P1288 : Budd chiari syndrome (BCS) in France from a large national cohort

increased in recent years. This increase may be due to factors such as high HCV viral load in blood and semen, sex with risk of mucosal damage, a higher number of sexual partners, presence of concomitant ulcerative sexually transmitted diseases and the use of recreational drugs. The aim of our study was to investigate the dynamics of HCV transmission in an outbreak of acute hepatitis C in HIV-infected MSM in Barcelona. Methods: Between 2008 and 2013, 113 cases of acute hepatitis C in HIV-infected MSM were diagnosed in the Infectious Diseases Unit, Hospital Clinic, Barcelona. Phylogenetic analysis of the HCV NS5B gene was performed in a total of 70 patients. Viral RNA was extracted from serum samples collected from each patient at the time of diagnosis. Massive sequencing was performed using the Roche 454 GS Junior platform. To define possible transmission networks, phylogenetic trees and multidimensional scaling maps were constructed from genetic distance matrices (Da). Results: At the time of diagnosis of acute hepatitis C, 53 of the 70 (76%) patients included in the study were receiving antiretroviral therapy. HIV viral load was undetectable in 48 patients (69%) and the mean CD4 cell count was 923 cells /ul. HCV viral load was 6.37 log IU/mL (range 3.73–6.99). Thirty-five of 53 (66%) patients treated with pegIFN and ribavirin achieved a sustained virological response. The prevalence of HCV genotypes was: 4d 51% (n =36), 1a 40% (n =28), 1b 7% (n =5) and 3a 1% (n =1). Phylogenetic analysis showed the existence of at least 13 monophyletic groups: 5 of genotype 1a, 2 of genotype 1b and 6 genotype 4d. Molecular analysis showed that the genetic distances between genotype 4d viruses (Da 5.42) were significantly lower than those of the subtypes 1a (Da 18.50, p < 2.2×10−16) and 1b (Da 15.25, p < 1.1×10−6). This result may suggest the existence of a single source of infection for genotype 4d and different sources for subtypes 1a and 1b. Conclusions: HCV infection spreads rapidly among HIV-infected MSM through a local network in Barcelona. The implementation of public health campaigns and preventive measures, as well as treatment interventions with the new direct-acting antivirals will allow the development of strategies to reduce the HCV transmission of HCV within these high-risk groups.