By Heather Smith Thomas
Rabies may be the last thing you suspect when a horse or cow gets sick, yet it’s important to keep rabies in the back of your mind because this is the most serious disease that humans can get from animals. Rabies can affect all warm-blooded animals and is caused by a virus that affects the nervous system. It is transmitted by saliva of an infected animal, via a bite or saliva coming in contact with mucous membranes, such eyes or mouth, or any opening in the skin.
Dr. Ann Dwyer, DVM, Genesee Valley Equine Clinic, Scottsville, New York, said skunks, foxes, bats, and raccoons are the main animals that transmit this disease. Rabies in horses or cattle occurs infrequently but they are still at risk. Dr. Dwyer was involved in diagnosing three cases in horses and they were very different in symptoms, illustrating the fact that rabies can look like just about anything.
One mare was acting strangely and bellowing, aggressively lunging at anyone who came near her stall. The second case was a horse that was simply dull, not eating, with a fever.
“I thought the horse had influenza, so I did a physical exam with my hands in its mouth, and didn’t wear gloves,” she said. “That horse showed no neurologic signs. It just wasn’t doing well. By the next day it lost the ability to swallow. I sent the horse to Cornell University, still not suspecting rabies. The veterinarians at Cornell didn’t suspect rabies either because they ended up with several people having to get the post-exposure treatment. I also had to receive the treatment.”
The third case she diagnosed was a horse that came from Montana. The new owners in New York had been told that the gelding had all his shots.
“But later, we found he had not been vaccinated for rabies,” Dwyer said.
This horse seemed lame, then it acted colicky, but not lame.
“The more we watched, the more puzzling it was. The horse was rapidly getting worse. Children had been handling the horse, so we explained to the family about the possibility of rabies, and they were okay with euthanizing the horse, to send the brain for checking,” she said.
“When you get the head off there is cerebral-spinal fluid to deal with so we use garbage bags, rubber dishwashing gloves (two pairs doubled), protective suits and booties, a cap and mask. We double bag all the samples and put them in Tupperware containers, one inside another to send to the lab,” she explained.
The best prevention for rabies is annual vaccination. In 2008, the American Association of Equine Practitioners added rabies to the list of core vaccines that should be given to every horse. Even if horses are in stalls, rabid wildlife may come into a barn. A barn cat may be bitten by a rabid animal and pose a risk to horses or humans in the barn.
Horses are curious; they’ll walk up to an animal that’s acting strangely and get bitten. Last fall, one of Dwyer’s clients, Mary Delton, observed her gelding being bitten by a skunk that was acting strangely. Delton happened to be out in the barn where she could see her horses in their paddocks. She saw a skunk dragging part of a dead animal into the garage and decided to keep an eye on the skunk.
“I never expected it to come to the barn where I was doing chores, but when I went to dump the wheelbarrow, I saw the skunk in the paddock with my mares. I yelled at him and ran out there and he ran under the fence and into the geldings’ paddock. I grabbed my iPhone and started taking photos. The horse kicked the skunk and then the skunk ran back and bit the horse on the fetlock,” Delton said.
“After he bit the horse and I continued to yell at him, the skunk started running towards me so I ran to the barn, closed the doors and called 911. I captured the skunk by putting a muck bucket over it. The sheriff came and shot the skunk.”
The skunk’s brain was tested, and was positive for rabies. Because the bitten horse had been vaccinated, the only action needed was a booster immunization. If this had been an unvaccinated horse, the authorities would have insisted on euthanasia, or expensive quarantine for that horse.
“My vet (Ann Dwyer) and the county health department said that if the annual vaccination was within six months of when the horse was bitten, he should be fine. But for this horse it was seven months, so he got a booster the next day,” Delton said. “It’s possible that some of the other horses could have been bitten but I didn’t see it happen. Fortunately, they were okay because they were vaccinated more recently.”BACK