July 1, 2013
By Rachel Griess
Rattlesnakes emerge with summer, making this the right time for Colorado State University emergency veterinarians to research the perplexing effects of venom in the bloodstreams of snakebitten dogs.
“I find snake venom to be absolutely fascinating because every animal reacts differently,” said Dr. Raegan Wells, an emergency and critical-care clinician at CSU’s James L. Voss Veterinary Teaching Hospital.
“Depending on the size of the snake, the type of bite, the amount of venom, and characteristics of the patient, bites can result in minor to severe health issues,” she said. “These health problems could include hemorrhage, kidney and heart toxicity, muscle death, complete dysfunction of the nervous system, and even death.”
Wells has launched a clinical trial at the CSU Veterinary Teaching Hospital to better understand how venom works, particularly how it triggers potentially fatal effectswhen it enters the bloodstreams of victims. Her goal is to help snakebitten dogs in the trial, while also gathering crucial information that could improve venom therapies in both pets and people.
Each summer, the CSU Veterinary Teaching Hospital treats about 40 dogs with snakebite wounds, and 95 percent of these patients survive.
Yet even with a high survival rate, the venom can lead to significant pain and suffering in its victims. CSU veterinarians hope to improve bite treatment for faster recovery, fewer side-effects, and fewer lingering health concerns. Wells said she is also interested in longer-term therapies that might be developed with better knowledge of venom and its clotting mechanisms.
“Through this initial trial, we hope to understand venom’s impact on clotting function,” Wells said. “The big dream here is not only to improve treatment, but to also develop ways to utilize the venom therapeutically.”
Snakebitten dogs admitted to the Veterinary Teaching Hospital’s Urgent Care and Critical Care Unit this summer are eligible to participate in Wells’ study.
Up to 20 dogs accepted for the pilot study will receive treatment with a relatively new and notably effective antivenom formulation. The CSU vet hospital is the first veterinary hospital in northern Colorado to offer this particular antivenom, known as F(ab')2. A similar formulation of the antivenom, donated by Veteria Labs, is currently in clinical trials with humans.
Antivenom – the only treatment that will neutralize toxins found in rattlesnake venom – is made in a process that begins with “milking” venom from snake fangs. The venom is injected in small amounts into animals, often sheep and horses. This triggers an immune response and buildup of venom-fighting antibodies in a donor animal’s bloodstream. Blood then is drawn from the donor, antibodies are extracted, and antivenom formulas are purified for use in bite victims.
Antivenom works, in part, by interrupting the potentially fatal imbalance in blood clotting that occurs when venom enters a victim’s blood.
In the CSU clinical trial, Wells will analyze blood clotting in bite victims with a technology called thromboelastography, which assesses coagulation speed, strength, and breakdown.
Like other work in the CSU College of Veterinary Medicine and Biomedical Sciences, research results may be “translational,” meaning the discoveries could help improve medical treatments for both animals and people. Wells is collaborating with colleagues at the University of Northern Colorado in the field of rattlesnake venom research.
CSU veterinarians urge outdoor enthusiasts to take precautions when venturing out with their dogs.