Systematic Veterinary Virology

SYMPTOMS

• IBD is a disease only affecting chickens, and mainly those around 3-4 weeks old when the bursa is well developed. In younger birds the disease usually has a subclinical course.
• Diseased chickens are pale, depressed, dehydrated, anorectic, shivering, have an insecure, atactic pace and ruffled feathers. They often develop transient diarrhoea that can be white with red or green staining.
• Further there is self-inflicted vent picking. When the infection occurs earlier in life the immunosuppression becomes permanent. In other cases, it usually is transient.
•  Some birds may also show growth retardation after recovery. No disease can occur after 15-16 weeks of age when the bursa is regressed.
• The immunodeficiency caused by the virus depends on viral strains, age of the chicken and co-infection with other pathogens.