An unknown equine illness has forced the quarantine of one barn at Hawthorne Race Course, located in Cicery/Stickney, Ill., according to track assistant general manager Jim Miller.

"We were informed yesterday by our state vet at Hawthorne that two horses were having respiratory issues in Barn A," Miller told TheHorse.com via e-mail Oct. 15. "Because it was a Sunday and testing labs aren’t open, she requested that as a precaution we quarantine that barn only until the samples could be tested and returned."

He noted that the veterinarian relayed that no other horses on Hawthorne’s backstretch have shown any clinical signs.

"We just want to be cautious in the case that it is something that can spread and isolate it only to that barn," Miller wrote. "It doesn’t affect any of our horses shipping in or shipping out aside from that barn, and we will know more once the test results return, hopefully on Wednesday