Snake Bites in Pets

What you should know
By Katie Gibson, DVM
It is summertime and you and your pets are spending a lot more time outdoors enjoying the pleasant weather. Well guess what, you’re not the only creatures enjoying the nice weather. Yes, about this time of year veterinarians begin to see dogs and cats come into the hospital for treatment of snakebites. Here are some things that you should know to help keep your pet safe from these slithery creatures.
First of all, not all snakes are venomous. There are many more species of non-venomous snakes in this area then there are venomous ones. Venomous snakes that your pet may be exposed to fall into two major categories: the crotalids and the elapids. Crotalids belong to the pit viper family and include snakes such as the copperheads, rattlesnakes, and water moccasins (also known as cottonmouths). These snakes have the classic triangular-shaped head, cat-like eyes, and tend to be heavy bodied. These snakes can be found across most of the North America. The elapids are the most deadly venomous snakes. Luckily, in North America the coral snake is the only member of this group. Coral snakes have red, white/yellow, and black banding and can usually only be found in Arkansas, Florida, Georgia, Louisiana, South Carolina, Texas, and the coastal planes on North Carolina.   I highly recommend looking at photographs or visiting your local nature center to be able to identify the venomous snakes in your area. In Western North Carolina the types of venomous snake that pets typically encounter are the copperhead and the rattlesnake, and for the purpose of this article, these are the types of snakes I shall focus on.
When a venomous snake encounters a human or a pet, its first instinct is to flee not to bite. The purpose of snake venom is to allow the snake to catch small prey items. It will use it for self-defense only when necessary. The venom that the snake produces is stored in sacs located behind the eyes. The snake can control how much is released into its hollow fangs and injected into its victim. This venom causes local tissue injury, coagulation disorders, and can affect the cardiovascular system and the respiratory systems. A venomous snake may or may not inject venom with every bite. A bite where venom is not injected is known as a “dry bite”. The size of the snake does not necessarily indicate how much or how little venom is injected. The snake has the ability to control how much venom is injected. Frequently smaller snakes will actually inject more venom than larger snakes because they fear for their life. 
How do you know if a venomous snake has bitten your pet? A dog or cat bitten by a venomous snake will be extremely painful where he/she is bitten. Dogs and cats can be bitten anywhere, but they are often bitten on the muzzle or on a limb. You may be able to see two puncture wounds from the fangs, but these wounds can be difficult to see. The most common finding that you will easily be able to detect is swelling around the bite site. The pet may be very weak and lethargic and there can be some vomiting, but these signs are not always present. Other things that can look similar to a snakebite are allergic reactions from insect stings, blunt trauma, an animal bite, or an abscess. If you are unsure if a venomous snake has bitten your pet it is best to contact a veterinarian. 
What should you do if a snake bites your pet? It is NOT necessary to kill the snake in order to identify it! If you can identify the snake, it is helpful, however, do not get close enough to the snake to put yourself at risk of getting bitten. Humans are at greater risk of being bitten by a snake if they are trying to harm it, so attempting to kill it can actually put you at greater risk of being bitten than if you let the snake slither off into the woods. In this area, the treatment for copperhead bites and rattlesnake bites is essentially the same so identification is not crucial. The next thing you should do is attempt to keep your pet calm and contact a veterinarian. Be aware that a pet will be very painful after being bitten. Use caution when handling your pet. The painful bite may cause your pet to snap at you or bite you when being handled. If you need to lift your pet into a car, a muzzle or wrapping the pet in a thick comforter may be necessary to keep you safe. Cats should be transported in a cat carrier or box if possible.
There are a number of treatments for snakebites that have fallen out of favor over the years, here are some things you should NOT do. Do not put any sort of tourniquet on your pet. Do not apply ice. Do not make any cuts into the skin and do not try to suck the poison out. Do not apply a compression bandage to the wound. These treatments can cause harm to your pet or harm to you. 
Once you get your pet to a veterinary hospital your veterinarian will advise you on the best tests and treatment for your pet based on his/her condition. Your veterinarian may want to look at a blood smear to help determine if it was in fact a venomous snake that bit your pet. Often, but not always, the red blood cells of a pet that was bitten will look spiky when viewed under a microscope. Since snake venom can cause a bleeding disorder, your veterinarian may want to test your pet’s clotting times. Other tests that may be performed include a CBC, a chemistry panel, a urinalysis, blood pressure, and an EKG. Your veterinarian will treat your pet based on how severely he or she is affected. Treatments may include pain medication, intravenous fluids, anti-histamines, steroids, antibiotics, and antivenin.   
Not all snakebites require antivenin. Antivenin is useful in cases where your pet’s clotting times are affected. The antivenin can help prevent bleeding disorders. Antivenin can also help reduce the amount of swelling. It is best if antivenin is administered within four to six hours once a pet is bitten. Pets can have a serious allergic reaction to antivenin. Your veterinarian will advise you if he/she thinks your animal would benefit from antivenin. Your veterinarian will take precautions to minimize the chance of an allergic developing if this product is administered. 
What is the prognosis for your pet if is bitten by a venomous snake? With the types of venomous snakes that are found in Western North Carolina it is rare for pets that receive veterinary attention to die from snakebites, but in some cases it does happen. The majority of pets will be uncomfortable and swollen for several days. The skin around the bite may become discolored and in some animals the skin will slough several days later. Most pets will stay in the hospital for observation for 12-24 hours and then go home with appropriate medications once they are deemed stable and their pain can be managed at home. More severe cases may require hospitalization for several days. If the skin around the bite does slough, additional veterinary care will be needed.   
What can you do to prevent your pet from being bitten by a snake? Venomous snakes can often be found basking in the sun, warming themselves on the side of asphalt roads in the evenings, and hiding under rocks and logs. Be vigilant if you are in an area where you expect to finds snakes and keep your pets on a leash when going for walks. Clear away logs, rocks, and debris from your property to discourage snakes from seeking refuge here. There are some snake repellants on the market that can be applied to your property as well. If you encounter a snake it is best to get your pets under control and freeze. Allow the snake to move away or change your route to avoid it. Treat all snakes as potentially venomous if you are unable to identify the type of snake it is.
If you encounter a venomous snake while hiking with your pet this summer I hope you will have a healthy respect for these amazing creatures and get to marvel in their beauty. However, if a bite to your pet does occur, contact your veterinarian so the appropriate care can be given to your pet.
Dr. Katie Gibson works as an emergency veterinarian at the Regional Emergency Animal Care Hospital (REACH) in Asheville, NC.