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Publication Details
AFRICAN RESEARCH NEXUS
SHINING A SPOTLIGHT ON AFRICAN RESEARCH
medicine
Characterization of occult hepatitis B virus strains in South African blood donors
Hepatology, Volume 49, No. 6, Year 2009
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Description
Since October 2005, all blood units collected in South Africa were screened individually for human immunodeficiency virus (HIV)-1, hepatitis B and C virus (HBV, HCV) genomes uncovering preseroconversion window period (WP) infections for each virus and occult HBV infections (OBIs) defined as persistent HBV DNA without detectable hepatitis B surface antigen (HBsAg). Samples identified as HBsAg-negative/ DNA-positive were confirmed by combining real-time quantitative polymerase chain reaction, nested amplification, anti-HBc and anti-HBs. Amplified basic core promoter/precore, pre-S/S, and whole genome were sequenced, analyzed, and compared to 73 HBsAg+strains. Genotype was determined by phylogenetic analysis. From 109 samples examined, 54 were classified as OBI, 14 as WP, 20 as false-positive, five as other classification, and 16 as undetermined due to lack of serological or follow-up data. OBI donors were predominantly males (67%), median age 31 years, black (54%), with normal alanine aminotransferase levels. Viral load ranged between unquantifiable and 518 IU/mL (median 5 IU/mL). Genotype A1 was more frequent (23 strains) than genotypeD(seven strains). Genotype A1 strains were little mutated. In the major hydrophilic region, 56.5% strains were wild type or with few amino acid substitutions. Most important, all 13 full genome sequences presented 1 to 7 mutations known to or assumed to negatively impact viral replication. In particular, 6/13 sequences had a stop codon in the HBx gene translated into deletion of 117 or 19-25 C-terminus amino acids not found in 15 HBeAg+ HBsAg+ strains. One WP sequence with an HBx stop codon suggested infectivity. Conclusion: Genotype A1 OBIs are different from genotype A2 and DOBIs in that there is little evidence of immune pressure as a major factor involved in OBI genesis. Limited replication appears mostly related to genetic viral defects. Copyright © 2009 by the American Association for the Study of Liver Diseases.
Authors & Co-Authors
Allain, Jean Pierre
United Kingdom, Cambridge
University of Cambridge
United Kingdom, Cambridge
Cambridge Blood Centre
Belkhiri, Dalila
United Kingdom, Cambridge
University of Cambridge
Vermeulen, Marion
South Africa, Weltevreden Park
South African National Blood Service
Crookes, Robert L.
South Africa, Weltevreden Park
South African National Blood Service
Cable, Russell T.
South Africa, Cape Town
Western Province Blood Transfusion Service
Amiri, Azin
United Kingdom, Cambridge
University of Cambridge
Reddy, Ravi
South Africa, Weltevreden Park
South African National Blood Service
Bird, Arthur Richard
South Africa, Cape Town
Western Province Blood Transfusion Service
Candotti, Daniel
United Kingdom, Bristol
Nhs Blood and Transplant
Statistics
Citations: 83
Authors: 9
Affiliations: 5
Identifiers
Doi:
10.1002/hep.22879
ISSN:
02709139
Research Areas
Genetics And Genomics
Infectious Diseases
Study Design
Cohort Study
Study Approach
Quantitative
Study Locations
South Africa