Seroprevalence of Hepatitis E Virus Infection among Blood Donors in Bulgaria

Hepatitis E virus (HEV) infection is widespread among domestic pigs, industrial swine, and wild boars in Bulgaria. The aim of the current research was to present the HEV seroprevalence among blood donors in Bulgaria. In the present study, 555 blood donors (479 males and 76 females) were enrolled from five districts in the country (Shumen, Pleven, Stara Zagora, Plovdiv, and Sofia districts). All blood samples were tested for anti-HEV IgG using the recomWell HEV IgG ELISA test (Mikrogen GmbH, Neuried, Germany). Each participating donor completed a short, structured, and specific questionnaire to document data on the current study. Anti-HEV IgG positive results were detected in 144 (25.9%) blood donors, including 129 (26.9%) males and 15 (19.7%) females. The established HEV seropositivity was 28.8% (23/80) in Shumen district, 23.2% (22/95) in Pleven district, 27.1% (38/140) in Stara Zagora district, 27.5% (44/160) in Plovdiv district, and 21.3% (17/80) in Sofia district. A high HEV seroprevalence was found for persons who declared that they were general hunters (48.7%; 19/39; p = 0.001) and hunters of wild boars (51.6%; 16/31; p = 0.001). We present the first seroprevalence rates of HEV infection in blood donors from Bulgaria. The results of our research showed high HEV seropositivity among blood donors.

Seroepidemiology of hepatitis E virus infection in patients undergoing maintenance hemodialysis: Systematic review and meta-analysis

Patients undergoing regular hemodialysis (HD) are at an extreme risk of acquiring bloodstream infections compared to the general population. Hepatitis E virus (HEV) infection is an important emerging health issue in these patients. To date, numerous studies have investigated the seroprevalence of HEV among HD patients across the world; however, the data are conflicting. The present study aimed to measure the exposure rate of HD patients to HEV infection by estimating the overall seroprevalence of HEV in this high-risk group. A systematic literature search was carried out using five electronic databases from inception to January 10, 2020, with standard keywords. Pooled seroprevalence estimates with 95% confidence intervals (CIs) were calculated using a random intercept logistic regression model. The seroprevalence of HEV increased from 6.6% between the years of 1994 and 2000 to 11.13% from 2016 to 2020. Blood transfusion was associated with a nearly 2-fold increase in the rate of HEV seropositivity (OR = 1.99; 95% CI: 1.50-2.63, P < .0001, I² = 6.5%). HEV seroprevalence among patients with HD for more than 60 months was significantly higher than those with HD for less than 60 months (27.69%, 95% CI: 20.69%-35.99% vs 15.78%, 95%CI: 8.85%-26.57%, respectively) (P = .06). Our results indicated increased exposure of HD patients with HEV infection over the last decade. We concluded that blood transfusion and duration of HD are considerable risk factors for acquiring HEV infection among HD patients.

Systematic review and meta-analysis of the seroprevalence of hepatitis E virus in the general population across non-endemic countries

BACKGROUND

Hepatitis E virus (HEV) has commonly been associated with large waterborne outbreaks of human jaundice in endemic areas but it has been increasingly recognised as a cause of sporadic human cases of jaundice in non-endemic areas, in individuals with no history of travel. Zoonotic exposure is widely hypothesized to be an important potential transmission route in these sporadic human cases. Serosurveys conducted to determine the frequency of HEV human exposure report wide ranges in prevalence across studies and locations. Our study objective was to compute meta-analysis summary estimates of human seroprevalence of HEV IgG within countries considered HEV non-endemic, where possible, and to determine whether this varied significantly across these countries, as well as investigating the role of potential HEV seroprevalence predictors such as population age structure.

MATERIALS AND METHODS

A broad literature search was conducted in six electronic databases. Citations were appraised, and relevant data extracted using forms designed and pre-tested a priori. Meta-analysis and meta-regression were conducted in R, with HEV IgG seroprevalence in blood donors or the general population being the outcome of interest, and country, assay, population age and sex structure, and chronological time investigated as predictors of the outcome.

RESULTS

From 4163 unique citations initially captured, data were extracted from 135 studies investigating HEV serology in blood donors or the general population, of 31 countries among those categorised as 'very high human development' by the United Nations. Country of sampling and assay employed were consistently significant predictors of HEV IgG seroprevalence with chronological time being a non-significant predictor in the dataset of captured studies.

CONCLUSIONS

While country of sampling and assay employed were significant predictors of HEV seroprevalence, comparison of HEV seroprevalence across non-endemic countries is hampered by the lack of a gold standard assay and uncertainty regarding residual bias across studies, as well as regional differences within some countries.

Meta-Analysis of Human IgG anti-HEV Seroprevalence in Industrialized Countries and a Review of Literature

Although Hepatitis E is increasingly described as a major cause of liver disease in industrialized countries, the epidemiology is far from being fully elucidated. We provide here a comprehensive review of documented clusters of cases, and of serological studies conducted in populations with distinct types of exposure. Seroprevalence rates range from <5% to >50% depending on the countries and the groups of population. Such discrepancies can be attributed to the type of serological assay used, but this solves only a part of the problem. We performed a meta-analysis of studies performed with the broadly used Wantai HEV-IgG ELISA and found striking differences that remain difficult to understand with the current knowledge of transmission pathways.

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.

Detection of Hepatitis E Virus Genotype 1 Among Blood Donors From Southwest of Iran

BACKGROUND

Infection with hepatitis E virus (HEV) is endemic in developing countries and reveals significant regional differences. Several studies have reported virus transmission via blood transfusion. To date, however, no cases of HEV RNA detection in blood donors have been reported from Iran.

OBJECTIVES

The aim of this study was to determine the presence of HEV RNA in plasma samples of blood donors referred to a blood transfusion center in Shiraz in the southwest of Iran. The HEV genotypes were also investigated using nucleotide sequencing.

PATIENTS AND METHODS

Blood samples were collected from 700 blood donors who were referred to Fars blood transfusion organization from January to March 2014. Plasma samples were screened for the presence of HEV IgG and IgM antibodies by standard enzyme immunoassay. Samples seroreactive to anti-HEV were further tested for the presence of HEV RNA using nested polymerase chain reaction (PCR) with universal primers for detection of all four HEV genotypes. Positive PCR samples were then subjected to DNA sequencing for further analysis.

RESULTS

Fifty (50, 7.1%) out of 700 plasma samples tested positive for anti-HEV antibodies. HEV RNA was detected in 7/50 (12%) of the antibody-positive samples, the majority of which were IgM positive. Sequence analysis of seven isolates of the HEV RNA ORF 2 gene region revealed > 80% similarity with genotype 1.

CONCLUSIONS

The analysis indicates that the HEV isolated from blood donors in the southwest of Iran belongs to genotype 1. However, more samples from other geographic regions of Iran are needed to confirm these findings. Because transmission of HEV by administration of blood or blood components is likely to occur, it may be sensible to screen donor blood for HEV to eliminate transfusion-transmitted HEV infection when the recipient is immunocompromised.

Light and Darkness: Prevalence of Hepatitis E Virus Infection among the General Population

Human hepatitis E virus (HHEV) spreads early in life among the population in areas endemic for genotype 1 and infects mainly adults in areas endemic for genotype 3, where it would be responsible for about 10% of cases of suspected acute viral hepatitis of unknown etiology and for a number of subclinical, unrecognized infections. The overall prevalence of antibody to HHEV is high in most of the former areas and low in most of the later ones, but wide regional differences have been recorded in both cases. "Hot spots" of HHEV infection would exist for both types of strains in particular regions or among particular populations of the world. Studies on pork derivatives, shellfish bivalves, and vegetables for HHEV contamination at the sale point need to be extended for evaluating the impact of the agent on food safety, and the meaning of the finding of HHEV genotype 1 genomes in urban sewage from developed countries should be established through active surveillance. Consensus about technical issues in regard to anti-HEV testing would improve the knowledge of the HHEV epidemiology. Studies in particular regions and populations, and introduction of molecular diagnosis in the clinical setting as a routine tool, would also be required.

Cirrhosis, liver transplantation and HIV infection are risk factors associated with hepatitis E virus infection

BACKGROUND

Acute and chronic hepatitis E have been associated with high mortality and development of cirrhosis, particularly in solid-organ recipients and patients infected by human immunodeficiency virus. However, data regarding the epidemiology of hepatitis E in special populations is still limited.

AIMS

Investigate seroprevalence and possible factors associated with HEV infection in a large cohort of immunosuppressed patients.

METHODS

Cross-sectional study testing IgG anti-HEV in serum samples from 1373 consecutive individuals: 332 liver-transplant, 296 kidney-transplant, 6 dual organ recipients, 301 non-transplanted patients with chronic liver disease, 238 HIV-infected patients and 200 healthy controls.

RESULTS

IgG anti-HEV was detected in 3.5% controls, 3.7% kidney recipients, 7.4% liver transplant without cirrhosis and 32.1% patients who developed post-transplant cirrhosis (p<0.01). In patients with chronic liver disease, IgG anti-HEV was also statistically higher in those with liver cirrhosis (2% vs 17.5%, p<0.01). HIV-infected patients showed an IgG anti-HEV rate of 9.2%, higher than those patients without HIV infection (p<0.03). Multivariate analysis showed that the factors independently associated with anti-HEV detection were liver cirrhosis, liver transplantation and HIV infection (OR: 7.6, 3.1 and 2.4). HCV infection was a protective factor for HEV infection (OR: 0.4).

CONCLUSIONS

HEV seroprevalence was high in liver transplant recipients, particularly those with liver cirrhosis. The difference in anti-HEV prevalence between Liver and Kidney transplanted cases suggests an association with advanced liver disease. Further research is needed to ascertain whether cirrhosis is a predisposing factor for HEV infection or whether HEV infection may play a role in the pathogeneses of cirrhosis.

Patients infected with HIV are at high-risk for hepatitis E virus infection in Spain

Hepatitis E virus is responsible for sporadic cases of acute, self-limited viral hepatitis not only in endemic but also in industrialized countries. In addition, some reports confirm that it can cause chronic infection and even cirrhosis in immunosuppressed and also in patients infected with HIV. There are few data about prevalence and incidence of HEV chronic infection in HIV-HEV coinfected individuals in Spain. The aim of this study is to investigate the prevalence of anti-HEV IgG in a representative sample of 448 patients infected with HIV and determine the role of age, gender, and CD4 counts in the detection of anti-HEV IgG antibodies in blood. In addition, the clinical features and ALT levels in relation to the presence of anti-HEV IgM and/or HEV-RNA in the blood of these patients were investigated. Anti-HEV IgG antibodies were detected in serum using a commercial enzyme immunoassay. All positive samples were studied further for the presence of anti-HEV IgM antibodies. In addition, HEV RNA was amplified by reverse transcriptase (RT)-nested PCR in all serum samples with IgM anti-HEV. The overall prevalence of anti-HEV IgG was 10.4% (45/448, 95% C.I. 7.2-12.8%). HEV-RNA was found in only one patient out of the 45 anti-HEV IgG positive samples studied. Regarding to gender and CD4 count, no difference in seroprevalence could be observed. This prevalence data suggest that patients infected with HIV can be considered a risk group for HEV infection and that chronic coinfection HEV-HIV seems to be a very rare event.

[Acute, chronic and fulminant hepatitisE: seven years of experience (2004-2011)]

OBJECTIVE

To study the clinical and epidemiological profiles of in 43cases of acute hepatitis, 5cases of fulminant hepatitis, and one of chronic hepatitis due to hepatitis E virus (HEV), detected over a 7-year period.

PATIENTS

Forty-nine individuals (33male and 10female) treated between 2004 and 2011 in the Hospital Ramón y Cajal (Comunidad de Madrid, Spain). The diagnosis was made by the detection of IgG and IgM anti-HEV and RNA HEV in serum samples. Acute hepatitisE was defined by the presence of IgM anti-HEV and/or RNA HEV in serum, and chronic hepatitisE if the ARN was detectable more than 6months. Fulminant hepatitisE was diagnosed if encephalopathy was observed in addition to IgM anti-HEV and/or RNA HEV in serum.

RESULTS

The median age was 46.67 and 49.6years in acute hepatitisE and fulminant hepatitisE, respectively. The risk factors recorded were travel to endemic areas in 13patients, 4were in contact with animals, 4suffered from hepatic steatosis due to alcohol consumption, 3consumed uncontrolled foods, and 2drank water from streams.

DISCUSSION

HEV is the cause of acute self-limited hepatitis, although 36.73% of the studied cases had to be hospitalised. However a small number of patients, 10.2%, had fulminant hepatitis requiring liver transplant. Chronic hepatitisE is very infrequent in immunocompetent individuals. The increase in incidence of hepatitisE is due to the introduction of better diagnostic tests in recent years.

[Hepatitis E: scale of the problem in Spain]

Hepatitis E virus (HEV) infection is one of the most frequent causes of acute hepatitis worldwide. However, in Spain, HEV causes only a tiny number of cases of acute hepatitis, the most prevalent cause being hepatitis A. Most cases of HEV in Spain are "imported", being acquired through travel to areas where this infection is endemic. Nevertheless, in the last few years a growing number of "autochthonous cases" have been reported in persons with no history of travelling to HEV-endemic areas. The prevalence of IgG antibodies against HEV, indicating exposure to this virus, is approximately 0.6-7.3% in the general population in Spain and is 19% in persons with risk factors such as exposure to pigs.

[Hepatitis E. Current perspectives]

Infection with hepatitis E virus (HEV) is highly prevalent in developing countries and the WHO estimates one third of the world population has had contact with the virus. Its diagnosis and epidemiology are well known in endemic countries but, recently, there have been sporadic cases in developed countries in patients with no history of travel. Currently in these countries, hepatitis E is considered a zoonosis yet there remain to be known other routes of transmission. Another interesting aspect is that HEV can cause chronic hepatitis in transplanted patients, other immunocompromised patients and even in immunocompetent people. There have also been reported cases of fulminant hepatitis and other extrahepatic manifestations. The diagnosis is based on serological studies and detection of viral RNA in blood and feces. The vaccine is a good option to prevent this infection that affects a large number of people in deprived geographical areas but unfortunately it is not available yet.

Transmission routes and risk factors for autochthonous hepatitis E virus infection in Europe: a systematic review

Increasing numbers of non-travel-associated hepatitis E virus (HEV) infections have been reported in Europe in recent years. Our objective was to review the evidence on risk factors and transmission routes of autochthonous HEV infection and hepatitis E in Europe in order to develop recommendations for future research, prevention and control. A systematic literature review was performed to identify all primary reports and studies published during 1998-2008 on hepatitis E in humans and animals in Europe by searching Pubmed, reference lists of major articles and international conference proceedings. Each of the 106 included studies was categorized into one of three evidence levels (EL) based on study design and diagnostic methodology. The evidence was generally weak (73 were assigned to EL1, two to both EL1 and EL2, and 30 to EL2), further compounded by the use of poorly validated serological assays in some studies. Only one case-control study was assigned to EL3. Persons with autochthonous hepatitis E infection were on average older than the general population and predominantly male. There was no evidence for one main transmission route of HEV infection or risk factor for hepatitis E. However, zoonotic transmission seemed likely and person-to-person transmission too inefficient to cause clinical disease. Multiple routes of transmission probably exist and should be further investigated through analytical studies and reliable diagnostic kits. Based on current evidence that points to zoonotic transmission from pigs, thorough cooking of all porcine products, prevention of cross-contamination in the kitchen and improved education for occupationally exposed people (e.g. pig farmers, veterinarians and sewage workers) may help prevent HEV infection. Although evidence for parenteral transmission is limited, it is recommended that a risk assessment is undertaken.

[Hepatitis E virus: zoonotic implications]

The Hepatitis E virus (HEV) is transmitted primarily by the feco-oral route throughout contaminated water and/or food, and is one of the main causes of acute hepatitis worldwide. Hepatitis E shows a high mobility but a low mortality rate, except in pregnant women, where it can be as high as 30%. HEV causes sporadic cases and epidemic outbreaks, mainly in Africa, Asia and Central America. In Europe, there is an increase in the number of reported autochthonous cases no related with travel to endemic areas. In addition, HEV also infects animals, including pigs, and its zoonotic potential has been recently demonstrated. In fact, porcine and human strains of the same area are genetically more closely related to each other than to strains of the same species but a different geographical region, and there are data suggesting that people in close contact with pigs presents a higher prevalence of specific anti-HEV antibodies. All together, these data have drove to an increase interest in determining the incidence of the disease in animals, its possible zoonotic risk, and its implications for human health. In the present article we revised the current knowledge about HEV, with special emphasis in the possible consequences of its zoonotic potential.

Prevalence of hepatitis E virus antibodies in patients with chronic hepatitis B and chronic hepatitis C

OBJECTIVES

To investigate the prevalence of hepatitis E virus (HEV) among patients with chronic hepatitis B and chronic hepatitis C, serum samples were collected between January and December 2004 from patients with chronic hepatitis B and chronic hepatitis C.

METHODS

There were 190 adult patients with chronic hepatitis B virus (HBV) and 174 with chronic hepatitis C virus (HCV) infection in the study group. As the control group, a cohort of 178 age- and sex-matched individuals without known liver disease was selected.

RESULTS

Anti-HEV IgG antibodies were positive in 26/190 (13.7%) of chronic HBV and 94/174 (54%) of chronic HCV patients. In the control group anti-HEV positivity was 15.7% (28/178). There was no difference in the percentage of chronic HBV patients and control group who were positive for anti-HEV antibody, but the presence of HEV infection was significantly higher in chronic HCV patients.

CONCLUSIONS

Our findings suggest that HEV and HCV might share a common route of transmission in our region. We recommend that preventive measures against HEV should be undertaken in chronic HCV patients as superinfection with HEV can cause a more severe pattern of disease in chronic hepatitis patients.

Community-based seroepidemiological survey of hepatitis E virus infection in Catalonia, Spain

The objective of the study was to investigate the prevalence of immunoglobulin G (IgG) antibodies to hepatitis E virus (HEV) infection in a population sample from Catalonia and to analyze the demographic and clinical variables associated with the presence of these antibodies. A total of 1,280 subjects between 15 and 74 years of age were selected randomly from urban and rural areas. Data for sociodemographic and clinical variables were collected by using a questionnaire. IgG antibodies to HEV were determined by an immunoenzymatic method. The odds ratios (ORs) and 95% confidence intervals (95% CIs) were calculated for studied variables. Multiple logistic regression analysis was used to determine which variables were independently associated with the prevalence of HEV infection. Anti-HEV antibodies were detected in 96 (7.3%) of the 1,280 samples analyzed. The prevalence of antibodies was greater among males (7.8%) than among women (7%) and increased with age for both sexes, from 3% among subjects 15 to 24 years of age to 12% among subjects >/=65 years of age. Bivariate analysis of the sociodemographic and clinical variables showed an association between the prevalence of hepatitis E virus infection and minor surgery (OR, 1.96; 95% CI, 1.24 to 3.11), abdominal surgery (OR, 1.74; 95% CI, 1.12 to 2.73), and, for women, being uniparous or multiparous (OR, 2.84; 95% CI, 1.19 to 6.79). The multivariate analysis showed an association with minor surgery only (OR, 1.68; 95% CI, 1.03 to 2.70). In conclusion, anti-HEV antibodies were detected in 7.3% of the Catalan population. The seroprevalence of anti-HEV antibodies increased with age and was associated with previous minor surgery.

[Acute hepatitis E in Madrid: description of 18 cases]

INTRODUCTION

Hepatitis E virus (HEV) is the main cause of non-A non-B enterically transmitted hepatitis in underdeveloped countries but is rare in industrialized areas. However, in the last few years, several sporadic autochthonous hepatitis E cases have been reported in Europe and no risk factors, such as visiting to endemic areas, could be found in these patients.

OBJECTIVE AND PATIENTS

Twelve patients with sporadic autochthonous hepatitis E (no risk factors such as traveling to endemic areas) and six imported cases (travel to Nepal, Santo Domingo, China, Brazil and Ecuador) were studied between June 1999 and December 2005.

RESULTS

HEV infection was diagnosed in patients with symptoms of acute hepatitis and the presence of IgG and IgM antibodies in serum with no other markers of hepatitis. HEV infection is probably overlooked in industrialized countries.

CONCLUSIONS

This diagnosis should be suspected in patients with acute hepatitis and anti-HEV antibodies in serum without known risk factors such as traveling to endemic areas.

Markers of hepatitis viruses and human T-lymphotropic virus types I/II in patients who have undergone open-heart surgery: evidence of increased risk for exposure to HBV and HEV

BACKGROUND

Open-heart procedure is characterized by a high-risk for contracting blood-borne infections. We evaluated the prevalence of several markers of hepatitis viruses (B-E) and human T-cell lymphotropic virus types I/II (HTLV-I/II) in a consecutive series of patients who had undergone open-heart surgery.

METHODS

204 patients and 158 selected age- and sex-matched healthy volunteers were investigated. Samples were collected at least 6-12 months postoperatively. Commercial enzyme immunoassays and confirmatory immunoblot assays for HCV, HEV and HTLV-I/II were used.

RESULTS

None of the subjects tested positive for antibodies to HTLV-I/II. Prevalence of markers of past HBV infection and antibodies to HEV (anti-HEV) were higher in patients than in healthy controls (anti-HBc: 45.1% vs. 31%, p=0.009; anti-HBs: 31.9% vs. 22.2%, p=0.02; anti-HBe: 32.4% vs. 10.1%, p=0.000; anti-HEV: 5.4% vs. 0%, p=0.008). HBsAg and antibodies to HCV did not differ between the groups.

CONCLUSIONS

HTLV, HBsAg and HCV infection markers did not differ between patients and healthy controls. However, patients had significantly increased prevalence of markers of previous HBV infection suggesting that an intensive vaccination schedule against HBV preoperatively might be helpful in minimizing the risk. The increased prevalence of anti-HEV in cardiac patients requires further investigation. Prospective studies are needed in order to definitely address whether the high prevalence of exposure to HBV and HEV infections in patients who had undergone open-heart surgery is procedure-related or not and whether it has any impact on morbidity of these patients.

Emerging infections in transfusion medicine

The risk of transfusion-transmitted infectious diseases (TTIDs) has declined dramatically in high-income nations over the past 2 decades, primarily because of extraordinary success in preventing HIV and other established transfusion-transmitted viruses from entering the blood supply. Despite this achievement, TTIDs remain a public health concern, and attention is refocusing on new and emerging pathogens, such as West Nile virus, infectious proteins (the presumed cause of variant Creutzfeldt-Jakob disease), and other transmissible organisms such as bacteria and parasites. In this article the authors concentrate on this heterogeneous group of infectious agents, describe individual pathogens and the risks they pose to transfusion recipients, and comment on existing and evolving procedures that are designed to protect the blood supply from this threat.

Sporadic cases of acute autochthonous hepatitis E in Spain

BACKGROUND/AIMS

In industrialized countries hepatitis E virus (HEV) infection is rare and its diagnosis is difficult because the utility of available tests is not well established.

METHODS

We studied the presence of acute HEV infection markers in a cluster of 11 cases of acute hepatitis with IgG anti-HEV antibodies.

RESULTS

Three cases were confirmed as acute hepatitis E and 8 as presumptive hepatitis E, two as a past HEV infection and one could not be determined. Three different HEV strains were identified in serum from 3 patients. Two strains belonged to genotype 3, the predominant genotype found in local urban sewage and the other strain belonged to genotype 1 and was considered an imported strain.

CONCLUSIONS

Our findings demonstrate the presence of some autochthonous, sporadic acute hepatitis E cases as well as an imported case in our area and the transitory nature of virological and serological markers for HEV.

Hepatitis E virus epidemiology in industrialized countries

To determine the prevalence of Hepatitis E virus (HEV) in industrialized nations, we analyzed the excretion of HEV strains by the populations of Spain, France, Greece, Sweden, and the United States. Twenty of 46 (43.5%) urban sewage samples collected in Barcelona from 1994 to 2002 tested positive for HEV. We identified 15 HEV strains, which were similar to two HEV isolates previously described in Barcelona in clinical samples and to strains from diverse geographic HEV-nonendemic areas. We also identified two HEV strains in sewage samples from Washington, D.C., and Nancy, France; these samples were also positive for Hepatitis A virus. In addition, we studied the role of pigs as a reservoir for HEV and identified one new swine HEV strain. Our results suggest that HEV may be more prevalent than previously considered in industrialized countries and that variants of the virus circulate simultaneously in one region.

HEV identified in serum from humans with acute hepatitis and in sewage of animal origin in Spain

BACKGROUND/AIMS

Hepatitis E virus (HEV) is an enterically transmitted pathogen that appears sporadically in non-endemic countries. We studied HEV as a causal agent of acute hepatitis cases in the Spanish population, and the role of pigs as an animal reservoir.

METHODS

The presence of HEV-RNA was analysed by nested polymerase chain reaction in 37 serum samples from patients with acute viral hepatitis, 48 porcine serum samples, 6 pig faecal samples and 12 slaughter-house sewage samples. Presence of antibodies was also tested in porcine sera.

RESULTS

HEV-RNA was found in 3 human serum samples from patients presenting IgG anti-HEV antibodies. Nucleotide sequence analysis identified 2 strains with 93.4% identity, phylogenetically most closely related to the Greece1 isolate, and more closely related to North American and other European strains than to those from endemic regions. HEV-RNA was also detected in slaughterhouse sewage mainly from pigs, presenting 92-94% nucleotide similarity compared to the strains detected in the human sera. Twenty-five per cent of the pigs tested presented IgG anti-HEV antibodies.

CONCLUSIONS

These data suggest that the HEV could be more widespread than previously thought, and present new evidence of the close relationship between HEV strains detected in pigs and those from acute hepatitis patients.

Rapid detection of Hepatitis E virus RNA by reverse transcription-polymerase chain reaction using universal oligonucleotide primers

A rapid reverse transcription-polymerase chain reaction (RT-PCR) procedure for the detection of Hepatitis E virus (HEV) RNA in serum is described. Total nucleic acids are extracted from a small volume of human serum and reverse transcribed using random hexamers. An aliquot of cDNA is then utilized in nested PCR employing degenerate HEV consensus primers. These primers are designed to sequences conserved between the Burma, Mexico, and US HEV strains, generating amplicons within each of the three open reading frames. Reactions are analyzed by agarose gel electrophoresis and samples showing an ethidium bromide stained band of the appropriate size in the first and second amplification, or in the second amplification only, are designated as positive. This protocol allows for the rapid and sensitive detection of HEV infection in human serum.