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The origin and emergence of an HIV-1 epidemic: from introduction to endemicity

Bruhn, Christian A.W.a,b; Audelin, Anne M.c; Helleberg, Maried,e; Bjorn-Mortensen, Karenf; Obel, Nielsd; Gerstoft, Jand; Nielsen, Clausc; Melbye, Madsf; Medstrand, Patrikb; Gilbert, M. Thomas P.a; Esbjörnsson, Joakimb,g,h,i

doi: 10.1097/QAD.0000000000000198
Epidemiology and Social

Objectives: To describe, at patient-level detail, the determining events and factors involved in the development of a country's HIV-1 epidemic.

Design: Clinical information for all recorded Greenlandic HIV-1 patients was analysed and correlated with both novel and previously analysed pol sequences, representing more than half of the entire Greenlandic HIV-1 epidemic. Archival blood samples were sequenced to link early infection chain descriptions to the subsequent epidemic.

Methods: In-depth phylogenetic analyses were used in synergy with clinical information to assess number of introductions of HIV-1 into Greenland, the source of geographic origin, time of epidemic introduction and its epidemiological characteristics such as initial transmission chain, geographic dispersal within Greenland, method of infection, cluster size, sociological and behavioural factors.

Results: Despite its small population size and isolated geographic location, data support at least 25 introductions of HIV-1 into Greenland. Only a single of these led to an epidemic. This introduction occurred between 1985 and 1986, and the epidemic cluster is still active. Facilitating factors for the emergence and spread of the epidemic cluster include a rapid transition from MSM to heterosexual spread, high prevalence of other sexually transmitted diseases, rapid dispersal to larger cities and early emergence in a distinct subpopulation with high-risk behaviour including disregard for condomizing.

Conclusions: The synergistic use of disparate data categories yields such unique detail, that the Greenland epidemic now serves as a model example for the epidemic emergence of HIV-1 in a society. This renders it suitable for testing of present and future sequence-based epidemiological methodologies.

aCentre for GeoGenetics and Section for Evolutionary Genomics, Natural History Museum of Denmark, University of Copenhagen, Copenhagen, Denmark

bDepartment of Laboratory Medicine Malmö, Lund University, Malmö, Sweden

cMicrobiological Diagnostics and Virology, Statens Serum Institut, Copenhagen

dDepartment of Infectious Diseases, Copenhagen University Hospital, Rigshospitalet

eFaculty of Health and Medical Sciences, University of Copenhagen

fDepartment of Epidemiology Research, Statens Serum Institut, Copenhagen, Denmark

gNuffield Department of Medicine, NDM Research Building, University of Oxford, Oxford, UK

hDepartment of Microbiology, Tumor and Cell biology (MTC), Karolinska Institute, Stockholm, Sweden

iREGA Institute, Katholieke Universiteit, Leuven, Belgium.

Correspondence to Christian A.W. Bruhn, Centre for GeoGenetics, Oester Voldgade 5-7, 1350 Copenhagen K, Denmark. E-mail: christianwbruhn@gmail.com

Received 3 November, 2013

Revised 19 December, 2013

Accepted 2 January, 2014

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© 2014 Lippincott Williams & Wilkins, Inc.