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When Margarita, a 10-year-old basset hound, was bitten by a cottonmouth snake recently, her quick-thinking owner rushed the dog to the University of Florida's Veterinary Medical Center for treatment right away.
In doing so, Sandra Fields Seymour, Ph.D., A.R.N.P., a recently retired associate professor in UF's College of Nursing, and her husband, Larry, of Ocala followed a cardinal rule in preventing death or lasting tissue damage from snake bite in an animal: They sought immediate evaluation by a veterinarian.
Margarita, whose owners have now nicknamed her "Snake Bite Warrior," survived her bites and today appears no worse for the wear.
"It was an unfortunate situation where dog and snake were each doing what they were born to do, but with serious consequences for both," Seymour said.
Margarita arrived at the UF VMC on July 3 around midnight with two strike wounds. Soon her signs of swelling, or envenomation, had greatly increased.
"Margarita had obviously received enough venom to cause serious side effects," said Kate Ogawa, D.V.M., an intern in small animal medicine and surgery. Veterinarians quickly decided to administer antivenin - six vials, in fact.
"She also developed heart arrhythmias, which fortunately did not become severe enough to require treatment," Ogawa said. "We closely monitored Margarita's strike areas and swelling for signs of tissue death that would require surgery. She was lucky. Her wounds healed uneventfully, and she did not need further treatment."
The side effects of snakebite can vary greatly depending on the particular snake, and the dose of venom the animal receives, veterinarians say.Bites from rattlesnakes, cottonmouths and copperheads can result in severe tissue swelling, blood-clotting abnormalities, heart arrhythmias, organ damage and tissue death around the bite site.
Not all pets that are bitten by a venomous snake require antivenin, since occasionally pets will receive a dry bite, with no venom injected, but a prompt evaluation by a veterinarian is recommended.
Hospitalization may also be needed for veterinarians to monitor for heart arrhythmias as well as to provide fluid support, pain medication and frequent reassessment.
Although antivenin can be lifesaving, how much to give is a judgment call, since the amount of venom contained in a snake's bite is unknown. In general, however, the more antivenin received quickly, the better, veterinarians say.
"Unfortunately, antivenin is quite expensive and can be cost prohibitive for some owners to administer several vials," Ogawa said. "Additionally, antivenin for veterinary medicine is currently not being manufactured in this country."
Thanks to the efforts of UF snake envenomation expert Michael Schaer, D.V.M., UF was able to procure an antivenin product from Mexico. That particular product was manufactured for people, but UF was able to obtain permission for animal use from the Food and Drug Administration.
Reactions to antivenin are possible also, which is another reason why victims of snakebite need to be monitored carefully for several days after the antivenin is administered.
"I would urge people to protect themselves as much as possible from venomous snakes, and as such I cannot recommend killing the snake for identification," Ogawa said. "If the snake is already dead, bringing it in for positive identification can help, as some snakes have more potent venom than others. Dead snakes still can cause envenomation, so extreme care should be taken when moving the body.
The antivenin contains antibodies against the venom of most snakes, so knowing exactly what snake it was is not nearly as important as getting treatment as soon as possible."
