Venomous snakes in the United States include pit vipers (rattlesnakes, copperheads, and cottonmouths) and coral snakes.
Severe envenomation can cause damage to the bitten extremity, bleeding, and vital organ damage.
Venom antidote is given for serious bites.
Bites from nonpoisonous snakes rarely cause any serious problems. About 25 species of venomous (poisonous) snakes are native to the United States. The venomous snakes include pit vipers (rattlesnakes, copperheads, and cottonmouths) and coral snakes.
Of the roughly 45,000 snakebites that occur in the United States each year, fewer than 8,000 are from venomous snakes, and about six people die. Fatal snakebites are much more common outside the United States.
In about 25% of all pit viper bites, venom is not injected. Most deaths occur in children, older people, and people who are untreated or treated too late or inappropriately. Rattlesnakes account for about 70% of poisonous snakebites in the United States and for almost all of the deaths. Copperheads and, to a lesser extent, cottonmouths account for most other poisonous snakebites. Coral snakebites and bites from imported snakes are much less common.
The venom of rattlesnakes and other pit vipers damages tissue around the bite. Venom may cause changes in blood cells, prevent blood from clotting, and damage blood vessels, causing them to leak. These changes can lead to internal bleeding and to heart, respiratory, and kidney failure.
The venom of coral snakes affects nervous system activity but causes little damage to tissue around the bite. Most bites occur on the hand or foot.