Ongoing subclinical infection of hepatitis E virus among blood donors with an elevated alanine aminotransferase level in Japan

Ongoing subclinical infection of hepatitis E virus (HEV) has not been fully studied. In the present study, serum samples were collected from 6700 voluntary blood donors with an elevated alanine aminotransferase (ALT) level of 61-476 IU/l at a Japanese Red Cross Blood Center, 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, 479 blood donors (7.1%) were positive for anti-HEV IgG, including 8 donors with anti-HEV IgM and 7 donors with anti-HEV IgA. Among the nine donors with anti-HEV IgM and/or anti-HEV IgA, six had detectable HEV RNA. The presence of HEV RNA was further tested in 10-sample minipools of sera from the remaining 6691 donors, and three donors including one without anti-HEV IgG were found to be positive for HEV RNA. When stratified by ALT level, the prevalence of HEV RNA was significantly higher among the 109 donors with ALT > or = 201 IU/l than among the 6591 donors with ALT of 61-200 IU/l (2.8% vs. 0.1%, P < 0.0001). The HEV isolates obtained from the nine viremic donors segregated into genotype 3, shared a wide range of identities of 85.6-98.5% and were 87.3-93.9% similar to the Japan-indigenous HEV strain (JRA1), in the 412-nucleotide sequence of open reading frame 2. This study suggests that approximately 3% of Japanese individuals with ALT > or = 201 IU/l have ongoing subclinical infection with various HEV strains.     

Novel approach for detection of hepatitis E virus infection in German blood donors

The risk of transfusion-transmitted hepatitis E virus (HEV) infections by contaminated blood products remains unknown. In the present study, we evaluated and compared different nucleic acid amplification technique (NAT) methods for the detection of HEV in blood components. Minipools of a total of 16,125 individual blood donors were screened for the presence of HEV RNA using the highly sensitive RealStar HEV RT-PCR kit, revealing a minimum detection limit of 4.66 IU/ml. Thirteen donors were HEV RNA positive (0.08%), and of these donors, only three already showed reactive IgM antibody titers. The detected HEV strains all belonged to genotype 3 and were most closely related to German HEV strains from wild boars and pigs as well as from human hepatitis E cases. Furthermore, HEV RNA and HEV-specific IgM and IgG titers were determined in 136 blood donors with elevated alanine aminotransferase (ALT) levels and in 200 donors without pathological findings. HEV RNA was not detectable, but 8.08% (elevated ALT) and 0.5% (nonelevated ALT) of donors showed reactive HEV IgM titers. The overall seroprevalence rate of HEV IgG amounted to 5.94% (elevated ALT, 5.88%; nonelevated ALT, 6.0%). The clinical relevance of transfusion-associated hepatitis E infection still requires further investigation. However, in connection with raising concerns regarding blood safety, our NAT method provides a sensitive possibility for HEV testing.     

Unchanged high prevalence of antibodies to hepatitis E virus (HEV) and HEV RNA among blood donors with an elevated alanine aminotransferase level in Japan during 1991–2006

Hepatitis E is rare in Japan but is occurring more frequently than previously thought. To investigate whether de novo subclinical infection of hepatitis E virus (HEV) has recently increased in Japan, HEV RNA was assayed in serum samples obtained from 4019 Japanese voluntary blood donors with alanine aminotransferase (ALT) of > or =61 IU/l, who are likely to have ongoing HEV infection, during 1991-2006. The overall rates of IgG-class antibody to HEV (anti-HEV IgG), anti-HEV IgM/IgA and HEV RNA among 3185 donors in 2004-2006 were comparable with those among 594 donors in 1998 (5.3 vs. 5.2%, 0.2 vs. 0.5%, and 0.2 vs. 0.3%, respectively). Among blood donors with ALT > or = 201 IU/l in three groups according to the year of blood collection (1991-1995 [n = 156], 1996-1999 [n = 116] and 2004-2006 [n = 61]), there were no appreciable differences in the prevalence of anti-HEV IgG (5.8, 4.3, and 6.6%, respectively), anti-HEV IgM/IgA (1.9, 3.4, and 3.3%, respectively) and HEV RNA (1.3, 3.4, and 3.3%, respectively). The eleven HEV isolates obtained in the present study differed from each other by 1.7-22.8% in the ORF2 sequence and segregated into genotype 3 or 4. The occurrence rate of subclinical infection with divergent HEV strains has essentially remained unchanged during 1991-2006 in Japan.     

Serological and molecular studies on subclinical hepatitis E virus infection using periodic serum samples obtained from healthy individuals

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.     

Prevalence of hepatitis E virus infection among hemodialysis patients in Japan: evidence for infection with a genotype 3 HEV by blood transfusion

To investigate the prevalence of hepatitis E virus (HEV) infection among patients on maintenance hemodialysis, serum samples collected in January 2003 from 416 patients who had been undergoing hemodialysis for 7.6 +/- 6.3 (mean +/- standard deviation) (range, 0.3-26.0) years in a dialysis unit in Japan and serum samples that had been collected from these patients at the start of hemodialysis were tested for IgG antibodies to HEV (anti-HEV IgG) by an "in-house" enzyme-linked immunosorbent assay (ELISA). Overall, 39 patients (9.4%) had anti-HEV IgG in January 2003, and included 35 patients (8.4%) who had already been positive for anti-HEV IgG at the start of hemodialysis and 4 patients (1%) who seroconverted after initiation of hemodialysis. Periodic serum samples that had been collected from the four seroconverted patients were tested for HEV antibodies and HEV RNA. The four patients became positive for anti-HEV IgG in 1979, 1980, 1988, or 2003, and continued to be seropositive until the end of the observation period. Although anti-HEV IgM was not detectable in the four patients, three were infected transiently with apparently Japanese indigenous HEV strains of genotype 3. The patient who contracted HEV infection in 1979 had been transfused with 2 U of blood 21 days before the transient viremia: one of the two stored pilot serum samples had detectable HEV RNA with 100% identity to that recovered from the patient. Our study provides evidence of transfusion-transmitted HEV infection in Japan in 1979, and that the prevalence of de novo HEV infection during hemodialysis was low (1.1% or 4/374).     

无偿献血人群戊型肝炎病毒感染情况调查

目的调查绍兴市街头无偿献血者戊型肝炎病毒感染情况。方法3701例无偿献血者标本采用ELISA方法检测抗-HEV IgG和抗-HEV IgM,RT-PCR检测抗-HEV IgM阳性血清HEV RNA。结果本市无偿献血者抗-HEV IgG阳性率为29.91%(1107/3701);抗-HEVIgM阳性率为1.35%(50/3701);HEV RNA阳性6例,检出率为0.16%(6/3701),均为HEV基因1型;各季节抗-HEV IgG和抗-HEV IgM的阳性检出率无显著差异。结论加强对献血者感染HEV情况的检测和研究,对保证用血安全,完善安全输血的保障体系有切实的意义。     

Simultaneous detection of immunoglobulin A (IgA) and IgM antibodies against hepatitis E virus (HEV) Is highly specific for diagnosis of acute HEV infection

Serum samples collected from 68 patients (age, mean +/- the standard deviation [SD], 56.3 +/- 12.8 years) at admission who were subsequently molecularly diagnosed as having hepatitis E and from 2,781 individuals who were assumed not to have been recently infected with hepatitis E virus (HEV; negative controls; 52.9 +/- 18.9 years), were tested for immunoglobulin M (IgM) and IgA classes of antibodies to HEV (anti-HEV) by in-house solid-phase enzyme immunoassay with recombinant open reading frame 2 protein expressed in the pupae of silkworm as the antigen probe. The 68 patients with hepatitis E had both anti-HEV IgM and anti-HEV IgA. Among the 2,781 controls, 16 (0.6%) had anti-HEV IgM alone and 4 (0.1%) had anti-HEV IgA alone: these IgA/IgM anti-HEV-positive individuals were not only negative for HEV RNA but lack IgG anti-HEV antibody as well (at least in most of the cases). Periodic serum samples obtained from 15 patients with hepatitis E were tested for HEV RNA, anti-HEV IgM, and anti-HEV IgA. Although HEV RNA was detectable in the serum until 7 to 40 (21.4 +/- 9.7) days after disease onset, both IgM and IgA anti-HEV antibodies were detectable until 37, 55, or 62 days after disease onset in three patients and up through the end of the observation period (50 to 144 days) in 12 patients. These results indicate that detection of anti-HEV IgA alone or along with anti-HEV IgM is useful for serological diagnosis of hepatitis E with increased specificity and longer duration of positivity than that by RNA detection.     

Prevalence of antibodies and RNA genome of hepatitis E virus in a cohort of French immunocompromised

BackgroundRecently, cases of chronic hepatitis E have been identified in immunocompromised patients.ObjectivesTo evaluate the prevalence of anti-HEV IgG antibodies and the persistence of HEV-RNA in sera of immunocompromised patients with regular follow-up at Saint-Louis Hospital in Paris, France.Study design307 samples collected from 261 HIV-infected patients and 46 kidney transplant (KT)-patients were retrospectively tested for the presence of the following hepatitis E virus (HEV) infection markers: anti-HEV IgM antibodies, anti-HEV IgG antibodies, anti-HEV IgG avidity index, and HEV-RNA.ResultsAnti-HEV IgG positive serology was found in 4 HIV-infected patients (1.5%) and 3 KT-patients (6.5%), leading to an overall seroprevalence of 2.3%. HEV-RNA detection was not observed among 55 HIV-patients at higher risk of chronic HEV (<200 CD4 cells/mm³, elevated alanine aminotransferase (ALT) levels, and/or positive anti-HEV antibodies) and among 44 KT-patients. None of the seven patients had anti-HEV IgM antibodies, thereby excluding any acute infection. The IgG avidity index confirmed past HEV infection among tested patients.ConclusionsThe low seroprevalence observed in the Paris region does not warrant a systematic evaluation of HEV infection in immunocompromised patients. However, HEV infection must be examined as a possibility if unexplained increases in ALT should occur and after more common viral hepatitis infections are excluded.     

浙南地区无偿献血者戊型肝炎亚临床感染及病毒血症情况调查

目的 调查浙江南部地区戊型肝炎的感染情况.方法 对2008年2-10月间浙江省温州市中心血站的无偿献血者进行整群抽样,检测抗HEV IgG以及IgM抗体,并对抗HEV IgM阳性的标本进行RT-PCR检测,经测序后分析其基因型及序列同源性.结果 3044例无偿献血者中,HEVIsG阳性率为33.28%,随着年龄的升高IgG阳性率也有一定的提高,从20岁组的21.16%升高到40岁以上组的50.36%;IgM阳性率0.92%,以31～40岁年龄段感染率最高,为1.90%.通过对IgG和lgM各自阴阳性标本群的分析发现其与献血者的年龄、性别以及血型并无显著相关性.对28例HEV IgM阳性标本进行PCR检测共发现3例核酸阳性,总体阳性率约为10%,其中2例为基因4型,1例为基因1型感染.结论 浙南地区的无偿献血者中存在一定比率的HEV病毒携带者.     

浙南地区无偿献血者戊型肝炎亚临床感染及病毒血症情况调查

目的 调查浙江南部地区戊型肝炎的感染情况.方法 对2008年2-10月间浙江省温州市中心血站的无偿献血者进行整群抽样,检测抗HEV IgG以及IgM抗体,并对抗HEV IgM阳性的标本进行RT-PCR检测,经测序后分析其基因型及序列同源性.结果 3044例无偿献血者中,HEVIsG阳性率为33.28%,随着年龄的升高IgG阳性率也有一定的提高,从20岁组的21.16%升高到40岁以上组的50.36%;IgM阳性率0.92%,以31～40岁年龄段感染率最高,为1.90%.通过对IgG和lgM各自阴阳性标本群的分析发现其与献血者的年龄、性别以及血型并无显著相关性.对28例HEV IgM阳性标本进行PCR检测共发现3例核酸阳性,总体阳性率约为10%,其中2例为基因4型,1例为基因1型感染.结论 浙南地区的无偿献血者中存在一定比率的HEV病毒携带者.     

浙南地区无偿献血者戊型肝炎亚临床感染及病毒血症情况调查

目的 调查浙江南部地区戊型肝炎的感染情况.方法 对2008年2-10月间浙江省温州市中心血站的无偿献血者进行整群抽样,检测抗HEV IgG以及IgM抗体,并对抗HEV IgM阳性的标本进行RT-PCR检测,经测序后分析其基因型及序列同源性.结果 3044例无偿献血者中,HEVIsG阳性率为33.28%,随着年龄的升高IgG阳性率也有一定的提高,从20岁组的21.16%升高到40岁以上组的50.36%;IgM阳性率0.92%,以31～40岁年龄段感染率最高,为1.90%.通过对IgG和lgM各自阴阳性标本群的分析发现其与献血者的年龄、性别以及血型并无显著相关性.对28例HEV IgM阳性标本进行PCR检测共发现3例核酸阳性,总体阳性率约为10%,其中2例为基因4型,1例为基因1型感染.结论 浙南地区的无偿献血者中存在一定比率的HEV病毒携带者.     

浙南地区无偿献血者戊型肝炎亚临床感染及病毒血症情况调查

目的 调查浙江南部地区戊型肝炎的感染情况.方法 对2008年2-10月间浙江省温州市中心血站的无偿献血者进行整群抽样,检测抗HEV IgG以及IgM抗体,并对抗HEV IgM阳性的标本进行RT-PCR检测,经测序后分析其基因型及序列同源性.结果 3044例无偿献血者中,HEVIsG阳性率为33.28%,随着年龄的升高IgG阳性率也有一定的提高,从20岁组的21.16%升高到40岁以上组的50.36%;IgM阳性率0.92%,以31～40岁年龄段感染率最高,为1.90%.通过对IgG和lgM各自阴阳性标本群的分析发现其与献血者的年龄、性别以及血型并无显著相关性.对28例HEV IgM阳性标本进行PCR检测共发现3例核酸阳性,总体阳性率约为10%,其中2例为基因4型,1例为基因1型感染.结论 浙南地区的无偿献血者中存在一定比率的HEV病毒携带者.     

浙南地区无偿献血者戊型肝炎亚临床感染及病毒血症情况调查

目的 调查浙江南部地区戊型肝炎的感染情况.方法 对2008年2-10月间浙江省温州市中心血站的无偿献血者进行整群抽样,检测抗HEV IgG以及IgM抗体,并对抗HEV IgM阳性的标本进行RT-PCR检测,经测序后分析其基因型及序列同源性.结果 3044例无偿献血者中,HEVIsG阳性率为33.28%,随着年龄的升高IgG阳性率也有一定的提高,从20岁组的21.16%升高到40岁以上组的50.36%;IgM阳性率0.92%,以31～40岁年龄段感染率最高,为1.90%.通过对IgG和lgM各自阴阳性标本群的分析发现其与献血者的年龄、性别以及血型并无显著相关性.对28例HEV IgM阳性标本进行PCR检测共发现3例核酸阳性,总体阳性率约为10%,其中2例为基因4型,1例为基因1型感染.结论 浙南地区的无偿献血者中存在一定比率的HEV病毒携带者.     

浙南地区无偿献血者戊型肝炎亚临床感染及病毒血症情况调查

目的 调查浙江南部地区戊型肝炎的感染情况.方法 对2008年2-10月间浙江省温州市中心血站的无偿献血者进行整群抽样,检测抗HEV IgG以及IgM抗体,并对抗HEV IgM阳性的标本进行RT-PCR检测,经测序后分析其基因型及序列同源性.结果 3044例无偿献血者中,HEVIsG阳性率为33.28%,随着年龄的升高IgG阳性率也有一定的提高,从20岁组的21.16%升高到40岁以上组的50.36%;IgM阳性率0.92%,以31～40岁年龄段感染率最高,为1.90%.通过对IgG和lgM各自阴阳性标本群的分析发现其与献血者的年龄、性别以及血型并无显著相关性.对28例HEV IgM阳性标本进行PCR检测共发现3例核酸阳性,总体阳性率约为10%,其中2例为基因4型,1例为基因1型感染.结论 浙南地区的无偿献血者中存在一定比率的HEV病毒携带者.     

浙南地区无偿献血者戊型肝炎亚临床感染及病毒血症情况调查

目的 调查浙江南部地区戊型肝炎的感染情况.方法 对2008年2-10月间浙江省温州市中心血站的无偿献血者进行整群抽样,检测抗HEV IgG以及IgM抗体,并对抗HEV IgM阳性的标本进行RT-PCR检测,经测序后分析其基因型及序列同源性.结果 3044例无偿献血者中,HEVIsG阳性率为33.28%,随着年龄的升高IgG阳性率也有一定的提高,从20岁组的21.16%升高到40岁以上组的50.36%;IgM阳性率0.92%,以31～40岁年龄段感染率最高,为1.90%.通过对IgG和lgM各自阴阳性标本群的分析发现其与献血者的年龄、性别以及血型并无显著相关性.对28例HEV IgM阳性标本进行PCR检测共发现3例核酸阳性,总体阳性率约为10%,其中2例为基因4型,1例为基因1型感染.结论 浙南地区的无偿献血者中存在一定比率的HEV病毒携带者.     

浙南地区无偿献血者戊型肝炎亚临床感染及病毒血症情况调查

目的 调查浙江南部地区戊型肝炎的感染情况.方法 对2008年2-10月间浙江省温州市中心血站的无偿献血者进行整群抽样,检测抗HEV IgG以及IgM抗体,并对抗HEV IgM阳性的标本进行RT-PCR检测,经测序后分析其基因型及序列同源性.结果 3044例无偿献血者中,HEVIsG阳性率为33.28%,随着年龄的升高IgG阳性率也有一定的提高,从20岁组的21.16%升高到40岁以上组的50.36%;IgM阳性率0.92%,以31～40岁年龄段感染率最高,为1.90%.通过对IgG和lgM各自阴阳性标本群的分析发现其与献血者的年龄、性别以及血型并无显著相关性.对28例HEV IgM阳性标本进行PCR检测共发现3例核酸阳性,总体阳性率约为10%,其中2例为基因4型,1例为基因1型感染.结论 浙南地区的无偿献血者中存在一定比率的HEV病毒携带者.     

浙南地区无偿献血者戊型肝炎亚临床感染及病毒血症情况调查

目的 调查浙江南部地区戊型肝炎的感染情况.方法 对2008年2-10月间浙江省温州市中心血站的无偿献血者进行整群抽样,检测抗HEV IgG以及IgM抗体,并对抗HEV IgM阳性的标本进行RT-PCR检测,经测序后分析其基因型及序列同源性.结果 3044例无偿献血者中,HEVIsG阳性率为33.28%,随着年龄的升高IgG阳性率也有一定的提高,从20岁组的21.16%升高到40岁以上组的50.36%;IgM阳性率0.92%,以31～40岁年龄段感染率最高,为1.90%.通过对IgG和lgM各自阴阳性标本群的分析发现其与献血者的年龄、性别以及血型并无显著相关性.对28例HEV IgM阳性标本进行PCR检测共发现3例核酸阳性,总体阳性率约为10%,其中2例为基因4型,1例为基因1型感染.结论 浙南地区的无偿献血者中存在一定比率的HEV病毒携带者.     

High prevalence of anti-hepatitis E virus antibodies in blood donors from South West France

Cases of autochthonous acute hepatitis E occur in most industrialized countries and are frequent in the South West of France. The prevalence of anti-hepatitis E virus (HEV) IgG antibodies in blood donors in this area was determined. A total of 529 samples from rural and urban blood donors were tested. The overall prevalence was 16.6%, 19.1% of rural donors and 14.2% of urban donors had anti-HEV antibodies (P = 0.13). The antibodies were widely distributed among all age groups and the sex ratio of the anti-HEV positive blood donors was 1.12 (P = 0.57). Hunting was the only pastime or profession associated with a high prevalence of anti-HEV antibodies (P = 0.038). The frequency of anti-HEV antibodies in blood donors could reflect active autochthonous transmission in this area of France. As the risk factors for HEV infection in industrialized countries are still unknown, further studies are needed to clarify the epidemiology of HEV infection in the Midi-Pyrénées region.     

浙南地区无偿献血者戊型肝炎亚临床感染及病毒血症情况调查

目的 调查浙江南部地区戊型肝炎的感染情况.方法 对2008年2-10月间浙江省温州市中心血站的无偿献血者进行整群抽样,检测抗HEV IgG以及IgM抗体,并对抗HEV IgM阳性的标本进行RT-PCR检测,经测序后分析其基因型及序列同源性.结果 3044例无偿献血者中,HEVIsG阳性率为33.28%,随着年龄的升高IgG阳性率也有一定的提高,从20岁组的21.16%升高到40岁以上组的50.36%;IgM阳性率0.92%,以31～40岁年龄段感染率最高,为1.90%.通过对IgG和lgM各自阴阳性标本群的分析发现其与献血者的年龄、性别以及血型并无显著相关性.对28例HEV IgM阳性标本进行PCR检测共发现3例核酸阳性,总体阳性率约为10%,其中2例为基因4型,1例为基因1型感染.结论 浙南地区的无偿献血者中存在一定比率的HEV病毒携带者.     

浙南地区无偿献血者戊型肝炎亚临床感染及病毒血症情况调查

目的 调查浙江南部地区戊型肝炎的感染情况.方法 对2008年2-10月间浙江省温州市中心血站的无偿献血者进行整群抽样,检测抗HEV IgG以及IgM抗体,并对抗HEV IgM阳性的标本进行RT-PCR检测,经测序后分析其基因型及序列同源性.结果 3044例无偿献血者中,HEVIsG阳性率为33.28%,随着年龄的升高IgG阳性率也有一定的提高,从20岁组的21.16%升高到40岁以上组的50.36%;IgM阳性率0.92%,以31～40岁年龄段感染率最高,为1.90%.通过对IgG和lgM各自阴阳性标本群的分析发现其与献血者的年龄、性别以及血型并无显著相关性.对28例HEV IgM阳性标本进行PCR检测共发现3例核酸阳性,总体阳性率约为10%,其中2例为基因4型,1例为基因1型感染.结论 浙南地区的无偿献血者中存在一定比率的HEV病毒携带者.