Spatiotemporal dynamics of the HIV-1 CRF06_cpx epidemic in Western Africa.
OBJECTIVE
To investigate the origin and spatiotemporal dynamics of dissemination of the HIV-1 CRF06_cpx clade in western Africa.


METHODS
A total of 180 HIV-1 CRF06_cpx-like pol sequences isolated from 12 different countries from west and west-central Africa over a period of 16 years (1995-2010) were analyzed.


METHODS
Evolutionary, phylogeographic and demographic parameters were jointly estimated from sequence data using a Bayesian coalescent-based method and combined with molecular epidemiology and spatial accessibility data.


RESULTS
The CRF06_cpx most probably emerged in Burkina Faso in 1979 (1970-1985). From Burkina Faso, the virus was first disseminated to Mali and Nigeria during the 1980s and later to other countries from west and west-central Africa. Demographic reconstruction indicates that the CRF06_cpx epidemic grew exponentially during the 1980s, with a median growth rate of 0.82 year (0.60-1.09 year), and after stabilize. We found a negative correlation between CRF06_cpx prevalence and the geographical distance to Burkina Faso's capital. Regional accessibility information agrees with the overall geographical range of the CRF06_cpx, but not fully explains the highly heterogeneous distribution pattern of this CRF at regional level.


CONCLUSIONS
The CRF06_cpx epidemic in western Africa probably emerged at the late 1970s and grew during the 1980s at a rate comparable to the HIV-1 epidemics in the United States and Europe. Burkina Faso seems to be the most important epicenter of dissemination of the HIV-1 CRF06_cpx strain at regional level. The explanation for the current geographical distribution of CRF06_cpx is probably multifactorial.
Laboratório de AIDS e Imunologia Molecular, Instituto Oswaldo Cruz, FIOCRUZ, 21045-900 Rio de Janeiro, RJ, Brazil.
Edson
E
Delatorre
Gonzalo
G
Bello
D000354:Africa, Western / Q000453:epidemiology; D001499:Bayes Theorem; D058872:Epidemics; D015658:HIV Infections / Q000453:epidemiology* / Q000235:genetics / Q000635:transmission; D015497:HIV-1 / Q000145:classification* / Q000235:genetics / Q000302:isolation & purification; D006801:Humans; D017720:Molecular Epidemiology; D010802:Phylogeny