Diseases & Conditions
While there are about 3,000 species of snakes in the world, only 10 percent of them are poisonous. Venomous snakes come in all sizes, from the tiny desert vipers to the king cobra, growing up to 16 feet long; a king cobra, when angered, can rear up and stand as tall as an adult. While there are many folk methods to quickly determine if a snake is poisonous, such as counting the rows of scales, there is no practical way to tell the poisonous from the harmless.
The highest death rates from snakebite in the United States are reported from Arizona, Florida, Georgia, Texas, and Alabama, in that order. There are only four varieties of snakes in the United States that are poisonous: the rattlesnake, copperhead, water moccasin, and coral snake, but they are found throughout the country. Of the 115 species of snakes in this country, only 20 are dangerous, including 16 species of rattlesnakes. Rattlers account for about 65 percent of the venomous snakebites that occur in this country each year, and for nearly all of the nine to 15 deaths.
The water moccasin is found throughout the southwest, the Gulf states, and the Mississippi valley as far north as southern Illinois. The copperhead is found throughout the country, especially in North and South Carolina, West Virginia, Pennsylvania, Missouri, Oklahoma, Arkansas, and Illinois. Rattlesnakes are found throughout the continental United States. The coral snake is associated with the South.
Despite the long history of snakebites and their treatment, the problem of how to deal with snakebites remains controversial. More than 200 different ﬁrst aid procedures for snakebite have been recommended by various experts, but the emphasis on treating snakebite should be to get prompt medical care. First aid should never be considered to be a substitute for antivenin.
Medical experts disagree about the best way to manage poisonous snakebites. Some physicians hold off on immediate treatment to observe the child to gauge a bite’s seriousness. Some doctors prefer to surgically treat tissue around the bite. But most often, doctors turn to antivenin as a reliable treatment for serious snakebites.
Antivenin is derived from antibodies created in a horse’s blood after the animal is injected with snake venom. Rapid treatment with an antivenin can help a snakebite patient regardless of whether or not the bite would have been fatal. Without antivenin treatment, hospital stays for venomous snake bites last about twice as long.
The venom of all snakes in the Crotalidae family (rattlesnakes, copperheads, and water moccasins) contains similar poisons, and all can be treated with antivenin. The bite from the eastern coral snake requires a separate antivenin, and there is no antivenin for the western coral snake.
In humans, antivenin is administered either through the veins or injected into muscle. Because antivenin is obtained from horses, snakebite patients sensitive to horse products must be carefully managed. The danger is that a child could develop an adverse reaction to the antivenin or even a potentially fatal allergic condition called anaphylactic shock.
First aid In recent years, fewer experts have been recommending invasive types of ﬁrst aid such as making incisions over the bite wound. Many health-care professionals embrace just a few basic ﬁrst-aid techniques. According to the American Red Cross, these steps should be taken:
1. Wash the bite with soap and water.
2. Immobilize the bitten area and keep it lower than the heart.
3. Get medical help without delay. Some medical professionals, along with the American Red Cross, cautiously recommend two other measures:
4. If a snakebite patient cannot reach medical care within 30 minutes, a bandage wrapped two to four inches above the bite may help slow venom. The bandage should not cut off blood ﬂow from a vein or artery. It should be loose enough that a ﬁnger can slip under it.
5. A suction device may be placed over the bite to help draw venom out of the wound without making cuts. Suction instruments often are included in commercial snakebite kits.
Antivenins have been used for decades and are the only effective treatment for some bites. While they have a fairly good safety record, they sometimes cause life-threatening reactions.
Children previously treated with antivenin for snakebites probably will develop a lifelong sensitivity to horse products. To identify these and other sensitive patients, hospitals typically obtain a record of the child’s experience with snakebites or horse products. But some people with no history of such exposures may have become sensitive through contact with horses, or possibly exposure to horse dander, and not know they are sensitive. Others may be sensitive without any known or remembered contact with horses.
This is why hospitals also perform a skin test that quickly shows any sensitivity. Some hypersensitive patients may even react severely to the small amount of antivenin used in the skin test. Some children with positive skin tests can be desensitized by gradually administering small amounts of antivenin.
Newer kinds of antivenins derived from sheep are under study now and show some promise, according to the U.S. Food and Drug Administration. Progress has been slow due to low demand and the small number of venomous bites a year.
By taking a few precautions, it’s possible to lower the risk of being bitten. Children should:
• leave snakes alone. Many people are bitten because they try to kill a snake or get a closer look at it.
• stay out of tall grass unless they wear thick leather boots, and remain on hiking paths as much as possible.
• keep hands and feet out of areas they cannot see. A snake can strike half its length.
• be cautious and alert when climbing rocks.
• walk at least six feet around a snake they encounter when hiking or picnicking.