Chlamydia is the most commonly reported STD caused by a bacterium. An infected person may not have any symptoms, and severe damage can occur in an infected woman's reproductive organs.

The following sources provide excellent information about this infection:

Centers for Disease Control

New York State Department of Health

Planned Parenthood

Women's Health.gov (National Institute of Health)

American Sexual Health Association

Young Men's Health (Boston Hospital)

Gay Men's Health