Horse health Q & A: Horses and rabies

Farm Forum

Q What is rabies?

A Rabies is a virus that can infect animals and people alike. The virus is fatal, yet preventable by vaccination.

Q How can my horse contract rabies?

A Horses become infected with rabies when an infected animal bites or scratches them. In South Dakota, skunks are the most common carrier of rabies and the most likely animal to infect a horse with the rabies virus. Rabies can also be transmitted when an abrasion is in contact with saliva or mucous membranes from an infected animal.

Q Is my horse at risk?

A Horses, donkeys, and mules are not among the most common animal affected by rabies, representing less than 1% of the total number of U.S. rabies cases annually. However, 23 horses were diagnosed with rabies in South Dakota during the years 2003-2012. In most years, at least one South Dakota horse is diagnosed with rabies. While this number is small, the consequences are high as the disease is fatal and may also present a threat to humans that are in contact with infected horses.

Q How does rabies affect my horse, and what are the clinical signs?

A The virus, which is transmitted in the saliva of an infected animal, is deposited in local muscle tissue in a bite wound. The virus can reproduce and survive in the muscle for varying durations before it enters the nervous system of the horse. Because rabies affects nervous tissues, including the spinal cord and brain, neurological signs are commonly associated with infection. Behaviorally, horses may present as either depressed, or manic. There are a multitude of clinical signs that horses display including fever, poor appetite, progressing to blindness, trouble swallowing and excessive salivation, muscle spasms, lameness, incoordination, incontinence, and paralysis. Sudden death is also included as a clinical sign of rabies. The interval between onset of symptoms and death of a horse is very short, often only five to seven days. A veterinarian should see any horse that is salivating excessively or showing neurological signs.

Q What should I do if I suspect my horse has signs of rabies?

A Limit exposure of people and all animals from the horse. Contact your veterinarian immediately. Unfortunately, an accurate test for live animals is not available. Your veterinarian will make an assessment of the situation. If rabies is strongly suspected, euthanasia may be the only wise option. Laboratory testing of brain tissue is currently the only way to confirm or rule out a diagnosis of rabies.

Q What should I do if I suspect my horse has been exposed to rabies?

A Again, limit exposure of people and all animals from the horse and contact your veterinarian immediately. They will want to know about all animals and people who have been in contact with the horse beginning 48 hours prior to the onset of clinical signs. If a suspect rabid animal, for example a skunk, is known to have bitten or otherwise exposed the horse, the outcome will depend on whether that suspect animal is positive for rabies. If available, rabies testing should be performed on the suspect animal. If the suspect animal is negative for rabies, then no further actions are necessary for the exposed horse.

If the rabies-suspect animal is positive or cannot be tested, the outcome then depends on the vaccination status of the horse. If the horse is currently vaccinated for rabies, a booster dose of rabies vaccine is administered and the horse should be observed closely for the next 45 days. If the horse has not been vaccinated, the only wise choice may be to euthanize the horse, especially in cases of a known exposure to rabies. Alternatively, the horse may be kept in strict isolation and monitored closely for a six-month period, after which rabies vaccine may be administered.

When it comes to rabies exposures-or potential exposures–many situations arise in which there is no clear direction in which to proceed. Decisions should be made by state public and animal health authorities in the context of the safety of the people involved

Q How can I protect my horse?

A Horses that reside in areas where rabies is endemic, such as South Dakota, especially those with potential exposure to wildlife and other animals on pasture, should be vaccinated against rabies. A rabies vaccination program consists of an initial vaccination, followed by another dose one year later. After this, your horse will need a booster vaccination annually or every three years, depending on the product. It is critical to have veterinary involvement regarding rabies vaccination programs.

In addition to vaccinating your horses, risks due to rabies can be minimized by vaccinating all cats and dogs that live on your property, even those that reside predominantly indoors. Limiting your horse’s contact with wildlife will also decrease the risk of rabies.

Q What is my risk?

A Rabies is a zoonotic disease, meaning it can be transmitted between animals and from animals to people. Vaccinating animals that you work with, especially pets and horses, is the most important step you can take to minimize your risk of exposure. Do not feed or attempt to pet wildlife. If you are bitten or scratched by a suspect animal wash the wound with soap and water and contact your physician. Depending on the circumstances, post-exposure rabies prophylaxis may be warranted. Know your animals. If your horse is exhibiting unusual behaviors including any unusual clinical or behavioral signs of rabies, approach the animal with care and contact your veterinarian immediately.