You have worked hard all week and just when you need Mr. Ed to get away from it all, he is sick. The possibilities are influenza or flu, rhinopneumonitis or rhino, distemper or strangles, and other less common viral or bacterial diseases. The most likely is flu. Flu is an extremely common viral respiratory infection which occurs in the warmer months of the year. March through October are the most common months for flu to occur in Colorado and like climates.
Flu is extremely contagious.
It spreads by direct and indirect contact, animals touching each other or using the same water buckets or feed buckets. It also can be carried by aerosol, through the air and can spread rapidly across vast areas of country side. Since opening a veterinary practice in Grand Junction, Colorado in 1966, I have seen flu outbreaks in the spring, summer and fall every year. The symptoms can vary some, but usually include the following signs. Most mature horses in good physical condition will survive flu without any treatment as long as they are not used hard and have good dust free feed and plenty of fresh water.