title: Molecular epidemiology of HIV-1 in Iceland: Early introductions, transmission dynamics and recent outbreaks among injection drug users.
abstract: The molecular epidemiology of HIV-1 in Iceland has not been described so far. Detailed analyses of the dynamics of HIV-1 can give insights for prevention of virus spread. The objective of the current study was to characterize the genetic diversity and transmission dynamics of HIV-1 in Iceland. Partial HIV-1 pol (1020bp) sequences were generated from 230 Icelandic samples, representing 77% of all HIV-1 infected individuals reported in the country 1985-2012. Maximum likelihood phylogenies were reconstructed for subtype/CRF assignment and determination of transmission clusters. Timing and demographic growth patterns were determined in BEAST. HIV-1 infection in Iceland was dominated by subtype B (63%, n=145) followed by subtype C (10%, n=23), CRF01_AE (10%, n=22), sub-subtype A1 (7%, n=15) and CRF02_AG (7%, n=15). Trend analysis showed an increase in non-B subtypes/CRFs in Iceland over the study period (p=0.003). The highest proportion of phylogenetic clustering was found among injection drug users (IDUs; 89%), followed by heterosexuals (70%) and men who have sex with men (35%). The time to the most recent common ancestor of the oldest subtype B cluster dated back to 1978 (median estimate, 95% highest posterior density interval: 1974-1981) suggesting an early introduction of HIV-1 into Iceland. A previously reported increase in HIV-1 incidence among IDUs 2009-2011 was revealed to be due to two separate outbreaks. Our study showed that a variety of HIV-1 subtypes and CRFs were prevalent in Iceland 1985-2012, with subtype B being the dominant form both in terms of prevalence and domestic spread. The rapid increase of HIV-1 infections among IDUs following a major economic crisis in Iceland raises questions about casual associations between economic factors, drug use and public health.
authors.affiliation: Lund University, Department of Translational Medicine, Malmö, Sweden. Electronic address: malik.sallam@med.lu.se.
authors.forename: Malik
authors.initials: M
authors.lastname: Sallam
authors.affiliation: University of Oxford, Nuffield Department of Medicine, Oxford, UK; Karolinska Institute, Microbiology, Tumor and Cell Biology, Stockholm, Sweden. Electronic address: joakim.esbjornsson@med.lu.se.
authors.forename: Joakim
authors.initials: J
authors.lastname: Esbjörnsson
authors.affiliation: Landspitali University Hospital, Department of Virology, Reykjavik, Iceland. Electronic address: geb@landspitali.is.
authors.forename: Guðrún
authors.initials: G
authors.lastname: Baldvinsdóttir
authors.affiliation: University of Iceland, Faculty of Medicine, School of Health Sciences, Reykjavik, Iceland. Electronic address: hlynurind@gmail.com.
authors.forename: Hlynur
authors.initials: H
authors.lastname: Indriðason
authors.affiliation: Landspitali University Hospital, Department of Virology, Reykjavik, Iceland. Electronic address: thorabbj@landspitali.is.
authors.forename: Thora Björg
authors.initials: TB
authors.lastname: Björnsdóttir
authors.affiliation: Lund University, Department of Translational Medicine, Malmö, Sweden. Electronic address: anders.widell@med.lu.se.
authors.forename: Anders
authors.initials: A
authors.lastname: Widell
authors.affiliation: University of Iceland, Faculty of Medicine, School of Health Sciences, Reykjavik, Iceland; Landspitali University Hospital, Department of Infectious Diseases, Reykjavik, Iceland. Electronic address: magnusgo@landspitali.is.
authors.forename: Magnús
authors.initials: M
authors.lastname: Gottfreðsson
authors.affiliation: Landspitali University Hospital, Department of Virology, Reykjavik, Iceland; University of Iceland, Faculty of Medicine, School of Health Sciences, Reykjavik, Iceland. Electronic address: arthur@landspitali.is.
authors.forename: Arthur
authors.initials: A
authors.lastname: Löve
authors.affiliation: Lund University, Department of Translational Medicine, Malmö, Sweden. Electronic address: patrik.medstrand@med.lu.se.
authors.forename: Patrik
authors.initials: P
authors.lastname: Medstrand
mesh_terms: D000328:Adult; D016000:Cluster Analysis; D004196:Disease Outbreaks; D055030:Drug Users / Q000706:statistics & numerical data; D005260:Female; D005838:Genotype; D015658:HIV Infections / Q000453:epidemiology* / Q000635:transmission* / Q000821:virology; D015497:HIV-1 / Q000145:classification / Q000235:genetics* / Q000302:isolation & purification; D020010:Heterosexuality / Q000706:statistics & numerical data; D018451:Homosexuality, Male / Q000706:statistics & numerical data; D006801:Humans; D007055:Iceland / Q000453:epidemiology; D008297:Male; D008875:Middle Aged; D017720:Molecular Epidemiology; D058889:Molecular Typing; D010802:Phylogeny; D015995:Prevalence; D012307:Risk Factors; D012959:Socioeconomic Factors
keywords: BEAST; Heterosexual; MSM; Non-subtype B; Phylogeny; Subtype B