Causes

By definition, sexually transmitted diseases occur as a result of having sexual contact with someone who has or is carrying the disease.

Herpes: This is caused by a herpes virus.

Chlamydia: This disease is caused by a bacterium called Chlamydia trachomatis.

Genital warts: These can be caused by one of over 100 different types of human papilloma virus.

Syphilis: The bacterium called Treponema pallidum causes the disease.

Gonorrhea: This is caused by a bacterium called Neisseria gonorrhoeae.

Pelvic inflammatory disease (PID): The infection is mainly caused by Chlamydia and gonorrhea although other bacteria can also cause it. When disease-causing organisms migrate upward from the urethra and cervix into the upper genital tract, PID can occur.

Trichomoniasis: This is caused by a microscopic organism called Trichomonas vaginalis.

HBV: This is caused by the hepatitis B virus.

AIDS: This is a STD caused by the Human Immunodeficiency Virus (HIV). AIDS can also be transmitted nonsexually through shared needles or blood transfusions from someone with the infection.

More on Sexually Transmitted Diseases

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This article was reviewed and updated June 2007.