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Idea of 'supervenom' is a myth, some experts say
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by tigers9 on June 14, 2008
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http://www.azcentral.com/arizonarepublic/local/articles/0614snakes0614.html
Is rattlesnake's bite growing deadlier?
Idea of 'supervenom' is a myth, some experts say
Kate Nolan
The Arizona Republic
Jun. 14, 2008 12:00 AM
It seems like the Arizona version of Snakes on a Plane, but it's not.
Doctors at Banner Poison Control Center in Phoenix alerted Valley emergency rooms in May to a spike in the number of "critically ill rattlesnake bite patients."
News reports ensued, heralding the prospect of a new rattlesnake supervenom and saying severe snakebites and deaths were zooming in California and Colorado as well as Arizona.
A San Diego doctor reported this week that he'd seen 20 severe snakebites since January and attributed them to the evolution of a more potent venom.
Hardware-store owners in Arizona were quick to advertise snake repellents and rattler tongs.
State wildlife and toxicology experts, however, remain skeptical of both the supposed rise in venom toxicity and the significance of the small increase in serious bites.
Government health agencies don't collect snakebite statistics, but bite experts agree that a small increase in serious bites may be occurring.
An estimated 400 people are bitten by rattlesnakes in Arizona every year, but fewer than 275 are treated. Relying on memory, experts said about five deaths have occurred in the state since 2002.
"A few bad cases can cause you to ask the right questions," said Jude McNally, a toxicologist who is managing director of the Arizona Poison Control Center in Tucson and who conducts research on venom.
McNally cites several reasons for rejecting the increased-toxicity notion. It would take eons for snakes to evolve a more potent venom, he said, especially across three states and several types of rattlesnakes credited with the superbites.
View of venom
Venom is complicated, containing 130 to 200 components that vary not only from snake to snake, but also within the same snake depending on age, season and myriad other factors, some unknown.
Citing results of a not-yet-published study, McNally said venom from one rattlesnake can be up to 10 times as toxic as that of another of the same type, depending on the location of the snake. Within that variability lies the fact that every baby rattler is born with enough venom to kill an adult human, McNally said.
"My strongest theory is that we are encountering different populations of snakes as we develop into the desert area and extend our geographical footprint," McNally said, echoing an increasingly common explanation for human-wildlife encounters with bad endings.
Two of the five people who died are known to have handled the snakes.
"An aggravated snake uses more venom," said Arizona Game and Fish biologist Thomas Jones.
The snake's survival instinct kicks in and it delivers a greater dose than it would use for prey, Jones said.
In some cases, the deaths involved Mojave rattlesnakes, known to have a highly toxic venom that can affect the central nervous system. Other rattlers have been found to have similar venom.
Dr. Steven Curry, the Banner poison center's medical director, isn't sure what to make of the small increase.
"We have no idea if it's a chance occurrence or not. All we did was send out a letter to ER physicians warning that we're seeing a lot more patients who are sick and near death when they get here, compared to previous years," Curry said.
The letter warned of symptoms - sudden collapse within minutes of the bite, plunging blood pressure, bleeding, shock and blocked airways - that could be mistaken for something else.
Increase since 2003
The poison center, which treats up to 75 snakebite patients a year, treated fewer than one serious bite a year in the past, but since 2003 has treated 15 patients with extreme symptoms from all over the state.
Statistically, the numbers don't add up to a trend.
Dr. Leslie Boyer of the Tucson poison center said physicians in the 36 hospitals she monitors routinely rate the severity of snakebites using six categories: death, major, moderate, minor, no effect and unknown. Since 2001, snakebite severity has not changed.
Those results include Cochise County, the area where the largest number of snake deaths occurred. That may be good news - particularly because Jones said he's never heard of a commercial snake repellent that works.
Reach the reporter at kate.nolan@arizonarepublic .com.
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RE: Idea of 'supervenom' is a myth, some experts s
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by Buzztail1 on June 14, 2008
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Two answers come immediately to mind.
Both involve "evolution" of a sort.
One is that snake venom probably does evolve in some small part continuously to adapt for prey animals "evolving" to become more resistant to venom.
Call it an accidental evolution. For instance, 47 pack rats get bitten by Mojave Rattlesnakes. 43 of those die and get eaten. 4 manage to survive, go on and breed, and raise agenerations of animals that are accidentally more resistant to Mojave Rattlesnake venom. And so on.
Two is that people are becoming less resistant to outside vectors. More and more people require "medicine" just to get through a normal day. We need Benadryl for allergies, Aspirin, Tylenol, Bufferin, Midol, etc for headaches and everyday aches and pains. Heck, they even advertise medicines on TV without telling you what the medicine is for! I think that people are becoming less capable of resisting the effects of venom, whether that is from continuous contact with polluted air, water, less nutritious food or whatever.
Just my own opinions,
Karl
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RE: Idea of 'supervenom' is a myth, some experts s
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by soberwolf on June 14, 2008
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Also we need to take into acount the number of bites increase as we further encroach on habitat. I for one bought a house last year in one of the new developments built on the outskirts of Phoenix in the beautiful desert. Of course being an amature herp' I dig the hell out of it. I have relocated a few snakes here mostly Bull snake and C.Atrox.Even a juvenile Banded Gila... Point being more encroachment means more bites..
One of the more rescent deaths in Az. (I love how the media reports only half the facts) A lady in Chino valley was killed by a Mohave. The media neglected to tell she was bitten several time while (get this) stabbing the snake with a screwdriver..Though venom is not intended for defense,, I'd say the snake was pretty pissed and scared. I'm sure the snake was more than happy to envenomate...
Another point as far as venom evolving.. It might make sense that as we encroach, natural prey becomes more and more scarce.. So naturally Mother nature takes over. To ensure survival, the venom could possibly become more potent. I'm by no means an expert in any of these topics. But, I do believe nature protects itself as best as it can.
Shelby
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RE: Idea of 'supervenom' is a myth, some experts s
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by Cro on June 14, 2008
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It is unfortunate, that although "statistically, the numbers don't add up to a trend," that the news papers are all over this story, publishing article after article about how the venom of these snakes is supposed to be getting stronger.
And it also is unfortunate, that scientists, medical doctors, and poision control folks, who should know better, are also quoting those "debatable" statistics, every time some reporter sticks a microphone in their face.
Disjunct populations of rattlesnakes that have evolved much stronger venoms makes a whole lot more sense than the whole population of a snake evolving a stronger venom.
This has been known for years among Herpetologists. The Canebrake Rattlesnakes in some parts of their range have a wicked mix of venom, that is far more toxic than the same snake over other parts of its range. Same thing is probably happening in the Mojave Rattlesnakes and Southern Pacific Rattlesnakes.
Another factor, it the difficulty that CroFab has in neutralizing snake bites. Any doctor who stops the dosage at the FDA reccomended maximum dosage, is likely to kill their patient if they are dealing with a severe bite. The old Wyeth polyvalent crotalid antivenin, despite being horse serum based, was much better at treating snake bites.
Under-treatment with CroFab could also cause doctors to think that the venom of snakes is stronger, while the real problem could be that the CroFab is weaker, and just does not work all that well on some bites, and requires large doses, and often needs to be dosed over several days.
As far as people being more suceptiable to the effects of a venomous snake bite, due to being less resistant to outside vectors, that is difficult to say. Those folks who live in cities, and eat processed foods, and breathe polluted air, definetly have more potential for lower resistance to toxins than those who have a healthy life style. However, are those the folks who are getting the more severe venomous snake bites ?
One would think that the folks getting the most snake bites would be the folks who live out in the boonies on farms and ranches, or, would be those who venture to the wilds for recreation. Both of those types of people are likely to be more hardy, and more healthy than their city dwelling friends.
The main thing we need to be carefull about these days, is "beliveing" something, just because it was printed in a news paper. Even, if they found some doctor who was willing the quote the statiistics. Did that Doctor do the research ? Or, did that Doctor even read the research ? Not likely. He probably was just the shortest drive from the news room for the reporter.
Anything printed in the media these days should be taken with not just a grain of salt, but a whole shaker full............
Best Regards John Z
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RE: Idea of 'supervenom' is a myth, some experts s
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by JoeCrotalid on June 14, 2008
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Larry:
Did you you read the article? It was Jude McNally of Arizona Poison Control and Leslie Boyer, a physician who treats snakebites who refuted the Sna Diego Doctor's claims. And no that doctor did not perform any research prior to may the out-landish claims to the news of a "super venom."
Don't knock the poison control centers and those physicians who dou know what the hell they are doing!
Case in point, I had a recent case in Florida in which we recommended against the surgeon performing a fasciotomy on a snakebite. The surgeon performed the snakebite despite our recommendation without any clinical indications-no s/s and no compartment measurements. The surgeon stated he can just look at the snakebite and know if they have compartment syndrome because he served in Iraq as a trauma surgeon performing fasciotomies on military personel with snakebites while serving in the dersert. As I have stated before-there are always arogant physicians who think they know everything about managing snakebites and refuse to consult those of us that do have experience in treating bites. Unfortunately-those are the physicians that usually get interviewed by the news without the facts. Don't lump us in the same boat as those morons.
Both myself and Chris have been recognized by Jude as experts in snakebites, and I have a great deal of respect for him and his knowledge of snakebites, and I know Leslie as well who is also quite experienced in envenomations.
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RE: Idea of 'supervenom' is a myth, some experts s
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by FLherp on June 15, 2008
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How many snakebites did he see in Iraq?
The tendency is to take notice of the unusual, so the any unusual bites are added together to create a trend where none may exist. The information on 'supervenom' is anecdotal at best. It may be a flawed deduction based on partial information. There is no mention of the number of dry, minor or moderate envenomations, there may have been an increase there as well. It may be a confluence of events that gives this appearance, perhaps local weather conditions, prey availability, encroachment on habitat, etc. all play a factor. We have a tendency to look for simple answers that explain everything, when there is a fundamental interconnectedness of things and sometimes the multiple causes are inextricable. In this case the severity of the bites is attributed to supervenom, is it based on evidence and can it be tested. The current evidence has been selected from a fairly small sample, broaden the sample and the trend may disappear.
Finding good statistics on snakebites is near impossible.
All evolution is 'accidental', it has no direction. Viewed retrospectively, it may appear to have direction - simple to complex, but that may be an artifact produced by viewing evolution from our perspective.
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RE: Idea of 'supervenom' is a myth, some experts s
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by nightwolf on June 15, 2008
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One possible reason for the jump in snake bites here in Arizona would be a housing / development boom here .
I've been told there are a lot of buzzers in this area , but Haven't had much time lately to go looking for them . But I know a LOT of scrub and ranch land has been turned into housing developments in a fairly short time .
Kenny
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