by Marilyn Munzert
If you have horses, you have flies, which are carrying diseases that can be a real threat to your horses’ lives. There are several ways that flies spread disease. They cause irritation with their bites leading to skin or eye problems. Because they move from horse to horse, they can also be responsible for the mechanical spread of bacterial diseases such as strangles and pigeon fever. They can carry and transmit disease causing organisms directly into your horse’s bloodstream and can be responsible for the spread of frightening, life-threatening diseases such as equine infectious anemia.
The first category of fly diseases includes those caused by direct damage from bites, or allergic responses to the flies’ saliva. These diseases affect your horse’s skin and eyes. When the fly bites, it damages the horse’s skin, causing inflammation, which causes swelling, scabs, and hair loss. Sometimes, substances in the saliva can cause an allergic reaction, and signs will be much more severe. Allergic dermatitis most commonly affects the horse’s belly, causing bleeding sores and scabs. When the horse attempts to scratch the sores, he may do even more severe damage to his skin.
Your vet may prescribe ant-itch shampoos and sprays to help relieve symptoms. If signs are severe, corticosteroids may be recommended to help relive the itch and inflammation. Treatments only target symptoms, however, so this problem can only be controlled if you wage a major battle against the flies.
Flies like to congregate around your horse’s eyes to feed. If swelling, redness and a discharge that becomes thick and gooey appears by the eyes, your horse probably has conjunctivitis. In some cases, lids can swell to the point where your horse can barely open his eyes.
Flushing your horse’s eyes with saline may be enough to solve the problem. If the signs persist, you should schedule a visit from your vet, who’ll make sure there is nothing more serious going on before prescribing medication. If the flies deposit bacteria in the eyes causing infection, antibiotics will be necessary to solve the problem. Fly control is the most important strategy for treating and preventing conjunctivitis.
When flies walk through pus or discharge on a sick horse or in a contaminated area, and carry bacteria to infect your horse, they become the cause of life-threatening diseases. When a fly carries the strangles bacterium to your horse, it’ll take between three and 14 days before signs appear. First the horse will have a fever, followed by a nasal discharge. After several days, your horse may have swelling between his lower jaws. These abscesses can become quite large, and may eventually drain large quantities of pus.
Your vet can easily confirm a diagnosis of strangles with a bacterial culture of the draining pus. Take steps to control spread of the disease by isolating your sick horse, minimizing the contaminations of the stable and controlling flies.
Pigeon Fever is also caused by bacteria carried by the fly, placed on your horse when the fly feeds on the belly or chest. First there are small swellings that become large abscesses, often located on the chest area, giving the appearance of a “pigeon breast.”
Your vet may lance and flush these abscesses to allow them to drain. Your horse may have a low grade fever for a period of several days. Control spreading by minimizing contamination of the environment from draining pus. Confine the horse, and control those flies.
To control flies, the first step is to control the environment. If there is nothing to attract the flies, they won’t come. Keep stalls, paddocks and pastures clean. Flies like filth and manure. By keeping stable areas clean, they’re less likely to congregate.
Manage the manure by compost it, or have it hauled away. Avoid spreading fresh manure on pastures.
Eliminate standing water such as wet, mucky ponds. Provide adequate drainage to prevent water from accumulating in low-lying areas.
Provide adequate ventilation with fans in the barns. Flies prefer stagnant air, where they can lounge around without a worry.
Consider feed-through fly control for your horse. These products pass through your horse’s digestive system unabsorbed, and inhibit development of fly larvae in the manure.
Release predators on the manure pile. Small wasps consume fly larvae to help minimize numbers of flies that mature.
Place fly traps in strategic locations around your barn to trap and kill adult flies that manage to emerge in spite of your other efforts.
Apply fly spray regularly to make your horse less attractive.
Fly masks, fly sheets, neck covers and fly bandages are available to protect your hose’s body from fly attacks.