Molecular and epidemiological aspects of hepatitis C virus infection among crack cocaine users.

The aim is to investigate the prevalence, risk factors, and hepatitis C virus (HCV) genotypes/subtypes among crack users in-treatment in Central Brazil. A cross-sectional survey in which 600 in-treatment crack users were interviewed and tested for anti-HCV Ab by enzyme-linked immunosorbent assay was conducted between August 2012 and April 2013. Anti-HCV-positive samples were also submitted for HCV RNA detection by polymerase chain reaction. Positive HCV RNA samples were genotyped by direct sequencing analysis of the NS5B region of the viral genome, followed by phylogenetic analysis. Of the total, 3.7% (95.0% CI, 2.4%-5.6%) were anti-HCV positive. Age over 40 years and history of injecting drugs were risk factors for HCV, while snorting cocaine was a protector variable. HCV RNA was detected in 14 of 22 anti-HCV-positive samples, and the genotypes 1 (n = 10) and 3 (n = 2), subtypes 1a (n = 7), 1b (n = 3), and 3a (n = 2) were identified. The HCV prevalence found among crack users is almost threefold that observed in the general population in Brazil supporting that this population is at higher risk for HCV. The findings of cocaine insufflation as a protective behavior for HCV infection in this population should be explored.