Pit Viper Bite Poisoning in Cats

The location where the cat is bitten by the snake matters greatly. Bites that occur on the body near the heart are often fatal. Each bite differs in venom volume and toxicity, making it hard to determine the onset of symptoms. Pit viper venom interferes with the body's ability to clot blood, which can cause a bitten cat to bleed out, or cause its blood to coagulate too rapidly, causing organ failure. Most bites occur on the limbs, neck or head. Some pit viper bites may inject neurotoxins only, which slowly paralyze the cat and eventually stop the respiratory system. Any snake bite is a medical emergency requiring immediate veterinary attention.

Pit vipers are venomous snakes found in many parts of North America. They have a “pit” between their eyes and nostrils which leads to their name. They are the largest venomous snakes, ranging from four to eight feet in length. They include rattlesnakes, copperheads, and cottonmouths. It is estimated that, on average, 150,000 cats and dogs are bitten by these snakes every year. The snake does not always release venom in its bite, only doing so when threatened. Approximately three out of four bites are venomous.

Symptoms may progress rapidly at any time after a bite has occurred. If one or two bleeding puncture wounds are noted and they become inflamed or begin to hemorrhage, venom has likely been injected into the cat. Other symptoms to watch for:

• Extreme pain
• Dizziness
• Nausea
• Vomiting
• Diarrhea
• Weakness
• Shallow or labored breathing
• Abnormally low blood pressure
• Bleeding, bruising or slow blood clotting
• Restlessness
• Drooling
• Abnormal gait
• Spreading local tissue damage
• Shock

If you witnessed the snake bite or you suspect it has happened, keep the cat laying down and immediately transport it to a veterinary clinic or animal hospital. Do not wait to see if symptoms manifest. The cat’s life is at stake. 

Even just the presence of a cat may be enough of a threat to a pit viper for it to bite. If you are in an area where pit vipers are known to live, it is best to keep close tabs on your cat. If cats are allowed to roam in habitats where pit vipers are present, there is a risk of pit viper bites. The toxic venom from the snake's bite can destroy red blood cells in the cat, paralyze it, or cause the blood in the bloodstream to coagulate. The venom also kills body tissue, solidifying a snake bite as a severe threat to a cat’s life. 

Before arriving at the veterinary clinic or animal hospital, call ahead to verify if they have pit viper antivenin on hand. They may have to obtain some from a human hospital or you will be referred to a nearby facility that carries the antivenin. Not all centers carry antivenin because it is expensive and does not have a long shelf life. 

Securing antivenin before a diagnosis is confirmed is the best route, as the cat has limited time before organs will begin to shut down. If the snake has been killed, bring it along but be sure not to touch the fangs, as they remain venomous after death. If the snake is alive, do not attempt to bring it. If the situation allows a quick picture to be taken, this can prove to be helpful in identifying the snake. 

The veterinarian will attempt to differentiate the snake bite from other common occurrences, such as spider bites, fractures, allergic reactions to insect bites, and stings or abscesses. If the snake bite does not have obvious fang puncture marks, and is instead horseshoe shaped, the snake that bit the cat may not be a venomous pit viper. Veterinary care is still necessary as any snake bite can lead to infection.

There are certain supportive treatments that can keep the cat stable for a longer period of time while waiting for antivenin to be obtained. A cat who has received proper supportive care has a better chance of surviving until proper treatment is administered. 

Corticosteroids 

The first two hours after a bite has occurred is the ideal time window for treatment to be administered. If there is a delay on receiving an antivenin, applying corticosteroids can prolong this initial period of time and keep disseminated intravascular coagulation (the rapid formation of blood clots) at bay. 

Supportive Care  

Both before and after an antivenin is given to the cat, keeping the cat calm and limiting its movement can prolong life. IV fluids can be used to boost blood volumes, especially if hemorrhaging has occurred. Oxygen can be supplemented to support the struggling respiratory system. 

Antivenin 

The only way to reverse the effects of a venomous pit viper bite is to administer the corresponding antivenin. Pit viper antivenin is readily available in parts of the United States where pit vipers are present. The dosage will be determined based on the amount of venom that has been injected, the size of the bite, and the size of the cat. Smaller animals tend to need larger doses because it takes less venom to shut down their bodies. Generally, one to two vials of antivenin will be administered. The first portion will be injected directly into the site of the snake bite. The rest of the antivenin will be given intravenously. The 24 hours after antivenin treatment will determine if the cat has responded favorably or not. If no shock is present and the cat is resuming activity, it may be discharged from the hospital. 

Antibiotics 

It is generally recommended that a cat who has experienced a snake bite should receive a broad spectrum antibiotic. This will prevent secondary bacterial infections from developing in the cat.

In the ten days after your cat has returned home, closely monitor it for infection or spreading tissue damage. This can occur, and become so severe that limb amputation is required. If your cat is bitten a second time by a pit viper, it may develop some immunity and resistance to the effects of the venom. 

There are vaccines available that can help your cat built antibodies against snake venom, which buys you more time in the event of an emergency. If you live in an area pit vipers are known to inhabit, learn the snakes that live around you. It may be best to keep cats indoors to prevent bites from happening.