Hand-genital transmission of genital warts? An analysis of prevalence data.

The role of hand-genital transmission in the aetiology of genital warts is unclear. However this route is suggested by a number of observations including the relatively high proportion of genital warts in children which contain HPV types 1-4 (15% for children and 2% for adults). We compared two transmission models; one which assumes that hand-genital transmission occurs and one that it does not, and determined the conditions in which each model can reflect the available prevalence data. Hand-genital transmission provides a simple explanation of the observed differences in the proportions of genital warts containing HPV types 1-4 and 6/11 in children and adults. If hand-genital transmission does not occur, the observed difference could only be explained by an eightfold greater probability of transmission to children of types 1-4 than types 6/11, or by an eightfold greater duration of infection with types 1-4. Our findings provide support for the view that genital warts may be transmitted by hand-genital contact.