| (Brooder pneumonia, Mycotic pneumonia, Pneumomycosis) Aspergillosis is a disease, usually of the respiratory system, of chickens, turkeys, and less frequently ducklings, pigeons, canaries, geese, and many other wild and pet birds. In chickens and turkeys, the disease may be endemic on some farms; in wild birds, it appears to be sporadic, frequently affecting only an individual bird. It is usually seen in birds 7-40 days old. Etiology and Epidemiology: Aspergillus fumigatus is a cause of the disease. However, several other Aspergillus spp , as well as other genera, eg, Penicillium , may be incriminated. Chicks and poults may become infected during hatching as a result of inhaling large numbers of spores in heavily contaminated hatching machines or from contaminated litter. In older birds, infection is caused primarily by inhalation of spore-laden dust from contaminated litter or feed or dusty range areas. Clinical Findings and Lesions: Dyspnea, hyperpnea, somnolence and other signs of nervous system involvement, inappetence, emaciation, and increased thirst may be seen. The encephalitic form is most common in turkeys. In chicks or poults up to 6 wk old, the lungs are most frequently involved. Pulmonary lesions are characterized by cream-colored plaques a few millimeters to several centimeters in diameter; occasionally, mycelial masses may be seen within the air passages on gross examination.  The plaques also may be found in the syrinx, air sacs, liver, intestines, and occasionally the brain. An ocular form, in which large plaques may be expressed from the medial canthus, has been seen in chickens and turkeys. Diagnosis: The fungus can be demonstrated by culture or by microscopical examination of fresh preparations. One of the plaques is teased apart and placed on a suitable medium, usually resulting in a pure culture of the organism. Histopathological examination using a special fungus stain reveals granulomas containing mycelia. Pathogenicity of the isolate is confirmed by injecting it into the air sacs of susceptible 3-wk-old chicks. Differential diagnoses include infectious bronchitis, Newcastle disease, laryngotracheitis, and Dactylaria infection. Control: Strict adherence to sanitation procedures in the hatchery minimizes early outbreaks. Grossly contaminated eggs should not be set for incubation because they may explode and disseminate spores throughout the hatching machine. Contaminated hatchers should be fumigated with formaldehyde or thiabendazole (120-360 g/m3 ). Avoiding moldy litter or ranges serves to prevent outbreaks in older birds. Pens should be sprayed with nystatin, and all equipment cleaned and disinfected. Treatment of affected birds is considered useless. |
