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Evidence of international transmission of HCV in pan-European study of HIV-positive men who have sex with men (MSM)
Presented by Mark Danta, United Kingdom.
Danta M.1, van de Laar T.2, Brown D.1, Pybus O.3, Bhagani S.4, Vogel M.5, Neifer S.6, Baumgarten A.6, Gotz H.7, Rockstroh J.5, Bruisten S.2, Dusheiko G.1, Coutinho R.2
1UCL Institute of Hepatology, London, United Kingdom, 2Cluster of Infectious Disease, Health Service, Amsterdam, Netherlands, 3Department of Zoology, University of Oxford, Oxford, United Kingdom, 4Department of HIV Medicine, Royal Free Hospital, London, United Kingdom, 5University of Bonn, Bonn, Germany, 6Practice Dupke, Carganico, Baumgarten, Berlin, Germany, 7Department of Infectious Diseases, Health Service, Rotterdam, Netherlands
Objective: Since 2000, there has been a reported rise in permucosal HCV transmission among European HIV-positive MSM related to high-risk sexual behaviours. We conducted a phylogenetic study to investigate the presence of a HCV transmission network among European MSM.
Methods: HIV-positive MSM diagnosed with acute HCV (n=178) in England, Netherlands and Germany between January 2000 and December 2006 were enrolled into a molecular phylogenetic study. Part of the NS5B region of the HCV genome (436 bp) was amplified using RT-PCR and subsequently sequenced and genotyped. NS5B phylogentic trees were constructed using MEGA 3.1 software, comparing MSM cases with unrelated NS5B sequences.
Results: NS5B sequences were obtained from 154/178 (87%) of cases; UK 86/107 (80%); Netherlands 46/47 (98%); Germany 22/24 (92%). Circulating HCV strains were of subtype 1a (60%), 4d (23%), 3a (8%), 1b (6%), 2b and 2c (3%). Phylogenetic analysis revealed 10 distinct HCV clusters (containing between 3-36 individuals; bootstrap values >70%) involving 129 (84%) of the sequences. Six of the ten clusters contained sequences from more than one country; 3 clusters contained sequences from all three countries. The majority (66%) of HCV sequences were in the five largest clusters, all of which contained sequences from different countries. There was a trend to country specific segregation occurring in smaller clusters compared with country non-specific clusters (4.5 median sequences/cluster versus 15.5 median sequences/cluster, p=0.07).
Conclusion: This phylogenetic analysis reveals a large HCV transmission network among HIV-positive MSM in Europe. International mixing increases with cluster size, emphasising the rapid spread of regional outbreaks to neighbouring countries, presumably through increased travel associated with high-risk behaviours. The emergence of co-circulating HCV lineages supports transmission related to behavioural change among MSM rather than intrinsic viral change. This has important implications for public health agencies mitigating HCV transmission.
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