Horse Fly Diseases

Horse flies are more than just a noisy summer nuisance. They can spread parasites and diseases from sick horses to healthy ones, including diseases that are contagious to humans. This is why it is so crucial for all barns and stables to have a regular program of fly management. Such a remediation program should include manure removal, spreading the manure in the sun to kill fly eggs and using fly repellent on all horses.

This is an annoying skin condition similar to human eczema, wherein the horse loses hair in patches due to itchy skin. The affected skin often develops a thick crust, which drips a transparent oily liquid when scratched. Horse flies spread this condition by biting a sick horse and then biting a healthy horse.

Anthrax is caused by a microscopic fungus. A horse fly can transmit it from a sick animal into a cut or open sore on the body of a healthy animal. Symptoms of anthrax in horses include colic, loss of appetite, lack of energy, tremors and diarrhea with blood. People working with horses are also at risk of getting anthrax, as are other mammals living near horses.

Also known as swamp fever or slow fever, this is a potentially lethal contagious disease in horses. This disease is caused by a virus. The symptoms worsen very quickly, so a vet must be called immediately if there is any chance at saving the horse. Symptoms include loss of appetite, high fever, problems with coordination and fatigue.

First isolated on the American East Coast, this condition has spread around the world via horse flies and ticks as vectors. Symptoms include fever, colitis, lameness and diarrhea. Pregnant mares that are infected with Potomac Horse Fever will often loose their foals. According to The Complete Equine Veterinary Manual, there has been some success with antibiotic treatments.

As its nickname suggests, this disease originates with dead rabbits (or rodents). Flies bite the corpse and then move on to bite other mammals, including horses and humans. Ticks can also spread this disease. Although not usually fatal to horses or humans, it can be deadly to pet rodents and rabbits. Symptoms include fever, nasal dripping and cough.