Most people who have genital HPV infections do not develop visible symptoms and thus are unaware that they are infected (Centers for Disease Control, 2009g). Visible warts, which have an average incubation period of about 3 months, may appear within weeks or months after sexual contact with an infected person.

In women genital warts most commonly appear on the bottom part of the vaginal opening. They can also occur on the perineum, the labia, the inner walls of the vagina, and the cervix. In men genital warts commonly occur on the glans, foreskin, or shaft of the penis (see I Figure 15.5). Genital warts can also occur in the anus of either sex (Wieland, 2012). In moist areas (such as the vaginal opening and under the foreskin), genital warts are pink or red and soft, with a cauliflower-like appearance. On dry skin areas they are generally hard and yellow-gray.

If left untreated, genital warts may disappear, remain unchanged, or increase in size and number (Centers for Disease Control, 2009g). A healthy immune system often suppresses the virus, and most infected people with an effective immune response will become HPV-negative in 6-24 months after the initial positive test for the virus.

Genital warts are sometimes associated with serious complications. They can invade the urethra, causing urinary obstruction and bleeding. Research has also revealed an association between HPV infection and cancers of the cervix, vagina, vulva, urethra, penis, and anus (Giuliano et al., 2011; Kim, 2011). The types of HPV that cause genital warts are not the same as the types that can cause cancer (Centers for Disease Con­trol, 2009g). Recent evidence indicates that HPV infections account for 85-90% of the attributable risk for the development of cervical cancer, which is the second most common cancer diagnosed in women worldwide and the leading cause of death from

cancer among women in developing nations, where it kills about 250,000 women each year (Centers for Disease Control, 2009g; McNeil, 2011). However, there is actually little risk that a woman infected with HPV will develop cervical cancer unless the virus remains undetected and untreated (Centers for Disease Control, 2009g). This is the reason that regular Pap testing and appropriate follow-up treatment for precancer­ous lesions are essential to prevent most women from getting cervical cancer (Kahn & Hillard, 2006). A spokeswoman for the CDC recently stated that physicians often test young women for strains of HPV that are not associated with cervical cancer and thus needlessly subject women to unnecessary invasive tests (Saraiya in Neergaard, 2011).

Another rare but serious complication of HPV is that pregnant women infected with the virus can transmit it to their babies during birth (Rintala et al., 2005). Infected infants can develop a condition known as respiratory papillomatosis, which results from HPV infection of their upper respiratory tracts. Respiratory papillomatosis can have serious health consequences that produce lifelong distress and require multiple surgeries.