infections
Human Papillomavirus (HPV) Infection
Introduction
Human papillomavirus (HPV) can be sexually transmitted and causes changes in cells, which can lead to genital warts or to precancer or cancer of the cervix, vagina, vulva, anus, or throat. Different types of human papillomavirus (HPV) infect different parts of the body and can cause warts or precancer or cancer of the cervix, vagina, vulva, penis, anus, and throat. Genital warts are visible skin lesions that sometimes cause burning pain; genital or anal precancer or cancer may cause bleeding or a mass or have no symptoms. Doctors identify warts based on their appearance. Cervical cancer is screened for with Pap tests or HPV testing, and some people at high risk are screened for anal cancer. Genital warts are usually treated with freezing (cryotherapy) or medication applied to the warts. Vaccines can prevent most types of HPV infection that can cause genital warts or cancer. (See also Overview of Sexually Transmitted Infections (STIs) .) HPV is the most common sexually transmitted infection (STI). HPV is so common that about 80% of all sexually active people who have not been vaccinated get the virus at some point in their life. In the United States, about 14 million people become newly infected with HPV each year. Before the HPV vaccine became available, each year roughly 340,000 to 360,000 people sought care for genital warts caused by HPV. As more and more people are being vaccinated against HPV, the percentage of people with HPV infection has been decreasing. Most infections go away within 1 to 2 years, but some persist. Persistent infection caused by some types of HPV can cause certain types of cancer. There are over 100 known types of HPV. Some types cause common Warts . Other types are STIs and can cause different genital or anal infections: Genital or anal warts:These warts are caused by certain types of HPV, especially types 6 and 11. Types 6 and 11 are unlikely to cause cancer. These warts are easily visible and are usually noticed by the person with warts or by a health care practitioner. Precancer (intraepithelial neoplasia) or cancer:Other HPV types, especially types 16 and 18, infect the anogenital area (the anus and genital organs) but usually do not cause easily visible lesions. They can infect and cause changes to cells that then become precancerous or cancerous. In the anogenital area, these changes occur most commonly in the cervix, vulva, or anus, and less frequently in the urethra or on the penis. Many throat cancers are also caused by HPV. The less visible warts that can lead to precancer or cancer usually cause no symptoms. People who have a weakened immune system (immunosuppression), for example human immunodeficiency virus (HIV) infection, are at increased the risk of developing HPV-related cancer. The types of HPV that affect the genital and rectal areas are usually spread during vaginal or anal intercourse but may also be spread through other types of sexual contact. HPV can also be spread during oral sex, causing infections of the mouth and increasing the risk of throat cancer. Some types of HPV can cause cancer of the cervix, vulva, anus, penis, or throat. 