Aspergillosis of birds
The aspergillosis is a disease of birds caused by fungi , especially from the genus Aspergillus , is caused. It is the most common respiratory disease in captive parrot birds. Aspergillosis is a factor disease that is favored by poor keeping (especially low air humidity ) and feeding errors (feed contaminated with fungal spores, vitamin A deficiency) as well as stress (transport, excessive stocking). The disease is chronic, but mostly an acute flare-up with breathing problems is noticeable. The treatment is carried out with antimycotics and the removal of the factors that favor the disease.
Cause of illness
Aspergillosis is caused by molds of the genus Aspergillus , more rarely also representatives of the genera Mucor , Absidia (especially Absidia corymbifera ), Rhizopus (especially Rhizopus oryzae ) and Penicillium .
Aspergillosis is a factor illness : incorrect keeping (especially low air humidity ) and feeding errors (feed contaminated with fungal spores, vitamin A deficiency) as well as stress (transport, excessively high levels) play an important role in tackling the infection.
Signs of illness
Aspergillosis develops slowly. The early symptoms such as general weakness, decreased stamina when flying, drowsiness, fatigue and weight loss are often overlooked by the pet owner. The molds mainly affect the airways. The growth and the resulting inflammatory reaction often lead to a narrowing of the airways with breathing problems . In addition, toxins are released into the body that can damage the liver , gastrointestinal tract and nervous system . Finally, secondary bacterial infections can occur. The clinical picture is therefore very diverse. In addition to respiratory symptoms such as abnormal breathing noises , “cheek blisters”, coughing and sneezing, voice loss or voice changes (fungal growth in the vocal head ), diarrhea and central nervous seizures can also occur.
Although the disease often develops over a period of years, symptoms can be acute if the fungal turf dissolves and obstructs the airways.
Diagnosis
As the aspergillosis usually develops insidiously and the symptoms are unspecific, the clinical examination provides at most suspicious factors. A clear indication is only given if fungal tears appear on the nostrils. Swab samples from the nose, throat, or windpipe rarely give clear results.
The X-ray examination mainly shows the chronic changes in the lungs and air sacs (air sac mycosis). In the case of the disease, the border between the posterior chest air sac and the abdominal air sac can be made radiologically visible. If the airbag openings are narrowed, the airbags can be overstretched (" air trapping "). In addition, "mushroom bridges" in the form of braces, similar to the crescent moon signs in human aspergillosis , can be represented. Diffuse shadows can appear on the lungs, and focal points in the case of fungal granulomas . The toxins can also lead to an enlargement of the heart , liver and kidneys , which can be demonstrated radiologically . In unstable patients, the X-ray examination sometimes cannot be carried out because there is a risk that the animals will die during it. The absence of radiographically detectable changes does not reliably rule out aspergillosis.
The endoscopic examination of the air sacs and the lungs gives the most reliable results. However, it is only possible under anesthesia and therefore not always feasible in severely weakened patients. This reveals opaque air sac walls and possibly granulomas.
Blood tests hardly give any indications, the serological detection of antibodies has not yet been sufficiently established.
treatment
Itraconazole , terbinafine and voriconazole are used systemically as antimycotics . In Germany, a drug based on itraconazole is approved for pet birds (trade name Fungitraxx ), but the active ingredient is poorly tolerated by some African parrots (African gray parrot , black-headed parrot ). If the symptoms are severe, amphotericin B is also indicated. For prophylaxis, treatment of mild cases and chronic diseases, enilconazole can be used by inhalation. the treatment is usually carried out for seven weeks, with regular x-ray and blood tests being advisable.
The elimination of feeding and husbandry errors is essential. Vitamin A can be given as a support.
