Prevalence of antibody to hepatitis E virus among healthy individuals in southern Taiwan

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.

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.

Seroprevalence of hepatitis E virus infection among institutionalized psychiatric patients in Taiwan

BACKGROUND

Hepatitis E virus infection (HEV) remains unclear in institutionalized psychiatric patients.

OBJECTIVES

To investigate the prevalence and risk factors of HEV infection in a psychiatric institution in Taiwan.

STUDY DESIGN

A total of 754 patients with psychiatric disorders were enrolled in the study. Clinical features, review of patient charts, and interviews with families were recorded for analysis. Antibody to HEV was tested using a commercial enzyme-linked immunosorbent assays.

RESULTS

The prevalence of HEV infection in institutionalized patients was as high as 14.5%. Males had higher prevalence than females. It was also found prevalence increased significantly by age group. When compared with patients 30 years old or less, those in the 31-40 year old age group had an odds ratio of 4.89 [95% confidence interval (CI), 1.15-20.82], 41-50 years old of 6.30 (95% CI, 1.48-26.83), and 50 years or older of 6.20 (95% CI, 1.44-26.74). In multivariate logistic regression analysis, age and male gender were the independent risk factors.

CONCLUSIONS

Institutionalized psychiatric patients had higher prevalence of HEV infection. In addition, there was an age-related increase in exposure to HEV with males that had a higher HEV seropositivity.

Seroepidemiology of hepatitis E virus infection among preschool children in Taiwan

In order to study the seroprevalence of hepatitis E virus (HEV) infection among preschool children in Taiwan, a community-based survey was carried out in 54 kindergartens in 10 urban areas, 10 rural areas, and 2 aboriginal areas randomly selected through stratified sampling. Serum specimens of 2,538 preschool children were screened for HEV antibodies (anti-HEV) by a commercially available enzyme immunoassay. The odd ratios (OR) with 95% confidence intervals (CI) were estimated through multiple logistic regression analysis. A total of 86 children were anti-HEV seropositive, giving a prevalence of 3.4%. The prevalence of anti-HEV was 3.9% (19 of 484) among aboriginal children, a significantly increased seroprevalence compared with that among children who lived in urban areas (OR = 1.68; 95% CI = 1.56-2.95; P < 0.05). Females had a higher anti-HEV seroprevalence than the males (OR = 1.55; 95% CI = 1.14-2.54; P < 0.05). Rates of anti-HEV antibody increased with age in aboriginal areas (chi(2) for trend = 5.59, P = 0.02), but decreased with age in non-aboriginal areas. The poor water supply system, poor sewage disposal, exposure to wild animals, and other environmental conditions in the aboriginal areas might have played a role in their infection with HEV in Taiwan.

Evidence of extrahepatic sites of replication of the hepatitis E virus in a swine model

Hepatitis E virus (HEV) is the major cause of enterically transmitted non-A, non-B hepatitis in many developing countries and is also endemic in many industrialized countries. Due to the lack of an effective cell culture system and a practical animal model, the mechanisms of HEV pathogenesis and replication are poorly understood. Our recent identification of swine HEV from pigs affords us an opportunity to systematically study HEV replication and pathogenesis in a swine model. In an early study, we experimentally infected specific-pathogen-free pigs with two strains of HEV: swine HEV and the US-2 strain of human HEV. Eighteen pigs (group 1) were inoculated intravenously with swine HEV, 19 pigs (group 2) were inoculated with the US-2 strain of human HEV, and 17 pigs (group 3) were used as uninoculated controls. The clinical and pathological findings have been previously reported. In this expanded study, we aim to identify the potential extrahepatic sites of HEV replication using the swine model. Two pigs from each group were necropsied at 3, 7, 14, 20, 27, and 55 days postinoculation (DPI). Thirteen different types of tissues and organs were collected from each necropsied animal. Reverse transcriptase PCR (RT-PCR) was used to detect the presence of positive-strand HEV RNA in each tissue collected during necropsy at different DPI. A negative-strand-specific RT-PCR was standardized and used to detect the replicative, negative strand of HEV RNA from tissues that tested positive for the positive-strand RNA. As expected, positive-strand HEV RNA was detected in almost every type of tissue at some time point during the viremic period between 3 and 27 DPI. Positive-strand HEV RNA was still detectable in some tissues in the absence of serum HEV RNA from both swine HEV- and human HEV-inoculated pigs. However, replicative, negative-strand HEV RNA was detected primarily in the small intestines, lymph nodes, colons, and livers. Our results indicate that HEV replicates in tissues other than the liver. The data from this study may have important implications for HEV pathogenesis, xenotransplantation, and the development of an in vitro cell culture system for HEV.