Once Bitten...
Re-transmitted/published with permission of Covey Rise magazine. Copyright 2008. This article appeared in Covey Rise Magazine in summer of 2007.
By now, most bird dogs owners have heard about the rattlesnake vaccine for canines that has been on the market since November 2004 (July 2003 in California). Red Rock Biologics is the company that manufactures and markets the vaccine, Crotalus Atrox Toxoid. The product has been widely utilized now these last few years by many owners of hunting and working canine breeds. The vaccine is designed to protect dogs against the venom of the Western Diamondback Rattlesnake. There has been a great deal of discussion about this product, it’s use among dog owners, the availability and efficacy of the vaccine, and the potential risks of administering the vaccine to one’s valued canine companions.
After doing a fair amount of research on this vaccine and speaking to many other dog owners, I decided to have my dogs vaccinated prior to the ’06-‘07 season. I was traveling to an area known for not only holding an abundance of wild quail, but rattlesnakes as well. There are many creatures that share the same rural habitats where quail thrive, including more humans than ever. I decided to seek an interview with Red Rock Biologics knowing that other hunter/dog owners would want to know how more about the use of their product. So I spoke to several veterinarians around Texas and points west where I knew they would treat more Western Diamondback bites than most of their colleagues. After almost three years on the market I was unable to find many vets that have treated a known rattlesnake bite on a dog that was vaccinated with the product prior to being bitten, so data is coming in to help clarify research, but it is arriving rather slowly. One thing that I noticed very early on in my interviews is that the urban sprawl in America means more humans are relocating to rural areas and that clearly means more encounters with venomous snakes by both them and their pets. This was brought to my attention by more than one veterinarian as a consequence of rapid growth in their areas. It also means more household pets are being threatened by snakes and therefore are potential candidates for the vaccine. It appears that a far greater market exists for cats and pets as vaccinates than I first considered.
Last fall I was able to interview Dr. Dale Wallis from Red Rock Biologics and ask her questions about the vaccine that would be of particular interest to the bird dog owner. I found the pod cast interview with her that Bird Dogs Forever had published about a year earlier, and that was quite informative, but I had more questions still. The interview is presented here in its entirety, edited only for grammar and punctuation, and will hopefully answer some of your questions and will certainly raise some more. At the end I will share a few insights pertaining to the research data on the efficacy of the vaccine that were raised by the veterinarians I consulted both before and after the actual interview took place. Although I am not a scientist or a doctor, as an avid hunter I simply wanted to know more about this product and how it affects my choices to protect my dogs from rattlesnakes.
Dr. Dale Wallis / Red Rock Biologics
Rattlesnake Vaccine Interview - September 2006
1-Work on the vaccine began with the bites of two cats, can you tell me about that please, Dr. Wallis?
The rattlesnake vaccine concept was developed over a period of years. Our firm, Hygienic Biological Laboratories, has been researching, developing, manufacturing and selling vaccines since mid to late 1991. Begun by Jim Wallis in 1991, I became an owner of Hygieia in 1997 as part of Jim's and my divorce settlement. We remain partners and co-owners of the corporation. One of Hygieia's initial developments was a vaccine to protect against botulism toxin produced by Clostridium botulinum. We have also made vaccines against other Clostridial toxins such as perfringens, and tetanus. Jim Wallis recalls thinking about a vaccine against rattlesnake toxin based upon warning comments from his roommates regarding the dangers of rattlesnakes; this may have been in about 2000. The impetus to actually begin researching and developing the rattlesnake vaccine occurred in July 2002, when my husband killed a four foot rattlesnake under our front porch. We were alerted to its presence about ten p.m. from the "buzzing" sound under the porch. What we didn't know at the time was the snake was angry and buzzing because our little cat had challenged it and gotten bitten. "Punkin" took a bite to the front leg and hid for two days before returning home, nearly dead. We nursed her for two more days before we began to believe that she might survive. She never fully recovered; the effects of the venom resulted in permanent injury. As a result of this encounter, Jim and I began work in earnest to develop our ideas into a commercially marketable vaccine to prevent such injuries to other animals. We chose to focus our initial work on the Western Diamondback venom because this is arguably the most dangerous snake in the United States based upon the virulence of it's venom, the aggressive nature of the snake, the large size of the snake, the quantity of venom and the efficiency of the venom delivery system, and the large range in which the snake lives. We focused on application to working dogs (herding, search & rescue, hunting) because we believed they were at
the greatest risk. Our first dog trials began in November 2002.
2- How long has the vaccine been on the market?
Approved by the USDA since July 2003 in California, November 2004 for rest of the United States. The rattlesnake vaccine data was strong enough by July 2003 for the California Department of Food and Agriculture to issue Hygieia a product license. Jim chose to market the vaccine through Red Rock Biologics, a start-up corporation created for that purpose. California is unique in that we have our own biologics program and regulatory authority. California utilizes the same biologics regulations (Title 9, Code of Federal Regulations) as the U.S. Department of Agriculture, plus some tailored to California's unique agricultural requirements to oversee biologics product development and production. The smaller bureaucracy in California is more nimble and responsive, able to process applications and review data more quickly than the federal government. This California license enabled sales of the rattlesnake vaccine in California long before the U.S.D.A. (not the F.D.A. as some have thought mistakenly) granted their license, based on the same data, in November 2004.
3- How is the vaccine injection given?
The vaccine is given subcutaneously. We have found that it is a bit
sensitive to placement, in that the fewest injection site reactions are seen
if the vaccine is deposited fully under the subcutaneous fat, rather than in
it. Aside from the fact that these site reactions usually do not bother
the dog, and generally resolve on their own, the "silver lining" to site
reactions is that dogs which develop them are actually responding more
strongly to the vaccine, and develop higher antibody titers. Two doses are
recommended in the initial series for most dogs; they should be given thirty
days apart. Peak titer response is seen 30-45 days after the most recent
dose, so the series should be started about sixty days before anticipated
exposure to rattlesnakes. The antibodies formed following vaccination
persist for six to nine months in about half of the vaccinated dogs; in some
dogs, antibodies may persist for over a year. Single dose boosters are
given at six to twelve month intervals following the initial series,
depending upon the length of time the dog may be exposed to rattlesnakes.
In practical terms, if the "snake season" lasts six months or less, a single
booster given thirty days before the start of the "season" will suffice; if
the snake season is longer than six months, one booster should be given
thirty days before the start of the season, and another about half-way
through the season.
4- Discuss the best timing for giving injections to working/hunting dogs?
The highest antibody titers are seen around 30-45 days after the most recent vaccine booster; the optimum strategy is to time the vaccination so that peak antibody coincides with peak risk of rattlesnake bite. This means vaccinating thirty days before the activity occurs that will expose the dog to the risk of being bitten, whether it is hunting season, summer vacation, camping or hiking, or the end of snake hibernation in the springtime.
5-The vaccine is only for protection against the Western Diamondback at this time (which works well against copperhead bites too)?
The rattlesnake vaccine (Crotalus Atrox Toxoid) was created to generate
antibodies against the venom of the Western Diamondback (Crotalus Atrox) rattlesnake. The most data on the vaccine's performance has been generated in tests against this venom, and it is only labeled for use against this venom. Venoms are complex mixtures of many toxins; many contain fifteen to twenty or more proteins, peptides, enzymes, etc., designed to slow or stop a prey animal, and begin the process of pre-digestion. Many rattlesnake venoms contain components which are very similar to components found in other rattlesnake venoms. Because of these similarities, antibodies raised against the venom components of the Western Diamondback rattlesnake will also bind to components in the venoms from other species of rattlesnake. In > many cases, this antibody binding can also be shown to neutralize the components from other snake venoms, leading to a phenomenon known as "cross-protection", in which antibodies generated by the Crotalus Atrox Toxoid will also neutralize some of the components found in the venoms of the Western (Crotalus viridis), Timber (Crotalus horridus), Massasauga (Sistrurus catenatus), Copperhead (Agkistrodon contortrix), Sidewinder
(Crotalus cerastes), Red Diamond (Crotalus ruber) and Pigmy (Sistrurus miliarius) rattlesnakes. Antibodies generated by the Crotalus Atrox Toxoid have not been shown to have any neutralizing effects against the venoms of the cottonmouth (Agkistrodon piscivoris), the Mojave Green (Crotalus scutulatus), or the coral snakes. Part of the venom effects of the Eastern Diamondback venom are neutralized by antibodies generated by this vaccine, however, it is very limited.
6- Is Red Rock Biologics developing vaccines against other venomous snakes like Eastern Diamondback?
Other vaccines are in development, including one against the Eastern Diamondback venom. No timeline is yet available for these. I can’t comment further on our product pipeline.
8- Is the vaccine being widely accepted by the veterinarian community in snake-rich areas of the country?
Crotalus Atrox Toxoid is very well accepted in areas where rattlesnakes are commonplace. Over three thousand veterinary clinics currently offer the vaccine to their clients whose dogs may be at risk for envenomation. Clinics which treat scores to hundreds of snake bites per year feel the vaccine is making a real difference for vaccinated dogs.
9- Any data yet regarding the responses of dogs bitten by Western Diamondbacks that were administered the vaccine prior to bite?
Data on bite reports is being compiled for future publication. I can't comment further on this at this time.
10- Would you discuss general treatment for bites to a canine until the dog can be taken to a veterinarian for emergency care?
Treatment of vaccinated dogs is fundamentally the same as the treatment for unvaccinated dogs; it is just that vaccinates are more likely to present with minimal symptoms whereas non-vaccinates are more likely to present with more severe or progressive symptoms. First and foremost, get the bitten animal to a veterinary facility without delay. No intervention in the field has been scientifically shown to be more beneficial than getting to the vet as soon as possible, and most attempted treatments in the
field simply delay transport to a veterinary facility. Delaying evaluation and treatment in a snakebite is the biggest reason animals die. Veterinarians generally treat bitten animals according to how severe an envenomation each case presents; animals with mild symptoms usually receive just intravenous fluids, pain medications, antibiotics, etc. Animals with severe symptoms, or symptoms which appear to be rapidly progressing towards severe, will receive more dramatic interventions, which may include antivenin,
oxygen, plasma, etc., in addition to the medications given to less severe cases. The main difference so far between vaccinated and unvaccinated animals is that vaccinates usually experience less swelling, less pain, less tissue destruction, and more rapid return to normalcy than non-vaccinates. Only a veterinarian is trained to be able to evaluate whether a given envenomation is getting better, worse, or staying stable, and then
administering the treatment necessary for the optimum outcome.
11- Are bird dog and hunting dog (retriever) owners your core consumer demographic for this vaccine product?
While we initially believed working dogs would have the greatest need for this vaccine and would constitute the largest market, such has not been the case. Our human population is constantly moving out of the cities and into the suburbs and countryside. As they do, they and their animals are invading snake habitats, and more frequently encountering these rodent-controlling reptiles. Pets actually constitute the larger fraction
of animals being vaccinated, as it is not uncommon for rattlesnakes to follow their prey (mice and rats) out of the open countryside to the woodpiles, compost heaps, vegetable gardens, and garbage cans found in people's yards and garages. It is an off-label application; however, even cats are being vaccinated with this vaccine in endemic areas.
12- I read that Arizona has more human snakebite victims than any other state in America? I would think in a place like Arizona the vaccine is given to many different breeds of dogs and cats due to the snake's highly prolific nature in that environment?
The southern United States enjoys a climate which permits year-round rattlesnake activity. Pets which share yards with rattlesnakes in these endemic areas should receive boosters every six months to maintain maximal antibody titers. In most cases, indoor pets do not require the vaccine.
13- What, if anything, has changed regarding the vaccine and its application since the pod cast interview took place?
The pod cast was last fall (2005); I don't recall the date. There have been no changes in the vaccine since then. Research is continuing to develop information on the range of venoms the vaccine-elicited antibody will neutralize. There is also research into applications of this, or similar formulations, for other species such as the horse, goat, llama, etc., which are potentially exposed to rattlesnakes.
I have interviewed some veterinarians that treated known (the identification of the snake was made during the time of bite) rattlesnake bites on dogs that were previously vaccinated with the Red Rock vaccine. Some reported that these animals seemed to do well and have fewer symptoms than they have seen in previous, unvaccinated dogs that were bitten. Not one veterinarian reported any injection reactions to me; however I did read some of these on Internet forums. Keep in mind that such forums are questionable in that anyone can easily and quickly post any opinion on any subject. When the nationwide pet food scare and recall occurred this spring (2007) I read all sorts of posts on such Internet forums that lacked credibility. Both instances produced inflammatory postings containing accusations of company’s products killing their beloved pets. We know some dogs and cats did indeed die from tainted pet foods, unfortunately, but I could not verify one instance of a pet of any kind killed or seriously harmed by this vaccine.
One of the primary challenges with researching this vaccine is that so many variables exist when a venomous snake bites a human or a dog. Consider all of the following:
1-Approximately 25% of all reported snake bites are dry bites, meaning that no envenomation at all occurs. There are wide ranges of how much venom a snake might inject with each bite depending on many variables present at time of bite. This makes it very difficult to discern how well the vaccine has worked on a bitten dog (that was previously and properly vaccinated) when you can’t be certain of how much venom the snake injected. It is difficult if not impossible to have a control subject(s) in a scientific experimentation with all of these different variables present between dog bitten and the condition of the snake doing the biting.
Venom production in rattlesnakes depends on many variables including when the snake last ingested a meal, season or temperature, and the snake’s general health. Pit vipers (rattlesnakes) produce venom to aid in killing prey to feed and they have been shown to try and conserve it for subduing prey for food. Most snakes when confronted will try to escape, or bite without injecting much venom. It can take a snake a few weeks to re-build their supply of venom if it all gets used up. They are less active and feed less in fall/winter so they produce less venom then too.
3- Size of snake. Contrary to the old myth, younger snakes do not produce concentrated venom, but can’t control how much venom they inject with each bite as they will learn how to do later as a mature snake. (Compare to the human bladder and how controlling it is a learned behavior.)
4- Body weight of the bite victim can have a great affect on the outcome.
5- Location of bite on the victim. With canines, bites the trunk of the body carry more risk, generally speaking than would a bite to the extremities (paw, leg). Most dogs get bitten around the head or neck which can cause choking once the swelling ensues. We have all seen pictures of bird dogs with heads swollen to the size of a volleyball.
Every veterinarian I consulted agrees that any snake bite to human or canine must be treated as an emergency and get medical for the victim as fast as possible. Many bites occur in rural areas far from medical help. It is a good idea to have an emergency plan when visiting an unfamiliar area to hunt or enjoy the outdoors. Know where you would proceed to and how in such an emergency before you go. Do not cut on bites like you saw John Wayne do in the old Westerns, it can be dangerous and could potentially cause infection. I met one professional snake handler who has been bitten three times and he swears by the little venom pumps you can buy at as common as Wal-Mart for about $10-12 bucks, but he is not a doctor either. Snake-proofing dogs with snake avoidance training are likely a dog’s best defense against snake bite. Some vets told me they are not convinced of the efficacy of the vaccine yet, it’s too early to tell for sure, but they offer it to their patients (for about $40 bucks a year for the two shots) and have not yet had problems with injection reactions. Consult with your own veterinarian about the concerns specific to you and your animals prior to making a decision about using this product.
I gave my dogs the vaccine about 45 days prior to the onset of quail season in Texas so that they would have maximum protection in the early part of the season when temperatures are still warm and snakes still can be readily observed. This is when the greatest threat from snake bite occurs to my dogs in my particular case. My experience with the Red Rock product was that the vaccine had no negative effects on my dogs, and if it might help save their lives in the event of a rattlesnake bite for $40 extra bucks a year per dog, I will continue to give it to them until something changes that viewpoint. I found many bird dog owners (some that are veterinarians) that feel exactly the same way and will continue to use the product for their second or third year in a row, but still anxiously await more clinical data on the vaccine’s efficacy.
Any additional input regarding experiences with this product is welcomed at "rockinghoutfitters@gmail.com"
D. Collin Hudson