title: Molecular epidemiology of HIV-1 transmission in a cohort of HIV-1 concordant heterosexual couples from Dakar, Senegal.
abstract: BACKGROUND
  A large number of HIV-1 infections in Africa occur in married couples. The predominant direction of intracouple transmission and the principal external origins of infection remain important issues of debate.
  
  
  METHODS
  We investigated HIV-1 transmission in 46 HIV-1 concordant positive couples from Dakar, Senegal. Intracouple transmission was confirmed by maximum-likelihood phylogenetic analysis and pairwise distance comparisons of HIV-1 env gp41 sequences from both partners. Standardized interview data were used to deduce the direction as well as the external sources of the intracouple transmissions.
  
  
  RESULTS
  Conservative molecular analyses showed linked viruses in 34 (74%) couples, unlinked viruses in 6 (13%) couples, and indeterminate results for 6 (13%) couples. The interview data corresponded completely with the molecular analyses: all linked couples reported internal transmission and all unlinked couples reported external sources of infection. The majority of linked couples (93%) reported the husband as internal source of infection. These husbands most frequently (82%) reported an occasional sexual relationship as external source of infection. Pairwise comparisons of the CD4 count, antiretroviral therapy status, and the proportion of gp41 ambiguous base pairs within transmission pairs correlated with the reported order of infection events.
  
  
  CONCLUSIONS
  In this suburban Senegalese population, a majority of HIV-1 concordant couples showed linked HIV-1 transmission with the husband as likely index partner. Our data emphasize the risk of married women for acquiring HIV-1 as a result of the occasional sexual relationships of their husbands.
authors.affiliation: Laboratory of Immunology, Department of Biomedical Sciences, Institute of Tropical Medicine, Antwerp, Belgium. wjennes@itg.be
authors.forename: Wim
authors.initials: W
authors.lastname: Jennes
authors.forename: Jordan K
authors.initials: JK
authors.lastname: Kyongo
authors.forename: Evelyn
authors.initials: E
authors.lastname: Vanhommerig
authors.forename: Makhtar
authors.initials: M
authors.lastname: Camara
authors.forename: Sandra
authors.initials: S
authors.lastname: Coppens
authors.forename: Moussa
authors.initials: M
authors.lastname: Seydi
authors.forename: Souleymane
authors.initials: S
authors.lastname: Mboup
authors.forename: Leo
authors.initials: L
authors.lastname: Heyndrickx
authors.forename: Luc
authors.initials: L
authors.lastname: Kestens
mesh_terms: D015331:Cohort Studies; D005260:Female; D015658:HIV Infections / Q000453:epidemiology* / Q000635:transmission*; D006679:HIV Seropositivity; D015497:HIV-1 / Q000235:genetics*; D020010:Heterosexuality; D006801:Humans; D008297:Male; D017720:Molecular Epidemiology; D012675:Senegal; D012747:Sexual Partners; D018454:Spouses