Snakebite Overview continued...
- The elapid family includes the cobras; the mambas; the kraits (Bungarus) of Asia; the coral snakes (Micrurus) of the Americas; and the Australian elapids, which include the coastal taipan (Oxyuranus scutellatus), tiger snakes (Notechis), king brown snake (Pseudechis australis), and death adders (Acanthophis). Highly venomous sea snakes are closely related to the Australian elapids.
- The viper family includes the rattlesnakes (Crotalus) (Western diamondback rattlesnake and timber rattlesnake); moccasins (Agkistrodon); and lance-headed vipers (Bothrops) of the Americas; the saw-scaled vipers (Echis) of Asia and Africa; the Russell's viper (Daboia russellii) of Asia; and the puff adder (Bitis arietans) and Gaboon viper (Bitis gabonica) of Africa.
- Most species of the most widely distributed and diverse snake family, the Colubrids, lack venom that is dangerous to humans. Some species, however, including the boomslang (Dispholidus typus), twig snakes (Thelotornis), the Japanese garter snake (Rhabdophis tigrinus), and brown tree snake (Boiga irregularis), can be dangerous. Other members of this family, including American garter snakes, kingsnakes, rat snakes, and racers, are harmless to humans.
Bites by venomous snakes result in a wide range of effects, from simple puncture wounds to life-threatening illness and death. The findings following a venomous snakebite can be misleading. A victim can have no initial significant symptoms, and then suddenly develop breathing difficulty and go into shock.
Signs and symptoms of snake poisoning can be broken into a few major categories:
- Local effects: Bites by vipers and some cobras (Naja and other genera) are painful and tender. They can be severely swollen and can bleed and blister. Some cobra venoms can also kill the tissue around the site of the bite.
- Bleeding: Bites by vipers and some Australian elapids can cause bleeding of internal organs such as the brain or bowels. A victim may bleed from the bite site or bleed spontaneously from the mouth or old wounds. Unchecked bleeding can cause shock or even death.
- Nervous system effects: Venom from elapids and sea snakes can affect the nervous system directly. Cobra (Naja and other genera) and mamba (Dendroaspis) venom can act particularly quickly by stopping the breathing muscles, resulting in death without treatment. Initially, victims may have vision problems, speaking and breathing trouble, and numbness.
- Muscle death: Venom from Russell's vipers (Daboia russellii), sea snakes, and some Australian elapids can directly cause muscle death in multiple areas of the body. The debris from dead muscle cells can clog the kidneys, which try to filter out the proteins. This can lead to kidney failure.
Eyes: Spitting cobras and ringhals (cobralike snakes from Africa) can actually eject their venom quite accurately into the eyes of their victims, resulting in direct eye pain and damage.