Infectious bursal disease virus, known as IBDV for short, is not known to infect people or other animals. Washington State University's animal disease lab says it has been confirmed in one flock of birds here - the first confirmed case in the United States outside of California.
The disease can kill many birds in a flock and hits young birds especially. It can also suppress their immune system, making them more susceptible to secondary diseases.
Researchers say wild birds, such as healthy ducks and quail, have been found to be naturally infected, but it doesn't appear that they play any major role in the spread of disease to domestic poultry.
Affected birds can appear lethargic and unsteady. Experts advise that definitive diagnosis be made through post-mortem examination and testing.