Hepatitis E: Genotypes, strategies to prevent and manage, and the existing knowledge gaps

Hepatitis E and Potential Public Health Implications from a One-Health Perspective: Special Focus on the European Wild Boar (Sus scrofa)

The hepatitis E virus (HEV) has become increasingly important in recent years in terms of risk for public health, as the main causative agent of acute viral hepatitis. It is a foodborne disease transmitted to humans through the consumption of contaminated water or contaminated food. Human-to-human transmission is sporadic and is linked to transfusions or transplants. The main reservoirs of the hepatitis E virus are domestic pigs and wild boars, although, compared to pigs, wild boars represent a lesser source of risk since their population is smaller and the consumption of derived products is more limited. These peculiarities often make the role of the wild boar reservoir in the spread of the disease underestimated. As a public health problem that involves several animal species and humans, the management of the disease requires an interdisciplinary approach, and the concept of "One Health" must be addressed. In this direction, the present review intends to analyze viral hepatitis E, with a particular focus on wild boar. For this purpose, literature data have been collected from different scientific search engines: PubMed, MEDLINE, and Google scholar, and several keywords such as "HEV epidemiology", "Extrahepatic manifestations of Hepatitis E", and "HEV infection control measures", among others, have been used. In the first part, the manuscript provides general information on the disease, such as epidemiology, transmission methods, clinical manifestations and implications on public health. In the second part, it addresses in more detail the role of wild boar as a reservoir and the implications related to the virus epidemiology. The document will be useful to all those who intend to analyze this infectious disease from a "One-Health" perspective.

From discovery to treatment: tracing the path of hepatitis E virus

The hepatitis E virus (HEV) is a major cause of acute viral hepatitis worldwide. HEV is classified into eight genotypes, labeled HEV-1 through HEV-8. Genotypes 1 and 2 exclusively infect humans, while genotypes 3, 4, and 7 can infect both humans and animals. In contrast, genotypes 5, 6, and 8 are restricted to infecting animals. While most individuals with a strong immune system experience a self-limiting infection, those who are immunosuppressed may develop chronic hepatitis. Pregnant women are particularly vulnerable to severe illness and mortality due to HEV infection. In addition to liver-related complications, HEV can also cause extrahepatic manifestations, including neurological disorders. The immune response is vital in determining the outcome of HEV infection. Deficiencies in T cells, NK cells, and antibody responses are linked to poor prognosis. Interestingly, HEV itself contains microRNAs that regulate its replication and modify the host's antiviral response. Diagnosis of HEV infection involves the detection of HEV RNA and anti-HEV IgM/IgG antibodies. Supportive care is the mainstay of treatment for acute infection, while chronic HEV infection may be cleared with the use of ribavirin and pegylated interferon. Prevention remains the best approach against HEV, focusing on sanitation infrastructure improvements and vaccination, with one vaccine already licensed in China. This comprehensive review provides insights into the spread, genotypes, prevalence, and clinical effects of HEV. Furthermore, it emphasizes the need for further research and attention to HEV, particularly in cases of acute hepatitis, especially among solid-organ transplant recipients.

Hepatitis E Virus Genotype 3 among Hemodialysis Patients in Mexico: First Identification of Chronic Infection

The global distribution of hepatitis E virus (HEV) is attributed to its capacity to spread through several routes of transmission; hemodialysis has gained increased amounts of attention in recent years. Although Mexico is considered a hyperendemic region for hepatitis E, no HEV surveillance is performed in the country. The frequency of HEV in hemodialysis (HD) patients has not been determined. Herein, we conducted a cross-sectional single-center analytical study including 67 serum samples from HD patients. Anti-HEV IgG and IgM antibodies and the viral genome were determined; partial regions within the HEV genome were sequenced for further phylogenetic analysis. Globally, 14.9% of the tested patients exhibited reactivity for IgG antibodies against HEV, and none showed reactivity to IgM. A total of 5.9% of the samples showed HEV genome amplification, and sequencing confirmed the identity of genotype 3; subsequent analysis of positive cases revealed two acute cases and chronic hepatitis E infection in one patient. Notably, the chronic patient was negative for anti-HEV IgG antibodies. Our findings highlight the importance of viral genome testing in HD patients and the need to establish guidelines for HEV detection in Mexico.

Seroprevalence of Hepatitis-E Virus-Immunoglobulin G and its association with Chronic Liver Disease

Background & Objective

Viral hepatitis is a major public health concern in low-middle income countries. Hepatitis-E infection (HEV) is found globally but most prevalent in low-income countries especially those with poor sanitation systems, access to clean drinking water and health services. Superinfection with HEV in patients with chronic liver disease (CLD) can cause severe hepatic decompensation leading to increased morbidity and mortality. To determine the frequency of seroprevalence of Hepatitis-E virus Immunoglobulin g (IgG) and its association with chronic liver disease.

Methods

A cross-sectional study was conducted in Asian Institute of Medical Sciences, Hyderabad, Pakistan from January till May 2022. A total of 196 patients of aged ≥ 18 years, presenting in gastroenterology clinics were included in the study after informed consent.

Result

Among 196 patients, one third of patient were male (73.5%). Out of which 162 (82.7%) had liver disease and 34 (17.3%) were without liver disease. The median age of patient was 45 (33-51) years. The overall seroprevalence of HEV IgG among study population was 69.4%. HEV IgG was present in 114 and 22 in CLD and non CLD patients respectively. Multivariable regression shows no association between seroprevalence of HEV in CLD and non-CLD patient (AOR 1.02, 95% CI 0.45-2.313).

Conclusion

Our study showed high frequency of HEV seropositivity. No difference was observed in HEV seropositivity among CLD and non-CLD patients.

Label-Free Quantitative Analysis of Pig Liver Proteome after Hepatitis E Virus Infection

Hepatitis E represents an emerging zoonotic disease caused by the Hepatitis E virus (HEV), for which the main route of transmission is foodborne. In particular, infection in humans has been associated with the consumption of contaminated undercooked meat of pig origin. The aim of this study was to apply comparative proteomics to determine if porcine liver protein profiles could be used to distinguish between pigs seropositive and seronegative for HEV. Preliminarily, an ELISA was used to evaluate the presence of anti-HEV antibodies in the blood serum of 136 animals sent to slaughter. Among the analyzed samples, a seroprevalence of 72.8% was estimated, and it was also possible to identify 10 animals, 5 positive and 5 negative, coming from the same farm. This condition created the basis for the quantitative proteomics comparison between homogeneous animals, in which only the contact with HEV should represent the discriminating factor. The analysis of the proteome in all samples of liver exudate led to the identification of 554 proteins differentially expressed between the two experimental groups, with 293 proteins having greater abundance in positive samples and 261 more represented in negative exudates. The pathway enrichment analysis allowed us to highlight the effect of the interaction between HEV and the host biological system in inducing the potential enrichment of 69 pathways. Among these, carbon metabolism stands out with the involvement of 41 proteins, which were subjected to interactomic analysis. This approach allowed us to focus our attention on three enzymes involved in glycolysis: glucose-6-phosphate isomerase (GPI), glyceraldehyde-3-phosphate dehydrogenase (GAPDH), and fructose-bisphosphate aldolase A (ALDOA). It therefore appears that infection with HEV induced a strengthening of the process, which involves the breakdown of glucose to obtain energy and carbon residues useful for the virus's survival. In conclusion, the label-free LC-MS/MS approach showed effectiveness in highlighting the main differences induced on the porcine liver proteome by the interaction with HEV, providing crucial information in identifying a viral signature on the host metabolism.

Viral Biology and Immune Privilege in the Development of Extrahepatic Manifestations During Hepatitis E Virus Infection

Hepatitis E virus (HEV) exhibits tropism toward hepatocytes and thus affects the liver; however, HEV may also affect other tissues, including the heart, kidneys, intestines, testicles, and central nervous system. To date, the pathophysiological links between HEV infection and extrahepatic manifestations have not yet been established. Considering that HEV infects multiple types of cells, the direct effects of virus replication in peripheral tissues represent a plausible explanation for extrahepatic manifestations. In addition, since the immune response is crucial in the development of the disease, the immune characteristics of affected tissues should be revisited to identify commonalities explaining the effects of the virus. This review summarizes the most recent advances in understanding the virus biology and immune-privileged status of specific tissues as major elements for HEV replication in diverse organs. These discoveries may open avenues to explain the multiple extrahepatic manifestations associated with HEV infection and ultimately to design effective strategies for infection control.

Viral Hepatitis and Acute-on-Chronic Liver Failure

Acute-on-chronic liver failure (ACLF) is a potentially reversible syndrome that develops in patients with cirrhosis or with underlying chronic liver disease (CLD) and is characterized by acute decompensation, organ failure, and high short-term mortality. Hepatitis A and hepatitis E are major causes of ACLF. Hepatitis B may also cause ACLF through a flare of hepatitis B, acute infection, or reactivation. Besides supportive care, nucleoside/nucleotide analog therapy should also be initiated in this setting. Nonhepatotropic viruses may rarely also cause ACLF with the severe acute respiratory syndrome coronavirus 2 virus recently being identified with poorer outcomes in those with underlying CLD.

Hepatitis E Virus Infections: Epidemiology, Genetic Diversity, and Clinical Considerations

According to the World Health Organization, approximately 20 million people worldwide are infected annually with the hepatitis E virus (HEV). There are four main genotypes of HEV. Genotype 1 and genotype 2 are common in developing countries and are transmitted by contaminated water from a fecal-oral route. Genotype 3 and genotype 4 are common in developed countries and can lead to occasional transmission to humans via undercooked meat. Hepatitis E virus 1 and HEV3 can lead to fulminant hepatitis, and HEV3 can lead to chronic hepatitis and cirrhosis in immunocompromised patients. The majority of patients with HEV infection are asymptomatic and usually have spontaneous viral clearance without treatment. However, infection in immunocompromised individuals can lead to chronic HEV infection. Both acute and chronic HEV infections can have extrahepatic manifestations. No specific treatment is required for acute HEV infection, no treatment has been approved in chronic infection, and no HEV vaccine has been approved by the (United States) Food and Drug Administration. This review focuses on the molecular virology (HEV life cycle, genotypes, model systems, zoonosis), pathogenesis, clinical manifestation, and treatment of chronic HEV infection, especially in immunocompromised patients, to provide clinicians a better understanding of the global distribution of these infections and the significant effect they can have on immunocompromised patients.

Acalculous cholecystitis is a common extrahepatic manifestation of hepatitis E and suggests a more serious condition

BACKGROUND

This study aimed to understand the incidence and clinical significance of acalculous cholecystitis in patients with acute hepatitis E (HE).

PATIENTS AND METHODS

A single center enrolled 114 patients with acute HE. All patients underwent imaging of the gallbladder, and patients with gallstones and cholecystectomy were excluded.

RESULTS

Acalculous cholecystitis was found in 66 patients (57.89%) with acute HE. The incidence in males was 63.95%, which was significantly higher than in females (39.29%) (P = 0.022). The mean length of hospital stay and the incidence of spontaneous peritonitis in patients with cholecystitis (20.12 ± 9.43 days and 9.09%, respectively) were significantly higher than those in patients without cholecystitis (12.98 ± 7.26 days and 0%, respectively) (P < 0.001 and P = 0.032). Albumin, total bile acid, bilirubin, cholinesterase, and prothrombin activity in patients with cholecystitis were significantly inferior to those in patients without cholecystitis (P < 0.001, P < 0.001, P < 0.001, P < 0.001 and P = 0.003, respectively). After correction by multivariate analysis, albumin and total bile acid were found to be closely related to acalculous cholecystitis in HE.

CONCLUSION

Acalculous cholecystitis is very common in patients with acute HE, and may serve as a predictor of increased peritonitis, synthetic decompensation, and longer hospital stay.

Hepatitis E Virus (HEV) in Makkah, Saudi Arabia: A Population-Based Seroprevalence Study

BACKGROUND

The Hepatitis E virus (HEV) is a common cause of viral hepatitis worldwide. Little is known about the seroprevalence of HEV in the general population of Saudi Arabia.

METHODS

A community-based cross-sectional HEV seroprevalence study was conducted in Makkah, Saudi Arabia. Anti-HEV IgG antibodies were detected in sera using an in-house ELISA. The frequency of HEV sageerology and its correlation with demographic, and environmental factors were evaluated.

RESULTS

Enrollment consisted of 1329 individuals, ages ranged from 8 to 88 years, the mean age was 30.17 years, the median age was 28yrs, and the male: female ratio was 1.15. The overall seroprevalence was 23.8% (316/1329). Males had significantly higher seroprevalence than females (66.1 vs. 33.9%; p < 0.001). Seroprevalence had significant correlations with age, occupation, and lack of regular water supply and housing conditions.

CONCLUSIONS

This is the first HEV community-based seroprevalence study from Saudi Arabia. Results show that the HEV is endemic in Makkah and affects all age groups and occupations. HEV affects more males than females and those living in crowded accommodations without a regular supply of water. Further studies are required across all regions of Saudi Arabia to determine the country's seroprevalence of active or past infection using tests for HEV IgG, HEV IgM antibodies and/or HEV RNA and underlying determinants of transmission.

Seroprevalence and burden of hepatitis E viral infection among pregnant women in central Nigeria attending antenatal clinic at a Federal Medical Centre in Central Nigeria

Introduction

HEV infection may be life threatening in pregnant women and has been linked with 20–30% mortality, especially in the third trimester of pregnancy. HEV infection leads to elevated levels of preterm labour and other immunological parameters. It is vertically transmitted and could lead to poor feto-maternal outcomes. especially in fulminating viral hepatitis where both the mother and foetus could be lost. There is currently no known treatment or vaccine for HEV. There is therefore a need to study HEV seroprevalence and burden among vulnerable groups, such as pregnant women and their newborns in Nigeria, where maternal mortality is highly significant.

Methods

A total of 200 samples were collected from pregnant women attending antenatal clinic at Federal Medical Centre (FMC) Keffi, in central Nigeria, of which (156/200) samples were from HIV-negative pregnant women and (44/200) were from HIV-positive pregnant women, using a simple random sampling method.

Results

In total, 200 pregnant women [78.0% (156/200) HIV-negative pregnant women and 22.0% (44/200) HIV-positive pregnant women] were recruited for this study. The ages of the pregnant women ranged from 15-49 years, with a mean age of 26.4 years (± 6.23). The overall HEV IgG seropositivity in the study population was 31.5% (63/200); 95% CI (30-33).

Conclusion

This study highlighted an unexpectedly high seroprevalence of HEV and poor feto-maternal outcomes in pregnant women residing in a rural and urban setting of central Nigeria. The study showed that the inherently high HEV seropositivity and poor feto-maternal outcomes may not be attributed to HEV viral hepatitis only but may be a combination of extrinsic and intrinsic factors.