Demographic history of HIV-1 subtypes B and F in Brazil.
The reconstruction of the epidemic history of several HIV populations, by using methods that infer the population history from sampled gene sequence data, has revealed important subtype-specific and regional-specific differences in patterns of epidemic growth. Here, we employ Bayesian coalescent-based methods to compare the population history of the HIV-1 subtype B and F1 epidemics in Brazil from non-contemporary env and pol gene sequences. Our results suggest that after the introduction of the subtypes B and F1 into Brazilian population, around mid to late 1960s and late 1970s, respectively, these subtypes experienced an initial period of exponential growth with similar epidemic growth rates ( approximately 0.5-0.6year(-1)). Later, the spreading rate of both subtypes seems to have slowed-down since mid to late 1980s. This demographic pattern is very similar to that reported for the subtype B epidemics in high-income countries where HIV was initially transmitted through homosexual intercourse and injecting drug use, as in Brazil; suggesting that the characteristics of transmission networks may be a key determinant of the HIV epidemic growth pattern. It is important to note that most of the subtype B and F1 sequences used in this study come from the Southeast region that has been the most affected by the AIDS epidemic in Brazil, being responsible for around 63% of all AIDS cases reported since the early eighties; but may not represent the demographic trend of the HIV-1 epidemic in other Brazilian regions.
Bello
Gonzalo
G
Laboratory of AIDS and Molecular Immunology, Department of Immunology, Oswaldo Cruz Institute - FIOCRUZ, Av. Brasil 4365, 21045-900 Rio de Janeiro, RJ, Brazil. gbello@ioc.fiocruz.br
Eyer-Silva
Walter A
WA
Couto-Fernandez
José C
JC
Guimarães
Monick L
ML
Chequer-Fernandez
Saada L
SL
Teixeira
Sylvia L M
SL
Morgado
Mariza G
MG
D001499:Bayes Theorem; D001938:Brazil / Q000453:epidemiology; D019143:Evolution, Molecular; D015752:Genes, env; D015751:Genes, pol; D015658:HIV Infections / Q000453:epidemiology* / Q000821:virology*; D015497:HIV-1 / Q000145:classification* / Q000235:genetics*; D006801:Humans; D010802:Phylogeny; D013997:Time Factors