title: Phylogeography, risk factors and genetic history of hepatitis C virus in Gabon, central Africa.
abstract: BACKGROUND
  The epidemiological and molecular characteristics of hepatitis C virus (HCV) infection in the general population have been poorly investigated in Africa. The aim of this study was to determine the prevalence, genotype distribution and epidemic history of HCV in the Gabonese general population.
  
  
  RESULTS
  A total of 4042 sera collected from adults in 220 villages in all nine administrative areas of the country were screened for antibodies to HCV. HCV NS5B region sequencing was performed for molecular characterization and population genetic analyses. Of 4042 tested sera, 455 (11.2%) were positive. The seroprevalence of HCV varied significantly by administrative area, with the highest rate in Ogooué-Lolo province (20.4%) and the lowest in Ogooué-Maritine province (3.7%). History of parenteral injections, past hospital admission and age over 55 years were independent risk factors for HCV infection (p<0.0001). Phylogenetic analyses showed that 91.9% of the strains were genotype 4 (HCV-4), 5.7% genotype 1 and 2.2% genotype 2. HCV-4 strains were highly heterogeneous, with more than eight subtypes; subtype 4e predominated (57.3%). Coalescence analyses indicated that subtype 4e was the oldest, with an estimated most recent common ancestor of 1702 [95% CI, 1418-1884]. The epidemic profile indicated that it spread exponentially during the first part of the 20th century, probably by iatrogenic transmission.
  
  
  CONCLUSIONS
  These results confirm the endemicity of HCV subtype 4e in Gabon and show that its spread is due to a cohort effect, with previous, possibly iatrogenic events. More extensive epidemiological studies are needed to better characterize the route of transmission and the dissemination of HCV in Gabon.
authors.affiliation: Centre International de Recherches Médicales de Franceville, Franceville, Gabon.
authors.forename: Richard
authors.initials: R
authors.lastname: Njouom
authors.forename: Mélanie
authors.initials: M
authors.lastname: Caron
authors.forename: Guillaume
authors.initials: G
authors.lastname: Besson
authors.forename: Guy-Roger
authors.initials: GR
authors.lastname: Ndong-Atome
authors.forename: Maria
authors.initials: M
authors.lastname: Makuwa
authors.forename: Régis
authors.initials: R
authors.lastname: Pouillot
authors.forename: Dieudonné
authors.initials: D
authors.lastname: Nkoghé
authors.forename: Eric
authors.initials: E
authors.lastname: Leroy
authors.forename: Mirdad
authors.initials: M
authors.lastname: Kazanji
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D005681:Gabon / Q000453:epidemiology; D016174:Hepacivirus / Q000235:genetics* / Q000472:pathogenicity; D006526:Hepatitis C / Q000453:epidemiology / Q000235:genetics* / Q000635:transmission; D006801:Humans; D008297:Male; D008875:Middle Aged; D010802:Phylogeny; D058974:Phylogeography; D012307:Risk Factors; D017423:Sequence Analysis, RNA; D017361:Viral Nonstructural Proteins / Q000235:genetics*; D012324:RNA-Dependent RNA Polymerase
chemical_list: D017361:Viral Nonstructural Proteins; C087036:NS-5 protein, hepatitis C virus; D012324:RNA-Dependent RNA Polymerase