Clarification of interspousal hepatitis C virus infection in acute hepatitis C patients by molecular evolutionary analyses: Consideration on sexual and non-sexual transmission between spouses

Aim: Previous studies evaluating the possibilities of interspousal sexual transmission of hepatitis C virus (HCV) have yielded many conflicting results. The aim of this study was to clarify the source of HCV infection in acute hepatitis C patients using phylogenetic analyses of nucleotide sequences of HCV E1 region. Methods: Four acute hepatitis C patients were hospitalized in 2002-2007. The diagnosis was based on medical records, laboratory tests including HCV markers, and ultrasonographic examination of the liver. In each spouse of four patients, serum HCV antibody was assayed. In the subjects whose serum HCV antibody was positive, additional tests on HCV viral load and genotype were carried out. Then phylogenetic analyses of nucleotide sequences of partial HCV E1 region (440 nucleotides) of the patients and their spouses were performed. Results: Hepatitis C virus antibody changed from negative to positive in the course of hospitalization and HCV RNA could be detected in every patient. Therefore they were diagnosed as acute hepatitis caused by HCV infection. In every spouse of four patients, HCV antibody and HCV RNA were positive. Three of four couples had the identical genotype and homogeneity of nucleotide sequences of HCV E1 region in three couples ranged from 97.9% to 100%. The results of phylogenic analyses suggested that interspousal HCV infection occurred in the three couples. Conclusion: In conclusion, interspousal infection might be one of the important sources of acute HCV infection in Japan. The usefulness of phylogenetic analysis of nucleotide sequences of HCV E1 region for clarifying interspousal HCV infection was validated.