Can You Ride Your Horse Through a Flu?

You wake up after having a fitful night, coughing, wheezing and constantly grabbing for that next tissue. Your chest feels it's in a vice, you can't eat and you've got the blues. What you really have is the flu, and when your horse has it, he doesn't feel any better.

With many major horse shows and competitions taking place during the next two months, the likelihood your horse will contract the flu--if you're one of those traveling--is fairly high. Influenza is a virus and is very contagious in horses. The flu in horses is caused by two distinct strains of influenza virus. Symptoms include inflammation of the nasal passages and throat, fever, coughing, wheezing, lack of appetite and depression. Because the flu is a virus, there is little that can be done to cure it, other than to treat the symptoms and increase the comfort level of its victim. However, when your horse also happens to be a competition animal and an excellent athlete, it's difficult to wait for a flu to run its course.

Influenza virus infections are common among young horses in training, and outbreaks of the virus occur at least annually in most horse populations. In a study conducted at The Ohio State University to determine the effects of exercise on horses infected with influenza as compared with infected horses given stall rest (under guidelines of the OSU Animal Care and Use Committee), it was concluded that while the exercised horses did not have the virus any longer than those given stall rest, the symptoms were definitely exacerbated by exercise. Exercised horses were worked on a treadmill five days a week at six miles per hour.

In the study, all the horses exhibited signs of the virus within 36 hours of infection, including fever, coughing, nasal discharge, lack of appetite and depression. Those symptoms persisted for 13 days following infection and were more severe in the exercising horses. Fever also developed in all horses and was persistent for 11 days following infection. Pneumonia eventually developed in all horses, with the viral infections being more dramatic in the exercised horses. While all horses experienced weight loss within four days of infection, exercised horses lost 40 more pounds than those having stall rest, and the exercised horses continued to have lower weights for a month. Exercised horses also appeared to have a delayed recovery from exercise.

Obviously, the exercised horses tended to exhibit more severe clinical signs of respiratory disease from the first day of infection until about the ninth day following infection. Clinical signs were resolved in both the exercised horses and those receiving stall rest by the fourteenth day following infection.

While horses infected with influenza were able to exercise without developing incapacitating disease, and while it appears that the exercise did not prolong the effects of the virus, it is important to note that the study did not mimic the adverse conditions that might be encountered in training environments. Horse owners should keep in mind that in keeping their top athletes fit, it is best not to exercise their sick horses. If exercise is necessary, use only mild to moderate exercise at the maximum, i.e., walking or trotting on a line. Clearly, the effects of the disease will not dissipate any sooner than it normally takes for the virus to run its course.

If your horse contracts influenza, you should be cautious about exercising your horse at all, and be aware of the signs of distress your horse might exhibit while exercising. Contact your veterinarian regarding methods you can use to prevent influenza in your traveling animal and what you can do to ease him through a couple of weeks of discomfort and misery.

About the Author

Diane Gross, DVM

Diane K. Gross, DVM, is currently a PhD candidate at The Ohio State University under the supervision of Paul Morley, DVM, and is presenting her findings of this study during the 1997 AAEP Convention in Phoenix, Arizona. Research will continue in this area.

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