Chlamydia

Chlamydia is caused by *Chlamydia trachomatis*, a bacterium that infects columnar epithelial cells lining the urogenital tract. It often produces little or no discomfort at the site of infection. That silence is clinically deceptive: inflammation can persist while the person feels well enough to delay testing or continue exposing partners. The major harm comes from spread beyond the initial mucosal site. Infection originating at the cervix can ascend into the upper reproductive tract and cause pelvic inflammatory disease (PID). Inflammation and subsequent scarring of the fallopian tubes create the pathway to infertility, chronic pelvic pain, and ectopic pregnancy. Urethral or genital infection can also be associated with epididymo-orchitis, and some people develop reactive arthritis. A lack of symptoms does not mean a lack of transmission or future complication. Screening and treatment interrupt both.