Hepatitis E seroprevalence in the Americas: A systematic review and meta-analysis

Epidemiological study of hepatitis E virus infection among students and workers in Hebei Province of China

AIMS

Hepatitis E caused by the hepatitis E virus (HEV) is prevalent worldwide. In China, considerable shifts in the epidemiology of hepatitis E have been observed over the last two decades, with ongoing changes in the prevalence of HEV.

METHODS

This study, in conjunction with the health examinations for students and workers, aims to estimate the seroprevalence and assess the risk factors of HEV infection in general population in Hebei province, China. Epidemiological information was collected using a specific questionnaire and blood samples were collected from each participant during the process of health examination. Anti-HEV IgG and IgM in sera were tested using the Wantai ELISA assay kits. Logistic regression modelling was used to identify associated risk factors.

RESULTS

The average positive rate of anti-HEV IgG in students (6-25 years) was 3.4%. One (0.2%) student was anti-HEV IgM positive, while also testing positive for IgG. The HEV seroprevalence was not related to students' gender, school, or family residence. In occupational populations, the overall seropositivity rate was 13.3% for anti-HEV IgG and 0.67% for IgM. HEV seropositivity increased significantly with age, ranging from 3.8% to 18.6% in age groups, and differed significantly among four occupation groups: farmers (17.6%), food supply workers (18.0%), other non-farm workers (14.7%) and healthcare workers (5.9%) (p = 0.002). Multivariable logistic analysis confirmed the significant correlations of seroprevalence with age and occupation.

CONCLUSIONS

The study found a low seroprevalence of HEV in children and young adults in Hebei Province, China. Advanced age correlates with higher seroprevalence in occupational populations, indicating an accumulation of HEV infection over time. Seroprevalence varied significantly among different occupation groups, suggesting the important role of occupational exposure for HEV infection.

Acute Hepatitis E Infection Associated With Deer Meat in the United States

Acute hepatitis E virus (HEV) infection in the United States of America (U.S.A) is low. However, seroprevalence rate is about of 6%. Most cases of HEV infection have been reported from travelers from endemic countries with poor sanitary conditions. Evidence of HEV as a zoonotic infection has been reported from developed countries from swine and wild animals including boar and deer. There is no reported case of direct transmission from wild game to humans in the U.S.A. We report a case of HEV from butchering of deer meat.

Higher Risk of HEV Transmission and Exposure among Blood Donors in Europe and Asia in Comparison to North America: A Meta-Analysis

Background and aims: The increasing number of diagnosed hepatitis E virus (HEV) infections in Europe has led to the implementation of the testing of blood products in various countries. Many nations have not yet implemented such screening. To assess the need for HEV screening in blood products worldwide, we conducted a systematic review and meta-analysis assessing HEV RNA positivity and anti-HEV seroprevalence in blood donors. Methods: Studies reporting anti-HEV IgG/IgM or HEV RNA positivity rates among blood donors worldwide were identified via predefined search terms in PubMed and Scopus. Estimates were calculated by pooling study data with multivariable linear mixed-effects metaregression analysis. Results: A total of 157 (14%) of 1144 studies were included in the final analysis. The estimated HEV PCR positivity rate ranged from 0.01 to 0.14% worldwide, with strikingly higher rates in Asia (0.14%) and Europe (0.10%) in comparison to North America (0.01%). In line with this, anti-HEV IgG seroprevalence in North America (13%) was lower than that in Europe (19%). Conclusions: Our data demonstrate large regional differences regarding the risk of HEV exposure and blood-borne HEV transmission. Considering the cost–benefit ratio, this supports blood product screening in high endemic areas, such as Europe and Asia, in contrast to low endemic regions, such as the U.S.

Hepatitis E Virus Research in Brazil: Looking Back and Forwards

Hepatitis E virus (HEV) has emerged as a public health concern in Brazil. From the first identification and characterization of porcine and human HEV-3 strains in the 2000s, new HEV subtypes have been identified from animal, human, and environmental isolates. As new potential animal reservoirs have emerged, there is a need to compile evidence on the zoonotic dissemination of the virus in animal hosts and the environment. The increasing amount of seroprevalence data on sampled and randomly selected populations must be systematically retrieved, interpreted, and considered under the One Health concept. This review focused on HEV seroprevalence data in distinct animal reservoirs and human populations reported in the last two decades. Furthermore, the expertise with experimental infection models using non-human primates may provide new insights into HEV pathogenesis, prevention, and environmental surveillance.

Ethnic differences in hepatitis A and E virus seroprevalence in patients attending the Emergency Department, Paramaribo, Suriname

BACKGROUND

Hepatitis A virus (HAV) and hepatitis E virus (HEV) have enteric modes of transmission and are common causes of acute hepatitis in low- and middle-income countries. HEV is also characterised as a zoonotic infection and is prevalent in high-income countries. Data on HAV and HEV prevalence in Suriname, a middle-income country in South America, are scarce.

METHODS

Serum samples of 944 and 949 randomly selected patients attending the Emergency Department at the Academic Hospital of Paramaribo, the capital of Suriname, were analysed for anti-HAV antibodies (anti-HAV) and anti-HEV antibodies (anti-HEV), respectively. Determinants of anti-HAV and anti-HEV positive serology were evaluated using multivariable logistic regression.

RESULTS

Anti-HAV prevalence was 58.3% (95% CI 55.4 to 61.4%) and higher prevalence was independently associated with belonging to the Tribal or Indigenous population and older age. Anti-HEV prevalence was 3.7% (95% CI 2.6 to 5.0%) and higher prevalence was associated with Tribal and Creole ethnicity and older age.

CONCLUSIONS

In Suriname, exposure to HAV is consistent with a very low endemic country and exposure to HEV was rare. Both viruses were more prevalent in specific ethnic groups. As anti-HAVantibodies were less frequently found in younger individuals, they could be susceptible to potential HAV outbreaks and might require HAV vaccination.

Hepatitis E virus infection in the United States: Seroprevalence, risk factors and the influence of immunological assays

In the United States (U.S.), a hepatitis E virus (HEV) seroprevalence between 6 and 21% has been described, with a decreasing trend. We aimed to investigate HEV infection in the U.S. population from 2009 to 2016, and examine the differences in seroprevalence using different assays. We used data from the National Health and Nutrition Examination Survey (NHANES-CDC) to estimate HEV seroprevalence and analyze demographic variables related to the infection. Additionally, we compared 4 serological tests used. The estimated HEV seroprevalence between 2009–2016 was 6.1% (95% CI: 5.6%-7.0%) for IgG and 1.02% (0.8%-1.2%) for IgM. Higher HEV IgG prevalences were found in older people, females, non-Hispanic Asians and those born outside of the U.S. The in-house immunoassay and the Wantai HEV-IgG ELISA presented the highest sensitivity values in the tested population. The highest specificity values corresponded to the DSI-EIA-ANTI-HEV-IgG assay. The kappa statistical values showed concordances no greater than 0.64 between the assays. HEV prevalence in our study was similar to previously reported, and a decline in the prevalence was observed through the NHANES assessments (from 1988 to 2016). The sensitivity and specificity of the assays varied widely, making comparisons difficult and highlighting the need to develop a gold standard assay.

Hepatitis A and E among immigrants and refugees in Central Brazil

OBJECTIVE

To estimate the prevalence of hepatitis A virus (HAV) and hepatitis E virus (HEV) among immigrants and refugees in Goiás, Central Brazil.

METHODS

Overall, 355 individuals were interviewed, and blood samples were tested for anti-HAV and anti-HEV IgG. Anti-HEV-positive samples were similarly tested for HEV RNA.

RESULTS

All participants were from Latin American countries, most of whom, young adult males. The overall anti-HAV IgG prevalence was 87.4% (95%CI: 83.5–90.4), of whom 94.9%, 75.6%, and 60% were from Haiti, Venezuela, and other Latin American countries, respectively (p < 0.001). Age above 19 years and more than 36 months residing in Brazil were associated with a higher prevalence of previous HAV and HEV infection, respectively. Of the children eligible for HAV vaccination according to the National Immunization Program, only eight (44%) had been vaccinated. The overall anti-HEV IgG prevalence was 6.5% (95%CI: 4.4–9.5). All anti-HEV IgG-positive individuals were Haitians, including a child born in Brazil. HEV RNA was detected in two of the anti-HEV IgG-positive samples.

CONCLUSION

The survey detected a high prevalence of anti-HAV and anti-HEV IgG among immigrants and refugees, and active HEV infection among some Haitian participants. Prevention measures are urgently required to interrupt enteric virus transmission in this emergent and vulnerable population.

Inactivation of Foodborne Viruses by UV Light: A Review

Viruses on some foods can be inactivated by exposure to ultraviolet (UV) light. This green technology has little impact on product quality and, thus, could be used to increase food safety. While its bactericidal effect has been studied extensively, little is known about the viricidal effect of UV on foods. The mechanism of viral inactivation by UV results mainly from an alteration of the genetic material (DNA or RNA) within the viral capsid and, to a lesser extent, by modifying major and minor viral proteins of the capsid. In this review, we examine the potential of UV treatment as a means of inactivating viruses on food processing surfaces and different foods. The most common foodborne viruses and their laboratory surrogates; further explanation on the inactivation mechanism and its efficacy in water, liquid foods, meat products, fruits, and vegetables; and the prospects for the commercial application of this technology are discussed. Lastly, we describe UV’s limitations and legislation surrounding its use. Based on our review of the literature, viral inactivation in water seems to be particularly effective. While consistent inactivation through turbid liquid food or the entire surface of irregular food matrices is more challenging, some treatments on different food matrices seem promising.

A systematic review and meta-analysis of hepatitis E virus (HEV) in wild boars

This systematic review and meta-analysis summarize the available information on Hepatitis E virus (HEV) -specific antibody seroprevalence and HEV RNA prevalence in wild boar, one of the most abundant game species worldwide. A literature search (CAB Abstracts, Web of Science, Embase and Scopus) was performed to find relevant peer-reviewed works published during the period 1990-2020. A random-effect model was carried out to calculate the pooled HEV-specific antibody seroprevalence and HEV RNA prevalence estimates with 95% confidence intervals, and I2 statistic was used to assess the heterogeneity of the data. Values by subgroups were compared according to the geographical area, age class (≤ 12 months old and > 12 months old), and sample type (bile, faeces, liver, meat/muscle, serum). Sixty-nine publications were selected, with the majority of the studies from Southern Europe (n = 27). The pooled HEV-specific antibody seroprevalence in wild boar was 28% (CI95% 23-34) and the HEV RNA prevalence 8% (CI95% 6-10). The analysis highlighted a significant heterogeneity among the estimates from the included studies (I2 = 98% and I2 = 95% for HEV-specific antibody seroprevalence and viral prevalence respectively). The moderator analysis indicated a statistically significant difference (p-value = 0.03) for the HEV RNA prevalence according to the sample type, with the highest value in bile (17%, CI95% 9-27), followed by liver (10%, CI95% 7-14), serum (7%, CI95% 4-10), faeces (5%, CI95% 2-9), and meat/muscle (3%, CI95% 0.04-10). Finally, the HEV RNA prevalence in Europe (8.7, CI95% 6.7-11) was significantly (p-value = 0.04) higher than in Asia (4, CI95% 0.6-8). The analysis highlights the important role of wild boar in the epidemiology of HEV.

Systematic Review of Hepatitis E Virus in Brazil: A One-Health Approach of the Human-Animal-Environment Triad

Simple Summary

Hepatitis E virus (HEV) is an important causative agent of acute and chronic hepatitis worldwide. Originally identified in epidemics associated with flooding in Asia, it nowadays shows very distinct genetic and epidemiological patterns. While HEV genotypes (HEV-) 1 and 2 are associated with the original outbreaks (waterborne diseases), HEV-3 and HEV-4 present a zoonotic pattern (associated with consumption of meat from infected animals), HEV-5 and 6 have been found only in wild boar in Japan, and HEV-7 and 8 have been detected in camels and dromedary seldom affecting humans. Brazil, with a precarious sanitary structure and being an important world meat producer, was the focus of this study in order to identify patterns of occurrence of HEV. After reviewing scientific studies, it was identified that the only genotype found in Brazil is HEV-3 and the area where there were more reports was the South region of the country. This is the region that produces more pork. These results indicate that HEV-3 is widespread in the country and sanitary surveillance is essential in the national production of pigs, as well as the implementation of monitoring protocols in hospitals.

Abstract

Brazil is the fifth largest country in the world with diverse socioeconomic and sanitary conditions, also being the fourth largest pig producer in the world. The aim of the present systematic review was to collect and summarize all HEV published data from Brazil (from 1995 to October 2020) performed in humans, animals, and the environment, in a One Health perspective. A total of 2173 papers were retrieved from five search databases (LILACs, Mendeley, PubMed, Scopus, and Web of Science) resulting in 71 eligible papers after application of exclusion/inclusion criteria. Data shows that HEV genotype 3 (HEV-3) was the only retrieved genotype in humans, animals, and environment in Brazil. The South region showed the highest human seroprevalence and also the highest pig density and industry, suggesting a zoonotic link. HEV-1 and 2 were not detected in Brazil, despite the low sanitary conditions of some regions. From the present review we infer that HEV epidemiology in Brazil is similar to that of industrialized countries (only HEV-3, swine reservoirs, no waterborne transmission, no association with low sanitary conditions). Hence, we alert for the implementation of HEV surveillance systems in swine and for the consideration of HEV in the diagnostic routine of acute and chronic hepatitis in humans.

Seroprevalence of hepatitis E virus in risk populations and blood donors in a referral hospital in the south of Brazil

The prevalence of anti-hepatitis E virus (HEV) antibodies has a high heterogeneity worldwide. South American data are still scarce. The aim of this study was to evaluate the prevalence of HEV in populations at risk in comparison to blood donors (BD). A cross-sectional study was carried out in adults of different risk populations including crack users (CK), residents in a low income area (LIA), cirrhotic (CIR) and liver transplant patients (LT) compared with BD. The WANTAI HEV ELISA test was used and real-time PCR (in-house for screening and ALTONA as confirmatory test) for HEV RNA screening. A total of 400 participants were included. Anti-HEV IgG was positive in 19.5% of the total sample, reaching the highest rate in the CIR group, 22.5%, followed by CK, LT, and LIA (20%, 18.7%, and 17.5%, respectively). The prevalence found in BD individuals was of 18.7% (p = NS). Anti-HEV IgM was positive in only 1.5% of the sample (6/400). No blood or stools samples were positive for HEV RNA. The seroprevalence reported is among the highest rates ever found in Brazil. Considering the intense diagnostic investigation, data show that HEV circulation is more common that might be expected in our country.

Hepatitis E seroprevalence and viremia rate in immunocompromised patients: a systematic review and meta-analysis

BACKGROUND AND AIMS

Hepatitis E is an infectious disease of the liver caused by the hepatitis E virus (HEV). Immunocompromised patients present a particular risk group, as chronification of hepatitis E leading to life-threatening cirrhosis occurs when these patients are infected. Therefore, this study aims to estimate and compare the anti-HEV seroprevalence and the rate of HEV RNA positivity in transplant recipients and patients with human immunodeficiency virus (HIV).

METHODS

This systematic review and meta-analysis involved a literature search (PubMed, Scopus; 1,138 studies) including 120 studies from 1996 to 2019, reporting anti-HEV seroprevalence and/or HEV-RNA positivity. Statistical analysis was performed using a linear mixed-effects meta regression model.

RESULTS

Anti-HEV seroprevalence in 14 626 transplant recipients ranged from 6% (95% CI: 1.9-17.2) to 29.6% (95% CI: 21.6-39.) in different commercially available assays and did not differ significantly compared to 20 825 HIV positive patients (range: 3.5% (95% CI: 0.9-12.8) - 19.4% (95% CI: 13.5-26.9). In contrast, HEV-RNA positivity rate was significantly higher in transplant recipients than in HIV positive patients (1.2% (95% CI: 0.9-1.6) vs 0.39% (95% CI: 0.2-0.7); P-value = 0.0011).

CONCLUSION

Anti-HEV seroprevalence did not differ significantly between transplant recipients and HIV positive patients. Interestingly, rates of HEV-RNA positivity, indicating ongoing infection, were significantly higher in transplant recipients. These findings demonstrate that transplant patients have an elevated risk of chronic infection in comparison to HIV patients at comparable risk of HEV-exposure.

Prognostic Significance of End-Stage Liver Diseases, Respiratory Tract Infection, and Chronic Kidney Diseases in Symptomatic Acute Hepatitis E

Symptomatic hepatitis E virus (HEV) infection is sporadic, and usually occurs in a limited number of infected patients, which hinders the investigation of risk factors for clinical outcomes in patients with acute HEV infection. A retrospective cohort study enrolling 1913 patients with symptomatic acute hepatitis E in Beijing 302 Hospital from January 1, 2001 to December 31, 2018 was conducted. The baseline characteristics, clinical features and laboratory data of these HEV infection cases were analyzed. Albumin (ALB), platelet (PLT), alanine aminotransferase (ALT), total bilirubin (T-BiL), international normalized ratio (INR) and serum creatinine (SCR) levels, along with the model for end-stage liver disease (MELD) score, hospitalization days, co-morbidity number and mortality were taken as major parameters for comparing the clinical manifestations in our study. We found that not all pre-existing chronic liver diseases exacerbate clinical manifestations of acute hepatitis E. Alcoholic hepatitis, fatty liver hepatitis, hepatic cyst, drug-induced hepatitis and hepatocellular carcinoma were not significantly associated with mortality of HEV patients. Among all of the comorbidities, end-stage liver diseases (ESLDs, including ascites, cirrhosis, hepatic coma and hepatorenal syndrome), respiratory tract infection and chronic kidney diseases (CKDs, including renal insufficiency and renal failure) were found to remarkably increase the mortality of patients with symptomatic HEV infection. Furthermore, the severity evaluation indexes (SEI), such as MELD score, duration of hospital stay, and co-morbidity number in HEV patients with underlying comorbidities were much worse than that of their counterparts without relevant comorbidities.

The histologic presentation of hepatitis E reflects patients' immune status and pre-existing liver condition

Infection with the hepatitis E virus (HEV) is one of the main causes of acute hepatitis worldwide. Given that, the histopathology of hepatitis E is relatively poorly characterized, and it is unclear what exactly determines its remarkable variability. The aim of our study was a systematic analysis of hepatitis E histology, especially with regard to the clinical setting. Fifty-two liver samples (48 biopsies, 1 liver explant, 3 autopsy livers) from 41 patients with molecularly proven hepatitis E (28 HEV genotype (gt) 3, three gt 1, one gt 4 and 9 undetermined gt) were systematically evaluated for 33 histopathologic features. Following one approach, the biopsies were assigned to one of five generic histologic patterns. In another approach, they were subjected to hierarchical clustering. We found that 23/41 (56%) patients were immunocompromised, whereas 18 (44%) had no known immunosuppression. Five patients (12%) had pre-existing liver disease (LD). The histopathologic spectrum ranged from almost normal to acute, chronic, and steato-hepatitis to subtotal necrosis, and was thus distributed across all five generic patterns. Hierarchical clustering, however, identified three histopathologic clusters (C1-C3), which segregated along the immune status and pre-existing LD: C1 comprised mostly patients with pre-existing LD; histology mainly reflected the respective LD without pointing to the additional hepatitis E. C2 comprised mostly immunocompetent patients; histology mainly displayed florid hepatitis. C3 comprised mostly immunocompromised patients; histology mainly displayed smoldering hepatitis. Accordingly, C1-C3 differed markedly with respect to their clinical and histopathologic differential diagnoses. Hierarchical clustering suggests three groups with distinct histopathologies, indicating biologically different manifestations of hepatitis E. The association of histopathologic changes with the patient's immune status and pre-existing LD plausibly explains the diversity of hepatitis E histopathology, and suggests that these factors are the crucial underlying determinants. We expect our results to improve patient management by guiding the clinico-pathologic diagnosis of hepatitis E.

Hepatitis E virus seroprevalence in patients with chronic hepatitis C at a university hospital in Brazil

Aim: We investigated the prevalence of anti-hepatitis E virus (HEV) antibodies in patients with chronic hepatitis C and the relationship with liver injury stage. Materials & methods: In total, 451 patients were included and the presence of anti-HEV antibodies was evaluated by ELISA. Results: Anti-HEV IgG antibodies were detected in 45 (10.0%) patients and anti-HEV IgM were detected in two IgG-positive patients (4.4%). The distributions of liver fibrosis, steatosis, inflammatory activity, homeostasis model assessment of insulin resistance and liver enzyme levels were similar between HEV-positive and HEV-negative patients. However, HEV-positive patients had a higher mean age (p = 0.030). The seroprevalence by age group increased from 2.2 (18–30 years) to 53.3% (>60 years). HEV infection was not related to advanced fibrosis. Conclusion: This investigation showed that the seroprevalence of HEV among patients with chronic hepatitis C is similar to that of blood donors in the same region.

Evidence for Increased Inflammatory Cytokine Profile in Hepatitis E Virus-Infected Obese Patients: Implications for Chronic Liver Disease

We aimed to characterize the contribution of hepatitis E virus (HEV) in perpetuating the cytokine-mediated inflammatory setting related to liver damage in the context of obesity. Herein, serum samples from patients with liver disease were retrospectively analyzed and categorized as normal-weight patients (NW), overweight patients (OW), obese patients (ObP), and high alcohol consumer patients (HAC), and biochemical, anthropometrical, and transient elastography measurements were obtained. The positivity for immunoglobulin M (IgM) and immunoglobulin G (IgG) anti-HEV antibodies in samples was determined by enzyme-linked immunosorbent assay. Available samples from ObP were tested by reverse transcription-nested polymerase chain reaction for the presence of HEV-RNA. Cytokine profile in the serum of ObP was identified using a multiplexed immune assay. Globally, the highest frequency of IgG anti-HEV was found in ObP (57.5%), followed by HAC (20%), OW (15%), and NW (7.5%). A strong association between HEV serology and obesity was found (odds ratio = 4.21, confidence interval = 1.91.9.27) with a cutoff of 29.3 kg/m² (area under curve [AUC] = 0-66; p = 0.003) and, a 23.7% of available samples of ObP provided amplification of HEV genome. Cytokine analysis revealed significantly higher levels of proinflammatory cytokines (interleukin [IL]-12, interferon [IFN]-γ, and IL-1β) in IgG anti-HEV-positive ObP than in IgG anti-HEV-negative ObP. Moreover, a high proportion of patients with positive serology showed advanced liver damage. In conclusion, the high percentage of anti-HEV antibodies and viral RNA detection in the setting of an excess of fat, along with an associated proinflammatory cytokine profile found in IgG anti-HEV-positive ObP with more severe liver disease, support an interplay between HEV and obesity.

Hepatitis E in Latin America

Hepatitis E virus produces an emerging health problem, knowledge about epidemiology of hepatitis E virus infections in the USA and Latin America is still limited. The wide-ranging clinical manifestations lead to an extensive underestimation of the global seroprevalence. Clinical and diagnostic accuracy are critical to improve patient management.

The global epidemiology of hepatitis E virus infection: A systematic review and meta-analysis

BACKGROUND AND AIMS

Hepatitis E virus (HEV), as an emerging zoonotic pathogen, is a leading cause of acute viral hepatitis worldwide, with a high risk of developing chronic infection in immunocompromised patients. However, the global epidemiology of HEV infection has not been comprehensively assessed. This study aims to map the global prevalence and identify the risk factors of HEV infection by performing a systematic review and meta-analysis.

METHODS

A systematic searching of articles published in Medline, Embase, Web of science, Cochrane and Google scholar databases till July 2019 was conducted to identify studies with HEV prevalence data. Pooled prevalence among different countries and continents was estimated. HEV IgG seroprevalence of subgroups was compared and risk factors for HEV infection were evaluated using odd ratios (OR).

RESULTS

We identified 419 related studies which comprised of 1 519 872 individuals. A total of 1 099 717 participants pooled from 287 studies of general population estimated a global anti-HEV IgG seroprevalence of 12.47% (95% CI 10.42-14.67; I²  = 100%). Notably, the use of ELISA kits from different manufacturers has a substantial impact on the global estimation of anti-HEV IgG seroprevalence. The pooled estimate of anti-HEV IgM seroprevalence based on 98 studies is 1.47% (95% CI 1.14-1.85; I²  = 99%). The overall estimate of HEV viral RNA-positive rate in general population is 0.20% (95% CI 0.15-0.25; I²  = 98%). Consumption of raw meat (P = .0001), exposure to soil (P < .0001), blood transfusion (P = .0138), travelling to endemic areas (P = .0244), contacting with dogs (P = .0416), living in rural areas (P = .0349) and receiving education less than elementary school (P < .0001) were identified as risk factors for anti-HEV IgG positivity.

CONCLUSIONS

Globally, approximately 939 million corresponding to 1 in 8 individuals have ever experienced HEV infection. 15-110 million individuals have recent or ongoing HEV infection. Our study highlights the substantial burden of HEV infection and calls for increasing routine screening and preventive measures.

Hepatitis E: an expanding epidemic with a range of complications

BACKGROUND

Hepatitis E virus (HEV) is a common cause of viral hepatitis worldwide. Previously considered a disease of the developing world, it is increasingly recognized that locally acquired HEV infection is common in industrialized countries.

OBJECTIVES

The aim was to highlight the changing epidemiology of HEV infection, particularly in the developed world, and inform clinicians of the diverse clinical presentations and extra-hepatic complications associated with the virus.

SOURCES

References for this review were identified through searches of MEDLINE/PubMed, and Google Scholar, up to January 2020. Searches were restricted to articles published in English.

CONTENT

Hepatitis E virus is an under-recognized, emerging pathogen with important implications for public health in both the developing and developed world. The number of cases reported in resource-rich settings is increasing, in part due to improved case ascertainment but also as a result of increased incidence in some countries. The reasons behind these epidemiological shifts are not currently known. Chronic HEV infection has been reported in immunocompromised patients. A range of extra-hepatic manifestations have also been reported, most notably neurological and renal complications. There is evidence to suggest a causal link with Guillain-Barré syndrome, neuralgic amyotrophy and encephalitis/myelitis. Glomerular disease has been reported in the context of both acute and chronic infection.

IMPLICATIONS

HEV should be included in non-invasive liver screens and considered in the differentials for patients presenting with alanine aminotransferase elevation, suspected drug-induced liver injury or decompensated liver disease. Any patients with acute neurological injury and deranged liver function should be tested for hepatitis E, and all patients presenting with Guillain-Barré syndrome or neuralgic amyotrophy should be tested regardless of liver enzymes. Immunocompromised patients with persistently raised liver enzymes should be tested with molecular techniques and offered annual routine screening.

A Systematic Review of the Extra-Hepatic Manifestations of Hepatitis E Virus Infection

Hepatitis E virus (HEV) is a non-enveloped, positive-sense, single-stranded RNA icosahedral virus belongs to the genus Orthohepevirus within the Hepeviridae family. HEV infection can be asymptomatic, or it can cause icteric or fulminant hepatitis. Off late, there have been a number of publications reporting the extra-hepatic manifestations of HEV infection, and this systematic review is aimed at summarizing the available evidence in this regard. Two independent investigators searched PubMed, PubMed Central and Embase databases using the search string "(((hepatitis E) AND (Extrahepatic OR Extra-Hepatic))) OR ((Hepatitis E) AND (Neurology OR Cardiology OR Respiratory OR Lung OR Gastrointestinal OR musculoskeletal OR immunology OR pulmonary)) Filters: Abstract availability, English language, and Human studies". The extra-hepatic manifestations reported in each of the selected articles were classified and reported as neurological, cardiovascular, and hematological and miscellaneous manifestations. The total number of various manifestations reported in our study were n = 324. These include neurological manifestations (n = 178/324 (54.94%)), cardiovascular and hematological manifestations (n = 113/324 (34.88%)), gastro-intestinal/pancreaticobiliary manifestations (n = 24/324 (7.41%)) and other rarer manifestations involving systems such as renal (n = 4/324; 1.24%), endocrine (n = 1/324; 0.31%), dermatology (n = 1/324; 0.31%), respiratory (n = 1/324; 0.31%), muscular (n = 1/324; 0.31%) and immune system (n = 1/324; 0.31%). Thus, HEV can have extra-hepatic manifestations affecting any system of the human body. Further research is needed to elucidate the underlying pathophysiological manifestations of these extra-hepatic manifestations and to prove causal association with HEV.

Hepatitis E: a largely underestimated, emerging threat

Hepatitis E virus has two distinct clinical and epidemiological patterns based on the varying genotypes. Genotypes 3 and 4 cause widespread, sporadic infection in high-income countries and are emerging as the most common type of viral hepatitis in much of Europe. These infections carry significant morbidity and mortality in the growing numbers of immunosuppressed patients or in patients with established liver disease. Furthermore the growing extra-hepatic associations of the virus, including neurological and kidney injury, suggest that it may have been misnamed as a 'hepatitis' virus. This review explores current understanding of the epidemiology, virology and clinical presentations of hepatitis E infection and identifies vulnerable patient groups, who are at serious risk from infection. Guidance is offered regarding the diagnosis, treatment and prevention of this growing public health hazard.

Clinicopathologic features and pathologic diagnosis of hepatitis E

Infection with the hepatitis E virus (HEV) is one of the most common causes, if not the most common, of acute hepatitis worldwide. In the last decade, we have learned that, in addition to the endemically and epidemically occurring form of hepatitis E, which is predominantly transmitted by contaminated drinking water and constitutes a significant health problem in resource-poor countries, there is a globally existing form of hepatitis E, which is a zoonosis and as such is primarily transmitted by the consumption of contaminated meat products. Although in most cases hepatitis E is subclinical or mild and self-limiting, pregnant women and patients with liver cirrhosis may have severe, occasionally even fatal disease, and immunocompromised individuals may develop chronic hepatitis E. Considering the substantial global health burden caused by HEV infection, it is surprising how limited our knowledge of hepatitis E pathology still is. In this article, we describe localization studies on HEV infection and discuss their implications for everyday diagnostics. Furthermore, we outline and discuss the spectrum of histologic changes, which can be found in HEV infection in various clinical contexts.

The Clinical Perspective on Hepatitis E

Every year, there are an estimated 20 million hepatitis E virus (HEV) infections worldwide, leading to an estimated 3.3 million symptomatic cases of hepatitis E. HEV is largely circulating in the west and is associated with several hepatic and extrahepatic diseases. HEV Genotype 1 and 2 infections are waterborne and causative for epidemics in the tropics, while genotype 3 and 4 infections are zoonotic diseases and are mainly transmitted by ingestion of undercooked pork in industrialized nations. The clinical course of these infections differs: genotype 1 and 2 infection can cause acute illness and can lead to acute liver failure (ALF) or acute on chronic liver failure (ACLF) with a high mortality rate of 20% in pregnant women. In contrast, the majority of HEV GT-3 and -4 infections have a clinically asymptomatic course and only rarely lead to acute on chronic liver failure in elderly or patients with underlying liver disease. Immunosuppressed individuals infected with genotype 3 or 4 may develop chronic hepatitis E, which then can lead to life-threatening cirrhosis. Furthermore, several extra-hepatic manifestations affecting various organs have been associated with ongoing or previous HEV infections but the causal link for many of them still needs to be proven. There is no approved specific therapy for the treatment of acute or chronic HEV GT-3 or -4 infections but off-label use of ribavirin has been demonstrated to be safe and effective in the majority of patients. However, in approximately 15% of chronically HEV infected patients, cure is not possible.

Why all blood donations should be tested for hepatitis E virus (HEV)

Background

Hepatitis E is a liver disease caused by a small RNA virus known as hepatitis E virus (HEV). Four major genotypes infect humans, of which genotype 1 and 2 (HEV-1, HEV-2) are endemic mainly in Asia and responsible for waterborne epidemics. HEV-3 and HEV-4 are widely distributed in pigs and can be transmitted to humans mainly by undercooked meat, and contact with pigs. HEV-3 is the main genotype in industrialised countries with moderate climate conditions and object of this debate.

Main text

Whereas an HEV-3 infection in healthy humans is mostly asymptomatic, HEV-3 can induce chronic infection in immunocompromised individuals and acute-on-chronic liver failure (ACLF) in patients with underlying liver diseases. The number of reported cases of HEV-infections in industrialised nations increased significantly in the last years. Since HEV-3 has been transmitted by blood transfusion to other humans, testing of blood donors has been introduced or introduction is being discussed in some industrialised countries. In this article we summarise the arguments in favour of testing all blood donations for HEV-3.

Conclusion

The number of HEV infection in the population and the possibility of HEV transmission by blood transfusion are increasing. Transmission by blood transfusion can be dangerous for the recipients considering their immunosuppressive status, underlying disease or other circumstances requiring blood transfusion. This argues in favour of testing all blood donations for HEV-3 to prevent transmission.

Prevalence of hepatitis E virus infection in multiple transfused Brazilian patients with thalassemia and sickle cell disease

Hepatitis E virus (HEV) is a leading cause of acute hepatitis worldwide. The virus is acquired by fecal-oral route; however, it can also be transmitted by blood transfusion. The objective of the study was to examine anti-HEV immunoglobulin G and HEV RNA prevalence in multiple transfused patients with thalassemia and sickle cell disease (SCD), and in blood donors. The HEV seroprevalence in the patients was 13% (20% in thalassemics; 7.7% in SCD), and 11% in blood donors. No positive result for HEV RNA was obtained. This is a pioneer study examining HEV circulation in Brazilian patients with hemoglobinopathies.

Hepatitis E virus (HEV)-The Future

Hepatitis (HEV) is widely distributed in pigs and is transmitted with increasing numbers to humans by contact with pigs, contaminated food and blood transfusion. The virus is mostly apathogenic in pigs but may enhance the pathogenicity of other pig viruses. In humans, infection can lead to acute and chronic hepatitis and extrahepatic manifestations. In order to stop the emerging infection, effective counter-measures are required. First of all, transmission by blood products can be prevented by screening all blood donations. Meat and sausages should be appropriately cooked. Elimination of the virus from the entire pork production can be achieved by sensitive testing and elimination programs including early weaning, colostrum deprivation, Caesarean delivery, embryo transfer, treatment with antivirals, protection from de novo infection, and possibly vaccination. In addition, contaminated water, shellfish, vegetables, and fruits by HEV-contaminated manure should be avoided. A special situation is given in xenotransplantation using pig cells, tissues or organs in order to alleviate the lack of human transplants. The elimination of HEV from pigs, other animals and humans is consistent with the One Health concept, preventing subclinical infections in the animals as well as preventing transmission to humans and disease.

Risk analysis and seroprevalence of HEV in people living with HIV/AIDS in Brazil

Acute Hepatitis E virus (HEV) infection in people living with HIV/AIDS (PLHA) can lead to fulminant hepatic failure, cirrhosis and death. The prevalence of anti-HEV antibodies within this group varies according to the geographical area. However, in South America, studies concerning the detection of HEV in PLHA are rare. Here, we investigated the presence of HEV by serological and molecular detection and evaluated the risk factors associated with infection in PLHA in Pernambuco state, Brazilian Northeast. Serological and molecular detection of HEV was performed in 366 samples of PLHA by ELISA for anti-HEV IgG and RT-PCR, respectively. Anti-HEV IgG prevalence was 4.1% (15/366) and no HEV RNA was detected. Concerning the risk factors, we evaluated, in multivariable analysis, age, years of school, sexual orientation, oral-anal sex, use of injectable drugs and piped water. Among them, only piped water availability could be associated with the HEV infection in PLHA (OR: 0.08; CI 95%: 0.01-0.66; p = 0.0182). This study showed for the first time the association of piped water as protection factor for HEV infection in PLHA. Finally, this is also the first report of HEV seroprevalence in PLHA in the Northeast Brazil.

Life cycle and morphogenesis of the hepatitis E virus

Hepatitis E virus (HEV) is transmitted primarily via contaminated water and food by the fecal oral route and causes epidemics in developing countries. In industrialized countries, zoonotic transmission of HEV is prevalent. In addition, HEV is the major cause of acute hepatitis in healthy adults and can cause chronic hepatitis in immunocompromised patients, with pregnant HEV-infected women having increased mortality rates of approximately 25%. HEV was once an understudied and neglected virus. However, in recent years, the safety of blood products with respect to HEV has increasingly been considered to be a public health problem. The establishment of HEV infection models has enabled significant progress to be made in understanding its life cycle. HEV infects cells via a receptor (complex) that has yet to be identified. The HEV replication cycle is initiated immediately after the (+) stranded RNA genome is released into the cell cytosol. Subsequently, infectious viral particles are released by the ESCRT complex as quasi-enveloped viruses (eHEVs) into the serum, whereas feces and urine contain only nonenveloped infectious viral progeny. The uncoating of the viral envelope takes place in the biliary tract, resulting in the generation of a nonenveloped virus that is more resistant to environmental stress and possesses a higher infectivity than that of eHEV. This review summarizes the current knowledge regarding the HEV life cycle, viral morphogenesis, established model systems and vaccine development.

Characterization of a quasi-enveloped, fast replicating hepevirus from fish and its use as hepatitis E virus surrogate

Hepatitis E virus (HEV) is an emerging concern for the safety of plasma-derived medicinal products. The lack of an efficient cell culture system hampers the studies on HEV biology as well as validation studies to test the capacity of virus reduction steps to clear HEV. Hence, a surrogate hepevirus that can efficiently replicate in cell culture is needed. Cutthroat trout virus (CTV) is a non-pathogenic fish hepevirus, which can replicate in cell culture to high titers. Under interferon inhibition, CTV replication reached up to 5 × 10⁷ genome equivalents per μL in 4-5 days. The intracellular CTV progeny was already lipid-associated, suggesting that the envelope is acquired from intracellular membranes. Transmission electron microscopy of purified quasi-enveloped virus revealed exosome-like structures with an average size of 40 nm, in contrast to 27-34 nm for the non-enveloped virus. The quasi-enveloped virus was significantly less infectious than the non-enveloped virus. Assays based on quantitative RT-PCR, immunofluorescence and immunocytochemistry were established to evaluate virus inactivation. Cold ethanol fractionation removed 3.0 log of CTV and pasteurization of human albumin inactivated more than 3.7 log to below the limit of detection. Similar to HEV, virus replication was promoted in the presence of 17β-estradiol, an effect that can contribute to the understanding of the exacerbated virulence of HEV in pregnant women. These results together reveal substantial similarities between the human and fish HEV and validate CTV as a practical virus model to use in some applications for evaluating the HEV reduction capacity of biological manufacturing process steps.