What is human papillomavirus? The human papillomaviruses (also known as HPV) are a group of more than 150 viruses, 40 of which are known to infect the genital areas. Other types infect the skin and the lining of the throat. It is possible to be infected with HPV without knowing you have it, and the majority of infections do not produce any symptoms. HPV affects both men and women and can cause warts, or papillomas, on the genitals and around the anus, as well as at other sites. The virus is passed through direct contact, including sexual contact. HPV is the most common sexually transmitted infection (Source: CDC). Certain strains of HPV can cause precancerous changes in cells in the area where the infection occurs. The infection can lead to different types of cancers, including cervical cancer in women. Cancer-causing HPVs are referred to as high-risk, carcinogenic, or oncogenic HPVs. HPV infection is also linked to cancers of the oral cavity, anus, penis, vagina and vulva. Approximately 50% of sexually active men and women will have HPV at some point in their lives. Approximately 20 million Americans have HPV, with six million new cases occurring each year (Source: CDC). Symptoms of HPV include warts on the genital areas that may appear small or large, flat or raised, or cauliflower shaped. Warts can also appear in the throat, in a condition called recurrent respiratory papillomatosis. Skin (cutaneous) warts are also caused by certain types of HPV. HPV does not always cause symptoms, but it is highly contagious. People do not always realize they have it and may transmit the virus unknowingly. Seek prompt medical care if you suspect that you or your partner may have contracted or may be at risk for HPV infection.