What Are STDs?
Sexually transmitted diseases (STDs), also known as sexually transmitted infections (STIs), are very common. Millions of new infections occur every year in the United States.
STDs pass from one person to another through vaginal, oral, and anal sex. They also can spread through intimate physical contact like heavy petting, though this is not very common.
STD or STI?
A sexually transmitted infection (STI) is a virus, bacteria, fungus, or parasite people can get through sexual contact. Many STIs have no symptoms, so people can have an infection but not know it. A sexually transmitted disease (STD) develops because of an STI and the term implies that the infection has led to some symptom of disease. People sometimes use the terms in one another’s place.
If I get an STD, how will I know?
Many STDs don’t cause any symptoms that you would notice. The only way to know for sure if you have an STD is to get tested. You can get an STD from having sex with someone who has no symptoms. Just like you, that person might not even know he or she has an STD.