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There are more than 100 types of human papillomavirus (HPV) strains. However, only about 30 or so of those strains are actually sexually transmitted infections (STIs), which cause genital HPV and infection to the mucous membranes and skin area via skin-to-skin contact. Unfortunately, HPV is asymptomatic; people who contract this STI are many times caught unaware unless genital warts develop or it’s caught by a physician. Most men and women diagnosed with HPV avoid developing any serious symptom or health problem.

Symptoms and Health Consequences

Low-risk strains of HPV cause genital warts, while high-risk strains could cause cervical or other uncommon forms of cancer. Those who test positive for HPV are classified in either the low- or high-risk category depending on the results of a biopsy. Regardless of classification, about 90 percent of those infected find that the immune system naturally takes care of the infection within two years' time.

Becoming Infected with HPV

HPV is not a hereditary infection, as it is passed through genital contact during vaginal or anal intercourse. In rare cases, pregnant women do accidentally pass HPV to newborns during vaginal delivery. The baby could get genital warts in the throat, otherwise known as recurrent respiratory papillomavirus (RRP). However, it is not recommended for pregnant women with genital warts to choose a cesarean, as there is no evidence that cesarean births prevent RRP in newborns.

Genital Warts and Cancer

Normal skin and mucous membranes infected with HPV can eventually become abnormal. But again, 90 percent of the infections become neutralized by the immune system, causing abnormal cells to revert back to normal healthy cells. High-risk HPV strains not neutralized by the immune system can stay in the body for years, turning those abnormal cells eventually into cancerous cells. Ten percent of women with high-risk strains in the cervix develop long-lasting infections and have increased risk of cervical cancer. People infected in the penis, vulva or vaginal area risk developing cancer in those areas, though this is considered less common than cervical cancer.

HPV statistics

Five to six million Americans are newly infected with genital HPV annually. At any given time, about 20 million Americans are actively infected with HPV. The Centers for Disease Control and Prevention (CDC) states that 50 percent of men and women contract HPV at some point in their lifetimes. Furthermore, the American Cancer Society estimates that in 2009 over 11,000 women will get cervical cancer, and over 4,000 will succumb to the disease. However, the death rate is declining by about 4 percent each year due to more women obtaining regular screening.

HPV prevention

While condoms lower the risk of acquiring HPV, they will not protect areas not covered with a condom and are therefore not 100 percent effective. The most important thing for girls and women is to protect themselves against cervical cancer. The HPV vaccine protects against most forms of cervical cancers, but not all. The vaccine is generally recommended for girls age 11-12, and girls and women age 13 to 26 who did not get the vaccine when they were younger. Routine cervical cancer screenings are also crucial. Unfortunately, no vaccine has been successfully created for men with HPV; furthermore, there are no screenings yet for early detection of penile or anal cancer.