Health Topics A-Z

What Are STDs?

STDs are sexually transmitted diseases. This means they are most often — but not exclusively — spread by sexual intercourse. AIDS, chlamydia, genital herpes, genital warts, gonorrhea, some forms of hepatitis, syphilis and trichomoniasis are STDs.

STDs used to be called venereal diseases or VD. They are among the most common contagious diseases. More than 65 million Americans have an incurable STD. Each year, 15.3 million new cases are reported; half of these infections are lifelong.

STDs are serious illnesses that require treatment. Some STDs, such as AIDS, cannot be cured and are deadly. By learning more about STDs, you can find out ways to protect yourself.

You can get an STD by vaginal, anal, or oral sex. You can also be infected with trichomoniasis by contact with damp or moist objects such as towels, wet clothing or toilet seats, although it is more commonly spread by sexual contact. You are at high risk if:

• You have more than one sex partner.
• You have sex with someone who has had many partners.
• You don't use a condom when having sex.
• You share needles when injecting intravenous drugs.
• You trade sex for money or drugs.

Except for AIDS and hepatitis B, sexually transmitted diseases can be cured or managed if they are treated early. You may not realize you have an STD until it has damaged your reproductive organs (rendering you infertile), your vision, your heart or other organs. Having an STD weakens the immune system and leaves you more vulnerable to other infections. Pelvic inflammatory disease is a complication of many STDs that can leave women unable to have children. It can even kill you. If you pass an STD to your newborn child, the baby may suffer permanent harm or death.

What Causes STDs?

STDs include just about every kind of infection. Bacterial STDs include chlamydia, gonorrhea and syphilis. Viral STDs include AIDS, genital herpes, genital warts (HPV) and hepatitis B. Trichomoniasis is caused by a parasite.

The germs that cause STDs hide in semen, blood, vaginal secretions, and sometimes saliva. Most of the organisms are spread by vaginal, anal, or oral sex, but some, such as those that cause genital herpes and genital warts, may be spread through skin contact. You can get hepatitis B by sharing personal items, such as toothbrushes or razors, with someone who has it.