Psittacosis is an infectious disease caused by the pathogen Chlamydia psittaci, this condition occurs especially among certain populations of birds, the infection can be transmitted to the human host, if the patient has high fever, signs of impaired lung (pneumonitis) and and a number of systemic manifestations, in other situations, a similar disease manifestation dress influenza infection. The name “ornithosis” may be used to describe some forms of infectious diseases transmitted from birds to humans, while the notion of “psittacosis” means all forms of disease that can occur in a human host, after contact with certain diseased birds.
Pathogen Chlamydia psittaci is able to infect many species of birds, infection occurs most frequently among species of parrots, as well as those of pigeons, ducks or turkeys. Psittacosis mostly affects workers in stores that sell live animals, poultry workers, workers who handle animal impaierea, veterinarians, zoological gardens and ingrijotorii. In recent decades, outbreaks of psittacosis have been reported among people who worked in derivatives processing plants. Also, an increased incidence of this disease has been reported on the territory of England, where many families dwarf parrots kept in house.
Infectious pathogen was detected in nasal secretions of birds in the stool, but in certain tissues or the feathers, for some birds, the disease can be fatal, but most often is observed occurrence of minor signs of illness – letergaie, anorexia, bristly feathers, most infected birds remain asymptomatic, even after complete healing, some bird species will continue to spread the pathogen over a period of several months.
Infection can be transmitted to human hosts, by air, much less have been reported cases where infection was instilled after bird bites, for the disease, even infectious contact a few minutes spent in an environment previously contaminated, it may be enough, it goes without saying that the risk of infection is much higher in symptomatic contact with birds, human disease severity could not be correlated with the duration of contact while infectious.
There have been reported cases of illness caused by infection with a pathogen that causes psittacosis similar, these cases have occurred in some hospital units, such virulent strains involved proved more aggressive than Chlamydia psittaci in some cases generating even fatal infections. Fortunately, there were no reported cases of psittacosis, which have occurred after consumption of meat from a bird infected with the pathogen Chlamydia psittaci.
Pathogenesis and causes
Human host becomes ill after pathogen penetration through the airways of the upper airway, Chlamydia psittaci is spread by blood flow occurs in the alveoli and lung, liver and spleen. Thus, it is unlikely to be realized an invasion of lung tissue by direct extension from the upper airway, but rather by pathogen spread via blood. Subsequently generates a local inflammatory response, resulted in increased numbers of lymphocytes in the alveoli, but also perialveolara region.
Pulmonary alveolar walls presents as thickened, swollen, necrotic and sometimes even with hemorrhagic foci, alveolar spaces of the lung affected regions will be filled with a fluid containing erythrocytes and lymphocytes. Characteristic of psittacosis is microscopic identification of macrophages with cytoplasmic inclusions. Regarding repirator epithelium of the bronchi and bronchioles, it remains mostly unaltered.
Signs and symptoms
Psittacosis is quite variable clinical course, disease icubatie the average is about 10 days incubation period can sometimes even exceed two weeks. The condition starts suddenly with a high fever (over 40 ° C) and chills, in other cases the onset is gradual, ascending fever within a few days (3-4 days). The patient shows severe cephalic pain (severe headache) – it is a pain to diffuse character, which generates severe discomfort the patient, while at the same time, the main symptom of illness.
Respiratory impairment imply the occurrence of dry cough (dry cough), and thereafter as the disease progresses, the cough may change its character and become productive (patient remove small amounts of sputum, mucous or bloody character). Coughing can accompany febrile rise since the onset or can occur within a few days of fever, in very rare cases, the patient will present with chest pain pleuretic character, pleural effusion (fluid between the layers of the pleura disease, which impede the respiratory movements), or “pleural friction rub,” performed notified when pulmonary auscultation. Signs of pericarditis and myocarditis may accompany pulmonary manifestations. Frequency of respiratory movements may be slightly higher.
Severe forms of the disease, will be accompanied by pronounced dyspnea (difficulty in making respiratory movements) and cyanosis of the skin, has found that very often the physical signs of pneumonia are not consistent with radiological changes noticeable, clinical signs suggestive of pneumonia may lacking or sibilant rales patient shows discrete, identifiable by listening with a stethoscope. With the evolution of the disease, respiratory rales will increase and will be more easily detected when pulmonary auscultation is performed. Signs suggestive of pulmonary condensation process (as in true bacterial pneumonia) are often absent.
Often, the patient may experience pain in the neck and signs of pharyngitis, and lymphadenopathy (enlargement of the lymph nodes) in the neck, one quarter of patients with psittacosis, will present early epistaxis (bleeding from the nose) with the same frequency can be found and this fotofobiei (patient avoid bright light, it produces discomfort).
Back and neck muscles may be affected, patients having pain at this level, and increased muscle spasm or stiffness, muscle spasticity neck and photophobia, can guide the clinician wrong, the diagnosis of meningitis (viral or bacterial meningeal system that “wraps” the central nervous system structures). Other signs suggestive of neuronal damage: lethargy, depression, psychomotor agitation, and insomnia, delirium and stupor occurs most often after the first seven days of serious disease evolution, if the patient is comatose, when brought to the doctor, diagnosis of psittacosis can be easily overlooked.
Of digestive manifestations have been reported following symptoms: abdominal pain, nausea, vomiting and diarrhea late, there may be constipation or abdominal distension (considered as late gastrointestinal complications), when the liver is severely affected, the patient will present jaundice (discoloration yellow skin and mucosal) skin level, there may be a number of injuries eruptive macular appearance, similar lesions occur if tifode fever.
Individuals who do not have cough (dry or productive) or other signs suggestive of an impaired respiratory system are often diagnosed with “fever of unknown origin” (FUO) a febrile state though that patient is quite emphasized, seen in peripheral arterial pulse is weak. Psittacosis can be frequently accompanied by splenomegaly (enlargement of the spleen), although jaundice is rarely reported in these patients, hepatomegaly occurs more frequently, and most often painless.
During convalescence, the infection may be followed by the appearance of thrombophlebitis, serious complication that shows the danger of heart lung (pulmonary infarction is due to mobilization of curd, which will confine the pulmonary circulation, where it will produce certain territories vascular infarction, pulmonary infarction is most often a fatal complication).
If the disease is not treated properly, the fever may persist (becoming recurrence) even for a period of 90 days, during which respiratory symptoms will gradually decrease in intensity. Been statistically shown that psittacosis transmitted from parrots with long tail, evolved much more severe compared to the same human host transmitted disease by poultry or by pigeons. In very rare cases, the infection may recur, as cardiac complication, patients can develop endocarditis with negative blood cultures (pathogen C. psittaci can not be detected in the blood) have been reported rarely supraifectii bacterial and immunity installed after the acute episode of disease, retained over a long period.
Thoracic radiographs made in this disease, no specific signs, can be determined unorganized and homogeneous infiltrative lesions, diffuse wedge-shaped opacities or small nodular lesions (miliary lesions, similar to those of miliary tuberculosis). In the early stages of the disease can be detected a slight leuzocitoza (increased white blood cell count), leukocytosis is accentuated in the convalescent phase of the disease. Erythrocyte sedimentation rate (ESR, non-specific marker, which reveals the presence of an inflammatory or infectious phenomenon in the body) is kept within normal limits. Although the patient has hepatomegaly (enlargement of the liver), liver transaminases are often only slightly elevated (a sign of destruction hepatocytes).
Positive diagnosis is established after isolation or pathogen, or by serological methods, although the pathogen is often difficult to isolate, it is present in the early phase of the disease, but blood and secretions from the bronchial mucosa, unfortunately, involve risks manipulation of this pathogen, are considerable, and therefore many of microbiology laboratories, not realizing cultures for Chlamydia psittaci.
Is much easier serological diagnosis, which involves detection of specific antibodies in plasma directed against this pathogen, it is recommended that serology psittacosis to be performed both in the acute phase of the disease, and during the convalenscenta it. Immunofluorescence test to detect between infections caused by different species of Chlamydia (diagnostic errors can sometimes be induced by the presence of common antigens of these species). If treatment is started quickly with tetracycline, yielding a delay in the production of specific antibodies in convalescent period of the disease.
Also, to assess positive diagnosis is very important is possible infectious contact with certain species that carries the pathogen contacts made in recent history that individual. Of lung diseases that can be confused with psittacosis, and that should be excluded in time of the differential diagnosis be as follows: Mycoplasma pneumonia or pneumonia with C. pneumoniae, Legionnaires’ disease, of viral pneumonia, Q fever, coccidioidomycosis, tuberculosis, neterovirusuri infections, various types of lung cancer that can cause bronchial obstruction, and certain forms of frank lobar pneumonia (bacterial etiology).
Note that in the early stages of the disease, before the appearance of signs and symptoms of pneumonia, psittacosis can be confused with influenza infections, typhoid fever, miliary tuberculosis or infectious mononucleosis.
Of psittacosis treatment of choice is the administration of tetracycline at a dose of 2 grams / 24 hours in four divided doses, usually within 48 hours after initiation of this therapy, fever and respiratory symptoms will diminish considerably. It is recommended that therapy be extended for a period of about two weeks, this in order to avoid relapse, treatment should not be discontinued immediately after resolution of fever.
If the disease is severe with strong manifestations and noisy, it is recommended that the patient be hospitalized and treated in an intensive care unit. If the patient is allergic to tetracycline, it can be replaced with the administration of erythromycin. Unfortunately, it turned out that sulfonamides (exmpl. Trimethoprim) are not effective against pathogen Chlamydia psittaci.