Newsgroups: rec.backcountry
From: eugene@amelia.nas.nasa.gov (Eugene N. Miya)
Subject: [l/m 9/2/92] Snake bite: Distilled Wisdom (11/28) XYZ
Organization: NAS Program, NASA Ames Research Center, Moffett Field, CA
Date: Mon, 11 Jan 93 12:20:18 GMT
Message-ID:
Reply-To: hall@vice.ico.tek.com (Hal Lillywhite)
Lines: 881
Panel 11
[These lines may not correspond in your news reader.]
TABLE OF CONTENTS
Summary . . . . . . . . . . . . . . . . . . Line 25
Acknowledgments and References . . . . . . Line 74
Various Snakes and their Effects . . . . . Line 193
Venoms . . . . . . . . . . . . . . . . . . Line 237
Four Special Cases . . . . . . . . . . . . Line 276
Identification . . . . . . . . . . . . . . Line 344
The “Three Nasties” . . . . . . . . . . . . Line 425
Eastern Diamondback . . . . . . . . . . Line 478
Western Diamondback . . . . . . . . . . Line 526
Mojave . . . . . . . . . . . . . . . . . Line 552
Prevention . . . . . . . . . . . . . . . . Line 621
Treatment . . . . . . . . . . . . . . . . . Line 690
SUMMARY:
Poisonous snake bite is a potentially serious accident. It can
lead to severe pain or other problems, occasionally even death.
However in North America it is not nearly as dangerous as most
believe. These snakes seldom bite humans and even when they do
such 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 comming, don’t reach into places they
might hide, be careful turning over rocks, boards etc. in snake
country. Leave snakes alone unless you are sure they are safe
(there is no simple rule to identify which are poisonous). This
also applies to dead snakes and detached heads – reflex bites are
just as dangerous as bites by a live snake.
If someone is bitten:
Clean and disinfect the wound.
Transport to a hospital as quickly as reasonably possible.
Try to keep the patient quiet and resting. If necessary a
victim alone must walk to reach treatment but this should be
avoided if possible.
Immobilize the area much as for a fracture. Use constricting
bands above and below the site but be certain they do not
interfere with blood circulation, they are only to slow down
the movement of lymphatic fluids just under the skin.
Alternatively, wrap entire area snugly with a cloth, elastic
bandage, etc again being careful not to interfere with blood
circulation.
As best you can, identify the snake to aid in determining the
proper treatment. If you can do so safely, kill the snake and
take it with you to the hospital for definite identification.
(But don’t kill snakes which haven’t bitten anybody.)
*DO NOT* cut into the wound area unless you are medically
trained to do so. You will probably do more damage than the
snake did. If you have a good syringe style suction device
and the snake is a pit viper, you may attempt to suck venom
out through the wound it went into, but do not let this delay
evacuation to a hospital.
[End of Summary]
ACKNOWLEDGEMENTS AND REFERENCES
At the outset I would like to thank the following for their helpful
comments and suggestions:
loosemore-sandra@CS.YALE.EDU (Sandra Loosemore)
blazekm@a.cs.okstate.edu
pholland@iastate.edu (Paul Hollander)
KLEINSCHMIDT@MCCLB0.MED.NYU.EDU (Jochen)
A special thanks to:
CWA@NAUVAX.UCC.NAU.EDU (Curt Anderson) for providing information I
was not able to find in the library here.
ed@titipu.meta.COM (Edward Reid) who put me into contact with Paul
Moler, a professional herpologist with the Florida Dept. of Game
and Freshwater Fish.
And of course a big thanks to Dr. Moler who was very helpful in
correcting some errors and providing information.
References – as long as this posting is, it only scratches the
surface. The following sources will provide more information:
_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. This book, published by the
Mountaineers in Seattle, is probably the standard reference for
backcountry medicine.
_A Field Guide to Western Reptiles and Amphibians_, Robert C.
Stebbins, Houghton Mifflin, 1966. A good guide to snakes (and other
reptiles etc.) including descriptions, color illustrations and maps
of their ranges. Part of the Peterson Field Guide Series, sponsored
by the Audubon Society and National Wildlife Federation. 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
which I have not seen. This book does not provide as much
identification information as does Stebbins (but it does include
range maps). It does provide a lot of interesting information about
all sorts of topics from the snake life cycle to collections of
folklore and misinformation.
I have not actually seen the following although others have
recommended them:
_The Audubon Society Field Guide to North American Reptiles and
Amphibians_
_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.
Russell, Findlay E. 1983. _Snake Venom Poisoning_. Scholium International,
Great Neck, NY. (reprint with corrections of the 1980 edition.)
INTRODUCTION:
Snakebite is always a hot topic. In what follows I 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, movies etc. have greatly exaggerated both the probability
of snakebite and the likely outcome should it happen. We are much
less likely to get bitten than many would have us believe. Further-
more 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, sometimes even panic. Aside from its adverse effect on the
enjoyment of life, this fear and panic can lead to:
Improper treatment of those few cases which need treatment for
envenomation
Dangerous overtreatment for bites in which envenomation does not
occur
Worsening of outcome of snakebites due to panic, and
Unnecessary and dangerous treatment of bites by non-poisonous
snakes.
With a couple of exceptions listed below, snakebite in the U.S.
should be treated conservatively. Even on those exceptions there is
no need to jump in with knives tournequets etc. to try to suck out
the venom (particularly by mouth). However victims should be given
appropriate treatment and rapidly evacuated to medical facilities.
“About no other medical subject has so much been written when
so little has been known!
“Poisonous snake bites 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 snake bites 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 (possibly offset by the larger snake having learned to
“ration” its venom while a younger animal is more likely to inject
the full load). However in North America we do not have the really
nasty varieties 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 in some parts of the world.
THE VARIOUS SNAKES AND THEIR EFFECTS:
According to MFM poisonous snakes in the US all belong to one of
two families:
Crotalids (pit vipers):
copperhead
water moccasin or cottonmouth
various species of rattlesnake
Elapids: only the coral snake (eastern and western versions)
lives in the U.S.
Crotalids have the most efficient injection mechanism of any snake,
about as good as a hypodermic syringe and needle. They are equipped
with relatively long hollow fangs backed up by a system of injecting
venom through those fangs. This gives them the ability to inject large
volumes of venom quickly. Crotalid fangs can fold back into the mouth
so lack of visible fangs does not necessarily mean an unarmed snake.
Most crotalids have venom less toxic than that of coral snakes.
Crotalids, however are more dangerous 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, a much less efficient
injection mechanism. Generally they chew to get the venom into the
victim. The size of coral snakes also limits them to biting fingers
or loose folds of skin. These snakes belong to the same family as
some of the world’s nastiest critters: black mamba, death adder and
cobra. However the American coral snakes is about as mild as a
poisonous snake can be. It is not aggressive. – Children have
reportedly played with them for hours without being bitten. (No
record exists of how many parental heart attacks this has caused.)
The venom is relatively potent, however, and treatment should be given
for bites which do occur. Coral snake bites make up less than 2% of
all U.S. snake bites. There are no known fatalities from coral snake
bites since the development of the _Micrurus fulvius_ antivenom.
The western coral snake is even less dangerous. It is smaller yet
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
other coral snake bites.
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.
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.
However symptoms can appear later. Neurotoxins produce much less
local reaction than do hemolytic toxins. However 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 most North
American snakes. However respiratory distress without actual arrest
is likely 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. However in
general the pit vipers have a higher fraction of hemolytic toxin
while 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. Furthermore the typical snake mouth is no
cleaner than a human’s – they tend to have a lot of microbial
contamination. It is common for a snake to bite without injecting
venom, especially in larger animals. However the microbial
contaminants will always be present and should always be treated.
(Such contamination seems to be much less of a problem in bites by
non-venomous snakes, probably because they do not penetrate deeply.)
FOUR SPECIAL CASES:
Four varieties deserve special mention: the copperhead because a
single bite is not very dangerous, and the diamondback (eastern and
western) and Mojave rattlesnakes because they are dangerous:
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. I would 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.
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 claims it is not particularly
aggressive and quotes some numbers which indicate that it is unlikely
to lead in killing people. I am inclined to believe Dr. Moler who
lives and works in the habitat of the eastern diamondback. I
suspect this snake’s impressive size and defense displays have given
it an exaggerated reputation. Its western cousin is almost
certainly more aggressive and at least as well equipped to ruin
your day.
The Mojave rattler is quite dangerous in spite of its size. This
little rascal (little compared to the diamondbacks anyway) is armed
with a very potent venom, high in neurotoxins. Initial reaction is
usually mild with severe symptoms comming 12 to 16 hours after the
bite. The early symptoms can easily fool you into believing there
is no problem. By the time severe symptoms appear the best time for
treatment will have passed. (This one 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.)
Bites from either diamondback or the Mojave rattler should be
*aggressively* treated. This does not mean cutting unless you meet
all the conditions for it described below. However do treat such
bites with any appropriate suction device you have, try to immobilize
the venom and the affected area, and 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. I can’t discuss them here. They are generally confined to
warmer climates in places such as Australia, Africa, the Indian
Subcontinent and Southeast Asia. (There are some exceptions such as
the European viper which ranges up to the Arctic Circle but is not
as dangerous as some of the snakes inhabiting warmer climates). If
you plan to engage in wilderness activities in these areas you might
look up something about the snakes there before you go, or post a
request and maybe somebody familiar with the area of interest can
answer. Many of these areas are inhabited by snakes *much* more
dangerous than those native to the North America. 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).
IDENTIFICATION:
*********************************************************************
* Rule One: If in doubt about whether a snake is poisonous or not, *
* >leave it alone<. There is no reliable rule to distinguish which *
* snakes are poisonous and which are not. Characteristics vary *
* greatly depending on locale and occasional individuals have *
* atypical coloration or pattern. *
*********************************************************************
It is useful to be able to identify the poisonous varieties of
snake. 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 and
brightly colored with small heads. They can be distinguished from
the nonvenomous king snake and other harmless species by the presence
of adjacent red and yellow bands while king snakes 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!
Pit vipers are a bit more difficult. Of course the presence of
rattles tells you that you are dealing with a poisonous 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
they may be folded back in the mouth and difficult to detect, or
they may be broken off. The easiest indicator (but one which needs
practice, maybe in a zoo) is the characteristic heavy body and
triangular head of the pit viper. While some non-poisonous snakes
also have these characteristics it is better to treat a snake with
caution unless you absolutely know it is safe.
You may also look for the pit after which the pit viper is named.
This will be between the eye and nostril, one on each side of the
head (of course on the other hand you may not want to look that
closely.) The other sure indicator, although not terribly useful
for obvious reasons, 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. This last information
is probably only useful to identify a dead snake, I certainly
wouldn't want to pick up a live one to look at its underscales, at
least until I know it is not poisonous.
Some older references suggest checking the pupils of the snake's
eyes for identification. Pit vipers will have vertical slit pupils.
If it has round pupils it is not a pit viper. Perhaps, but I'm not
anxious to get that close to a snake if I think it might be
venomous.
One good indicator of the type of snake is the location. Snakes
don't wander far from home and tend to have a limited range and not
survive outside the conditions they prefer. Except in the rare case
of an escaped 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. It is
good to be familiar with what the dangerous snakes look like, but be
sure you can be accurate or treat all snakes with caution. See the
references listed above for pictures and other help in identifica-
tion. If you are concerned about venomous snakes, get a book on
herpetology and study it. Visit zoos, talk with specialists etc.
I assure you that you will not become an expert by reading usenet.
Again, the best rule is, if there is any chance that the snake is
poisonous, leave it 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!
THE "THREE NASTIES:"
These three species all have the venom to make you pay *dearly*
should you upset them. However different sources give different
assessments of the disposition of the eastern diamondback and 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 all three 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. Their bites are not sure death but are more
likely to cause death than other North American venomous snakes.
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 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).
If you can safely kill a snake which has bitten someone, do so. You
can then measure the length and take the snake with you to the hospital
for expert identification. Be careful to avoid reflex bites – either
from an intact dead snake or from a detached head. I do not advocate
killing a snake unless it has actually bitten a person.
You will notice some discrepancies in the following descriptions.
While all authorities agree that the eastern diamondback is our
largest rattler, the guidebooks list a greater length for the
western version. I attribute this to the fact that the descriptions
come from different books. Probably one author is more conservative
than the other. Either diamondback can be impressive – they are
known to swallow cottontail rabbits whole! (And there are less
reliable reports that they do the same with jackrabbits.)
Different authors also do not agree on which is the most dangerous,
some claiming this "honor" for the eastern diamondback, some for the
western version. The eastern version is larger and has more venom
but its western cousin has a more potent venom. In my opinion 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. I'm not sure it matters much, I would not
want to be bitten by any of the three. My (partially educated)
opinion is that the western diamondback is the most dangerous since
it is probably the most likely to bite a person. Next would be the
Mojave, less likely to bite but likely to administer a *nasty* dose
of venom. The eastern diamondback would be third, probably no more
likely to bite than a Mojave and a less severe (but still quite
dangerous) venom load.
EASTERN DIAMONDBACK (Crotalus adamanteus)
(Thanks to Curt for emailing this since I couldn't find the books
referenced in our library.)
According to Conant's Reptiles & Amphibians of Eastern/Central U.S.,
"33-72"; record 96"(!). 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 Audubon's herp guide (not very good for identification of
unknowns, but has good info and pictures):
"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, Mojave and western diamondback, 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 this 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. Similar problems
exist – that is for all except the Mojave lack of local reaction
indicates no envenomation. Again, unless you can positively
identify the snake as not a Mojave, assume that any bite was
administered by the Mojave if in its range.
Mojave venom can be up to 20 times the as potent as diamondback venom
although 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) pp55-56
_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. As far as I know, nobody has
yet found any differences between it and its more widely distributed
cousins except that its venom is very similar to the diamondback
venom. This of course makes it less dangerous than the standard
version. 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 diamondback 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.
Obviously all Mojave (or suspected Mojave) bites should be treated
for the worst case.
PREVENTION:
Obviously the best prevention is to avoid getting bitten. This is
facilitated by the fact 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. The basic rule is to be sure the
snake knows you are coming. Walk heavily, they probably 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 of the more common activities leading to snakebite.
Going barefoot not only exposes you but 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
distinguishing between clothing and you. Venom injected into a
fold of your clothing won't hurt you much.
Remember that snakes like to hide under rocks, logs, brush etc. 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, or even walking by them. They might well perceive your
actions as aggressive and defend themselves. This is probably the
most dangerous situation since there may be more than one snake in
the same place and, taken by surprise, they will strike without
warning. Furthermore they will be more likely to bite your
unprotected hand, not a leg or foot protected by clothing.
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 near
ledges etc. Remember, the mice and rats which inhabit many cliff
areas mean food to a snake and so attract them.
It is also a good idea to protect yourself while sleeping. Snakes
won't come looking to bite you, but when the temperature starts
to drop they often do look for a warm place to spend the night.
That sleeping bag with you inside can be very attractive. Use
insect netting or something else to keep them out (unless you
relish the thought of waking up to find a snake in bed with you).
There is a bit of controversy about if they will actually crawl into
bed with you, but I would want to take precautions. Also check the
sleeping bag before you get in to be sure it isn't already
occupied. The same goes for your boots in the morning.
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 also applies to detached heads of dead snakes.
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, snake bite 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. It is better if you can safely take it with you to
the hospital to be sure of getting the right anti-venom. However
do not risk more bites to do so. Remember the first rule of rescue:
Do not create any more victims or risk further injuring the current
victim.
Treat for microbial infection. Bacteria which cause tetanus and gas
gangrene have been isolated from the mouths of poisonous snakes.
Cleanse the wound and if possible disinfect with Betadyne or other
effective antiseptic. Cleansing and disinfecting the wound is the
single most effective treatment you can give in the field. The
victim should also be sure his tetanus vaccine is up to date.
Definitive treatment requires a physician who will administer anti-
venom as well as other treatment. Most antivenom is made with horse
serum so try to find out if the patient has any allergy to it and if
so be sure the doctor is informed of that fact. Keep the patient as
quiet as possible and evacuate quickly to medical facilities.
A word about the Mojave: Most of the snakes of this species have a
venom high in neurotoxin as described above. This is particularly
difficult to treat, both in the field and in a medical facility.
The standard antivenom is less effective against it than against
venoms with a higher percentage of hemolytic toxins. It is
especially important to start treatment quickly for a Mojave bite.
The bitten limb must be immobilized and spread of the venom slowed
as much as possible. This is one case where it would be worth an
extra effort to remove the venom if the conditions below can be met.
Also be extra diligent to in transporting the victim quickly to a
hospital. Be prepared to provide breathing assistance.
A victim alone should try to evacuate himself to medical facilities,
even if this includes walking. Obviously he should do no more
exercise than absolutely necessary.
If the victim is accompanied by only one other person that person
should do as much treatment as can be done quickly, then go for help.
Larger groups should send someone for help while others stay to
provide as much treatment as they can, or start to evacuate the patient
if possible. The object is to get the victim to a medical facility
quickly with as little rough handling or movement on his part as
possible. Helicopter evacuation is preferred but even having an
ambulance at the trailhead is a great help.
Try to slow the spread of the venom. Use constricting bands above
and below the site of the bite. These should *not* be tight enough
to cut off circulation, all you want to do is slow down the movement
of the fluids under the skin. Keep watching these bands, they should
not be on a swollen area and you may have to move them as swelling
increases. To re-iterate: *Do*not*cut*off*circulation*.
A more recent development for immobilizing the venom is to wrap the
area snugly with fabric and immobilize the limb with a splint. Any
type of fabric, including elastic bandages, works well. Just be
sure it is not tight enough to cut off blood circulation and watch
for swelling which might make it too tight.
The bitten limb should be immobilized, especially if bitten by an
elapid such as a coral snake. Treat it like a fracture.
You will not be able to remove very much of the venom, almost none
in an elapid bite where the chewing will have dispersed it. However,
you should try if *all* of the following criteria are met:
1. You can start venom removal within 10 minutes (thereafter it
tends to be so dispersed that you will not likely be very
effective)
2. You have appropriate suction devices to remove it. This means a
syringe style suction device, the rubber suction cups often sold in
"snake-bite kits" do not develop enough suction to do the job. It
is not necessary to cut the wound to suck out venom, it went in
through the fang marks and can come out the same way. In my opinion
you should not try to suck it out with your mouth. That is not likely
to be effective, risks venom getting into your blood via an open sore,
and most importantly is likely to further contaminate the wound. If
you lack an appropriate suction device, forget it.
3. The bite was inflicted by a pit viper.
If you do try to remove the venom, place the suction device over the
fang marks. They may not always be obvious if the snake has bitten
hard enough to leave marks from other teeth also. Be aware that you
are not going to get out much of the venom. Removal of 5 to 15%
would be about all you can expect. The sooner after the bite you
start the more effective you will be, the venom disperses quickly.
There is some controversy over the idea of cutting into the flesh
around the fang marks. While this can facilitate removal of venom
it is also very dangerous. Unless you really know what you are
doing you may do more damage than the snake did. Muscles, nerves,
and blood vessels may all be in the area and you can damage them,
sometimes permanently. Most classes I have attended do not
recommend cutting. MFM recommends it under certain conditions,
namely:
1. The "surgeon" knows enough to avoid cutting anything vital. In
my mind this eliminates most of us, including myself, from doing
this cutting. The cuts need to be quite deep, about an eighth to a
quarter of an inch, and I don't think most of us remember enough
anatomy to do that safely, especially during the tense times which
accompany a snake bite.
2. The culprit is positively identified as a pit viper. (Antivenom
is the only effective treatment for elapid bites, including the
coral snake.)
3. The victim is 3 hours or more from the nearest medical facility
and incision and suction will not delay evacuation.
Keep in mind that MFM is aimed at a readership which includes some
highly trained medical people, physicians etc. It may make sense
for them to perform some procedures which most of us should not even
think about attempting. You will do no damage with an appropriate
attempt to suck venom out of the same wound it went in. However you
can do a *lot* of damage when you start cutting. Leave the surgery
to those trained and licensed to do it.
(MFM mentions cold therapy only to *strongly* advise against its use.
It is *not* effective and, particularly in the case of a pit viper
bite, will impede recovery. Cold will restrict circulation already
compromised by the damage to blood vessels. Furthermore, the body's
principle detoxifying mechanism appears to be the action of
antibodies against the venom. Lowering of the temperature retards
access of antibodies to the toxins. Cold therapy apparently was
proposed on the assumption that the venom is an emzyme. In fact
most are peptides which cooling does not inactivate.)
How about a "snake-bite kit?" Obviously you want to be prepared for
emergencies which are likely to happen but I don't think that
necessarily means buying a kit and carrying it all the time. Except
for a suction device you should already be carrying everything you
need in your standard first aid kit. Snakebite is so rare that I
don't think I would even bother with a suction device unless a bite
by one of the "three nasties" is a reasonable probability. Items
which ought to be in your first aid kit and are useful in case of
snake bite are:
1. A good antiseptic (eg. Betadyne) to cleanse the bite.
2. Elastic bandage or gauze ("cling") to use in making constricting
bands or wrapping the area to immobilize the venom.
3. Splinting materials to immobilize the limb bitten.
(Written by Hal Lillywhite. Last update: 2 September 1992)
TABLE OF CONTENTS of this chain:
11/ Snake bite
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/ Words from Foreman and Hayduke
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 and advice
9/ Water Filter wisdom
10/ Words from Rachel Carson
END.
