A
snakebite is an injury caused by a bite from a
snakeSnakes are elongate legless carnivorous reptiles of the suborder Serpentes that can be distinguished from legless lizards by their lack of eyelids and external ears. Like all squamates, snakes are ectothermic amniote vertebrates covered in overlapping scales...
, often resulting in puncture wounds inflicted by the animal's
fangFang is a mammal's canine tooth.Fang may also refer to:* A snake's poison-injecting tooth: see snake venom* The Fang people of Central Africa* The Fang language spoken by these people...
s and sometimes resulting in
envenomationEnvenomation is the process by which venom is injected into some animal by the bite of a venomous animal. Many kinds of animals, including mammals , reptiles , spiders , insects , employ venom for hunting and for self defense...
. Although the majority of snake species are non-venomous and typically kill their prey with
constriction-Snakes:Constriction is a method used by various snake species to kill their prey. Although some species of venomous and mildly-venomous snakes do use constriction to subdue their prey, most snakes which use constriction lack venom. The snake initially strikes at its prey and holds on, pulling the...
rather than
venomSnake venom is highly modified saliva that is produced by special glands of certain species of snakes. The gland which secretes the zootoxin is a modification of the parotid salivary gland of other vertebrates, and is usually situated on each side of the head below and behind the eye, invested in...
, venomous snakes can be found on every continent except
Antarctica| style="border-top:solid 1px #ccd2d9; padding:0.4em 1em 0.4em 0; vertical-align:top;" | 14,000,000 km
2 280,000 km
2 13,720,000 km
2 |-! style="border-top: solid 1px #ccd2d9; padding: 0.4em 1em 0.4em 0; vertical-align: top;...
. Snakes often bite their prey as a method of hunting, but also for defensive purposes against predators, such as humans. Since the physical appearance of snakes may differ, there is often no practical way to identify a species and professional medical attention should be sought.
The outcome of snake bites depends on numerous factors, including the species of snake, the area of the body bitten, the amount of venom injected, and the health conditions of the victim. Feelings of terror and panic are common after a snakebite and can produce a characteristic set of symptoms mediated by the
autonomic nervous systemThe autonomic nervous system is the part of the peripheral nervous system that acts as a control system functioning largely below the level of consciousness, and controls visceral functions. The ANS affects heart rate, digestion, respiration rate, salivation, perspiration, diameter of the pupils,...
, such as a
racing heartTachycardia comes from the Greek words tachys and kardia . Tachycardia typically refers to a heart rate that exceeds the normal range for a resting heartrate...
and
nauseaNausea is the sensation of unease and discomfort in the stomach with an urge to vomit.-Causes:...
. Bites from non-venomous snakes can also cause injury, often due to lacerations caused by the snake's fangs, or from a resulting infection. A bite may also trigger an anaphylactic reaction, which is potentially fatal. First aid recommendations for bites depend on the snakes inhabiting the region, as effective treatments for bites inflicted by some species can be ineffective for others.
The number of fatalities attributed to snake bites varies greatly by geographical area. Although deaths are relatively rare in
EuropeEurope is, by convention, one of the world's seven continents. Comprising the westernmost peninsula of Eurasia, Europe is generally divided from Asia to its east by the water divide of the Ural Mountains, the Ural River, the Caspian Sea, the Caucasus Mountains , and the Black Sea to the southeast...
and
North AmericaNorth America is the northern continent of the Americas, situated in the Earth's northern hemisphere and in the western hemisphere. It is bordered on the north by the Arctic Ocean, on the east by the North Atlantic Ocean, on the southeast by the Caribbean Sea, and on the west by the North Pacific...
, the morbidity and mortality associated with snake bites is a serious public health problem in many regions of the world, particularly in rural areas lacking medical facilities. Further, while
South AsiaSouth Asia, also known as Southern Asia, is the southern region of the Asian continent, which comprises the sub-Himalayan countries and, for some authorities , also includes the adjoining countries on the west and the east...
,
Southeast AsiaManila
Bangkok
Ho Chi Minh City
Kuala Lumpur
Singapore
Yangon
Bandung
Hanoi
Surabaya
Taichung
Kaohsiung
Medan|-|}...
, and
sub-Saharan AfricaSub-Saharan Africa is a geographical term used to describe the area of the African continent which lies south of the Sahara, or those African countries which are fully or partially located south of the Sahara...
report the highest number of bites, there is also a high incidence in the Neotropics and other equatorial and subtropical regions. Each year tens of thousands of people die from snake bites, yet the risk of being bitten can be lowered with preventative measures, such as wearing protective footwear and avoiding areas known to be inhabited by dangerous snakes.
Signs and symptoms
The most common symptoms of all snakebites are overwhelming fear, panic, and emotional instability, which may cause symptoms such as
nauseaNausea is the sensation of unease and discomfort in the stomach with an urge to vomit.-Causes:...
and
vomitingVomiting is the forceful expulsion of the contents of one's stomach through the mouth and sometimes the nose. Undesired vomiting may result from many causes, ranging from gastritis or poisoning to brain tumors, or elevated intracranial pressure...
,
diarrheaIn medicine, diarrhea , also spelled diarrhoea , is the condition of having frequent loose or liquid bowel movements. Acute diarrhea is a common cause of death in developing countries and the second most common cause of infant deaths worldwide...
,
vertigoVertigo is a specific type of dizziness, a major symptom of a balance disorder. It is the sensation of spinning or swaying while the body is actually stationary with respect to the surroundings.The effects of vertigo may be slight...
, fainting,
tachycardiaTachycardia comes from the Greek words tachys and kardia . Tachycardia typically refers to a heart rate that exceeds the normal range for a resting heartrate...
, and cold, clammy skin. Television, literature, and folklore are in part responsible for the hype surrounding snakebites, and a victim may have unwarranted thoughts of imminent death.
Dry snakebitesA dry bite is a bite by a venomous animal in which no venom is released. Dry snake bites are called "Venomous snake bite without envenoming". Dry bites can occur from all snakes, but their frequency varies from species to species. For example, brown snakes can inflict dry bites 80% of the time...
, and those inflicted by a non-venomous species, can still cause severe injury to the victim. There are several reasons for this: a snakebite which is not treated properly may become infected (as is often reported by the victims of viper bites whose fangs are capable of inflicting deep puncture wounds), the bite may cause
anaphylaxisAnaphylaxis is an acute systemic and severe type I hypersensitivity allergic reaction in humans and other mammals. The term comes from the Greek words ανα ana and φύλαξις phylaxis . Minute amounts of allergens may cause a life-threatening anaphylactic reaction...
in certain people, and the snake's saliva and fangs may harbor many dangerous microbial contaminants, including
Clostridium tetaniClostridium tetani is a rod-shaped, anaerobic bacterium of the genus Clostridium. Like other Clostridium species, it is Gram-positive, and its appearance on a gram stain resembles tennis rackets or drumsticks. C. tetani is found as spores in soil or as parasites in the gastrointestinal tract of...
. If neglected, an infection may spread and potentially kill the victim.
Most snakebites, whether by a venomous snake or not, will have some type of local effect. There is minor pain and
rednessErythema is redness of the skin, which can be caused by several things, including capillary congestion.-Causes:It can be caused by infection, massage, electrical treatment, acne medication, allergies, exercise, solar radiation , cutaneous radiation syndrome, or waxing and plucking of the hairs...
in over 90% of cases, although this varies depending on the site. Bites by
vipersThe Viperidae are a family of venomous snakes found all over the world, except in Antarctica, Australia, New Zealand, Ireland, Madagascar, Hawaii and the Arctic Circle. All have relatively long hinged fangs that permit deep penetration and injection of venom...
and some
cobraA cobra is a venomous snake, which is a member of the family Elapidae . The name is short for cobra de capelo , which is Portuguese for "snake with hood," or "hood-snake." When disturbed, most of these snakes can rear up and spread their neck in a characteristic threat display...
s may be extremely painful, with the local tissue sometimes becoming tender and severely
swollenEdema or oedema , formerly known as dropsy or hydropsy, is an abnormal accumulation of fluid beneath the skin, or in one or more cavities of the body...
within 5 minutes. This area may also bleed and blister. Other common initial symptoms of pitviper bites include lethargy, weakness, nausea, and vomiting. Symptoms may become more life-threatening over time, developing into
hypotensionIn physiology and medicine, hypotension refers to an abnormally low blood pressure. This is best understood as a physiologic state, rather than a disease. It is often associated with shock, though not necessarily indicative of it. Hypotension is the opposite of hypertension, which is high blood...
,
tachypneaTachypnea is characterized by rapid breathing.It is not identical with hyperventilation - tachypnea may be necessary for a sufficient gas-exchange of the body, for example after exercise, in which case it is not hyperventilation.Tachypnea differs from hyperpnea in that tachypnea is rapid shallow...
, severe tachycardia, altered
sensoriumThe term sensorium refers to the sum of an organism's perception, the "seat of sensation" where it experiences and interprets the environments within which it lives. The term originally enters English from the Late Latin in the mid-17th century, from the stem sens-...
, and
respiratory failureThe term respiratory failure, in medicine, is used to describe inadequate gas exchange by the respiratory system, with the result that arterial oxygen and/or carbon dioxide levels cannot be maintained within their normal ranges. A drop in blood oxygenation is known as hypoxemia; a rise in arterial...
.
Interestingly, bites caused by the Mojave rattlesnake,
coral snakeThe coral snakes are a large group of elapid snakes that can be divided into two distinct groups: New World coral snakes and Old World Calliophis snakes. There are three genera among New World coral snakes that consist of over 65 recognized species.-North American Coloration Patterns:Coral snakes...
, and the
speckled rattlesnakeCrotalus mitchellii is a venomous pitviper species found in the Southwestern United States, and in northern Mexico. It was named in honor of Silas Weir Mitchell , a medical doctor who also studied rattlesnake venoms...
reportedly cause little or no pain despite being serious injuries. Victims may also describe a "rubbery," "minty," or "metallic" taste if bitten by certain species of rattlesnake.
Spitting cobraA spitting cobra is one of several species of cobras that have the ability to eject venom from their fangs when defending themselves against predators. The sprayed venom is harmless to intact skin...
s and
rinkhalsThe Rinkhals also called the Ringhals or Ring-necked Spitting Cobra is a venomous elapid species found in parts of southern Africa...
es can spit venom in their victims' eyes. This results in immediate pain,
ophthalmoparesisOphthalmoparesis or ophthalmoplegia is a physical finding in certain neurologic illnesses. It refers to paralysis of the one or more extraocular muscles which are responsible for eye movements.-Classification:...
, and sometimes
blindnessBlindness is the condition of lacking visual perception due to physiological or neurological factors.Various scales have been developed to describe the extent of vision loss and define blindness...
.
Some Australian elapids and most viper envenomations will cause
coagulopathyCoagulopathy is a defect in the body's mechanism for blood clotting, causing bleeding diathesis.-Causes:...
, sometimes so severe that a person may bleed spontaneously from the mouth, nose, and even old, seemingly-healed wounds. Internal organs may bleed, including the brain and intestines and will cause
ecchymosisAn ecchymosis is the medical term for a subcutaneous hematoma larger than 1cm, commonly called a bruise. The red blood cells are phagocytosed and degraded by macrophages, The blue-red color produced is from the enzymatic conversion of hemoglobin into billirubin, which is more blue-green...
(bruising) of the victim's skin.
Venom emitted from elapids, including
cobrasNaja is a genus of venomous elapid snakes. Although there are several other genera that share the common name, naja are the most recognized, and most widespread group of snakes commonly known as cobras. The genus Naja consists of from 20 to 22 species, but has undergone several taxonomic revisions...
,
kraitsBungarus is a genus of venomous elapid snakes found in South and South-East Asia. Commonly referred to as kraits, there are 12 species and 5 subspecies.- Distribution :...
, mambas,
sea snakesSea Snakes were a Canadian indie rock band, formed in 2002 and disbanded in 2005. The band consisted of vocalist and guitarist Jimmy McIntyre, guitarist Kristian Galberg, bassist and saxophonist Jeremy Strachan, keyboardist Shaw-Han Liem and drummer Nathan Lawr.Strachan played in the defunct band...
, and many Australian species, contain toxins which attack the nervous system, causing
neurotoxicityNeurotoxicity occurs when the exposure to natural or artificial toxic substances, which are called neurotoxins, alters the normal activity of the nervous system in such a way as to cause damage to nervous tissue. This can eventually disrupt or even kill neurons, key cells that transmit and process...
. The victim may present with strange disturbances to their vision, including blurriness.
ParesthesiaParesthesia is a sensation of tingling, pricking, or numbness of a person's skin with no apparent long-term physical effect. It is more generally known as the feeling of "pins and needles" or of a limb "falling asleep"...
throughout the body, as well as difficulty speaking and breathing may be reported. Nervous system problems will cause a huge array of symptoms, and those provided here are not exhaustive. If the victim is not treated immediately they may die from
respiratory failureThe term respiratory failure, in medicine, is used to describe inadequate gas exchange by the respiratory system, with the result that arterial oxygen and/or carbon dioxide levels cannot be maintained within their normal ranges. A drop in blood oxygenation is known as hypoxemia; a rise in arterial...
.
Venom emitted from some Australian elapids, almost all vipers, and all sea snakes causes
necrosisNecrosis is the premature death of cells and living tissue. Necrosis is caused by external factors, such as infection, toxins , or trauma. This is in contrast to apoptosis, which is a naturally occurring cause of cellular death...
of muscle tissue. Muscle tissue will begin to die throughout the body, a condition known as
rhabdomyolysisRhabdomyolysis is the rapid breakdown of skeletal muscle due to injury to muscle tissue. The muscle damage may be caused by physical , chemical, or biological factors...
. Dead muscle cells may even clog the kidney which filters out proteins. This, coupled with
hypotensionIn physiology and medicine, hypotension refers to an abnormally low blood pressure. This is best understood as a physiologic state, rather than a disease. It is often associated with shock, though not necessarily indicative of it. Hypotension is the opposite of hypertension, which is high blood...
, can lead to
acute renal failureAcute renal failure , also known as acute kidney failure or acute kidney injury, is a rapid loss of renal function due to damage to the kidneys, resulting in retention of nitrogenous and non-nitrogenous waste products that are normally excreted by the kidney...
, and, if left untreated, eventually death.
Pathophysiology
Since
envenomationEnvenomation is the process by which venom is injected into some animal by the bite of a venomous animal. Many kinds of animals, including mammals , reptiles , spiders , insects , employ venom for hunting and for self defense...
is completely voluntary, all venomous snakes are capable of biting without injecting venom into their victim. Snakes may deliver such a "
dry biteA dry bite is a bite by a venomous animal in which no venom is released. Dry snake bites are called "Venomous snake bite without envenoming". Dry bites can occur from all snakes, but their frequency varies from species to species. For example, brown snakes can inflict dry bites 80% of the time...
" rather than waste their venom on a creature too large for them to eat. However, the percentage of dry bites varies between species: 50% of bites from the normally timid
coral snakeThe coral snakes are a large group of elapid snakes that can be divided into two distinct groups: New World coral snakes and Old World Calliophis snakes. There are three genera among New World coral snakes that consist of over 65 recognized species.-North American Coloration Patterns:Coral snakes...
do not result in envenomation, whereas only 25% of
pitviperThe Crotalinae, or crotalines, are a subfamily of venomous vipers found in Asia and the Americas. They are distinguished by the presence of a heat-sensing pit organ located between the eye and the nostril on either side of the head...
bites are dry. Furthermore, some snake
generaGenera is a commercial operating system and development environment for Lisp machines developed by Symbolics. It is essentially a fork of an earlier operating system originating on the MIT AI Lab's Lisp machines which Symbolics had used in common with LMI and Texas Instruments...
, such as
rattlesnakeRattlesnakes are a group of venomous snakes, genera Crotalus and Sistrurus. They belong to the subfamily of venomous snakes known commonly as pit vipers.-Overview:...
s, significantly increase the amount of venom injected in defensive bites compared to predatory strikes.
Some dry bites may also be the result of imprecise timing on the snake's part, as venom may be prematurely released before the fangs have penetrated the victim's flesh. Even without venom, some snakes, particularly large constrictors such as those belonging to the Boidae and Pythonidae families, can deliver damaging bites; large specimens often cause severe lacerations as the victim or the snake itself pull away, causing the flesh to be torn by the needle-sharp recurved teeth embedded in the victim. While not as life-threatening as a bite from a venomous species, the bite can be at least temporarily debilitating and could lead to dangerous infections if improperly dealt with.
While most snakes must open their mouths before biting, African and Middle Eastern snakes belonging to the family
AtractaspididaeThe Atractaspididae are a family of snakes found in Africa and the Middle East. Currently, 12 genera are recognized.-Description:This family includes many genera formerly classed in other families, on the basis of fang type. It includes fangless , rear-fanged , fixed-fanged , and viper-like species...
are able to fold their fangs to the side of their head without opening their mouth and jab at victims.
Snake venom
It has been suggested that snakes evolved the mechanisms necessary for venom formation and delivery sometime during the
MioceneThe Miocene is a geological epoch of the Neogene period and extends from about 23.03 to 5.33 million years before the present . The Miocene was named by Sir Charles Lyell. Its name comes from the Greek words and and means "less recent" because it has 18% fewer modern sea invertebrates than the...
epoch. During the mid-
TertiaryThe Tertiary is a term for a geologic period 65 million to 2.588 million years ago. The Tertiary covered the time span between the superseded Secondary period and the Quaternary...
, most snakes were large
ambush predatorAmbush predators or sit-and-wait predators are carnivorous animals that capture prey by stealth or cunning, not by speed or necessarily by strength. These organisms usually hide motionless and wait for prey to come within striking distance. They are often camouflaged, and may be solitary...
s belonging to the superfamily
HenophidiaHenophidia is a superfamily of the suborder Serpentes that contains boas, pythons and other snakes. Snakes belonging to superfamily Henophidia are considered to be more primitive than those belonging to the other superfamilies - namely, Typhlopoidea and Xenophidia.- Families :* Aniliidae - coral...
, which use constriction to kill their prey. As open grasslands replaced forested areas in parts of the world, some snake families evolved to become smaller and thus more agile. However, subduing and killing prey became more difficult for the smaller snakes, leading to the evolution of snake venom. Other research on
ToxicoferaToxicofera , is a hypothetical clade which represents about 4600 species of extant squamates It encompasses all venomous reptile species, as well as numerous related non-venomous species....
, a hypothetical
cladeA clade is a term used in modern alpha taxonomy, the scientific classification of living and fossil organisms, to describe a monophyletic group, defined as a group consisting of a single common ancestor and all its descendants.[The term "monophyletic group" is used in this article...]
thought to be ancestral to most living reptiles, suggests an earlier time frame for the evolution of snake venom, possibly to the order of tens of millions of years, during the
Late CretaceousThe Late Cretaceous is the youngest of two epochs in which the Cretaceous period is divided in the geologic timescale. Rock strata from this epoch form the Upper Cretaceous series...
.
Snake venom is produced in modified
parotid glandThe parotid gland is the largest of the salivary glands. It is found wrapped around the mandibular ramus, and it secretes saliva through Stensen's duct into the oral cavity, to facilitate mastication and swallowing.-Location:...
s normally responsible for secreting saliva. It is stored in structures called alveoli behind the animal's eyes, and ejected voluntarily through its hollow tubular fangs. Venom is composed of hundreds to thousands of different
proteinProteins are organic compounds made of amino acids arranged in a linear chain and folded into a globular form. The amino acids in a polymer chain are joined together by the peptide bonds between the carboxyl and amino groups of adjacent amino acid residues...
s and enzymes, all serving a variety of purposes, such as interfering with a prey's cardiac system or increasing tissue permeability so that venom is absorbed faster.
Venom in many snakes, such as pitvipers, affects virtually every organ system in the human body and can be a combination of many toxins, including cytotoxins, hemotoxins, neurotoxins, and
myotoxinMyotoxins are small, basic peptides found in snake venoms, such as in that of certain rattlesnakes. This involves a non-enzymatic mechanism that leads to severe muscle necrosis...
s, allowing for an enormous variety of symptoms. Earlier, the venom of a particular snake was considered to be one kind only i.e. either hemotoxic or neurotoxic, and this erroneous belief may still persist wherever the updated literature is hard to access.
The strength of venom differs markedly between species and even more so between families, but
AustraliaAustralia , officially the Commonwealth of Australia, is a country in the Southern Hemisphere comprising the continental mainland , the island of Tasmania, and numerous smaller islands in the Indian and Pacific Oceans...
n snakes are known to possess particularly potent venom: 10 of the world's most venomous snakes, as measured by
LD50In toxicology, the median lethal dose, LD50 , LC50 or LCt50 of a toxic substance or radiation is the dose required to kill half the members of a tested population...
in mice, inhabit the continent. Of these, the inland taipan possesses the most potent venom, but because the snake is timid and rarely encountered by humans, bites are extremely rare. The amount of venom produced also differs among species, with the Gaboon viper able to potentially deliver from 5–7 ml (450–600 mg) of venom in a single bite, the most of any snake.
Prevention
Snakes are most likely to bite when they feel threatened, are startled, provoked, or have no means of escape when cornered. Encountering a snake is always considered dangerous and it is recommended to leave the vicinity. There is no practical way to safely identify any snake species as appearances may vary dramatically.
Snakes are likely to approach residential areas when attracted by prey, such as rodents. Practicing regular
pest controlPest control refers to the regulation or management of a species defined as a pest, usually because it is perceived to be detrimental to a person's health, the ecology or the economy....
can reduce the threat of snakes considerably. It is beneficial to know the species of snake that are common in local areas, or while traveling or hiking. Areas of the world such as
AfricaAfrica is the world's second-largest and second most-populous continent, after Asia. At about 30.2 million km² including adjacent islands, it covers 6% of the Earth's total surface area and 20.4% of the total land area. With a billion people in 61 territories, it accounts for about 14.8% of the...
,
AustraliaAustralia , officially the Commonwealth of Australia, is a country in the Southern Hemisphere comprising the continental mainland , the island of Tasmania, and numerous smaller islands in the Indian and Pacific Oceans...
, the Neotropics, and southern Asia are inhabited by many highly dangerous species. Being wary of snake presence and ultimately avoiding it when known is strongly recommended.
When in the wilderness, treading heavily creates ground vibrations and noise, which will often cause snakes to flee from the area. However, this generally only applies to
North AmericaNorth America is the northern continent of the Americas, situated in the Earth's northern hemisphere and in the western hemisphere. It is bordered on the north by the Arctic Ocean, on the east by the North Atlantic Ocean, on the southeast by the Caribbean Sea, and on the west by the North Pacific...
as some larger and more aggressive snakes in other parts of the world, such as
king cobraThe King Cobra is the world's longest venomous snake, with a length that can be as large as about 5.6 m . This species is widespread throughout Southeast Asia and parts of India, and is found mostly in forested areas. Note that this species is highly aggressive and dangerous...
s and
black mambaThe Black Mamba , is an elapid snake and is one of Africa's most dangerous and feared snakes. It has a wide range of known locations throughout Africa. The black mamba is found in Somalia, Ethiopia, Kenya, Botswana,Uganda, Zambia, Zimbabwe, Angola, Namibia, Malawi, Mozambique, South Africa and the...
s, will protect their territory. When dealing with direct encounters it is best to remain silent and motionless. If the snake has not yet fled it is important to step away slowly and cautiously.
The use of a flashlight when engaged in camping activities, such as gathering firewood at night, can be helpful. Snakes may also be unusually active during especially warm nights when ambient temperatures exceed . It is advised not to reach blindly into hollow logs, flip over large rocks, and enter old
cabinsA log cabin is a small house built from logs. It is a simple type of log house. A distinction should be drawn between the traditional meanings of "log cabin" and "log house." "Log cabin" generally denotes a simple one, or one-and-one-half story structure, somewhat impermanent, and less finished or...
or other potential snake hiding-places. When
rock climbingClimbing is the activity of using one's hands and feet to ascend a steep object. It is done both for recreation and professionally, as part of activities such as maintenance of a structure, or military operations.Climbing activities include:* Bouldering: Ascending boulders or small...
, it is not safe to grab ledges or crevices without examining them first, as snakes are
cold-bloodedEctothermic, from the Greek ectos, "outside" and therme, "heat," refers to organisms that control body temperature through external means. As a result, organisms are dependent on environmental heat sources and have relatively low metabolic rates. For example, many reptiles regulate their body...
and often sunbathe atop rock ledges.
Pet owners of domestic animals or snakes should be wary that a snake is capable of causing injury and that is necessary to always act with caution. When handling snakes it is never wise to consume
alcoholic beverageAn alcoholic beverage is a drink that contains ethanol . Alcoholic beverages are divided into three general classes: beers, wines, and spirits....
s. In the United States more than 40% of snakebite victims intentionally put themselves in harm's way by attempting to capture wild snakes or by carelessly handling their dangerous pets—40% of that number had a blood alcohol level of 0.1 percent or more.
It is also important to avoid snakes that appear to be dead, as some species will actually roll over on their backs and stick out their tongue to fool potential threats. A snake's detached head can immediately act by
reflexA reflex action, also known as a reflex, is an involuntary and nearly instantaneous movement in response to a stimulus. In most contexts, in particular those involving humans, reflex actions are mediated via the reflex arc; this is not always true in other animals, nor does it apply to casual uses...
and potentially bite. The induced bite can be just as severe as that of a live snake.
Dead snakes are also incapable of regulating the venom they inject, so a bite from a dead snake can often contain large amounts of venom.
Treatment
It is not an easy task determining whether or not a bite by any species of snake is life-threatening. A bite by a North American
copperheadAgkistrodon contortrix is a species of venomous snake found in North America, a member of the Crotalinae subfamily. Common names for the species include Copperhead and moccasin. The behaviour of Agkistrodon contortrix may lead to accidental encounters with humans...
on the ankle is usually a moderate injury to a healthy adult, but a bite to a child's abdomen or face by the same snake may be fatal. The outcome of all snakebites depends on a multitude of factors: the size, physical condition, and temperature of the snake, the age and physical condition of the victim, the area and tissue bitten (e.g., foot, torso, vein or muscle, etc.), the amount of venom injected, the time it takes for the patient to find treatment, and finally the quality of that treatment. Promptly securing qualified medical treatment is the best course of action, and conservative management in the meantime is recommended.
Snake identification
Identification of the snake is important in planning treatment in certain areas of the world, but is not always possible. Ideally the dead snake would be brought in with the patient, but in areas where snake bite is more common, local knowledge may be sufficient to recognize the snake. However, in countries where polyvalent antivenoms are available, such as North America, identification of snake is not a high priority item.
The three types of venomous snakes that cause the majority of major clinical problems are
vipersThe Viperidae are a family of venomous snakes found all over the world, except in Antarctica, Australia, New Zealand, Ireland, Madagascar, Hawaii and the Arctic Circle. All have relatively long hinged fangs that permit deep penetration and injection of venom...
,
kraitsBungarus is a genus of venomous elapid snakes found in South and South-East Asia. Commonly referred to as kraits, there are 12 species and 5 subspecies.- Distribution :...
, and
cobrasNaja is a genus of venomous elapid snakes. Although there are several other genera that share the common name, naja are the most recognized, and most widespread group of snakes commonly known as cobras. The genus Naja consists of from 20 to 22 species, but has undergone several taxonomic revisions...
. Knowledge of what species are present locally can be crucial, as is knowledge of typical signs and symptoms of envenomation by each type of snake. A scoring systems can be used to try and determine the biting snake based on clinical features, but these scoring systems are extremely specific to particular geographical areas.
First aid
Snakebite
first aidFirst aid is the provision of initial care for an illness or injury. It is usually performed by a lay person to a sick or injured casualty until definitive medical treatment can be accessed. Certain self-limiting illnesses or minor injuries may not require further medical care past the first aid...
recommendations vary, in part because different snakes have different types of venom. Some have little local effect, but life-threatening systemic effects, in which case containing the venom in the region of the bite by pressure immobilization is highly desirable. Other venoms instigate localized tissue damage around the bitten area, and immobilization may increase the severity of the damage in this area, but also reduce the total area affected; whether this trade-off is desirable remains a point of controversy.
Because snakes vary from one country to another, first aid methods also vary. As always, this article is not a legitimate substitute for professional medical advice. Readers are strongly advised to obtain guidelines from a reputable first aid organization in their own region, and to be wary of homegrown or anecdotal remedies.
However, most first aid guidelines agree on the following:
- Protect the patient (and others, including yourself) from further bites. While identifying the species is desirable in certain regions, do not risk further bites or delay proper medical treatment by attempting to capture or kill the snake. If the snake has not already fled, carefully remove the victim from the immediate area.
- Keep the victim calm. Acute stress reaction
Acute stress over reaction is a psychological condition arising in response to a terrifying event...
increases blood flow and endangers the patient. Keep people near the patient calm. PanicPanic is a sudden fear which dominates or replaces thinking and often affects groups of people or animals. Panics typically occur in disaster situations, or violent situations which may endanger the overall health of the affected group...
is infectious and compromises judgment.
- Call for help to arrange for transport to the nearest hospital emergency room, where antivenom for snakes common to the area will often be available.
- Make sure to keep the bitten limb in a functional position and below the victim's heart level so as to minimize blood returning to the heart and other organs of the body.
- Do not give the patient anything to eat or drink. This is especially important with consumable alcohol, a known vasodilator which will speed up the absorption of venom. Do not administer stimulant
Stimulants, also sometimes called psychostimulants, are psychoactive drugs which induce temporary improvements in either mental or physical function or both. Examples of these kinds of effects may include enhanced alertness, wakefulness, and locomotion, among others...
s or pain medications to the victim, unless specifically directed to do so by a physician.
- Remove any items or clothing which may constrict the bitten limb if it swells (rings, bracelets, watches, footwear, etc.)
- Keep the victim as still as possible.
- Do not incise the bitten site.
Many organizations, including the
American Medical AssociationThe American Medical Association , founded in 1847 and incorporated 1897, is the largest association of physicians and medical students in the United States. While its membership has declined in recent years, it claims approximately 20% of practicing physicians as members...
and
American Red CrossThe American Red Cross is a humanitarian organization that provides emergency assistance, disaster relief and education inside the United States, and is the designated U.S...
, recommend washing the bite with soap and water. However, do not attempt to clean the area with any type of chemical. Australian recommendations for snake bite treatment strongly recommend against cleaning the wound. Traces of venom left on the skin/bandages from the strike can be used in combination with a snake bite identification kit to identify the species of snake. This speeds determination of which antivenom to administer in the emergency room.
Pressure immobilization
In 1979, Australia's
National Health and Medical Research CouncilThe National Health and Medical Research Council is Australia's peak funding body for medical research, with a budget of nearly one billion dollars a year...
formally adopted pressure immobilization as the preferred method of first aid treatment for snakebites in Australia. As of 2009, clinical evidence for pressure immobilization remains limited, with current evidence based almost entirely on anecdotal case reports. This has led most international authorities to question its efficacy. Despite this, all reputable first aid organizations in Australia recommend pressure immobilization treatment; however, it is not widely adhered to, with one study showing that only a third of snakebite patients attempt pressure immobilization.
Pressure immobilization is not appropriate for cytotoxic bites such as those inflicted by most
vipersThe Viperidae are a family of venomous snakes found all over the world, except in Antarctica, Australia, New Zealand, Ireland, Madagascar, Hawaii and the Arctic Circle. All have relatively long hinged fangs that permit deep penetration and injection of venom...
, but may be effective against neurotoxic venoms such as those of most elapids. Developed by medical researcher
Struan SutherlandStruan Keith Sutherland AO was an Australian medical researcher who developed effective antivenoms and other treatments for people bitten or stung by venomous Australian wildlife.-Early life:...
in 1978, the object of pressure immobilization is to contain venom within a bitten limb and prevent it from moving through the lymphatic system to the vital organs. This therapy has two components: pressure to prevent lymphatic drainage, and immobilization of the bitten limb to prevent the pumping action of the
skeletal muscleSkeletal muscle is a form of striated muscle tissue existing under control of the somatic nervous system. It is one of three major muscle types, the others being cardiac and smooth muscle. As its name suggests, skeletal muscle is linked to bone by bundles of collagen fibers known as...
s.
Pressure is preferably applied with an elastic bandage, but any cloth will do in an emergency. Bandaging begins two to four inches above the bite (i.e. between the bite and the heart), winding around in overlapping turns and moving up towards the heart, then back down over the bite and past it towards the hand or foot. Then the limb must be held immobile: not used, and if possible held with a splint or sling. The bandage should be about as tight as when strapping a sprained ankle. It must
not cut off blood flow, or even be uncomfortable; if it is uncomfortable, the patient will unconsciously flex the limb, defeating the immobilization portion of the therapy. The location of the bite should be clearly marked on the outside of the bandages. Some peripheral
edemaEdema or oedema , formerly known as dropsy or hydropsy, is an abnormal accumulation of fluid beneath the skin, or in one or more cavities of the body...
is an expected consequence of this process.
Apply pressure immobilization as quickly as possible; if you wait until symptoms become noticeable you will have missed the best time for treatment. Once a pressure bandage has been applied, it should
not be removed until the patient has reached a medical professional. The combination of pressure and immobilization may contain venom so effectively that no symptoms are visible for more than 24 hours, giving the illusion of a dry bite. But this is only a delay; removing the bandage releases that venom into the patient's system with rapid and possibly fatal consequences.
Antivenom
Until the advent of antivenom, bites from some species of snake were almost universally fatal. Despite huge advances in emergency therapy, antivenom is often still the only effective treatment for envenomation. The first antivenom was developed in 1895 by French physician
Albert CalmetteLéon Charles Albert Calmette was a French physician, bacteriologist and immunologist, and an important officer of the Pasteur Institute. He discovered the Bacillus Calmette-Guérin, an attenuated form of Mycobacterium used in the BCG vaccine against tuberculosis...
for the treatment of
Indian cobraNaja naja is a species of venomous snake native to the Indian subcontinent which includes present day Pakistan, India, Bangladesh and Sri lanka. It is the most famous of the Big Four, the four most venomous snakes of India for which a single polyvalent antivenom has been created. Like other...
bites. Antivenom is made by injecting a small amount of venom into an animal (usually a horse or sheep) to initiate an immune system response. The resulting antibodies are then harvested from the animal's blood.
Antivenom is injected into the patient
intravenouslyIntravenous therapy or IV therapy is the giving of liquid substances directly into a vein. It can be intermittent or continuous; continuous administration is called an intravenous drip. The word intravenous simply means "within a vein", but is most commonly used to refer to IV therapy...
, and works by binding to and neutralizing venom enzymes. It cannot undue damage already caused by venom, so antivenom treatment should be sought as soon as possible. Modern antivenoms are usually polyvalent, making them effective against the venom of numerous snake species. Pharmaceutical companies which produce antivenom target their products against the species native to a particular area. Although some people may develop serious adverse reactions to antivenom, such as
anaphylaxisAnaphylaxis is an acute systemic and severe type I hypersensitivity allergic reaction in humans and other mammals. The term comes from the Greek words ανα ana and φύλαξις phylaxis . Minute amounts of allergens may cause a life-threatening anaphylactic reaction...
, in emergency situations this is usually treatable and hence the benefit outweighs the potential consequences of not using antivenom.
Outmoded treatments
The following treatments have all been recommended at one time or another, but are now considered to be ineffective or outright dangerous. Many cases in which such treatments appear to work are in fact the result of
dry biteA dry bite is a bite by a venomous animal in which no venom is released. Dry snake bites are called "Venomous snake bite without envenoming". Dry bites can occur from all snakes, but their frequency varies from species to species. For example, brown snakes can inflict dry bites 80% of the time...
s.
- Application of a tourniquet
An emergency tourniquet is a tightly tied band applied around a body part sometimes used in an attempt to stop severe traumatic bleeding. Tourniquets are also used during venipuncture and other medical procedures. Severe bleeding means the loss of more than 1,000 ml of blood. This flow of blood...
to the bitten limb is generally not recommended. There is no convincing evidence that it is an effective first aid tool as ordinarily applied. Tourniquets have been found to be completely ineffective in the treatment of Crotalus durissusCrotalus durissus is a venomous pitviper species found in South America. The most widely distributed member of its genus, this species poses a serious medical problem in many parts of its range...
bites, but some positive results have been seen with properly applied tourniquets for cobra venom in the PhilippinesThe Philippines officially known as the Republic of the Philippines, is a country in Southeast Asia with Manila as its capital city. It comprises 7,107 islands in the western Pacific Ocean....
. Uninformed tourniquet use is dangerous, since reducing or cutting off circulation can lead to gangreneGangrene is a complication of necrosis or cell death characterized by the decay of body tissues, which become black and malodorous. It is caused by infection or ischemia, such as from thrombosis. It is usually the result of critically insufficient blood supply and is often associated with...
, which can be fatal. The use of a compression bandage is generally as effective, and much safer.
- Cutting open the bitten area, an action often taken prior to suction, is not recommended since it causes further damage and increases the risk of infection.
- Sucking out venom, either by mouth or with a pump, does not work and may harm the affected area directly. Suction started after 3 minutes removes a clinically insignificant quantity—less than one thousandth of the venom injected—as shown in a human study. In a study with pigs, suction not only caused no improvement but led to necrosis
Necrosis is the premature death of cells and living tissue. Necrosis is caused by external factors, such as infection, toxins , or trauma. This is in contrast to apoptosis, which is a naturally occurring cause of cellular death...
in the suctioned area. Suctioning by mouth presents a risk of further poisoning through the mouth's mucous tissuesThe oral mucosa is the mucous membrane epithelium of the mouth. It can be divided into three categories.*Masticatory mucosa - keratinized stratified squamous epithelium, found on the dorsum of the tongue, hard palate and attached gingiva....
. The well-meaning family member or friend may also release bacteria into the victim's wound, leading to infection.
- Immersion in warm water or sour milk, followed by the application of snake-stones
Snake-stones also known as the viper's stone, black stone, the black stone, der schwarze Stein, la pierre noire, and la piedrita negra or serpent-stone are animal bones, which are widely used and promotedas a treatment for snake bite in Africa, South America and Asia...
(also known as la Pierre Noire), which are believed to draw off the poison in much the way a sponge soaks up water.
- Application of potassium permanganate
Potassium permanganate is the inorganic chemical compound KMnO
4, a water soluble salt consisting of equal mole amounts of potassium and permanganate ions. This salt, formerly known as permanganate of potash or Condy's crystals is a strong oxidizing agent...
.
- Use of electroshock therapy. Although still advocated by some, animal testing has shown this treatment to be useless and potentially dangerous.
In extreme cases, where the victims were in remote areas, all of these misguided attempts at treatment have resulted in injuries far worse than an otherwise mild to moderate snakebite. In worst case scenarios, thoroughly constricting tourniquets have been applied to bitten limbs, completely shutting off blood flow to the area. By the time the victims finally reached appropriate medical facilities their limbs had to be amputated.
Epidemiology
Most snakebites are caused by non-venomous snakes. Of the roughly 3,000 known species of snake found worldwide, only 15 percent are considered dangerous to humans. Snakes are found on every continent except
Antarctica| style="border-top:solid 1px #ccd2d9; padding:0.4em 1em 0.4em 0; vertical-align:top;" | 14,000,000 km
2 280,000 km
2 13,720,000 km
2 |-! style="border-top: solid 1px #ccd2d9; padding: 0.4em 1em 0.4em 0; vertical-align: top;...
. The most diverse and widely distributed snake family, the
colubridA colubrid is a snake that is a member of the family Colubridae. It is a broad classification of snakes that includes about two thirds of all snake species on earth...
s, has approximately 700 venomous species, but only five
generaGenera is a commercial operating system and development environment for Lisp machines developed by Symbolics. It is essentially a fork of an earlier operating system originating on the MIT AI Lab's Lisp machines which Symbolics had used in common with LMI and Texas Instruments...
—boomslangs, twig snakes,
keelback snakeRhabdophis is a genus of snakes, generally called Keelback snakes, found primarily in southeast Asia.- Species of Rhabdophis :* Rhabdophis adleri* Rhabdophis angeli* Rhabdophis auriculata...
s,
green snakePhilodryas is a genus of New World colubrid snakes, usually named green snakes. Although colubrid snakes are usually harmless to humans, Philodryas are opisthoglyphous snakes and can give a venomous bite....
s, and
slender snakeTachymenis is a genus of venomous snakes belonging to the family Colubridae. They are commonly known as slender snakes or short-tailed snakes and are primarily found in southern South America. Tachymenis are capable of producing a medically significant bite, with at least one species, T...
s—have caused human fatalities.
Since reporting is not mandatory in many regions of the world, snakebites often go unreported. Consequently, no accurate study has ever been conducted to determine the frequency of snakebites on the international level. However, some estimates put the number at 5.4 million snakebites, 2.5 million envenomings, resulting in perhaps 125,000 deaths. Others estimate 1.2 to 5.5 million snakebites, 421,000 to 1.8 million envenomings, and 20,000 to 94,000 deaths. Many people who survive bites nevertheless suffer from permanent tissue damage caused by venom, leading to disability.
Most snake envenomings and fatalities occur in
South AsiaSouth Asia, also known as Southern Asia, is the southern region of the Asian continent, which comprises the sub-Himalayan countries and, for some authorities , also includes the adjoining countries on the west and the east...
,
Southeast AsiaManila
Bangkok
Ho Chi Minh City
Kuala Lumpur
Singapore
Yangon
Bandung
Hanoi
Surabaya
Taichung
Kaohsiung
Medan|-|}...
, and
sub-Saharan AfricaSub-Saharan Africa is a geographical term used to describe the area of the African continent which lies south of the Sahara, or those African countries which are fully or partially located south of the Sahara...
, with
IndiaIndia, officially the Republic of India , is a country in South Asia. It is the seventh-largest country by geographical area, the second-most populous country, and the most populous democracy in the world. Bounded by the Indian Ocean on the south, the Arabian Sea on the west, and the Bay of Bengal...
reporting the most snakebite deaths of any country. Almost all of these deaths are caused by the
Big FourThe Big Four are the venomous snake species considered to be South Asia's most famous.The Big Four are:* Indian cobra, Naja naja, probably the most famous of all Indian snakes.* Common krait, Bungarus caeruleus...
, consisting of the Russell's viper,
Indian cobraNaja naja is a species of venomous snake native to the Indian subcontinent which includes present day Pakistan, India, Bangladesh and Sri lanka. It is the most famous of the Big Four, the four most venomous snakes of India for which a single polyvalent antivenom has been created. Like other...
, saw-scaled viper, and the
common kraitThe Common Krait is a type of krait that is found in the jungles of the Indian sub-continent. This snake is highly venomous, and is one of the "big four" snakes in India.-Description:...
. In the Neotropics, the
lance-headed vipersBothrops is a genus of venomous pitvipers found in Central and South America. The generic name is derived from the Greek words bothros and ops that mean "pit" and "eye" or "face"; an allusion to the heat-sensitive loreal pit organs. Members of this genus are responsible for more human deaths in the...
inflict the majority of fatal bites, although of the many known species, only two, the
common lanceheadBothrops atrox is a venomous pitviper species found in tropical lowlands of northern South America east of the Andes. No subspecies are currently recognized. This species is very dangerous and is the cause of more human fatalities than any other American reptile.-Description: A terrestrial species,...
and
terciopeloBothrops asper is a venomous pitviper species found in Central and northern South America. Sometimes referred to as the "ultimate pitviper," these snakes are found in a wide range of lowland habitats, often near human habitations. Large and nervous, this species is the main cause of snakebite...
, are responsible for most cases. The tropical rattlesnake is another important species.
In Africa, the
puff adderBitis arietans is a venomous viper species found in savannah and grasslands from Morocco and western Arabia throughout Africa except for the Sahara and rain forest regions. Its wide distribution, common occurrence, large size, potent venom, and willingness to bite make it responsible for more...
is responsible for most fatalities, although there are regional differences, with the saw-scaled viper inflicting more bites in Northern Africa, where the puff adder is not normally found. Most bites occur in industrial plantations, which attract many types of snake prey. Banana plantations are associated with vipers such as
night adderThe Causinae are a monotypic subfamily of venomous vipers found only in subsaharan Africa. It was created for the genus Causus; a group considered to be among the most primitive members of the family Viperidae based on head scalation, oviparity, venom apparatus and the fact that they have round...
s, while rubber and palm tree plantations attract elapids, including cobras and
green mambaGreen mamba may refer to:* Eastern green mamba* Western green mamba...
s. There are also highly venomous colubrids in Africa, such as the boomslang.
In the Middle East, the snakes responsible for most bites tend to be more venomous than European species, but deaths are rare, with some estimating perhaps 100 fatal bites annually. The
coastal viperVipera xanthina is a venomous viper species found in northeastern Greece and Turkey, as well as certain islands in the Aegean Sea. No subspecies are currently recognized.-Description:...
, Palestine viper, and Lebetine viper are the species involved in most bites. Larger and more venomous elapids, such as the
Egyptian cobraThe Egyptian cobra is a venomous snake found in Africa and the Arabian Peninsula.- Description :The Egyptian cobra may grow to 5'-6'8" in length and specimens as long as 8' have been seen in some areas. The most recognizable characteristics of an Egyptian cobra are its head and hood. The head is...
, can also be found throughout the Middle East.
In Europe, nearly all of the snakes responsible for venomous bites belong to the viper family, and of these, the
nose-horned viperVipera ammodytes is a venomous viper species found in southern Europe through to the Balkans and parts of the Middle East. It is reputed to be the most dangerous of the European vipers due to its large size, long fangs and high venom toxicity...
,
asp viperVipera aspis is a venomous viper species found in southwestern Europe. Bites from this species can be more severe than from the European adder, V. berus; not only can they be very painful, but according to Stemmler , about 4% of all untreated bites are fatal...
, and Lataste's viper inflict the majority of bites. Although Europe has a population of some 731 million people, snake bites only kill about 30 people each year, largely due to wide access to health care services and antivenom, as well as the relatively mild potency of many native species' venom.
In Australia, the only continent where venomous snakes constitute the majority of species, the kraits, tiger snake and Eastern brown snake inflict virtually all reported venomous bites, with the latter responsible for perhaps 60% of deaths caused by snakebite. Although Australian snakes are among the most venomous in the world, wide access to antivenom has made deaths exceedingly rare, with only a few fatalities each year.
Most of the
Pacific IslandsThe Pacific Islands comprise 20,000 to 30,000 islands in the Pacific Ocean. Those islands lying south of the tropic of Cancer are traditionally grouped into three divisions: Melanesia, Micronesia and Polynesia.-Oceania:...
are free of terrestrial snakes; however,
sea snakesSea Snakes were a Canadian indie rock band, formed in 2002 and disbanded in 2005. The band consisted of vocalist and guitarist Jimmy McIntyre, guitarist Kristian Galberg, bassist and saxophonist Jeremy Strachan, keyboardist Shaw-Han Liem and drummer Nathan Lawr.Strachan played in the defunct band...
are common in the
Indian OceanThe Indian Ocean is the third largest of the world's oceanic divisions, covering about 20% of the water on the Earth's surface. It is bounded on the north by South Asia ; on the west by Africa; on the east by Indochina, the Sunda Islands, and Australia; and on the south by the Southern Ocean...
and tropical
Pacific OceanThe Pacific Ocean is the largest of the Earth's oceanic divisions. Its name is derived from the Latin name Tepre Pacificum, "peaceful sea", bestowed upon it by the Portuguese explorer Ferdinand Magellan. It extends from the Arctic in the north to Antarctica in the south, bounded by Asia and...
, but are not found in the
Atlantic OceanThe Atlantic Ocean is the second-largest of the world's oceanic divisions. With a total area of about 106.4 million square kilometres , it covers approximately one-fifth of the Earth's surface and about one-quarter of its water surface area. The first part of its name refers to the Atlas of Greek...
or the
CaribbeanThe Caribbean Sea is a sea of the Atlantic Ocean situated in the tropics of the Western hemisphere, bounded to the south and west by the American landmass, with the North Atlantic Ocean proper to the northeast and the Gulf of Mexico to the northwest...
,
MediterraneanThe Mediterranean Sea is a sea connected to the Atlantic Ocean surrounded by the Mediterranean region and almost completely enclosed by land: on the north by Anatolia and Europe, on the south by Africa, and on the east by the Levant. The sea is technically a part of the Atlantic Ocean, although it...
or
Red SeaThe Red Sea is a seawater inlet of the Indian Ocean, lying between Africa and Asia. The connection to the ocean is in the south through the Bab el Mandeb strait and the Gulf of Aden. In the north, there is the Sinai Peninsula, the Gulf of Aqaba, and the Gulf of Suez,...
s. While the majority of species live close to shorelines or
coral reefCoral reefs are aragonite structures produced by living organisms, found in marine waters containing few nutrients. In most reefs, the predominant organisms are stony corals, colonial cnidarians that secrete an exoskeleton of calcium carbonate...
s, the
yellow-bellied sea snakeYellowbelly Sea Snake or Pelagic Sea Snake is a species of sea snake found in tropical oceanic waters around the world.-Description:...
can be found in the open ocean. Over 50% of bites inflicted by sea snakes, which are generally not aggressive, occur when fisherman attempt to remove snakes which have become tangled in fishing nets. Symptoms may appear in as little as 5 minutes or take 8 hours to develop, depending on the species and region of the body bitten. Although sea snakes are highly venomous, about 80% of reported bites end up being dry. The advent of antivenom and advances in emergency medicine have reduced fatalities to about 3% of snakebite cases.
Of the 120 known indigenous snake species in North America, only 20 are venomous to human beings, all belonging to the families
ViperidaeThe Viperidae are a family of venomous snakes found all over the world, except in Antarctica, Australia, New Zealand, Ireland, Madagascar, Hawaii and the Arctic Circle. All have relatively long hinged fangs that permit deep penetration and injection of venom...
and
ElapidaeThe Elapidae, or elapids, are a family of venomous snakes found in tropical and subtropical regions around the world, including the Indian Ocean and the Pacific. Elapid comes from the Greek éllops meaning sea-fish...
. However, in the
United StatesThe United States of America is a federal constitutional republic comprising fifty states and a federal district...
, every state except
MaineThe State of Maine is a state in the New England region of the northeastern United States, bordering the Atlantic Ocean to the southeast, New Hampshire to the southwest, and the Canadian provinces of Quebec to the northwest and New Brunswick to the northeast. Maine is the northernmost portion of...
,
AlaskaAlaska is the largest state of the United States of America by area; it is situated in the northwest extremity of the North American continent, with Canada to the east, the Arctic Ocean to the north, and the Pacific Ocean to the west and south, with Russia further west across the Bering Strait...
, and
HawaiiHawaii is the newest of the 50 U.S. states, and is the only state made up entirely of islands. It is located on an archipelago in the central Pacific Ocean, southwest of the continental United States, southeast of Japan, and northeast of Australia. The state was admitted to the Union on August...
is home to at least one of 20 venomous snake species. Most snakebite related deaths in the United States are attributed to
EasternCrotalus adamanteus is a venomous pitviper species found in the southeastern United States. It is the heaviest venomous snake in the Americas and the largest rattlesnake. No subspecies are currently recognized.-Description:...
and
Western diamondbackCrotalus atrox is a venomous pitviper species found in the United States and Mexico. It is likely responsible for the majority of snakebite fatalities in northern Mexico and the second greatest number in the USA after C. adamanteus. No subspecies are currently recognized.-Description: Adults...
rattlesnake bites. Further, the majority of bites in the United States occur in the southwestern part of the country, in part because
rattlesnakeRattlesnakes are a group of venomous snakes, genera Crotalus and Sistrurus. They belong to the subfamily of venomous snakes known commonly as pit vipers.-Overview:...
populations in the eastern states are much lower. The state of
North CarolinaNorth Carolina is a state located on the Atlantic Seaboard in the southeastern United States. The state borders South Carolina and Georgia to the south, Tennessee to the west and Virginia to the north. North Carolina contains 100 counties...
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.
Worldwide, snakebites occur most frequently in the summer season when snakes are active and humans are outdoors. Agricultural and tropical regions report more snakebites than anywhere else. Victims are typically male and between 17 and 27 years of age. Children and the elderly are most likely to die.
Snakebites in human culture
Snakes were both
revered and worshippedThe worship of serpent deities is present in several old cultures, particularly in religion and mythology, where snakes were seen as entities of strength and renewal.-Hindu mythology:...
and
fearedOphidiophobia or ophiophobia refers to the fear of snakes. Fear of snakes is sometimes called by a more general term, herpetophobia, fear of reptiles. It is one of the most common zoophobias . Care must also be taken to differentiate people who do not like snakes or fear them for their venom or...
by early civilizations. The ancient Egyptians recorded prescribed treatments for snakebites as early as the
Thirteenth dynastyThe Eleventh , Twelfth, Thirteenth and Fourteenth Dynasties of ancient Egypt are often combined under the group title, Middle Kingdom. Other writers separate it from these dynasties and join it to the Fourteenth through Seventeenth Dynasties as part of the Second Intermediate Period...
in the
Brooklyn PapyrusThe Brooklyn Papyrus, otherwise known as the Brooklyn Medical Papyrus, is an ancient Egyptian medical papyrus believed to have been created during the thirtieth dynasty of Egypt. The papyrus describes ailments for poisons derived from snakes, scorpions and tarantulas. Currently residing in the...
, which includes at least seven venomous species common to the region today, such as the
horned viperCerastes is a genus of small, venomous vipers found in the deserts and semi-deserts of northern North Africa eastward through Arabia and Iran. Three species are currently recognized.- Description :...
s. In
JudaismJudaism is a set of beliefs and practices originating in the Hebrew Bible , as later further explored and explained in the Talmud and other texts...
, the
NehushtanThe Nehushtan , in Judaism, was a sacred object in the form of a copper snake upon a pole. King Hezekiah instituted a religious iconoclastic reform and destroyed the Nehushtan...
was a pole with a snake made of copper wrapped around it, similar in appearance to the
Rod of Asclepius__FORCETOC__ The rod of Asclepius , also known as the asklepian, is an ancient symbol associated with astrology, the Greek god Asclepius and with healing. It consists of a serpent entwined around a staff...
. The object was considered sacred with the power to heal bites caused by the snakes which had infested the desert, with victims merely having to touch it in order to save themselves from imminent death.
Historically, snakebites were seen as a means of execution in some cultures. In
medieval EuropeThe Middle Ages of European history is a period of European history covering roughly a millennium in the 5th century through 16th centuries. More specific starting and ending points are sometimes adopted by scholars to suit their respective specializations or current focus...
, a form of capital punishment was to throw people into
snake pitSnake pits were a historical European means of imposing capital punishment. Convicts were cast into a deep pit containing venomous snakes, such as vipers. They died from snake venom poisoning as the irritated snakes attacked them...
s, leaving victims to die from multiple venomous bites. A similar form of punishment was common in
Southern HanSouthern Han was a kingdom that existed during the Five Dynasties and Ten Kingdoms Period along China’s southern coast from 917 to 971. The Kingdom greatly expanded her capital city Hing Wong Fu , namely present-day Guangzhou...
during
ChinaChina is a cultural region, an ancient civilization, and, depending on perspective, a national or multinational entity extending over a large area in East Asia....
's
Five Dynasties and Ten Kingdoms PeriodFive Dynasties and Ten Kingdoms was an era of political upheaval in China, beginning in the Tang Dynasty and ending in the Song Dynasty. During this period, five dynasties quickly succeeded one another in the north, and more than 12 independent states were established, mainly in the south...
and in
IndiaIndia, officially the Republic of India , is a country in South Asia. It is the seventh-largest country by geographical area, the second-most populous country, and the most populous democracy in the world. Bounded by the Indian Ocean on the south, the Arabian Sea on the west, and the Bay of Bengal...
. Snakebites were also used as a form of suicide, most notably by Egyptian queen Cleopatra VII, who reportedly died from the bite of an
aspAsp is the modern Anglicisation of the word aspis, which in antiquity referred to any one of several venomous snake species found in the Nile region. It is believed that the aspis referred to in Egyptian mythology is the modern Egyptian cobra....
—likely an
Egyptian cobraThe Egyptian cobra is a venomous snake found in Africa and the Arabian Peninsula.- Description :The Egyptian cobra may grow to 5'-6'8" in length and specimens as long as 8' have been seen in some areas. The most recognizable characteristics of an Egyptian cobra are its head and hood. The head is...
—after hearing of
Mark AntonyMarcus Antonius , known in English as Mark Antony, was a Roman politician and General. He was an important supporter and the loyal friend of Gaius Julius Caesar as a military commander and administrator, being Caesar's second cousin, once removed, by his mother Julia Antonia...
's death.
Snakebite as a surreptitious form of murder has been featured in stories such as Sir
Arthur Conan DoyleSir Arthur Ignatius Conan Doyle,
DL was a British physician and writer, most noted for his stories about the detective Sherlock Holmes, which are generally considered a major innovation in the field of crime fiction, and for the adventures of Professor Challenger...
's
The Adventure of the Speckled Band"The Adventure of the Speckled Band" is one of the 56 short Sherlock Holmes stories written by Scottish author Sir Arthur Conan Doyle. It is the eighth of the twelve stories collected in The Adventures of Sherlock Holmes. The story was first published in Strand Magazine in February 1892, with...
, but actual occurrences are virtually unheard of, with only a few documented cases. It has been suggested that
Boris III of BulgariaBoris III the Unifier, Tsar of Bulgaria , originally Boris Klemens Robert Maria Pius Ludwig Stanislaus Xaver , son of Ferdinand I, came to the throne in 1918 upon the abdication of his father, following the defeat of the Kingdom of Bulgaria during World War I...
, who was allied to
Nazi GermanyNazi Germany and the Third Reich are the common English names for Germany between 1933 and 1945, while it was led by Adolf Hitler and the National Socialist German Worker's Party . The name Third Reich refers to the state as the successor to the Holy Roman Empire of the Middle Ages and the German...
during
World War IIWorld War II, or the Second World War , was a global military conflict which involved a majority of the world's nations, including all great powers, organized into two opposing military alliances: the Allies and the Axis...
, may have been killed with snake venom, although there is no definitive evidence. At least one attempted suicide by snakebite has been documented in medical literature involving a
puff adderBitis arietans is a venomous viper species found in savannah and grasslands from Morocco and western Arabia throughout Africa except for the Sahara and rain forest regions. Its wide distribution, common occurrence, large size, potent venom, and willingness to bite make it responsible for more...
bite to the hand.
See also
- Snake
Snakes are elongate legless carnivorous reptiles of the suborder Serpentes that can be distinguished from legless lizards by their lack of eyelids and external ears. Like all squamates, snakes are ectothermic amniote vertebrates covered in overlapping scales...
- Venomous snakes
- Snake venom
Snake venom is highly modified saliva that is produced by special glands of certain species of snakes. The gland which secretes the zootoxin is a modification of the parotid salivary gland of other vertebrates, and is usually situated on each side of the head below and behind the eye, invested in...
- Antivenom
- Snake-stones
Snake-stones also known as the viper's stone, black stone, the black stone, der schwarze Stein, la pierre noire, and la piedrita negra or serpent-stone are animal bones, which are widely used and promotedas a treatment for snake bite in Africa, South America and Asia...
- Ophidiophobia
Ophidiophobia or ophiophobia refers to the fear of snakes. Fear of snakes is sometimes called by a more general term, herpetophobia, fear of reptiles. It is one of the most common zoophobias . Care must also be taken to differentiate people who do not like snakes or fear them for their venom or...
- Medical emergency
A medical emergency is an injury or illness that is acute and poses an immediate risk to a person's life or long term health. These emergencies may require assistance from another person, who should ideally be suitably qualified to do so, although some of these emergencies can be dealt with by the...
- Wilderness first aid
Wilderness first aid is the specific discipline of First aid which relates to care in remote areas, where emergency medical services will be difficult to obtain or will take a long time to arrive. Nursing care, though not part of normal first aid, is part of wilderness first aid.Training in...
- Wilderness emergency medical technician
Wilderness Emergency Medical Technician, or WEMT, is the second highest level of wilderness emergency medical training available in the USA , or other courses for advanced providers such as AWLS, and RMAP...