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 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.Clinical signs of strangles are fever, discharge from the nostrils, swelling in the lymph glands, and loss of appetite. A majority of horses recover from the disease but a period of isolation from other horses is necessary. Strangles is caused by Streptococcus equi. "It's no surprise, given that a horse infected with strangles had been identified in that population, that other horses in the population in the quarantined barns have tested positive for the infection," Stout said in a release from the track. "The good news is that the initial case of strangles was identified early, and that measures to contain the ailment to the quarantined barns appear to have been effective."The Kentucky Department of Agriculture and Churchill Downs have worked very closely in the effort to prevent the spread of this ailment, and we will continue to monitor the situation closely in the days to come."Horses in the quarantined barns have been isolated from the general population of nearly 500 horses at Trackside. Alternate training hours have been scheduled for those horses. The general population trains each day from 11 a.m-2 p.m. EST, while the horses in the quarantined barns are permitted to train each day from 2-3 p.m. Individuals who come in contact with the horses are required to undergo bio-security measures when they enter and leave the barns.Horses that again return positive results in the tests being conducted March 17 will be moved off the grounds to another quarantine location. Those horses could be moved to a location of a trainer's choosing or to Ellis Park in Henderson, Ky., which currently has no horses on its grounds and has been offered by owner Churchill Downs Inc. as an option for horses that must be moved from Trackside.Horses that return negative results from the second round of tests will be moved to another barn at Trackside. Barns K and L will then be cleaned and disinfected and that process will be repeated in 10 days.A third round of tests will be scheduled for all of the horses within seven to 10 days. Any horses that remain at Trackside that again test negative for infection will be released from quarantine and allowed to rejoin the general horse population. Before being released from quarantine, each horse will be required to undergo an endoscopic examination of the guttural pouches to ensure there is no infection.One of the horses that returned an inconclusive test on the first round was a pony stabled at Churchill Downs, which opened its barn area March 11. As a precaution, that pony and two stabled in the same barn were moved from the grounds.Stout said the horse displayed no symptoms of strangles and, even if the horse turns out to be infected, the risk of transmission to the horse population at Churchill Downs is small.Some of the horses based at Trackside race at Turfway Park in the winter. Turfway required a clean bill of health on all ship-ins about a week ago.