Human papillomavirus (HPV) is an extremely common virus. At some point in our lives most of us will catch the virus. Worldwide, HPV is the most widespread of all sexually transmitted viruses; four out of five (80%) of the world's population will contract some type of the virus once in their life . If you catch HPV, in the majority of cases the body's immune system will clear or get rid of the virus without the need for further treatment. In fact, you may not even know that you had contracted the virus.
There are over 100 identified types of HPV and each different type has been assigned a specific number. HPV infects the skin and mucosa (any moist membrane, such as the lining of the mouth and throat, the cervix and the anus). Different types affect different parts of the body, causing lesions. The majority of HPV types infect the skin on external areas of the body, including the hands and feet. For example, HPV types 1 and 2 cause verrucas on the feet .
Around 40 of the HPV types affect the genital areas of men and women, including the skin of the penis, vulva (area outside the vagina), anus, and the linings of the vagina, cervix and rectum . Around 20 of these types are thought to be associated with the development of cancer. The World Health Organization (WHO) International Association for Research on Cancer (IARC) defines 13 of these 20 types as oncogenic (cancer causing). This means there is direct evidence that they are associated with the development of cervical cancer and are considered high risk . These high-risk types of HPV are HPV 16, 18, 31, 33, 35, 39, 45, 51, 52, 56, 58, 59 and 68 . A person infected with a high-risk genital HPV will show no symptoms, so they may never even know they have it.
In addition, there are nine HPV types that may also be associated with the development of cervical cancer, these are HPV 26, 53, 64, 65, 66, 67, 69, 70, 73 and 82. However, there is currently not enough evidence to indicate that these are high-risk types for cervical cancer .
The remaining genital HPV types have been designated low risk as they do not cause cervical cancer but they can cause other problems, such as genital warts.
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