Psittacosis is an infectious natural focal disease of birds, mammals and humans, characterized by an atypical pneumonia, enteritis, fibrinous peritonitis, encephalitis. The causative agent of psittacosis is bacteriology intracellular parasite – chlamydia (Chlamydia ornithosis), which is resistant to sulphonamides and sensitive to some antibiotics (tetracycline, chloramphenicol). Chlamydia in the external environment persist 2-3 weeks. Infection atriums is preferably the mucosa of the respiratory tract: infection occurs by airborne dust by rarely through food. Often the pathogen is introduced in small bronchi and bronchioles, causing bronchial inflammation. Very quickly the causative agent enters the blood, causing the symptoms of General intoxication and failure of various organs. In some cases, chlamydia penetrate into the Central nervous system, lead to the development of serous meningitis.
Reservoir and sources of infection – domestic and wild birds. Currently, the causative agent of psittacosis selected from more than 150 species of birds. The largest epidemiological significance have Pets poultry (especially ducks and turkeys), room birds (parrots, Canaries and other small songbirds), and especially pigeons, infestation which varies in the range of 30-80%. Birds shed the pathogen in faeces and nasal secret. Epidemiological sick person is not dangerous.The infectiousness of the source, weeks and months.
The mechanism of transmission – aerosol, dust and possible food ways of infection. Natural susceptibility of people is high. Postinfectious immunity is short, there are repeated cases of the disease.
The incubation period lasts 6 to 17 days (usually 8-12 days). Pneumonic form of ornithosis begin acutely: fever and symptoms of General intoxication, who were later joined by signs of defeat of respiratory organs. Most patients with temperature above 39 C, chills, severe headache, pain in the muscles of the back and limbs, weakness, may be vomiting, nosebleeds. For 2-4-th day of illness joined by signs of lung disease: dry cough, sometimes stabbing pain in the chest, 1 to 3 days begins to stand out a small amount mucous or mucous-purulent sputum, sometimes mixed with blood. Often affects the lower lobe of the lung, usually the right hand. X-ray revealed focal and segmental pneumonia. At the end of the 1st week in half of the patients increased liver and spleen.
The duration and severity of individual symptoms depend on the severity of the disease. In milder forms of toxemia moderate, and the fever lasts 2-5 days, with severe it can last up to 1 month. Fever wrong type with large daily swings in temperature, by repeated chills and sweating, sometimes wavy. Long-term (in severe forms up to 2-3 months) broken capacity for work, relapses and complications (myocarditis, thrombophlebitis). Sometimes the disease becomes chronic.
Atypical for acute psittacosis is manifested meningeal syndrome, which may occur on the background of chlamydia psittaci pneumonia (meningomyelocele), or serous meningitis with a long period. Psittacosis sometimes occurs as an acute febrile illness with severe toxicity, enlarged liver and spleen, but no signs of lung affection.