Don't Ignore the Symptoms: Sexual Problems, STDs Affect Millions

The latest estimate from the Centers for Disease Control and Prevention says that there are approximately 19 million new STD infections each year, with almost half of those occurring in teens and young adults ages 15 to 24. What's more, almost half of women have a sexual problem of some sort, according to a report today from HealthDay. Since sexually transmitted diseases often are announced only by nonspecific signs (like abdominal pain and fever), they may easily be mistaken for other illnesses—and that means the number of cases may actually be much higher. That's not good, say experts: Certain STDs, undiagnosed and untreated, can wreak havoc, bringing serious and even life-threatening consequences. Here's a list of nine serious STDs—and one that's just a nuisance:

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1. Chlamydia. Nicknamed the "silent disease," chlamydia often does its damage unnoticed; indeed, it produces virtually no symptoms in about half the men and three quarters of the women who get it, according to the CDC. But that can mean trouble, especially for women: Infertility, pelvic inflammatory disease, and dangerous ectopic pregnancies can result if the infection isn't stopped with antibiotics. While men rarely experience complications, the infection can spread to the tube that shuttles sperm, leading to pain, fever, and a remote chance of sterility. Once a woman has been infected with chlamydia, she is up to five times more likely to contract HIV if exposed to the virus. To avoid serious problems, the CDC urges—at a minimum— annual screening tests for all sexually active women ages 25 and under, as well as tests for all pregnant women. A mother's untreated chlamydia infections can invade a newborn's eyes and respiratory tract, which is why it's the leading cause of pink eye and pneumonia in infants, according to the CDC.

2. Syphilis. Once thought to be nearly eradicated in the United States, syphilis has staged a comeback in the past decade. It is most common among men with same-sex partners, although women, too, can become infected. Syphilis typically unfolds in stages, the first of which is marked by a small, often painless sore that may heal on its own (it is through direct contact with syphilis sores that the bacterial infection is spread.) If untreated, a rash of red-brown spots may pock the palms of hands and soles of feet, a sign that the infection has progressed to its second stage. Fever, swollen glands, a sore throat, hair loss, headaches, and other symptoms of this stage may emerge and resolve on their own. Without treatment, however, late-stage syphilis will develop. This can take up to 20 years, but it can involve such extensive damage to vital organs like the brain, heart, blood vessels, nerves, liver, bones, and joints that a person can't survive.