Sexually transmitted diseases, commonly called STDs, are diseases that are spread by having sex with someone who has an STD.
You can get a sexually transmitted disease from sexual activity that involves the mouth, anus, vagina, or penis.
Depending on the disease, some untreated STIs can lead to infertility, chronic pain or even death.
Twenty-seven different viruses have been identified in semen.
You can get an STI by having unprotected sex with a partner who's infected.
The most effective way to prevent sexual transmission of STIs is to avoid contact of body parts or fluids which can lead to transfer with an infected partner.Many STIs are (more easily) transmitted through the mucous membranes of the penis, vulva, rectum, urinary tract and (less often—depending on type of infection) the mouth, throat, respiratory tract and eyes.The visible membrane covering the head of the penis is a mucous membrane, though it produces no mucus (similar to the lips of the mouth).In fact, many people have an STI without knowing it.That's why you have to be vigilant about STI prevention.Some doctors, however, may provide additional antibiotics to be given to your partner so that you can be treated at the same time.