Vaccinations & Horse Diseases

Quite a bit of confusion surrounds Dryland Distemper, (aka pigeon fever) which is endemic to the southwestern United States. The fact that this disease is always present in Southern California virtually assures that it will show up somewhere in our practice area of Orange County each year.

Much of the concern on the part of horsemen is caused by the name being confused with “canine distemper” in dogs. Distemper in dogs is caused by a virus, so it is not treatable with antibiotics. It is easily and commonly prevented through vaccination because the disease is frequently fatal to dogs that contract it.

Dryland Distemper, which generally causes abscesses on the chest, belly, and inguinal region, is caused by a bacterium (Cornye bacterium), so it can be treated with antibiotics. Dryland Distemper does not usually transmit from horse to horse by direct contact. The vector for spreading the disease from horse to horse is actually a flying insect with a range of about a quarter of a mile. As a result, quarantine is a very inefficient way of trying to limit the spread of this disease.

There is also a disease in horses which horsemen refer to as “Distemper,” but it is most commonly referred to as “Strangles.” The common name Strangles is used because the disease causes swelling of the lymph nodes in the throat region, can cause difficulty breathing and a fever, and is highly contagious. Strangles can be transmitted from horse to horse by indirect contact. Therefore, strict isolation and quarantine are indicated. Strangles is also caused by a bacterium, so it is susceptible to treatment with antibiotics. It has an effective preventive vaccination. It is usually not fatal.

There is no vaccination available to prevent Dryland Distemper (Pigeon Fever). As a result, horses are either susceptible to the disease, or they have immunity as a result of natural exposure earlier in life. Simply put, either your horse has had Dryland Distemper, or it is going to get it eventually.

Fortunately, horses seldom run a fever or become sick when they have Dryland Distemper. Treatment is usually limited to lancing and draining any abscesses which might develop and, on occasion, putting the horse on antibiotics to speed recovery.

Unfortunately, the immunity which a horse develops from contracting Dryland Distemper does not last a lifetime. Horses will sometimes develop the disease more than once in their lives.

Prevention is limited to avoiding the bites of the insects which transmit the bacteria that cause the disease. The insects bite on the underside of the horse’s belly, so it is often suggested to apply a two to three inch wide ribbon of “swat,” or other fly ointment, on the belly from the cinch area to the sheath or udder.

Contact us for more information

For a variety of reasons, including the fact that Dyland Distemper makes horses very sick, it is unlikely that a vaccination for this disease will ever be commercially available. To learn more about Dryland Distemper aka Pigeon Fever in Orange County, fill out our online contact form or call us at 714-777-3942.