A human papillomavirus (HPV) is a papillomavirus that infects the epidermis and mucous membranes of humans. HPV can lead to cancers of the cervix, vulva, vagina, and anus in women. In men, it can lead to cancers of the anus and penis.
Approximately 130 HPV types have been identified. Some HPV types can cause warts (verrucae), but those types don't cause cancer. Other types can cause cancer, but those types don't cause warts. Other types have no symptoms and are harmless. Most people who become infected with HPV do not know they have it.
About 30-40 HPV types are typically transmitted through sexual contact and infect the anogenital region. Some sexually transmitted HPV types may cause genital warts. Persistent infection with "high-risk" HPV types—different from the ones that cause warts—may progress to precancerous lesions and invasive cancer. HPV infection is a cause of nearly all cases of cervical cancer. However most infections with these types do not cause disease.
Most HPV infections in young females are temporary and have little long-term significance. 70% of infections are gone in 1 year and 90% in 2 years.
A cervical Papanicolaou (Pap) test is used to detect abnormal cells which may develop into cancer. A cervical examination also detects warts and other abnormal growths which become visible as white patches of skin after they are washed with acetic acid. Abnormal and cancerous areas can be removed with a simple procedure, typically with a cauterizing loop.
Pap smears have reduced the incidence and fatalities of cervical cancer in the developed world, but even so there were 11,000 cases and 3,900 deaths in the U.S. in 2008. Cervical cancer has substantial mortality in resource-poor areas; worldwide, there are 490,000 cases and 270,000 deaths.
HPV vaccines, Gardasil and Cervarix, which prevent infection with the HPV types (16 and 18) that cause 70% of cervical cancer, may lead to further decreases.