title: Occult hepatitis B virus infection among blood donors in Colombia.
abstract: BACKGROUND
  Hepatitis B virus (HBV) surface antigen (HBsAg) screening in blood banks reduced the risk of HBV transmission through transfusion. However, the detection of occult HBV infection among blood donors is imperative for improving blood safety. The aim of this study was to determine the frequency of occult hepatitis B virus infection among blood donors in Medellin, North West Colombia and to characterize the viral genotypes and mutations.
  
  
  METHODS
  Serum samples from blood donors with the serological profile HBsAg-/Anti-HBc+ were evaluated by nested or hemi-nested PCR for HBV genome ORF C, ORF S and ORF X. A pairwise analysis was carried out with deduced amino acids sequence of overlapping S/P region.
  
  
  RESULTS
  A total of 302 serum samples HBsAg-/Anti-HBc+ from donors recruited in a blood bank in Medellin were evaluated by PCR for the HBV genome. Six samples (1.98%) were identified as occult HBV infection. The cases were confirmed by sequencing and viral load analysis. All HBV strains were genotype F, subgenotype F3. The amino acid substitutions sY100H, sV184A, and sK141N were detected in ORF S and rtL108P, rtR110G, rtL180M, rtR192C, rtT150S, and rtL187V in ORF P.
  
  
  CONCLUSIONS
  This is the first report and characterization of OBI cases in blood donors in Colombia. Six from 302 donors HBsAg-/Anti-HBc+ were identified. The mutations rtL108P, rtR110G, rtR192C, rtT150S and rtI187V were characterized for the first time in these samples. Further studies are necessary to explore if these mutations could potentially impair HBsAg production.
authors.forename: Wilson Alfredo
authors.initials: WA
authors.lastname: Rios-Ocampo
authors.forename: Fabián
authors.initials: F
authors.lastname: Cortes-Mancera
authors.forename: Juan Camilo
authors.initials: JC
authors.lastname: Olarte
authors.forename: Angela
authors.initials: A
authors.lastname: Soto
authors.affiliation: Grupo de Gastrohepatologia, Facultad de Medicina, Universidad de Antioquia, UdeA, Calle 70 No, 52-21, Medellín, Colombia. maria.navas@udea.edu.co.
authors.forename: Maria-Cristina
authors.initials: MC
authors.lastname: Navas
mesh_terms: D000328:Adult; D000595:Amino Acid Sequence; D001771:Blood Banks / Q000706:statistics & numerical data; D001782:Blood Donors / Q000706:statistics & numerical data; D003105:Colombia / Q000453:epidemiology; D005838:Genotype; D006510:Hepatitis B Antibodies / Q000097:blood / Q000276:immunology; D006514:Hepatitis B Surface Antigens / Q000097:blood / Q000737:chemistry / Q000235:genetics; D006515:Hepatitis B virus / Q000145:classification / Q000235:genetics / Q000276:immunology / Q000302:isolation & purification*; D006526:Hepatitis C / Q000097:blood* / Q000453:epidemiology / Q000821:virology; D006801:Humans; D008297:Male; D008875:Middle Aged; D008969:Molecular Sequence Data; D010802:Phylogeny; D016133:Polymerase Chain Reaction; D016415:Sequence Alignment; D055815:Young Adult
chemical_list: D006510:Hepatitis B Antibodies; D006514:Hepatitis B Surface Antigens