Yuhko Gotanda

Polyphyletic strains of hepatitis E virus are responsible for sporadic cases of acute hepatitis in Japan.

ABSTRACT Among 87 patients who were previously treated for acute hepatitis of unknown etiology between 1992 and 2001 at five hospitals in Japan, 11 (13%) patients were positive for immunoglobulin M-class antibodies to hepatitis E virus (HEV) by enzyme immunoassay and had detectable HEV RNA by reverse transcription-PCR with two independent sets of primers derived from well-conserved genomic areas in open reading frames 1 and 2. Clinical HEV infection was significantly associated with male sex (9 of 11 versus 29 of 76 patients [P < 0.01]) and older age (52 ± 11 [mean ± standard deviation] versus 41 ± 17 years [P < 0.05]), and its prevalence differed by geographic region (6 to 25%), with a higher rate in the northern part of Japan. At admission, the 11 patients with HEV-associated hepatitis had elevated alanine aminotransferase levels of 914 to 4,850 IU/liter, and all but 1 had elevated bilirubin levels of 1.5 to 24.0 mg/dl. The 11 HEV isolates were of genotype III or IV and were segregated into three groups with intergroup nucleotide differences of 9.5 to 22.0%. Phylogenetic analysis revealed that four isolates of genotype III were closely related to a Japanese isolate, while the other four isolates of the same genotype were nearest those from the United States. The remaining three isolates were close to known isolates of genotype IV in China and Taiwan but shared less than 88% identity with them. These results indicate that multiple genotypes of HEV cocirculate in Japan and contribute to the development of sporadic acute hepatitis, with the prevalence differing by age, sex, and geographic region.

High Prevalence of Antibodies to Hepatitis A and E Viruses and Viremia of Hepatitis B, C, and D Viruses among Apparently Healthy Populations in Mongolia

ABSTRACT The prevalence of infection with hepatitis A virus (HAV), HBV, HCV, HDV, and HEV was evaluated in 249 apparently healthy individuals, including 122 inhabitants in Ulaanbaatar, the capital city of Mongolia, and 127 age- and sex-matched members of nomadic tribes who lived around the capital city. Overall, hepatitis B surface antigen (HBsAg) was detected in 24 subjects (10%), of whom 22 (92%) had detectable HBV DNA. Surprisingly, HDV RNA was detectable in 20 (83%) of the 24 HBsAg-positive subjects. HCV-associated antibodies were detected in 41 (16%) and HCV RNA was detected in 36 (14%) subjects, none of whom was coinfected with HBV, indicating that HBV/HCV carriers account for one-fourth of this population. Antibodies to HAV and HEV were detected in 249 (100%) and 28 (11%) subjects, respectively. Of 22 HBV DNA-positive subjects, genotype D was detected in 21 subjects and genotype F was detected in 1 subject. All 20 HDV isolates recovered from HDV RNA-positive subjects segregated into genotype I, but these differed by 2.1 to 11.4% from each other in the 522- to 526-nucleotide sequence. Of 36 HCV RNA-positive samples, 35 (97%) were genotype 1b and 1 was genotype 2a. Reflecting an extremely high prevalence of hepatitis virus infections, there were no appreciable differences in the prevalence of hepatitis virus markers between the two studied populations with distinct living place and lifestyle. A nationwide epidemiological survey of hepatitis viruses should be conducted in an effort to prevent de novo infection with hepatitis viruses in Mongolia.

Hepatitis B NAT virus‐positive blood donors in the early and late stages of HBV infection: analyses of the window period and kinetics of HBV DNA

Background and Objectives  The Japanese Red Cross (JRC) carries out nucleic acid amplification testing (NAT) for hepatitis B virus (HBV), hepatitis C virus (HCV) and human immunodeficiency virus‐1 (HIV‐1) by using a multiplex (MPX) reagent. Screening is undertaken on serologically negative units. In this study we characterized HBV NAT‐positive donations individually and analysed the window period and kinetics of HBV DNA, during acute infection, in follow‐up studies.

A new method of concentrating hepatitis B virus (HBV) DNA and HBV surface antigen: an application of the method to the detection of occult HBV infection

Background  The risk of post‐transfusion hepatitis B virus (HBV) infection has been reduced after the implementation of HBV nucleic acid amplification technology (NAT). However, the problem of HBV DNA‐positive and HBV surface antigen (HBsAg)‐negative occult HBV infections remains to be solved. This is in part due to the HBV DNA load being too low to detect these occult HBV infections using mini‐pool NAT. In Japan, the assay for the antibody against the HBV core antigen (anti‐HBc) has not completely excluded occult HBV infection. To solve this problem, we have developed a new method of concentrating HBV DNA and HBsAg simultaneously to increase the sensitivity of detection tests.