The problem of venomous snake bites is significant. Though most dogs are never exposed to rattlesnakes, those that are exposed face a very serious risk. Because dogs and cats don’t know to stay away from venomous snakes, those that are exposed to snakes are about 20 times as likely as humans to be bitten. These pets are also about 25 times more likely than humans to die from a rattlesnake bite when bitten. It is estimated that about 150,000 dogs and cats are bitten annually in the United States by venomous snakes. Dogs and cats are over 300 times more likely to be bitten by a venomous snake than to get rabies. Snake bites can kill or injure dogs, destroy skin and muscle, and can cause permanent liver, kidney, heart, neurological, and joint damage. A snake bite in an unvaccinated dog can be severely painful and can cost the owner thousands of dollars in veterinary care. Veterinarians can not always treat snake bites because dogs are sometimes bitten too far from veterinary treatment, dog owners are sometimes unaware that dogs have been bitten, and dog owners can not always afford veterinary treatment for snake bite.
Keep the vaccine refrigerated at 35-45F. Never freeze the vaccine. Shake well before using. Each dose is 1cc, to be given subcutaneously just above the muscle and in the dead space under the subcutaneous fat and away from the mid line. This product is intended for use in healthy dogs, who are at least four months old, as an aid in the reduction of morbidity and mortality due to intoxication with Crotalus Atrox (western diamondback rattlesnake) venom. Administration should be by or under the supervision of a licensed veterinarian only. The product expiration date is two years from date of manufacture.
For the initial vaccination, two doses are recommended spaced 30 days apart. Typically, protection from boosters peaks about 30 days after boosters and lasts about six months. A dog should get at least one booster per year approximately one month before the beginning of his “rattlesnake exposure season”. Dogs exposed to rattlesnakes longer than about six months per year, or dogs at higher risk, may benefit from a booster every six months.
There may be a modified initial protocol for dogs over 100 Lbs or under 25 Lbs because very large and very small dogs don’t always produce enough protective antibodies from only two injections in the initial sequence. They may benefit from one additional booster shot 30 days after the first booster shot in the initial vaccination sequence (three doses total). For large or small dogs that did not receive this three-injection initial protocol, their regular subsequent boosters typically bring a dog’s antibody protection up to adequate levels.
Rattlesnake vaccine is designed to reduce the likelihood of death, permanent injury, and severe pain caused by rattlesnake bites. The vaccine stimulates the dog’s immune system to produce antibodies against rattlesnake venom. These antibodies typically last for several months depending on the individual dog’s response to the vaccine. These antibodies can neutralize rattlesnake venom in a way very similar to antivenin. The vaccine contains no sheep or horse proteins that can cause severe allergic reactions. Use of the vaccine does not contraindicate the use of antivenin as a treatment for rattlesnake bite.
The vaccine has an established safety record and has become a standard of veterinary care for dogs at high risk of rattlesnake bites. It is manufactured by Hygieia Biological Laboratories which has specialized in making veterinary vaccines since 1991. Every serial is individually inspected and tested before being released for sale. The vaccine was licensed for sale by the State of California in 2003 and became conditionally licensed for national sale by the USDA in 2004. It was listed in the AAHA 2006 canine vaccination guidelines as being presumably effective. The vaccination is highly recommended by VPI, the largest pet insurance company in America, for dogs at risk. Over 500,000 doses have been used in over 100,000 dogs since 2003. The vaccine is used in over 4,000 veterinary hospitals nationwide.
Adverse effects are reported in fewer than one percent of all vaccinated dogs. This rate is lower than that of some human vaccines. The most common side effect is a small granuloma (lump) at the injection site. This lump typically doesn’t bother the dog and will usually resolve without treatment in about two to four weeks. Treatment of injection site reactions can be accomplished by applying a hot moist compress on the injection site for 15 minutes several times per day until resolved. In about one in 300 vaccinations, the dog will develop a sterile abscess at the injection site that may need veterinary treatment. Ensuring the vaccine is deposited fully into the “dead space” between the subcutaneous fat and underlying muscle reduces this incidence of injection site reactions. Systemic reactions, similar to flu like symptoms, are reported in fewer than one in 3,000 vaccinations and typically self-resolve in two to three days. Other systemic side effects are reported at fewer than one in 15,000 vaccinations, don’t appear to have any particular pattern, and are so rare that many could be unrelated to vaccine use. About one third of these systemic side effects occurred in dogs with a prior history of adverse reactions to vaccines. As with any vaccine, anaphylactic reactions are possible but are estimated at fewer than one in 250,000 injections. In the event of an anaphylactic reaction, immediately initiate appropriate therapy with epinephrine or other anaphylactic drugs.
Though no vaccine is effective 100% of the time, there is both laboratory and field evidence indicating a fairly reliable level of effectiveness with Rattlesnake Vaccine. A 2006 survey of 720 veterinary clinics found 90% of clinics, which had treated vaccinated dogs for snake bite, rated the vaccine as working “well” or “very well”. Another 5% of clinics reported “mixed results”. About 3% of clinics surveyed could see no benefit from the vaccine and 2% chose to reserve judgment until they had treated more vaccinated dogs for snake bite. This was a nationwide survey so it strongly suggests cross protection against a wide variety of rattlesnake species. Benefits reported from veterinary clinics included a delay of onset of symptoms, less severe symptoms, less pain, less treatment needed or no treatment needed, lower mortality rates, and faster recovery times with little or no necrosis.
The vaccine has shown evidence of significant snake species cross protection in the field and may provide various levels of protection against the most common species of American rattlesnakes and copperheads. The best protection has been reported from bites from the Western diamond back rattlesnakes and Western rattlesnakes. The vaccine has also been reported to have protection against the Pygmy, Massasauga, Sidewinder, and Timber rattlesnakes and copperheads. The vaccine has been reported to have limited protection against the Eastern Diamondback rattlesnake. Red Rock Biologics says that this vaccine will not protect against the Mojave rattlesnake, coral snakes, or cottonmouth snakes.
None of the typical treatments for snake bite are contraindicated with this vaccine. Veterinarians can still use antivenin, steroids, antihistamines, and fluids in snake bite treatment if necessary. There are no horse or sheep proteins in rattlesnake vaccine. Red Rock Biologics recommends that vaccinated dogs be monitored for 24 hours post-bite to monitor whether the antibodies in the dog’s system are enough to neutralize the rattlesnake venom or the dog will need additional care. Antibiotics may be necessary to treat secondary infection from snake bite puncture wounds.
Vaccinated dogs, when bitten by rattlesnakes, will typically present with less severe symptoms and recover more quickly with little or no necrosis. Snake bites in vaccinated dogs are sometimes so mild that they are often initially mis-diagnosed as bug bites. Even though many dogs will have enough protection from the vaccine to recover from snake bites quickly with little or no veterinary treatment, Red Rock recommends that a rattlesnake bite should still be treated as a veterinary emergency so that a veterinarian can evaluate the pet for special circumstances. Sometimes dog owners don’t know that their dogs have received multiple snake bites. The vaccine protection can be overcome with enough venom and special circumstances that may require additional veterinary care. These circumstances include smaller dogs, larger snakes, multiple snake bites to the same dog, bites into or near vital organs, dogs that do not respond as well to the vaccine, and the possibility that the snake bite may have been made by a snake species that rattlesnake vaccine has little or no protection against. In special circumstances, antivenin and/or supportive therapy may still be required. The vaccine itself is not antivenin, and not a treatment for a snake bite that has already occurred.
Client education should include reminding dog owners that vaccine reduces but does not eliminate all effects from snake bites. Though most dogs do much better when vaccinated, even vaccinated dogs bitten by rattlesnakes should be seen by veterinarians immediately because of the possibility of complex snake bite circumstances and secondary infection.