The New Jersey Department of Agriculture’s Division of Animal Health has issued a quarantine at the Mid-Atlantic Veterinary Clinic in Ringoes, Hunterdon County, after a horse recovering from surgery there tested positive for the equine herpes virus.

The horse, which had been at Monmouth Park before a quarantine was established at the track on Oct. 27, went to Mid-Atlantic for colic surgery. Mid-Atlantic tested the horse for EHV on Oct. 23 after hearing about concerns at the racetrack, and the results were negative. However, a second test taken earlier this week turned up a positive result.

Consequently, the department began efforts to identify all horses that came into contact with the horse in question and any horses those horses contacted. In all, those “trace back” and “trace forward” measures identified 36 horses that were then tested for EHV.

“This case in Ringoes shows the vital importance of quarantines for diseases like equine herpes,” said New Jersey Secretary of Agriculture Charles M. Kuperus. “Just one horse that left Monmouth Park before the quarantine was imposed there has now created the necessity for tests of 36 others. Multiply that by the more than 1,000 horses at the racetrack and you can see how diseases like this can spread exponentially unless quarantine measures are taken