WOOSTER, Ohio - Research on a virus that contributes to the development of poult enteritis and mortality syndrome (PEMS) of turkeys may shed new light on how the illness spreads and what can be done to control it.
Ohio State University researchers Mo Saif and Yuxin Tang of the Ohio Agricultural Research and Development Center's Food Animal Health Research Program received a $30,000 U.S. Poultry and Egg Association grant to study the astrovirus. Research has found that the virus, which attacks the immune system of young turkey poults, is responsible for the development of PEMS, an emerging disease that causes high mortality and severe economic losses to the poultry industry.
Saif said the astrovirus was first detected in turkeys in the 1980s, but is believed to have undergone several mutational changes since then that have allowed it to become a contributing factor in PEMS development.
"When we first began studying PEMS in turkeys we didn't think it was the astrovirus that was causing the symptoms," said Saif. "We thought it was something completely different." Saif said that the astrovirus first began as an enteric or gastrointestinal disease but has undergone changes that enable it to enter the blood stream and lymphatic system. "Something had to have changed at the molecular level that has made the virus capable of getting out of the intestinal tract and into the general circulation," he said.
The researchers will compare the astrovirus of the 1980s with the present-day astrovirus in the hope of discovering what molecular changes the virus has undergone. The goal of the research is to find out how the astrovirus spreads and develop ways to control it, thus controlling PEMS. Currently no vaccines are available to protect turkey flocks against the illness.
PEMS was first diagnosed in 1991 in North Carolina. Since then it has spread to other states such as South Carolina, Texas, Virginia and Indiana and has cost the poultry industry over $34 million in losses. The disease, which attacks poults age two to four weeks, can cause a mortality rate as high as 70 percent. PEMS weakens the immune system, leaving turkeys highly susceptible to bacterial and parasitic infections. Those birds that survive become stunted in growth. That is, the turkey no longer gains weight despite the amount of feed it consumes.
So far, PEMS has not been found in Ohio.