Medical expert of the article
New publications
Chlamydia psittaci (Chlamydia psittaci)
Last reviewed: 04.07.2025
All iLive content is medically reviewed or fact checked to ensure as much factual accuracy as possible.
We have strict sourcing guidelines and only link to reputable media sites, academic research institutions and, whenever possible, medically peer reviewed studies. Note that the numbers in parentheses ([1], [2], etc.) are clickable links to these studies.
If you feel that any of our content is inaccurate, out-of-date, or otherwise questionable, please select it and press Ctrl + Enter.
Chlamydia psittaci ( Chlamydia psittaci) causes anthropozoonotic diseases that develop as a result of human infection through professional, and less commonly, household contact with animals and birds.
Ornithosis is a disease characterized by primary damage to the respiratory organs, as well as the nervous system, parenchymatous organs, with symptoms of general intoxication.
The pathogen was discovered in 1875 by T. Jurgens. The disease caused by Chlamydia psittaci was called "psittacosis" (from the Greek psittakos - parrot), since it arose after contact with parrots. However, it was later noted that one can become infected not only from parrots, but also from other birds, and the disease was called "ornithosis" (from the Latin ornis - bird).
[ Pathogenesis and symptoms of ornithosis
The entry gate for the pathogen is the mucous membranes of the respiratory tract. The pathogen multiplies in the epithelium of the bronchial tree, in the alveolar epithelium, and in macrophages. Inflammation develops, cells are destroyed, bacteremia, toxinemia, allergization of the macroorganism, and damage to the parenchymatous organs occur. In the clinical picture of ornithosis, the symptoms of damage to the bronchi and lungs are of primary importance. Complications arise from the cardiovascular (thrombophlebitis, myocarditis), central nervous system, etc. A generalized form of chlamydial infection is possible.
Immunity is non-sterile, predominantly cellular. Repeated diseases are possible. The bacterium is capable of persisting in the respiratory organs after clinical recovery. Hypersensitivity to the pathogen's antigens, which are detected by intradermal tests, may persist for a long time.
Epidemiology of psittacosis
The source of infection are wild, domestic and ornamental birds - infected or asymptomatic carriers. Infection is also possible from ectoparasites of birds and rodents. The disease is very rarely transmitted from person to person.
The mechanism of infection is respiratory, the routes of infection are airborne dust and airborne droplets when inhaling dust contaminated with the secretions of sick birds.
People are highly susceptible to ornithosis. The disease is professional in nature - people working on poultry farms and owners of ornamental birds are more likely to get sick.