Infectious Bursal Disease in Poultry

Small and Backyard Flocks May 05, 2015 Print Friendly and PDF

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

  • gumboro disease,
  • infectious bursitis, and
  • infectious avian nephrosis.

Clinical Signs

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:

  • A sudden drop in feed and water consumption
  • Watery droppings that soil the feathers around the vent, leading to vent pecking
  • Feathers that appear ruffled 
  • Listlessness
  • Severe prostration and incoordination


There is no specific treatment for IBD. Surviving chicks remain unthrifty and are more susceptible to secondary infections because of their suppressed immune systems.

Prevention and Control

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.

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This work is supported by the USDA National Institute of Food and Agriculture, New Technologies for Ag Extension project.