The infection in poultry usually occurs from ingestion of contaminated food and water. The lesions develop in spleen, liver and intestines; less frequently the lungs are also involved. The liver and spleen become enlarged and contain greyish nodules. Lesions in the intestines are relatively large. Mucous membrane shows ulceration.
The diagnosis is done by tuberculin test. The control measures comprise destruction of all birds positive to tuberculin and disinfection of premises.