ABSTRACT
Chlamydia trachomatis is a human pathogen which can cause sexually transmitted urogenital infections, neonatal conjunctivitis and pneumonia, ocular trachoma, and urogenital infection associated with lymphadenopathy and lymphadenitis (LGV). C. trachomatis contains two human biological variants (biovars): trachoma and LGV. Fifteen serologic variants (serovars) have been identified in trachoma biovar. C. trachomatis is characterized by a biphasic developmental cycle: metabolically inert infectious elementary body (EB) and a larger noninfectious reticulate body (RB). C. trachomatis (serovars D–K) is sexually transmitted in the EB form; ocular infection of C. trachomatis (serovars A–C) can be transmitted from eye-to-eye by fingers, shared cloths or towels, by eye-seeking flies, and by droplets. Both innate and adaptive immune responses are induced during C. trachomatis infection, but they are usually inefficient at controlling the infection. This may lead to the partial clearance of the pathogen from the body resulting in bacterial persistence, chronic inflammation and tissue damage. The clinical symptoms and nucleic acid amplification tests (NAATs) are used for diagnosis. Disease management is based on treatment with antibiotics such as doxycycline and azithromycin, sanitary and behavioral measures. Several vaccine prototypes are under development.
