and Bruce L. InnisTo determine hepatitis E virus (HEV) infection and disease rates in the Kathmandu Valley of Nepal, serum was collected from 757 healthy Nepalese (ages 12 -48 years) during March and September 1992 and September 1993. At each visit, reports of interval illness were obtained. Sera were examined for IgG to HEV, using a commercially available kit. Seroconversion was used as a marker for HEV infection, and an episode of hepatitis E was defined as a history of jaundice with seroconversion. Seroprevalence ranged from 16% to 31% and increased with age, whereas both infection and disease rates decreased with age. Infection and disease rates were as high as 99/1000 and 45/1000 person-years, respectively. These results highlight the importance of sporadic hepatitis E as a public health problem among adolescents and young adults in this region. Hepatitis E virus (HEV) is believed to be the primary agentStudies to characterize the prevalence of IgG to HEV began as a result of the recent development of serologic assays for responsible for enterically transmitted non-A, non-B hepatitis. The most commonly reported signs and symptoms of this dis-HEV. Generally, the prevalence of antibody against HEV is low (0% -3%) in areas where no outbreaks have been reported ease include malaise, jaundice, dark urine, nausea, abdominal pain, fever, hepatomegaly, and vomiting [1]. The mortality rate and sporadic cases are rare (e.g., in the United States, Europe, Australia, Japan, New Zealand, South Africa, and Thailand) for hepatitis E is higher than for hepatitis A and ranges from 1% -3% among men and nonpregnant women to 12% -42% [5 -8]. By contrast, the prevalence of antibody against HEV is higher (10% -40%) in regions where outbreaks have been among pregnant women [2]. High rates of perinatal death are also associated with this disease [3,4]. Hepatitis E is an imreported and sporadic transmission occurs regularly, such as India, Nepal, and Tajikistan [6,7,9, 10]. Age-specific antibody portant health concern in nearly all under-developed regions of the world. No vaccines for hepatitis E have been developed, prevalence has been examined in India and Nepal [9, 10]. In both studies, antibody prevalence was found to increase with and prophylaxis with immune serum globulin appears to have little or no protective effect [2]. age until about age 30 years. No increase in antibody prevalence was apparent after age 30. No sex-dependent differences in antibody prevalence were observed; on the other hand, in older age groups, the numbers of women were too small to NOTE. Serum and medical histories were collected from 757 persons during March and September 1992 and September 1993. Case of hepatitis E was defined as episode of jaundice (self-reported during interview) along with acquisition of IgG to HEV during period examined. Infection was based on acquisition of HEV antibody during period examined. IgG to HEV was detected using ELISA developed by Diagnostic Biotechnology (Singapore). All 3 serum specimens from each individual were ...

Hepatitis E virus (HEV) genome was detected by reverse transcriptase-polymerase chain reaction (RT-PCR) in fecal samples of two sporadic cases of hepatitis E in Cairo Egypt. Sequence of the complete putative structural region [open reading frame (ORF)-2] and complete region of unknown function (ORF-3) was determined for the two HEV isolates. Phylogenetic analysis of the nucleotide sequences was performed using neighbor joining or maximum parsimony methods of tree reconstruction. Direct correspondence between the HEV evolutionary trees and geographic origin of the HEV isolates was observed. Three genotypes of HEV were identified: genotype I (Asia-Africa), genotype II (US), and genotype III (Mexico). Genotype I was further divided into two subgenotypes (Asia and Africa). In the Asian subgenotype, three smaller genetic clusters were observed (China-like sequences, Burma-like sequences, and sequence from a fulminant case of HEV). The segregation of all these genetic clusters was supported by the high level of bootstrap probabilities. Four regions of the HEV genome were used for phylogenetic analysis. In all four regions, Egyptian HEV isolates were grouped in a separate African clade.

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The purpose of this study was to analyze partial nucleotide sequences and derived peptide sequences of hepatitis E virus (HEV) from two outbreaks of hepatitis E in Africa (Chad 1983-1984; Algeria 1978-1980). A portion of ORF3 and the major portion of ORF2 were amplified by Reverse Transcriptase-Polymerase Chain Reaction (RT-PCR). The PCR products were sequenced directly or after cloning into the pCRII vector. Sequences were then compared to the corresponding regions of reported full length HEV sequences. In the ORF2 and ORF3 regions, the homology between the Algerian and the Chad isolates at the nucleic acid level was 92 and 95%, respectively. At the peptide level the homology was 98% in both regions. In these regions, both strains are more related to Asian strains at the nucleic acid level (89 to 95%) and at the amino acid level (95 to 100%) than to the Mexico strain. At the peptide level the differences are less apparent. Both African isolates have amino acid changes in common with some reference strains although the Chad isolate has three unique changes. These African strains of HEV, based on the ORF2 and ORF3 phylogenetic trees, appear to be a distinct phylogenetic group, separate from the Mexican and Asian strains.

We developed a quantitative enzyme immunoassay (EIA) for antibody to hepatitis E virus (HEV) by using truncated HEV capsid protein expressed in the baculovirus system to improve seroepidemiology, to contribute to hepatitis E diagnosis, and to enable vaccine evaluations. Five antigen lots were characterized; we used a reference antiserum to standardize antigen potency. We defined Walter Reed antibody units (WR U) with a reference antiserum by using the four-parameter logistic model, established other reference pools as assay standards, and determined the conversion factor: 1 WR U/ml ‫؍‬ 0.125 World Health Organization unit (WHO U) per ml. The EIA performed consistently; median intra-and intertest coefficients of variation were 9 and 12%, respectively. The accurate minimum detection limit with serum diluted 1:1,000 was 5.6 WR U/ml; the test could detect reliably a fourfold antibody change. In six people followed from health to onset of hepatitis E, the geometric mean antibody level rose from 7.1 WR U/ml to 1,924.6 WR U/ml. We used the presence of 56-and 180-kDa bands by Western blotting as a confirmatory test and to define true-negative and -positive serum specimens. A receiver-operating characteristics plot identified 30 WR U/ml as an optimum cut-point (sensitivity, 86%; specificity, 89%). The EIA detected antibody more sensitively than a commercially available test. The EIA was transferred to another laboratory, where four operators matched reference laboratory results for a panel of unknowns. Quantitation of antibody to HEV and confirmation of its specificity by Western blotting make HEV serology more meaningful.Hepatitis E is acute self-limited hepatitis caused by hepatitis E virus (HEV), which is excreted in feces and transmitted orally. In large parts of Asia and Africa, this disease is common, causing sporadic and epidemic illness (12). HEV serology to diagnose disease and identify individuals previously infected has improved steadily (2-6, 8, 9, 11, 18, 19). Nevertheless, the art remains imperfect (13).Among the best tests for antibody to HEV are enzyme immunoassays (EIAs) that use recombinant open reading frame 2 (ORF2) protein expressed in insect cells by the baculovirus system (7, 19). We decided to improve this EIA by making it quantitative and reproducible. We used a highly purified antigen to reduce background signal and standardized it for potency to improve consistency across antigen lots or within a lot over time. We used a reference antibody standard and the four-parameter logistic model (17) for accurate quantitation of antibody potency. We established assay control parameters to ensure consistency.The performance of an EIA is strongly determined by its antigen. Several lines of evidence identify the ORF2 protein as the HEV capsid protein (10,19). When the HEV capsid protein is expressed by using the baculovirus system (rHEV capsid), it assumes a conformation that enables self-assembly into capsomers or particles and confers strong antigenicity (14, 15). The rHEV capsid protein truncated at amin...