Saturday, July 23, 2011

The Truth About Rabies

Rabies is likely the most well-known threat to animals.  It is an acute viral neurological disease causing behavioral changes, ascending paralysis, and eventually death.  There is no cure for rabies once clinical signs have appeared.  While most animals have their own strain of this virus, each strain can cross species lines to infect other mammals.  The true canine version of Rabies has been eradicated in the US thanks to our vaccination programs.  The biggest threat is to our dogs, cats, cows, horses, sheep, goats, and us. It comes from strains of rabies found most commonly in foxes, raccoons, bats, skunks and coyotes.  Contrary to common thought, animals like mice and squirrels are an extremely low rabies risk.  One theory suggests it may be due to the fact that a mouse or squirrel attacked by a rabid animal wouldn't survive long enough to pass the virus on.  "Primitive" mammals such as opossums and rabbits are very resistant and low risk.  Birds and reptiles are resistant.

 There is no "vector", or animal that passes rabies from host to host, such as a flea or tick. It can only be transmitted directly from rabid animal to the next mammal.  Rabies *cannot* be passed by blood!  The virus lives in saliva and neural tissues, ie: the brain.  Infected saliva enters through a bite wound, open cuts on skin, or into mucous membranes.  For instance, if an infected dog licked your face and got into your mouth a bit.  There have been theories that Rabies can be aerosolized;  for instance, if a hunter killed a coyote and then severed it's head or somehow cut into the skull, exposing infected brain tissues.

Dogs, cats, ferrets, and humans can all be vaccinated.  There is a vaccine for horses and cattle, but may only be done when there is interstate transportation.  A person exposed to rabies, even if they've been vaccinated, will still have to undergo rabies treatment.  Wild animals cannot be vaccinated, nor can 'hybrid' dogs.  There have been programs where they were dropping vaccines into the woods in the hope of vaccinating raccoons who ate the bait, but technically if you had a 'pet' raccoon, you cannot get him vaccinated.

Even if you think your dog is at low risk for Rabies, vaccinate him.  If he were to bite and have no vaccination history, law requires him to be put down or put in strict isolation for 6 months, where neither you or any humans can have contact with him.  Rabies cannot be tested for on live animals; only by evaluating brain tissue post-mortem.  If you suspect your vaccinated dog may have come in contact with a rabid animal, don't panic.  Bring him to the vet where he will be revaccinated again.  You then just need to observe him for 45 days in your home.

Don't believe everything you see in Kujo.  The most threatening stage of rabies in an infected animal is when they show no symptoms.  This is called the "prodromal" stage which lasts 2-3 days.  It's the threat because our dog is still behaving perfectly fine.. kissing our faces and transmitting the virus.  The Kujo phase is called "furious" stage, where we see biting, roaming, photo phobia, and hypersensitivity to external stimuli. Animals act opposite of how they should.  A fox will become friendly and out in the daytime, a mean dog may become sweet.  2-4 days after clinical signs appear, they enter the last phase, "paralytic" or "dumb" form.  Their hind limbs become paralyzed, and that paralysis slowly moves up their body.  Eventually their jaw will drop and we will hear a change in vocal sounds due to paralyzing of the throat as the virus ascends.  This is also why there is excessive drooling and choking; they can no longer swallow.  The animal dies 2-7 days after 1st clinical signs appear.  The scary thing, is not all animals show their first signs of infection right away.  This can take 1 week to 1 year, and they will start to pass the virus a few days before their signs being to appear. 

Rabies scares me more than pretty much anything.  It's a horrible virus that is painful and deadly.  While law requires rabies vaccinations on our animals, do it anyway.  You do your puppy series of shots and then a 1 year rabies vaccine.  Following that, you can begin to get them vaccinated every 3 years.  Rabies risk to humans is low, because we know to avoid the fox or coyote that seems overly friendly or in places it shouldn't be.  Our vaccine is just about a grand, so people only tend to get vaccinated if they are biologists or veterinarians.. someone with an increased threat of exposure.

There has been one case of a girl who survived rabies after her 1st clinical signs appeared.  She is a sort of miracle case and the subject of many studies since.  Her mistake, was she saw a bat and figured that because it looked lethargic and sickly, it wouldn't be infected.  They thought that rabid animals always seem aggressive, and they were wrong.  She handled the bat, and it didn't even bite her.  The bat must have had saliva make contact with an open spot on her hand, and that's all it takes!

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