Ornithosis is an acute zoonotic chlamydia disease with a primary lesion of the lungs and the development of intoxication syndrome.
Brief historical information
The disease was first described by T. Jurgensen under the name of atypical pneumonia (1876). In 1879, D. Ritter established his connection with the infection from parrots. An outbreak of infection, the source of which became the parrots imported from Brazil, was observed in 1892 in Paris, as a result of which the disease was called “psittacosis”, i.e. psittacosis. Later it was found that not only parrots can be the source of infection, but also many other species of birds, in connection with which the disease was called ornithosis. The causative agent identified the joint venture. Bedson (1930).
The causative agent is Gram-negative immobile bacterium Chlamydia psittaci, of the genus Chlamydia of the family Chlamydiaceae, obligately parasitic in infected cells. Chlamydia have a spherical shape, are painted by Romanovsky-Giemsa in purple. They contain DNA and RNA, breed only in living cells, are cultured in tissue cultures and chicken embryos, as well as in the body of laboratory animals (on white mice). Possess thermolabile and thermostable antigen. The pathogen is resistant to freezing, inactivated when heated and under the influence of disinfectants in normal concentrations. Referred to the second group of pathogenicity.
The reservoir and sources of infection are domestic and wild birds. Currently, the causative agent of ornithosis is isolated in more than 150 species of birds. Poultry (especially ducks and turkeys), indoor birds (parrots, canaries and other small songbirds), and especially urban pigeons, whose infection varies in the range of 30-80%, have the greatest epidemiological significance. Birds secrete pathogen with feces and nasal secretions. A sick person is not an epidemiological hazard. The period of contagiousness of the source – weeks and months.
The transmission mechanism is aerosol, dust and food infection is possible.
The natural susceptibility of people is high. Post-infectious immunity is short, repeated cases of the disease are possible.
Major epidemiological signs. The disease is widespread. About 10% of all pneumonia has ornithosal nature. More often, persons who are constantly in contact with birds (employees of poultry farms, meat processing plants, golubevody, pet store workers, etc.) get sick. Domestic diseases occur throughout the year, professional – during periods of mass slaughter of poultry, the importation of new batches of birds, etc. In the case of domestic infection, sporadic diseases are more often observed, although small (family) outbreaks are also possible. Persons of middle and older age get sick mainly.
The pathogen penetrates the epithelium of the mucous membranes of all parts of the respiratory tract, including the small bronchi and alveoli. In epithelial, lymphoid and reticulohistiocytic cells, its reproduction and accumulation take place. With the destruction of the affected cells, their decay products, as well as chlamydia, bacterial toxins and waste products enter the blood. Intoxication and allergization of the body are increasing. With ornithosis, severe intoxication can lead to infectious-toxic shock. Chlamydia can penetrate into various organs and systems, primarily in the lungs, nervous, cardiovascular systems, the liver. The organs develop an inflammatory process of serous, and in cases of adherence of conditionally pathogenic flora – of a mixed nature. Pneumonia develops on the background of catarrhal tracheobronchitis and hyperplasia of peribronchial lymph nodes. Chlamydia are capable of long-term intracellular localization, which makes it possible for the disease to recur.
Incubation period. Lasts 1-3 weeks. Infection can occur in an acute or chronic form.
Acute form. It starts with a rapid increase in temperature to high numbers. Fever accompanied by chills, increased sweating, pain in muscles and joints, headache. Fever is permanent or remittent in nature and lasts from 1 to 3 weeks.
Patients complain of weakness, sore throat, sleep and appetite disturbances, constipation. Sometimes nausea and loose stools are possible.
When viewed in some patients reveal the phenomenon of conjunctivitis. Tongue thickened, lined, possible imprints of the teeth at the edges. Often in the first week of the disease is formed hepatolienal syndrome. Muffled heart sounds, noted propensity to bradycardia and lower blood pressure. Insomnia, agitation, irritability and tearfulness, in some cases – lethargy, apathy, and adynamia develop. Symptoms of irritation of the meninges may be detected ..
The first sign of lung damage – cough, dry or with mucous sputum, appears only on the 3-4th day of illness. During this period, patients can identify signs of laryngitis and tracheobronchitis. In the future, with the development of pneumonia, dyspnea is not pronounced, percussion changes in the sound above the lungs are rarely determined, with auscultation, dry rales are heard, and only in some cases, single ones – finely bubbly. However, radiological examination can reveal interstitial changes or foci of infiltrates, usually located in the lower parts of the lungs, as well as an expansion of the pulmonary roots, an increase in the pulmonary pattern, and sometimes an increase in the root lymph nodes. In the case of the admission of conditionally pathogenic flora, pneumonia can also be large-focal and lobar.
Resorption of pneumonia foci occurs slowly, asthenia persists for a long time. Sometimes full recovery occurs in 10-15 days, in other cases the disease becomes remitting with subsequent relapses. Early relapses develop after 2-4 weeks after the acute phase, late – after 3-4 months. The fate of patients with ornithosis takes a chronic course. The seldom occurring variants of the acute form of ornithosis also include cases of the disease without lung damage, occurring with moderate fever, sore throat, myalgia, and the development of the hepatolienal syndrome. Ornithosal serous meningitis, sometimes associated with pneumonia, as well as meningoencephalitis with the development of polyneuritis, paresis and paralysis (vocal folds, lower extremities) are known.
Chronic form. It develops in 10-12% of patients and occurs in the form of chronic bronchitis or lesions of other organs and systems, and may last for several years.
Generalized form of ornithosis. The disease belongs to the group of zoonotic chlamydia that develops in human infection with C. psittaci. It has etiological, epidemiological and pathogenetic characteristics common with ornithosis.
Incubation period. Varies from 1 to 3 weeks. More often, the disease begins acutely with a rapid rise in body temperature to high numbers, chills, headaches, arthralgia. Sometimes prodromal syndrome can manifest itself in the form of general weakness, loss of appetite, headache and subfebrile condition. Subsequently, high fever persists for several days, decreases lytically. Patients complain of dry mouth, thirst, nausea, loss of appetite, sleep disturbances. In most cases, from the first days of the disease arthralgia develops in the large joints of the extremities.
When examining patients note pallor of the skin (much less often short-term flushing of the face and upper body), conjunctivitis with serous discharge, vascular injection of the sclera. Muffled heart sounds, rapid pulse, labile, blood pressure is prone to a slight increase. Pathology of the respiratory system is absent. The tongue is thickly coated with white bloom, the size of the liver is enlarged, the spleen is intact. Urination is increased, diurnal diuresis is increased, the content of protein, leukocytes, cylinders increases in the urine, hypo- and isosthenuria is noted. Patients are asthenized, emotionally labile. There may be neurological symptoms in the form of tremor of the fingers, trembling of the tongue when protruding, paresthesia in the hands, neuritis of the trigeminal nerve. Characterized by the development of episcleritis on the 2nd week of illness or later. It is manifested by a burning sensation, “sand in the eyes”, pain when moving the eyeballs, sometimes by a decrease in vision. Possible changes from the fundus of the eye.
Ornithosis should be distinguished from flu, acute respiratory viral infections, various inflammatory processes in the lungs, tuberculosis, brucellosis, Q fever, infectious mononucleosis, mycoplasmosis, and in some cases from serous meningitis.
At the onset of the disease, fever with chills and sweating, sore throat, muscles and joints are characteristic. Conjunctivitis is noted, a thickened tongue with possible teeth imprints along the edges, often hepatolienal syndrome, disturbances in the emotional sphere – agitation, irritability, tearfulness. From the 3-4th day of illness, laryngitis or bronchitis, interstitial or small focal pneumonia with scanty physical data develop. If ornithosis is suspected, data from the epidemiological history are taken into account – contact with birds (employees of poultry farms, meat processing plants, golubevody, workers of pet stores, etc.).
Leukopenia or normocytosis, relative lymphocytosis and aneosinophilia are determined in the hemogram, ESR is increased or normal.
The selection of chlamydia from the blood and pathological material in a wide practice is not carried out. The basis consists of serological methods – RSK and RTGA with the formulation of reactions in paired sera, as well as ELISA.
The most effective etiotropic agents in the treatment of ornithosis and the generalized form of chlamydia are azithromycin and erythromycin in moderate therapeutic doses. It is possible to use tetracycline antibiotics. The duration of the course depends on the clinical effect. As means of pathogenetic treatment, detoxification therapy is carried out, bronchodilators are prescribed, vitamins, oxygen, symptomatic agents.
Includes accounting and analysis of the incidence of people, tracking the epizootological situation among birds, monitoring the state of their habitat and content.
They include the fight against ornithosis in poultry, the regulation of the number of pigeons, and the limitation of contact with them. An important point is the observance of veterinary and sanitary rules when importing birds from abroad, transporting and keeping birds in poultry farms and zoos. Sick birds are destroyed, the room is subjected to disinfection. The staff is provided with working clothes and disinfectants. Specific prevention is not developed.
Activities in the epidemic outbreak
Patients are hospitalized for clinical and epidemiological indications. Persons at risk of infection are prescribed medical observation for a period of 30 days. Emergency prophylaxis can be performed for 10 days with doxycycline 1 time per day, 0.2 g or tetracycline 3 times per day, 0.5 g. In the center, final disinfection is carried out with 5% solutions of chloramine, lysol, and clarified bleach solution.