Chlamydia is a sexually transmitted disease (STD) that is caused by the bacterium Chlamydia trachomatis. Since approximately 75% of women and 50% of men have no symptoms, most people infected with chlamydia are not aware of their infections and therefore may not seek health care. When diagnosed, chlamydia can be easily treated and cured by conventional medical means. Untreated, chlamydia can cause severe and costly reproductive and other health problems which include both short- and long-term consequences, including pelvic inflammatory disease (PID) which is the critical link to infertility, and potentially fatal tubal pregnancy.