title: Molecular epidemiology of HIV type 1 infection in Portugal: high prevalence of non-B subtypes.
abstract: In this study, we have investigated the diversity of current HIV-1 strains circulating in the metropolitan area of Lisbon, Portugal. A total of 217 HIV-1-positive blood samples, collected between October 1998 and December 2000, was genetically characterized in the gp120 C2V3C3 region (n = 205) or part of the gp41 N-terminal segment (n = 12) by heteroduplex mobility assay (HMA) and/or DNA sequencing. The HMA subtyping efficiency (number of samples unambiguously subtyped by HMA divided by the total number of samples subtyped) was 65.9% (143 of 217), with indeterminate migration patterns of subtype A and G strains contributing significantly to this value. On the overall, subtype B was the most prevalent (50.2%), followed by subtypes G (21.7%), A (17.5%), and F (5.5%), whereas subtypes C, D, H, and J accounted altogether for 5.1% of the infections. Non-B subtypes were responsible for 77.4 and 33.1% of the infections among African immigrants and Portuguese subjects, respectively. Angolan individuals (n = 25) were the only ones infected with all the HIV-1 subtypes documented, probably reflecting a high degree of viral genetic diversification in their country of origin. Phylogenetic analysis showed a predominance of IbNG-like viruses among subtype A sequences and two new major subclusters within subtype G (G(P) and G(P)'). The majority of the Portuguese G sequences described formed a well-defined subcluster (G(P)), supported by bootstrap values >90%, phylogenetically distant from clade G sequences in databases. gag (p24/p7) sequence analysis of these variants confirmed the maintenance of the subtype G subclusters. The multiple subclustering observed for the major clades A, B, D, and G, as well as the variety of subtypes found, indicate a high diversity of HIV-1 variants circulating in Portugal and suggest a need for continuous epidemiologic surveillance.
authors.affiliation: Unidade de Virologia/Unidade de Parasitologia e Microbiologia Médicas, Instituto de Higiene e Medicina Tropical, Universidade Nova de Lisboa, P-1349-008 Lisbon, Portugal. aidaesteves@ihmt.unl.pt
authors.forename: Aida
authors.initials: A
authors.lastname: Esteves
authors.forename: Ricardo
authors.initials: R
authors.lastname: Parreira
authors.forename: Teresa
authors.initials: T
authors.lastname: Venenno
authors.forename: Margarida
authors.initials: M
authors.lastname: Franco
authors.forename: João
authors.initials: J
authors.lastname: Piedade
authors.forename: José
authors.initials: J
authors.lastname: Germano De Sousa
authors.forename: Wanda F
authors.initials: WF
authors.lastname: Canas-Ferreira
mesh_terms: D000293:Adolescent; D000328:Adult; D017954:Africa South of the Sahara / Q000208:ethnology; D000368:Aged; D000595:Amino Acid Sequence; D001483:Base Sequence; D016384:Consensus Sequence; D004279:DNA, Viral / Q000032:analysis; D005260:Female; D014644:Genetic Variation; D015699:HIV Envelope Protein gp120 / Q000235:genetics; D015658:HIV Infections / Q000453:epidemiology* / Q000821:virology*; D015497:HIV-1 / Q000235:genetics* / Q000302:isolation & purification*; D006801:Humans; D008297:Male; D008875:Middle Aged; D017720:Molecular Epidemiology; D008969:Molecular Sequence Data; D010802:Phylogeny; D011174:Portugal / Q000453:epidemiology; D015995:Prevalence
chemical_list: D004279:DNA, Viral; D015699:HIV Envelope Protein gp120