Occurrence of hepatitis E virus infection in acute hepatitis in Thailand

Systematic review and meta-analysis of hepatitis E seroprevalence in Southeast Asia: a comprehensive assessment of epidemiological patterns

The burden of hepatitis E in Southeast Asia is substantial, influenced by its distinct socio-economic and environmental factors, as well as variations in healthcare systems. The aim of this study was to assess the pooled seroprevalence of hepatitis E across countries within the Southeast Asian region by the UN division.The study analyzed 66 papers across PubMed, Web of Science, and Scopus databases, encompassing data from of 44,850 individuals focusing on anti-HEV seroprevalence. The investigation spanned nine countries, excluding Brunei and East Timor due to lack of data. The pooled prevalence of anti-HEV IgG was determined to be 21.03%, with the highest prevalence observed in Myanmar (33.46%) and the lowest in Malaysia (5.93%). IgM prevalence was highest in Indonesia (12.43%) and lowest in Malaysia (0.91%). The study stratified populations into high-risk (farm workers, chronic patients) and low-risk groups (general population, blood donors, pregnant women, hospital patients). It revealed a higher IgG-28.9%, IgM-4.42% prevalence in the former group, while the latter group exhibited figures of 17.86% and 3.15%, respectively, indicating occupational and health-related vulnerabilities to HEV.A temporal analysis (1987-2023), indicated an upward trend in both IgG and IgM prevalence, suggesting an escalating HEV burden.These findings contribute to a better understanding of HEV seroprevalence in Southeast Asia, shedding light on important public health implications and suggesting directions for further research and intervention strategies.Key pointsResearch QuestionInvestigate the seroprevalence of hepatitis E virus (HEV) in Southeast Asian countries focusing on different patterns, timelines, and population cohorts.FindingsSporadic Transmission of IgG and IgM Prevalence:• Pooled anti-HEV IgG prevalence: 21.03%• Pooled anti-HEV IgM prevalence: 3.49%Seroprevalence among specific groups:High-risk group (farm workers and chronic patients):• anti-HEV IgG: 28.9%• anti-HEV IgM: 4.42%Low-risk group (general population, blood donors, pregnant women, hospital patients):• anti-HEV IgG: 17.86%• anti-HEV IgM: 3.15%Temporal Seroprevalence of HEV:Anti-HEV IgG prevalence increased over decades (1987-1999; 2000-2010; 2011-2023): 12.47%, 18.43%, 29.17% as an anti-HEV IgM prevalence: 1.92%, 2.44%, 5.27%ImportanceProvides a comprehensive overview of HEV seroprevalence in Southeast Asia.Highlights variation in seroprevalence among different population groups.Reveals increasing trend in HEV seroprevalence over the years.Distinguishes between sporadic and epidemic cases for a better understanding of transmission dynamics.

A Comparison of Clinical Manifestations and Outcomes between Acute Sporadic Hepatitis A and Hepatitis E Infections in Thailand

Hepatitis A virus (HAV) and hepatitis E virus (HEV) infections often present as acute hepatitis with prodromal symptoms. These infections, transmitted via the oral-enteral route, constitute significant public health challenges, particularly in developing countries with subpar sanitary systems. The aim of the study was to describe the clinical manifestations, laboratory findings, and outcomes of hepatitis A and hepatitis E infections in Thailand. We conducted a retrospective chart review and analysis of 152 patients diagnosed with acute hepatitis A or hepatitis E from January 2007 to August 2018 at Siriraj Hospital. The hepatitis E cohort was older with a greater prevalence of comorbidities (hypertension, diabetes mellitus, chronic kidney disease, chronic hepatitis B, and post-kidney transplantation status) than the hepatitis A cohort. While the majority of hepatitis A patients presented with fever (98%) and jaundice (96%), these symptoms were less pronounced in hepatitis E patients. Furthermore, hepatitis A patients exhibited significantly higher aminotransferase and total bilirubin levels. However, clinical outcomes, such as hospitalization rates, progression to acute liver failure, and mortality, were comparable across both groups. In conclusion, although the clinical manifestations of hepatitis A and hepatitis E were similar, fever and jaundice were more prevalent and aminotransferase and bilirubin levels were higher in the HAV-infected group.

Meta-analysis and moderator analysis of the seroprevalence of hepatitis E in South-Eastern Asia

By 2030, the World Health Organization wants to decrease viral hepatitis incidence and mortality by 90% and 65%, respectively. One of the agents responsible for the increased burden of viral hepatitis is the hepatitis E virus (HEV). This emerging pathogen is prevalent worldwide causing both acute and chronic infection. The rising risk profile of HEV has become a source of increased global public health concern. Despite this challenge, South-Eastern Asia (SEA), where many at-risk people are found, lacks uniform HEV prevalence data. Therefore, a meta-analysis was conducted to assess the overall prevalence of hepatitis E in SEA. Using R statistical software, a random effect model was used to estimate the logit-transformed prevalence. Moderator analyses were used to investigate the potential sources of variation. Thirty-two studies comprising 29,944 with 6806 anti-HEV antibody-positive individuals were evaluated. The overall HEV seroprevalence in SEA was 21% (95% confidence interval [CI]: 17-27) with high heterogeneity. At the country level, Laos has the highest prevalence estimate of 39% (CI: 16-69). Also, the studied population, year of publication, duration of sampling, and diagnostic method are significant HEV prevalence predictors accounting for 22.61% of the observed heterogeneity. The high HEV prevalence found in this study necessitates coordinated national and regional efforts to combat this emerging disease.

Prevalence and clinical correlation of hepatitis E virus antibody in the patients' serum samples from a tertiary care hospital in Thailand during 2015-2018

Background

Prevalence and incidence of hepatitis caused by HEV infection are usually higher in developing countries. This study demonstrated the HEV seroprevalence and incidence of HEV infection in patients with clinical hepatitis in a tertiary hospital in Thailand.

Methods

A laboratory-based cross-sectional study was conducted using 1106 serum samples from patients suspected of HEV infection sent to the Serology laboratory, Siriraj Hospital, for detecting HEV antibodies during 2015–2018. Prevalence of anti-HEV IgG and IgM antibodies in general patients, including organ transplant recipients and pregnant women in a hospital setting, were determined using indirect enzyme-linked immunosorbent assay (ELISA) kits. Comparison of laboratory data between groups with different HEV serological statuses was performed.

Results

HEV IgG antibodies were detected in 40.82% of 904 serum samples, while HEV IgM antibodies were detected in 11.75% of 1081 serum samples. Similar IgG and IgM antibody detection rates were found in pregnant women. Interestingly, anti-HEV IgM antibodies were detected in 38.5% of patients who underwent organ transplantation. Patients who tested positive for anti-HEV IgM antibodies had higher alanine aminotransferase levels than those who had not. In contrast, patients who tested positive for anti-HEV IgG had more elevated levels of total bilirubin than those who tested negative.

Conclusions

HEV seroprevalence and incidence in patients with clinical hepatitis were relatively high in the Thai population, including the pregnancy and organ transplant subgroups. The results potentially benefit the clinicians in decision-making to investigate HEV antibodies and facilitating proper management for patients.

A systematic review of the epidemiology of Hepatitis E virus infection in South - Eastern Asia

Hepatitis E virus (HEV) infection is an emerging zoonotic viral disease, with an increasingly international public health challenge. Despite the concerns that the global disease burden may be underestimated. Therefore, evaluation of the disease epidemiology in South – eastern Asia through a systematic review will assist in unraveling the burden of the disease in the subregion. A priori protocol was prepared for the systematic review and followed by a literature search involving five electronic databases. Identified publications were screened for high quality studies and the elimination of bias and relevant data extracted. A total of 4157 citations were captured, and only 35 were included in the review. A wide range of HEV seroprevalence was recorded from 2% (urban blood donors in Malaysia) to 77.7% (lowland communities in Lao PDR). Sporadic HEV infection and epidemics were also detected in the subregion. Indicating hyperendemicity of the disease in South – eastern Asia.

HEV-LFS : A novel scoring model for patients with hepatitis E virus-related liver failure

A noninvasive assessment method for acute or acute-on-chronic liver failure in patients with hepatitis E virus (HEV) infection is urgently needed. We aimed to develop a scoring model for diagnosing HEV patients who developed liver failure (HEV-LF) at different stages. A cross-sectional set of 350 HEV-LF patients were identified and enrolled, and the Guidelines for Diagnosis and Treatment of Liver Failure in China and the Asian Pacific Association for the Study of the Liver were adopted as references. HEV-LF_S , a novel scoring model that incorporates data on cholinesterase (CHE), urea nitrogen (UREA), platelets and international normalized ratio was developed using a derived dataset. For diagnosing HEV-LF stages F1 to F3, the HEV-LF_S scoring model (F1: 0.87; F2: 0.90; F3: 0.92) had a significantly higher AUROC than did the CLIF-C-ACLFs (F1: 0.65; F2: 0.56; F3: 0.51) and iMELD (F1: 0.70; F2: 0.57; F3: 0.51) scoring models, of which the HEV-LF_S scoring model had the best sensitivity and specificity. In addition, the HEV-LF_S scoring model was correlated with mortality, length of hospitalization and ICU stay. As the GDTLF score increased, the CHE level decreased and the UREA increased gradually. Encouragingly, a calibration curve showed good agreement between the derivation and validation sets. Notably, we also established a nomogram to facilitate the practical operability of the HEV-LF_S scoring model in clinical settings. In conclusion, both CHE and UREA may be indicators for HEV-LF patients. The HEV-LF_S scoring model is an efficient and accessible model for classifying HEV-LF at different stages.

A Nationwide Survey of the Seroprevalence of Hepatitis E Virus Infections Among Blood Donors in Thailand

Hepatitis E virus (HEV) is a common cause of acute hepatitis infections. Our previous 3-year study at two large Thai hospitals established an occurrence of 4-5% of HEV infections from swine HEV genotype 3 in suspected acute hepatitis patients, with the high incidence in older adults. This study was a serosurvey to determine the prevalence of HEV infections among Thai adults. We obtained sera from 630 healthy blood donors with a median age of 38 (18-64) years who attended Thai Red Cross transfusion units throughout Thailand. The donors were domiciled in 16 provinces in the northern (n = 159), central (n = 193), northeastern (n = 158), and southern (n = 120) regions. The seroprevalence of IgG antibody to HEV (anti-HEV) was determined by the EUROIMMUN test kit, using indirect enzyme-linked immunosorbent assay (ELISA) based on recombinant antigens derived from ORF2 of HEV genotypes 1 and 3. Demographic data, including information related to HEV infection risk (the number of pigs and the proportion of Muslims in each province), were also obtained. The overall anti-HEV prevalence among Thai adults was 29.7%. The frequencies of anti-HEV found in the northern (28.9%, 95% confidence interval [CI] = 22.4-36.4), northeastern (34.8%, 95% CI = 27.8-42.5), and central (35.8%, 95% CI = 29.3-42.7) regions were similar, whereas the frequency in the southern (14.2%, 95% CI = 9.0-21.5) region, known to have a large Muslim population, was low. An increasing frequency of the specific antibody was observed among the elderly. A low HEV infection rate was associated with an Islamic population where there are low number of pigs and low swine consumption. Furthermore, the higher anti-HEV incidences in the northeastern provinces might relate to the local cultural practice of consuming undercooked pork. Besides the need for an HEV vaccination in the future, there is a requirement for rapid early diagnosis; the undertaking of prevention-management campaigns might also reduce the number of infected patients.

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

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

Hepatitis E Virus in Pork and Variety Meats Sold in Fresh Markets

Swine is an economically important livestock, yet pork consumption and close contact with pigs are associated with the risk of hepatitis E virus (HEV) infection. Limited data on the prevalence of HEV in Southeast Asia have mainly examined farm animals. To investigate the potential zoonotic transmission of HEV from dietary consumption of pork and variety meats (i.e., offal or organ meats), we obtained 1090 liver, 559 pork meat, and 556 intestine samples from fresh markets in the Bangkok metropolitan area between November 2014 and February 2015. The presence of HEV was assessed using reverse-transcription polymerase chain reaction. Concurrently, 720 bile and 553 fecal samples from a slaughterhouse were also examined. Overall, HEV RNA was found in 0.23 % of the market samples and 3.93 % of the slaughterhouse samples. Fecal and bile samples were more likely to test positive compared to liver, pork, and intestine samples (p < 0.001). Phylogenetic analysis showed that all HEV sequences obtained in this study formed a cluster closely related to genotype 3f. Pork and variety meats derived from pigs are commonly sold in fresh markets throughout Southeast Asia. Here, a relatively low HEV prevalence from pork and variety meats sold in Bangkok was found. Additional studies will be required to further assess potential dietary transmission of HEV elsewhere in the region.