Chlamydia infection

Chlamydia infection (from the Greek, χλαμύδος meaning "cloak") is a common sexually transmitted infection (STI) in humans. It is caused by the bacterium "Chlamydia trachomatis". It can be treated with antibiotics. 
The term "Chlamydia infection" can also refer to infections caused by any species belonging to the bacterial family "Chlamydiaceae". "C. trachomatis" is only in humans. Chlamydia is a major infectious cause of human genital and eye disease.
The infection is one of the most common sexually transmitted infections in people worldwide – about 2.8 million cases of chlamydia infection occur in the United States each year. It is the most common bacterial STI in humans.
"C. trachomatis" naturally lives only inside human cells. Chlamydia can be transmitted during vaginal, anal, or oral sex. It can also be passed from an infected mother to her baby during vaginal childbirth. Many people with Chlamydia show no symptoms of infection. Between half and three-quarters of all women who have chlamydia have no symptoms and do not know that they are infected. Untreated, chlamydial infections can cause serious reproductive and other health problems with both short-term and long-term consequences.
Chlamydia conjunctivitis or trachoma is a common cause of blindness worldwide. The World Health Organization estimates that it accounted for 15% of blindness cases in 1995, but only 3.6% in 2002.