HOUSTON CHRONICLE (Texas) 09 March 05 On the offensive to combat venom - New vaccine helps protect dogs against rattlesnake bites (Doug Pike)
Texas quail hunters this winter worried every time they dropped a pointer off a pickup that it might trip over a rattlesnake in the tall grass. A new vaccine for dogs eases some of that concern.
Rattlesnakes and their kin are found in almost every Texas county, according to Dr. Andy Price, the Texas Parks and Wildlife Department's reigning serpent expert. Perception of their relative abundance, he said, depends on how often you visit the snakes' habitat.
"Rattlesnakes don't do well where people are concentrated," he said.
Elsewhere, the state's various species (nearly a dozen) manage just fine. Their numbers have increased, too, behind back-to-back years of excellent range conditions statewide. Lush grasses and timely rain boosted populations throughout the food chain, especially among animals that feed on birds, small mammals and rodents.
Well-timed rainfall and lush vegetation for the past two years — we're off to another wet start in 2005 — triggered quail and rodent population spikes and, in turn, increased encounters with rattlesnakes.
It's impossible to know how many dogs were bitten in 2004. The state doesn't even keep tabs on how many people are struck. Even one bite is too many, however, if it was your dog at the hot end of those fangs.
The venom of a rattlesnake makes prey animals easier to swallow. In simple terms, its toxins turn muscle to jelly. The process is slower in animals as large as dogs or people, and any major damage from a rattlesnake hit usually is restricted to a small area around the strike area..
Being bitten isn't synonymous with envenomation and seldom is fatal, even for dogs. In fact, Price said, some 25-40 percent of rattlesnake bites are "dry," injecting no venom at all. Whether that is intentional on the snake's part (as a warning to animals the snake knows it cannot eat) or caused by the angle and impact pressure of a strike is not fully understood.
What is known is that there are no good rattlesnake bites, and nobody is more keenly aware of that than Drs. Jim and Dale Wallis, California veterinarians whose Red Rock Biologics developed a rattlesnake vaccine for dogs.
It was shortly after Dale's cat, Pumpkin, was bitten by a rattler that she first thought of creating a pet vaccine against the bites. When a second cat in the Wallis household was bitten, the research intensified.
Their finished product, based on the chemical characteristics of the Western diamondback's venom, was first licensed in California in June 2003. Already, more than 30,000 doses have been distributed in that state.
Approval to sell the drug nationally by the U.S. Department of Agriculture, which oversees medications for animals, came just two months ago.
Already, the company has received testimonials from pet owners whose dogs were spared expensive and agonizing recoveries by the drug. Last April, said Red Rock Biologics' product representative, Pete Wallis, a dog named Jet took a rattler's strike for its owner's child. Jet's owners had been offered the vaccine during a recent visit to their veterinarian but declined. Antivenom and subsequent after-care wound up costing thousands of dollars.
The vaccine costs about $25-$35 per dose in California, Pete Wallis said, and full protection is reached about 30 days after the second injection. Dogs that live in areas where rattlesnake populations are highest should get boosters every six months or so, Pete Wallis said.
Dr. Jimmy Cox is one of a few local vets who carry the vaccine. A bird dog owner himself, he charges $20 per dose.
"I've had it a little over a month," Cox said. "I'm generally pretty skeptical, but I've vaccinated my own dog."
Cox said his concern with vaccines is the animals' reaction to them, which sometimes is worse than what the vaccine is designed to counter. With the rattlesnake vaccine, he said, dogs he has treated have shown no significant negative reactions.
"I look at it as cheap insurance," Cox said.
Insurance, but not a guarantee. Cox encouraged dog owners also to put their animals through desnaking clinics. Vaccine or no, every rattlesnake bite should be treated as a medical emergency. (Some of the deepest, potentially most dangerous bites may produce relatively minor visible symptoms while the venom does severe damage to underlying tissues.)
"The protection can be overcome," Pete Wallis said, by an unusually large snake or a heavy envenomation.
Also, Dale Wallis said, the vaccine is not effective against all rattlesnake species. The chemistry of each venom is slightly different, and those differences are critical to the vaccine's efficiency.
The Wallis' are not satisfied with their vaccine's protection against the Mojave rattlesnake or the Eastern diamondback. For most other species and their bites, including timber and pygmy rattlers, it provides good protection.
The Western diamondback is Texas' most aggressive and most common rattlesnake, Price said, but it isn't found around Houston. Southeast Texans are more likely to encounter the timber rattler. A genuine five-footer is big for either of Texas' most common species, and rattlers anywhere near that length carry enough venom to kill a large animal.
Size doesn't matter so much with rattlesnakes. They're all dangerous, but this vaccine for dogs should give bird hunters and pet owners some long-awaited peace of mind.
For more information, go to www.redrockbiologics.com.
New vaccine helps protect dogs against rattlesnake bites
New vaccine helps protect dogs against rattlesnake bites