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This prespecified subanalysis of the global, randomized controlled phase III KEYNOTE‐024 study of pembrolizumab vs chemotherapy in previously untreated metastatic non‐small‐cell lung cancer without EGFR/ALK alterations and a programmed death ligand 1 (PD‐L1) tumor proportion score of 50% or higher evaluated clinical outcomes among patients enrolled in Japan. Treatment consisted of pembrolizumab 200 mg every 3 weeks (35 cycles) or platinum‐based chemotherapy (four to six cycles). The primary end‐point was progression‐free survival; secondary end‐points included overall survival and safety. Of 305 patients randomized in KEYNOTE‐024 overall, 40 patients were enrolled in Japan (all received treatment: pembrolizumab, n = 21; chemotherapy, n = 19). Median progression‐free survival was 41.4 (95% confidence interval [CI], 4.2‐42.5) months with pembrolizumab and 4.1 (95% CI, 2.8‐8.3) months with chemotherapy (hazard ratio [HR], 0.27 [95% CI, 0.11‐0.65]; one‐sided, nominal P = .001). Median overall survival was not reached (NR) (95% CI, 22.9‒NR) and 21.5 (95% CI, 5.2‐35.0) months, respectively (HR, 0.39 [95% CI, 0.17‐0.91]; one‐sided, nominal P = .012). Treatment‐related adverse events occurred in 21/21 (100%) pembrolizumab‐treated and 18/19 (95%) chemotherapy‐treated patients; eight patients (38%) and nine patients (47%), respectively, had grade 3‐5 events. Immune‐mediated adverse events and infusion reactions occurred in 11 pembrolizumab‐treated patients (52%) and four chemotherapy‐treated patients (21%), respectively; four patients (19%) and one patient (5%), respectively, had grade 3‐5 events. Consistent with results from KEYNOTE‐024 overall, first‐line pembrolizumab improved progression‐free survival and overall survival vs chemotherapy with manageable safety among Japanese patients with metastatic non‐small‐cell lung cancer without EGFR/ALK alterations and a PD‐L1 tumor proportion score of 50% or higher. The trial is registered with Clinicaltrials.gov: NCT02142738., This prespecified subanalysis of the global, randomized controlled phase III KEYNOTE‐024 study of pembrolizumab vs chemotherapy in previously untreated metastatic non‐small‐cell lung cancer without EGFR/ALK alterations and a PD‐L1 tumor proportion score of 50% or higher evaluated clinical outcomes among patients enrolled in Japan. Consistent with results from KEYNOTE‐024 overall, first‐line pembrolizumab improved progression‐free survival and overall survival vs chemotherapy with manageable safety among 40 Japanese patients in the study.

We report an acute clinical course of pneumonia caused by Legionella pneumophila in a patient receiving chemotherapy for lung cancer and corticosteroid therapy. A 57‐year‐old man presented with fever and dyspnoea and was admitted to our hospital. Chest computed tomography revealed a new left lower lung infiltrate, tumour progression in the right upper lung region, metastases to lymph nodes and pleural effusion. The urinary antigen test for Legionella was positive. The patient's oxygen requirement increased on the day of admission, and he died the day after hospitalization. Legionnaires' disease may manifest with an acute presentation, and patients in Japan with physical risk factors for this disease could get infected despite the absence of environmental risk factors. Early treatment for suspected Legionnaire's disease should be considered., Legionnaires' disease may manifest with an acute presentation. Patients with physical risk factors could get infected without environmental risk. Early administration of antibiotics should be considered.

Aim A complete cure for chronic hepatitis B virus (HBV) infection requires elimination of covalently closed circular DNA; however, this remains to be clinically achieved. Interferon (IFN)-γ, a type II IFN, is produced by intrahepatic cytotoxic T lymphocytes and has non-cytolytic antiviral potential. However, the mechanism by which IFN-γ regulates HBV infection has not been fully elucidated. Thus, we developed an in vitro HBV infection assay system and analyzed the molecular signature of HBV regulation by IFN-γ. Methods The in vitro HBV infection assay system was established in primary human hepatocytes infected with HBV derived from the plasmid containing 1.3-mer HBV genome, and treated with IFN-γ. The antiviral effects and signaling pathways of IFN-γ were examined using microarray, and assessed by siRNA knockdown experiments of the related genes. Results IFN-γ treatment suppressed both HBV propagation and transcription as efficiently as IFN-α. Microarray analysis showed that IFN-γ stimulation induced the activation of both IFN-γ and IFN-α signaling, regulating HBV covalently closed circular DNA. HBV production was decreased by IFN-γ through Janus kinase/signal transducer and activator of transcription signaling and interferon-stimulated genes, such as 2'-5'-oligoadenylate synthase 2 and apolipoprotein B mRNA editing enzyme catalytic subunit 3G. Conclusions IFN-γ can suppress HBV propagation and transcription in hepatocytes by activating specific intracellular signaling pathways in hepatocytes, and suggests the future application of these particular signaling pathways or genes for the complete elimination of HBV.

Aim The major transmission mode of hepatitis A virus (HAV) in Japan is the fecal-oral route by contaminated foods. In contrast, HAV infection is well documented as a sexually transmitted disease in Europe and North America. The present study was undertaken to determine the full-genome sequence of HAV and trace the transmission route of HAV in Japanese men who have sex with men (MSM). Methods In 2018, we encountered three Japanese MSM with acute hepatitis A co-infected with HIV for 4-12 years. Serum samples obtained from these patients were used for HAV full-genome analyses. Results Isolated HAV strains were segregated into subgenotype IA. The three HAV strains shared 100% identity within the 481-nucleotide partial sequence. The entire nucleotide sequence showed that the three strains were 99.97% similar to each other with only two nucleotide substitutions. At the amino acid level, the three strains differed from each other by only one or two amino acids. All three strains obtained in the present study were >99.6% identical to the 66 reported strains isolated from Taiwan and European countries during 2015-2017. In addition, these 66 strains include the RIVM-HAV16-090 (EuroPride) strain, which has been involved in HAV outbreaks among MSM worldwide. Conclusions We determined for the first time the full-genome sequence of HAV isolated from Japanese MSM with acute hepatitis A and found that the strains were identical to those from MSM worldwide. Thus, these HAV strains were imported to Japan from foreign countries through MSM.

In January 2012, Mongolia started a hepatitis A vaccination program, which has not yet been evaluated. The first occurrence of autochthonous acute hepatitis E in 2013, caused by genotype 4 hepatitis E virus (HEV), suggests the need for a routine study to monitor its prevalence. One hundred fifty-four consecutive patients who were clinically diagnosed with acute hepatitis between 2014 and 2015 in Ulaanbaatar, Mongolia were studied. By serological and molecular testing followed by sequencing and phylogenetic analysis, only one patient (0.6%) was diagnosed with acute hepatitis A, caused by genotype IA hepatitis A virus (HAV), and 32 (20.8%) patients were diagnosed with acute hepatitis E, caused by genotype 1 HEV. The 32 HEV isolates obtained in this study shared 99.5-100% nucleotide identity and were grouped into a cluster separated from those of subtypes 1a to 1f. Upon comparison of p-distances over the entire genome, the distances between one representative HEV isolate (MNE15-072) and 1a-1f strains were 0.071-0.137, while those between 1b and 1c were 0.062-0.070. In conclusion, the prevalence of acute hepatitis A has decreased in Mongolia since the start of the vaccination program, while the monophyletic genotype 1 HEV strain of a probably novel subtype has been prevalent.

Background The prevalence of occult hepatitis B virus (HBV) infection (OBI) in children who develop the infection via mother-to-child transmission (MTCT) despite immunoprophylaxis remains controversial and is still unknown in Japan. The aim of this study was to determine the OBI prevalence among such children in Japan and identify the genomic mutations that might be associated with the pathogenesis of OBI in children. Methods The data on 158 children born to HBV carrier mothers and who received complete passive-active immunoprophylaxis after birth 2002-2014 were reviewed. HBV markers were detected using commercial enzyme-linked immunosorbent assay kits. HBV DNA was detected using real-time and nested polymerase chain reaction. Complete genomic sequences were determined. Results Among the 158 children studied, 3 experienced HBV-MTCT: 2 had OBI, and 1 had resolved HBV infection (RBI). The prevalence of OBI and RBI was estimated to be 1.3% and 0.6%, respectively. The HBV genomes of the 2 OBI children were wild type and 100% identical to those of their mothers. Of these two children, one received repeated administration of HB immunoglobulin (HBIG) and developed overt HBV infection. Her HBV genome had a G145R mutation in the S gene that might have been induced by HBIG administration. One RBI child was persistently positive for antibody to HBV core antigen (anti-HBc; 10-12 S/CO). Conclusions A low prevalence of OBI was observed in children who received immunoprophylaxis for preventing MTCT in Japan. The development of overt HBV infection in infants with OBI indicates the necessity of close and long-term monitoring. This article is protected by copyright. All rights reserved.

Full-length genomic sequences of hepatitis E virus (HEV) obtained from two consecutive cases of acute self-limiting hepatitis E in a city in northeast Japan were determined. Interestingly, two HEV isolates from each patient shared nucleotide identity of 99.97% in 7 225 nucleotides, and a phylogenetic analysis showed that they formed a cluster of Japanese isolates that is considered as a new HEV subtype 3k. The high similarity of HEV sequences of two isolates from these patients in this study suggested that a subtype 3k HEV strain had spread via a commonly distributed food in the city, possibly pig liver.

Aim To evaluate the clinical and virological features of acute hepatitis E (AH-E) in Gunma prefecture and focus on the hepatitis E virus (HEV) infection in immunocompromised patients. Methods A total of 30 patients with AH-E diagnosed at our Gunma University Hospital, and located in 3-39-15 Showa-machi, Maebashi, Gunma 371-8511 Japan, and its affiliated hospitals from 2004 to 2015, were studied. We evaluated the detailed medical histories, laboratory examinations and virological features of these participants. Results Of the 30 patients, 21 patients were men, with a median age of 61 years. Three of these patients had a history of recent oversea travel. A total of 14 patients had eaten raw or undercooked meat/viscera from animals, and two patients had contracted transfusion-transmitted AH-E. Eight patients were immunocompromised, including those with hematological disease, cancer receiving systemic chemotherapy and kidney transplant or connective tissue disease undergoing immunosuppressive medications. The alanine aminotransferase and total bilirubin levels were more significantly reduced in these immunocompromised patients than in the non-immunocompromised patients. Severe thrombocytopenia, an extra-hepatic manifestation of AH-E, occurred in one case. Among the 22 HEV strains whose subgenotype was determined, two were imported strains (1a and 1f), and 11 strains formed four distinct phylogenetic clusters within subgenotype 3b. The remaining nine strains differed from each other by 9.8–22.4%, and were classified into four subgenotypes (3a, 3b, 3e and 3f). Conclusion Markedly divergent HEV strains (3a, 3b, 3e and 3f) were found to circulate in Gunma. Although immunosuppression appears to play a crucial role in establishing chronic sequels, AH-E in eight immunocompromised patients, including transfusion-transmitted HEV infection in two patients, did not become chronic.

Despite the high endemicity of hepatitis A virus (HAV) in Mongolia, the genetic information on those HAV strains is limited. Serum samples obtained from 935 patients with acute hepatitis in Ulaanbaatar, Mongolia during 2004-2013 were tested for the presence of HAV RNA using reverse transcription-PCR with primers targeting the VP1-2B region (481 nucleotides, primer sequences at both ends excluded). Overall, 180 patients (19.3%) had detectable HAV RNA. These 180 isolates shared 94.6-100% identity and formed four phylogenetic clusters within subgenotype IA. One or three representative HAV isolates from each cluster exhibited 2.6-3.9% difference between clusters over the entire genome. Cluster 1 accounted for 65.0% of the total, followed by Cluster 2 (30.6%), Cluster 3 (3.3%), and Cluster 4 (1.1%). Clusters 1 and 2 were predominant throughout the observation period, whereas Cluster 3 was undetectable in 2009 and 2013 and Cluster 4 became undetectable after 2009. The Mongolian HAV isolates were closest to those of Chinese or Japanese origin (97.7-98.5% identities over the entire genome), suggesting the evolution from a common ancestor with those circulating in China and Japan. Further molecular epidemiological analyses of HAV infection are necessary to investigate the factors underlying the spread of HAV and to implement appropriate prevention measures in Mongolia.

Hepatitis E is considered to be a worldwide public health problem. Although the prevalence of hepatitis E virus (HEV) antibodies in healthy individuals is noted to be 11%, no patients with acute hepatitis E have previously been identified in Mongolia. Three hundred two consecutive patients (183 males and 119 females; median age of 22.0 [Interquartile range: 18.3–25.0] years) who were clinically diagnosed with sporadic acute hepatitis during 2012–2013 in Ulaanbaatar, Mongolia, were studied. By serological and/or molecular approaches, 77 (25.5%), 93 (30.8%), 19 (6.3%), 48 (15.9%), and 12 (4.0%) of the patients were diagnosed with acute hepatitis of types A, B, C, D (superinfection of hepatitis delta virus on a background of chronic hepatitis B virus infection) and E, respectively, while the cause of hepatitis was unknown in the remaining 53 patients (17.5%). The 12 hepatitis E patients had no history of travel abroad in the 3 months before the onset of disease, and lived separately in fixed or movable houses with water supplied via pipe, tank or well, denying transmission from a common water supply. The 12 HEV isolates obtained from the patients showed high nucleotide identities of 99.7–100%, and a representative HEV isolate, MNE13-227, was closest to the Chinese isolates of genotype 4, with the highest identity of 97.3% in the 304-nt ORF2 sequence and 92.1% over the entire genome. The present study revealed the occurrence of autochthonous acute hepatitis E in Mongolia, caused by a monophyletic genotype 4 HEV strain. J. Med. Virol. 88:282–291, 2016. © 2015 Wiley Periodicals, Inc.

A unique European-type HEV strain (HE-JA12-0725) classifiable into subgenotype 3f was recovered from a 66-year-old Japanese female with autochthonous acute hepatitis E, and its entire genomic sequence was determined and characterized. The HE-JA12-0725 strain shared the highest identity of 92.7% with a Spanish swine isolate (EU723514) over the entire genome and possessed a long hypervariable region sequence of 111 amino acids, identical to the 3f strains of European origin. The patient had consumed pork liver obtained via home delivery in Japan approximately two months before the disease onset. These results suggest the circulation of rare 3f HEV strains in Japan. J. Med. Virol. 87:1067–1071, 2015. © 2015 Wiley Periodicals, Inc.

Reactivation of a former hepatitis B virus (HBV) infection can be triggered by immunosuppressive therapy, diseases associated with an immunocompromised state, organ transplantation or the withdrawal of antiviral drugs. Despite the absence of such risk factors, a spontaneous reactivation of HBV replication occurred in two elderly patients with resolved or occult HBV infection. A 73-year-old male underwent coronary artery bypass grafting in October 2008, and was negative for HBsAg but positive for anti-HBs. In July 2009, his serum became positive for HBsAg, HBeAg and HBV DNA (6.4 log copies/ml; genotype C), but negative for anti-HBc IgM, with abrupt elevation of the liver enzymes. The entire genomic sequence of HBV recovered from this patient revealed no mutations in the core promoter and precore regions that interfere with HBeAg production. A 76-year-old male with a history of endoscopic mucosal resection for esophageal cancer in 2002 and an initial diagnosis of diabetes mellitus in 2009, at which time he was negative for HBsAg. He was found to be positive for HBsAg in September 2012 during a laboratory examination performed prior to the resection of recurrent esophageal cancer, despite a low HBV load (2.1 log copies/ml). Three months later, without the administration of any anticancer drugs, the HBV DNA (genotype B) level increased to 5.1 log copies/ml. A precore G1896A variant with high quasispecies diversity was recovered from the patient. Aging, surgical stress and complication of disease(s) associated with compromised immunity, such as cancer, arteriosclerosis and diabetes mellitus may trigger spontaneous HBV reactivation. J. Med. Virol. 87:589–600, 2015. © 2015 Wiley Periodicals, Inc.

We report a female patient with acute hepatitis B due to horizontal transmission of hepatitis B virus from her husband, who suffered from de novo hepatitis B. A 48-year-old man underwent peripheral blood stem cell transplantation (PBSCT) for adult T-cell leukemia/lymphoma. Nine months after the initial treatment, he was referred to our hospital because of jaundice. Laboratory data showed elevated serum aminotransferase levels and hepatitis B surface antigen (HBsAg) positivity. We diagnosed de novo hepatitis B because a pre-PBSCT serum sample was negative for HBsAg and positive for anti-hepatitis B core antibody (HBcAb). His liver function improved with entecavir therapy. Two months after his diagnosis of hepatitis B, his 31-year-old wife was admitted with fever and appetite loss. She was diagnosed with acute hepatitis B because of increased serum aminotransferase levels and HBsAg and immunoglobulin M HBcAb positivity. Sequencing of HBV DNA in the serum obtained from both patients showed 99.9% homology. Therefore, we diagnosed her acute hepatitis B as due to horizontal transmission of de novo hepatitis B from her husband. HBV derived from de novo hepatitis B should be considered a potential source of infection, although intrafamilial transmission of de novo hepatitis B is rare.

Aim To examine the prevalence and characteristics of hepatitis A virus (HAV) and hepatitis E virus (HEV) infections in the northern part of Honshu, Japan, during the last decade. Methods Using the registration system of a prospective cohort study for acute liver injury (ALI) in Iwate and three neighboring prefectures, we examined the prevalence of sporadic acute hepatitis (AH) with HAV (AH-A) and HEV (AH-E) and the distribution of viral genotypes in 487 patients diagnosed with ALI between 2004 and 2013. Results Among all 487 patients, 135 (28%) had ALI with viral infection. In the cases with viral ALI, the prevalence of hepatitis B virus-related AH was highest (55.6%). AH-E was seen in 23 patients (17.0%) and its prevalence was higher than that of AH-A (10 patients, 7.4%). There were no appreciable differences in the prevalence of AH-A and AH-E between 2004–2008 and 2009–2013. However, subgenotype IIIA HAV homologous to Korean strains has recently emerged, and the number of AH-E cases seems to be increasing. HEV genotype 3 was predominant throughout the observation period, but HEV genotype 4 was found in three patients after 2010. The transmission routes of HAV and HEV infections were unknown in approximately 60% of the patients. Conclusion In the northern part of Honshu, Japan, HEV has been more frequently implicated in the development of AH than HAV, and HEV genotype 4 has been recently increasing. To provide an effective prophylactic management for HAV and HEV infections, further clarification of the transmission routes is needed.

A 71-year-old (C1I) and 69-year-old (C2I) Japanese female contracted fulminant hepatitis B after 50 and 49 years of marriage, respectively. Both index cases exhibited high levels of anti-HBc IgM antibodies (24.2 and 31.5 S/CO, respectively), suggestive of acute hepatitis B virus (HBV) infection, although they had no discernible risk factors for HBV infection, except for chronically HBV-infected spouses with detectable HBV DNA (3.3 log copies/ml [C1S: 72-year-old] and 7.2 log copies/ml [C2S: 71-year-old]). The HBV genotype/subgenotype was identical in each couple (B/B1 or C/C2). The HBV isolates from the index cases and spouses shared a nucleotide sequence identity of 99.5% and 99.7%, respectively, over the entire genome, and these four isolates had the highest nucleotide sequence identity of only 97% to HBV isolates deposited in DNA databases. Phylogenetic trees confirmed a close relationship of the HBV isolates between C1I and C1S and between C2I and C2S, supported by a high bootstrap value of 100% within each couple, indicating the transfer of HBV infection between spouses. These four isolates shared a precore mutation of G1896A known to be associated with fulminant hepatitis B. Although the history of sexual contact within a reasonable incubation period was obscure for one stable, monogamous couple (C1I and C1S), the other couple had a monogamous sexual relationship within six months prior to disease onset. This study indicates that two elderly Japanese patients with fulminant hepatitis B acquired HBV infection via interspousal (most likely sexual) transmission during long-lasting marriages.

Aim To characterize hepatitis E in Mie prefecture and to investigate whether raw pig liver sold as food in Mie is contaminated with hepatitis E virus (HEV) strains similar to those recovered from patients. Methods Seventeen patients with sporadic acute hepatitis E treated from 2004 to 2012 were studied. A total of 243 packages of raw pig liver from regional grocery stores were tested for the presence of HEV RNA. The partial genomic sequences of human and swine HEV isolates were determined and subjected to the phylogenetic analyses. Results The HEV isolates recovered from the 17 patients segregated into genotype 3 (n = 15) and genotype 4 (n = 2), and 15 genotype 3 isolates further segregated into 3e (n = 11) and 3b (n = 4). Pig liver specimens from 12 (4.9%) of the 243 packages had detectable HEV RNA. All 12 swine HEV isolates were grouped into genotype 3 (3a or 3b). Although no 3e strains were isolated from pig liver specimens, two 3b swine strains were 99.5–100% identical to two HEV strains recovered from hepatitis patients, within 412-nt partial sequences. Conclusion The 3e HEV was prevalent among hepatitis E patients. HEV RNA was detected in approximately 5% of pig liver sold as food. The presence of identical HEV strains between hepatitis patients and pig liver indicated that pigs play an important role as reservoirs for HEV in humans in Mie. Further studies are needed to clarify the source of 3e HEV in the animal and environmental reservoirs.

In Japan, hepatitis E had long been considered to be a rare liver disease which can be accidentally imported from endemic countries in Asia and Africa, where the sanitation conditions are suboptimal. However, since the identification of the first autochthonous hepatitis E case and hepatitis E viremic domestic pigs in Japan in 2001, our understanding of hepatitis E virus (HEV) infection in this country has been changing markedly. This has largely been due to the development of serological and gene-based diagnostic assays, the accumulation of molecular epidemiological findings on HEV infection in humans and animals (as potential reservoirs for HEV in humans) and the recognition of the importance of zoonotic food-borne and other routes of transmission of HEV, including blood-borne transmission. Although it is now evident that autochthonous hepatitis E in Japan is far more common than was previously thought, clinical and subclinical HEV infections indigenous to Japan remain underdiagnosed and their prevalence is still underestimated due to the presence of unknown transmission routes and a low awareness of the infection status by many physicians in Japan. This review focuses on the features of HEV infection in humans and animals, as definitive or potential reservoirs for HEV, in Japan, and updates the current knowledge on the routes of transmission, including zoonotic routes, which are important for the maintenance and spread of HEV in Japan.

A 67-year-old male living in Tsu city, Mie prefecture, Japan was referred to our hospital for further examination of acute liver injury and was diagnosed as having clinical hepatitis E virus (HEV) infection in January 2010. The HEV strain (HE-JA11-1701) isolated from the patient belonged to genotype 3 and European-type subgenotype 3e. It was presumed that the patient had been infected from a wild boar (Sus scrofa leucomystax) because he consumed meat/viscera from a wild boar that he had captured himself as a hunter approximately 2 months before disease onset. A specimen of the boar meat/viscera that the patient had ingested was not available. However, the HE-JA11-1701 strain was 99.8% identical within the 412-nucleotide sequence of the open reading frame 2 region to a HEV strain (JBOAR012-Mie08) that had been recovered from a wild boar captured near the patient's hunting area in 2008. A phylogenetic analysis confirmed that the two HEV strains had a close genetic relationship and were segregated into subgenotype 3e, supported by a high bootstrap value of 99%. Of note, the HE-JA11-1701 and JBOAR012-Mie08 strains were remotely related to the 3e strains reported in Japan and European countries, with a nucleotide difference of 7.9-13.9%, reinforcing the uniqueness of the 3e strains obtained in the present study. These results strongly support our speculation that the patient developed acute hepatitis E via consumption of HEV-infected boar meat/viscera. Genetic analyses of HEV strains are useful for tracing infectious sources in sporadic cases of acute hepatitis E.

Aim Hepatitis A virus (HAV) is the most common cause of infectious hepatitis worldwide. Although hepatitis A cases imported from South-East Asian countries, including the Philippines, have been reported in Japan, the molecular epidemiological data have been limited for these HAV-endemic countries. Methods The full-length genomic sequences of HAV isolates were determined and subjected to the phylogenetic analyses. Results The HAV isolates (HA12-0796 and HA12-0938) obtained from two Japanese patients who developed acute hepatitis A in July 2012, 1 month after traveling to the Philippines, where they consumed undercooked shellfish, differed by only one nucleotide (nt) over the entire genome. These HAV isolates of genotype IA were 99.1–99.5% identical within 228–237 nt to those recovered from river water in the Philippines, suggesting that the HA12-0796 and HA12-0938 isolates represent HAV circulating in the Philippines. HAV isolates belonging to one of the two IA sublineages (IA-2) which were implicated in some of the mini-epidemics in 2010 in Japan are hypothesized to be connected with the Philippines. In support of this speculation, the present IA isolates (HA12-0796 and HA12-0938) shared 98.8% identity over the entire genome with one IA-2 isolate (HAJIH-Fukuo10) recovered from a Japanese female who developed a domestic HAV infection during the mini-epidemics. In the phylogenetic tree constructed based on the entire genome, these three isolates (HA12-0796, HA12-0938 and HAJIH-Fukuo10) segregated into a cluster with a bootstrap value of 100%. Conclusion These results indicate that HAV isolates belonging to the IA-2 lineage might have been imported from the Philippines.

Quantum dot superlattices (QDSLs) are attractive for artificial crystal applications, and QDSLs fabricated via solution-based methods show excellent potential for printed electronics, particularly for large-area optoelectronic devices such as flat-panel light-emitting devices (LEDs), lighting, and solar cells. In this paper, we propose percolative QDSLs (P-QDSLs), where quantum dots (QDs) are randomly dispersed in a host material, and if the QD volume fraction exceeds the percolation threshold, then percolation paths form naturally via the QDs. The P-QDSL is therefore a random QDSL involving configurational disorder. We demonstrate the formation of P-QDSLs using ZnO/MgO core/shell QDs fabricated via a solution-based method and give preliminary results for their application to the printed emission layer in LEDs (© 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)

Background Since previous studies have investigated the population dynamics of Japan-indigenous genotype 3 hepatitis E virus (HEV) using virus sequences, more nucleotide sequences have been determined, and new techniques have been developed for such analysis. Aims To prevent future hepatitis E epidemic in Japan, this study aimed to elucidate the cause of past HEV expansion. Methods The epidemic history of Japan-indigenous genotype 3 HEV was determined using the coalescent analysis framework. Bayesian skyline plot (BSP) and Bayesian estimate of phylogeny with relaxed molecular clock models were calculated using Markov chain Monte Carlo sampling. Results Japan-indigenous strains consist of New World strains (subtype 3a), Japanese strains (3b) and European strains (3e). The oldest lineage, 3b, appeared around 1929. Lineages 3a and 3e appeared around 1960. BSPs indicated similar radical population growth of the 3a and 3b lineages from 1960 to 1980. Conclusions Population dynamics of the three lineages shared some common characteristics, but had distinguishing features. The appearance of 3a and 3e lineages coincides with the increase of large-race pig importation from Europe and the USA after 1960. The epidemic phase of 3a and 3b strains from 1960 to 1980 could be related to increased opportunity for HEV infection arising from large-scale pig breeding since 1960. Our observations revealed new findings concerning the close relationship between the epidemic history of Japan-indigenous genotype 3 HEV and the improvement of the Japanese pig industry. Infection control in pig farms should be an effective method of preventing HEV infection in humans.

Attempts have been made to propagate hepatitis E virus (HEV) in primary hepatocyte culture and various other cultured cells. However, the replication ability of HEV recovered from culture media remains extremely low. Recently, efficient culture systems have been established in PLC/PRF/5 (hepatocellular carcinoma) and A549 (lung cancer) cell lines for HEV strains of genotypes 3 and 4 in our laboratory. They originated in fecal extracts from patients containing HEV RNA in extremely high-titers (107 copies/ml), and named the JE03-1760F (genotype 3) and HE-JF5/15F (genotype 4) strains, respectively. HEV RNA in culture supernatants reached 108 copies/ml in titer, and were transmitted successively through many passages. An infectious HEV cDNA clone (pJE03-1760F/wt) was constructed that has replication activity comparable to that of the wild-type JE03-1760F in feces. The ORF3 protein is indispensable for shedding HEV particles from cells in the reverse genetics system. HEV recovered from culture media, as well as circulating HEV, possess ORF3 proteins on the surface and are covered with cellular membranes, and therefore, ORF2 epitopes are buried in these particles. In contrast, HEV excreted into feces are naked nucleocapsids without a lipid layer or surface expression of the ORF3 protein. HEV in sera of patients with acute hepatitis E can infect and replicate in PLC/PRF/5 and A549 cells, with efficiency comparable to the circulating HEV RNA levels. High-efficiency cell culture systems for infectious viruses, thus developed, are expected to open up a new era and resolve many mysteries in the epidemiology, molecular biology, and treatment of HEV. Copyright © 2011 John Wiley & Sons, Ltd.

Two novel subgenotypes (C6 and D6) of hepatitis B virus (HBV) were identified recently in Papua, a multiethnic area of Indonesia. To characterize further the HBV strains in Papua, serum samples collected from 59 viremic subjects (44 males and 15 females; mean age: 30.0 ± 15.5 years) among indigenous inhabitants in Papua, were subjected to phylogenetic analysis of an 1.6-kb partial sequence. Forty-five samples (76%) had genotype C HBV (HBV/C) [C5 (n = 1), C6 (n = 40), and unclassifiable (n = 4)], while seven samples (12%) were HBV/D [D1 (n = 1) and D6 (n = 6)] and six samples (10%) were HBV/B [B2 (n = 1), B3 (n = 3), B7 (n = 1), and B8 (n = 1)]; the remaining sample possessed B3 and C6. An analysis of the full-length sequence of the four HBV/C isolates (NMB09122, NMB09124, NMB09075, and MRK89073) that were unclassifiable into any of the 10 known HBV/C subgenotypes (C1-C10) showed no significant evidence of recombination. Over the entire genome, the NMB09122 and NMB09124 isolates shared 99.8% identity and segregated into a cluster with a bootstrap value of 100%, differing from HBV/C1-HBV/C10 by 3.8-6.9% (mean, ≥4.0%), indicating that NMB09122 and NMB09124 can be classified into a novel subgenotype within genotype C (tentatively designated C11). The NMB09075 and MRK89073 isolates were 97.4% identical to each other and differed from known HBV/C isolates, including the C11 strains, by 4.0-7.2% (mean, ≥4.5%) over the entire genome, indicating that NMB09075 and MRK89703 can be classified into another novel HBV/C subgenotype (C12). The distribution of C11 and C12 seemed to be associated with particular language speakers in Papua.

Surface-heating phenomenon by the radiation from high density plasma during growth of microcrystalline silicon (μc-Si:H) thin films at high rate (> 5 nm/sec) is one of the crucial issues to be solved for obtaining high quality intrinsic-layer material for solar cells. We have utilized an optical emission spectroscopy (OES) in the plasma to observe the time evolution of gas temperature during film growth as well as the film-growth rate under μc-Si:H deposition conditions at high rate. Gas temperature has been successfully controlled by changing total flow rate of monosilane (SiH4)/hydrogen (H2) gas mixture, leading to a drastic improvement of optoelectronic properties in the resulting μc-Si:H. (© 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)

Light trapping is a crucial technique for increasing the photocurrent of solar cells, particularly that of microcrystalline (μc-Si) thin-film solar cells. Transparent conductive oxides with rough surfaces such as Al-doped ZnO (AZO) have been used extensively for this purpose. In general, the surface morphology influences the film growth and photovoltaic performance; on extremely rough surfaces the photovoltaic performance deteriorates. In this article, the experimental results of photoacoustic (PA) spectroscopy, performed on μc-Si films deposited on various AZO surfaces, are presented as a function of AZO surface roughness σRMS, together with those derived from electron spin resonance. The amplitudes of the PA signals at 1.4 eV increased significantly when σRMS = 22 nm, a roughness where cracks were not observed in the μc-Si. The amplitudes of the PA signals at 0.9 eV and the spin densities showed sigmoidal increases centered at a critical roughness of around 30 nm. (© 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)

To investigate nationwide the prevalence of hepatitis E virus (HEV) infection in the general population of Japan, serum samples were collected from 22,027 individuals (9,686 males and 12,341 females; age, mean +/- standard deviation: 56.8 +/- 16.7 years; range: 20-108 years) who lived in 30 prefectures located in Hokkaido, mainland Honshu, Shikoku, and Kyushu of Japan and underwent health check-ups during 2002-2007, and were tested for the presence of IgG, IgM, and IgA classes of antibodies to HEV (anti-HEV) by in-house ELISA and HEV RNA by nested RT-PCR. Overall, 1,167 individuals (5.3%) were positive for anti-HEV IgG, including 753 males (7.8%) and 414 females (3.4%), the difference being statistically significant (P0.0001). The prevalence of anti-HEV IgG generally increased with age and was significantly higher among individuals agedor=50 years than among those aged50 years (6.6% vs. 2.7%, P0.0001). Although 13 individuals with anti-HEV IgG also had anti-HEV IgM and/or anti-HEV IgA, none of them had detectable HEV RNA. The presence of HEV RNA was further tested in 50 or 49-sample minipools of sera from the remaining 22,014 individuals, and three individuals without anti-HEV antibodies tested positive for HEV RNA. The HEV isolates obtained from the three viremic individuals segregated into genotype 3 and were closest to Japan-indigenous HEV strains. When stratified by geographic region, the prevalence of anti-HEV IgG as well as the prevalence of HEV RNA or anti-HEV IgM and/or anti-HEV IgA was significantly higher in northern Japan than in southern Japan (6.7% vs. 3.2%, P0.0001; 0.11% vs. 0.01%, P = 0.0056; respectively).

Optical-emission-intensity ratio of during film growth has been used as a simple indicator to predict crystallinity (crystal-volume fraction: XC) in the resulting microcrystalline silicon (µc-Si:H) thin films. The relationship between and XC has been checked under a wide variety of film-preparation conditions including low-deposition-rate ( 5 nm/s) cases. On the basis of theoretical consideration, we have proposed optical-emission-intensity ratio of as a new indicator of XC during film growth of µc-Si:H.

Universal Meyer-Neldel (MN) relations in the reciprocal temperature domain are derived on the basis of Laplace transform representation of thermally activated quantities, by a mathematical analogy to the generalized Kramers-Kronig relations in the frequency domain. We concern the circumstances that allow the MN rule to be experimentally observed in realistic physical systems within the context of the Fano resonant-transition model incorporating Yelon's multi-excitation concept.

BACKGROUND: Screening blood donors for hepatitis C virus (HCV) antibody has effectively mitigated transfusion transmission of HCV. We conducted a post hoc analysis to clarify the impact of donor screening on a general population of reproductive-age females and their offspring. STUDY DESIGN AND METHODS: Anti-HCV screening in Japan started in late-1989. In a cohort studied between May 1990 and November 2004, a total of 22,664 consecutive serum samples from pregnant women were screened for anti-HCV. Reactive samples were further tested for HCV RNA. Linear structural regression was applied to identify causal relationships. RESULTS: Anti-HCV–reactive rates declined significantly by two measures. First, among women known to have been transfused, rates fell from 14.8% to 3.1% with the implementation of anti-HCV screening (p

A 23-year-old nurse (HC-IP) developed acute hepatitis C. Intrafamilial transmission of hepatitis C virus (HCV) was suspected initially because her parents were carriers of HCV of the same genotype (1b) as that of Patient HC-IP. However, the HCV isolate from Patient HC-IP and those from her parents shared identities of only 92.4-92.7% in the 1,087-nucleotide (nt) sequence within the NS5B region. It was then suspected that she contracted HCV infection during medical practice. Sixteen patients with antibodies to HCV (anti-HCV) were hospitalized 1-3 months before she became positive for anti-HCV. Upon analysis of stored serum samples, 14 of the 16 patients were found to be positive for HCV RNA, and 9 of the 14 viremic patients had genotype 1b HCV. Although the shared identities between the HCV isolate from Patient HC-IP and those from eight of the nine patients were merely 90.6-93.9% within the 1,087-nt NS5B sequence, the HCV isolate from the remaining one patient (HC-P12) was 99.7% identical to that from Patient HC-IP. Upon analysis of the E1 and E2 junctional region including hypervariable region 1 (283 nt), there was a close relationship (99.3-100%) between clones obtained from Patients HC-IP and HC-P12. Although the nurse HC-IP had a finger injury, she took care of Patient HC-P12, a 70-year-old man with HCV-related cirrhosis and recurrent epistaxis, occasionally without wearing protective gloves. This study indicates the occurrence of HCV transmission by exposure of nonintact skin to blood in health care settings.

The effect of recombinant interferon-alfa on serum HCV RNA levels in Japanese patients with chronic hepatitis C was investigated. At 24 weeks of treatment, 41 (32.5%) of 126 patients lost HCV RNA from serum, and aminotransferases were normalized in 31 (75.6%) of these 41 cases. HCV genotypes were categorized into four types (Type I, II, III, IV); the frequencies among the patients were: Type I: 0%, Type II: 70.6%, Type III: 20.6%, and Type IV: 6.3%. At the end of the 24-week treatment, HCV RNA levels were remarkably decreased in Type III patients and became undetectable in 18 (69.2%) of 26. In contrast, only 18 (20.2%) of 89 patients with Type II and two of eight with Type IV lost HCV RNA from sera. The relation between HCV genotype (Type III) and response to IFN therapy was also confirmed using a logistic regression model. HCV genotype seems to be an important factor in determining the response to IFN in patients with chronic hepatitis C.

We have studied nanostractured (NS-) thin-film electroluminescent (TFEL) devices utilizing the ZnS nanocrystals (NCs) with the mean crystal sizes of of ca. 2-4 nm doped with activator-ions. As compared to the conventional TFEL device, we have achieved a remarkable reduction in the operation volt-ages by >100 V 0-p . Moreover, toward full-color emissions, emissions of three primary colors, i.e., red, green, and blue have been derived from Mn 2+ , Tb 3+ , and Tm 3+ ions, respectively. In this article, we review the studies on the fundamental properties of ZnS NCs as well as the device performance of the NS-TFEL devices. We also discuss the excitation mechanisms of the activator-ions in the ZnS NCs.

A 65-year-old Japanese man was hospitalized because of acute hepatitis and severe cholestasis due to hepatitis E virus (HEV) infection combined with a drug reaction to a cold preparation. He died of disseminated intravascular coagulation and severe intestinal bleeding due to systemic cytomegalovirus reactivation following the development of severe eruptions with marked eosinophilia due to drug hypersensitivity to taurine and ursodeoxycholate preparations. The close interaction between viral infection or reactivation and drug hypersensitivity was considered as a pathophysiology in this case, which emphasizes the need for further study of the immunological mechanism of the interaction.

Although no outbreaks of hepatitis E have been reported in Mongolia, a significant proportion of the general population had antibodies to hepatitis E virus (HEV). To investigate whether pigs are possible reservoirs of HEV in Mongolia, serum samples obtained from 243 2- or 3-month-old pigs on four swine farms surrounding Ulaanbaatar, the capital city of Mongolia, were tested for the presence of anti-HEV antibodies and HEV RNA. Overall, 223 pigs (91.8%) tested positive for anti-HEV, while 89 pigs (36.6%) had detectable HEV RNA. The 89 HEV isolates obtained from the viremic pigs were 78.7-100% identical to each other, and 80.9-85.9% similar to the prototype genotype 3 HEV isolate (US1) in the 412-nucleotide (nt) sequence within open reading frame 2. They were classified into two novel phylogenetic groups within genotype 3, differing by 16.4-21.3%. The swMN06-A1288 and swMN06-C1056 isolates, representing each of the two clusters within genotype 3, had a genomic length of nucleotides (nt) 7,222 nt and 7,223 nt, respectively, excluding the poly(A) tail, and shared only 81.6% over the entire genome. Upon comparison with the 25-reported genotype 3 HEV isolates over the entire genome, swMN06-A1288 had identities of merely up to 84.9%, while swMN06-C1056 of only up to 85.9%. Phylogenetic analysis confirmed the remote relatedness of the Mongolian swine isolates to the genotype 3 HEV isolates reported thus far. These results indicate that farm pigs in Mongolia are frequently infected with presumably indigenous HEV strains of genotype 3 and could be a source of HEV infections in humans in Mongolia.

Mongolia is highly endemic for hepatitis B virus (HBV), hepatitis C virus (HCV), and hepatitis delta virus (HDV) infections among apparently healthy adults. However, the age-specific prevalence of ongoing HBV, HCV, and HDV infections among children in Mongolia remains unknown. Therefore, samples obtained from a total of 655 apparently healthy children of 0.3-15 years of age (307 boys and 348 girls; age, mean +/- standard deviation [SD], 8.4 +/- 4.2 years) living in Mongolia, between October 2005 and January 2006, were tested for serological and molecular markers of HBV, HCV, and HDV infections. Although 88.7% of the 655 children studied were immunized against hepatitis B, 64 (9.8%) tested positive for hepatitis B surface antigen (HBsAg) and/or HBV DNA and 13 (2.0%) for HDV RNA. Twenty-seven children (4.1%) had detectable HCV RNA. Collectively, 82 (12.5%) were viremic for one or more of these viruses, including eight children with dual viremia of HBV/HCV and one child with triple HBV/HCV/HDV viremia. When children without anti-HBc, anti-HCV and anti-HDV IgG (n = 510) served as a control, a history of hospitalization was significantly associated with HBV viremia (P < 0.0001), anti-HBc positivity (P < 0.0001), and HCV viremia (P = 0.0001). HBsAg mutation was found in 18 (31.6%) of the 57 children with viremia, including those at amino acid position 126, 127, 129, 131, 134, 143 or 144. There were no significant differences in the frequency of HBsAg mutation in relation to age, sex, and hepatitis B vaccination status of the children, suggesting that HBsAg mutation plays a limited role in failure of vaccination in Mongolia.

The wavelength dependence of the third-order optical nonlinearity and response of the J-like aggregates of a cyanine dye called NK-3261 in a neat film were measured by the femtosecond degenerate four-wave mixing (DFWM) technique under resonant conditions. The temporal profile of the DFWM signal of NK-3261 J-like aggregates was found to consist of three components, i.e., coherent instantaneous nonlinear response (electronic response) and the two slow responses with decay time constants of ca. 0.9 ps and ca. 5.6 ps. The electronic component of the effective third-order nonlinear optical susceptibility, χ(3)e, of NK-3261 J-like aggregates was as high as ca. 5 × 10−7 esu at 850 nm. (© 2005 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)

Background: There is little data on the evolution of hepatitis C virus (HCV) quasispecies in infants infected by mother-to-infant transmission during long-term follow up. The hypervariable region 1 (HVR1) of the HCV genome was investigated in two mother–infant pairs from birth to 7.6 and 10.2 years, respectively. Methods: Ten cDNA clones of HVR1 generated from HCV-RNA and extracted from serum samples of both pairs were analyzed. The sequences were compared with regard to variability, identity, and hydrophobia profile, and analyzed by phylogenetic studies. Results: The alanine aminotransferase (ALT) level was high with fluctuation in infant A and almost within the normal range in infant B. Sequence diversity was higher in infant A at 7.6 years than in infant B at 9.3 years (sequence identity with the mothers’; 69.3–70.7% vs 85.3–90.7% for nucleotides, and 48% vs 68–72% for amino acids, respectively). Compared to the first samples, amino acid changes greatly increased in infant A (35.2% at 4.9 years and 52% at 7.6 years), but not in infant B (4% at 5.6 years and 27.5% at 9.3 years). Phylogenetic studies revealed that quasispecies in infant A evolved to a greater extent than that in infant B. Hydrophobia profile analyses revealed that dynamic shifts between hydrophilia and hydrophobia occurred in both infants. Conclusions: As in adults, the evolution of HVR1 and variability of quasispecies increased in infants infected through mother-to-infant transmission for 10 years after birth. A large episode of ALT elevation suggested the emergence of escape mutants and the evolution of new quasispecies.

Background and Aim: Hepatitis C virus (HCV)-infected patients who responded to interferon (IFN) treatment with clearance of serum HCV RNA may rarely develop hepatocellular carcinoma (HCC). The aim of the present study was to elucidate the risk factors for liver carcinogenesis among such patients. Methods: In total, 126 patients with chronic hepatitis C (CHC) who achieved a sustained virological response (SVR) to IFN monotherapy, which was defined as the absence of detectable HCV RNA in the serum at 6 months after completion of treatment, were enrolled and possible risk factors for HCC were analyzed. Results: During the observation period of 66 ± 36 months after cessation of IFN treatment, five (4.0%) of the 126 patients developed HCC. The cumulative incidence of HCC at 3, 5 and 10 years was estimated to be 0.9, 4.7 and 7.5%, respectively. The cumulative incidence of HCC was significantly higher among patients with severe fibrosis (F3 or F4) than among patients with no or mild fibrosis (F0 to F2) in the liver before treatment (P = 0.007); among patients with alcohol intake of ≥ 27 g/day than among patients with that of

Subclinical hepatitis E virus (HEV) infection among healthy individuals was studied serologically and molecularly. Serum samples collected at screening between March and April 2004 (or just before retirement) from 266 medical staff members (35 males, 231 females) who had been working for 8.8 ± 8.5 (mean ± standard deviation, range, 0.3–35.1) years in a city hospital in Japan and serum samples that had been collected from these staff members at the start of employment were tested for IgA, IgM, and IgG antibodies to HEV (anti-HEV) by in-house enzyme-linked immunosorbent assays. Overall, six subjects (2.3%) tested positive for anti-HEV IgG at the screening; among them, four subjects (1.5%) had already been positive for anti-HEV IgG at the start of employment and two subjects (0.8%) seroconverted after initiation of employment. Periodic serum samples that had been collected from the two seroconverted subjects were tested for HEV antibodies and HEV RNA. The two subjects became positive for anti-HEV IgG in 1978 or 2003, respectively, with no discernible elevation in alanine aminotransferase (ALT) level, and continued to be seropositive up through the screening date. Although anti-HEV IgM was not detectable in the two subjects, one was infected transiently with Japan-indigenous HEV strain of genotype 3 and the other was positive transiently for anti-HEV IgA. The present study indicates that even an individual with subclinical HEV infection had evidence of transient viremia in the absence of ALT elevation and that anti-HEV IgA detection may be useful for serological diagnosis of recent subclinical HEV infection. J. Med. Virol. 76:526–533, 2005. © 2005 Wiley-Liss, Inc.

Hepatitis E in industrialized countries has not been well studied. To define the possible risk factors for transmission of hepatitis E virus (HEV) and for the severe form of hepatitis E in Japan, we investigated the clinical and virological characteristics of hepatitis E in 32 patients who contracted the mild (n = 23) or severe form (n = 9) of domestically acquired hepatitis E between 1996 and 2004 in Hokkaido, where hepatitis E is most prevalent in Japan. Nine patients with the severe form of hepatitis E included two patients with fulminant hepatitis E and seven patients who were diagnosed with severe acute hepatitis in which hepatic encephalopathy did not appear during the course of the illness despite low plasma prothrombin activity (≤40%) and/or increased total bilirubin level (≥20 mg/dl). At least 25 patients (78%) had consumed uncooked or undercooked pig liver and/or intestine 1–2 months before the onset of hepatitis E. When compared with the seven patients with HEV genotype 3, the 25 patients with HEV genotype 4 had a higher peak alanine aminotransferase (ALT) level (P = 0.0338) and a lower level of lowest prothrombin activity (P = 0.0340). The severe form of hepatitis E was associated with the presence of an underlying disease (56% [5/9] vs. 17% [4/23], P = 0.0454). The study suggests that zoonotic food-borne transmission of HEV plays an important role in the occurrence of hepatitis E in Hokkaido, Japan, and that the HEV genotype and the presence of an underlying disease influence the severity of hepatitis E. J. Med. Virol. 76:341–349, 2005. © 2005 Wiley-Liss, Inc.

Risk factors for acquiring hepatitis E among individuals in industrialized countries including Japan are not fully understood. We investigated whether Japanese blood donors with or without an elevated alanine aminotransferase (ALT) level are likely to have hepatitis E virus (HEV) infection. Serum samples were collected from 5,343 voluntary blood donors including 1,087 donors with elevated ALT of 61–966 IU/L and 4,256 donors with normal ALT (≤60 IU/L) at two Japanese Red Cross Blood Centers, and were tested for the presence of anti-HEV IgG by in-house enzyme-linked immunosorbent assay (ELISA). Overall, 200 donors (3.7%) were positive for anti-HEV IgG, including 32 (2.9%) with elevated ALT and 168 (3.9%) with normal ALT. Serum samples with anti-HEV IgG were further tested for the presence of anti-HEV IgM by in-house ELISA and for HEV RNA by reverse transcription (RT)-polymerase chain reaction (PCR). Three donors with ALT of 966, 62 or 61 IU/L were positive for anti-HEV IgM and HEV RNA. The HEV isolates obtained from the three viremic donors segregated into genotype 3, were 91.5–93.4% similar to each other in the 412 nucleotide sequence of open reading frame 2, and had the highest identity of 91.5–94.9% with the JRA1 isolate which was recovered from a Japanese patient with sporadic acute hepatitis E who had never been abroad, suggesting that these three HEV isolates are indigenous to Japan. This study suggests that a small but significant proportion of blood donors in Japan with or without elevated ALT are viremic and are potentially able to cause transfusion-associated hepatitis E. J. Med. Virol. 73:554–561, 2004. © 2004 Wiley-Liss, Inc.

In Indonesia where hepatitis E virus (HEV) is believed to be highly endemic, only three outbreaks of HEV transmission have been documented to date in restricted areas (West Kalimantan and East Java). A total of 1,115 serum samples collected from apparently healthy individuals in Bali, Lombok, and Surabaya in Indonesia in 1996 where epidemic HEV transmissions have never been reported, were tested for IgG class antibodies to HEV (anti-HEV). In Bali, anti-HEV was detected in 20% (54/276) of the tested population, in remarkable contrast with 4% (17/446) in Lombok and 0.5% (2/393) in Surabaya. On the other hand, antibodies to hepatitis A virus were highly prevalent in all three regions (95% in Bali, 90% in Lombok, and 89% in Surabaya). Although the majority of the population in Indonesia is Moslem, Balinese people are mostly Hindu and have a habit of consuming pork. Therefore, serum samples were obtained from the 99 farm pigs in Bali and tested for anti-HEV and HEV RNA. The sera from 71 pigs (72%) were positive for anti-HEV and a 2-month-old pig had detectable HEV RNA. The swine HEV isolate recovered from the viremic pig was named SB66-Bali. The SB66-Bali isolate was most closely related to the genotype 4 isolates from China, India, Japan, and Taiwan, but shared only 82.6-90.0% identity in the common 241-412 nucleotides within open reading frame 2 (ORF2). These results indicate that a presumably indigenous HEV strain(s) is circulating in Bali, Indonesia and that HEV infection may occur via zoonosis even in developing countries.