Read condition-specific symptoms and clinical context for Chlamydia trachomatis. An obligate intracellular bacterium behind both the world’s leading infectious cause of blindness and its most reported bacterial STI.
PHAC describes C. trachomatis as a nonmotile, Gram-negative, obligate intracellular pathogen around 0.3 to 1 micrometre in diameter with a biphasic lifecycle: an elementary body for extracellular survival and a reticulate body for intracellular replication. Eighteen serovars are recognised — four causing trachoma, five causing lymphogranuloma venereum and the remainder causing other sexually transmitted infections — so one species name covers strikingly different diseases. WHO estimated 129 million new chlamydia infections worldwide in 2020. Separately, WHO reports trachoma as a public health problem in at least part of 29 countries, with about 1.9 million people blind or visually impaired from it.
CDC lists symptoms for women and men while stressing that the infection frequently presents without noticeable signs. PHAC gives an incubation period of 7 to 14 days for genital infections.
Possible symptoms: Abnormal vaginal discharge; Burning sensation when peeing; Discharge from the penis; Testicular pain.
CDC states that untreated chlamydia in women may lead to pelvic inflammatory disease, potentially causing scarring of fallopian tubes, ectopic pregnancy or infertility, and that the condition is curable with appropriate antibiotic therapy. Testing and treatment are clinical decisions.
PHAC describes trachoma as acute inflammation of the epithelium of the eye caused by four of the eighteen serovars, with chronic reinfection causing blindness in endemic areas. WHO reports it as a public health problem in at least part of 29 countries.
Possible symptoms: Inflammation of the surface of the eye; Scarring from repeated infection; Vision loss in endemic areas.
WHO reports that in 2025, 47.4 million people were treated with antibiotics and 98,829 people received surgical treatment, and that 33 countries have been validated as having eliminated trachoma as a public health problem. These are programme figures, not individual advice.
PHAC states that infections may be asymptomatic, and CDC that chlamydia often has no symptoms.
The bundled sources give no symptom list for asymptomatic infection, and none is invented here. CDC states that women remain at particular risk because the infection can damage reproductive organs silently, so absence of symptoms is not absence of consequence. This is silent infection with an obligate human pathogen — PHAC gives the host range as humans only — rather than harmless carriage of a normal resident.
Asymptomatic infection is found by testing rather than by symptoms. Screening recommendations are clinical guidance and are not reproduced here.
Source check: 2026-09-20. Educational content; independent scientific review remains pending.