Rabies Testing & Quarantine

Today, VBB Central was closed down so our doctors could have a CE day. Continuing education is a valuable part of veterinary practice - it's how we keep up with what's going on in our profession medically, administratively, and so on. I usually enjoy my CE days a lot, although of course some lectures (and lecturers) are better than others!

Today, one of the talks was on the subject of rabies testing and quarantine, and rules applicable in various states and counties. The speaker was a veterinarian from her state's Department of Agriculture, and she was very dynamic and knowledgeable. Obviously the material she was working with was what it was - the nuts and bolts of vaccine, quarantine, and testing requirements are not very sexy - but nonetheless, she kept me interested the entire time. She even managed to gracefully handle the incessant "point of order" type questioning from the one guy in the back, who always has to ask a stream of arcane academic questions that are irrelevant to anyone living in the real world.

Here's the thing - dedicated readers of this site know that one thing most veterinarians have in common is that "nothing surprises us anymore." Except, you know, when the most stupid or ridiculous thing imaginable suddenly happens and it shocks the hell out of you, and you think "man, I THOUGHT I had seen it all, but I guess I was wrong." Then you think there's nothing left to surprise you - until it happens again.

Well.

This veterinarian was talking about how to properly submit samples for testing at the state diagnostic testing laboratories. Proper refrigeration is key, in case you are wondering, and she also recommends making sure everything is sealed well to avoid leakage and that identifying paperwork is enclosed, properly filled out, and in its own separate waterproof bag. There are various approved couriers, and instructions on how to deliver the samples without using a courier were also provided. She was very thorough. Then she got to the part about properly preparing the samples.

Well, ok, easy enough, right? You're either submitting a brain that has been removed from a head, or a head that has been removed from a body, or in the case of a very small patient (under 3 lbs) an entire body. She did take care to remind us that they only want mammalian samples. OK, I can see how someone might think it necessary to submit say a bird or something, if perhaps a pet chicken went batshit crazy and started attacking inanimate objects or whatever. So it makes sense she would remind us not to do that. Then she reminded us that they want only non-living samples. I am pleased to report that she did not provide us with an example of a living sample they had received in error.

So far so good, you're probably thinking. Where's the surprise? Well - apparently last year, she was going through the reports sent to her office from the state diagnostic testing laboratory, and was disconcerted to see that a particular sample had been "unable to be tested." She read the complete report and it said that the reason the sample could not be tested was because despite the fact that it had been labelled as a "bat," it was in fact not a bat but rather a banana peel.

I'll let that sink in for a minute.

It was not a bat, but rather a banana peel.

I am not sure how one makes that mistake, let alone how someone who mistakes a banana peel for a bat is then competent to package the banana peel up with the appropriate paperwork and submit it through the proper channels for delivery to the state rabies diagnostic testing laboratory. It kinda makes my head spin.

I did take the time this afternoon, after getting home from the CE, to put together this teaching slide for my own talks:

Feel free to use that yourself if you find it helpful. This is apparently something people need help with out there.

Rabies on the Brain

I’ve got rabies on the brain. Well, not literally, because that would mean I’d probably be dying in intensive care.

 
Last week (September 28) was World Rabies Day. It is the anniversary of the death of Louis Pasteur (more on him later).
 
Rabies is virus which causes a virtually 100% fatal neurologic disease in all mammals, including humans. According to “Rabies surveillance in the United States during 2011,” last year rabies was diagnosed in animals in 49 states (not Hawaii). Besides the “usual suspects” of bats, skunks, raccoons, foxes, dogs and cats, it was also diagnosed in cattle, horses, sheep, groundhogs, deer, beavers, otters, javelinas (shaggy piggy creatures), bison and alpaca. Bambi and Thumper could be rabid!
 
Rabies is spread by the saliva of a rabid animal. When the rabid animal bites a victim, it inoculates the virus into the tissues. Unlike most viruses and bacteria, which spread through the bloodstream, the rabies virus spreads along nerve cells. Depending on how far the bite wound is from the brain, symptoms might not develop for weeks to months to years. A person in the US died last year of rabies that was acquired from a dog in Brazil eight years previous! For eight years, the virus had been lazily moseying along, inexorably crawling up to the brain.
 
Once the virus hits the brain, bad things happen. Even in the 21st century, over 50,000 people worldwide die of rabies every year. It is a horrible death of alternating periods of lucidity and psychosis, pain, fever, convulsions, hallucinations and hydrophobia (pathologic fear of water).
 
I recently read Rabid: A Cultural History of the World’s Most Diabolical Virus, by writer Bill Wasik and veterinarian Monica Murphy. It’s a fascinating book, although I guess I might not qualify as a totally objective reviewer since I tend to get a little bit obsessed about public health and infectious diseases.
 
Wasik and Murphy weave together a history of rabies and civilization. Although many of the scary epidemic infectious diseases of humans, including Ebola, West Nile, SARS, swine flu, and hanta, are zoonotic (transmitted from animals), only rabies was known to be zoonotic before humanity ever considered the existence of bacteria and viruses. Think of bubonic plague (“The Black Death”): people didn’t realize it was caused by a bacterium spread by the bite of a rat flea. But rabies: slobbering psychotic dog bites human, human turns into slobbering psychotic animal. It was obvious even four millennia ago that rabies was transmitted by animals, particularly canines.
 
The book looks at theories, preventatives and “cures” over the millennia (the most effective preventative prior to vaccination was cauterizing the fresh bite with a red hot poker); history (St. Hubert is the healer of rabies sufferers); mythology (the slaver of Cerberus spreads both rabies and aconite); connections of rabies to werewolf and vampire legends; the handful of documented survivals of rabid humans; weird ideas that people have had to prevent rabies in dogs (one theory suggested rabies spontaneously arose in dogs due to sexual frustration and suggested prevention by creating “doggy bordellos”); rabies in various species (l’enfant du diable = the devil’s child, a skunk); history of canine mass killings in an attempt to stop epidemics; and a recent rabies epidemic on the supposedly rabies-free island of Bali.
 
The most fascinating chapter explains how Louis Pasteur developed the first rabies vaccine in the late 1800’s. In fifteen years of veterinary practice, I have never seen a case of rabies and hope I never do. Pasteur (who is also the father of pasteurization and food safety) was neither a physician nor a veterinarian, but was a really smart dude who was passionate about human and animal health.
 
You can’t grow rabies virus in a Petri dish. The only way Pasteur and his colleagues could grow rabies virus was by maintaining rabid animals in the lab, putting themselves at continual risk of gruesome death. At first they allowed a rabid animal to bite another to perpetuate the virus; then they started collecting saliva from slobbering aggressive dogs to inject into other animals. Eventually they hit on dicing up the central nervous system of a rabid rabbit and depositing it directly onto the dura mater of the recipient’s brain. By repeatedly transferring rabies directly from one rabbit’s brain to another they developed a highly virulent strain. The next step was to inactivate the virulent virus to make the vaccine strain, which they did by leaving the rabbit’s spinal cord out to air-dry for a few days. This air-dried infectious bunny brain was then injected as a vaccine: either a pre-exposure vaccine to prevent infection or a post-exposure vaccine to prevent development of symptoms after a bite.
 
The first human to receive the vaccine was a boy who had been mauled by a rabid dog. Can you imagine the agonizing wait for Pasteur to see if the boy survived or died? (He survived both the bite and the cure.)
 
We all learned in vet school that rabies is absolutely, guaranteed fatal. But some new research is showing it might not be completely 100% fatal. There was a girl in Wisconsin who survived clinical rabies after a medically-induced coma and months of rehab. And a recent paper was published in The American Journal of Tropical Medicine and Hygiene that looked at humans living in remote areas of Peru where vampire bats are a common carrier of rabies. 11% of the people had rabies neutralizing antibodies; they had not been vaccinated so those antibodies developed after infection with the real, live virus. How come they didn’t die? Has evolution favored people with a more exuberant immune system that can fight off endemic rabies?
 
However, despite this research, the odds of dying are still very, very high. Make sure your dogs, cats and ferrets are current on their rabies immunizations, and never approach an ill or strangely-behaving bat, skunk, raccoon or fox.

Playing Doctor

It was a lovely sunny day at the VBB hospital. The trees were getting some new green as the spring rolled in and there was the slight scent of wet earth that remained from an early morning shower. My day was ticking by, surgery in the morning, followed by afternoon appointments, when suddenly a gaunt figure in a large flowered hat careened into the front lobby.

By large flowered hat, I mean it was a hat with HUGE fuzzy flowers on it, worn by the famous "hat lady" in our little town in recognition of the first official day of spring. This particular lady had hats for all sorts of occasions, all worn as a partial jest and partial personality tic of the wearer.

On this day, the normally sunny countenance of Hat Lady was marred by a look of horror. She was holding an equally flowered handkerchief wound around her wrist. As I walked into the reception area, I could hear her demanding to know the rabies vaccination status of one of our patients. I explained that we were not allowed to release that information to her since she was the owner. However, after looking at the record and seeing that the patient, Teeth, had his last rabies vaccination within the year, I felt pretty comfortable telling her that I didn't think she had anything to worry about with regards to rabies. I advised her to go to the doctor to have the wound looked at and maybe a tetanus shot.

It was at this point that the Hat Lady started yelling that I had to give her a rabies vaccination. I told her that A) I didn't have vaccines for humans and B) I was not licensed to give a vaccine to a human. She kept saying that a rabies vaccine is a rabies vaccine and that she "demanded" that I give her one. When I told her that she would need to talk with her doctor and animal control about that, she got super dooper mad. She threatened to call my boss...I offered to dial the number for her. She threatened to call the board...again, I offered to dial the number for her.

When the police showed up (she had called them about the dog bite), both the officer and I were finally able to get her to calm down. As the dog in question was current on vaccines, he was quarantined for 10 days in the home of his owner and the Hat Lady never required a rabies vaccine (at least not yet).

This brings up some important things: One, a vaccine approved for dogs, cats, goats, cows, horses, etc is not necessarily approved for humans. In fact, I am struggling to think of one off of the top of my head. Two, most vets would rather you call the vet board because they refused to work on you rather than to have a board report for working on you. Hell, the vet at my undergrad even refused to pull a splinter out of the hand of a fellow student because he didn't want to get in trouble for working on a human.

The last thing to let everyone know is that rabies vaccines are important. It is against the law to not have your dogs and cats vaccinated and it is a bad idea to not vaccinate other animals. In the US, there are not large numbers of animals identified as being rabid nor are there large amounts of people dying from rabies. However, in places like China and India, those numbers increase exponentially. We can thank our relatively low rabies incidence to the efforts of the public health departments and veterinarians. That does not mean that we can relax our attitudes towards rabies. We have global travel of animals, including the adoption and importation of animals from places in the middle east, where soldiers are falling for homeless animals and trying to help them. Some of these animals can come to the US with rabies. So, thinking that you can extend the time between rabies vaccines beyond the scope of the vaccine is both illegal and dangerous.

A family in Florida just found this out. Their dog came in contact with a raccoon. The dog had not been vaccinated for rabies within the allotted time. Most rabies vaccines are either considered to be effective for 1 year or for 3 years. This dog had been vaccinated 7 years prior to the incident. Because of the lack of protection from the rabies vaccination and the contact with a raccoon, this dog contracted rabies. Rabies is diagnosed post mortem (after death) via a certain test on the brain cells. Once this dog was diagnosed with rabies, the humans in the household had to be vaccinated and the other family dogs were euthanized. In reality, after the unvaccinated dog came into contact with a raccoon, an animal species known to harbor rabies, the dog should have been euthanized or at the very least quarantined for 6 months or so. Rabies viral particles have to travel up the nerves from the site of the bite/contact into the brain, which can take a long time. Thus an animal can be infected, but not start showing signs or being able to transmit rabies for weeks to months, depending on the site of the bite.

As for the 1 year versus 3 year protocol, I am split on this. For animals that are likely to come into contact with wild life regularly, I would stick with the yearly protocol. I have read a report of a dog that contracted rabies in spite of being within the 3 year interval per his rabies vaccine. For those patients that are less likely to see hot wild life action (like my indoor, couch potato old lady dog), I would go with an extended, 3 year protocol. And just because your cat does not go outside, do not assume it is safe. There are enough people that find random bats in the house...and a bat bite often goes unnoticed, even when they bite a human. So, obey the law....and use some common sense. Some of my colleagues might disagree and they are welcome to do that. However, a classmate of mine told me that they just had a dog diagnosed with rabies in Virginia and there was also a recent report of a horse that was diagnosed with rabies in Tennessee.