title: Origin and epidemiological history of HIV-1 CRF14_BG.
abstract: BACKGROUND
  CRF14_BG isolates, originally found in Spain, are characterized by CXCR4 tropism and rapid disease progression. This study aimed to identify the origin of CRF14_BG and reconstruct its epidemiological history based on new isolates from Portugal.
  
  
  RESULTS
  C2V3C3 env gene sequences were obtained from 62 samples collected in 1993-1998 from Portuguese HIV-1 patients. Full-length genomic sequences were obtained from three patients. Viral subtypes, diversity, divergence rate and positive selection were investigated by phylogenetic analysis. The molecular structure of the genomes was determined by bootscanning. A relaxed molecular clock model was used to date the origin of CRF14_BG. Geno2pheno was used to predict viral tropism. Subtype B was the most prevalent subtype (45 sequences; 73%) followed by CRF14_BG (8; 13%), G (4; 6%), F1 (2; 3%), C (2; 3%) and CRF02_AG (1; 2%). Three CRF14_BG sequences were derived from 1993 samples. Near full-length genomic sequences were strongly related to the CRF14_BG isolates from Spain. Genetic diversity of the Portuguese isolates was significantly higher than the Spanish isolates (0.044 vs 0.014, P<0.0001). The mean date of origin of the CRF14_BG cluster was estimated to be 1992 (range, 1989 and 1996) based on the subtype G genomic region and 1989 (range, 1984-1993) based on the subtype B genomic region. Most CRF14_BG strains (78.9%) were predicted to be CXCR4. Finally, up to five amino acids were under selective pressure in subtype B V3 loop whereas only one was found in the CRF14_BG cluster.
  
  
  CONCLUSIONS
  CRF14_BG emerged in Portugal in the early 1990 s soon after the beginning of the HIV-1 epidemics, spread to Spain in late 1990 s as a consequence of IVDUs migration and then to the rest of Europe. CXCR4 tropism is a general characteristic of this CRF that may have been selected for by escape from neutralizing antibody response.
authors.affiliation: Unidade dos Retrovírus e Infecções Associadas, Centro de Patogénese Molecular, Faculdade de Farmácia de Lisboa, Lisboa, Portugal.
authors.forename: Inês
authors.initials: I
authors.lastname: Bártolo
authors.forename: Ana B
authors.initials: AB
authors.lastname: Abecasis
authors.forename: Pedro
authors.initials: P
authors.lastname: Borrego
authors.forename: Helena
authors.initials: H
authors.lastname: Barroso
authors.forename: Francine
authors.initials: F
authors.lastname: McCutchan
authors.forename: Perpétua
authors.initials: P
authors.lastname: Gomes
authors.forename: Ricardo
authors.initials: R
authors.lastname: Camacho
authors.forename: Nuno
authors.initials: N
authors.lastname: Taveira
mesh_terms: D057134:Antibodies, Neutralizing / Q000737:chemistry; D004247:DNA; D005260:Female; D015686:Gene Products, env / Q000378:metabolism*; D015752:Genes, env; D016678:Genome; D023281:Genomics; D015497:HIV-1 / Q000378:metabolism*; D006801:Humans; D008297:Male; D008969:Molecular Sequence Data; D010802:Phylogeny; D011174:Portugal; D019718:Receptors, CXCR4 / Q000235:genetics* / Q000502:physiology; D017422:Sequence Analysis, DNA
chemical_list: D057134:Antibodies, Neutralizing; C527276:CXCR4 protein, human; D015686:Gene Products, env; D019718:Receptors, CXCR4; D004247:DNA