Interferon alone or combined with ribavirin for acute prolonged infection with hepatitis C virus in chimpanzees.

Infection with hepatitis C virus (HCV) persisted for longer than 29 weeks in 2 chimpanzees after they had been inoculated with it experimentally. One of them (C-210) received short-term subcutaneous interferon-α (IFN-α) 6 million units (MU) daily for 7 days at week 29. He cleared HCV RNA from the serum and remained negative for it during 25 weeks after the withdrawal of IFN.

Age- and gender-specific distributions of hepatitis B virus (HBV) genotypes in Japanese HBV-positive blood donors.

Background: There are an increasing number of reports on the hepatitis B virus (HBV) genotype distribution in acute or chronic HBV-infected patients in Japan; however, reports on the HBV genotype of blood donors are few. To compare the HBV genotypes of hepatitis B surface antigen (HBsAg)-positive blood donors with infected patients, all the HBsAg-positive donors' genotypes were determined.

Study Design And Methods: Data on Japanese blood donors from October 2006 to September 2007 were obtained from the Japanese Red Cross database.

Titration of hepatitis B virus infectivity in the sera of pre-acute and late acute phases of HBV infection: transmission experiments to chimeric mice with human liver repopulated hepatocytes.

Studies of hepatitis B virus (HBV) infection in non-human primates such as chimpanzees are no longer possible due to ethical considerations and the endangered status of chimpanzees since April 2007 in Japan. A human hepatocyte transplanted chimeric mouse was used to characterize HBV infectivity in serial stages of acute infection. Chimeric mice were inoculated intravenously with serum samples obtained from an experimentally infected chimpanzee with HBV.

Minimum infectious dose of hepatitis B virus in chimpanzees and difference in the dynamics of viremia between genotype A and genotype C.

Background: In planning optimal hepatitis B virus (HBV) blood screening strategies, the minimum infectious dose and early dynamics of HBV need to be determined for defining the window period for HBV DNA as well as for hepatitis B surface antigen (HBsAg).

Study Design And Methods: Pairs of chimpanzees were inoculated with preacute-phase inocula containing HBV of genotype A or genotype C to determine the minimum infectious dose, and two pairs of chimps infected with the lowest infectious dose of genotypes A and C were followed for HBV markers.

Results: The minimum 50 percent chimpanzee infectious dose (CID50) was estimated to be approximately 10 copies for genotype A and for genotype C.

Infectivity of blood components with low hepatitis B virus DNA levels identified in a lookback program.

Background: Japanese Red Cross (JRC) blood centers implemented anti-hepatitis B core antigen (HBc) screening in 1989 and 50-minipool (MP)-nucleic acid testing (NAT) in 2000. A systematic lookback study has been conducted to determine the hepatitis B virus (HBV) transmission risk of donations drawn in the pre-hepatitis B surface antigen (HBsAg) and/or MP-NAT window phase and by donors with occult HBV infection.

Study Design And Methods: JRC blood centers have been storing aliquots of every blood donation since 1996.

Early dynamics of hepatitis C virus in the circulation of chimpanzees with experimental infection.

Two chimpanzees were inoculated with hepatitis C virus (HCV) and followed on a daily basis for 12 days. HCV RNA became detectable in their sera on day 5 by polymerase chain reaction with the detection limit of 10(2) copies/ml. Based on an exponential growth observed until 8 or 9 days after inoculation in their sera, the doubling time of HCV in the circulation was estimated at 6.

Titration of hepatitis C virus in chimpanzees for determining the copy number required for transmission.

Objective: To determine the copy number of hepatitis C virus (HCV) RNA, determined by nucleic acid amplification test (NAT) for screening blood units in Japan, that can transmit infection to chimpanzees.

Methods: Fresh-frozen plasma with markers of HCV infection, as well as inocula pedigreed from 1 of them, were evaluated for the infectious activity in chimpanzees.

Results: One unit each (273-282 ml) of fresh-frozen plasma from 2 blood donors or a pool from 13 donors to make a unit, which contained high-titered antibody to HCV but without HCV RNA detectable by NAT, did not infect any of 3 chimpanzees.