Human papilloma virus infections

Abstract

Human papillomaviruses (HPVs) infect only epithelial cells of the skin or mucous membranes. Infectivity varies greatly depending on the amount of virus particles present, the type and intensity of contact, and the immune status of the infected person. To date, more than 200 human papillomavirus genotypes have been distinguished, divided into genital, cutaneous, and wart-associated types, about half of which cause infections in the genital tract. Using very sensitive methods, several HPV types can be detected in a wart, but there is only one HPV type with a high viral load (>1 copy per cell) that triggers this disease. Partially identified HPV sequences suggest the existence of more than 50 other HPV types. The extraordinary diversity of papillomaviruses is the result of evolution over several hundred million years.