An STD, or sexually transmitted disease, is an infection that is passed from one person to another through sexual contact. STDs can be caused by bacteria, viruses, or parasites.

The most common STDs include:

• Chlamydia
• Gonorrhea
• Herpes
• HIV
• HPV
• Syphilis
• Trichomoniasis

STDs can be transmitted through vaginal sex, anal sex, and oral sex. They can also be transmitted through sharing needles or other drug paraphernalia.

The symptoms of STDs can vary depending on the type of infection. Some STDs, such as chlamydia and gonorrhea, may not cause any symptoms at all. Other STDs, such as herpes and syphilis, can cause painful sores or blisters.

The best way to prevent STDs is to abstain from sexual contact. However, if you do choose to have sex, there are a number of things you can do to reduce your risk of getting an STD, such as:

• Using a condom every time you have sex
• Getting vaccinated against HPV and hepatitis B
• Getting tested for STDs regularly

Most STDs can be treated with antibiotics. However, some STDs, such as HIV and herpes, are incurable.

If left untreated, STDs can lead to serious complications, such as infertility, pelvic inflammatory disease, and cancer.