Molecular analysis of intraspousal transmission of hepatitis C virus

Background/Aims: Although intraspousal transmission of hepatitis C virus (HCV) has been speculated, there is no direct evidence. Methods: To investigate whether transmission of HCV occurs by this route, 295 spouses of persons diagnosed with HCV were studied. Of these, 25 (8.8%) tested positive for anti-HCV. Next, the HCV genotype was determined by polymerase chain reaction using a mixed primer set, and cDNA was obtained in 17 of the 25 couples for comparison of the genotypes. Results: Of these 17, 14 (82.4%) spouses were shown to be infected with HCV of the same genotype. Analysis of the nucleotide sequence of putative E1 gene of eight couples having the same HCV genotype revealed that five couples had remarkably high nucleotide sequence homologies (>97%), whereas samples obtained from the remaining three couples showed relatively low homology (91–92%). Nucleotide sequence homologies were significantly higher between spouses than between non-spouse pairs of isolates. Phylogenetic analysis using the neighbor-joining method suggests that infection in these five couples probably occurred after marriage. Furthermore, none of the five couples had shared other possible transmission routes such as intravenous drug use, dental treatment or acupuncture. Conclusion: These data strongly suggest the occurrence of intraspousal transmission of HCV