Snakebite

By Jean Sabatelli, AnimalForum.com staff
Copyright 1999, Jean Sabatelli. Used with permission.

A dog's natural curiosity can get him in real trouble, and dogs with a strong prey drive or chase instinct are even more susceptible than most. Anywhere around the world a dog can run into a poisonous snake. Here in the United States there are approximately 15,000 dogs and cats bitten by poisonous snakes annually. The highest envenomation fatality rates occurred in Arizona, Georgia, Florida, Alabama, South Carolina and Texas. In dogs, 70-80 percent of bites occur on the face and head, and 20-30 percent occur on the legs, with only rare cases occurring on the body. Rattlesnakes account for 80 percent of dog envenomations, while cottonmouths, water moccasins and copperheads are responsible for the remaining 20 percent.

The poisonous snakes of the United States belong to three groups: pit vipers, elapids and colubrids. The pit vipers -- rattlesnakes, copperheads and cottonmouths -- cause more than 99 percent of venomous bites in the United States. Pit vipers are named for heat sensitive pits located between the eyes and nostril. Other characteristics of pit vipers are their triangular shaped heads, elliptical pupils, retractable fangs, and a single row of sub caudal plates. These snakes can strike at eight feet per second and may strike to a distance up to one-half their body length.

Numerous factors affect the severity of the snake bite. One of these factors is the amount of venom injected by the snake into the victim. In a typical feeding strike, 15-20 percent of the venom is released; 50 percent is released in a defensive strike; and up to 75 percent or more in multiple strikes. Not all snake bites result in death or severe medical problems due to the fact that 20 percent of the bites are dry bites where no venom is released, 30-35 percent are mild envenomations, and 45-50 percent are envenomations severe enough to be a medical emergency.

It is important to understand that you cannot wait to see how bad a bite is. You cannot tell how severe the envenomation is simply by looking. The amount and composition of the venom is determined by the species of snake, the time of year, the regenerated volume of venom, the age of the snake, aggressiveness of the snake, and the motivation and size of the snake. The quantity and the toxicity of the venom are perhaps the two most important factors affecting the severity of envenomation. Factors affecting the severity of envenomation of the victim include the body mass or size of the victim, the location of the bits, the length of time to an emergency clinic or hospital, the excitability of the patient, physical activity after the bite, type of first aid given, and medications administered.

A quick field diagnosis of snake bites involves seeing the punctures where the fangs penetrated the tissues, severe pain at the site of the bite, edematous swelling, ecchymosis (pinpoint bruises), nausea, weakness, severe hypotension and shock.

First aid do's and don'ts
The best and safest advice on first aid is to seek medical attention at an emergency clinic or hospital as soon as possible and keep the victim calm. Call ahead to allow the clinician to prepare the antivenin and to set up other emergency medications. Avoid medications of any type, but especially pain medication, tranquilizers, cortisone and/or DMSO. Do not use ice, tourniquets, alcohol, cut and suck techniques, or electrical shock devices. The Food and Drug Administration banned the use of electrical devices in 1990 for the treatment of envenomation of animals and humans.