This virus is a sexually-transmitted infection that causes genital warts and cervical lesions, and is thought to be responsible for most cases of cervical cancer; women whose HPV infections persist over time are thought to be at the greatest risk of cancer. Genital warts can develop on the cervix, penis, or in the urethra, vagina, anus or rectum. They look like other sorts of warts; they are dry and painless, firm and rough in texture, and can be grayish or skin colored. If left untreated, warts can grow together in clumps that resemble tiny pieces of cauliflower. They may itch slightly; flat warts may not be very noticeable. Many people may have this infection and not realize it. HPV is mainly transmitted via sexual intercourse (vaginal, oral or anal intercourse) and it may also be transmitted by sharing damp unwashed articles like washcloths, towels or underwear. The disease is highly contagious, but the risk of transmission can be reduced by using a condom during sex. Treatment involves burning off the warts with liquid nitrogen or lasers or by applying prescription creams (most containing podophyllotoxin)that kill the virus. There are no over-the-counter drugs that can treat this sort of infection.