This new developed assay presents an improvement for the detection of HCV infection, especially in the early phase of infection when antibodies are undetectable. Although less sensitive than NAT, this assay could be a suitable solution for blood screening in developing countries where NAT (or HCV core antigen-specific assay) is not affordable or its implementation is not feasible.

Background: We evaluated and analysed risk factors of HCV-infected blood donors according to HCV genotypes in order to improve the transfusion policy and safety of blood supply. Materials and Methods: HCV-RNA was analysed in sera from 518 anti-HCV-positive blood donors, who were invited to medical consultation and interview as to risk factors by means of an extensive questionnaire. HCV genotyping was done on all samples positive for HCV-RNA. Results: Of the 518 sera, 399 (77%) were HCV-RNA positive, and 394 of 399 HCV genotypes were identified. Major genotypes were 1b (34.3%), 3a (24%), 1a (19.5%) and 2 (11.4%). Of the donors, 289 (55.8%) were interviewed regarding their risk behaviour: 27% were former intravenous drug users (IVDUs), 26% had been transfused, 8% had a history of invasive diagnostic procedures, and 13% a history of surgery. Among the 224 interviewed donors, genotypes 1a and 3a were mainly associated with IVDU (51 and 45% respectively) and genotype 1b, with transfusion and nosocomial infections (40 and 25%, respectively). Conclusion: In this population of anti-HCV-positive blood donors, nosocomial infection may be a route of HCV spread, but the main risk factor remains IVDU, particularly in young men. The transfusion policy will improve if predonation interviews of such young men are done with a specific and sensitive questionnaire.

The subtype distribution of 142 genotype 2 and 97 genotype 4 hepatitis C virus (HCV) isolates from the sera of 1,319 volunteer blood donors in France was determined by gene sequencing and by phylogenetic analysis of the NS5B region and E1 envelope. Findings underlined a wide range of subtypes in both genotypes, that is, 20 in HCV-2 and 11 in HCV-4. Eighteen of these 31 subtypes had not been defined previously. Some subtypes, that is, 2a, 2b, 2c, 2i, 2k, 4a, and 4d, showed numerous strains while subtypes in donors from West Africa or Central Africa showed an endemic profile with only a few strains. A Bayesian coalescence approach was used to estimate the demographic history of each HCV subtype. The estimated mean dates of the most recent common ancestors (MRCA) were 1,889 (confidence interval (CI), 1,842-1,930) for HCV-2a, 1,886 (CI, 1,843-1,921) for HCV-2b, 1,791 (CI, 1,699-1,848) for HCV-2c, 1,846 (CI, 1,803-1,878) for HCV-2i, 1,911 (CI, 1,879-1,937) for HCV-4a, and 1,957 (CI, 1,943-1,967) for HCV-4d. The period of spread for subtype 2b, 2c, and 2i was between 1900 and 1960 whereas rapid exponential spread for subtype 2a, 4a, and 4d occurred in the 1960s. The inferred histories of population growth indicated that transmission rates differed according to HCV subtype. These results may help to predict the future burden of HCV in France.

Chagas Disease, France

In this population of anti-HCV-positive blood donors, nosocomial infection may be a route of HCV spread, but the main risk factor remains IVDU, particularly in young men. The transfusion policy will improve if predonation interviews of such young men are done with a specific and sensitive questionnaire.

Studies of blood donors positive for antibody to hepatitis C virus on enzyme-linked immunosorbent assay are probably biased by the large number of false-positive results. We evaluated the epidemiological and biological characteristics of 177 such donors with regard to the confirmatory second-generation RIBA test (Ortho Diagnostic Systems) and have compared the results to those from an age- and sex-matched control group of 177 donors negative for antibody to hepatitis C virus on enzyme-linked immunosorbent assay. Second-generation recombinant immunoblot assay was positive in 38% of cases, indeterminate in 6% and negative in 56%. The case-control study showed a significantly higher frequency of intravenous drug abuse (27% vs. 0%), blood transfusion (22% vs. 9%), history of jaundice (21% vs. 7%), elevated ALT level (49% vs. 4%) and HBc antibody positivity (32% vs. 7%) in second-generation recombinant immunoblot assay-positive donors. No such differences were found between the second-generation recombinant immunoblot assay-negative donors and their controls. The 35 second-generation recombinant immunoblot assay-positive donors without histories of transfusion or intravenous drug abuse had a significantly higher frequency of surgery with major blood loss or prolonged stays in areas of hepatitis B virus endemicity than did their controls (20% vs. 0% and 49% vs. 26%, respectively). In conclusion, at least one risk factor for HCV infection was identified in 82% of the second-generation recombinant immunoblot assay-positive donors, 91% of whom could have been identified on the basis of these risk factors, ALT level and presence of HBc antibody.

In a cohort of 483 blood donors positive for antibody to hepatitis C virus on second-generation enzyme-linked immunosorbent, the confirmatory second-generation recombinant immunoblot assay (Ortho Diagnostic Systems) was positive in 172 cases (36%), indeterminate in 113 (23%), and negative in 198 (41%). We further studied 94 of the donors (recombinant immunoblot assay positive in 85, indeterminate in 6, and negative in 3). Alanine transaminase (ALT) activity, assayed on three occasions, was elevated in at least one assay in 85% of the 85 recombinant immunoblot assay-positive donors. Liver disease was present in 95% of these patients (chronic persistent hepatitis, 35%; chronic active hepatitis, 53%; cirrhosis, 7%). Ten of the 13 recombinant immunoblot assay-positive donors with normal ALT activity had liver disease; polymerase chain reaction testing for viral RNA was predictive of liver disease in most cases. Donors with cirrhosis differed significantly from cirrhosis-free donors in terms of age, sex ratio, ALT activity, and excessive alcohol consumption. Three of the 6 recombinant immunoblot assay-indeterminate donors (isolated C 22) who underwent histological examination had elevated ALT activity and liver disease. The 3 recombinant immunoblot assay-negative donors evaluated were free of liver disease. This study shows that anti-HCV second-generation enzyme-linked immunosorbent positivity is confirmed in fewer than 40% of blood donors by the second-generation recombinant immunoblot assay, and that liver disease is present in 95% of recombinant immunoblot assay-positive donors. Recombinant immunoblot assay positivity combined with viremia is frequently associated with the existence of liver disease, regardless of transaminase activity. Excessive alcohol consumption may be an important factor in the onset of cirrhosis in anti-HCV-positive blood donors.

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