Fully Vetted: Treating snake bites in pets

Published 10:00 pm Tuesday, May 16, 2017

’Tis the season for snake bites in Western North Carolina. I have already treated several pets with snake bites this spring. 

There are many species of snakes in our area, but only two that are poisonous: the Copperhead and the Timber Rattlesnake. Copperhead bites are more common than rattlesnake bites. Copperhead venom is also less potent than rattlesnake venom. Although severe systemic effects are possible from either type of bite, copperhead bites are less likely to result in severe illness or death.

The primary purpose of snake venom is to immobilize prey and pre-digest tissue. Chemicals in the venom cause cell death, break down the walls of blood vessels, and inhibit the blood’s ability to clot.

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Multiple factors affect the severity of a snake bite. The amount of venom injected into the victim is a major factor. Snakes that bite defensively tend to inject less venom than those that bite offensively. Younger snakes often have more venomous bites than older snakes. 

The size of the victim is also significant; smaller pets are more likely to suffer more severe consequences.  The location of the bite and the time elapsed between the bite and medical treatment also affect the prognosis.

Snake bites may difficult to detect due to overlying hair. Bites are immediately painful, and may be identified by the presence of puncture wounds. Swelling is usually prominent around the bite, although it may not be noticeable for several hours. Swelling may increase for up to 36 hours. Bruising and skin discoloration may also be present. Circulatory and clotting problems may occur immediately or may have a delayed onset. Nausea, salivation, lethargy, muscle tremors, and lymph node pain and swelling may also occur. As time progresses, the region surrounding the bite may become darkly discolored, and affected skin may slough off. This process may progress for several days.

Pet owners commonly ask about first aid for snake bites. Many methods have been suggested, but none have proven to help. Cold packs, hot packs, tourniquets, alcohol, cutting, and suction should be avoided. The affected area should be kept below heart level, and the pet should be seen by a veterinarian immediately so that medical therapy can be started as early as possible.

Veterinary care begins with a physical examination and an assessment of the bite wound. Bloodwork helps to determine the severity of envenomation. Antivenin is the only specific therapy available. It is expensive and carries a risk of adverse reaction, so its use depends upon the severity of envenomation and the time that has elapsed since the bite.

The remainder of therapy is based on supportive care, pain control, and wound care. IV fluids are often necessary for circulatory support. Oxygen therapy may be necessary in cases of facial swelling. Long-term wound care may be required. 

Symptoms of envenomation may be delayed for 12 hours or more, so even if a snake bite appears mild, immediate veterinary attention and close monitoring are strongly recommended to ensure the most favorable prognosis.

Dr. Kelly Sulik owns and operates Animobile Mobile Veterinary Services in Tryon, N.C. She can be reached at animobiledvm@gmail.com.