JUST TO BE SAFE
Isolate your horse from others if the signs point toward a contagious disease such as strangles or a respiratory infection. Place him in his stall or in a small turnout where he is at least 10 feet away from any other horses— far enough to avoid nose-tonose contact—at least until the veterinarian arrives to confirm the diagnosis. You’ll also want to take measures against spreading any potential infection yourself, on your hands or clothes. If you need to handle other horses while you wait for the veterinarian, wash or sanitize your hands; ideally, you’d change your clothes, too, or at least put on a coverall.