Rabies, an uncommon disease in Colorado, began a steep rise in the state starting in 2008. The first case in a horse was confirmed in Douglas county in 2009, and a sharp increase in the number of cases in skunks has been noted in 2010. Recently, rabies cases were reported in skunks in Adams, Arapahoe, Douglas, and Elbert counties. It is this sudden increase in the disease that is causing health officials and veterinarians to recommend vaccination of horses.

The distribution of skunk rabies, in the US seems to stop right at the eastern Colorado state border. That is not the case anymore. Positive skunk rabies cases have been documented in several eastern Colorado counties. The concern is that the virus is moving westward towards the Front Range of Colorado. Counties along the Front Range are more populous in people and horses, and so there is a potential risk to humans, dogs, cats, livestock, and horses.

• In 2005, there were 44 positive cases of rabies; all of these positives were bats.
• In 2006, there were 70 cases of rabies in Colorado–all bats, no skunk cases.
• From January 2007 through August 2008, there have been 18 positive cases of skunk rabies.

Skunks are the most common species involved in the transmission of rabies virus to horses.

So what’s the deal with rabies?

Is there a need for concern? Maybe not concern as much as proactive prevention. Consider the following:

1. The disease is fatal to mammals. In people, the disease is fatal unless treated.

2. If your horse gets rabies and has NOT been vaccinated, it is fatal.

3. You must be treated if your horse gets rabies.

4. If a horse gets the disease from a skunk or bat, the horse can contaminate you while the horse is acting normal, before showing signs of the disease.

5. The incidence of rabies has increased considerably in Colorado over the past two years.

6. Two cases were confirmed in horses in 2009, 2010; none for 30 years prior.

7. This disease is moving into the West.

8. Although previously it was the bat most likely positive for rabies, in 2009 and 2010, it is the skunk, meaning it is much more likely that a horse can get the disease.

Symptoms and Transmission

Animals that become infected with the virus may show no disease symptoms for several days. But during that time, they can transmit the disease through saliva to other mammals. Although rare, a horse could be infected and yet be free of clinical signs, but still be able to transmit the virus through his saliva into a cut on your hand. If horses are vaccinated, the chance of them getting the disease is very rare.

A horse with rabies will die. The virus infects the central nervous system, causing brain disease and ultimately death. Clinical signs are extremely varied, from colic to difficulty swallowing, depression with loss of appetite, a low-grade fever, lameness and/or incoordination, other neurological symptoms including convulsions, increased sensitivity to being touched, abdominal pain (straining to urinate or defecate), odd behavioral changes, nervousness, irritability, muscle contractions, and finally death.

Prevention and Control of Possible Infected Animals

Controlling and preventing skunks from coming into contact with your horses is one of the best ways to avoid contamination. Beware of unusual behavior including wild mammals that show no fear of people and pets; nocturnal animals that are active in daylight; and bats found on the ground, in swimming pools, or that have been caught by a pet. Rabid carnivores, such as skunks, foxes, bobcats, coyotes, dogs, and cats, may become aggressive and may attempt to bite people, pets, and livestock.

If you observe a wild mammal acting strangely, especially a skunk, or if you find a dead skunk that isn’t on your property, stay away from it. Strange behavior for a skunk would include being out and about during daytime hours and possibly looking unkempt and uncoordinated. If you must remove a dead skunk on your property, wear rubber gloves or lift the carcass with a shovel or other tool. Double-bag it for the trash.

Don’t feed wild animals or allow your pets around them. Be sure to teach children to stay away from wild mammals. Contact your veterinarian if your dog or cat is bitten or scratched by a wild animal, such as a skunk, bat, fox, or raccoon. If you suspect you’ve been exposed to rabies, contact your physician without delay.

One of a veterinarian’s primary responsibilities is the protection of human health in relation to animals. Discuss rabies vaccination of your livestock with your veterinarian. Vaccination should be considered for horses and other equines, breeding livestock, dairy cattle, or other high-value livestock, especially in areas of the state where skunks have been diagnosed with rabies.

Diagnosis and Vaccination

Diagnosis is difficult in the course of rabies infection because the symptoms can mimic many other diseases. Even if you suspect a skunk bite, examining your horse can be very difficult. The bite is extremely small and easily hidden by hair. Rabies in horses is fairly rare, but it would seem after considering the recommendations of veterinarians, the incidence of wildlife rabies, and the course of the disease, the benefits of vaccinating horses for rabies may outweigh other potential reasons for not vaccinating horses in Colorado.

So should you vaccinate? YES, because the disease is fatal, because you can get the disease from a horse that appears completely normal, and because rabies is preventable. The vaccination is an intramuscular injection, and no stall rest or special care is required after receiving it. The vaccination for a horse is a one-dose shot, once a year.

Dr. Barbara Page is the lead veterinarian and owner of Colorado Equine Clinic in Littleton, Colo. In addition to 24-hour full service general equine care, CEC’s nationally recognized Lameness Center has more than 32 years of experience in the successful diagnostics and treatments of lamenesses in all types of athletic and companion horses. For further information, visit www.coequine.com or call 303/791-4747.

Related articles:

• Horse Dies of Rabies in Colorado
• WEBINAR | Understanding Equine Rabies