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As summer heats up and we head outdoors for fun in the sun, we have to deal with one of the more negative aspects of quality time outside; pesky insects that bite and harass. Horses don't get a break, either. Not only are insects frustratingly annoying to our horses, they also can carry diseases that infect horses, some of which can be life-threatening.

Just as in people and other domestic animals, the most common insect carriers, or vectors, of disease in horses are ticks, biting flies and mosquitoes (these are called arthropod-borne diseases). Because horses spend a lot of time outside in the summer, horse owners need to be aware of the diseases these insects spread, and take measures to protect their horses. Lyme disease, West Nile virus infection, and Western and Eastern equine encephalitis are all arthropod-borne diseases.

The good news is that vaccines are available that can help prevent many tick- and mosquito-transmitted diseases. Check with your veterinarian about appropriate vaccination schedules. Proper timing of vaccine administration is critical for some diseases. But there is more owners can do to protect their horses from diseases with and without available vaccines.

If you travel with your horse, learn about diseases prevalent at your destination. Even if you aren’t traveling far from home, as more and more horses (and potential vectors) travel greater distances, horses can come in contact with infectious agents from other areas they may not otherwise encounter. Avoid sharing tack and grooming supplies, and avoid direct contact with other horses when possible, as some infections can spread from horse to horse without the aid of a vector.

Another way to protect your horse is to enforce proper tick and mosquito control. Not only is vector control important for keeping humans and small companion animals healthy, similar measures help protect our companion horses from disease, too.

Avoid letting your horses have access to swampy, marshy water, a breeding ground for mosquitos that transmit diseases such as Eastern equine encephalitis. Shallow water sources, including water buckets, bird baths and watering tubs, are breeding areas for mosquitoes that transmit other diseases, such as West Nile virus, and should be drained and cleaned frequently.

Daily grooming can help owners find and remove ticks from horses. In temperate areas, ticks can live indoors and be a problem in stables. Keeping pastures mowed, and trimming brushy areas, are other good tick control measures. Insect repellants are available for horses, but make sure you check with your veterinarian before applying any products.

Morris Animal Foundation funded its first equine study in 1960. Since then, the foundation has funded almost 500 studies focused on equine health, including vector-borne diseases, as well as orthopedic problems, pain management, and a host of other diseases affecting companion horses.