Written by: Dr. Jacquie Jacob, University of Kentucky
Infectious bursal disease (IBD) is a highly contagious virus that affects chickens. The bursa is important in the development of the chicken immune system. If the bursa is damaged by IBD, the immune system does not function properly.
The virus is spread by chicken-to-chicken interaction as well as by contact with contaminated clothing or equipment. The virus is shed in poultry droppings and can be spread on dust particles in the air. Alternative names for the disease include
Chicks less than three weeks old do not typically show clinical signs of this disease, but their immune systems can nonetheless be adversely affected, and they are not able to fight off the disease. For chickens older than three weeks, there is typically a rapid onset of symptoms including the following:
There is no specific treatment for IBD. Surviving chicks remain unthrifty and are more susceptible to secondary infections because of their suppressed immune systems.
A vaccine is available for this disease, but it must be used carefully. When the vaccine is administered correctly, chickens can develop effective immunity. Dead birds can also be a source of the virus, so carcasses of infected birds should be incinerated.