Review article: hepatitis E-a concise review of virology, epidemiology, clinical presentation and therapy

A World Health Organization Human Hepatitis E Virus Reference Strain Related to Similar Strains Isolated from Rabbits

We report here the genome sequence of a hepatitis E virus (HEV) strain from a chronically infected immunodeficient patient. Full-length sequence analysis revealed a distinct HEV strain, of a tentative new subgenotype, clustering with viruses from rabbits. It is a World Health Organization reference strain for validation of nucleic acid testing.

Hepatitis E virus - key points for the clinical haematologist

In recent years there has been a paradigm shift in our understanding of the epidemiology and clinical features of hepatitis E virus (HEV) infection. Once classically described as an acute hepatitis associated with waterborne outbreaks in areas of poor sanitation, HEV is now recognised to be endemic in Europe and is probably zoonotic in origin. Evidence for transfusion-transmitted HEV has prompted the introduction of blood donor screening in a number of countries, but the risk to the haematology patient from food sources remains. The aim of this review therefore, is to equip the clinical haematologist with the knowledge required to diagnose HEV infection and to aid decision-making in patient management. The article also provides information on addressing patient concerns about their risk of acquiring hepatitis E and how this risk can be mitigated.

Hepatitis E virus infection of slaughtered healthy pigs in Brazil

Hepatitis E virus (HEV) is an emerging pathogen that can be transmitted through contaminated raw or undercooked meat derived from domestic pigs. HEV infections have been documented among pig herds, pig products and environmental samples raising concern about the spread of the virus. HEV genotypes 3 and 4 are considered zoonotic and have been linked to human cases. HEV was detected in 51 of 335 bile samples (15.2%) from healthy pigs in Minas Gerais, Brazil. Phylogenetic analysis of partial sequences from ORF1 and ORF2 regions yielded discordant results, assigning isolates to subtypes 3c and 3i, respectively, suggesting intragenotypic HEV recombination.

Proposal for a new subtype of the zoonotic genotype 3 Hepatitis E virus: HEV-3l

The near-complete genomic sequences of two hepatitis E virus (HEV) strains, detected from feces of infected pigs, were obtained. Phylogenetic analysis and p-distance comparisons of the complete coding regions showed a close relationship to the French swine strain FR-SHEV3c-like detected in 2006 (p-distance value 0.101), belonging to HEV-3 but not assigned to any known subtype. The three HEV sequences showed, relatively high nucleotide distances (p-distance >0.129) compared to the other defined HEV subtype references and unclassified strains. The HEV classification criteria and the high sequence similarity suggest that these strains can be assigned to a putative novel subtype of genotype 3, HEV-3l.

Hepatitis E virus infection

Hepatitis E virus (HEV) infection can lead to acute and chronic hepatitis as well as to extrahepatic manifestations such as neurological and renal disease; it is the most common cause of acute viral hepatitis worldwide. Four genotypes are responsible for most infection in humans, of which HEV genotypes 1 and 2 are obligate human pathogens and HEV genotypes 3 and 4 are mostly zoonotic. Until quite recently, HEV was considered to be mainly responsible for epidemics of acute hepatitis in developing regions owing to contamination of drinking water supplies with human faeces. However, HEV is increasingly being recognized as endemic in some developed regions. In this setting, infections occur through zoonotic transmission or contaminated blood products and can cause chronic hepatitis in immunocompromised individuals. HEV infections can be diagnosed by measuring anti-HEV antibodies, HEV RNA or viral capsid antigen in blood or stool. Although an effective HEV vaccine exists, it is only licensed for use in China. Acute hepatitis E is usually self-limiting and does not require specific treatment. Management of immunocompromised individuals involves lowering the dose of immunosuppressive drugs and/or treatment with the antiviral agent ribavirin.

Systematic review with meta-analysis: the association between hepatitis E seroprevalence and haemodialysis

BACKGROUND

Hepatitis E virus (HEV) infection appears to be more common than previously thought. HEV seroprevalence in patients on maintenance haemodialysis (HD) is unclear with a range from 0% to 44%. In addition, risk factors of transmission of HEV in patients on haemodialysis are unknown.

AIM

To perform a systematic review and meta-analysis of HEV seroprevalence in HD patients compared with controls.

METHODS

A systematic search of several databases identified all observational studies with comparative arms. Two reviewers extracted data and assessed the methodological quality. A random-effects model was used for pooled odds ratio (OR) and 95% confidence interval (CI) of positive anti-HEV IgG in both groups. Heterogeneity and publication bias were assessed with appropriate tests.

RESULTS

We identified 31 studies from 17 countries between 1994 and 2016. Sixteen studies were judged to have adequate quality and 15 to have moderate limitations. HEV infection was more prevalent in patients on haemodialysis compared with controls (OR 2.47, 95% CI 1.79-3.40, I² = 75.2%, P < .01). We conducted several subgroup analyses without difference in results. Egger regression test did not suggest publication bias (P = .83). Specific risk factors of HEV transmission in patients on haemodialysis were not clearly identified.

CONCLUSIONS

Hepatitis E virus infection is more prevalent in patients on haemodialysis compared with non-haemodialysis control groups. Further studies are needed to determine risk factors of acquisition, impact on health, and risk for chronic HEV especially among those patients going to receive organ transplantation.

Seroepidemiology of hepatitis E virus infection in pigs in Durango State, Mexico

No information about hepatitis E virus (HEV) infection in pigs in the northern Mexican state of Durango exists. We determined the seroprevalence and correlates of anti-HEV IgG antibodies in pigs in Durango, Mexico. Through a cross-sectional study, we studied 427 pigs raised in backyards (n = 328), or slaughtered (n = 99) in Durango. Sera of pigs were analyzed for anti-HEV IgG antibodies using a commercially available enzyme-linked immunoassay. Antibodies to HEV were found in 193 (45.2%) of the 427 pigs studied. A significantly higher seroprevalence was observed in slaughtered pigs (79.8%) than in backyard pigs (34.8%). Bivariate analysis showed that HEV seropositivity was associated with age, sex, breed, climate, altitude, mean annual temperature, mean annual rainfall, and farm raising. Logistic regression analysis showed that HEV seropositivity was associated with the origin (Sonora State) of pigs (OR=6.51; 95%CI: 3.74-11.32; P < 0.001), and mean annual rainfall (≤600 mm) (OR=1.78; 95%CI: 1.01-3.15; P = 0.04). A high seroprevalence of HEV infection in pigs slaughtered for human consumption in Durango City was found. This is the first report of an association between HEV seropositivity in pigs and climatic factors. Infection factors found may help for the optimal planning of preventive measures against HEV infection.