title: Twenty years of prospective molecular epidemiology in Senegal: changes in HIV diversity.
abstract: Over a 20-year period we have observed the dynamics of HIV-1 subtypes and HIV-2 infection in a prospective cohort of registered female sex workers (FSW) in Dakar, Senegal. Prevalence and incidence rates for HIV-1 and HIV-2 are described from 290 seroprevalent and 193 seroincident subjects who were among the 3,910 women enrolled between 1985 and 2004. We report a significant decrease of HIV-2 prevalence in the cohort, parallel to the introduction and rise of HIV-1 infection. In 328 HIV-1-infected women, a 385-bp C2-V3 fragment of the envelope gene was sequenced and classified into the following subtypes or recombinant forms: 239 (72%) were subtype A [of which 180 (55%) were CRF02_AG and 53 (16%) were A3], 10 (3%) were B, 12 (4%) were C, 11 (4%) were D, 18 (6%) were G, 24 (7%) were CRF06_cpx, and 7 (2%) were CRF09_cpx. We found an increasing proportion of CRF02_AG over many years, but recently subsubtype A3 has over-taken CRF02_AG, with the largest proportion of new infections. The predominance of existing HIV-1 subtypes did not preclude the emergence and increase of other closely related subtypes or recombinant forms. This 20-year prospective serological and sequence analysis of HIV viruses reveals a complex and changing HIV epidemic in Senegal.
authors.affiliation: Department of Immunology and Infectious Disease, Harvard School of Public Health, Boston, Massachusetts 02115, USA.
authors.forename: Donald J
authors.initials: DJ
authors.lastname: Hamel
authors.forename: Jean-Louis
authors.initials: JL
authors.lastname: Sankalé
authors.forename: Geoffrey
authors.initials: G
authors.lastname: Eisen
authors.forename: Seema Thakore
authors.initials: ST
authors.lastname: Meloni
authors.forename: Christopher
authors.initials: C
authors.lastname: Mullins
authors.forename: Aissatou
authors.initials: A
authors.lastname: Gueye-Ndiaye
authors.forename: Souleymane
authors.initials: S
authors.lastname: Mboup
authors.forename: Phyllis J
authors.initials: PJ
authors.lastname: Kanki
mesh_terms: D015331:Cohort Studies; D005260:Female; D015658:HIV Infections / Q000453:epidemiology* / Q000821:virology; D015497:HIV-1 / Q000145:classification / Q000235:genetics / Q000302:isolation & purification; D015498:HIV-2 / Q000302:isolation & purification; D006801:Humans; D015994:Incidence; D008137:Longitudinal Studies; D017720:Molecular Epidemiology; D008969:Molecular Sequence Data; D010802:Phylogeny; D011159:Population Surveillance; D015995:Prevalence; D012675:Senegal / Q000453:epidemiology; D011477:Sex Work