Genital warts.

Human papillomaviruses have not been propagated in tissue culture, so they cannot be studied by the procedures of classical virology. Recently, DNA hydridization techniques and restriction enzyme analysis have revealed that multiple strains of human papillomaviruses exist. It is now accepted that genital warts are a sexually transmitted disease; other routes of infection are possible, but unusual. An association between maternal warts during pregnancy and the development of vulval warts and laryngeal papillomatosis in infants and young children has been shown. The epidemiology of anal warts in homosexual men is not well understood. The flat condyloma, visible on colposcopy, is a human papillomavirus-containing lesion with a wart-like histology. It is a common condition which in the past may have been mistaken for dysplasia. Flat condylomas may regress spontaneously, or develop into condylomata acuminata. A link between these lesions and some cases of cervical carcinoma has been suggested.