Short answers, pulled from the story.
Chlamydia is a sexually transmitted infection caused by the bacterium Chlamydia trachomatis. The organism only infects humans and can establish long-term associations inside host cells, often producing no symptoms for months or years.
At least 70% of genital chlamydia infections in women and 50% in men are asymptomatic at the time of diagnosis. The infection can linger for months or years before being discovered, allowing it to spread widely without detection.
Untreated chlamydia can cause pelvic inflammatory disease in women, leading to chronic pelvic pain, infertility, or ectopic pregnancy. In men it can cause epididymitis and, in rare cases, sterility. Chlamydia can also trigger reactive arthritis, and women infected with chlamydia are up to five times more likely to acquire HIV if exposed.
Nucleic acid amplification tests (NAATs) are the standard diagnostic method and carry an estimated sensitivity of approximately 90% and specificity of approximately 99%. Testing can be done on urine or swabs from the cervix, vagina, or urethra, with rectal or mouth swabs needed to diagnose infections in those areas.
Chlamydia is curable with antibiotics; azithromycin and doxycycline are most commonly used. Sexual partners must also be treated, infected people should avoid sex for seven days after treatment, and retesting is recommended three months later to check for reinfection.
Trachoma is a chronic conjunctivitis caused by Chlamydia trachomatis and was once the leading cause of blindness worldwide. Repeated untreated eye infections cause permanent sight damage; its share of global blindness fell from 15% in 1995 to 3.6% in 2002, and the World Health Organization now targets global elimination by 2030.