What is Chlamydia trachomatis? Chlamydia trachomatis is a small bacterium that cannot grow outside a living cell. In this respect it resembles a virus, but it is actually a very sophisticated organism. There are two other related organisms: Chlamydia psittaci is widespread in animals and can be transmitted to humans. This organism in humans is an uncommon cause of severe pneumonia particularly when acquired from infected birds of the parrot (Psittacine) family, and occasionally of abortion following contact with infected sheep. The more recently described Chlamydia pneumoniae (also known as the TWAR agent - Taiwan Acute Respiratory, after the designations of the first two isolates), may prove to be a frequent cause of upper and lower respiratory infection transmitted from person to person by infected droplets. Which diseases does it cause? Worldwide, the most important disease caused by Chlamydia trachomatis is trachoma, one of the commonest infectious causes of blindness. In some parts of the developing world, over 90% of the population becomes infected. However, the specific strains of Chlamydia trachomatis which cause trachoma and the epidemiological conditions for its spread, are not found in the UK. In Britain, the organism often causes genital tract infection. In men, Chlamydia trachomatis is the commonest cause of non-gonococcal or (less correctly) non-specific urethritis. In women, the organism may infect both the cervix and the urethra. Epididymitis may complicate infection in men, whilst in women infection in the upper genital tract - the endometrium and the fallopian tubes, may lead to acute pelvic inflammatory disease (PID). Chlamydia trachomatis is the most frequent ...
