If you have a horse, pony, mule or donkey, you have to deal with horsefly control. This includes not only putting fly repellent on your animals but spreading the manure in the sun so eggs can't hatch. Not only will these biting pests transmit diseases to your horses but to you, other people and livestock as well.
The fly bites a sick horse and then the fly bites a person or a healthy horse, thus spreading the illness. This causes itchy, crusty skin that oozes a clear fluid when scratched.
Flies can transmit this to horses and other livestock through their bites. It's very rare for a person to get this kind of anthrax, but people working with animals can get it.
Diseases spread by fly bites from sick horses to healthy horses include equine infectious anemia and Potomac horse fever. Only horses can get these potentially fatal diseases
Also known as rabbit fever, this rarely affects horses but can get people or pet rodents very sick. A horsefly bites a dead rodent or rabbit and then bites a healthy human.
Although horseflies have been suspected in spreading Lyme disease (New England Journal of Medicine 322:1752, 1990), there hasn't been any hard proof of this.