Snakebites classification

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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]

Classification

  • Two families of venomous snakes are native to the United States. The vast majority are pit vipers, of the family Crotalidae, which include rattlesnakes, copperheads and cottonmouths (water moccasins). Pit vipers get their common name from a small "pit" between the eye and nostril that allows the snake to sense prey at night. The vipers are generally considered to be the most advanced family of snakes since they possess a very sophisticated venom delivery system. Large tubular fangs are placed in the front of the mouth and they are hinged, allowing them to be folded back when not in use.
  • About 99 percent of the venomous bites in this country are from pit vipers. Some--Mojave rattlesnakes or canebrake rattlesnakes, for example--carry a neurotoxic venom that can affect the brain or spinal cord. Copperheads, on the other hand, have a milder and less dangerous venom that sometimes may not require antivenin treatment.
  • The other family of domestic poisonous snakes is Elapidae, which includes two species of coral snakes found chiefly in the Southern states. The Elapidae contains some of the world's most dangerous snakes including cobras, mambas and sea snakes. In North America, three species of elapids are found, the Eastern and Western coral snakes and the Yellow bellied sea snake. The coral snakes are relatively small snakes that spend most of their time underground. Their primary food is other snakes. Despite their small size and small fangs, their venom is extremely toxic. Coral snakes have small mouths and short teeth, which give them a less efficient venom delivery than pit vipers. People bitten by coral snakes lack the characteristic fang marks of pit vipers, sometimes making the bite hard to detect.
  • Though coral snakebites are rare in the United States--only about 25 a year by some estimates--the snake's neurotoxic venom can be dangerous. A 1987 study in the Journal of the American Medical Association examined 39 victims of coral snakebites. There were no deaths, but several victims experienced respiratory paralysis, one of the hazards of neurotoxic venom.
  • Some nonpoisonous snakes, such as the scarlet king snake, mimic the bright red, yellow and black coloration of the coral snake. This potential for confusion underscores the importance of seeking care for any snakebite (unless positive identification of a nonpoisonous snake can be made).
  • The bites of both pit vipers and coral snakes can be effectively treated with antivenin. But other factors, such as time elapsed since being bitten and care taken before arriving at the hospital, also are critical.

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