Hepatitis E seroprevalence and associated risk factors in Croatian liver transplant recipients

The Risk of Reinfection or Primary Hepatitis E Virus Infection at a Liver Transplant Center in Brazil: An Observational Cohort Study

The hepatitis E virus is a major etiological agent of chronic hepatitis in immunosuppressed individuals. Seroprevalence in the liver transplantation setting varies according to the seroprevalence of the general population in different countries. This was a prospective cohort study of liver transplant recipients in southeastern Brazil. Recipients were systematically followed for one year, with the objective of determining the prevalence, incidence, and natural history of HEV infection in this population. We included 107 liver transplant recipients and 83 deceased donors. Positivity for anti-HEV IgG was detected in 10.2% of the recipients and in 9.7% of the donors. None of the patients tested positive for HEV RNA at baseline or during follow-up. There were no episodes of reactivation or seroconversion, even in cases of serological donor-recipient mismatch or in recipients with acute hepatitis. Acute and chronic HEV infections seem to be rare events in the region studied. That could be attributable to social, economic, and environmental factors. Our data indicate that, among liver transplant recipients, hepatitis E should be investigated only when there are elevated levels of transaminases with no defined cause, as part of the differential diagnosis of seronegative hepatitis after transplantation.

Seroprevalence Trends and Molecular Epidemiology of Viral Hepatitis in Croatia

Viral hepatitis is a significant cause of morbidity and mortality worldwide. In Croatia, hepatitis B virus (HBV) and hepatitis C virus (HCV) are widely distributed, especially in some high-risk groups such as people who inject drugs (PWID), prisoners, and highly promiscuous groups. The seroprevalence of HBV ranges from 7.0% in the general population to 38.8% in PWID, depending on the region. The seroprevalence of HCV is highest among PWID (29-75.5%) as compared to 0.9% in the general population. Analyzing the distribution of HCV genotypes, no substantial changes in the molecular epidemiology of the two most frequent HCV genotypes (1 and 3) in the past 20 years were observed. However, the predominance of subtype 1b compared to subtype 1a as detected in 1996-2005 was not confirmed in 2008-2015. Hepatitis A virus (HAV) incidence was high in the past with a decreasing trend since the 2000s, except for an outbreak in 2017-2018 as part of the large European outbreak, which was mainly among men who have sex with men. Hepatitis E virus (HEV) is an emerging virus detected for the first time in Croatia in 2012. The seroprevalence of HEV is high among hemodialysis patients (27.9%) and liver transplant recipients (19.3-24.4%). In addition, higher seroprevalence rates were observed in animal-related professions (e.g., veterinarians, 15.2%; hunters, 14.9%). All detected HEV strains belonged to genotype 3.

Hepatitis E Virus Infection, a Risk for Liver Transplant Recipients in Sweden

Following exposure to hepatitis E virus (HEV), liver transplant (LT) recipients have an increased risk of developing chronic infection, which may rapidly progress to severe liver damage if not treated. The prevalence of HEV infection after LT is unclear and likely varies geographically. The aim of this study was to investigate the prevalence of acute and chronic HEV infection among LT recipients in an HEV endemic region.

Insights into hepatitis E virus epidemiology in Croatia

BACKGROUND

Hepatitis E virus (HEV) is an emerging virus of global health concern. The seroprevalence rates differ greatly according to geographic region and population group.

AIM

To analyze the seroprevalence of HEV in exposed (animal-related professions) and nonexposed populations, as well as solid organ and hematopoietic stem cell transplant patients.

METHODS

Forestry workers (n = 93), hunters (n = 74), and veterinarians (n = 151) represented the exposed population. The general population (n = 126) and pregnant women (n = 118) constituted the control group. Transplant patients included liver transplant recipients (LTRs) (n = 83), kidney transplant recipients (KTRs) (n = 43), and hematopoietic stem cell transplant recipients (HSCRs) (n = 39). HEV immunoglobulin G antibodies were detected using the enzyme-linked immunosorbent assay and confirmed by the immunoblot test.

RESULTS

The HEV seroprevalence significantly differed between groups: Veterinarians 15.2%, hunters 14.9%, forestry workers 6.5%, general population 7.1%, and pregnant women 1.7%. In transplant patients, the seropositivity was highest in LTRs (19.3%), while in KTRs and HSCRs, the seroprevalence was similar to the general population (6.9% and 5.1%, respectively). A significant increase in seropositivity with age was observed from 2.9% in individuals less than 30 years to 23.5% in those older than 60 years. Sociodemographic characteristics (sex, educational level, area of residence, and number of household members), eating habits (game meat, offal, and pork products consumption), and environmental and housing conditions (drinking water supply, type of water drainage/sewer, waste disposal, domestic animals) were not associated with HEV seropositivity. However, individuals who reported a pet ownership were more often seropositive compared to those who did not have pet animals (12.5% vs 7.0%).

CONCLUSION

The results of this study showed that individuals in professional contact with animals and LTRs are at higher risk for HEV infection. In addition, age is a significant risk factor for HEV seropositivity.

Epidemiology and treatment of hepatitis E in the liver transplantation setting: A literature review

Hepatitis E virus (HEV) is a common cause of acute hepatitis in developing countries, but it can also take a chronic course especially in immunocompromised patients. Its epidemiology after liver transplantation (LT) is hard to assess and treatment options are still explored. Between 2009 and 2020, literature reporting HEV prevalence and treatment in LT recipients was searched and a synthesis was attempted. Sixteen studies reported HEV prevalence in consecutive LT patients: HEV RNA positivity ranged between 0%-1.4% and 0%-7.7% for Western and Eastern cohorts, respectively. In studies published between 2009-2014 and 2015-2020, HEV RNA positivity ranged between 0.35%-1.3% (all European) and 0%-7.7% (European: 0%-1.4%), respectively. Five studies evaluated HEV prevalence in LT recipients with abnormal liver enzymes: HEV RNA positivity was 2.9% in studies published between 2009 and 2014 and from 3.5% to 20% in studies published between 2015 and 2020. Twenty-seven studies reported HEV treatment in LT recipients: sustained virologic response was achieved in 15% by immunosuppression reduction alone and in 83% of cases by ribavirin regiments. Chronic HEV infection is affecting LT recipients, mostly those with abnormal liver enzymes and in Eastern countries. HEV diagnoses should be based on PCR techniques. Successful treatment can be achieved with ribavirin in most cases.

Hepatitis E Virus in Croatia in the "One-Health" Context

Hepatitis E virus (HEV) is the most common cause of viral hepatitis globally. The first human case of autochthonous HEV infection in Croatia was reported in 2012, with the undefined zoonotic transmission of HEV genotype 3. This narrative review comprehensively addresses the current knowledge on the HEV epidemiology in humans and animals in Croatia. Published studies showed the presence of HEV antibodies in different population groups, such as chronic patients, healthcare professionals, voluntary blood donors and professionally exposed and pregnant women. The highest seroprevalence in humans was found in patients on hemodialysis in a study conducted in 2018 (27.9%). Apart from humans, different studies have confirmed the infection in pigs, wild boars and a mouse, indicating the interspecies transmission of HEV due to direct or indirect contact or as a foodborne infection. Continued periodical surveys in humans and animals are needed to identify the possible changes in the epidemiology of HEV infections.

Emerging and Neglected Viruses of Zoonotic Importance in Croatia

Several arboviruses have emerged in Croatia in recent years. Tick-borne encephalitis is endemic in continental counties; however, new natural micro-foci have been detected. Two autochthonous dengue cases were reported in 2010. West Nile virus emerged in 2012, followed by emergence of Usutu virus in 2013. Although high seroprevalence rates of Toscana virus have been detected among residents of Croatian littoral, the virus remains neglected, with only a few clinical cases of neuroinvasive infections reported. Lymphocytic choriomeningitis virus is a neglected neuroinvasive rodent-borne virus. So far, there are no reports on human clinical cases; however, the seroprevalence studies indicate the virus presence in the Croatian mainland. Puumala and Dobrava hantaviruses are widely distributing rodent-borne viruses with sporadic and epidemic occurrence. Hepatitis E virus is an emerging food-borne virus in Croatia. After the emergence in 2012, cases were regularly recorded. Seropositivity varies greatly by region and population group. Rotaviruses represent a significant healthcare burden since rotavirus vaccination is not included in the Croatian national immunization program. Additionally, rotaviruses are widely distributed in the Croatian ecosystem. A novel coronavirus, SARS-CoV-2, emerged in February 2020 and spread rapidly throughout the country. This review focuses on emerging and neglected viruses of zoonotic importance detected in Croatia.

The Burden of Hepatitis E Infection in Chronic Liver Diseases in Croatia

In patients with chronic liver disease (CLD), hepatitis E virus (HEV) may lead to decompensation and death. We tested 438 CLD patients (71.0% male; age 23-84 years) for HEV-IgG antibodies. Reactive samples were tested for HEV-IgM antibodies using ELISA. IgM positive samples were tested for HEV RNA using RT-PCR. HEV-IgG antibodies were found in 15.1% of patients, whereas 4.5% of IgG positive patients had detectable IgM antibodies. Not a single patient tested HEV RNA positive. Seroprevalence increased with age, from 9.7% (<45 years) to 17.4% (>60 years, p = 0.368). There was no difference in HEV-IgG seropositivity related to gender, level of education, geographic region, area of residence, liver disease, or hepatocellular carcinoma presence. Previous exposure to HEV was detected in 15.1% of patients, corresponding with the data from other endemic European regions. Despite the high local exposure, we did not find any evidence of acute or chronic hepatitis E among CLD patients.

Seroepidemiology of hepatitis E in patients on haemodialysis in Croatia

PURPOSE

Data on the seroprevalence of hepatitis E virus (HEV) in heamodialysis (HD) patients are conflicting, ranging from 0 to 44%. The aim of this study was to determine the HEV seroprevalence and risk factors among HD patients in Croatia.

METHODS

A total of 394 HD patients from six medical facilities in five Croatian cities (three sites in the continental and three sites in the coastal region) were tested for HEV IgM/IgG antibodies using an enzyme-linked immunosorbent assay. Additionally, all samples were tested for HEV RNA by RT-PCR. Sociodemographic data and risk factors were collected using a questionnaire.

RESULTS

HEV IgG antibodies were detected in 110 (27.9%) patients. The seroprevalence varied significantly between dialysis centres, ranging from 5.2 to 43.4% (p = 0.001). HEV IgM antibodies were found in 0.04% of IgG positive patients. All patients tested negative for HEV RNA. Factors associated with HEV IgG seropositivity were age > 60 years (OR 8.17; 95% CI 1.08-62.14), living in the continental parts of the country (OR 2.58; 95% CI 1.55-4.30), and transfusion of blood products (OR 1.66; 95% CI 1.01-2.73). After adjusting for age and gender, patients from continental regions had higher odds of HEV seropositivity compared to patients from coastal regions (OR 2.88; 95% CI 1.71-4.85) and those who had RBC transfusions (OR 1.70, 95% CI 1.02-2.69) compared to those who did not.

CONCLUSION

The study showed a high HEV seropositivity among HD patients in Croatia, with significant variations between geographical regions. Continental area of residence and RBC transfusion were the most significant risk factors for HEV seropositivity. Due to the high seroprevalence, routine HEV screening among HD patients, especially in transplant candidates should be considered.