Animal Emergency Clinic of Central Texas

Most snakebites in the US (Texas has the highest number of reported bites annually) come from members of the Crotalidae family, also known as the "pit vipers". These would be varieties such as Rattlesnakes, Water Moccasins, & Copperheads.

Severity of Venom Toxicity:

The most venomous of these vipers would be the Rattlesnake. They are responsible for the most fatalities in the US, annually. Second to them would be the Water Moccasin (also commonly referred to as "Cottonmouths"). Although they are less common, and less aggressive than Rattlesnakes these guys are dangerous because they do not give any type of warning comparable to the warning rattle of a Rattlesnake. Victims are often caught off guard by them. Last of all would be Copperheads. While they are responsible for the most reported bites, their venom (in general) is considered to be "sub-lethal". Usually it is not enough to kill most dogs or cats. You may still, however, experience a medical emergency if your animal is struck by one. We urge you to seek medical attention regardless of the type of snake.

Little Known Venom Facts:

• Juveniles have more concentrated venom than adults.

• Venom tends to be less potent in the fall.

• The volume of venom increases with time since the snake's last meal.

How Venom Works:

The cardiovascular system is the primary target of this toxin. It attacks the cells that line the blood and lymphatic vessels, the heart, and various other body cavities. Immobilization of prey is achieved by damaging these cells in the victim, allowing plasma to extrude and blood to go into surrounding tissues and spaces (some know this as "bleeding out"). This leads to low blood volume and shock. In addition, since snakes do not chew their food they need enzymes in their venom to start the digestive process. This starts the breakdown of the prey's body prior to actual digestion.

Physical Symptoms Associated with Envenomation:

• Pain, bruising, swelling, and necrosis of tissue at/around the bite site

• Blood clotting defects (presence of mini hemorrhages on the mucous membranes)

• Decreased number of platelets in the blood (affects clotting times).

• Cardiovascular and respiratory distress

• Low blood pressure and high heart rate (together = "shock")

• Depression and/or lethargy

• Nausea and excessive salivation

Vaccination:

There is now a rattlesnake vaccine that can be effective to aid in treatment if given prior to exposure. If you are interested in details regarding this vaccine, you should contact your regular veterinarian to discuss it. It is, however, manufactured using only venom of the Western Diamondback Rattler and since both Eastern and Western varieties are common in Texas we still recommend antivenin and hospitalization in all cases.