Hepatitis C Virus Infection in Guinea-Bissau: A Sexually Transmitted Genotype 2 with Parenteral Amplification?

Background. Sub-Saharan Africa is the continent with the highest prevalence of Hepatitis C virus (HCV) infection. Genotype 2 HCV is thought to have originated from West Africa several hundred years ago. Mechanisms of transmission remain poorly understood. Methodology/Principal Findings. To delineate mechanisms for HCV transmission in West Africa, we conducted a cross-sectional survey of individuals aged >= 50 years in Bissau, Guinea-Bissau. Dried blood spots were obtained for HCV serology and PCR amplification. Prevalence of HCV was 4.4% (47/1066) among women and 5.0% (27/544) among men. In multivariate analysis, the independent risk factors for HCV infection were age (baseline: 50-59 y; 60-69 y, adjusted odds ratio [AOR]: 1.67, 95% CI: 0.91-3.06; >= 70 y, AOR: 3.47, 95% CI: 1.89-6.39), belonging to the Papel, Mancanha, Balanta or Mandjako ethnic groups (AOR: 2.45, 95% CI: 1.32-4.53), originating from the Biombo, Cacheu or Oio regions north of Bissau (AOR: 4.16, 95% CI: 1.18-14.73) and having bought or sold sexual services (AOR: 3.60, 95% CI: 1.88-6.89). Of 57 isolates that could be genotyped, 56 were genotype 2. Conclusions. Our results suggest that transmission of HCV genotype 2 in West Africa occurs through sexual intercourse. In specific locations and subpopulations, medical interventions may have amplified transmission parenterally.