Overview of Snakebites from Pit Vipers to Dogs
Bites by poisonous snakes, also referred to as snake envenomization, affect over 150,000 dogs and cats per year in North America. In the United States, there are two primary families of venomous snakes, Crotalidae and Elapidae. The southwestern and southeastern United States have a greater incidence of snakebites due to a higher population of venomous snakes.
Crotalidae is the most prevalent family of poisonous snakes in the United States. These include rattlesnakes, water moccasins and copperheads. These snakes have broad triangular heads with elliptical pupils, prominent curving fangs and a deep pit located between the nostril and the eye. For this reason they are commonly called “pit vipers.” It is believed that pit viper account for approximately 99% of all venomous snake bites to pets.
Even though a venomous snake may have bitten your pet, not all bites contain venom. In fact, less than half of all snakebites result in signs associated with envenomation. The risk of snakebite toxicity is based on the type of snake, the size of the animal bitten and the amount of venom injected in the bite. The type, effect and amount of venom can vary with the age and type of snake and can even vary within families of snakes.
Pit viper venom is not yet fully understood and the toxicity of the venom varies from species to species. For example, copperhead venom is much less toxic than rattlesnake venom.
Most snakebites occur in large breed primarily outdoor dogs with the majority of bites located on the legs or head, especially the muzzle. Most bites occur during the spring and summer seasons. It is estimated that 90% of bites occur between April and mid October. Bites from these snakes are generally the result of aggressive or curious actions while playing in snake-infested areas.
What to Watch For
A common scenario is a dog that is in the woods, near a thick grassed area or by a wood pile that suddenly cries out after which you notice a swelling on the legs or muzzle.
Other signs include:
Tissue swelling is often worse 24 to 48 hours after the bite. Wound may drain and bleed for several days. Most snake bites require veterinary care.
Diagnosis of Snakebites from Pit Vipers in Dogs
Diagnosis is based on physical exam findings supportive of a recent venomous snake bite as well as the potential exposure to venomous snakes.
Blood work may be done to evaluate coagulation times on a blood sample taken from an affected animal. Prolonged clotting times can indicate exposure to pit viper venom.
Treatment of Snakebites from Pit Vipers in Dogs
With rapid treatment, most dogs with Crotalidae snakebites recover. Treatment varies depending on which species of snake was responsible for the bite as well as the signs of toxicity displayed by the dog.
The prognosis in a dog with a pit viper bite is generally good with prompt treatment. Copperheads are the least toxic and generally require time for skin wound healing but are not fatal.
The best way to prevent Crotalidae snakebites is to restrict access to Crotalidae infested areas. Snakes prefer to live in quiet and dark areas and woodpiles are popular nesting sites.
If a venomous snake bites your dog, it is unlikely that he will learn from the experience and he probably won’t voluntarily avoid snakes in the future. Future venomous snakebites may result in much more severe toxic signs and might even result in death.