As soon an animal shows symptoms, remove it from the rest of the herd and begin antibiotic treatment. Monitor the animal closely to see if it responds to treatment.
With a viral disease, rest and supportive care while the infection runs its course is the most important thing. Depending on your horse’s temperament, he may stop eating and drinking. If he stops drinking, he is setting himself up for dehydration, impaction colic, and other problems. It’s much easier to steer your horse in the right direction if you can get on top of it right away.
For any respiratory infection, a key treatment component is a rest – the lungs need time to recover.