Chlamydia

Chlamydia is a sexually transmitted infectious disease caused by the bacterium Chlamydia trachomatis. In the United States, it is the most commonly reported bacterial infection. Globally, it is the most common sexually transmitted infection. It causes an ocular infection called "trachoma," which is the leading infectious cause of blindness worldwide.

In females, the cervix is the anatomic site that is most commonly infected. This can manifest as cervicitis, urethritis, pelvic inflammatory disease, perihepatitis, or proctitis. Chlamydial infections in women, especially if untreated, increase the risk of infertility and ectopic pregnancy, leading to high medical costs. There are also risks if a woman has an infection during pregnancy. Additionally, infants born vaginally to mothers infected with genital Chlamydia trachomatis may develop conjunctivitis and/or pneumonia.

In men, infection with Chlamydia trachomatis can lead to urethritis, epididymitis, prostatitis, proctitis, or reactive arthritis. Both men and women infected with C. trachomatis may also experience conjunctivitis, pharyngitis, and lymphogranuloma venereum. Lymphogranuloma venereum (LGV), caused by distinct serovars of Chlamydia trachomatis, is a less common disease characterized by enlarged lymph nodes or severe proctocolitis.