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Rabies in livestock often forgotten

Six tips to avoid rabies exposure

Rabies is a disease based in antiquity. It has been described through pictures and text since ancient times. The end result hasn’t changed: living creatures get rabies; they die. Globally, rabies claims over 55,000 human lives every year from every continent in the world except Antarctica. Fortunately, rabies is a relatively rare disease in humans but remains a disease of public health significance. Recognizing clinical signs of rabies in animals, protection through vaccination and initiating post-exposure treatment early remain very effective deterrents.

Laboratory-confirmed cases of rabies in animals (Canada) average between 150 and 200 positives every year from around 3,000 submitted samples. In Canada, the animals that most often transmit rabies are bats, skunks and foxes.

During my years in veterinary practice through the 1970s, I saw three cases of rabies in cattle. One case occurred in a Charolais-Shorthorn cross 4-H steer named Henry, housed in a barn and attended to every day by a 14-year-old boy, Jason.

After doing chores one morning, Jason mentioned during breakfast that Henry seemed anxious. He appeared nervous and tried to kick Jason when he walked up beside the steer to groom him. Henry tried to eat, but could not swallow the mouthful of supplement he hesitantly grabbed out of the tub Jason placed on the floor in front of him.

The father and Jason returned to the barn right after breakfast and found Henry lying down and barely able to stand. They called me.

It did not take long to determine that the 4-H steer’s temperament had changed from being very docile to aggressive. Combined with what appeared to be progressive paralysis, I immediately thought of rabies and questioned Jason and his dad about whether they were aware of skunks or bats in the area. Jason recounted that a week ago there had been a skunk in the barn eating out of the cat dish, from which they fed two barn cats kitchen scraps. The skunk wandered off and nothing more became of the incident. Everything remained normal until that morning.

I explained that I considered rabies a possible diagnosis and that I would have to inform the Canadian Food Inspection Agency (CFIA) of my suspicion. I then asked if Jason or his dad had been in contact with saliva from the steer. Both had reached into the steer’s mouth, thinking the animal had a foreign body wedged between its tongue and cheek — something many people do with rabid cattle. I went on to explain that if the steer, in fact, had rabies it would probably die in the next 24 hours and that the CFIA would harvest the brain for diagnostic work at a federal laboratory.

Jason and his dad were very upset and worried, not only about Henry’s fate, but also about the risk they both faced. I assured them that their doctor would initiate appropriate rabies prophylaxis with public health authorities. There would be no saving Henry.

Both Jason’s dad and Jason would probably receive human rabies immune globulin and at least two doses of a human rabies vaccine three days apart if the steer turned out to be rabies positive. I reassured them that treatment success had proven excellent. Rabies biologicals are readily available for exposed individuals, and are close to 100 per cent effective if administered promptly and properly. The family should ensure the up-to-date status of their farm dog’s rabies vaccination program and ensure all cats were vaccinated for rabies. Cattle and horses can be vaccinated, something we could consider. Cost and relative risk would come into play.

What you need to know about rabies

There are a few things 4-H clubs and other industry groups need to keep in mind. For one, rabies is not as rare as many think.

Some animals are more likely to transmit rabies than others: bats, skunks and wild carnivores represent the highest risk. Raccoons in some areas are major reservoirs.

Animals may not “act” rabid. The most typical signs of rabies are unexplained paralysis and a change in behaviour. Both “dumb” and “furious” syndromes exist.

Post-exposure prophylaxis (PEP) isn’t nearly as bad as it used to be. Routine vaccinations are available for high-risk groups (veterinarians, laboratory staff, animal control officers, veterinary students, veterinary technicians, wildlife workers, shelter employees, spelunkers/cavers).

If a bite does occur, wash the bite wound immediately with soap and water. Promptly seek medical attention and guidance from a physician. Take rabies PEP if prescribed by a physician. The physician may also prescribe antibiotics and a tetanus vaccination depending on the nature of the bite and the circumstances of the bitten person. Note that the PEP regime no longer features the much-feared extensive treatment of vaccinations across the abdominal wall. Today, treatment consists of a dose of human rabies immune globulin (based on weight) and a series of two to four vaccinations (five vaccinations for immunocompromised individuals) over a month period. If you are travelling to a foreign area with enzootic rabies, you should consult with a physician about getting pre-exposure vaccinations as well.

You are more likely to be exposed to rabies by a pet than by wildlife. One of the best ways to protect not only your pet but also yourself is to vaccinate your pet against rabies. Remember: Although wildlife in the U.S. typically accounts for the 90-plus percentile of yearly rabies cases, your pet can be exposed via the rabid wildlife and bring the disease into your home.

Rabies incubation periods vary. Although they can range from days to years, the average is three to eight weeks. This range is why it is important to promptly receive PEP.


Six tips to avoid rabies exposure

  1. Avoid approaching strange animals.
  2. Do not handle downed bats.
  3. Report bites to the proper officials – for example, the local rabies control authority, animal control officer, game warden or local health department employee. For children, a teacher or parent is a good reporting resource.
  4. Do not feed wildlife.
  5. Do not handle sick, injured or dead animals.
  6. Teach children how to correctly behave around an animal to avoid being bitten.

About the author

Columnist

Dr. Ron Clarke

Dr. Ron Clarke prepares this column on behalf of the Western Canadian Association of Bovine Practitioners. Suggestions for future articles can be sent to Canadian Cattlemen ([email protected]) or WCABP ([email protected]).

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