HPV stands for human papillomavirus (pronounced pap ah LO mah), but there are actually more than 100 related viruses in this group. Each HPV virus is given a number or type. The term "papilloma" refers to a kind of wart that results from some HPV types.
HPV lives in the body's epithelial cells. These are flat and thin cells found on the skin's surface and also on the surface of the vagina, anus, vulva, cervix, penis head, mouth, and throat.
Of the 100 HPV types, about 60 types cause warts on areas such as the hands or feet. The other 40 or so types of HPV are sexually transmitted and are drawn to the body's mucous membranes, such as the moist layers around the anal and genital areas.
How HPV Spreads
These sexually-transmitted HPV viruses are spread through contact with infected genital skin, mucous membranes, or bodily fluids, and can be passed through intercourse and oral sex. HPV can infect skin not normally covered by a condom, so using a condom does not fully protect someone from the virus. Also, many people don't realize they're infected with HPV and may have no symptoms, so neither sexual partner may realize that the virus is being spread.
High-Risk HPV, Low-Risk HPV
Not all of the 40 sexually transmitted HPV viruses cause serious health problems. High-risk HPV strains include HPV 16 and 18, which cause about 70% of cervical cancers. Other high-risk HPV viruses include 31, 33, 45, 52, 58, and a few others.
Low-risk HPV strains, such as HPV 6 and 11, cause about 90% of genital warts, which rarely develop into cancer. Genital warts can look like bumps or growths. Sometimes they are shaped like cauliflower. The warts can show up weeks or months after exposure to an infected sexual partner.