TABLE OF CONTENTS of this chain:
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11/ Snakebite < this panel > 12/ Netiquette 13/ Questions on conditions and travel 14/ Dedication to Aldo Leopold 15/ Leopold's lot. 16/ Morbid backcountry/memorial 17/ Information about bears 18/ Poison ivy, frequently ask, under question 19/ Lyme disease, frequently ask, under question 20/ "Telling questions" backcountry Turing test 21/ AMS 22/ Babies and Kids 23/ A bit of song (like camp songs) 24/ What is natural? 25/ A romantic notion of high-tech employment 26/ Other news groups of related interest, networking 27/ Films/cinema references 28/ References (written) 1/ DISCLAIMER 2/ Ethics 3/ Learning I 4/ learning II (lists, "Ten Essentials," Chouinard comments) 5/ Summary of past topics 6/ Non-wisdom: fire-arms topic circular discussion 7/ Phone / address lists 8/ Fletcher's Law of Inverse Appreciation / Rachel Carson / Foreman and Hayduke 9/ Water Filter wisdom 10/ Volunteer Work Panel 11 "There is in Melbourne a man who probably knows more about poisonous snakes than anyone else on earth. His name is Dr. Struan Sutherland, and he has devoted his entire life to a study of venom. "'And I'm bored with it,' he said when we went along to see him the next morning. 'Can't stand all these poisonous creatures, all these snakes and insects and fish and things. Stupid things biting everybody. And THEN people expecting me to tell them what to do about it. I'll tell them what to do. DON'T GET BITTEN IN THE FIRST PLACE. That's the answer." "Hydroponics, now, that's interesting...." --Douglas Adams, Chapter 2 "Here Be Chickens," in Last Chance to See See further for "What about a tourniquet?" Other relevant news groups: sci.bio.herp rec.pets.herp sci.med misc.emerg-services A glossary of technical terms can be found at the end of this FAQ. In Spanish: http://www.montanismo.org.mx/articulos.php?id_sec=11&id_art=385&id_ejemplar=99 TABLE OF CONTENTS [These lines may not correspond in your news reader.] Summary . . . . . . . . . . . . . . . . . . Line 121 Acknowledgments . . . . . . . . . . . . . . Line 174 References . . . . . . . . . . . . . . . . Line 191 Introduction . . . . . . . . . . . . . . . .Line 257 Various Snakes and their Effects . . . . . Line 321 Venoms . . . . . . . . . . . . . . . . . . Line 367 Five Special Cases . . . . . . . . . . . . Line 402 Nonvenomous Snakes . . . . . . . . . . . . Line 491 Identification . . . . . . . . . . . . . . Line 514 Coral Snakes . . . . . . . . . . . . . . . Line 525 Pit Vipers. . . . . . . . . . . . . . . . .Line 582 Copperhead . . . . . . . . . . . . . . . Line 628 Cottonmouth. . . . . . . . . . . . . . . Line 652 Speckled rattlesnake . . . . . . . . . . Line 679 The Three Nasties . . . . . . . . . . . . Line 700 Eastern Diamondback . . . . . . . . . . Line 730 Western Diamondback . . . . . . . . . . Line 773 Mojave . . . . . . . . . . . . . . . . . Line 799 Epidemiology: The Risk of Snakebite . . . . Line 864 Prevention . . . . . . . . . . . . . . . . Line 932 Envenomation . . . . . . . . . . . . . . . .Line 1011 Signs and Symptoms. . . . . . . . . . . . . Line 1045 Field Treatment . . . . . . . . . . . . . . Line 1103 Field Treatment: Areas of Disagreement. . . Line 1267 Field Treatment: 'Therapies' to Avoid . . . Line 1363 Hospital Care . . . . . . . . . . . . . . . Line 1467 Complications . . . . . . . . . . . . . . . Line 1515 Glossary . . . . . . . . . . . . . . . . . Line 1541 Disclaimer . . . . . . . . . . . . . . . . Line 1641 SUMMARY Poisonous snakebite is a potentially serious accident. It can lead to severe pain or other problems, and in the rare instance even death. However in North America it is not nearly as dangerous as most believe. Snakes seldom bite humans and even when they do so, their bites are seldom fatal. There is no need to allow fear of snakes to ruin your enjoyment of the outdoors. Snakes will usually avoid you if you give them a chance. Try to be sure they know you are coming. Don't reach into places they might hide. Be careful turning over rock and boards in snake country. Leave snakes alone; there is no simple rule to identify which are poisonous. The same advice applies to dead snakes and detached heads - reflex bites are as dangerous as bites from live snakes. At least half of all bites are caused by foolish behavior: handling or taunting venomous snakes, or failing to move away from a venomous snake once it has been sighted. If someone is bitten: The following treatment protocol is provided by Jeff Isaac and Peter Goth in The Outward Bound Wilderness First Aid Handbook, Lyons and Burford, 1991. "Transport the patient as quickly as possible to antivenin (antidote). Although local discomfort may be severe, systemic signs and symptoms may be delayed for two to six hours following the bite. Walking your patient out is reasonably safe unless severe signs and symptoms occur. It is also significantly faster than trying a carry. Splint the affected part if possible. Expect swelling. Remove constricting items such as rings, bracelets, and clothing from the bitten extremity. Do not delay. Immediately following the bite of a snake thought to be poisonous, evacuation should be started. It can always be slowed down or canceled if it becomes obvious that envenomation did not occur, or the snake is not poisonous. Most medical experts agree that traditional field treatments such as tourniquets, pressure dressing, ice packs, and "cut and suck" snakebite kits are generally ineffective and are possibly dangerous. Poisonous snakebite is one of those conditions that you cannot treat in the field. Don't waste valuable time trying." If it is going to be more than one hour to transport, you should consider rinsing and disinfecting the wound. [End of Summary] ACKNOWLEDGEMENTS At the outset we would like to thank the following for their helpful comments and suggestions: K.V. Kardong at the Dept. of Zoology, Washington State University Keith Conover, M.D., Dept. of Emergency Medicine, University of Pittsburgh loosemore-sandra@CS.YALE.EDU (Sandra Loosemore) firstname.lastname@example.org email@example.com (Paul Hollander) KLEINSCHMIDT@MCCLB0.MED.NYU.EDU (Jochen) CWA@NAUVAX.UCC.NAU.EDU (Curt Anderson) firstname.lastname@example.org.COM (Edward Reid) Paul Moler, a professional herpetologist with the Florida Dept. of Game and Freshwater Fish. REFERENCES This posting only scratches the surface. The following sources will provide more information: _The Outward Bound Wilderness First-Aid Handbook_ Jeff Isaac, P.A.-C. and Peter Goth, M.D. Lyons and Burford, 1991. Perhaps the best first aid book around at this time. _Medicine for Mountaineering_, (referred to as 'MFM' throughout this article) Third Edition 1985. James A. Wilkerson, M.D. ed. The snakebite section starts on p234. The section on treatment is now somewhat dated. _A Field Guide to Western Reptiles and Amphibians_, Robert C. Stebbins, Houghton Mifflin, 1966. A good guide to snakes and other reptiles including descriptions, color illustrations and maps of their ranges. Part of the Peterson Field Guide Series. Covers only the western U.S. _Rattlesnakes_, Laurence M. Klauber, University of California Press, 1982. This is a condensation of a 2 volume series on the same topic.This book does not provide as much identification information as does Stebbins, but it does include range maps. It provides a lot of interesting information about many topics ranging from the snake life cycle to collections of folklore and misinformation. Russell, Findlay E. 1980. _Snake venom poisoning in the United States_, Annual Review of Medicine, 1980, 31:247-59. Kurecki, Barnard A. and H. James Brownlee._Venomous snakebites in the United States_, The Journal of Family Practice, 1987, 25(4):386-92. Gold, Barry S. and Willis A. Wingert._Snake venom poisoning in the United States: A review of therapeutic practice_, Southern Medical Journal, June 1994, 87(6):579-89. Downey, Daniel J., George E. Omer, and Moheb S. Moneim._New Mexico rattlesnake bites: Demographic review and guidelines for treatment_, The Journal of Trauma, 1991, 31(10):1380-86. Curry, Steven C. et al., _The legitimacy of rattlesnake bites in central Arizona_, Annals of Emergency Medicine, 1989, 18(6):658-63. Iserson, Kenneth V._Incidence of snakebite in wilderness rescue_, Journal of the American Medical Association, Sept 9, 1988, 260(10): 1405. Antivenin (Crotalidae) Polyvalent under Wyeth-Ayerst Laboratories, in _Physicians Desk Reference_, Medical Economics Data: Montvale, NJ. 1995. Antivenin (Micrurus fulvius) under Wyeth-Ayerst Laboratories, in _Physicians Desk Reference_, Medical Economics Data: Montvale, NJ. 1995. Berkow, Robert (ed)._The Merck Manual of Diagnosis and Therapy. 14th Ed._, Merck, Sharpe and Dohme: Rahway, NJ, 1982. J.L. Behler and F. Wayne King. _The Audubon Society Field Guide to North American Reptiles and Amphibians_. Alfred A. Knopf: New York, 1979. _Conant, R. 1975. A field Guide to Reptiles and Amphibians of Eastern and Central North America_, Houghton Mifflin Company;Boston. Covers the eastern U.S. but there is also a Western edition by Stebbins (see above). Minton, Sherman A. Poisonous Snakes and Snakebite in the U.S.: A Brief Review. Northwest Science, 61(2): 130-37, 1987. INTRODUCTION Snakebite is always a hot topic. In what follows we will attempt to describe prevention and treatment of bites by poisonous snakes in North America as well as the effects of such bites. Be aware that we are dealing with overreaction and hype here. Popular literature, folklore, and movies have greatly exaggerated both the probability of snakebite and the likely outcome should it happen. Humans are much less likely to get bitten than many people believe. Furthermore snakebite, while serious, is not the death sentence often implied. Snakes, poisonous and otherwise, have excited a lot of aversion and superstition over the ages, resulting in unwarranted fear and sometimes even panic. This fear and panic can lead to: Improper treatment of those cases which need treatment for envenomation. Dangerous overtreatment for bites in which envenomation does not occur. Worsening the outcome of snakebites due to panic. Unnecessary and dangerous treatment of bites by nonvenomous snakes. Unnecessary, expensive, and dangerous rescue operations. Unnecessary destruction of snakes and their habitat. Snakebite in the U.S. should be treated conservatively. There is no need to jump in with knives, tourniquets, ice, or compression bandages. There is no need to try to suck out the venom by mouth. Carrying out any of these extreme procedures has the potential to do far more harm than good. We will explain later in this FAQ the reasons that such extreme measures do not form part of the therapy for snakebite. Victims should be given only the appropriate treatment and then be rapidly evacuated to medical facilities. Wilkinson in Medicine for Mountaineering has this to say, "About no other medical subject has so much been written when so little has been known!" "Poisonous snakebites are unquestionably serious, potentially deadly accidents. Nonetheless, the danger from a single bite has been greatly exaggerated, particularly in the United States, where an average of less than fifteen people die each year as the result of bites by poisonous snakes. Less than one percent of poisonous snakebites in this country are lethal. In other parts of the world poisonous snakes are a more serious problem. Many of the snakes in those areas have a much more toxic venom, treatment is less successful, and sophisticated medical care is less available." (MFM p234) Of course severity will vary with species as well as with the individual snake. Larger snakes of the same species tend to have more venom (although the larger snake may have learned to ration its venom while a younger animal may be more likely to inject the full load). In North America we do not have the really nasty varieties of snakes found in some parts of the world. There is no reason to panic when someone is bitten by a snake. Even the "three nasties" described below are not nearly as dangerous as the cobras, black mambas and death adders found outside the U.S. VARIOUS SNAKES AND THEIR EFFECTS: Venomous snakes in the U.S. all belong to one of two families: Crotalids (pit vipers): copperhead cottonmouth or water moccasin the numerous species of rattlesnakes Elapids coral snake (eastern and Arizona species) Crotalids have the most efficient injection mechanism of any snake. They are equipped with long hollow fangs and a system to inject venom through those fangs. They have the ability to inject large volumes of venom quickly. Crotalid fangs can fold back into the mouth; lack of visible fangs does not necessarily mean an unarmed snake. Most crotalids have venom that is less toxic than that of coral snakes. Crotalids, however, are the more dangerous group because (a) they are more likely to bite a human, (b) they can inject venom much more efficiently, and (c) they are usually larger and have more venom to use. Elapids on the other hand have grooved fangs. This is a much less efficient injection mechanism. They chew to get the venom into the victim. The size of coral snakes limits them to biting fingers or loose folds of skin. The elapidae include some of the world's nastiest critters: the black mamba, the death adder, and the cobra. The two species of coral snakes in North America are about as mild as poisonous snakes can be. They are not aggressive. Children have reportedly played with coral snakes for hours without being bitten, but no record exists of how many parental heart attacks this has caused! The venom is potent, however, and treatment should be given for bites which do occur. Coral snake bites make up less than 2% of all U.S. snakebites. In fact, Gold and Wingert report that fewer than 25 of all reported venomous snakebites per year are from coral snakes. There have been no known fatalities from coral snake bites since the development of the _Micrurus fulvius_ antivenin (Wyeth-Ayerst Laboratories). The Arizona coral snake (Micruroides euryxsanthus) is less dangerous than the eastern coral snake (Micrurus fulvius). It is smaller and would have a hard time biting a person even if inclined to do so. The rare bites which do occur should be treated the same as bites from the eastern coral snake. VENOMS: Snake venom usually contains two types of poison: hemolytic toxins which attack the walls of blood vessels and neurotoxins which attack the nerves. Hemolytic toxin attacks blood vessel walls, allows serum to escape into the surrounding tissues, and causes clotting within the vessels. The result is severe swelling, pain, and discoloration at the site of the bite. In the few cases where hemolytic toxins cause death, the actual cause is likely to be shock. The effects of hemolytic toxin are immediate and primarily localized. Symptoms will be obvious. Neurotoxins produce much less obvious immediate symptoms, at times fooling the victim into believing envenomation has not occurred. But systemic symptoms can appear later. Neurotoxins produce much less local reaction than do hemolytic toxins. On the other hand, they can affect nerves quite removed from the site of the bite. In extreme cases they can cause respiratory arrest, although this is uncommon with the bites from most North American snakes. However, respiratory distress without actual arrest may to occur in neurotoxin victims. Less severe symptoms from neurotoxins include tingling or prickly feelings and eyelid paralysis. All snake venom probably has some of each kind of toxin. But, most pit vipers have a higher fraction of hemolytic toxin, and elapids have more neurotoxin. The Mojave rattlesnake, a pit viper, is an exception; see below. The potency of venom will vary, with species, with time of year and with geographic area. The typical snake mouth is no cleaner than a human's. So, they tend to induce microbial contamination into bites. Although it is common for a snake to bite without injecting venom, microbial contaminants will always be present and should always be treated. Such contamination seems to be much less of a problem in bites by nonvenomous snakes, perhaps because their bites do not penetrate so deeply. FIVE SPECIAL CASES: FIVE varieties deserve special mention: A single bite from a copperhead is not very dangerous. The diamondbacks (eastern and western species) and the Mojave rattlesnakes deserve attention because they are particularly dangerous. The speckled rattlesnake should also be mentioned because bites from it, like those from the Mojave, may not produce local pain or other reaction. (It is worth noting, however, that Findlay Russell points out that pain is not always associated with an envenomated bite from any variety of snake). The copperhead has probably the mildest venom of any poisonous snake in the U.S. Adults bitten by a single copperhead usually need only supportive therapy and good cleansing and disinfection of the wound. A study of 400 victims of copperhead bites found only 2 deaths, both the result of simultaneous bites by 3 or more snakes. About 3,000 bites a year are inflicted by copperheads. You would probably want treat a copperhead bite pretty much as any other pit viper bite, but would be able to reassure the patient a bit more and would not be as concerned if medical help were not readily available. This not to say that a copperhead bite won't hurt, it will. These bites are still serious but are unlikely to be life threatening. Gold and Wingert state that "It [antivenin] is unnecessary in most cases of copperhead bite and pygmy rattlesnake bites. The diamondbacks, on the other hand, are potentially deadly. Both the eastern and western versions are huge, the western species compensating for its slightly smaller size with a more potent venom. MFM lists the eastern diamondback as an aggressive snake and claims it is responsible for more human deaths than any other U.S. snake. Others dispute this. Paul Moler argues it is not particularly aggressive and quotes some numbers which indicate that it is unlikely to lead in killing people. The Mojave rattler is dangerous in spite of its size. This little rascal is armed with a very potent venom, high in neurotoxins. Pain and other local responses to the bite may be mild, but the systemic response may be marked. Initial reaction is usually mild with severe symptoms coming 12 to 16 hours after the bite. The early symptoms could easily fool one into believing there was no problem. By the time severe symptoms appeared the best time for treatment would have passed. The Mojave rattlesnake also has a couple of close relatives south of the border, the Mexican west coast rattler and the South American tropical rattlesnake, also known as cascabel or neotropical rattlesnake. They provide problems at least equal to those of the Mojave version. It is worth mentioning that bites from other North American venomous snakes may yield little local pain, swelling, or other reaction following envenomation. This true of bites from the speckled rattlesnake,_Crotalus mitchelli_, and possibly also of bites from the rock rattlesnake, _Crotalus lepidus_, and tiger rattlesnake, _Crotalus tigris_ (Minton, 1987). If you know that you have been bitten by one of these snakes, it is probably best to assume that you have been envenomated and procede to a hospital. Envenomated bites from either the diamondback or the Mojave rattler are serious, possibly even deadly. Do your level best to evacuate the victim quickly to medical facilities. There is of course a wide variety of poisonous snakes throughout the world. We can't discuss them all here. They are generally confined to warmer climates in places such as Australia, Africa, the Indian subcontinent, and Southeast Asia. Many of these snakes much more dangerous than those native to the North America. There are some exceptions with more northerly ranges. For example, the habitat of the European viper extends to the Arctic Circle. It is not, however, as dangerous as some of the snakes inhabiting warmer climates. If you plan to engage in wilderness activities overseas you should research their venomous snakes. MFM does have some information on other areas as well as a list of central medical facilities which can provide more information. If you are not familiar with the snakes in an area, assume they are dangerous (especially in warm climates). If you are bitten by an exotic snake in the U.S. (a pet, a zoo specimen, or a research specimen) your physician will want to contact a referral center for information on treatment and antivenin availability. There are numerous relevant entries in a list at URL <http://www.desertusa.com/mag98/mar/stories/rattlein2.html>, including one for the referenced center: ARIZONA POISON & DRUG INFORMATION CENTER Arizona Health Sciences Center, Room #1156 1501 North Campbell Avenue Tucson, AZ 85724 Emergency Phone: (800) 362-0101 (AZ only) (520) 626-6016 Administrative Phone: (520) 626-7899 FAX: (520) 626-2720 E-MAIL: email@example.com Website: http://www.Pharmacy.Arizona.EDU/centers/poisoncenter/apdicindex.html (Note that the 1-800 number is limited to in-state calls only.) the Oklahoma City Zoo (405-424-3344), the Rocky Mountain Poison Center (303-629-1123), or the New York City Snakebite Emergency Center (718-430-6494). If your physician desires more information on the two antivenins used for the treatment of North American snakebites, he can contact the manufacturer: Professional Service Wyeth-Ayerst Laboratories PO Box 8299 Philadelphia, PA 19101 (610) 688-4400, or (800) 950-5099 NONVENOMOUS SNAKES Snakes regarded as nonvenomous are not necessarily completely safe. The saliva of many of these snakes can contain the same toxins as the venom of their more feared relatives. Some snakes such as the gopher snake lack anything resembling venom, and others such as the hognose and garter snakes have saliva which could be considered a mild venom. After all, true snake venom is just modified saliva anyway. These so-called nonvenomous snakes lack an efficient means of delivering their saliva/venom to a human victim. Yet there are recorded cases of them envenomating and even killing people. The victims tend to be people who regularly handle snakes either professionally or as a hobby. The most common reaction to such a bite (at least in the U.S.) is the swelling, pain, and discoloration caused by hemolytic toxins. But neurotoxins have also been identified in the saliva of some of these snakes. More information on this subject can be found in several references. One we were able to locate was, Sherman A. Minton, Jr. "Beware: Nonpoisonous Snakes," _Natural History_, 87: 56, Nov 1978. IDENTIFICATION: Rule One: Leave snakes alone. There is no reliable rule to distinguish which snakes are venomous and which are not. Characteristics vary greatly depending on locale and occasional individuals have atypical coloration or pattern. Rule One, Expanded: Unless you are engaged in legitimate biological research, leave undisturbed all wildlife you encounter in the wilderness. Coral Snakes It is useful to be able to identify the dangerous species of snakes. However it is not always easy. Coral snakes are probably the easiest to properly identify, they are small (usually no more than about 30 inches long, sometimes up to 40 inches), thin, brightly colored, and have small heads. They can be distinguished from the nonvenomous king snake and other harmless mimics by the presence of adjacent red and yellow bands. Milk snakes, king snakes, and the other mimics have adjacent red and black bands: Red touch yellow - kill a fellow Red touch black - venom lack. Another mnemonic is to think of a traffic light. If red is adjacent to yellow, stop! There are two species, the Arizona coral snake (Micruroides euryxanthus) and the eastern coral snake (Micrurus fulvius). Bebler and King describe the Arizona coral snake (Micruroides euryxanthus) as follows: "Description: 13-21 inches. Blunt-snouted and glossy, with alternating wide red, wide black, and narrow yellow or white rings encircling the body. Head uniformly black to angle of jaw. Scales smooth, in 15 rows. Anal plate divided. Habitat: Rocky areas, plains to lower mountain slopes; rocky upland desert especially in arroyos and river bottoms; sea level to 5900 feet. Range: C. Arizona to sw New Mexico south to Sinaloa, Mexico. This snake emerges from a subterranean retreat at night, usually during or following a warm shower. When disturbed by a predator, it buries its head in its coils, raises and exposes the underside of its tail, and may evert its cloacal lining with a popping sound. Eats blind snakes, other small snakes." Bebler and King describe the eastern coral snake (Micruroides fulvius) as follows: "Description: 22-47 inches. Body encircled by wide red adn black rings separated by narrow yellow rings. Head uniformly black from tip of blunt snout to just behind eyes. Red rings usually spotted with black. Scales smooth and shiny in 15 rows. Anal plate divided. Habitat: Moist, densely vegetated hammocks near ponds or streams in hardwood forests; pine flatwoods; rocky hillsides and canyons. Range: Se. North Carolina to s. Florida and Key Largo, west to s. Texas and Mexico. Usually seen under rotting logs or leaves or moving on surface in early morning or late afternoon. Feeds on small snakes or lizards." Pit Vipers Pit vipers are a bit more difficult. Of course the presence of rattles tells you that you are dealing with a venomous snake, but absence thereof gives no assurance to the contrary. Copperheads and cottonmouths have no rattles, and even rattlers sometimes loose their rattles. The presence of fangs indicates a venomous snake, but these may be folded back in the mouth and difficult to detect. The fangs may even be broken off. The easiest indicator (but one which requires practice, maybe in a zoo) is the characteristic heavy body and triangular head of the pit viper. Although some nonvenomous snakes also have these characteristics it is always best to treat a snake with caution. In a dead snake you could look for the pit after which the pit viper is named. This will be between the eye and nostril, one on either side of the head. Another sure indicator is the scales behind the anal plate. Pit vipers have a row of single scales reaching across the underside of their bodies behind the anus while most other snakes have a double row of scales, joining in about the middle. Some references suggest checking the pupils of the snake's eyes for identification. Pit vipers will have vertical slit pupils. If the snake has round pupils it is not a pit viper. These fine characteristics are probably only useful in identifying a dead snake. One wouldn't want to pick up a live one to look at its underscales or its pupils. One good indicator of the type of snake is the location. Snakes don't wander far from home. They tend to have a limited range and will not survive outside the conditions they prefer. Except in the case of an exotic pet you will not find them in areas far removed from their normal range. You simply won't find a Mojave rattler in Ohio or an eastern diamondback in Colorado. Several of the books listed above describe the ranges for various species, usually with maps. Body markings are rarely sufficient for identification by the inexperienced. It takes a lot of practice to learn to distinguish between various species, some of which are quite similar externally. Furthermore, individuals of the same species can have varying shades of color, making such identification even more difficult. See the references listed above for pictures and other help in identification. If you are concerned about venomous snakes, get a book on herpetology and study it. Visit zoos and talk with specialists. You will not become an expert by reading usenet. Again, the best rule is, leave snakes alone! Getting close enough to identify pits or scales is dangerous. You might then be able to also examine the fang marks on your body! Copperhead Bebler and King describe the copperhead (Agkistrodon contortrix) as follows: "Description: 22-52 inches. Stout-bodied; copper, orange, or pink-tinged, with bold chestnut or reddish-brown crossbands constricted on midline of back. Top of head unmarked. Facial pit between eye and nostril. Scales weakly keeled, in 23-25 rows. Anal plate single. Habitat: Wooded hillsides with rock outcrops above streams or ponds; edges of swamps and periodically flooded areas in coastal plain; near canyon springs and dense cane stands along the Rio Grande; sea level to 5000 feet. Range: Sw. Massachsetts west to extreme se. Nebraska south to Florida panhandle and sc. and west to Texas. It basks during the day in spring and fall, becoming nocturnal as the days grow warmer. Favored summer retreats are stonewalls, piles of debris near abandoned farms, sawdust heaps, and rotting logs, and large flat stones near streams.... In fall, copperheads return to their den site, often a rock outcrop on a hillside with a southern or eastern exposure." Cottonmouth Bebler and King describe the cottonmouth or water moccasin (Agkistrodon piscivorus) as follows: "Description: 20-74 inches. A dark, heavy-bodied water snake; broad-based head is noticeably wider than neck. Olive, brown or black above; patternless or with serrated-edged dark crossbands. Wide light-bordered, dark brown cheek stripe distinct, obscure, or absent. Head flat-topped; eyes with vertical pupils (not visible from directly above as are eyes of harmless water snakes); facial pit between eye and nostril. Young strongly patterned and bear bright yellow tipped tails. Scales keeled, in 25 rows. Habitat: Lowland swamps, lakes, rivers, bayheads, sloughs, irrigation ditches, canals, rice fields, to small clear rocky mountain streams; sea level to ca. 1500 feet. Range: Se. Virginia south to upper Florida Keys, west to s. Illinois, s. Missouri, sc. Oklahoma and c. Texas. Isolated population in nc. Missouri. When annoyed, the cottonmouth tends to stand its ground and may gape repeatedly at an intruder, exposing the light cotton lining of its mouth. Also called trap jaw or water moccasin. Unlike other water snakes, it swims with head well out of water. Although it may be observed basking during the day, it is more active at night. Preys on sirens, frogs, fishes, snakes, and birds." Speckled Rattlesnake Bebler and King describe the speckled rattlesnake (Crotalus mitchelli) as follows: "23-52 inches. Pattern and color vary greatly; generally has a sandy, speckled appearance. Back marked with muted crossbands or hexagonal to diamond shaped blotches formed by small clusters of dots. Large scale above eye ptted, creased, or rough-edged; or rostral scale separated from preanals by row of tiny scales. Scales keeled, in 23-27 rows. Habitat: Prefers rugged, rocky terrain, rock outcrops, deep canyons, talus, chaparral amid rock piles and boulders, rocky foothills; sea level to 8000 feet. Range: Extreme sw. Utah, s. Nevada and s. California south into nw. Sonora and throughout Baja California. Active during the day in spring and fall, at night in summer. Eats ground squirrels, kangaroo rats, white-footed mice, birds, and lizards." The Three Nasties There are three species worth extra attention if you frequent their ranges. These all have the venom to make you pay dearly should you upset them. Different sources give different assessments of the dispositions of the eastern diamondback and the Mojave rattler. Some list them as short tempered and quick to strike humans, while others say that they are not very aggressive. There is, however, general agreement that both of these plus the western diamondback pack a nasty wallop if they do bite. It is useful to know if you are in their range and be able to recognize them in order to get proper treatment should someone get bitten. While a major distinguishing feature of both diamondbacks (at least in the adult snake) is their size, this may be an unreliable indicator. Even experts have a difficult time estimating the size of a live snake, a problem compounded when a novice unexpectedly encounters one. Size estimates are typically quite generous to say the least. If the snake is dead and can be measured you can get useful information. Most of the danger of a diamondback comes from its size and the quantity of venom anyway. It won't make much difference if it is a juvenile diamondback or an adult of some other species (except the Mojave). Various authors do not agree on which is the most dangerous. Some claim this honor for the eastern diamondback, and some for the western version. The eastern species is larger and has more venom but its western cousin has a more potent venom. The Mojave rattlesnake is also a good candidate for the most dangerous snake in the U.S Its very potent venom with the delayed action make it a real danger. Not that it matters much, one would not want to be bitten by any of the three. Eastern Diamondback (Crotalus adamanteus) According to Conant's Reptiles & Amphibians of Eastern/Central U.S. , "33-72 inches; record 96 inches [Bebler and King give the range as 36 to 96 inches]. An ominously impressive snake to meet in the field. The diamonds, dark brown or black in color, are strongly outlined by a row of cream-colored or yellowish scales. Ground color olive, brown, or almost black. Pattern and colors vivid in freshly shed specimens; dull and quite dark in those preparing to shed. Only rattler within its range with 2 prominent light lines on face and vertical light lines on snout. At home in the palmetto flatwoods and dry pinelands of the South. Occasionally ventures into salt water, swimming to outlying Keys off the Florida coast. Some snakes will permit close approach without making a sound, whereas others, completely concealed in palmettos or other vegetation, will rattle when dogs or persons are 20 or 30 feet away. Many stand their ground, but when hard pressed they back away, rattling vigorously but still facing the intruder. Frequently they take refuge in burrows of gopher tortoises, in holes beneath stumps, etc. Rabbits, rodents, and birds are eaten. Range: Coastal lowlands from se. N. Carolina to extr. E. Louisiana; all of Florida, including the Keys." According to Behler and King's Audubon herpetology guide: "Our largest rattler. Heavy-bodied with large head sharply distinct from neck. Back patterned with dark diamonds with light centers and prominently bordered by a row of cream to yellow scales. Prominent light diagonal lines on side of head. Vertical light lines on snout. Scales keeled, in 27-29 rows." Range and habitat same as above, but get this, "Give it a wide berth; most dangerous snake in North America! Venom highly destructive to blood tissue. Stumpholes, gopher tortoise burrows, and dense patches of saw palmetto often serve as retreats. Their numbers have been substantially reduced by extensive land development and by rattlesnake hunters. Eats rabbits, squirrels, birds" The following descriptions of the Mojave and western diamondback are taken from Stebbins's book: Western Diamondback Rattlesnake (Crotalus atrox) "Identification: 30-89 inches. The largest western rattlesnake. Above: gray, brown or pink with brown diamond or hexagonal blotches on the back and fainter smaller blotches on the sides. Markings often indefinite and peppered with small dark spots, giving an overall speckled or dusty appearance. Tail set off from the rest of the body by broad black and white rings, about equal in width; hence sometimes called the "coontail" rattler. A light diagonal stripe behind the eye intersects the upper lip well in front of the corner of the mouth. Young: 9-14 inches, markings more distinct than in adult. Frequents a variety of habitats in arid and semiarid regions from the plains into the mountains - desert, grassland, brushland, woodland, rank growth of river bottoms, rocky canyons, and lower mountain slopes. Crepuscular and nocturnal, but also abroad in daytime. Perhaps the most dangerous North American serpent, often holding ground and boldly defending itself when disturbed. Live-bearing. Range: SE California to E Oklahoma and E Texas, south to Isthmus of Tehauantepec. Old records for central Arkansas and Trinidad, Las Animas Co., Colorado. Sea level to 7000 feet." Mojave Rattlesnake (Crotalus scutulatus) "Identification: 24-51 inches. Well-defined, light-edged dark gray to brown diamonds, ovals, hexagons down middle of back; light scales of pattern usually entirely light-colored. Ground color greenish gray, olive green, brownish, or yellowish. A white to yellowish stripe extends from behind the eye to a point behind the corner of the mouth except at extreme southern end of range. Tail with contrasting light and dark rings; dark rings narrower than light rings. Enlarged scales on snout and between the supraoculars. Chiefly inhabits upland desert and lower mountain slopes, but ranges to about sea level near the mouth of the Colorado river and to high elevations in the Sierra Madre Occidental. Habitats vary--barren desert, grassland, open juniper woodland, and scrubland. This rattler seems to be most common in areas of scattered scrubby growth such as creosote bush and mesquite. Not common in broken rocky terrain or where vegetation is dense. Eats kangaroo rats and other rodents; and probably other reptiles. AN EXTREMELY DANGEROUS SNAKE; EXCITABLE AND WITH HIGHLY POTENT VENOM. Range--S. Nevada to Puebla, near southern edge of Mexican Plateau; western edge of Mojave Desert, Calif. to extreme w. Tex. From near sea level to around 8300 feet." In case of a bite it may be important to distinguish between the diamondback and the Mojave. The ranges of the species overlap and if you are in the area of overlap you may not know which was the culprit. The distinction is important in the case of a bite with little or no local reaction. In a diamondback bite, lack of reaction within 4 to 6 hours indicates that envenomation did not occur. However if a Mojave was the culprit no such assumption can be made and systemic reaction may occur 12-16 hours later. The two species are very similar in appearance. The relative width of light and dark tail bands may be the best way to distinguish between the two. If uncertain, assume the snake was a Mojave and treat accordingly. Other similar snakes include the speckled and western rattlesnakes (there are several sub-species of the speckled). Their ranges also overlap those of the Mojave and diamondback. Mojave venom can be up to 20 times the as potent as diamondback venom, although its quantity will typically be about 1/6 that of a diamondback. Specific references to Mojave and its unusual venom are: _The Venomous Reptiles of Arizona_, (Arizona Game and Fish) pp 55-56. _Journal of Herpetology_, Vol 23 no. 2, pp 131ff (1989) _Herpetologica_, vol 47 No. 1 (March 1992) pp 54ff One other note on the Mojave: There is a central Arizona version which can be considered a subspecies. The principal difference between it and its more widely distributed cousins is that its venom is very similar to diamondback venom. This therefore makes it less dangerous than other Mojaves. There are also hybrids which have components from both venom types. Hybrids present the particular danger of a local reaction which may fool victims and medical personnel into believing the culprit was a some other rattler until the systemic reaction due to neurotoxin sets in later. Even experts can't tell the difference between different varieties of Mojave except by analyzing the venom. There are a number of other species of rattlesnakes in North America. Information on their identification can by found in the Peterson or Audubon field guides. EPIDEMIOLOGY: THE RISK OF SNAKEBITE Your risk of being bitten be a snake is small, and so too is your risk of dying if bitten. Findlay E. Russell writes in Ann Rev Med 1980, 31:247-59., "Although there are an estimated 45,000 bites by all snakes in the United States each year, only about 6680 persons are treated for snake venom poisoning. However, it can be expected that at least 1000 additional bites by venomous snakes occur each year and that they are either not treated or go unreported. During the past five years, the number of deaths from snakebite in the United States has ranged between 9 and 14. Most of the deaths occurred in children, in the elderly, in untreated, mistreated, or undertreated cases, in cases complicated by other serious disease states, or in members of religious sects who handle serpents as part of their worship exercises and refuse medical treatment. Almost all reported deaths have been attributed to rattlesnakes." In a second article (When a snake strikes, Emergency Medicine, 1990, 22:21-43.), Russell states, "25% of all pit viper bites do not result in envenomation and another 15% are so trivial, they require only local cleansing and tetanus prophylaxis." Kurecki and Brownlee write in The Journal of Family Practice 1987 25(4):386-392, "Approximately 75 percent of all snakebites occur in people aged between 19 and 30 years, 1 percent to 2 percent occur in women, and less than 1 percent occur in blacks. Approximately 40 percent of all snakebites occur in people who are handling or playing with snakes, and 40 percent of all people bitten had a blood alcohol level of greater than 0.1 percent. Sixty-five percent of snakebites occur on the hand or fingers, 24 percent on the foot or ankle, and 11 percent elsewhere. One case was reported of a snakebite on the glans penis." So it seems that getting drunk and messing about snakes is a big cause of getting bitten. It also seems that male yahooism is a precursor to snake toxin poisoning. Women are unlikely to get themselves bitten, and if they do get bitten, it is unlikely that they got that way by doing something stupid. Here is some more interesting data on that point from Curry et al. in Annals of Emergency Medicine 1989 18(6):658-63: "We reviewed medical records of 85 consecutive snakebite victims cared for at a single medical center to determine legitimacy of snakebites. A bite was considered illegitimate if, before being bitten, the victim recognized an encounter with a snake but did not attempt to move away from the snake. A legitimate bite was said to have occurred if a person was bitten before an encounter with a snake was recognized or was bitten while attempting to move away from a snake. The study group was made up of 75 male (87.2%) and 11 female (12.8%) victims. Seventy-four percent were 18 to 50 years old, and 15% had been bitten previously. Only 43.4% of all bites were considered legitimate, and pet (captive) snakes accounted for almost one third of all illegitimate bites. The ingestion of alcoholic beverages was associated with 56.5% of illegitimate bites versus 16.7% of legitimate bites. While 74.4% of bites were to upper extremities, only 27% of upper extremity bites were legitimate. All bites to the lower extremities were legitimate. Of 14 individuals bitten by pet snakes, all were men and 64.3% were under the influence of alcohol at the time of the bite. In our patient population, the data suggest that a 16% reduction in rattlesnake bites would result if rattlesnakes were not kept as pets, and more than one half of all rattlesnake bites would be eliminated if persons simply would attempt to move away from a rattlesnake after an encounter is recognized". It is worth noting that only one woman in Curry et al.'s study group received an illegitimate bite. PREVENTION: Obviously the best prevention is to avoid getting bitten. It helps that humans are not the natural prey of any venomous snake. We are a bit large for them to swallow whole and they have no means of chopping us up into bite size pieces. Nearly all snakebites in humans are the result of a snake defending itself when it feels threatened. In general snakes are shy and will simply leave if you give them a chance. Remember, MOST BITES HAPPEN TO PEOPLE WHO FAIL TO MOVE AWAY FROM SNAKES ONCE THEY SEE THEM. So don't pick up, torment or otherwise mess about with venomous snakes. In light of the Curry data, avoiding alcohol or drug intoxication in snake country would be a good idea. Many, many bites are associated with intoxication. Another basic rule is to be sure the snake knows you are coming. Walk heavily; they may sense ground vibrations better than sound. If they sense your presence they will almost always leave before you even know they are there. (This may not apply in other parts of the world. Some of the more potent snakes may protect their territory as well as their bodies.) If you do unexpectedly confront a snake, stay calm, back away and do nothing to threaten it. (This assumes of course that the surprise didn't cause you to jump well beyond the snake's reach. It's amazing what the human body can do in such circumstances.) Don't run around barefoot in snake country, especially after dark. During warm weather snakes will be most active at night and will defend themselves if stepped on or if you walk too close and they sense danger. MFM lists going barefoot and gathering firewood after dark as two common activities leading to snakebite. Going barefoot not only exposes your feet, it also makes your footsteps quieter so you are less likely to be felt. You could invest in a pair of snakeproof boots but any high top leather boot is probably adequate. Long pants will also help since the snake has difficulty biting through a fold of your clothing. Remember that snakes like to hide under rocks, logs, and brush to protect themselves from sun or cold. Be very careful in snake country about moving such objects or reaching into anywhere a snake might hide. A snake might well perceive your actions as aggressive and defend itself. There may be more than one snake in the same place and, taken by surprise, they may strike without warning. Furthermore snakes will be more likely to bite your unprotected hand rather than a leg or foot protected by clothing. Remember, according to Curry, 74.4% of bites are to the upper extremities. Rock climbers should be careful in snake country. Snakes like to sun themselves on ledges and it can be a real eye-opener to poke your head up and stare one in the eyes. And while you won't find them in the middle of a 5.12 face you may find them in cracks and on ledges. Remember, the mice and rats which inhabit many cliff areas mean food to a snake and so attract them. Small rock outcrops scattered around on foothills are prime snake territory, so be particularly careful when you go bouldering. Be careful entering old buildings such as mining cabins. They make nice homes for snakes. Obviously you should not handle or tease poisonous snakes. Less obvious is the danger of handling them when they are dead. A reflex strike from a dead snake can be just as dangerous as a bite by a live one. This warning also applies to detached heads of dead snakes. The degree of protection afforded by responsible behavior and protective clothing (boots, long pants) is remarkable. Iserson in JAMA reported on the incidence of snakebite in three groups of experienced outdoor workers. Members of the Southern Arizona Rescue Association worked 115,000 person-hours in the field without a snakebite. The personnel at the La Selva Biological Station in Costa Rica (habitat of the fer de lance, a venomous crotalid) worked for 350,000 person-hours in the field without a bite. The graduate students at the Organization for Tropical Studies, also in Costa Rica, worked 660,000 person-hours in the field with only one bite. Russell has something to say about this as well, "Few bites occur in backpackers, serious hunters, or fishermen...In the past 20 years, there has been only one backpacker in the Sierras of California, who I know of, who was bitten by a rattlesnake, and this happened when he was changing a tire at the end of his hike." ENVENOMATION In the article -When a snake strikes- ( Emergency Medicine, 1990, 22:21-43.), Russell states, "25% of all pit viper bites do not result in envenomation and another 15% are so trivial, they require only local cleansing and tetanus prophylaxis." Kurecki and Brownlee report that, "Coral snakes lack retractable fangs. Instead they rely on fixed retroverted teeth to gnaw into the flesh of their prey. They must penetrate the skin long enough for their venom to be deposited around their teeth and into the wound. This envenomation mechanism is much less efficient than that of pit vipers; consequently, 50 percent of coral snakebites are dry." The severity of the reaction to a snakebite depends on the degree of envenomation. Downey, Omer and Moneim describe a system whereby, "grade 0 means there is no envenomation and indicates swelling and erythema [redness] around the fang marks of <2.5 cm, grade 1 indicates swelling and erythema of 2.5 to 15 cm but no systemic signs, grade 2 indicates swelling and erythema of 15 to 40 cm with mild systemic signs, grade 3 indicates swelling and erythema of >40 cm with systemic signs, and grade 4 indicates severe systemic signs including coma and shock." In their series of 36 patients, there were no grade 0 bites, five grade 1 bites, 27 grade 2 bites, three grade 3 bites, and no grade 4 bites. So, this study suggests that most victims of snakebite will have a moderate local reaction with mild systemic signs. Life-threatening consequences such as shock are unlikely. SIGNS AND SYMPTOMS Gold and Wingert describe the signs and symptoms associated with an envenomated snakebite: "Panic is the most common reaction to a snakebite. As a result, the victim may become emotionally unstable with thoughts of imminent death, or conversely, the victim may enter a state of extreme lethargy and withdrawal. Fear may cause such symptoms as nausea, vomiting, diarrhea, dizziness, fainting, tachycardia [rapid hert rate], and cold, clammy skin. It is important that autonomic [flight or fight] reactions not be mistaken for systemic symptoms and signs resulting from a bite. Such an error could lead to unwarranted treatment. The primary local symptoms and signs of most pit viper envenomations are fang punctures, pain, edema [swelling], and erythema [redness] or ecchymoses [bruising] of the bite site and adjacent tissues. There may be one or more puncture wounds, depending on the number of fangs the snake had, the accuracy of the strike, and the number of strikes inflicted. Superficial lacerations produced by fangs do not usually result in envenomation, because the discharge orifice of the fang lies slightly proximal to the tip. Teeth marks, other than fang punctures, may or may not be present. There may be moderate pain in or around the local bite site in about 90% of pit viper envenomations. Exceptions are the bites from the Mojave rattlesnake and the speckled rattlesnake, which cause little or no pain. ...The pain, which had been described as sharp and burning in character, usually develops within 5 minutes after inoculation [injection] of the venom. Edema and erythema or ecchymoses are characteristic of pit viper envenomation and usually occur within 30 minutes of the bite, evolving both proximally and distally as the venom spreads. If edema and erythema have not manifested within 8 hours after a snakebite, it is generally safe to assume that the patient has not been envenomated. Frequently, there are signs of lymphangitis [inflammation of the lymphatic system] with tender regional lymphadenopathy [disease of the lymph nodes]. Frequent systemic manifestations after bites by eastern, timber, and western diamondback rattlesnakes are perioral parathesias extending to the face and scalp with tingling of the fingertips and toes. According to Russell, the most frequent diagnostic findings after bites by the Pacific rattlesnake are complaints of a 'minty,' 'rubbery', or 'metallic' taste in the mouth and 'tingling of the lips.' ...Skeletal muscle fasciculations [tics, spasms] in the bitten area, face, neck, and back may occasionally become generalized." Russell describes the effects of coral snake envenomation, "The bite is usually associated with some pain, although it may be minor and transitory in nature. Swelling is either absent or very minor. Parathesia [abnormal sensation] is sometimes noted around the bitten area, and some weakness of the part may become evident within several hours of the poisoning. The patient may complain of drowsiness, apprehension, and weakness. Muscular incoordination may develop, and muscle fasciculations [tics, spasms] and tremor of the tongue may be seen. Increased salivation and difficulties in swallowing and phonation [speech pronunciation], as well as visual disturbances, respiratory distress and failure, a bulbar [brainstem] type of paralysis, convulsions, and shock may develop." FIELD TREATMENT Now, what about treatment? What do you do if you or a member of your party becomes one of the unfortunate few to actually get bitten? The first thing is to remain calm. Remember, snakebite is not usually deadly in spite of all the hype about it. Even without treatment you will almost certainly recover. If you can identify the snake do so. If it is dead, take it with you to the hospital in a safe container to be sure of getting the right antivenin. Do not risk more bites in order to kill it. Remember the first rule of rescue: Do not create any more victims or risk further injury to the current victim. Trained first aiders base their treatment of patients on a protocol: a simplified set of procedures. We describe below two different protocols for the treatment of snakebite. A Wilderness Protocol The following treatment protocol is provided by Jeff Isaac and Peter Goth in The Outward Bound Wilderness First Aid Handbook, Lyons and Burford, 1991. This same protocol is taught to Wilderness First Responders and Wilderness Emergency Medical Technicians certified by the National Association for Search and Rescue: "Transport the patient as quickly as possible to antivenin (antidote). Although local discomfort may be severe, systemic signs and symptoms may be delayed for two to six hours following the bite. Walking your patient out is reasonably safe unless severe signs and symptoms occur. It is also significantly faster than trying a carry. Splint the affected part if possible. Expect swelling. Remove constricting items such as rings, bracelets, and clothing from the bitten extremity. Do not delay. Immediately following the bite of a snake thought to be poisonous, evacuation should be started. It can always be slowed down or cancelled if it becomes obvious that envenomation did not occur, or the snake is not poisonous. Most medical experts agree that traditional field treatments such as tourniquets, pressure dressing, ice packs, and "cut and suck" snakebite kits are generally ineffective and are possibly dangerous. Poisonous snakebite is one of those conditions that you cannot treat in the field. Don't waste valuable time trying." Boy, this is an awfully simple protocol! Doesn't seem to leave much for the first aider with an anxious desire to do something to occupy himself with. Well, at least they suggest you could make a nice splint. Actually, a first responder, EMT, or other trained person would know that there would be a number of other steps to field treatment that were not explicitly stated in this protocol. He might want to evaluate the patient's ABC's, take a history, record the time and events associated with the bite, thoroughly evaluate and document the chief complaint, conduct a physical exam, develop a plan for treatment and evacuation, and begin recording a regular series of vitals. He would also record all changes in signs and symptoms with the time that they occurred. None of these activities, however, would be allowed to interfere with moving the patient to definitive care (antivenin). Folks with a lesser set of skills would want to do what they could. As part of the history, the first aider should ask whether the patient has (a) asthma, hay fever, hives, or other allergies, (b) allergic reactions upon exposure to horses, or (c) prior injections of horse serum. The two antivenins in use in North America are both raised in horses, and patients with allergies to horses or horse serum can exhibit adverse reactions (see the discussion of hospital care below). The first aider should also ask whether the patient has been bitten by venomous snakes in the past, and, if so, whether he received antivenin and what the reaction to it was. Finally he should inquire when the patient last received a tetanus booster. Don't forget to wear rubber gloves when handling patients, for your safety and theirs. Playtex dishwashing gloves are a good choice for wilderness use, but disposable latex surgeon's gloves work fine too. If it is necessary to assist a patient's respirations, use a pocket mask. If the group is sufficiently large, it might be best to send two runners ahead to summon aid. At the very least, it would be nice to have an ambulance waiting at the trailhead. There is a maxim in wilderness first aid: move the patient to treatment, and move treatment to the patient. The best evacuation strategies will cause both of these things to happen simultaneously. If it is going to be more than 1 hour to hospital treatment, you may choose to rinse and disinfect the wound. More on how to do this follows below. An Urban Protocol The following more elaborate protocol is taken from the -Emergency Medical Technician 1A Protocols- for Fresno County in California. The protocol is designed for EMS personnel in an urban setting: "I. Priorities A. Assessment. Vital signs, site of wound, measure the circumference of the extremity, mark and record, note extent of swelling and record time. B. Keep patient quiet and reassure. If snake is available and dead, place in a secure container and bring to the emergency department. Use caution. Do not engage in a search for the snake. C. Code 3 transport [lights, siren] is indicated for patients in shock, uncontrolled bleeding or with concurrent severe injuries. Code 2 [normal driving, no lights, siren] transport for patients with stable vital signs without immediate life threat. [Folks that choose to transport a snakebite victim by personal auto to a hospital should note these instructions. Life-threatening systemic reactions are rare with snakebite, so safe driving within the speed limit is the way to go. Given the amount of panic associated with snakebite, it might be best to allow an ambulance transport the patient, and thereby reduce the risk of an automobile accident] II. Treatment A. Oxygen 6 L/min by nasal cannula. [If not trained in O2 delivery, then don't do this, RP] B. Apply elastic bandage 2-5 inches proximal to the bite if transport >10 minutes. Do not apply to hand or foot. No other tourniquet should be used. This should be applied to a tightness which allows you to slip one finger underneath. C. Immobilize affected extremity at or slightly below the level of the heart. D. Keep patient at rest. E. Mark area of swelling with pen line and record time. III. Further Evaluation A. If the snake was an exotic pet or zoo animal (e.g. coral snake, cobra, krait), neurotoxic symptoms may precede local reactions. Observe for mental status change, respiratory depression, convulsions, or paralysis. B. Do not allow any person to apply ice or cooling. Do not allow incision of the wound. C. The best course of action following envenomation is rapid transport to the emergency department where intravenous antivenin can be administered. D. Reassure patient. Mortality from snakebite is rare, particularly in young, healthy patients." Once again, this protocol does not mention all the neat things that trained EMS folks do for every patient. See the discussion following the wilderness protocol above. So two quite different approaches. One, designed for the wilderness, allows the patient to walk toward treatment. The other, designed for an urban setting with ready access to the EMS system, had the patient remain at rest, with the wound immobilized at or below the level of the heart. Which to follow? It is up to you to decide. But, a few comments that may help are listed below. FIELD TREATMENT: AREAS OF DISAGREEMENT Keep the Patient Immobilized, Wound at or below Level of Heart We described one field treatment procedure, designed for the wilderness, that allows the patient to walk toward treatment. The other, designed for an urban setting with ready access to the EMS system, required the patient remain at rest, with the wound immobilized at or below the level of the heart. In the urban setting, nothing is to be lost by the "keep patient at rest" approach. But in deciding what to do where help is an hour or more away, here are a few thoughts: (1) Antivenin is the definitive therapy for snakebite. Kurecki and Brownlee say, "Remember, based on the current literature, the single most effective course of action following a pit viper bite is rapid transport to an emergency department because the intravenous administration of antivenin remains the definitive and only therapy of proven value. The best first aid is a set of car keys." (2) The systemic reactions to snakebite are often delayed, giving a window that can be used to have the patient aid in his own rescue. Here is what Gold and Wingert say, "Several hours usually elapse after the bite before the severe toxic effects of the venom ensue. According to Parrish [Am J Med Sci, 1963, 245:129-41.], of 138 people who died from snakebites over a 10-year period, only 4% died within 1 hour and only 17% died within 6 hours. The majority (64%) died 6 to 48 hours after the bite. Victims of snakebites who received medical attention within the first 2 hours after being bitten have an excellent chance of survival." (3) There is little evidence in the literature that activity can worsen the outcome associated with snakebite (Keith Conover, personal communication). (4) There is little evidence in the literature that keeping the bitten extremity at or below the level of the heart has an effect on the outcome due to snakebite (Keith Conover, personal communication). (5) Evacuating a patient from the wilderness who is kept at rest necessitates a BIG rescue effort. It poses a potential risk to the rescuers themselves. (6) Waiting for a big rescue to be organized and executed could delay getting the patient to antivenin. (7) There is a tradition of self-rescue in mountaineering and other backcountry sports. Constriction Bands Most authorities agree that a constriction band may be of benefit. Here is what Gold and Wingert say, "If the anticipated delay in treatment is several hours and evaluation is done within 5 minutes of the snakebite, a constriction band may be applied about 5 cm above the bite or just proximal to the closest joint. The band should be tight enough to occlude lymphatic flow, yet loose enough so as not to impede arterial or venous circulation. The pulses distal to the bite should be palpated frequently to ascertain flow, and the band should be loosened, but not removed, if too tight." A constriction band is not a tourniquet!! If you are not confident that you can assess vascular function in an extremity, then you should not carry out this procedure. Swelling will cause this band to become tighter. It is going to require constant monitoring, and the band will have to be loosened as necessary. Forget to monitor or fail to properly assess vascular function, and you could cause permanent disability. Do not apply a constriction band directly to a digit, foot, or hand. Wound Cleaning The two protocols listed in the section on treatment do not mention cleaning the bite wound. However, if it is going to be an hour or two to get the patient to the hospital, you might consider cleaning the wound. Here is what Wilkinson in MFM says, "The skin should be washed and swabbed with an antiseptic. (Such obvious measures to reduce contamination are frequently neglected, resulting in infections which are responsible for a large part of the residual damage from snake bites. The bacteria that cause tetanus and gas gangrene have both been isolated from the mouths of poisonous snakes.)" Providone-iodine solution (10% in water, trade name Betadine) diluted 1:10 in clean water to make a 1% final concentration makes a fine antiseptic solution. Extractor Devices The Sawyer's Extractor is a spring-loaded piston that attaches to any of several sizes of cylindrical vacuum chambers. Although neither of the two treatment protocols above suggest its use, many authorities suggest it might be useful. Gold and Wingert state, "A number of field studies have shown that a Sawyer's Extractor (Sawyer's Products, Safety Harbor, Fla), which provides about one atmosphere of negative pressure, is effective in extracting venom from the bite site, provided it is applied within the first 5 minutes after the victim is bitten. Suction should then be continued during the first 30 to 60 minutes after a bite." FIELD TREATMENT: 'THERAPIES' TO AVOID Incisions Don't use them. Gold and Wingert say, "The use of ice, tourniquets, incision and suction, and electric shock therapy as part of emergency field therapy should be strictly discouraged." Similarly, Kurecki and Brownlee say, "The complications of incision and suction, especially in the hands of the untrained person who does not know the anatomy of the body, include damage to underlying structures, vascular compromise to the extremity, and infection. The blade in a snakebite kit is of sufficient size and quality to damage underlying blood vessels, nerves, tendons, and muscles. It has never been shown in a clinical trial that incision and suction improves motality, although morbidity through improper incision is increased." If you have one of those little green snakebite kits, you might as well discard it. The little sharp knives are dangerous to use, and the suction developed by the little rubber cups is insufficient to be of benefit. See the discussion of extractor devices above. While you are discarding dangerous implements from your first aid kit, you might as well throw out those ammonia inhalants and salt tablets too. Oral Suction Do not try to suck venom from a wound by mouth. You might cause a severe infection in the wound due to bacteria from your mouth. And, you do not want to take a risk of absorbing venom through a cut, or a sore, or bleeding gums. Finally, given the risk of blood-borne pathogens such as hepatitis and AIDS, putting your mouth to a wound on another person is an unwise practice. It is worth repeating here: use gloves when handling patients, particularly if they have a wound. Use a pocket mask if you assist respirations. Tourniquets Don't use them. Gold and Wingert say, "The use of ice, tourniquets, incision and suction, and electric shock therapy as part of emergency field therapy should be strictly discouraged. Dart [Dart, R. and Russell, F.E.-Animal Poisoning-. in Principles of Critical Care. Hall, Schmidt and Wood (eds). New York, McGraw-Hill, 1992, 2163-71.] studied 94 snakebite victims at University of Arizona. Of 18 patients who had used a tourniquet, problems developed in 8; 6 had tissue loss, and 2 had permanent disability resulting directly from the use of a tourniquet." See the discussion above of constriction bands. Compression Wraps In North America, don't use them. For the same reasons as tourniquets. In Australia, the bites of the elapids they have there have a greater potential for fatal outcome. Physicians there have used compression wraps with success. Inquire about local procedures when you travel. Electrical shock Don't use it. Electrical shock was tried experimentally for a time, and several portable devices were developed. These still turn up in use from time to time at rattlesnake roundups and the like. No research data ever emerged that supported the use of electric shock. Ice or Cold Packs Don't use them. Here is what James Wilkerson says in Medicine for Mountaineering (3rd Ed): "Packing an extremity bitten by a poisonous snake in ice or snow probably would not be possible in most wilderness situations because snakes do not inhabit areas where ice and snow are available. However, such therapy for poisonous snake bite has been recommended in the past. The basis of such therapy was the assumption that the active components of snake venom were enzymes, the activity of which would be reduced by cooling. However, subsequent studies have determined that most of the toxins in snake venom are peptides, which are not inactivated by cooling. Additionally, since snakes are cold blooded animals, their enzymes remain active at temperatures at which a warm blooded human's defenses are immobilized. Furthermore, some enzymes are driven deeper into warmer tissues by cooling the skin. Few physicians advocate local cold therapy; even fewer would deny that its use outside the hospital as a technique for emergency care has caused the loss of many limbs." Cold causes increased local tissue destruction when applied to North American pit viper bites. See the following references: Sullivan JB Jr, Wingert WA. Reptile Bites. in Auerbach PS, Geehr EC, Ed Management of wilderness and environmental emergencies. 2nd ed. St. Louis: C.V. Mosby Co., 1989:479-511. Gill KA Jr. The evaluation of cryotherapy in the treatment of snake envenomation. So Med J 1968;63:552-6. Durand LS, Rodeheaver GT, Edlich RF. Poisoning by pit vipers. W Va Med J 1982;78(7):162-7. HOSPITAL CARE The definitive care in the hospital will be i.v. administration of antivenin. The number of vials of antivenin administered will depend on the severity of the envenomation. Snakebite patients who were not envenomated or who were bitten by a copperhead may not receive antivenin. There are two antivenins in common use in the United States. Both are manufactured by Wyeth-Ayerst Laboratories and are created by injecting venom into horses, and then collecting the resulting immune serum. Antivenin (Crotalidae) Polyvalent is developed by injecting a mixture of the venoms of eastern diamondback, western diamondback, cascabel (tropical rattlesnake), and fer-de-lance into horses. This antivenin is used for treating the effects of bites from crotalids native to North, Central, and South America, as well as Japan and Korea. Antivenin (Micrurus fulvius) is developed by injecting the venom of the eastern coral snake into horses. It is used for treating the bites of both eastern and Arizona coral snakes. There is a potential for a dangerous reaction to antivenin in patients who have an allergy to horses or horse serum. For this reason antivenin is only administered in a hospital, and the physician makes every effort to rule out allergy before he administers the antivenin. The adverse consequences of antivenin administration in patients allergic to horses include shock, anaphylaxis, and serum sickness. If your physician desires more information on the two antivenins used for the treatment of North American snakebites, he can contact the manufacturer: Professional Services Wyeth-Ayerst Laboratories PO Box 8299 Philadelphia, PA 19101 (610) 688-4400, or (800) 950-5099 Also while in the hospital, the bite wound will be cleaned, and the patient will subjected a battery of laboratory tests. Any of a variety of drugs and i.v. fluids may be administered including D5W, saline, plasma, blood products, antiphylaxis agents, sedatives, analgesics, and antibiotics. The patient may receive a tetanus booster. Continuing wound care will include cleansing, and may include surgical treatment of the wound area. If movement or strength of an extremity is compromised, patients may receive physical therapy. COMPLICATIONS Downey, Omer and Moneim reported 68 complications in their study group of 36 snakebite victims. The most frequent was compartment syndrome (increased pressure within a closed body compartment, interfering with function), which occurred in 25 patients. All 25 received surgical intervention (fasciotomy). The breakdown of all complications was as follows: Compartment syndrome 25 Carpal tunnel syndrome 1 Reduced range of motion 9 Reduced sensation 4 Thrombosed digital artery 1 Wound infection 4 Tendon necrosis 1 Digit amputation 1 Abnormal coagulation studies 7 Thrombocytopenia 4 Postoperative anemia 4 Serum sickness 4 Hypotension 3 Pleural effusion 1 The length of hospital stay ranged from 1 to 31 days; the median was 5 days. GLOSSARY The definitions below are simplified; you would find more subtle and complex definitions in dictionaries of biology or medicine. anemia Abnormally low number of red blood cells in the blood. antivenin Antiserum used to treat the victims of snakebite. Manufactured by hyperimmunizing horses with snake venom. autonomic reaction Flight or fight reaction. bulbar Pertaining to the brainstem. Bulbar functions include the maintenance of heart rate and breathing. carpal tunnel syndrome coagulation Clotting of blood. compartment syndrome The effect of swelling within a closed body space. crepuscular Active at twilight. crotalid A member of the snake subfamily Crotalinae, the pit vipers. distal Toward the periphery of the body and away from the central axis. Opposite: proximal. ecchymoses Bruising. edema Swelling elapid A member of the snake family Elapidae, which includes the coral snakes and other venomous snakes with immovable hollow fangs at the front of the mouth. envenomation Injection of venom. erythema Redness. fasciculations Tics or spasms. hemolytic toxin Poison which attacks the blood. hybrid The offspring deriving from the mating of members of two different species. hypotension Low blood pressure. inoculation Injection. lymphadenopathy Disease of the lymph nodes. lymphangitis Inflammation of the lymph nodes. nasal cannula A hoop of plactic tubing with two open nozzles which insert into the nostrils. Used for the delivery of oxygen. necrosis Death of tissue. neurotoxin Poison which attacks nervous tissue. parathesias Abnormal sensations. perioral Around the mouth. phonation Speech pronunciation. pleural effusion Escape of fluid into the space outside the lungs and inside the chest wall. prophylaxis Prevention. protocol Procedure or rules of action. proximal In the direction of the central axis of the body. Opposite: Distal. serum The watery component of blood. serum sickness An allergic reaction after administration of a foreign serum. shock The life-threatening systemic reaction to inadequate perfusion of the tissue with oxygenated blood. Not the same as an autonomic reaction. tachycardia Fast heart rate. tetanus An infectious disease due to the toxin of tetanus bacteria growing at the site of an injury. thombosed Containing a blood clot (a thrombosis). thrombocytopenia Abnormal decrease in the number of blood platelets. toxin A poison. Syn: venom. venom A poisonous secretion of certain plants and animals. Syn: toxin. DISCLAIMER This FAQ does not constitute professional medical advice. It is merely a compilation of information available in the literature. If you need professional medical advice on snakebite or any other topic, consult your physician. ----------------------------------------------------------- (Written by Hal Lillywhite. Last update: 14 February 1994) (Revised by Richard Penny. Last update: 9 August 1995) >From "Last Chance to See" "Oh, you don't have to worry about identifying Tasmanian snakes. They're all poisonous." ... "So what do we do if we get bitten by something deadly, then?" I asked. He blinked at me as if I were stupid 'Well what do you think you do?' he said. 'You die of course. That's what deadly means.' 'But what about cutting open the wound and sucking out the poison?' I asked. 'Rather you than me,' he said. 'I wouldn't want a mouthful of poison. All those blood vessels beneath the tongue are very close to the surface so the poison goes straight into the bloodstream. That's assuming you get much of the poison out, which you probably couldn't. And in a place like Komodo it means you'd probably quickly have a seriously infected wound to contend with as well as a leg full of poison. Septicaemia, gangrene, you name it. It'll kill you.' 'What about a tourniquet?' 'Fine if you don't mind having your leg off afterwards. You'd have to because it would be dead. And if you can find anyone in that part of Indonesia who you'd trust to take your leg off then you are a braver man than me. No, I'll tell you: the only thing you can do is apply a pressure bandage direct to the wound and wrap up the whole leg up tightly, but not too tightly. Slow the blood flow but don't cut it off or you'll lose the leg. Keep the leg or whatever bit of you it is you've been bitten in, lower than your heart and your head. Keep very, very still, breathe slowly and get to a doctor immediately. If you're in Komodo that mean a couple of days, by which time you'll be well dead. 'The only answer, and I mean this quite seriously, is don't get bitten. There is no reason why you should. ... No, the things you really need to worry about are the marine creatures.' 'What?' 'Scorpion fish, stonefish, sea snakes. Much more poisonous than anything on land. Get stung by a stone fish and the pain alone can kill you. People drown themselves just to stop the pain.' ... 'Is there anything you do like?' 'Hydroponics.' 'No I mean are there any venomous creature you're particularly fond of?' He looked out of the window for a moment. 'There was,' he said, 'but she left me.' --Douglas Adams, Chapter 2 "Here Be Chickens," in Last Chance to See An older copy of this file (check last modified dates) can be found at: ftp: sunSITE.unc.edu: pub/academic/agriculture/sustainable_agriculture/health-safety-FAQs MEDICINE FOR MOUNTAINEERING. Forth Edition. Edited by James. A. Wilkerson. MD. The Mountaineers. ISBN: 0-89886-331-7 SPIDERS Almost all spiders produce toxic venoms, but their fangs are too small and weak to penetrate the skin, the venom is too weak, of the volume of venom is too small to pose a significant threat for humans. The black widow (Latrodectus mactans) is the only spider found in the United States that is capable of routinely producing serious illness by its bite. The "tarantula" native to the U.S. Southwest bites only after extreme provocation. Its weak and ineffective fangs can only penetrate thin skin, such as that on the sides of the fingers; the effects of the bite are no worse than an insect sting. In other parts of the world are spiders that can cause severe, even fatal poisoning in humans. Other species of Latrodectus produce effects similar to the black widow. The bites of large, hairy tarantulas found in areas such as Brazil or Peru can have similar results. The Sydney funnel web spider, reportedly limited in distribution to the area within 100 miles of Sydney, Australia, is capable of inflicting a bite that can be lethal for healthy young adults. Some spiders, such as the brown, or violin, spider (Loxoseeles recluse) inflict bites that occasionally cause extensive damage at the site, but usually have less severe generalized effects. The jumping spider (Phidippus) is the most common biting spider in the United States. Bites by this spider, trapdoor spiders, orbweavers, and spiders of the Chiracanthium species, such as the garden spider, commonly produce local reactions that ulcerate and less often produce systemic symptoms. However, individuals with these bites almost never require hospitalization. Spiders usually cling to the site of the bite. (If the spider can not be found, some other arachnid, such as a bedbug, should be suspected.) Anyone who has been bitten should take the spider to be identified. Rarely, an individual may be bitten repeatedly by a relatively harmless spider or insect and develop an allergy to the toxin produced by that species. Subsequent bites can produce severe, even fatal allergic reactions. Fortunately such events are rare. The treatment for such reactions is identical to the treatment for allergic reactions to Insect stings. BLACK WIDOW SPIDER BITES The female black widow typically is coal black and has a prominent, spherical abdomen that may be as large as one-half inch (1.25 cm) in diameter. This appearance is so distinctive that finding the characteristic markings on the undersurface of the abdomen is rarely necessary. The typical markings consist of red or orange figures that usually resemble an hourglass, but may be round, broken into two figures, or have some other configuration. Markings of the same color but in varying patterns are sometimes present on the back, although only the undersurface markings are considered characteristic. In some southwestern states black widow spiders have irregular white patches on their abdomens. Different species of Latrodectus in other countries have a similar appearance. (fbe mate is smaller, has a brown color, and is harmless.) The black widow weaves a coarse, crudely constructed web in dark corners, both indoors and out. Almost half the black widow bites reported in the medical literature in the first four decades of this century were inflicted on the male genitalia by spiders On the underside of outdoor toilet seats. However, this spider is timid and would rather run than attack an intruder. Thirty to forty years ago five to ten deaths a year resulted from black widow spider bites, although they were limited almost entirely to small children or elderly individuals in poor health. Recognition and treatment of such bites has improved so much that deaths are rare within the United States. (Bites in children weighing thirty pounds or less would still have a mortality of about fifty percent if untreated.) In healthy adults, black widow spider bites cause painful muscle spasms and prostration for two to four days, but complete recovery essentially always follows. Antivenin treatment is not recommended for adults. The bite may feel like a pin prick, may produce a mild burning, or may not be noticed at all. Small puncture wounds, slight redness, or no visible marks may be found at the site of the bite. Within about fifteen minutes painful muscle cramps develop at the point of the bite and rapidly spread to involve the entire body. The characteristic pattern of spread is by continuity. From a bite on the forearm the cramps would spread to the upper arm, to the shoulder, and over the chest to involve the rest of the body, including the legs. The abdominal muscles are characteristically rigid and hard, although the abdomen is not tender. Weakness and tremors are also present. A typical subject is anxious and restless. A feeble pulse and cold, clammy skin suggest shock; labored breathing, slurred speech, impaired coordination, mild stupor, and rare convulsions (in children) suggest disease involving the brain, Bitten individuals are often covered with perspiration; dizziness, nausea, and vomiting are common. If the spider or its bite have not been observed, the signs and symptoms may lead to an erroneous diagnosis of an acute abdominal emergency. Symptoms typically increase in severity for several hours, occasionally as long as twenty-four hours, and then gradually subside. After two or three days essentially all symptoms disappear, although a few minor residua may persist for weeks or months. Treatment consists of efforts to relieve the painful muscle spasms and antivenin for small children. No treatment at all should be directed to the site of the bite, with the possible exception of applying an ice cube to relieve pain. Incision and suction is damaging and useless and should not be performed. Essentially nothing can be done outside a hospital; small children must be hospitalized. Antivenin, produced in the United States by Merck Sharp & Dohme, and the drugs to control spasms are rarely available anywhere else. The antivenin is prepared in horses and should not be given to persons allergic to horse serum. It is usually not administered to healthy adults between the ages of sixteen and sixty, and only to individuals of small body size with severe symptoms who are twelve to fifteen years old. Instructions with the vial of antiserum should be followed. Muscle spasms may be relieved by periodic injections of 10 cc of a ten percent calcium gluconate solution or 10 cc of methocarbamol, but these are rarely available outside a hospital. A tranquilizer (diazepam) may help relieve less severe muscle spasms; hot baths are occasionally helpful. Strong analgesics are helpful but rarely provide complete pain relief. BROWN SPIDER BITES The brown, or violin, spider (Loxosceles recluse) more recently labeled the "brown recluse spider," has received attention as the cause of "necrotic arachnidism." Following the bite of this spider, a blister appears, and is surrounded by an area of intense inflammation about one-half inch (1.25 cm) in diameter. Pain is mild at first but may become quite severe within about eight hours. Over the next ten to fourteen days the blister ruptures and the involved skin turns dark brown or black. Eventually the dead, black tissue drops away, leaving a crater that heals with scarring. A few individuals have large skin losses that require grafts to cover the defect. Some children have lost considerable portions of the face. Such events have attracted great notoriety for this spider, even though much smaller wounds are far more typical. Bites are attributed to Loxosceles recluse (incorrectly) well outside of its habitat, which is limited to the southeastern and south-central portion of the United States and ends at the Texas-New Mexico border. Generalized symptoms that may appear within thirty-six hours of the bite include chills and fever, nausea and vomiting, joint pain, and a skin rash or hives. With severe reactions, red blood cells are broken down (hemolysis) and platelets are destroyed (thrombocytopenia), which can result in a significant anemia and bleeding tendency. Rare fatalities have occurred, mostly in children. Essentially nothing can be done for such bites in a wilderness situation unless appropriate injectable medications are carried along. If the person can be hospitalized within less than eight hours, the site of the bite can be surgically excised. Such therapy should be reserved for bites from spiders clearly identifiable as L. recluse, so the spider must be captured (intact if possible) and brought to the hospital to be identified. After eight hours the area involved may be too large to be excised. Corticosteroids may also be administered. One recommended program is 4 mg of dexamethasone, administered intramuscularly every six hours until the reaction starts to subside, and then in tapered doses. Others include injection of hydrocortisone beneath the bite and the administration of dapsone. Nothing is very satisfactory. SCORPION STINGS Scorpions are found throughout most of the United States, but the species lethal for man, Centruroides, are limited to Arizona, New Mexico, Texas, southern California, and northern Mexico. In these areas scorpions are a significant problem. Sixty-nine deaths resulted from scorpion stings in Arizona between 1929 and 1954. During the same period, only twenty deaths resulted from poisonous snake bites. With improved medical management of the complications of scorpion stings, no deaths have occurred in Arizona for twenty years. Scorpions are eight-legged arachnids that range in length from three to eight inches (7.5 to 20 cm) and have a rather plump body, thin tail, and large pinchers. They are found in dry climates under rocks and logs, buried in the sand, in accumulations of lumber, bricks, or brush, and in the attics, walls, or understructures of houses or deserted buildings, The problems with scorpions in Arizona are clearly related to their tendency to live in the vicinity of human habitation where children are frequently playing. Stings can be avoided by exercising care when picking up stones, logs, or similar objects under which scorpions hide during the day. Since scorpions are nocturnal, walking barefoot after dark is inadvisable. Shoes and clothing should be shaken vigorously before dressing in the morning, particularly when camping outdoors. The lethal species of scorpions are often found under loose bark or around old tree stumps. They have a yellow to greenish yellow color and can be distinguished from other species by a small, knoblike projection at the base of their stingers. Adults measure three inches (7.5 cm) in length and three-eighths inch (I cm) in width. One subspecies has two irregular dark stripes down its back. The sting of a nonlethal scorpion has been described as similar to that of a wasp or hornet, although usually somewhat more severe, and should be treated in an identical manner. (Scorpion venom is not identical to insect venom, and individuals allergic to insect stings usually are not allergic to scorpion stings.) Lethal scorpion stings are more painful, but fatalities have been limited almost entirely to small children. Initially the sting of a scorpion of one of the lethal species produces only a pricking sensation and may not be noticed. Nothing can be seen at the site of the sting. (Swelling and red or purple discoloration are indications that the sting has been inflicted by a nonlethal species.) Pain follows in five to sixty minutes and may be quite severe. The sting site is quite sensitive to touch and is the last part of the body to recover. Tapping the site produces a painful tingling or burning sensation that travels up the extremity toward the body. (Apparently stings by other species of scorpions can occasionally produce a similar sensation.) Sensitivity may persistas long as ten days, although other symptoms usually disappear within ten hours. Individuals who have been stung typically are extremely restless and jittery. Young children writhe, jerk, or flail about in a bizarre manner that suggests a convulsion. Their movements are completely involuntary. However, in spite of their constantly moving bodies, the children can talk. Although they appear to be writhing in pain, they usually state that they do not hurt. Convulsions have been described, but the true nature of these events is questionable. Visual disturbances such as roving eye movements or a fluttering type of movement known as nystagmus are common. Occasionally a child complains that he can not see, but nothing abnormal can be found when examining his eyes, and sight returns spontaneously in a few minutes. Children under six years of age may develop respiratory problems such as wheezing and stridor, and a few may need assisted respiration. Persons who have been stung typically have an elevated blood pressure, which may be an important diagnostic sign since hypertension is rare in children. The blood pressure usually returns to normal within four to six hours and becomes life-threatening only in infants. Elderly individuals with preexisting health problems and small children stung by one of the lethal scorpion species should be taken to a hospital. Only a medical facility of that sophistication has the equipment and supplies necessary to monitor these individuals and deal with any complications that may arise. An ice cube applied to the site of the sting may help reduce pain, but no other therapy is possible outside a hospital. In locations such as the Grand Canyon, where prompt evacuation is not possible, diazepam can be given to children for control of the involuntary movements. Other countries have species of lethal scorpions much more deadly than those in the Southwestern United States. Mexico reportedly has had as many as 76,000 scorpion stings resulting in 1,500 deaths in a single year. The stings of such scorpions must be treated with antivenin, which is rarely obtainable outside a hospital, particularly by someone who does not speak the country's language. Death from the stings of such scorpions is usually the result of sudden, very severe high blood pressure. Adrenergic blocking agents such as propranolol may be an effective method for treating such stings and probably should be carried by visitors to the countries where such lethal species of scorpions exist. //no more// ALLERGIC REACTIONS TO INSECT STINGS Between fifty and one hundred deaths result annually from allergic reactions to Hymenoptera stings (bees, wasps, hornets, and fire ants) in the United States, more than the deaths from rabies, poisonous snakes, spiders, and scorpions combined. Approximately one of every two hundred people in the United States has experienced a severe reaction to such stings. Potentially fatal reactions can be prevented or successfully treated in individuals known to have such allergies, but many deaths still occur in persons whose allergic status had not been previously recognized. The problem of allergies and the severe, potentially lethal allergic reactions known as "anaphylactic shock" are discussed in Chapter Twenty, "Allergies." An individual allergic to insect stings usually experiences milder allergic reactions before having a potentially fatal reaction. Two types of nonlethal reactions occur: local reactions and systemic reactions. Local reactions are characterized b severe swelling limited to the limb or portion of the limb that is the site of the insect sting. Almost all insect stings are associated with some swelling, but the area of swelling is usually three inches (7.5 cm) or less in diameter. With severe local reactions, a major portion of an extremity, such as the entire forearm, is swollen, and may be painful, associated with itching, or mildly discolored. Systemic reactions occur in areas of the body some distance from the site of the Sting. Most typical are hives, which may be scattered over much of the body. Generalized itching or reddening of the skin may also occur. Persons with more severe reactions may have hypotension (low blood pressure) and difficulty breathing. (Clearly, the last two reactions could be fatal if severe.) Investigators of insect hypersensitivity reactions have recommended that individuals who have had a systemic reaction to an insect sting undergo skin testing with Hymenoptera venoms. (If the results of skin tests are inconclusive, more sophisticated measurement of venom-specific IgE antibodies by the radioallergosorbent procedure can be carried out.) About half of the people who have had a systemic reaction and also have a positive skin test would be expected to have a severe, possibly fatal reaction if stung again. Desensitization with purified insect venoms-not whole-body extracts-is recommend for these individuals. (In one recent study of children who had experienced an anaphylactic reaction following a sting, only nine percent of subsequent accidental stings led to severe reactions. None of the reactions were more severe than the original reactions, which led to the conclusion that immunotherapy was unnecessary for such individuals.) Desensitization can be a drawn-out, uncomfortable procedure but also can be life-saving. Starting with very small quantities, increasingly larger amounts of the insect venoms are injected subcutaneously until the allergic reaction is "neutralized." The individual is still allergic to the Hymenoptera venoms, but the antibod'ble for producing the allergic reactions are "used up" by the repeated les response I injections of the material with which they react. Generally, even after successful desensitization, injections must be continued at approximately monthly intervals for years or indefinitely. If the desensitization injections are stopped, the former allergic condition often reappears. Desensitization must be carried out under the close supervision of a physician experienced with the procedure. Severe, life-threatening allergic reactions to the desensitization injections may occur, and a physician must be on hand to deal with them. However, a physician who is standing by watching for a reaction can treat it effectively. Allergic reactions to insect stings in a wilderness environment without a physician in attendance are a far greater threat. Desensitization, or even skin testing, is not recommended for individuals who have large local reactions because these are rarely followed by systemic reactions. However, carrying epinephrine (adrenaline) is recommended for individuals who have had either type of reaction. For individuals experiencing an anaphylactic reaction, 0.3 cc of a 1:1,000 solution of epinephrine should be injected subcutaneously as soon as symptoms are detected. Second (and sometimes third) injections are often needed at intervals of twelve to fifteen minutes. Rock climbers and some other wilderness users who have systemic allergic reactions to insect stings have a unique risk of fatal reactions because they are subject to stings in locations, such as rock walls, where they can not be immediately treated by others and only with difficulty by themselves. Such persons should seriously consider desensitization now that purified venom preparations, which make that procedure so much more reliable, are available. They also must be prepared to treat an anaphylactic reaction at any time. From: WWWbstr@aol.com Date: Tue, 13 Aug 1996 18:18:59 -0400 Message-ID: <firstname.lastname@example.org> Subject: DW - Snakebite statistics I just finished reading the DW on snakes; found it very useful but had a minor quibble. I hope I'm commenting on the current version - my newsreader (AOL 3.0) won't let me open or download it (or the water filter / giardia DW) because of size; I had to resort to the HTML version pointed to from the AT homepage. There was an excerpt from the article by Curry et al, studying 85 bites treated at a single center. A little further down: > Remember, according to Curry, 74.4% of bites are to the upper extremities. Three points: 1) I don't think 85 samples justifies reporting to 0.1%. 2) Curry notes that only 27% of the upper extremity bites were legitimate. Thus the proportion of _legitimate_ bites which are to upper extremities drops to the general neighborhood of 20% (assuming that nobody made up a story about firewood rather than admitting that he got himself bitten by being stupid). 3) There was no indication in the excerpt of how the treatment center was selected. If it is located in an area with, say, an unusually large number of macho idiots who get drunk and pick up "pet" snakes, the data would obviously be skewed. Likewise, a center from an area with a lot of rock climbers would probably show an unusually large number of legitimate upper extremity bites. IMHO, the study sheds interesting light on the subject but one should avoid any statement which might seem to extrapolate its data to the full range of snakebite (otherwise, an alternate conclusion would be: "snakes don't bite women" - that might make an entertaining thread...). Anyway, thanks for distilling the wisdom; I just felt I had to comment on an apparent misuse of statistics. - Will Webster (on my way to get the OB 1st Aid Manual) **FAQ: Venomous Critters ** An interesting summary on poisonous snakes, spiders, lizards, and scorpions, with up-to-date treatment. Worth reading, and rather humorous besides. Especially good for those moving to the southwest or southeast! Venom Nation Vipers, spiders and scorpions. A traveler's guide to our poisonous pals. Within the United States there are five groups of dangerous venomous animals that travelers might expect to encounter: pit vipers, coral snakes, scorpions, spiders and lizards (two other groups - centipedes and stinging insects like bees, wasps and ants - are generally not lethal.) Which ones are the most poisonous? Any attempt at classification results in qualification. This much can be said: The venom of rattlesnakes is responsible for more deaths, more hospitalizations and more crippling injuries than the venom of any other animal in North America. Below is a field guide to each of the five venomous groups, how to avoid them - and what to do if it's just not your day. Pit Vipers - So called because of the heat-sensing "pit" or opening beneath each eye that's used to track prey in darkness, this family of snakes includes three species: Crotalus( the rattlesnakes, of which 32 species and 65-70 subspecies have been identified in the US alone), Agkistrodon (copperheads and cottonmouths) and Sistrurus (pigmy rattlers and massasaugas). Bites from any of the, even the most potent rattlesnakes, rarely result in death. Still, if you are bitten get to a hospital. Don't apply a tourniquet or ice. Don't use a snakebite kit. Don't cut the puncture wound and try to suck out the venom. In fact, there is no good first aid for rattlesnake bite. "We'd rather tell people that than have them doing the wrong thing and lose their life or an arm," said Boyer. If you must do something, she said, "elevate and immobilize the limb, rest quietly, and don't freak out." Most of the popular literature on snakebite is out of date, and some hospital emergency-room physicians may still attempt to use ice. Some may even want to do surgery. Don't let them. Almost all cases of amputation after snakebite are actually the result of using ice, a tourniquet or both. Surgery is necessary only in extremely rare cases. If you're not in an area where snakebite is common, insist that the doctors call the Regional Poison Control Center (listed on the inside cover of the phone book). The sole treatment is a 1950's era rattlesnake antivenom made from horse serum (antibodies derived from the blood of horses), which is reasonably effective in most cases. But almost everyone who is treated with rattlesnake antivenom can count on some level of serum sickness - a natural allergic reaction. Still, that is usually preferable to the effects of untreated snakebite. Boyer said, "It's a lousy, stinking product that causes a lot of problems, but there's nothing else around." The cure for snakebite is to avoid it. It's not that difficult. Snakes generally shun people. If you see one, move away from it. A rattlesnake can strike an object up to a distance equal to half it's body length. The largest rattler on record in the US was around seven feet long, so if you remain just four feet away from any snake you encounter, you can take photos, you can sing Pink Floyd songs, but you're unlikely to be bitten. Some people like to chop the head off a rattlesnake and take it with them. Bad idea. A rattlesnake can bite up to an hour after decapitation. A "spasm" from a dead snake will reflexively deliver the full load of venom and can be worse than a live snakebite. It's nature's way of telling you: Leave them be. The question most people ask: Am I going to die? The answer: Yes, but probably not today. While envenomation by a pit viper can result in the loss of a finger, hand, arm or leg, in the US it's not likely to be lethal. Coral Snakes Members of the family Elapidae include cobras, mambas, kraits, and coral snakes. There are two species of coral snakes in the US, the eastern coral snake and the Arizona coral snake. The eastern coral's venom is a powerful neurotoxin that, on occasion, has caused deaths. At first there may be no symptoms, and local injury is often small with little swelling or tissue damage. But within a few hours, the victim may experience a cascading sequence of symptoms, beginning with lethargy, nausea, weakness, and trembling or twitching. This leads to convulsions, paralysis, respiratory failure and, in some instances, death. No deaths from Arizona, or western corals have ever been reported. Coral snakes are brightly colored with borad bands that encircle the body, making a pattern beginning with a black snout; black, yellow, red, yellow, black, yellow, red, yellow. The yellow may appear white or ivory. Unlike rattlesnakes, coral snakes have round (not elliptical) pupils and fixed fangs. The Arizona coral snake lives in southern Arizona, the southwest corner of New Mexico and Texas. The eastern coral snake, which is larger can be found in North Carolina, South Carolina, Arkansas, Alabama, Georgia, Mississippi, Florida, Louisiana, and Texas. People have come to believe they can handle coral snakes with impunity because they won't bite. Some say they can even use a coral snake as a bracelet. The fact is that coral snakes bite unpredictably. It is difficult for a coral snake to bite a human, because of it's fixed fangs and small head (even in the larger eastern coral snakes). People often handle them for hours without incident, only to be bitten for the reasons that only a coral snake could tell you. Venom is delivered via grooves in the teeth, rather than injected by hypodermic action, which is why coral snakes like to hang on for awhile. If you are bitten, pull the snake off. The less time you give it, the less venom you get. A bite by an eastern coral snake is a major medical emergency. Get to a hospital immediately. There is a horse serum antivenom for the eastern coral snake, and it is the only effective treatment. No antivenom exists for the western coral, whose bite is usually not fatal. But hospital care is important, and a tetnus shot is probably a good idea. Scorpions Arthropods have been on earth more than 400 million years, but only one species in the US is potentially lethal, the bark scorpion. It is confined mostly to the southwest. Mexico is home to seven lethal species. Once you have seen a scorpion, you won't forget what it looks like; claws that snatch and a hooked stinger hovering on a five segment tail. They come in colors ranging from straw to pink to brown to black and in sizes from an inch or less to five inches. The most common in the southwest is also the largest, the giant hairy scorpion, but its venom is not considered dangerous. As a rule, specialists say, the thicker the claws, the less dangerous the scorpion; the viciously venomous ones usually have slim pincers. The bark scorpion is generally straw-colored with elongated tail segments - and slim pincers. It is only about an inch long at maturity. Bark scorpions are so called because they like to hide in the bark of trees. Unfortunately, they also like to hide in the drains of your sinks or in your shoes at night. They like any moist, dark, protected place. A sweaty shirt thrown on the floor might make an inviting hideout, too. The scorpion grips its prey with it's crablike claws and then whips its tail over its back to inflict a sting. (Scorpions do not bite.) As with snakes, 90 percent of stings are on hands or arms. Some first aid can help. Ice and acetaminophen are good for pain relief. Apply a single ice cube, 10 minutes on, 10 minutes off. (Don't immerse the wound in ice water.) If the victim is a child, a visit to the emergency room is in order. Bark scorpion venom contains at least five potent neurotoxins. Its sting is very painful, though the wound may not swell much at first. It is generally not life-threatening to healthy adults. The classic symptoms of a serious reaction, usually seen only in children, include uncontrollable thrashing of the arms and legs and roving eyes. Adults may experience mild twitching of the facial muscles, cramps, nausea and anxiety. Infants are especially at risk of respiratory failure. Though some 8,000 scorpion stings are reported in Arizona alone each year, there have been no fatalities since 1958. Although antivenom is given for scorpion stings in Mexico, none has been approved by the FDA for use in the U.S. Widow Spiders All five species in the United States, including the black, red and brown widows, are poisonous. Only females have fangs long enough to puncture human skin and inject venom. The black widow is shiny black with a body the size of a nickel and a red hourglass marking on its stomach. The hourglass may also be yellow or orange. Its characteristic web is tangled, strong, nd chaotic looking (like the fake spider web that people spread around at Halloween). They are found in any protected place indoors- closets, attics, basements - or outside, under woodpiles, animal burrows, barns and beneath ground cover. Mature females tend to stay in their webs. They don't prowl. The black widow lies in its web and bites when the web is disturbed. The classic human encounter involves a spider that spins its web back and forth across the the seat of an outhouse to catch flies that move back and forth through that opening. "More men and boys are bitten in outhouses because they have dangling appendages," Jude McNally said. Black widow spider venom is a powerful neurotoxin. There may be two puncture wounds and a pale coloring to the skin around them. Major pain begins in about half an hour, an ache that tends toward numbness. Systemic symptoms may take up to two hours to appear. Muscle pain near the bite spreads to the abdomen, back, and legs - or it may simply appear in those locations. Other symptoms include difficulty in breathing, muscle twitching, anxiety, swelling of the eyelids, headache and nausea. But don't wait for symptoms to appear. Go to the emergency room where you may receive muscle relaxants and narcotics for pain. An antivenom exists, but allergic reactions to it may be much more severe than the spider bite itself. It is recommended only for pregnant women or for cases involving hypertension, seizures or respiratory failure. Deaths are very rare; none have been recorded in the United States in more than 15 years. Brown Spider The 12 species in the US (out of more than 100 that are known) include the infamous brown recluse spiders and the Arizona brown spiders. All are seriously dangerous to humans. Called "violin spiders" because of violin shaped marking on the back, the brown spider's body is usually a half to a full inch in length. Their legs are two or three times as long as their bodies. Colorings can vary from gray to orange to rust to brown. Unlike other spiders, which have four pairs of eyes, browns have three pairs. Brown spiders range across the south and southwest and up through Iowa and Illinois (but no farther north than southern Wisconsin). They like to hide in dark corners indoors, or under objects or in the nests of animals outdoors. Their webs are dense, disorganized, sticky and very white or tinged blue. Spider venom is injected through a hollow fang. Spiders bite, they don't sting. Like most venoms, the substances injected by the brown spiders will digest tissue. People who have been bitten by a brown spider often feel nothing at first. But an aching sets in at the site after six to eight hours, as blood vessels are closed off by the poison and tissue begins to starve. A blister appears and there may also be flulike symptoms. The blister breaks, leaving a black area of dead or dying tissue. The bite may appear as a dark spot, with a white area surrounding it and a red ring around that - the so-called bull's-eye lesion. Fortunately, spiders are small and people are big, and fatalities are extremely rare in the US. More commonly, the bite of a brown spider results in an ugly black patch of dead tissue that rots and falls off after a few weeks, leaving a deep ulcer that takes many months to heal. If bitten, go to the emergency room. don't wait for symptoms to appear. A severe reaction may range from nausea to a high fever that can last a week. In most cases, analgesics (such as aspirin) are given for pain while doctors watch for systemic reactions. Usually nothing more is required. An antivenom is being tested. Gila Monsters There are two venomous lizards, the Gila monster and the Mexican beaded lizard. The Gila monster lives in the Sonoran Desert across southwestern Arizona and down into northwestern Mexico, as well as in the Chihuahuan Desert in northwestern Arizona, the southern tip of Nevada (around Las Vegas) and the southwestern corner of Utah (vicinity of St. George). They also live in a small area in eastern California. The Mexican beaded lizard occurs in Mexico only. The markings on these saurians are never quite the same, yet no one seems to mistake a Gila monster for anything else. They are usually black and pink (or coral) colored. The largest lizards in the US, they can reach 20 inches in length, and the largest specimens can weigh up to two pounds. The Mexican beaded lizard is a similar looking animal with a longer tail than the Gila monster. It can grow to three feet in length. Think about it. Most active in March, April, and May, Gila monsters are not easy to find. They don't crawl up and bite people. They are slow and torpid animals. Since it's virtually impossible to be bitten without picking the animal up, don't pick up any Gila monsters. Their delivery of venom depends on how long they can hang on and chew. If you can get their jaws pried open and take your hand out of the lizard's mouth, chances are that little venom will enter your system. Trying to shake the lizard off won't work well. Place it on the ground and pry its jaw open with a stick, knife, or other tool. Some people suggest holding a flame beneath its jaw or submerging it in water, or even squirting lighter fluid on its snout. This last technique presents us with the possibility of someone running in circles with a flaming lizard attached to his hand. The bite is reported to produce "instant and excruciating pain." Gila monster venom is similar to rattlesnake venom in its action. Because the venom contains fewer of the anticoagulant agents and digestive enzymes, tissue damage will be lessened or absent. Gila monster bites are rare. But the venom is highly toxic and there's no way to tell how much you received. Weakness, dizziness and shock could result. That may not be a reliable criterion, since some people grow weak and dizzy at the very thought of having a lizard attached to their hand. No human deaths resulting solely from Gila monster venom have been documented. No antivenom exists. The most important thing the docutor can do is remove the Gila monster's teeth, which break off in the wound and cause infection. A tetanus shot isn't a bad idea either. It's impossible to give this advice often enough: Don't apply ice or a tourniquet. Do remove the lizard. Do get to a hospital. If you do happen to die from a Gila monster bite, they will probably erect a statue on the spot. Excerpt from Men's Journal March 95 Article 37244 of rec.backcountry: From: "David" <email@example.com> Newsgroups: rec.backcountry References: <42aad888$1@darkstar> Subject: Re: [l/m 7/25/2001] Snakebite: Distilled Wisdom (11/28) XYZ Lines: 232 X-Priority: 3 X-MSMail-Priority: Normal X-Newsreader: Microsoft Outlook Express 6.00.2900.2180 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2900.2180 X-RFC2646: Format=Flowed; Original Message-ID: <W59re.3507$VK4.firstname.lastname@example.org> Date: Mon, 13 Jun 2005 05:47:34 GMT NNTP-Posting-Host: 126.96.36.199 X-Complaints-To: email@example.com X-Trace: newsread1.news.atl.earthlink.net 1118641654 188.8.131.52 (Sun, 12 Jun 2005 22:47:34 PDT) NNTP-Posting-Date: Sun, 12 Jun 2005 22:47:34 PDT Organization: EarthLink Inc. -- http://www.EarthLink.net Path: darkstar!news-hog.berkeley.edu!ucberkeley!newshub.sdsu.edu!elnk-nf2-pas!newsfeed.earthlink.net!stamper.news.pas.earthlink.net!stamper.news.atl.earthlink.net!newsread1.news.atl.earthlink.net.POSTED!bf6b25d7!not-for-mail Xref: darkstar rec.backcountry:37244 "Eugene Miya" firstname.lastname@example.org: "A number of field studies have shown that a Sawyer's Extractor (Sawyer's Products, Safety Harbor, Fla), which provides about one atmosphere of negative pressure, is effective in extracting venom from the bite site . . ." David email@example.com: The information above is outdated and dangerous. Read: Snakebite Suction Devices Don't Remove Venom: They Just Suck Sean P. Bush, MD Department of Emergency Medicine, Loma Linda University School of Medicine, Medical Center and Children's Hospital, Loma Linda, CA. Annals of Emergency Medicine. 2004;43:187-188. It was only a few decades ago that incision and suction were recommended snakebite first aid. However, concerns arose about injuries and infections caused when laypersons made incisions across fang marks and applied mouth suction. Meanwhile, several snakebite suction devices (eg, Cutter's Snakebite Kit, Venom Ex) were evaluated, and it was determined that they were neither safe nor effective.1 So, recommendations changed, and mechanical suction without incision was advocated instead.2-5 It seemed intuitive that suction alone would probably remove venom and should not cause harm. However, when the techniques were studied rigorously, quite the opposite was discovered. One of the most popular suction devices, the Sawyer Extractor pump (Sawyer Products, Safety Harbor, FL), operates by applying approximately 1 atm of negative pressure directly over a fang puncture wound (or wounds) without making incisions. The manufacturer instructs that the device be applied within 3 minutes of the snakebite and left in place for 30 to 60 minutes. For many years, most agreed (including the Wilderness Medical Society and the American Medical Association) that the Extractor might be beneficial and would probably cause no harm.2-5 Others suggested that it could exacerbate tissue damage, adding insult to injury after viper envenomation.6-9 In this issue of Annals, the Extractor's inefficacy has been further confirmed with a well-designed study and fully detailed manuscript.10 In their prospective experimental trial, a human model was used to test the amount of radioactively labeled mock venom that could be removed by an Extractor after subcutaneous injection with a 16-gauge hypodermic needle. The investigators measured radioactive count as an approximation of the amount of venom removed. The bottom line: the Extractor removed 0.04% to 2.0% of the envenomation load. The authors conclude that this is a clinically insignificant amount and that the Extractor is essentially useless.The main limitation of their study is that they could not use real venom. The study by Alberts et al10 corroborates other studies that have tested the efficacy and safety of the Extractor. Using a porcine model and real rattlesnake venom in a randomized, controlled trial, Bush et al11 measured swelling and local effects as outcome variables after application of an Extractor to artificially envenomated extremities. The conclusion of the study was that the Extractor did not reduce swelling, but resulted in further injury in some subjects. Specifically, circular lesions identical in size and shape to the Extractor suction cups developed where the devices had been applied. These lesions subsequently necrosed, sloughed, and resulted in tissue loss that prolonged healing by weeks. Similar injuries after Extractor use have been noted in human patients.1,12 In another study, Extractors were applied to 2 human patients immediately after rattlesnake envenomations, and the device was left in place until its cup filled with serosanguinous fluid 5 times, although the authors do not specify the volume(s) of fluid obtained. The concentration of venom was measured in the fluid removed using an enzyme-linked immunosorbent assay.13 There were no control subjects, and this study has only been published in abstract form. Ironically, this abstract is cited amongst the main supporting evidence for the Extractor.4,14 However, a closer review of the results reveals that the concentration of venom in the serosanguinous fluid removed was only about 1/10,000th the concentration of rattlesnake venom.Alberts et al10 similarly noted that although a relatively large volume of bloody fluid was pulled from the puncture site, it contained virtually no venom. Most interestingly, Alberts et al found that the amount of venom in the fluid that spontaneously oozed from the wound was greater than the amount of venom in the Extractor aspirate. It is possible in these 2 experiments that the fluid obtained came from superficial tissues, and that the strong suction exerted by the device collapses the distal portion of the fang tract where the venom is deposited, thereby reducing the amount of venom that would spontaneously ooze out. This suggests, like the study by Bush et al,11 that the Extractor might make the envenomation worse by paradoxically increasing the amount of venom left in the wound. Although each of these 3 studies was done independently of each other and using different methodology, they arrive at the same conclusion: the Extractor does not work, and it could make things worse. The only study that suggests the Extractor removes a clinically important amount of venom is an uncontrolled experiment using a rabbit model.15 Unfortunately, this study was only published as an abstract, and the methodology is not described in detail. Furthermore, its results are suspect for many reasons. Rabbits have a very thin subcutaneous layer, unlike humans (and pigs).16 Most snake envenomations are thought to occur in the subcutaneous layer.17 It is possible that in Bronstein et al's15 investigation the injected venom collected just under the rabbit's skin, where it was easily suctioned back out by the device. Because this inadequately documented single abstract reports a finding that is vastly different from all the other studies that follow, its conclusions are questionable and may be erroneous. If there was controversy before, the study by Alberts et al10 adds to the growing pile of evidence against the Extractor. This study should change our practice. We should stop recommending Extractors for pit viper bites, and the manufacturer should certainly stop advertising that they are recommended medically as the only acceptable first aid device for snakebites. Because it is becoming clear that this gadget does not work, future investigations should focus on other first aid techniques, such as pressure-immobilization or others yet to be discovered. Meanwhile, the best first aid for snakebite is a cell phone and a helicopter. R E F E R E N C E S 1. Hardy DL. A review of first aid measures for pitviper bite in North America with an appraisal of Extractor suction and stun gun electroshock. In: Campbell JA, Brodie ED Jr., eds. Biology of the Pitvipers. Tyler, TX: Selva Publishing; 1992:405-414. 2. Forgey WW, ed. Wilderness Medical Society Practice Guidelines for Wilderness Emergency Care. Merrillville, IN: ICS Books; 1995. 3. Forgey WW. More on snake-venom and insect-venom extractors [letter]. N Engl J Med. 1993;328:516. 4. Gold BS. Snake venom extractors: a valuable first aid tool [letter]. Vet Hum Toxicol. 1993;35:255. 5. Forgey W, Norris RL, Blackman J, et al. Viewpoints: response. J Wild Med. 1994;5:216-221. 6. Gellert GA. Snake-venom and insect-venom extractors: an unproved therapy [letter]. N Engl J Med. 1992;327:1322. 7. Gellert GA. More on snake-venom and insect-venom extractors [letter]. N Engl J Med. 1993;328:516-517. 8. Winkel KD, Hawdon GM, Levick N. Pressure immobilization for neurotoxic snake bites. Ann Emerg Med. 1999;34:294-295. 9. Warrell DA. Snake bite and snake venoms. Quart J Med. 1993;86:351-353. 10. Alberts MB, Shalit M, LoGalbo F. Suction for venomous snakebite: a study of "mock venom" extraction in a human model. Ann Emerg Med. 2004;43:181-186. 11. Bush SP, Hegewald K, Green SM, et al. Effects of a negative-pressure venom extraction device (Extractor) on local tissue injury after artificial rattlesnake envenomation in a porcine model. Wilderness Environ Med. 2000;11:180-188. 12. Bush SP, Hardy Sr DL. Immediate removal of Extractor is recommended [letter]. Ann Emerg Med. 2001;38:607-608. 13. Bronstein AC, Russell FE, Sullivan JB. Negative pressure suction in the field treatment of rattlesnake bite victims [abstract]. Vet Hum Toxicol. 1986;28:485. 14. Norris RL. A call for snakebite research. Wilderness Environ Med. 2000;11:149-151. 15. Bronstein AC, Russell FE, Sullivan JB, et al. Negative pressure suction in the field treatment of rattlesnake bite [abstract]. Vet Hum Toxicol. 1985;28:297. 16. Hobbs GD. Brown recluse spider envenomation: is hyperbaric oxygen the answer? Acad Emerg Med. 1997;4:165-166. 17. Gold BS, Barish RA, Dart RC, et al. Resolution of compartment syndrome after rattlesnake envenomation utilizing non-invasive measures. J Emerg Med. 2003;24:285-288. Source: http://www.med.unc.edu/emergmed/teachme/Journal%20club/journal%20club%20June%202004,%20snake%20bite/snake%20bite%20suck%20ANNALS.pdf See, also: Annals of Emergency Medicine Volume 43, Issue 2 , February 2004, Pages 181-186 Suction for venomous snakebite*1 A study of "mock venom" extraction in a human model Michael B. Alberts MD, , a, Marc Shalit MDa and Fred LoGalbo MDb a Department of Emergency Medicine, University Medical Center, University of California, San Francisco, Fresno b Department of Radiology, Community Medical Center of Central California, Fresno An abstract of this paper is printed below. The full text is available at: http://www.med.unc.edu/emergmed/teachme/Journal%20club/journal%20club%20June%202004,%20snake%20bite/venom%20extractor%20annals.pdf Study objective We determine the percentage of mock venom recovered by a suction device (Sawyer Extractor pump) in a simulated snakebite in human volunteers. Methods A mock venom (1 mL normal saline solution, 5.0 mg albumin, 2.5 mg aggregated albumin) radioactively labeled with 1 mCi of technetium was injected with a curved 16-gauge hypodermic needle 1 cm into the right lateral lower leg of 8 supine male volunteers aged 28 to 51 years. The Sawyer Extractor pump was applied after a 3-minute delay, and the blood removed by suction was collected after an additional 15 minutes. A 1991 Siemens Diacam was used to take measurements of the radioactive counts extracted and those remaining in the leg and body. Results The "envenomation load," as measured by mean radioactivity in the leg after injection, was 89,895 counts/min. The mean radioactivity found in the blood extracted in the 15 minutes of suction was 38.5 counts/min (95% confidence interval [CI] ?33 to 110 counts/min), representing 0.04% of the envenomation load. The postextraction leg count was less than the envenomation load by 1,832 counts/min (95% CI ?3,863 to 200 counts/min), representing a 2.0% decrease in the total body venom load. Conclusion The Sawyer Extractor pump removed bloody fluid from our simulated snakebite wounds but removed virtually no mock venom, which suggests that suction is unlikely to be an effective treatment for reducing the total body venom burden after a venomous snakebite. -- Looking for an H-912 (container).
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