Snake Bitten Pets


Various rattlesnake species are known to exist in southern California; the western diamondback is predominant. In California, over 800 people per year are bitten by rattlesnakes annually; similar data for animals is unknown but dogs and cats are nailed every year.

While some information regarding snake bites in dogs is known, little is known about cats affected by snake bites. Current treatment recommendations for cats are based on the literature for treatment pertaining to people and dogs. Because of the lack of studies in cats, it is uncertain if these treatment recommendations are appropriate. Even in dogs, where there’s data regarding treatment, treatment protocols are influenced heavily by expert opinion and anecdotal evidence. The purpose of this retrospective analysis is to review treatment regimen and outcome data of cats envenomated by rattlesnakes.

The Winn Feline Foundation supported a study which 18 cats were treated for suspected rattlesnake envenomation between January 2007 and August 2010 to an emergency referral clinic in southern California.

There were three fatalities and 15 cats survived (16% mortality rate). Two cases developed pelvic limb paresis three to four days post envenomation which was self-limiting (the cats recovered with minimal supportive care). There were no apparent adverse reactions to treatment with antivenom.

Cats were infrequent in presentation for snake bites at this emergency clinic as compared to dogs at the same clinic, of which there were 367 cases. Clearly dogs seem more curious about the snakes, where cats will scamper away, even up a tree. However, mortality was higher among cats. Most bites were on the forelimb. Cats can respond to snakebite treatment similar to that used in dogs and humans.

The toxins from the venom also cause a decrease in platelets and clotting factors, so excessive bleeding and bruising are common in bite victims. These lab values are monitored closely during hospitalization and generally start to improve within days.

With aggressive treatment, most rattlesnake victims will fully recover. A pet’s prognosis is based on the size of the pet, the location of the bite, and time from bite to treatment. Although some of these factors may be out of your control, there are things you can do to hasten your pet’s recovery.

What to do if a rattlesnake bites your pet:

  1. Keep him or her quiet and seek veterinary attention immediately.
  2. Do NOT cut open the wound to attempt to suck out venom.
  3. Do NOT apply a tourniquet.
  4. Stay calm and quietly remove your pet and yourself from the area where the snake is to prevent further injuries.

There are also ways to avoid bites as well.

Obviously, indoor cats rarely have a problem with snake bites.

Remember rattlesnakes are typically not aggressive and generally try to avoid contact with humans and pets. They only strike when startled or threatened. Snakes tend to be out more at night, so when taking nighttime strolls, keep pets on a leash. When out on the trail, stay on the trail, keep your pets leashed, and check out rest spots before you sit down. If you live in rattlesnake populated areas, snake-proof fences can be made using galvanized hardware cloth with a 1/4 inch mesh buried 6-inches deep and slanted outward at a 30 degree angle.

The Canine Rattlesnake Vaccine (Red Rock Biologics) comprises venom components from Crotalus atrox (Western Diamondback). The vaccine became available in the early 2000s as a means of preventing morbidity and mortality in dogs likely to be bitten by rattlesnakes.  Although there may be circumstances where a rattlesnake vaccine may be potentially useful for dogs that frequently encounter rattlesnakes, there remains little fact-based data to support the efficacy of the vaccine to date. Dogs do develop neutralizing antibody titers to C. atrox venom, but titers may vary and frequent boosters (4-6 months) may be required to maintain titers.  Vaccine costs are between $20 to $40 per injection. According to the manufacturer, rare vaccinated dogs have died following a bite when there were substantial delays (12-24 hours) in seeking treatment. According to the manufacturer, no new efficacy trials have been performed to verify efficacy.

The vaccine has been administered to over 100,000 dogs to date, and appears relatively safe, with less than 1% reported side effects.  The most common side effects have included sterile abscesses (1/300 injections) and injection site reactions or lumps (1/1,500), most of which resolve without treatment in less than a month.  Flu-like symptoms have been reported in 1/3,000 vaccinations which are reported to resolve in a few days.  Anaphylactic (allergic) reactions are estimated to occur in 1/250,000 cases.

Although the product is relatively safe, even vaccinated dogs bitten by rattlesnakes should be considered a veterinary emergency. This is due to the fact that 1) snake venom components vary with species and some (e.g., Mojave rattlesnake) may not be covered by the vaccine 2) antibody titers may be overwhelmed in the face of severe envenomation, and 3) an individual dog may lack protection depending on its response to the vaccine and the time elapsed since vaccination.