Seroepidemiological survey of hepatitis C virus among commercial sex workers and pregnant women in Kinshasa, Democratic Republic of Congo

Background Studies conducted mainly in industrialized countries have shown that the transmission of hepatitis C virus (HCV) is mainly parenteral, and have emphasized the role of nosocomial transmission. In Equatorial Africa, the respective contributions of parenteral and non-parenteral routes of tra nsmission are unknown. The potential role of sexual transmission in this ar ea of high HCV endemicity, where sexually transmitted infections (STI) are frequent, is suggested by the fact that HCV infection is rare in infants an d young adolescents, but increases thereafter with age. The present study, conducted in Democratic Republic of Congo, was designed to determine the pr evalence of HCV infection and associated sexual risk factors in two female populations with different sexual behaviour. Methods Cross-sectional studies conducted among commercial sex workers (CSW , n=1144) and pregnant women (n=1092) in the late 1980s in Kinshasa showed a high frequency of at-risk sexual behaviour, STI and human immunodeficienc y virus (HIV) infection, particularly among CSW. We screened samples collec ted during these epidemiological studies for antibodies to HCV using a seco nd-generation ELISA with confirmation by a third-generation LIA. We also as sessed sociodemographic variables, medical history, STI markers and sexual behaviour, and their potential association with HCV infection. Results The overall prevalence of anti-HCV was 6.6% (95% CI: 5.2-8.2) among CSW and 4.3% (95% CI: 3.2-5.7) among pregnant women (age-adjusted OR = 1.5 , 95% CI : 1.0-2.1, P=0.05). Multivariate analysis showed that the presence of anti-HCV among CSW was independently associated with a previous history of blood transfusion (P<0.001), age >30 years (P<0.001) and the presence o f at least one biological marker of STI (P<0.03). No such links were found among pregnant women (although the history of blood transfusions was not in vestigated in this group). Anti-HCV was not associated with sociodemographi c variables or sexual behaviour in either group, or with individual markers of STI. Despite the high-risk sexual behaviour and the higher prevalence o f STI in CSW, the difference in HCV seroprevalence between CSW and pregnant women (6.6% versus 4.3%) was small, particularly when compared with the di fference in the seroprevalence of MV (34.1% versus 2.8%). Conclusion The role of sexual transmission in the spread of HCV seems to be limited. Parenteral transmission (including blood transfusion and injectio ns), possibly related to the treatment of STI, probably plays a major role.