A sexually transmitted infection (STI) is an infection you can get by having sex. Some STIs (such as gonorrhea ;and chlamydia) infect your sexual and reproductive organs. Others (such as HIV, hepatitis B and syphilis) cause general body infections. STIs used to be called VDs, or venereal diseases.
STIs are very common in people under age 25. If you're sexually active, get tested!
STIs can be transmitted from one person to another during vaginal, anal and oral sex. Some STIs (HIV and hepatitis B) are also spread by contact with infected blood. STIs are not normally spread by digital sex (fingering); however, unclean hands or uncut nails can cause genital problems.
Most STI germs live in warm, moist areas. That's why they infect the mouth, rectum and sex organs (vagina, vulva, penis and testes).
Most STIs can be cured if you seek treatment. Many STIs are asymptomatic, meaning you have no symptoms. However, you still have the STI until you get treated Some STIs cannot be cured.