title: Phylodynamics of major HIV-1 subtype B pandemic clades circulating in Latin America.
abstract: OBJECTIVE
  To obtain a comprehensive description of the evolutionary and demographic history of major HIV-1 subtype B pandemic (BPANDEMIC) clades circulating in Latin America.
  
  
  METHODS
  A total of 6789 HIV-1 subtype B pol sequences collected from seven different Latin American countries between 1990 and 2011 were combined with BPANDEMIC reference sequences (n = 500) from the United States and France.
  
  
  METHODS
  Major BPANDEMIC clades were identified by maximum likelihood phylogenetic analysis with sequential pruning of ambiguously positioned taxa. Time scale and demographic reconstructions were performed using a Bayesian coalescent-based method.
  
  
  RESULTS
  We identified 12 major BPANDEMIC monophyletic lineages mainly composed by Latin American sequences and that together comprise 36% of all subtype B sequences from the region here included. Four clades belong to two major regional lineages that comprise sequences from at least two neighboring countries, whereas the other eight clades were country-specific. The median age of major Latin American BPANDEMIC clades encompass a period of two decades (1968-1988), although most of them probably arose before the early 1980s. All major clades seem to have experienced an initial period of exponential growth, with median epidemic growth rates that range from 0.50 yearto 0.94 year, followed by a recent decline in growth rate.
  
  
  CONCLUSIONS
  About one-third of HIV-1 subtype B infections in Latin America originated from the spread of a few BPANDEMIC founder strains probably introduced in the region since the late 1960s. Despite their initial successful dissemination, all major BPANDEMIC clades showed signs of subsequent epidemic stabilization.
authors.affiliation: aLaboratório de AIDS e Imunologia Molecular, Instituto Oswaldo Cruz, FIOCRUZ, Rio de Janeiro, Brazil bLaboratorio de Organizacion y Evolucion del Genoma, Departamento de Ecología y Evolucion, Facultad de Ciencias-CURE, Universidad de la Republica, Montevideo, Uruguay.
authors.forename: Daiana
authors.initials: D
authors.lastname: Mir
authors.forename: Marina
authors.initials: M
authors.lastname: Cabello
authors.forename: Hector
authors.initials: H
authors.lastname: Romero
authors.forename: Gonzalo
authors.initials: G
authors.lastname: Bello
mesh_terms: D005838:Genotype; D015658:HIV Infections / Q000453:epidemiology* / Q000821:virology*; D015497:HIV-1 / Q000145:classification* / Q000235:genetics* / Q000302:isolation & purification; D006801:Humans; D007843:Latin America / Q000453:epidemiology; D017720:Molecular Epidemiology; D058873:Pandemics; D010802:Phylogeny; D017422:Sequence Analysis, DNA