and Head Structure
are highly toxic secretions produced in special oral glands . Because
these oral glands are related to the salivary glands of other vertebrates,
venom can be considered a modified saliva.
chemistry of snake venoms is complicated . Venoms are at least 90%
protein (by dry weight), and most of the proteins in venoms are enzymes
. About 25 different enzymes have been isolated from snake venoms,
12 of which occur in all venoms .
all toxic chemical compounds in snake venoms are enzymes . Polypeptide
toxins, glycoproteins, and low-molecular-weight compounds are also
present in mambas and colubrids . The roles of the other components
of venom are largely unknown .
general, snake venom will fall into one of the categories listed below.
blood from clotting.
effects that target heart function. Some depolarize cardiac
muscles and alter heart contraction, causing heart failure .
mostly with elapids ad vipers
white blood cells.
|| all venomous
red blood cells.
vipers and pitvipers
capillary walls causing bleeding. (hemorrhages near and distant
from the bite)
pitvipers, and the king cobra
transmission of nerve impulses to muscles, especially those
associated with the diaphragm and breathing
vipers, tropical rattlesnakes, and some North American Mojave
cells and tissue at the bite site, causing local pain and swelling
mostly in viper and pitviper
blood and foster clot formation throughout the circulatory system
enhance one of the body’s natural responses to injury
(dilation and increased permeabilty of blood vessels, stimulation
of pain receptors, and contraction of some smooth muscles),
thereby enhancing diffusion of venom in the bloodstream, increasing
bleeding, and thwarting the ability to flee .
disrupt nerve-impulse transmission, usually causing heart or
and colubrids :
the breakdown of structural components of tissues
reactions that break mucopolysaccharide links in connective
tissues, thereby enhancing diffusion of venom
reactions that disrupt protein peptide bonds in tissues, causing
blood-vessel wall damage and hemorrhaging and muscle-fiber deterioration
reactions that harm musculature and nerves
all venomous species
pitvipers, a few elapids (but rare)
growth factor (an enzyme)
the growth of nerve cells
enzymes : ribonucleases, deoxyribonucleases, nucleotidases,
amino acid oxidases, lactate dehydrogenases, acidic and basic
normal cellular function, causing death of the affected cells
and elapids (occurrences vary)
normal immune response of tissues through anticomplementary
Dendroaspis, Notechis, Bungarus
normal transmission of nerve impulses and other types of signalling
Crotalus, Trimeresurus, Agkistrodon, Crotalus
normal transmission of nerve impulses, causing heart and respiratory
Components (Organic and Ignorganic)
: Neutral sugars, Amino sugars, Sialic acid .
Lipids : Cholesterol, Monoglycerides, Diglycerides,
ions (which activate and deactivate enzymes)
: Calcium, Chlorine, Copper, Iron, Magnesium, Manganese, Nickel,
Phosphate, Potassium, Sodium, Sulfate, Zinc .
Microcomponents : Bismuth, Gold, Molybdnum, Palladium, Platinum,
Selenium, Silver . Water
composition can vary among individuals of the same species , and even
in the same litter , but variation is greater among geographically
Venom toxicity may also vary over time in the same individual . Generally
speaking , the venom of newborn and small juvenile snakes appears
to be more potent than that adults of the same species . Also , a
bite from a snake that has not fed recently , such as one that has
just emerged from hibernation , is more dangerous than that of one
that has recently fed , because it has more venom to inject . Venom
glands must replace venom lost with each strike-bite , and full replacement
takes time .
venom potency is typically determined by conducting an LD50 test.
LD stands for "Lethal Dose". LD50 is the amount of a material,
given all at once, which causes the death of 50% (one half) of a group
of test animals. The LD50 is one way to measure the short-term poisoning
potential (acute toxicity) of a material.
LD50 is usually expressed as the mass of substance administered per
unit mass of test subject, such as grams of substance per kilogram
of body mass. Stating it this way allows the relative toxicity of
different substances to be compared, and normalizes for the variation
in the size of the animals exposed (although toxicity does not always
scale simply with body mass). Typically, the LD50 of a substance is
given in milligrams per kilogram of body weight.
- Venom is injected under the skin.
- Venom is injected into a muscle.
Intravenous - Venom
is injected directly into a vein.
Intraperitoneal - Venom
is injected into the abdominal cavity.
Average Venom Yield
- Typical amount of (dry) venom that is obtained through "milking."
most commonly tested methods are subcutaneous
and intravenous injections of mice. Subcutaneous
is the most applicable to actual bites.
The LD50 test was created by J.W. Trevan in 1927 but is now
being phased out in favor of the Fixed
Copperhead (Agkistrodon contortrix mokasen)
Copperhead (Agkistrodon contortrix contortrix)
Species (Agkistrodon piscivorus)
(Agkistrodon piscivorus piscivorus)
(Agkistrodon piscivorus conanti)
(Agkistrodon piscivorus leucostoma)
Pygmy rattlesnake (Sistrurus miliarius
rattlesnake (Sistrurus miliarius barbouri)
rattlesnake (Sistrurus miliarius streckeri)
Canebrake rattlesnake (Crotalus horridus
rattlesnake (Crotalus adamanteus)
(Micrurus fulvius fulvius)
2503 Phoenix Drive
Tuscaloosa, AL 35405
the victim has collapsed or is not breathing, call 911.
Phone: (205) 345-0609
To Do If Bitten by a Venomous Snake
calm and call for help.
movement as much as possible and try to keep the wound below the
level of your heart. This will reduce the spread of venom.
off any jewelry or tight clothing near the bite before swelling
to remember what the snake looked like: its color, shape and markings.
This will help with your treatment.
the bite with a clean, dry bandage.
To Do If Bitten by a Snake in the Elapid Family
is the standard worldwide accepted first-aid treatment for bites by
elapid snakes such as cobras, mambas, coral
snakes and many Australian species.
bite to bleed freely 30 secs.
Use Sawyer Extractor (see below) for 15 secs to 1 minute over both
Cleanse and/or disinfect bite area throughly if possible
Apply hard direct pressure over bite using a 4 x 4 gauze pad folded
in half x 2
gauze pad in Betadine(tm) solution if available if not allergic
gauze pad tightly in place with adhesive tape
Overwrap dressing above and below bite area with ACE bandage
ACE (elastic) bandage as tight as one would for a sprain. Not too
Check for pulses above and below elastic wrap; if absent it is too
Immobilize bitten extremity, use splinting if available
If possible, try and keep bitten extremity below heart level or
in a gravity dependent position
Go to nearest hospital or medical facility as soon as possible
What NOT To
Do If Bitten by a Venomous Snake
NOT physically exert yourself beyond what is necessary
to get to a hospital
so will increase blood circulation, speeding the spread of
the venom beyond the area of the bite.
NOT take any kind of medication.
of any kind, including aspirin and vitamins, may cause unexpected
reactions with the venom. Also, many medications, such as
aspirin and other pain-killers, thin the blood and speed up
NOT eat or drink anything unless advised by medical
will facilitate a more accurate diagnosis at the hospital.
Of course, common sense should tell you that if you are out
in the middle of nowhere fluids will be necessary to avoid
NOT drink alcohol.
thins the blood, impairs judgment, overworks the kidneys,
and stresses the entire body.
NOT cut the place that has been bitten or try to
suck the venom out of the snakebite.
(i.e. cutting yourself open) is highly dangerous. An incision
that is too deep or misguided could sever nerves (causing
permanent paralysis in appendages) or cause massive bleeding.
Oral suction or the use of another suction device (as in pellet-shaped
snake bite kits) provides inadequate suction to extract venom.
In fact, strenuous oral suction can prove physically exhausting
and stressful, thus actually worsening the effects of the
bite. Evidence suggests that the application of a product
Extractor does NOT provide any benefits, and may actually
cause worse necrosis at the site of the bite.
NOT apply a constrictive tourniquet, or try to stop
the blood flow to or from the snakebite.
of any kind, even shoes or watches, may stop adequate blood
flow. Even the tissues around a snake bite require oxygen!
While the proper application of a tourniquet will not stop
blood flow, in such a stressful situation it is difficult
to apply and monitor a tourniquet. As the area around the
wound swells, the tourniquet would require almost constant
adjustments. In short, tourniquet are too complicated, too
dangerous, and don't work anyway.
NOT apply hot or cold packs, or ice.
may cause blood to flow into the snake bite area, thereby
causing the venom to spread more rapidly. On the other hand,
cold may reduce the diffusion of the venom too much, thereby
causing greater localized tissue damage.
NOT apply electric shock of any kind.
show this does NOT retard or reverse the spread of venom.
NOT kill or capture the offending snake to bring
with you to the hospital. You may put yourself at risk for
a second bite in doing so.
for pit viper bites is the same for all species so identification
is rarely necessary. Emergency room personnel will know from
the type of bite (punctured versus chewed tissue) whether
the attacker was a pit viper or coral snake.
of Snakebite Envenomation
fang marks (but may leave one or three puncture marks)
- is swelling or puffiness of parts of the body. It is caused
by water that gets trapped in the tissues of your body.
and also swelling in lymph nodes near the bite injury
or tingling around the mouth, tongue, scalp, feet, or the bite
pulse (changes in heart rate or rhythm)
- usually caused by blunt impact, in which the capillaries are
damaged, allowing blood to seep into the surrounding tissue
fasciculation - involuntary contraction of the muscle fibers
innervated by a motor unit
(oral) - tingling
metallic rubbery, or minty taste in the mouth
fang marks (but may leave one or three puncture marks)
- it is caused by weakness of the muscle responsible for raising
the eyelid, damage to the nerves which control those muscles,
or laxity of the skin of the upper eyelids.
(often numb at bite site)
- or double vision, is the perception of two images from a single
object. The images may be horizontal, vertical, or diagonal.
- a medical term defined as difficulty swallowing.
- excessive sweating commonly associated with shock and other
medical emergency conditions
- Decreased response of the deep tendon reflexes, usually resulting
from injury to the central nervous system or metabolic disease
depression - depression of respiration (breathing) that results
in the reduced availability of oxygen to vital organs
Scale for Severity of Snake Bites
or abrasions; some pain or tenderness at the bite
care, no antivenin
edema at the bite; perioral paresthesias may be present.
is necessary, it may reqiure about five vials
erythema, edema beyond the area adjacent to the bite; often,
systemic manifestations and mild coagulopathy
of five to 15 vials of antivenin may be necessary
pain and swelling of entire extremity, often with severe systemic
signs and symptoms;coagulopathy
at least 15 to 20 vials of antivenin
abnormal signs and symptoms; severe coagulopathy
at least 25 vials of antivenin
There are many, many variables that may affect the behavior of a snake
bite, such as:
Species (and even geographic location) of snake involved
Size of snake
Amount of venom injected
Size and overall health of bite victim
Location and depth of bite
Physiology of bite victim
Reaction of bite victim: panics, remains calm, delays trip to hospital,
If no symptoms appear within 8 to 12 hours, it is possible that no
venom was injected; this is called a dry
bite. At least 25%, perhaps up to 50%, of bites are
The severity of symptoms will depend on the type of snake that bit
you, how much poison was injected with the bite, and your personal
If poison is injected, about 35% of bites are mild envenomations,
25% are moderate, and 10% to 15% are severe. It is important to remember
that a snake only injects part of its venom with each bite, so it
is still a dangerous threat after the first strike. A young (immature)
snake is more likely to inject all its venom with its first strike
than an older snake. For this reason, a bite from a young snake can
be serious. A dead snake can have a bite reflex up to an hour after
death, so it must be considered dangerous as well. Even if no symptoms
appear within 8 hours, continue to watch for symptoms for up to 24
in general, come in two varieties:
(Crotalidae Polyvalent Immune Fab)
atrox, * Crotalus adamanteus, * Crotalus scutulatus, * Agkistrodon
piscivorus, Crotalus horridus, Crotalus viridis helleri, Crotalus
molossus molossus, Agkistrodon contortrix, Sistrurus miliarius
adamanteus, * Crotalus atrox, * Crotalus durissus terrificus,
* Bothrops atrox, Crotalus sp., Sistrurus sp., Agkistrodon contortrix,
Agkistrodon piscivorus, Agkistrodon halys, Bothrops sp., Crotalus
durissus, Agkistrodon bilineatus, Lachesis mutus
(Micrurus Fulvius) North American Coral Snake
fulvius fulvius, * Micrurus fulvius tenere
Species identified by an asterisk (*) indicate venoms used in the actual
production of the antivenom.
The production of antivenom involves hyperimmunizing ungulates (sheep
or horses) by injecting them over time with increasing quantities of
snake venom. Blood is then drawn and fractionated to refine and concentrate
the serum globulins. Add a couple of preservatives, such as Phenol and
thimerosal, some distiled water, and you have an antivenom. The antibodies
produced by the ungulates to combat the toxins in the venom now become
the active ingredients in the antivenom.
Antivenom should only be administered by trained professionals for very
severe snake bites. Some people have a severe allergy to antivenom (especially
those derived from horses) and a skin test is usually standard procedure.
Without using caution, the antivenom itself could potentially send someone
into life-threatening anaphylaxis! Depending upon the severity of the
bite, treatment may require 4 to 18 vials or more. Most antivenoms have
no maximum dosage; only it is advised to use the minimum dosage necessary
to counteract the effects of the venom.
The cost of antivenom will vary according to the market, but given that
it is expensive to produce and generally in low demand, the price PER
VIAL is likely to be $500-1000! (Remember that several vials are typically
required to treat a bite.)
Due to the cost, relatively short shelf life, and concerns over allergic
reactions, few snake researchers or hobbyists maintain their own antivenom
stockpiles. For native species, antivenom is usually available quite
readily, but the same cannot be said of exotic species. As part of their
snake bite emergency plan, those keeping exotics usually research the
location of the nearest available antivenom. Antivenom banks have become
popular as a way for keepers to divvy up the costs of maintaining antivenoms
for exotic species.
for The Miami-Dade Fire Rescue Antivenin
Bank information and antivenom list.
bite wound will typically consist of 4 curved lines of tiny pinpricks.
These correspond with the rows of sharp, pointy teeth. The bite may
bleed more than one might expect, due to the sharpness of the teeth
and anticoagulant properties of the snake saliva. In some cases, the
bite area may mildly itch.
salivas of some non-venomous colubrids have , in rare instances ,
caused mild to moderate poisoning in humans . In the United States
, people have had reactions to bites of the black-striped snake (Coniophanes
imperialis) , ringneck snake (Diadophis punctatus) , western hognose
snake (Heterodon nasicus) , cat-eyed snake (Leptodeira septentrionalis)
, Mexican vinesnake (Oxybelis aeneus) , western terrestrial gartersnake
( Thamnophis elegans) , common gartersnake (T . sirtalis) , and lyre
snake (Trimorphodon biscutatus) . None of these snakes’ venom-delivery
systems operates efficiently on humans ; most must chew for the venom
to enter the wound . Symptoms of envenomation appear in fewer than
1% of gartersnake bites , though such bites are common among people
who handle these snakes . It is possible that the salivas of all colubrids
have a toxic component , and that some susceptible than others .
you are bitten by a non venomous snake you should :
the bite area with soap and water
any souvenir's (teeth) left behind with tweezers
bandage if needed
to Help Avoid Snake Bite
trim hedges, keep your lawn mowed and remove brush from your yard
and any nearby vacant lots. This will reduce the number of places
where snakes like to live.
allow children to play in vacant, weed-infested lots.
Always use tongs when moving firewood, brush or lumber. This will
safely expose any snakes that may be hidden underneath.
moving through areas with tall grass and weeds, always poke at the
ground ahead of you with a long stick or pole to scare any snakes
Wear loose, long pants and tall boots when working or walking in
areas where snakes are likely to be.
not lift up rocks or wood with hands or feet.
Never handle snakes, even dead ones. If you see a snake, slowly
back away from it. Most people are bitten trying to get to close.
Be aware of snakes if you are swimming or wading in rivers, lakes
or other water such as flooding.
to identify poisonous snakes and avoid them.
a good flashlite at night, this includes hiking trails, campsites,
and even your front yard! Many snakes become more active at night,
especially around dusk and dawn during the warmest parts of summer
sleep on a cot when camping in snake-infested areas.
the summer months during times of drought, use extreme caution when
in and around areas of water, regardless if it is a trickle of water
from the pump of your swimming pool or a large lake. Also
pay attention to your outside air conditioning unit during hot summer
months. It is usually elevated off the ground , it is shaded and cool,
and has an occasional trickle of water under their, making it the
perfect place to hang out during the heat of the day.Most everything
living thing needs water to survive, including snakes.
Many Snakes Are Venomous ?
Four families of snakes (Atractaspididae,
Colubridae, Elapidae, and Viperidae)
include species dangerous to humans, a total of roughly 450 species
or about 19% of all snake species .
Snakes Species of the United States
Venomous species of Alabama are marked in
a species to see pictures)
is an ongoing debate on whether or not the Timber Rattlesnake and
the Canebrake Rattlesnake are of the same species. For the sake
of this table, they will be listed as seperate species.
number of bites
|Central and South America
the 45,000 snakebites reported annually in the United States, 7,000
to 8,000 are are caused by venomous snakes.
fatalities result, placing the chance of survival at roughly 499
out of 500.
3,000 are classed as "illegitimate," meaning these bites occurred
while the victim handled or molested the snake.
percent of natural bites are below the knee.
percent are dry. Strikes against humans are generally defensive
actions. It is estimated that no venom is purposely injected about
half the time.
of snakebite is higher in males than in females (Most likely due
to alcohol and testostorone) Young adults that are in the 18-28
age group are bitten most commonly.
majority of bites in the United States occur in the southwestern part
of the country, in part because rattlesnake populations in the eastern
states are much lower.
state of North Carolina has the highest frequency of reported snakebites,
averaging approximately 19 bites per 100,000 persons. The national
average is roughly 4 bites per 100,000 persons.
the US, Copperheads are responsible for about 25% of venomous snake
bites. The American Association of Poison Control Centers (AAPCC)
has reported no mortality from Copperhead envenomation since its first
annual report in 1983.
Coral Snake Statistics
the US, Coral Snakes are responsible for less than 1% of venomous snake
bites in the US. Most people bitten by coral snakes are handling them
intentionally. Probably less than 20 bites occur per year (though 61
alleged bites were reported to the American Association of Poison Control
Centers in 1998). No deaths related to Coral Snake bites have been reported
in the US since Coral Snake antivenom became available. Before that
time, the estimated case fatality rate was 10%.
No deaths related to coral snake bites have been reported in the United
States since coral snake antivenom became available. Before that time,
the estimated case fatality rate was 10%, and the cause of death was
respiratory or cardiovascular failure. Patients who survive the bite
may require respiratory support for up to a week and may suffer persistent
weakness for weeks to months.
the US, Cottonmouth are responsible for about 10% of venomous snake
bites. The American Association of Poison Control Centers (AAPCC) has
reported no mortality from Cottonmouth envenomation since its first
annual report in 1983.
The American Association of Poison Control Centers (AAPCC)
has reported only one death from moccasin envenomation since its first
annual report in 1983. Prospective studies of morbidity from moccasin
envenomation have not been conducted. However, in two retrospective
studies of copperhead victims, patients missed a median of 2 or 6 weeks
(includes all species) cause about 75% of all bites by identified venomous
snakes in the US. Dry bites, in which there is no envenomation, occur
in as many as 50% of strikes. An average of 5.5 deaths per year occur
as a result of snake bite in the US, most of these after Rattlesnake
Fewer than half a dozen deaths occur per year as a result of snakebite
in the United States; most are caused by rattlesnake bites. Estimates
of deaths each year from snakebite range from 30,000-110,000 worldwide.
Up to 5 times as many individuals experience permanent morbidity.