SC8: Special Considerations

HISTORY AND EPIDEMIOLOGY

The incidence of snakebites worldwide is difficult to ascertain, as there is no systematic reporting mechanism. This fact, when combined with the variable degree of confirmation of snakebites, makes the estimation of an accurate number extremely difficult. Attempts have been made utilizing available data from case reports in the literature, hospital records, surveys, and existing reporting systems. Current estimates place the worldwide annual incidence of snakebites as high as 5.5 million.^11,36 Of these, roughly 50% are thought to be from venomous snakes.⁷ Estimated annual complications include 400,000 amputations³⁶ and approximately 100,000 deaths.^11,36

Snakes, while feared by many, are popular around the world as pets. The desire to keep venomous snakes as pets, which is typically illegal in the United States, and the implications throughout the world make the trade of exotic creatures second only to drugs and weapons on the international black market. In fact, the estimated annual worth of this trade in the United States alone is at least $15 million.¹³

This Special Consideration will discuss the evaluation and management of patients evenomated in the United States by non-native snakes (also known as exotic snakes). From 2007 through 2011, the American Association of Poison Control Centers’ (AAPCC) National Poison Data System (NPDS) recorded 622 nonnative (“exotic”) snakebites, with 250 of these thought to be from a venomous species (Chap. 136).

This same database was reviewed from 1995 through 2004 to characterize the types of exotic snakes involved and circumstances for the envenomations. During that time period, there were 399 exotic snakebites reported, of which 350 were identified by genus and species for a total of 77 different varieties.²⁸ One US expert reported 54 consultations regarding bites from nonnative venomous snakes.¹⁹

In the AAPCC data, the most common family responsible for envenonmations was the viperidae, making up 50% of these bites. Of the Viperidae, almost half of all bites were from four different species: Godman’s Pit Viper (Bothrops Godmanni), Gaboon viper (Bitis gabonica), Bush master (Lachesis mutus), and the Eyelash Viper (Bothrops schlegeli). The second most common family responsible for envenomations was the Elapidaes, resulting in 30% of US exotic snakebites. Sixty percent were from four different species: Indian Cobra (Naja naja naja), Monocellate Cobra (Naja naja kaouthia), Black Necked Spitting Cobra (Naja Nigricollis), and the King Cobra (Ophiophagus Hannah). The Indian Cobra was the most common snake identified during this study. Of note, there was one Atractaspidae bite (small scaled burrowing asp—Atractaspis microlepidota) and one Colubridae (Boomslang—Dispholidus typus).²⁸

TAXONOMY

The naming of snakes has evolved and the renaming currently continues at a rapid pace due to advances in DNA testing and ongoing research.^23,24,35 There are 2700 snake species in ...