HCV Sexual Transmission in Men Who Have Sex with Men

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HCV Sexual Transmission in Men Who Have Sex with Men

By Liz Highleyman

Since the early 2000s, doctors in the U.K. and elsewhere in Europe have reported outbreaks of apparently sexually transmitted acute hepatitis C virus (HCV) infection among mostly HIV positive men who have sex with men (MSM). To date, there have been nearly 400 such cases in London and Brighton in the UK and smaller clusters in France, Germany, and the Netherlands. Similar small outbreaks have also been reported in Australia and the United States. These cases are assumed to be due to permucosal (e.g., sexual) rather than percutaneous (e.g., related to injection drug use) transmission since they have been linked to high-risk sexual practices and non-injection recreational drug use.

At the 4th International AIDS Society Conference on HIV Treatment, Pathogenesis and Prevention last week in Sydney, Australia, an international team of researchers presented data about the clustering of these infections across different countries.

The investigators studied 190 HIV positive MSM diagnosed with acute HCV infection between 2000 and 2006:

• 107 from the UK;• 51 from the Netherlands;• 24 from Germany;• 8 from France.

The mean age was about 38 years, most were taking HAART, and the mean CD4 cell count ranged from about 400-600 cells/mm3.

From the men's blood samples, the researchers amplified, sequenced, and compared parts of the NS5B region (436 base-pair) of the HCV genome and constructed phylogenetic trees to clarify relationships between cases.

Half the men had genotype 1a HCV, followed by genotype 4d (23%), 3a (7%), 1b (5%), and 2 (2%). Genotype information was not available for 24 men, who were excluded from further analysis. Compared with the overall genotype distribution in northern Europe, an unusually high proportion of men had genotype 4, which is the most predominant type in Africa and the Middle East.

Results

• 10 clusters of related HCV strains accounted for 88% of all the analyzed isolates.• The smallest cluster contained HCV from 3 men and the largest from 36 individuals.• 7 of these clusters contained strains from more than 1 country.• 4 clusters contained isolates from more than 2 countries. • One of the 2 genotype 4d clusters (the second largest overall, representing 31 men) included samples from all 4 countries.• Country-specific segregation was more common in the smaller clusters, while the larger clusters tended to include isolates from more countries.

Conclusion

The researchers concluded that this analysis reveals a large HCV transmission network among HIV positive MSM in Europe, likely facilitated by travel between cities.

They recommended that public health agencies should implementation targeted hepatitis C prevention strategies for high-risk HIV positive MSM, including education and HCV screening for at-risk individuals.

Researchers are currently conducting phylogenetic analysis to elucidate HCV infection patterns among the Australian acute hepatitis C cases, and how they might be related to the European clusters. So far, these cases have been predominantly genotype 1 or 3 (reflecting the overall distribution in Australia), not genotype 4.

UCL Institute of Hepatology, London, UK; Cluster of Infectious Disease, Health Service, Amsterdam, Netherlands; University of Oxford, Oxford, UK; Department of HIV Medicine, Royal Free Hospital, London, UK; University of Bonn, Germany; Practice Dupke, Carganico, Baumgarten, Berlin, Germany; Department of Infectious Diseases, Health Service, Rotterdam, Netherlands.

07/31/07

ReferenceM Danta, T van de Laar, D Brown, and others. Evidence of international transmission of HCV in pan-European study of HIV-positive men who have sex with men (MSM). 4th International AIDS Society Conference on HIV Pathogenesis, Treatment, and Prevention. Sydney, Australia, July 22-25, 2007. Abstract TUAB201.

http://www.hivandhepatitis.com/2007icr/ias/docs/073107_i.html