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Ornithosis (psittacosis)
Last reviewed: 04.07.2025

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Ornithosis (ornithosis; syn. psittacosis ) is a zoonotic natural-anthropurgic infectious disease with an aerosol mechanism of transmission of the pathogen, characterized by fever, intoxication, damage to the lungs, nervous system, and hepatosplenic syndrome.
ICD-10 code
A70. Ornithosis.
Causes of ornithosis
The causative agent of ornithosis is Chlamydophila psittaci, genus Chlamidia, family Chlamidiaceae, obligate intracellular parasite. It reproduces by binary fission in the cytoplasm of affected cells. Chlamydiae are capable of forming L-forms. They have heat-labile antigens. Pathogenicity factors are surface exotoxins and LPS (endotoxin). They are cultivated in tissue cultures and on chicken embryos. They are highly resistant in the environment. Sensitive to disinfectants.
The reservoir and source of the pathogen are various species of wild synanthropic, ornamental and domestic birds, in which ornithosis occurs as a carrier; or acute intestinal infection. The mechanism of transmission of the pathogen is aerosol. The route of transmission is airborne dust. The fecal-oral mechanism is possible: by food transmission of infection (up to 10% of cases). Ornithosis is a widespread disease, recorded as sporadic cases and group industrial or family outbreaks. It has been established that 10-20% of community-acquired pneumonias have ornithosis etiology. Birds of the parrot and pigeon families are of the greatest epidemiological significance.
Ornithosis - Causes and Pathogenesis
Symptoms of ornithosis
The incubation period for ornithosis is from 5 to 30 days, most often 8-12 days. In the pneumonic form, the disease usually begins acutely: with chills, an increase in body temperature to 38-40 C, severe weakness, headache, muscle and joint pain. The temperature reaches its maximum on the 2nd-4th day of the disease. The fever is remittent in nature, and without treatment, the temperature lytically decreases on the 2nd-4th week of the disease. In severe cases, a constant fever is possible. From the 2nd-3rd day of the disease, a dry, sometimes paroxysmal cough appears. On the 3rd-4th day, the cough becomes productive. The sputum is mucopurulent, sometimes with streaks of blood. Pain when breathing, shortness of breath are possible. The main symptoms during this period are laryngotracheitis and tracheobronchitis. On the 5th-7th day, physical signs of lung damage are determined: shortening of percussion sound, weakened or harsh breathing, mild crepitation or fine bubbling rales in the lower parts of the lungs.
Diagnosis of ornithosis
A preliminary diagnosis of the pneumonic form of ornithosis is established based on clinical and epidemiological data: a picture of atypical pneumonia (clinically, radiologically), the absence of an acute inflammatory reaction of the blood, high ESR, contact with birds, and sometimes group morbidity. The diagnosis is confirmed by the methods listed below.
- By the method of bacterioscopy of sputum smears stained according to Romanovsky-Giemsa.
- Chlamydia antigens are determined using RIF or RNIF using antibodies labeled with fluorochrome.
- Biological method - by infecting chicken embryos or indicator cells with the material being studied.
Treatment of psittacosis
Bed rest or semi-bed rest. No specific diet required, table No. 13.
Etiotropic therapy: doxycycline 0.1 g twice a day until the third day of normal temperature, but not less than 10 days. In case of slow regression of the process in the lungs - until the 10th day of normal temperature (up to 3 weeks). Alternative drugs - erythromycin at a dose of 0.5 g 3-4 times a day according to a similar scheme and azithromycin - 0.5 g / day once, up to 10-12 days.
Pathogenetic therapy: bronchodilators, expectorants, during the convalescence period - physiotherapy.
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