Top Ten Exotic Snakebites in the USA
The non-native snake genera that most often cause US doctors to consider using antivenoms that lack FDA commercial licensure
Recently, I had occasion to draft a “Top Ten Exotic Snakebites” list, based on 17 years experience recorded by the American Association of Poison Control Centers. (Using the word “exotic” in this context means we are talking about bites by snakes that are not naturally found in the US, so the greater-than-4700 annual bites by native rattlesnakes, copperheads, cottonmouths and coral snakes don’t count.)
Fortunately, bites by exotic snakes are extremely rare. Unfortunately, so are repositories of exotic antivenom. We don’t have a funded, centralized program of antivenom distribution in this country, but we really should. It would be much safer – and overall less expensive – to prepare properly, together, than to beg and borrow antidotes under emergency circumstances and across thousands of miles. I figure that one step in the right direction is to consider how many medical cases we have.
To make this list, I re-analyzed the numbers that colleagues and I had published in two previous papers, which together covered the years 1995-2011. I grouped all species into genera. (For example, "Dendroaspis polylepis" and "Dendroaspis viridis" were grouped together simply as "Dendroaspis.") Then I rank-ordered all genera for which there were at least ten bites during the span of years studied.
Please note that about 10 additional snakebites per year are coded by poison centers as “exotic” without making the top-ten list. Also, some exotic snakebites are not reported to poison centers at all, so the numbers below are an underestimate of the actual number of exotic snakebites in the USA.
So here we go – the Top Ten Exotic Snakebite Genera in the USA, starting at #10:
#10. Atheris (bush vipers): 10 bites over 17 years, less than one per year.
#9. Vipera (Eurasian vipers): 13 bites over 17 years, also less than one per year.
#8. Trimeresurus (Asian lance-headed vipers): about one per year
#7. Crotalus (pit vipers, not US-native): slightly more than one per year
#6. Ophiophagus (king cobras): 25: 1-2 per year
#5. Dendroaspis (mambas): nearly 2 per year
#4. Lachesis (bushmasters): about 2 per year
#3. Bitis (African adders and vipers): about 3 per year
#2. Bothrops (American lance-headed vipers): nearly 6 per year
#1. Naja (cobras): 9-10 per year
Later I’ll come back to this list, in the context of which antivenoms are most and least available, and what we can do to improve the situation. Please subscribe to my blog, https://scorpiondoc.silvrback.com/, for future details.
For more details on exotic snakebites reported to American poison control centers, check out our two previously-published summaries:
Seifert SA, Oakes JA, Boyer LV. Toxic Exposure Surveillance System (TESS)-based characterization of US non-native venomous snake exposures. 1995-2004. Clin Tox. 2007;45(5): 571-578.
Warrick BJ, Boyer LV, Seifert SA. Non-native (exotic) snake envenomations in the U.S., 2005-2011. Toxins. 2014; 6(10):2899-2911.
Or, for overall snakebite numbers to compare with exotics:
Seifert SA, Boyer LV, Benson BE, Rogers JJ. AAPCC database characterization of native U.S. venomous snake exposures, 2001-2005. Clin Tox. 2009;47(4): 327-335.
I'm a medical toxinologist, writing to make my field less scary and more understandable to people everywhere.