A SNAKE IN THE GRASS

A new vaccine is now available which can immunize your dog against the effects of rattlesnake venom. The new vaccine is classified as a toxoid. The weakened or diluted venom from the rattlesnake is administered in two doses a month apart and should be boostered annually. The toxoid stimulates the body to form antibodies, which inactivate the venom in the victim's body. The consequences of being bitten by a rattlesnake are directly proportional to the amount of venom injected into the victim. Adult rattlesnakes can control the amount of venom that is released when biting. The more fearful or angry the snake, the larger the amount of venom released. While it is true that the venom of baby snakes is more concentrated and therefore potentially more lethal, the volume of venom in these babies is much smaller than in the adults. Even though the baby rattlers release their entire amount of venom with each bite, the total dose received is often less than their adult counterparts'. The fact that victims of rattlesnake bite can receive variable amounts of the toxins explains why we sometimes see survivors. Interestingly enough, these survivors become more efficient at surviving subsequent bites, even when exposed to higher doses! The explanation is that the initial sublethal dose of venom allowed their immune system to become more adept at producing the antibodies, which protect them during subsequent exposures. The vaccine attempts to simulate nature in the same way.

Until now, the only therapy available for the treatment of rattlesnake bites has been the administration of anti-venom. Anti-venom is actually hyper-immune serum and is produced by injecting small amounts of venom into horses. These "production animals" produce large amounts of antibodies, which are then harvested from the blood and concentrated as the anti-venom. It is important to understand that the anti-venom is only useful in countering the effects immediately after an individual is bitten. On the other hand, the toxoid vaccine prepares the individual in advance to be capable of producing the antibodies to protect itself.

Another disease where a toxoid has been very useful is in the prevention of tetanus. Horses get tetanus more frequently than any other domestic animal, by nature of the fact that the bacteria that produce the toxin that causes the symptoms of tetanus is a normal inhabitant of their intestinal tract, and is shed in the horse droppings. In addition, the nails used to secure horseshoes produce deep puncture wounds in the hoof, which allow the bacteria ready access to the horse as it walks through the abundant feces it has eliminated. Once the bacteria secure their spot deep in the wound they can produce the toxin that will make the horse very sick.

In dogs and cats, one of the most common skin diseases occurs as an allergic reaction to the bites of fleas. The condition manifests itself as loss of hair, redness and scabs at the base of the tail. The actual allergy is not to the flea's wing or toe, it is specifically related to a reaction to the flea's saliva, or venom, that is injected into the wound produced by the flea bite. Although the condition is readily treated with anti-inflammatory drugs like cortisone and improved flea control, this would seem like an ideal situation for the preventative effects of a toxoid. However, efforts to produce the toxoid have failed due to the difficulty of actually harvesting the saliva from the flea!

I would strongly advise dog owners living in rattlesnake-infested areas to vaccinate their dogs with the new vaccine. Never has the old adage, "An ounce of prevention is worth a pound of cure" been more appropriate!