Absence of intrafamilial transmission of hepatitis C virus and low risk for sexual transmission in rural central Africa indicate a cohort effect.

BACKGROUND

Intrafamilial and sexual transmission of hepatitis C virus (HCV) are still being debated, and little is known about such transmission in central Africa.

OBJECTIVE

To examine the rate of intrafamilial transmission of HCV between patients and their household members.

STUDY

DESIGN

A cross-sectional study was conducted in Dienga, a remote village in Gabon, involving 195 household members of 14 index cases of HCV infection. After a questionnaire on the risk factors for parenteral exposure, blood samples were obtained and tested for antibody to HCV by an enzyme immunoassay (Monolisa anti-HCV plus version 2). Positive samples were tested for HCV RNA and genotyped by amplification and phylogenetic analysis of a fragment of the NS5B gene.

RESULTS

HCV antibody was found in 13/195 (6.7%) household contacts, comprising 5/14 (35.7%) sexual partners and 8/114 (7%) relatives. None of the children of index patients tested positive. HCV RNA was detected in only five household members with HCV antibody. The same genotypes were found in only two of five couples, both couples being sexual partners. Parenteral risk factors were not more likely to be reported by people positive for HCV antibody than by those who were negative. Age over 50 years was the only independent predictor of positivity for HCV antibody.

CONCLUSIONS

This study indicates, as previously suggested, that the spread of HCV in central Africa is due to a cohort effect, with previous, possibly iatrogenic, transmission rather than intrafamilial or sexual transmission.