‘The Hundred Pacer’—A Walk on the Wild Side
It’s believed that after the victim is bitten, he or she will be able to walk only a hundred paces before perishing. In regions where the snakes may be more venomous, they are known as “fifty-pacers.” Deinagkistrodon acutus is a venomous pit viper found in Southeast Asia and known by many names: the Chinese moccasin, the sharp-nosed viper, the snorkel viper, and the “hundred-pace viper” (“hundred-pacer.”)
Pit vipers are venomous snakes with a heat-sensing pit anteroinferior to each eye, elliptical pupils (cat’s eyes), and a single row of scales on their undersides—in contrast to nonvenomous snakes, which have no facial pits, round eye pupils, and 2 rows of scales on their undersides. All snakes are “cold-blooded” reptiles—that is, they maintain their body temperature approximate to the environment. Their forked tongues and highly developed nostrils contain receptors that can “taste” or detect odors in the air by focusing substances on the Jacobson’s organ (highly developed olfactory tissue) located in the palate. This helps to locate prey—primarily small animals and birds.
Moccasins inject their venom through hollow, movable (retractable) fangs, and, as with all venomous snakes, not all bites contain venom; these nonvenomous bites are known as “dry bites.” To the consternation of some, venomoids are venomous snakes that have had a surgical procedure to render them incapable of administering venom with a bite (usually the removal of the venom gland). These surgically altered snakes are considered less dangerous when kept in captivity.
Snake bites are typically occupational hazards in countries where workers such as fishermen, farmers, plantation workers, and herders come into contact with snakes. In addition, many workers from Asian and South Asian countries live in outdoor habitats and are exposed to nocturnal snakes while sleeping. It’s estimated about 5.4 million people are bitten annually, with approximately 81,000-138,000 deaths per year—and with three-fold as many amputations and disabilities resulting from the bite. While most snake bites occur on the extremities due to attempted handling of a snake or walking in an infested area, there have been cases of penetrating ocular injury. In one such case, the victim crawled along a hillside when bitten on his right eye.
The initial symptoms after a bite from a pit viper are usually pain and swelling around the bite, with physical signs of fang marks, hemorrhagic vesicles, and tenderness at the bite site. Patients who present to the emergency department may have a history of nausea, vomiting or diarrhea, and loss of consciousness as their blood pressure drops.
Some snakes, such as those in the Elapid family (e.g., Australian death adders, African mambas, and Asian coral snakes), produce venoms containing neurotoxins that cause paralysis and death by respiratory failure. Other snakes in the Crotalid family, such as the hundred-pace viper, create venoms containing hemorrhagic and proteolytic components, producing bleeding disorders and tissue death. Snake venom proteins are the mechanism whereby animals kill or arrest their prey.
Immobilizing the bitten limb and keeping the victim still helps reduce venom spread. Antivenom is used to neutralize toxins. Several countries produce specific antivenoms for individual snake species (see WHO Regional Office for South-East Asia). However, with antivenom administration, there is always the risk of an allergic reaction. While snakebites are less commonly fatal in the U.S. than in the rest of the world, they are nevertheless of considerable medical importance and should be identified so that the appropriate medical care can be rendered expeditiously.
Adapted with permission from Lily Robinson and the Art of Secret Poisoning
For more information on snakebites and treatment, see the following links
Snakebite envenoming (who.int)
Control of Neglected Tropical Diseases (who.int)