Officials at Horse Haven of Tennessee, a Knoxville-based horse rescue operation, have announced the farm is under quarantine for the next five weeks after a case of strangles—a highly contagious equine disease—was diagnosed on the property.

"This is the first time since Horse Haven opened its doors to the public, that we had to resort to this drastic measure," the rescue operators said in a statement. "We would like to point out that the active case was not a new intake at our facility," the statement said. "It is possible that bacterium was carried onto Horse Haven property on a person or persons."

The organizers noted that, until the attending veterinarian gives the all clear, all public events on the property—including April’s open house and adoption day, April’s volunteer orientation, and the April trail challenge—have been canceled.

"We will operate with minimal personnel to prevent the further spread of disease," the rescue operators said