title: The impact of immigration on env HIV-1 subtype distribution among heterosexuals in the Netherlands: influx of subtype B and non-B strains.
abstract: OBJECTIVE
  To examine the epidemiological factors influencing the distribution and spread of HIV-1 subtypes among heterosexuals in the Netherlands.
  
  
  METHODS
  A nationwide serosurveillance in 21 HIV/AIDS centres from 1997 to 1999 involved 200 individuals for whom the mode of HIV transmission was heterosexual contact or unknown. HIV-1 subtypes were determined by phylogenetic analysis of env V3 sequences and correlated with sociodemographic characteristics of the subjects and their sexual partners.
  
  
  RESULTS
  HIV-1 subtype B infection occurred in 121 subjects (60%). Non-B subtypes were identified in 31 (A), 24 (C), 10 (D), six (E), four (F) and three (G) individuals; one had an unclassified subtype. The proportion of subtype B was about 60% in four of the six regions of the Netherlands, but in the Northwest and Southwest regions these proportions were 76% and 46%, respectively. The Surinamese and Antilleans, large immigrant groups, were all infected with subtype B, as were almost all individuals with an unknown source. The proportions of non-B viruses did not change significantly over time in Amsterdam, where subtyping was available from 1988 onward, but a shift in the various subtype B strains was observed, suggesting introductions of new subtype B strains in Amsterdam.
  
  
  CONCLUSIONS
  To date, HIV-1 non-B subtypes in the Netherlands are still found predominantly among heterosexuals with an epidemiological link with sub-Saharan Africa. Despite continuing introductions of non-B subtypes, the B/non-B distribution has been stable over time, most likely as a result of introductions of subtype B strains from Caribbean and South American countries.
authors.affiliation: Department of Infectious Diseases Epidemiology, National Institute for Public Health and the Environment, Bilthoven, The Netherlands.
authors.forename: E L
authors.initials: EL
authors.lastname: Op de Coul
authors.forename: R A
authors.initials: RA
authors.lastname: Coutinho
authors.forename: A
authors.initials: A
authors.lastname: van der Schoot
authors.forename: G J
authors.initials: GJ
authors.lastname: van Doornum
authors.forename: V V
authors.initials: VV
authors.lastname: Lukashov
authors.forename: J
authors.initials: J
authors.lastname: Goudsmit
authors.forename: M
authors.initials: M
authors.lastname: Cornelissen
mesh_terms: D005260:Female; D018740:Genetic Heterogeneity; D015699:HIV Envelope Protein gp120 / Q000145:classification* / Q000235:genetics; D015658:HIV Infections / Q000097:blood / Q000453:epidemiology / Q000635:transmission / Q000821:virology*; D015497:HIV-1 / Q000145:classification* / Q000235:genetics / Q000302:isolation & purification; D020010:Heterosexuality; D006801:Humans; D008297:Male; D009426:Netherlands / Q000453:epidemiology; D010446:Peptide Fragments / Q000145:classification* / Q000235:genetics; D010802:Phylogeny; D011159:Population Surveillance; D012307:Risk Factors
chemical_list: D015699:HIV Envelope Protein gp120; C059762:HIV envelope protein gp120 (305-321); D010446:Peptide Fragments