Researchers Find Internal "Hiding Place" of New Turkey Ailment

By Jim De Quattro
June 25, 1999

A new disease has been killing flocks of turkeys in the Southeast since 1995. Now, scientists with USDA's Agricultural Research Service and North Carolina State University have identified one of its hiding places--and its first internal target: the turkey's disease-fighting lymph tissue.

Poult Enteritis Mortality Syndrome, or PEMS, weakens the turkey's immune system, leaving it highly vulnerable to bacterial and parasitic infections. But the new discovery could lead to better understanding and--eventually--treatment and prevention.

PEMS outbreaks in the Southeast have cost the turkey industry millions of dollars in losses annually. Other outbreaks have been reported in Texas and Virginia. PEMS-related mortality ranges between 25 to 96 percent in affected flocks. Birds that recover reach only about 40 percent of typical market weight.

The syndrome is apparently a deadly combination of viruses. Specific causative agents have not yet been identified, according to microbiologist Stacey L. Schultz-Cherry at the ARS Southeast Poultry Research Laboratory in Athens, Ga. But she and ARS colleagues, collaborating with NCSU veterinarian John Barnes in Raleigh, N.C., found that PEMS strikes first in the thymus, or lymphoid glands of turkeys. Very few viruses are known to grow in the thymus. The ability of a virus to infect the thymus is a special concern because it is a designated disease fighter.

The researchers recently isolated one virus from the thymus of a turkey sick with PEMS. They are attempting to identify it and determine its role in PEMS. The research will aid in developing diagnostic tools and treatments to prevent future outbreaks.

Increased vigilance on turkey farms has decreased the incidence of PEMS, But before scientists can develop effective treatments, they need to learn much more about the causative agent or agents and their effects on the turkey's immune response.

Schultz-Cherry is scheduled to present detailed findings on July 13 at the American Veterinary Association Meeting in New Orleans. ARS is the U.S. Department of Agriculture's chief scientific wing.

Scientific contact: Stacey Schultz-Cherry or David Swayne, ARS Southeast Poultry Research Laboratory, Athens, Ga., phone (706) 546-3432, fax (706) 546-3161, sschultzcherry@sprynet.com or dswayne@arches.uga.edu.