National survey of hepatitis B virus (HBV) polymorphism in asymptomatic HBV blood donors from 1999 to 2007 in France.

BACKGROUND: Hepatitis B virus (HBV) diversity is characterized by eight genotypes correlated to eight hepatitis B surface antigen (HBsAg) subtypes, which differ in their geographical distribution. STUDY DESIGN AND METHODS: To establish virologic characteristics and the evolution of HBV diversity, we carried out a study over a 9-year period in HBV-infected French blood donors. HBsAg subtyping based on specific antibody method concerned 2901 donors, from whom 940 have been analyzed by an S-gene sequencing to determine genotypes and S-gene mutations. RESULTS: HBsAg subtypes were distributed as follows: ayw2, 34.4%; adw2, 25.7%; ayw1, 10.2%; ayw4, 14.9%; adr, 7.8%; ayw3, 6.4%; and adw4, 0.7%. Ayw4 (Genotype E) proportion increased over time in correlation with an increased proportion of subjects originated from sub-Saharan Africa. The genotype observed with the highest proportion was D (43.0%), then A (26.2%), E (17.5%), B (6.5%), C (6.4%), and F (0.4%). Genotype B had the highest proportion of hepatitis B e antigen (39.2%) and the highest viral loads (VLs). Forty-three (5.5%) isolates presented one (n=35) or multiple (n=8) amino acid envelope substitutions. Donors infected with mutated isolates had lowest VLs. rtA181T/sW172 stop mutation associated with resistance to nucleos(t)ide analogs was detected in two donors suggesting a transmission of these isolates. CONCLUSION: This extensive study shows that HBV genotype evolution is closely linked to the geographical origin of subjects and that the occurrence of viral envelope mutants is not an exceptional event in healthy HBV chronic carriers. Blood donors rarely recruited in HBV studies provide further relevant information on the characteristics of HBV diversity.

Testing blood donors for Chagas disease in the Paris area, France: first results after 18 months of screening.

BACKGROUND: Chagas disease is endemic in Latin America (LA). Currently 10 million people are infected despite World Health Organization efforts aimed at preventing domestic transmission. However, with the migration of infected asymptomatic individuals to nonendemic countries, transmission of Chagas disease by transfusion may become a worldwide problem. The observation that the number of cases of Chagas disease has increased over the past 10 years in French Guiana, together with the results of a previous hospital-based study in the Paris area, confirms the transmission of Chagas disease from patients coming from LA. For these reasons, the French authorities stopped the collection of blood in French Guiana in 2005 and began screening blood donors in the French Caribbean islands and, in 2007, in continental France. STUDY DESIGN AND METHODS: Data on birth place, mother's birth place, and travel in LA were recorded for at-risk donors. These subjects were tested using two enzyme-linked immunosorbent assays (ELISAs). RESULTS: Of the 312,458 individuals who gave blood in the Paris area during an 18-month period, 30,837 were tested. Of these, 972 were born in LA, three of whom were positive for the two ELISAs and immunofluorescence tests. The prevalence of Trypanosoma cruzi-positive donors was 9.7 in 100,000 tested donors, but 0.31% among donors born in LA. Serology tests gave discrepant results in 1.02% of the samples. CONCLUSION: The efficiency of blood donor screening programs could be improved by screening only blood donors who were born in LA or who have traveled in LA for extended periods, using a single enzyme immunoassay.

A revised method for estimating hepatitis B virus transfusion residual risk based on antibody to hepatitis B core antigen incident cases.

BACKGROUND: To take into account the transient nature of hepatitis B virus (HBV) antigenemia, the calculation of HBV residual risk (RR), based on the incidence/window period model, is adjusted by a correction factor that adds uncertainty to the RR estimates. STUDY DESIGN AND METHODS: This new method to estimate the RR for HBV is a weighted sum of the RR derived from hepatitis B surface antigen (HBsAg) incident cases and the one derived from antibody hepatitis B core antigen (HBc) incident cases. An anti-HBc incident case was defined as a donation from a blood donor who had made at least one anti-HBc-negative donation followed by a donation that was found positive with two different assays within a 3-year period and positive for at least one of the following markers: 1) antibody to hepatitis B e antigen or hepatitis B e antigen, 2) anti-HBc immunoglobulin M, 3) HBV DNA, 4) hepatitis B surface antibody without HBV vaccination history, or 5) HBV DNA retrospectively found in the previous donation. Five overlapping 3-year study periods between 2000 and 2006 were analyzed. RESULTS: The HBV RR estimated with the classical method ranged from 1.51 (2000-2002) to 0.69 per million donations in 2004 through 2006 with a decrease in 2002 through 2004 due to only two HBsAg incident cases reported in this period. By applying the revised model, the HBV RR ranged from 1.06 (2000-2002) to 0.49 per million donations (2004-2006), with a regular decrease. CONCLUSION: The new presented model provides HBV RR estimates that do not statistically differ from those obtained with the classical model; however, it provides more accurate data, especially in low endemic areas where the HBsAg incidence is low.