Sexually transmitted diseases (STDs) are viral or bacterial diseases spread through sexual contact. More than 20 STDs have been identified to date, and anywhere between 200 and 400 million people are infected worldwide. In the U.S. alone, over 13 million people are infected with a sexually transmitted disease every year. The only sure way to prevent the contraction of STDs is abstinence, but practicing safe sex with the use of condoms can reduce the risk of infection. Oral contraceptives can help prevent pregnancy, but they are ineffective against STDs. Make sure your condom is new and has not expired, was not stored in your wallet, has no holes or tears, and is worn properly to avoid contracting an STD from your partner – and be sure to use a condom every time.

Most common STDs:

Chlamydia
Chlamydia is the most frequently reported bacterial STD. Over 50,000 cases of this STD are reported every year, with 75 percent of cases reported by people under age 25. However, those infected with Chlamydia might not have noticeable symptoms, so estimates are closer to 3 million infected people a year. Symptoms that do appear may include a burning sensation during urination or abnormal discharge. When it spreads, it can cause permanent damage to the female reproductive system. Chlamydia can be treated with antibiotics.

Genital Herpes
Over 45 million Americans have been infected with herpes, a viral STD that leaves blisters and cold sores at the infection site. These blisters break and become sores, and outbreaks can continue throughout an infected person’s lifetime. Herpes can still be passed to sexual partners even without visible symptoms. Unlike most other STDs, herpes can’t be treated with antibiotics, but there are other prescription medicines that can lessen the severity of herpes outbreaks.

Gonorrhea
The number of people infected with gonorrhea is growing at a rapid rate. Estimates predict there are over 50,000 new cases of this STD each year, with 75 percent of cases reported by people under age 29. The female reproductive tract and men’s and women’s urethras are the most likely targets for infection. Gonorrhea symptoms include burning during urination and a yellowish-white discharge, as well as swelling of the testicles in men. Women are less likely to show symptoms, but left untreated, gonorrhea could develop into Pelvic Inflammatory Disease (PID). Treatment includes non-penicillin antibiotics.

HPV
Twenty million Americans are currently infected with HPV, and 50,000 more are infected with this STD annually. Most sexually active people are likely to contract HPV at some point in their lives, whether or not they experience visible symptoms. Visible symptoms of HPV include external genital warts or, for women, internal genital warts on the cervix. Ten percent of HPV cases cause cervical cancer, so doctors recommend annual Pap smears for all sexually active women. An HPV vaccine is now available for uninfected women ages 9 to 26.

Syphilis
Syphilis is an STD that infects over 30,000 people each year. Syphilis has several stages and is contracted through direct contact with the bacteria. To detect this STD early, look for a sore, called a chancre, which is usually painless and appears where the bacteria entered the body. Doctors can test for syphilis with a blood test, and syphilis can be treated with antibiotics.

Trich
Trich, or Trichomoniasis, is the most common STD in young sexually active women, and there are 7.4 million new cases of Trich reported by men and women in the U.S. every year. Symptoms of Trich include urinary discomfort or discharge during urination, as well as discomfort during intercourse. Symptoms of this STD appear four weeks after exposure and can be treated with prescription drugs.