Explore the recorded discovery and history of Chlamydia trachomatis, with source links and stated limits.
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.
LPSN records the basonym “Rickettsia trachomae” Busacca 1935. The epithet trachomatis derives from the Greek for a roughness and then from the eye disease trachoma, so the species name records the eye disease it was first tied to rather than the genital infections it also causes.
LPSN records Chlamydia trachomatis corrig. (Busacca 1935) Rake 1957, effectively published in the seventh edition of Bergey’s Manual of Determinative Bacteriology, and retained on the 1980 Approved Lists of Bacterial Names. LPSN lists it as the correct name and explicitly recommended for medical use. Type strain A/Har-13 / ATCC VR-571B.
These references do not identify a first person ever infected. Trachoma is an ancient disease described long before the organism was named, so the 1935 and 1957 records date scientific description and nomenclature rather than a first human case or an origin.
Source check: 2026-09-20. Educational content; independent scientific review remains pending.