now there are increasing numbers of non-travel-related ("autochthonous") cases being reported. Data for HEV in New Zealand remain limited and the transmission routes unproven. We critically reviewed the scientific evidence supporting HEV transmission routes in other developed countries to inform how people in New Zealand may be exposed to this virus. A substantial body of indirect evidence shows domesticated pigs are a source of zoonotic human HEV infection, but there is an information bias towards this established reservoir. The increasing range of animals in which HEV has been detected makes it important to consider other possible animal reservoirs of HEV genotypes that can or could infect humans. Foodborne transmission of HEV from swine and deer products has been proven, and a large body of indirect evidence (e.g. food surveys, epidemiological studies and phylogenetic analyses) support pig products as vehicles of HEV infection. Scarce data from other foods suggest we are neglecting other potential sources of foodborne HEV infection. Moreover, other transmission routes are scarcely investigated in developed countries; the role of infected food handlers, person-to-person transmission via the faecal-oral route, and waterborne transmission from recreational contact or drinking untreated or inadequately treated water. People have become symptomatic after receiving transfusions of HEV-contaminated blood, but it is unclear how important this is in the overall hepatitis E disease burden. There is need for broader research efforts to support establishing risk-based controls.

Acute hepatitis E in French patients and neurological manifestations

OBJECTIVES

Hepatitis E virus (HEV) is a major cause of acute hepatitis worldwide. However, our understanding of the source of contamination is incomplete and the frequency of neurological manifestations in still unknown.

METHODS

200 eligible cases reported to the French National Reference Center from January 2015 to December 2015 were prospectively included in this case-control study (1 case: 1 control, matched for sex, age and area of living) to investigate the risk of infection. We documented the factors associated with their HEV infection and clinical manifestations.

RESULTS

The 200 HEV-infected patients included 137 who were immunocompetent and 63 immunocompromised. The factors associated with an HEV infection were contact with farm animals, eating pork liver sausage and eating unpeeled fruit. The 33 patients (16.5%) who reported neurological symptoms included 14 with neuropathic pain suggesting small fiber neuropathy, 9 with painless sensory disorders, 6 with Parsonage-Turner syndrome, one Guillain-Barre syndrome, one meningitis, one encephalitis and one diplopia. Neurological manifestations were more frequent in immunocompetent patients (22.6% vs 3.2%, p < 0.001).

CONCLUSIONS

This study highlights the risk of HEV transmission by the environment in industrialized countries. The higher frequency of neurological disorders in immunocompetent patients suggests pathophysiological mechanisms involving the immune system.

An Update on the Clinicopathologic Features and Pathologic Diagnosis of Hepatitis E in Liver Specimens

Infection with the hepatitis E virus (HEV) is globally seen a leading cause of hepatitis. Now increasingly recognized also in industrialized countries, hepatitis E constitutes a significant health problem worldwide. The patient's immune status determines the clinical course and histopathology of hepatitis E. In immunocompetent patients, hepatitis E usually follows an asymptomatic or subclinical course, but may also present with acute hepatitis. In contrast, immunocompromised patients may develop chronic hepatitis, and patients with preexisting liver diseases are at risk for liver decompensation with potentially fatal outcome. Whereas pathologists only occasionally encounter liver biopsies from immunocompetent individuals with hepatitis E, they are more likely exposed to biopsies from patients with preexisting liver disease or immunocompromised individuals. Histopathologic hallmarks of hepatitis E in immunocompetent patients comprise lobular disarray, lobular, and portal inflammation, as well as hepatocyte necrosis of varying extend and regeneration. Thus, it is similar to acute non-E viral hepatitis, yet further differential diagnoses include autoimmune hepatitis and drug-induced liver injury. Histopathologic findings of hepatitis E in preexisting liver disease are determined by the underlying pathology, but may be more severe. Histopathologic presentation of hepatitis E in immunocompromised patients is highly variable, ranging from minimal active hepatitis to chronic hepatitis with severe activity and progressive fibrosis. Taken together, the variability of the histologic features depending on the clinical context and the overlap with other liver diseases make the histopathologic diagnosis of hepatitis E challenging. Immunohistochemistry for HEV open reading frame 2 protein and molecular testing for HEV RNA are useful tissue-based ancillary tools.

Diversity of hepatitis E virus genotype 3

Hepatitis E virus genotype 3 (HEV-3) can lead to chronic infection in immunocompromised patients, and ribavirin is the treatment of choice. Recently, mutations in the polymerase gene have been associated with ribavirin failure but their frequency before treatment according to HEV-3 subtypes has not been studied on a large data set. We used single-molecule real-time sequencing technology to sequence 115 new complete genomes of HEV-3 infecting French patients. We analyzed phylogenetic relationships, the length of the polyproline region, and mutations in the HEV polymerase gene. Eighty-five (74%) were in the clade HEV-3efg, 28 (24%) in HEV-3chi clade, and 2 (2%) in HEV-3ra clade. Using automated partitioning of maximum likelihood phylogenetic trees, complete genomes were classified into subtypes. Polyproline region length differs within HEV-3 clades (from 189 to 315 nt). Investigating mutations in the polymerase gene, distinct polymorphisms between HEV-3 subtypes were found (G1634R in 95% of HEV-3e, G1634K in 56% of HEV-3ra, and V1479I in all HEV-3efg, clade HEV-3ra, and HEV-3k strains). Subtype-specific polymorphisms in the HEV-3 polymerase have been identified. Our study provides new complete genome sequences of HEV-3 that could be useful for comparing strains circulating in humans and the animal reservoir.

Development of new hepatitis E vaccines

Hepatitis E virus (HEV) infection is an emerging zoonotic disease posing a severe threat to public health in the world, especially to pregnant women. Currently, no specific treatments are available for HEV infection. Therefore, it is crucial to develop vaccine to prevent this infection. Although several potential candidate vaccines against HEV have been studied for their immunogenicity and efficacy, only Hecolin® which is developed by Xiamen Innovax Biotech Co., Ltd. and approved by China Food and Drug Administration (CFDA) in 2012, is the licensed HEV vaccine in the world so far. Extensive studies on safety, immunogenicity and efficacy in phase III clinical trials have shown that Hecolin® is a promising vaccine for HEV prevention and control. In this article, the advances on HEV vaccine development and research are briefly reviewed.

Hepatitis E Virus: A New Foodborne Zoonotic Concern

Hepatitis E virus (HEV) is an enteric nonenveloped single-stranded RNA virus. Among the mammalian lineages, four genotypes are associated to human infection: genogroups 1 and 2 infect only humans and are mainly found in developing countries, while genogroups 3 and 4 are zoonotic, being found in a variety of animal species including pigs, and are autochthonous in developed countries. HEV infection can result in liver damage and with genotypes 1 and 2 symptoms can be particularly severe in pregnant women, with a high lethality ratio. Several cases of foodborne transmission of hepatitis E have been reported, often involving consumption of meat, especially raw or undercooked. Information is lacking on the exact extent of foodborne transmission of HEV.

Metagenomics for the study of viruses in urban sewage as a tool for public health surveillance

The application of next-generation sequencing (NGS) techniques for the identification of viruses present in urban sewage has not been fully explored. This is partially due to a lack of reliable and sensitive protocols for studying viral diversity and to the highly complex analysis required for NGS data processing. One important step towards this goal is finding methods that can efficiently concentrate viruses from sewage samples. Here the application of a virus concentration method based on skimmed milk organic flocculation (SMF) using 10L of sewage collected in different seasons enabled the detection of many viruses. However, some viruses, such as human adenoviruses, could not always be detected using metagenomics, even when quantitative PCR (qPCR) assessments were positive. A targeted metagenomic assay for adenoviruses was conducted and 59.41% of the obtained reads were assigned to murine adenoviruses. However, up to 20 different human adenoviruses (HAdV) were detected by this targeted assay being the most abundant HAdV-41 (29.24%) and HAdV-51 (1.63%). To improve metagenomics' sensitivity, two different protocols for virus concentration were comparatively analysed: an ultracentrifugation protocol and a lower-volume SMF protocol. The sewage virome contained 41 viral families, including pathogenic viral species from families Caliciviridae, Adenoviridae, Astroviridae, Picornaviridae, Polyomaviridae, Papillomaviridae and Hepeviridae. The contribution of urine to sewage metavirome seems to be restricted to a few specific DNA viral families, including the polyomavirus and papillomavirus species. In experimental infections with sewage in a rhesus macaque model, infective human hepatitis E and JC polyomavirus were identified. Urban raw sewage consists of the excreta of thousands of inhabitants; therefore, it is a representative sample for epidemiological surveillance purposes. The knowledge of the metavirome is of significance to public health, highlighting the presence of viral strains that are circulating within a population while acting as a complex matrix for viral discovery.

Detection of Genotype 1a and 1f of Hepatitis E Virus in Patients Treated at Tertiary Care Hospitals in Central India

BACKGROUND AND AIMS

An acute hepatitis, caused by hepatitis E virus (HEV), is a significant global health concern, especially in developing countries. HEV has 1 serotype and 8 genotypes, which are further divided into subtypes. Despite the availability of sporadic cases and outbreak data from India, specific information regarding HEV epidemiological data is lacking from central India. This study was conducted to understand epidemiological and molecular features of HEV in central India.

METHODS

In this 3-year study conducted from July 2012 to June 2015, IgM ELISA was used for the diagnosis of suspected HEV cases. For identifying the genotype, nRT PCR was conducted and the PCR products were sequenced and analysed. Clinical and demographic data were analysed using statistical tools to highlight the trends.

RESULT

Out of 1,369 suspected cases, 341 (24.9%) were positive for HEV. The positivity was significantly higher in males (69.2%) and in the age group of > 15-45 years (72.5%). The HEV cases peaked during the summer. Subtypes 1a and 1f of genotype 1 were detected in the area during the study period.

CONCLUSION

HEV is a major aetiological agent of viral hepatitis in central India with adults and males at higher risk of infection. Two subtypes of the virus were detected in the region. Continuous serological surveillance and molecular monitoring will help to understand the epidemiology of HEV infection, outbreak mitigation and aid in providing treatment.

Transfusion-acquired hepatitis E infection misdiagnosed as severe critical illness polyneuromyopathy in a heart transplant patient

This is the case of a 56-year-old man who underwent heart transplantation. Within the first postoperative days, his respiratory and limb muscles weakened, which was attributed to critical illness polyneuromyopathy (CIPM). At day 70 post transplantation, he had increased liver enzyme levels and acute hepatitis E virus (HEV) infection was diagnosed. HEV RNA was found in the serum, stools, and cerebrospinal fluid. Results of further investigations suggested a possible HEV-related polyradiculoneuropathy. At transplantation, the patient was negative for immunoglobulin (Ig)G, IgM, and HEV RNA. A trace-back procedure identified the source of infection and concluded that HEV infection was contracted from blood transfusion 12 days prior to transplantation from an HEV RNA-positive donor. Tests of the organ donor for HEV were negative. Phylogenetic analysis revealed sequence homology between the HEV-3 strain of the patient and the HEV-3 strain of the blood donor. Despite ribavirin treatment, the patient died on day 153 post transplantation from multiorgan failure. In conclusion, patients with hepatitis or neuropathic illness who have received blood products should be screened for HEV.

Identification of sapovirus GV.2, astrovirus VA3 and novel anelloviruses in serum from patients with acute hepatitis of unknown aetiology

Hepatitis is a general term meaning inflammation of the liver, which can be caused by a variety of viruses. However, a substantial number of cases remain with unknown aetiology. We analysed the serum of patients with clinical signs of hepatitis using a metagenomics approach to characterize their viral species composition. Four pools of patients with hepatitis without identified aetiological agents were evaluated. Additionally, one pool of patients with hepatitis E (HEV) and pools of healthy volunteers were included as controls. A high diversity of anelloviruses, including novel sequences, was found in pools from patients with hepatitis of unknown aetiology. Moreover, viruses recently associated with gastroenteritis as sapovirus GV.2 and astrovirus VA3 were also detected only in those pools. Besides, most of the HEV genome was recovered from the HEV pool. Finally, GB virus C and human endogenous retrovirus were found in the HEV and healthy pools. Our study provides an overview of the virome in serum from hepatitis patients suggesting a potential role of these viruses not previously described in cases of hepatitis. However, further epidemiologic studies are necessary to confirm their contribution to the development of hepatitis.

Rabbit Hepatitis E Virus Infections in Humans, France

Hepatitis E virus (HEV) has been detected in rabbits, but whether rabbit HEV strains can be transmitted to humans is not known. Of 919 HEV-infected patients in France during 2015-2016, five were infected with a rabbit HEV strain. None of the patients had direct contact with rabbits, suggesting foodborne or waterborne infections.

Hepatitis E Virus and the Liver: Clinical Settings and Liver Pathology

Infection with hepatitis E virus (HEV) is a leading cause of acute hepatitis worldwide, now increasingly recognized also in nonendemic regions. Clinical manifestation of hepatitis E includes mostly asymptomatic/subclinical presentations or acute, self-limiting hepatitis, but also potentially fatal liver failure or chronic hepatitis in immunocompromised individuals. Accordingly, hepatitis E histolpathologic patterns range from an unremarkable histology over acute (cholestatic) hepatitis with variable degree of necrosis to chronic hepatitis with fibrosis. Awareness of hepatitis E and its differential diagnoses, knowledge of its clinico-pathologic manifestations and familiarity with its diagnostic tools will enable clinicians and pathologists to competently make this diagnosis.

Inactivation of Viruses and Bacteriophages as Models for Swine Hepatitis E Virus in Food Matrices

Hepatitis E virus has been recognised as a food-borne virus hazard in pork products, due to its zoonotic properties. This risk can be reduced by adequate treatment of the food to inactivate food-borne viruses. We used a spectrum of viruses and bacteriophages to evaluate the effect of three food treatments: high pressure processing (HPP), lactic acid (LA) and intense light pulse (ILP) treatments. On swine liver at 400 MPa for 10 min, HPP gave log₁₀ reductions of ≥4.2, ≥5.0 and 3.4 for feline calicivirus (FCV) 2280, FCV wildtype (wt) and murine norovirus 1 (MNV 1), respectively. Escherichia coli coliphage ϕX174 displayed a lower reduction of 1.1, while Escherichia coli coliphage MS2 was unaffected. For ham at 600 MPa, the corresponding reductions were 4.1, 4.4, 2.9, 1.7 and 1.3 log₁₀. LA treatment at 2.2 M gave log₁₀ reductions in the viral spectrum of 0.29-2.1 for swine liver and 0.87-3.1 for ham, with ϕX174 and MNV 1, respectively, as the most stable microorganisms. The ILP treatment gave log₁₀ reductions of 1.6-2.8 for swine liver, 0.97-2.2 for ham and 1.3-2.3 for sausage, at 15-60 J cm^-2, with MS2 as the most stable microorganism. The HPP treatment gave significantly (p < 0.05) greater virus reduction on swine liver than ham for the viruses at equivalent pressure/time combinations. For ILP treatment, reductions on swine liver were significantly (p < 0.05) greater than on ham for all microorganisms. The results presented here could be used in assessments of different strategies to protect consumers against virus contamination and in advice to food producers. Conservative model indicators for the pathogenic viruses could be suggested.

HEV infection in French HIV-infected patients

OBJECTIVES

The reported prevalence of anti-hepatitis E virus antibodies in HIV-positive patients from industrialized countries varies greatly. It is also difficult to compare these data with the anti-IgG prevalence in the general population because age and sex are not matched in most studies. Moreover, MSM are at increased risk of viral hepatitis.

METHODS

HEV is endemic in southwestern France. We investigated therefore 300 HIV-infected patients consecutively attending the out-patient clinic of Toulouse University Hospital. Each HIV-infected patient was matched for sex and age with 2 healthy blood donors from the same area. They were tested for anti-HEV IgM and IgG.

RESULTS

Anti-HEV IgG was found in 116 HIV-infected patients (38.7%) and in 284 matched controls (47.3%, p = 0.027). However, anti-HEV IgG concentration tended to be lower in HIV-patients than in controls. Anti-HEV IgM prevalence was similar HIV-infected patients (3.6%) and in matched controls (3.8%, p = 0.85).

CONCLUSION

The prevalence and concentrations of anti-HEV IgG in HIV-infected patients from Southern-France were lower than in controls, suggesting a weaker humoral response. But their prevalences of anti-HEV IgM were similar, indicating a high incidence of HEV infection. These data do not indicate that HEV is transmitted sexually.

Characterization of the Specificity, Functionality, and Durability of Host T-Cell Responses Against the Full-Length Hepatitis E Virus

The interplay between host antiviral immunity and immunopathology during hepatitis E virus (HEV) infection determines important clinical outcomes. We characterized the specificity, functionality, and durability of host T-cell responses against the full-length HEV virus and assessed a novel "Quantiferon" assay for the rapid diagnosis of HEV infection. Eighty-nine volunteers were recruited from Oxford, Truro (UK), and Toulouse (France), including 44 immune-competent patients with acute HEV infection, 18 HEV-exposed immunosuppressed organ-transplant recipients (8 with chronic HEV), and 27 healthy volunteers. A genotype 3a peptide library (616 overlapping peptides spanning open reading frames [ORFs] 1-3) was used in interferon-gamma (IFN-γ) T-cell ELISpot assays. CD4⁺ /CD8⁺ T-cell subsets and polyfunctionality were defined using ICCS and SPICE analysis. Quantification of IFN-γ used whole-blood stimulation with recombinant HEV-capsid protein in the QuantiFERON kit. HEV-specific T-cell responses were detected in 41/44 immune-competent HEV exposed volunteers (median magnitude: 397 spot-forming units/10⁶ peripheral blood mononuclear cells), most frequently targeting ORF2. High-magnitude, polyfunctional CD4 and CD8⁺ T cells were detected during acute disease and maintained to 12 years, but these declined over time, with CD8⁺ responses becoming more monofunctional. Low-level responses were detectable in immunosuppressed patients. Twenty-three novel HEV CD4⁺ and CD8⁺ T-cell targets were mapped predominantly to conserved genomic regions. QuantiFERON testing demonstrated an inverse correlation between IFN-γ production and the time from clinical presentation, providing 100% specificity, and 71% sensitivity (area under the receiver operator characteristic curve of 0.86) for HEV exposure at 0.3 IU/mL.

CONCLUSION

Robust HEV-specific T-cell responses generated during acute disease predominantly target ORF2, but decline in magnitude and polyfunctionality over time. Defining HEV T-cell targets will be important for the investigation of HEV-associated autoimmune disease. (Hepatology 2016;64:1934-1950).

Detection of Hepatitis E Virus in Sewage After an Outbreak on a French Island

A hepatitis E outbreak, which occurred on a small isolated island, provided an opportunity to evaluate the association between the number of hepatitis E cases in the community and the concentration of virus detected in sewage. Samples were collected from the different sewage treatment plants from the island and analyzed for the presence of hepatitis E (HEV) virus using real-time RT-PCR. We demonstrated that if 1-4 % of inhabitants connected to a WWTP were infected with HEV, raw sewage contained HEV at detectable levels. The finding that such a small number of infected people can contaminate municipal sewage works raises the potential of the further distribution of the virus. Indeed, investigating the routes of transmission of HEV, including the potential for sewage effluent to contain infectious HEV, may help us to better understand the epidemiology of this pathogen, which is considered to be an emerging concern in Europe.

Quantification of HEV RNA by Droplet Digital PCR

The sensitivity of real-time PCR for hepatitis E virus (HEV) RNA quantification differs greatly among techniques. Standardized tools that measure the real quantity of virus are needed. We assessed the performance of a reverse transcription droplet digital PCR (RT-ddPCR) assay that gives absolute quantities of HEV RNA. Analytical and clinical validation was done on HEV genotypes 1, 3 and 4, and was based on open reading frame (ORF)3 amplification. The within-run and between-run reproducibilities were very good, the analytical sensitivity was 80 HEV RNA international units (IU)/mL and linearities of HEV genotype 1, 3 and 4 were very similar. Clinical validation based on 45 samples of genotype 1, 3 or 4 gave results that correlated well with a validated reverse transcription quantitative PCR (RT-qPCR) assay (Spearman rs = 0.89, p < 0.0001). The RT-ddPCR assay is a sensitive method and could be a promising tool for standardizing HEV RNA quantification in various sample types.