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. Instances of severe outbreaks are usually seen
in birds 7–40 days old. (Also see Fungal Infections:
Aspergillosis and see Pet Birds: Aspergillosis.) Etiology and
Epidemiology Aspergillus fumigatus is a common cause of the
disease. However, several other Aspergillus spp may be
incriminated. High mortality rates are seen in chicks and poults
that inhale large numbers of spores during hatching in
contaminated incubators or when placed on mold-bearing litter.
In older birds, infection is caused primarily by inhalation of
sporeladen dust from contaminated litter or feed or dusty range
areas. Morbidity can be underestimated in finishing flocks until
slaughter inspection reveals pulmonary l