Epidemiology of mammalian hepatitis E virus infection

Label-free ultra-sensitive colorimetric detection of hepatitis E virus based on oxidase-like activity of MnO2 nanosheets

Hepatitis E virus (HEV) is an evolving infectious entity that causes viral hepatitis infections worldwide. Current routine methods of identifying and diagnosing HEV are someway laborious and costly. Based on the biomimicking oxidase-like activity of MnO₂ nanosheets, we designed a label-free, highly sensitive colorimetric sensing technique for HEV detection. The prepared MnO₂ catalyst displays intrinsic biomimicking oxidase-like catalytic activity and efficiently oxidizes the 3,3',5,5'-tetramethylbenzidine (TMB) substrate from colorless to blue colored oxidized TMB (oxTMB) product which can be measured at 652 nm by UV-visible spectrum. When the HEV-DNA was added, DNA adsorbed easily on MnO₂ surface through physical adsorption and electrostatic interaction which hinders the oxidase-like catalytic activity of MnO₂. Upon the introduction of target, the HEV target DNA binds with its complementary ssDNA on the surface of MnO₂, the hybridized DNA releases from the surface of MnO₂, which leads to recovery of oxidase-like catalytic activity of MnO₂. This strategy was applied to construct a colorimetric technique for HEV detection. The approach works in the linear range of 1 fM-100 nM DNA concentration with the limit of detection (LOD) of 3.26 fM (S/N = 3) and quantitative limit (LOQ) of 36.08 fM. The TMB-MnO₂ platform was highly selective for HEV target DNA detection when compared with potential interferences. Result of serum sample analysis demonstrates that this sensing system can be used for clinical diagnostic applications.

Fulminant Transfusion-Associated Hepatitis E Virus Infection Despite Screening, England, 2016-2020

In England, all blood donations are screened in pools of 24 by nucleic acid test (NAT) for hepatitis E virus (HEV) RNA. During 2016-2020, this screening successfully identified and intercepted 1,727 RNA-positive donations. However, review of previous donations from infected platelet donors identified 9 donations in which HEV RNA detection was missed, of which 2 resulted in confirmed transmission: 1 infection resolved with ribavirin treatment, and 1 proceeded to fatal multiorgan failure within a month from infection. Residual risk calculations predict that over the 5-year study period, HEV RNA detection was missed by minipool NAT in 12-23 platelet and 177-354 whole-blood donations, but transmission risk remains undetermined. Although screening has been able to largely eliminate infectious HEV from the blood supply in England, missed detection of low levels of HEV RNA in donated blood can lead to a severe, even fulminant, infection in recipients and could be prevented by more sensitive screening.

Assessment of hepatitis E seropositivity among HIV-infected patients in Bulgaria

It is debatable whether HIV-infected patients are at greater risk for hepatitis E virus (HEV) infection compared with healthy subjects. The reported anti-HEV seroprevalence among different groups in Bulgaria varied from 9.04% to 25.9%, but the information regarding the HIV population is still missing. The aim of the present study was to evaluate hepatitis E seroprevalence among HIV-infected patients in Bulgaria and to analyze demographic and immunological factors associated with HEV infection. Serum samples of 312 HIV-infected patients were analyzed retrospectively. Age, sex, residence and laboratory markers for HEV, HBV, HCV and HIV infection, and lymphocytes subpopulations were collected for all patients. None of the tested samples were positive for HEV RNA. HEV seroprevalence among HIV-infected patients was 10.9%. Males were more affected with the highest prevalence of positivity in the age group > 30 to ≤ 40 years. The documented HIV transmission routes in HIV/HEV co-infected group were heterosexual, homosexual, intravenous drug use (IDU), and vertical with predominace of the heterosexual route (z = 0.2; p = 0.804). There was a statistically significant trend of HIV mixed infection with routes of HIV transmission other than homosexual - heterosexual in HIV/HEV group and injection drug use in HIV/HBV/HCV co-infected group. The route of HIV transmission, in contexts of patients’ behavior, was associated with HEV prevalence among HIV-infected patients.

Seroprevalence of hepatitis E virus in Lithuanian domestic pigs and wildlife

Hepatitis E is an important public health concern disease that causes acute hepatitis in humans with different hepatitis E virus strains reported among domestic and wild animals. In Lithuania, seroprevalence studies on animals considered to be possible virus reservoirs, particularly in wildlife species, had never been investigated before. In order to assess the actual distribution of the virus in the domestic pig and wildlife species, serum samples originating from different geographic areas of Lithuania were tested for the presence of antibodies to the virus using enzyme-linked immunosorbent assay. The study results proved that hepatitis E virus infection is prevalent among domestic pigs, wild boar, moose, and roe deer in Lithuania, with the overall prevalence of IgG antibodies against hepatitis E virus being 43.75%, 57.05%, 11.76%, and 1.20%, respectively. Significantly higher (P< 0.01) seroprevalence values of 53.66% and 80% were observed in weaned pigs and adult wild boar. Herds with 15 001–30 000 pigs were 2.4 times more likely (P< 0.01) to test positive for hepatitis E virus antibodies (70.18%), than herds with ≤ 500 pigs (21.11%). The differences in seroprevalence rates between domestic pigs (from 25 to 66.67%) and wild boar (from 42.86 to 73.33% ) in all 10 counties were not significant (P> 0.05). Estimated low seroprevalence rate in moose, roe deer and absence of antibodies in red deer suggest that such wildlife species are accidental hosts of hepatitis E virus or at least hepatitis E virus is not present in Lithuanian cervides.

Autochthonous infection with hepatitis E virus related to subtype 3a, France: a case report

Hepatitis E virus (HEV) recently emerged in Europe as a cause of autochthonous acute hepatitis and a porcine zoonosis. European autochthonous cases almost exclusively involved viruses of genotype 3, subtype 3a being only recently reported in France, from farm pigs. We report an autochthonous human infection with a HEV related to subtype 3a in Southeastern France. A 55-year-old human immunodeficiency virus-infected man presented liver cytolysis in June 2014. HEV RNA was detected in serum and three months later, anti-HEV IgM and IgG were positive whereas HEV RNA was no more detectable in serum. No biological or clinical complication did occur. HEV phylogeny based on two capsid gene fragments showed clustering of sequences obtained from the case-patient with HEV-3a, mean nucleotide identity being 91.7 and 91.3% with their 10 best GenBank matches that were obtained in Japan, South Korea, USA, Canada, Germany and Hungria from humans, pigs and a mongoose. Identity between HEV sequence obtained here and HEV-3a sequences obtained at our laboratory from farm pigs sampled in 2012 in Southeastern France was only 90.2-91.4%. Apart from these pig sequences, best hits from France were of subtypes 3i, 3f, or undefined. The patient consumed barely cooked wild-boar meat; no other risk factor for HEV infection was documented. In Europe, HEV-3a has been described in humans in England and Portugal, in wild boars in Germany, and in pigs in Germany, the Netherlands, and, recently, France. These findings suggest to gain a better knowledge of HEV-3a circulation in France.

Markers for Ongoing or Previous Hepatitis E Virus Infection Are as Common in Wild Ungulates as in Humans in Sweden

Hepatitis E virus (HEV) is a human pathogen with zoonotic spread, infecting both domestic and wild animals. About 17% of the Swedish population is immune to HEV, but few cases are reported annually, indicating that most infections are subclinical. However, clinical hepatitis E may also be overlooked. For identified cases, the source of infection is mostly unknown. In order to identify whether HEV may be spread from wild game, the prevalence of markers for past and/or ongoing infection was investigated in sera and stool samples collected from 260 hunted Swedish wild ungulates. HEV markers were found in 43 (17%) of the animals. The most commonly infected animal was moose (Alces alces) with 19 out of 69 animals (28%) showing HEV markers, followed by wild boar (Sus scrofa) with 21 out of 139 animals (15%), roe deer (Capreolus capreolus) with 2 out of 30 animals, red deer (Cervus elaphus) with 1 out of 15 animals, and fallow deer (Dama dama) 0 out of 7 animals. Partial open reading frame 1 (ORF1) of the viral genomes from the animals were sequenced and compared with those from 14 endemic human cases. Phylogenetic analysis revealed that three humans were infected with HEV strains similar to those from wild boar. These results indicate that wild animals may be a source of transmission to humans and could be an unrecognized public health concern.

Diagnostic Performance of Five Assays for Anti-Hepatitis E Virus IgG and IgM in a Large Cohort Study

Determination of anti-hepatitis E virus (anti-HEV) antibodies is still enigmatic. There is no gold standard, and results obtained with different assays often diverge. Herein, five assays were compared for detection of anti-HEV IgM and IgG. Serum samples from 500 Swedish blood donors and 316 patients, of whom 136 had suspected HEV infection, were analyzed. Concordant results for IgM and IgG with all assays were obtained only for 71% and 70% of patients with suspected hepatitis E, respectively. The range of sensitivity for anti-HEV detection was broad (42% to 96%); this was reflected in the detection limit, which varied up to 19-fold for IgM and 17-fold for IgG between assays. HEV RNA was analyzed in all patients and in those blood donors reactive for anti-HEV in any assay, and it was found in 26 individuals. Among all of the assays, both anti-HEV IgG and IgM were detected in 10 of those individuals. Twelve had only IgG and, in 7 of those 12, IgG was only detected with the two most sensitive assays. Three of the HEV-RNA-positive samples were negative for anti-HEV IgM and IgG in all assays. With the two most sensitive assays, anti-HEV IgG was identified in 16% of the blood donor samples and in 66% of patients with suspected HEV infection. Because several HEV-RNA-positive samples had only anti-HEV IgG without anti-HEV IgM or lacked anti-HEV antibodies, analysis for HEV RNA may be warranted as a complement in the laboratory diagnosis of ongoing HEV infection.

An Epidemiologic Investigation of a Case of Acute Hepatitis E

Hepatitis E virus (HEV) is considered a zoonotic infection in developed nations. A case of acute hepatitis E in a researcher following a scalpel injury while working on a pig prompted a seroepidemiologic study to identify potential modes of transmission and determine the seroprevalence of HEV among animal handlers at the institute. Sera from personnel (n = 64) in two animal facilities and age/sex-matched blood donors (n = 63) as controls were tested for IgG anti-HEV and, if positive, for IgM anti-HEV and HEV RNA. Sera and stool from pigs aged 6 to 12 weeks from the breeding farm and older pigs from animal facilities were tested similarly. The median age of personnel was 36 years, 74% were white, 56% were male, and 74% had direct exposure to pigs. The prevalence of anti-HEV was 3.1% among personnel compared to 3.2% among blood donors; none were positive for IgM anti-HEV or HEV RNA. IgG anti-HEV was detected in sera from 10% of pigs aged 6 to 8 weeks, 80% aged 10 weeks, 100% aged 12 weeks, and 76% aged >12 weeks. HEV RNA was detected in stool but not sera from three 12-week-old pigs. Sequencing revealed HEV genotype 3 with ∼10% difference between the patient and pig sequences. Parenteral transmission is a potential mode of acute HEV infection. The low and similar seroprevalence of anti-HEV between the at-risk group and age-matched blood donors suggests low transmission risk with universal precautions among animal handlers.

Hepatitis E virus in patients with decompensated chronic liver disease: a prospective UK/French study

BACKGROUND

In developed countries, hepatitis E is a porcine zoonosis caused by hepatitis E virus (HEV) genotype 3. In developing countries, hepatitis E is mainly caused by genotype 1, and causes increased mortality in patients with pre-existing chronic liver disease (CLD).

AIM

To determine the role of HEV in patients with decompensated CLD.

METHODS

Prospective HEV testing of 343 patients with decompensated CLD at three UK centres and Toulouse France, with follow-up for 6 months or death. IgG seroprevalence was compared with 911 controls.

RESULTS

11/343 patients (3.2%) had acute hepatitis E infection, and three died. There were no differences in mortality (27% vs. 26%, OR 1.1, 95% CI 0.28-4.1), age (P = 0.9), bilirubin (P = 0.5), alanine aminotransferase (P = 0.06) albumin (P = 0.5) or international normalised ratio (P = 0.6) in patients with and without hepatitis E infection. Five cases were polymerase chain reaction (PCR) positive (genotype 3). Hepatitis E was more common in Toulouse (7.9%) compared to the UK cohort (1.2%, P = 0.003). HEV IgG seroprevalence was higher in Toulouse (OR 17, 95% CI 9.2-30) and Truro (OR 2.5, 95% CI 1.4-4.6) than in Glasgow, but lower in cases, compared to controls (OR 0.59, 95% CI 0.41-0.86).

CONCLUSIONS

Hepatitis E occurs in a minority of patients with decompensated chronic liver disease. The mortality is no different to the mortality in patients without hepatitis E infection. The diagnosis can only be established by a combination of serology and PCR, the yield and utility of which vary by geographical location.

Hepatitis E Virus of Subtype 3a in a Pig Farm, South-Eastern France

Hepatitis E virus (HEV) has emerged during the past decade as a causative agent of autochthonous hepatitis and is a clinical concern in Western developed countries. It has been increasingly recognized that pigs are a major reservoir of HEV of genotypes 3 and 4 worldwide and pig-derived food items represent a potential source of infections by these viruses in humans. Hepatitis E virus RNA testing was performed here on faeces from rectal swabs sampled in 2012 from 50 3-month-old farm pigs from the same farm located in south-eastern France than in a previous work conducted in 2007. Pig HEV sequences corresponding to genomic fragments of ORF2 and ORF1 genes were obtained after RT-PCR amplification with in-house protocols. Hepatitis E virus genotype was determined by phylogenetic analysis. Prevalence was similar to that determined 5 years earlier (68% versus 62%). Two robust phylogenetic clusters of HEV subtypes 3a and 3f were identified, and these sequences obtained in 2012 largely differ compared with those obtained in 2007. Notably, HEV sequences obtained in 2012 from a majority (62%) of the infected pigs belonged to subtype 3a, which was not previously described in France, including not being found in any of humans, pigs or wild boars. Further studies are needed to assess the circulation of HEV-3a in pigs and humans in this country. In addition, along with previous findings, this study supports the need for increased information to the public on the risk of HEV infection through contacts with pigs or consumption of pig-derived products in France.

Molecular detection of hepatitis E virus in sheep from southern Xinjiang, China

Hepatitis E virus (HEV) is a causative agent of infectious hepatitis in animals and humans both in developing and developed countries. Here, we collected 500 sheep sera and 75 raw sheep liver samples from a slaughterhouse in the southern part of the Xinjiang region, China, along with 26 sera of butchers from the same slaughterhouse. All serum samples were tested for anti-HEV antibody by enzyme-linked immunosorbent assay. Both serum and liver samples were evaluated for the presence of HEV RNA by nested polymerase chain reaction targeting partial nucleotide sequences of open reading frame 2 (ORF2). The results indicate that sheep seroprevalence was 35.20 % (176/500) and that four of the 75 (5.3 %) sheep livers showed detectable amounts of HEV RNA. The seroprevalence of the butchers was 57.7 % (15/26). The four amplicons shared 97.8-100 % nucleotide sequence identity and had pairwise sequence identities of 81.6-85.3 %, 84.2-85.3 %, 82.1-85.3 % and 84.7-97.9 % with the corresponding regions of genotypes 1, 2, 3 and 4 of HEV, respectively. A phylogenetic tree was constructed based on alignments of an amplified 186-bp ORF2 sequence and corresponding reference strains. The analysis showed that the four sheep strains detected in our study formed a lineage within a genotype 4 cluster that contains hb-3, bjsw1, T1, swCH189 and swCH25, all of which belong to genotype 4, subtype 4d. The results indicated a high level of seroconversion in sheep and suggested that sheep liver may be a source of foodborne HEV infection in humans.

Systematic serological testing for hepatitis E virus in kidney transplant recipients

Hepatitis E virus (HEV) genotype 3 is endemic in Europe and hyperendemic in southern France. Recent reports of a high prevalence of HEV RNA in blood donations and in culinary specialties from this geographical area confirmed the endemicity of HEV and sources of viral transmission in this geographical area. HEV causes acute and chronic hepatitis in solid organ transplant recipients. Since March 2012, we have implemented systematic HEV serological testing in our cohort of kidney transplant recipients (KTRs) in Marseille in southeastern France. The aim of our study was to assess HEV exposure in this cohort between March 2012 and May 2014. During these 27 months, we found that 39% of the patients who underwent kidney transplantation had an anti-HEV IgG response using a sensitive microplate enzyme immunoassay. This seroprevalence was approximately 43% at both 1 and 8 years after, using the same assay. In addition, systematic HEV serological testing detected 6 cases of HEV infection among 578 KTRs (1%) during the 27 months of the study, with 5 at an acute stage and 1 at a chronic stage. In conclusion, continuous HEV monitoring in this population is useful for better understanding the epidemiology of HEV in France, because these patients are a well-monitored population. Moreover, HEV monitoring in KTRs is clinically relevant because HEV represents a clinical threat in these patients. Nevertheless, HEV serological testing may be more fruitful for identifying HEV infections when performed in cases of biological liver abnormalities than when performed systematically.

Optimization of the elution buffer and concentration method for detecting hepatitis E virus in swine liver using a nested reverse transcription-polymerase chain reaction and real-time reverse transcription-polymerase chain reaction

The aim of this study was to develop an optimal technique for detecting hepatitis E virus (HEV) in swine livers. Here, three elution buffers and two concentration methods were compared with respect to enhancing recovery of HEV from swine liver samples. Real-time reverse transcription-polymerase chain reaction (RT-PCR) and nested RT-PCR were performed to detect HEV RNA. When phosphate-buffered saline (PBS, pH 7.4) was used to concentrate HEV in swine liver samples using ultrafiltration, real-time RT-PCR detected HEV in 6 of the 26 samples. When threonine buffer was used to concentrate HEV using polyethylene glycol (PEG) precipitation and ultrafiltration, real-time RT-PCR detected HEV in 1 and 3 of the 26 samples, respectively. When glycine buffer was used to concentrate HEV using ultrafiltration and PEG precipitation, real-time RT-PCR detected HEV in 1 and 3 samples of the 26 samples, respectively. When nested RT-PCR was used to detect HEV, all samples tested negative regardless of the type of elution buffer or concentration method used. Therefore, the combination of real-time RT-PCR and ultrafiltration with PBS buffer was the most sensitive and reliable method for detecting HEV in swine livers.

Genome sequence of a hepatitis e virus of genotype 3e from a chronically infected kidney transplant recipient

Hepatitis E virus (HEV) is an emerging cause of acute and chronic hepatitis in immunocompromised patients in Europe. We report the genome sequence of a genotype 3e HEV from a chronically infected kidney transplant recipient in southeastern France, the second HEV genome sequence from a transplant recipient and the first of subtype 3e.

Fatal fulminant hepatitis E associated with autoimmune hepatitis and excessive paracetamol intake in Southeastern France

We present, to our knowledge, the first case of fatal fulminant liver failure associated with hepatitis E virus infection, autoimmune hepatitis, and excessive paracetamol intake, which occurred in a 77-year-old woman. Hepatitis E testing should be performed in severe acute liver failure cases, even when another cause has been identified.

Hepatitis E virus genotype 1 infection of swine kidney cells in vitro is inhibited at multiple levels

Genotype 1 hepatitis E viruses (HEVs) are restricted to primate hosts, whereas genotype 3 HEVs predominantly infect swine, in addition to primates. In order to identify possible determinants of the host range, infectious recombinant viruses and chimeras of a genotype 1 isolate and a genotype 3 isolate were compared for their ability to infect versus transfect cultured human HepG2/C3A cells and swine LLC-PK cells. The patterns of luciferase expression from virus replicons containing the Gaussia luciferase gene in place of the viral ORF2 or ORF3 genes demonstrated that translation of the ORF2 capsid gene of genotype 1 virus is severely inhibited in swine kidney cells compared to its translation in rhesus macaque kidney or human liver cells. Therefore, this virus may produce insufficient capsid protein for optimal assembly in swine cells. Infectivity assays with a virus containing a chimeric capsid protein confirmed that amino acids 456 to 605 of the virus capsid protein comprised the virus receptor-binding region and suggested that genotype 1 viruses may be prevented from infecting swine because genotype 1 viruses are unable to enter swine cells. Rhesus macaque cells appeared to be better than human cells for growing the genotype 1 virus. These cell and virus combinations may serve as a useful in vitro model with which to study determinants of the natural host range of this virus.

Emergence of autochthonous infections with hepatitis E virus of genotype 4 in Europe

In Europe, autochthonous hepatitis E is caused by genotype 3 hepatitis E virus (HEV) in almost all cases. A total of 15 infections with genotype 4 HEV were diagnosed in France from May 2009 to April 2012, and all but one of the HEV-4 strains implicated in these infections were genetically related and highly similar to HEV-4 sequences isolated from swine in Belgium. In addition, 5 autochthonous HEV-4 infections have been described in the region of Lazio, Italy, during March and April 2011, and these HEV sequences were 100% identical to one another but showed relatively low similarity (74-85%) to HEV-4 RNA samples collected in France. We report 6 additional HEV-4 infections that were diagnosed from May to July 2012 which represented 50% of the HEV infections diagnosed during this period in our clinical microbiology laboratory. Five of these HEV-4 strains were associated with autochthonous infections and were clustered together and with the majority of HEV-4 previously described in France, whereas the sixth strain was genetically divergent. Taken together with reports from other teams, these observations indicate that autochthonous infections with HEV-4 are emerging in Europe and have been transmitted by at least two distinct sources.