Anogenital human papilloma virus and the problem of persistence.

It has been known since antiquity that genital warts (condylomata acuminata) are a sexually transmitted disease. Since the late 1970s it has become increasingly clear that infections by the same virus, human papilloma virus (HPV) are closely implicated in the aetiology of anogenital squamous cell carcinomas and in their precursors, known as dysplasia, intraepithelial neoplasia (CIN) or squamous intraepithelial lesions (SIL). The natural history of these cancer precursors is characterised by regression, persistence or progression [1]. This review examines the natural history of anogenital HPV infections, especially persistence of the virus. Other topics covered include viral transmission, pathogenesis, the natural history of the lesions and treatment strategies.