Aspergillus

PATHOLOGY DESCRIPTION

Aspergillus is a mould which requires only warmth, moisture and organic material to proliferate. Its requirements are so modest that these fungi can be found everywhere in the environment, and its spores may disseminate over a large distances.

Aspergillosis is a disease 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.

 

Age

 

Symptoms

 

Embryos

Decrease of egg hatchability. Mortality increase at about 16 days of incubation, as a result of spores entering the egg via pores or hairline cracks

 

Newly hatched chicks

Respiratory signs (dyspnoea, rapid breathing and stretched necks)and nervous signs (difficulty to walk); high mortality in the first ten days after hatching and for surviving chicks, growth is not optimal

 

Broilers from 4-5 weeks of age

age 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 week, the lungs are most frequently involved.

 

Breeders

When feed is contaminated with aflatoxin, the mycotoxines produced by Aspergillus, this may lead to immunosuppression, a drop in egg production and reduced fertility/hatchability of the eggs

Pulmonary lesions are characterized by cream-colored plaques. The plaques also may be found in the syrinx, air sacs, liver, intestines, and occasionally the brain. An ocular form has been seen in chickens and turkeys. Aspergillus fumigatus is a common cause of the disease. However, several other Aspergillus spp may be incriminated.