The warm weather months of April through September are the most common time for snakebites.
The warm weather months of April through September are the most common time for snakebites. (Bridget Edgren Courtesy photo)

What should I do if my dog is bitten by a snake?

You should assume it's poisonous and seek veterinary attention as soon as possible. First aid for rattlesnake bites is aimed at reducing the spread of venom in the body. If possible, you should carry the dog rather than letting him walk and immobilize the part of the animal that was bitten. But do not place a tourniquet or ice pack on the limb, because keeping all the venom in the bite area may cause severe muscle damage.

Will my dog die from a rattlesnake bite?

The vast majority of pets who are bitten by a snake will survive, but medical attention is vital to ensure the best outcome. Snakebites are a complex problem. The severity and type of damage done by venom depends on several factors. One is the species of snake involved. Of the 120-plus U.S. species of snakes, 20 are considered venomous. North American venomous snakes can be divided into two families: Crotalidae include rattlesnakes, copperheads and cottonmouths. Elapidae include coral snakes.

The eastern and western diamondback rattlesnakes account for most venomous snakebites and for almost all deaths. Copperheads have the least potent venom. Coral snakes are an infrequent cause of envenomation. Here in Colorado the most common venomous snake is the Prairie rattlesnake whose venom is not as potent as the diamondback's.

Another factor is the amount of venom injected. Twenty to 25 percent of rattlesnake bites are dry. Younger snakes can have more potent venom than older snakes and snakes that have just come out of hibernation can inject more venom through a bite than those later in the season. Most bites occur in the warmer months, April through September when snakes are active.

Other factors that determine severity of damage is where the dog is bitten -- face and neck are usually worse than those on feet or limbs -- the size, age, and health of the dog, and the dog's own susceptibility to the venom.

What are the signs of snakebites?

The clinical signs depend on the species of snake, the amount of venom injected, the depth of bite, and the size of the victim. With bites that contain no to little venom, clinical signs will consist of minimal swelling and a lack of systemic signs. With moderate to severe envenomation, you can see severe swelling around the bite. This swelling may occur immediately or it may take up to 30 to 60 minutes. The swelling can then spread rapidly and become very painful.

You can also see redness, bruising, bloody discharge from the fang marks, and tissue death. The fang marks may not always be visible due to the severe swelling. The venom of poisonous snakes contain toxic proteins that can produce not only local tissue destruction but also systemic effects. These include lethargy, weakness, hypotension (low blood pressure), bleeding or clotting disorders, and shock.

What is the treatment for snakebites?

Treatment involves local wound treatment, fluid therapy to counter potential hypotension (low blood pressure) or shock, administration of antivenin to help decrease the overall amount of swelling and prevent further progression of systemic signs, antibiotics to help prevent infection, and pain medications.

Is the rattlesnake vaccine effective?

There have been no controlled studies of efficacy performed on this vaccine. There is only anecdotal evidence suggesting that it might be effective. However, since we can never know the amount of envenomation, it is difficult to properly evaluate these observations. Regardless of vaccination status, owners should seek immediate veterinary care if their dog is bitten. Owners should not expect the vaccine to "protect" their pet.

VCA All Pets Animal Hospital is a full service veterinary practice seeing general medicine and emergencies 24 hours a day, 7 days a week. All Pets has been part of the community since 1972 and is accredited by the American Animal Hospital Association. Doctors provide care to dogs, cats, ferrets and pocket pets. Services include wellness care, preventative care, general and advanced dentistry, surgery, X-ray, laboratory, boarding, grooming and acupuncture. Visitvcaallpetsboulder.com or go to Facebook.com/AllPetsAnimalHospitalBoulder