Initial test results show that 19 horses have tested positive for possible strangles infection at the Trackside training center in Louisville, Ky., according to information provided by Churchill Downs.

In all, 49 horses–43 Thoroughbreds and five ponies–underwent tests for the highly contagious equine bacterial disease. Twenty-four have come back negative, while six are pending, track officials said March 17.

The first case was reported the weekend of March 12. At the time, Churchill had taken precautions to confine horses in barns K and L at its training facility located about 15 minutes from the racetrack.

State veterinarian Robert Stout, DVM, and the Kentucky Department of Agriculture recommended precautionary measures so the illness could be contained to the quarantined barns. Additional tests to determine the status of each horse are scheduled, including a round of tests set for March 17