SNAKE GENERAL DESCRIPTION
A snake is a reptile, and like all reptiles, snakes are ectothermic, or cold blooded, and covered in scales. They are distinguished from legless lizards by their lack of eyelids, limbs, and external ears. The 2,900 species of snakes spread across every continent except Antarctica and range in size from the tiny, 4-inch-long thread snake, to pythons and anacondas over 23 feet long.
Venomous snakes comprise a minority of the species of snakes. A snake's venom is primarily for killing and subduing prey rather than for self-defense.
All snakes are carnivorous. They eat small animals including lizards, other snakes, small mammals, birds, eggs, fish, snails or insects. They use smell to track their prey, and are very sensitive to vibration, thus a snake is able to sense other animals approaching through detecting faint vibrations in the air and on the ground.
Snakes do not bite or tear their food to pieces. Instead they swallow their prey whole. The body size of a snake influences its eating habits. Smaller snakes eat smaller prey, adult pythons, on the other hand, are able to eat small deer or antelope.
The snake's jaw is the most unique jaw in the animal kingdom. It behaves like a hinge, opening up to 180°. A snake's chin, which is detached in the middle, spreads apart to accommodate its prey.
Once they have eaten, snakes become torpid while the process of digestion takes place. Digestion is an intense activity for snakes, and requires a large amount of metabolic energy. Due to this heightened state of digestion, if a snake is disturbed after recently eating, it will often regurgitate its prey in order to have the ability to escape the perceived threat. When undisturbed, the digestive process is highly efficient, dissolving and absorbing everything but hair, teeth, and claws.
The skin of a snake is covered in scales and has a smooth, dry texture. Most snakes use specialized belly scales to travel and grip surfaces. A snake's eyes are covered by transparent "spectacle" scales.
The shedding of scales is called moulting or sloughing. Snake scales are extensions of their skin. They are not shed separately, but are removed as one complete outer layer of skin during each moult, much like a sock being turned inside out.
Moulting is repeated periodically throughout a snake's life and serves two major functions for snakes: the old and worn skin is replaced, and it helps get rid of parasites such as mites and ticks.
Poisonous snakes are found throughout the world, primarily in the tropical and temperate regions. Within the United States, there are 20 species of poisonous snakes. There are four types and they can be grouped into two families, the Crotalidae (a variety of rattlesnakes, copperheads, and water moccasins [cottonmouths]), and the Elapidae (coral snakes).
Approximately 9,000 Americans are bitten by poisonous snakes each year, most commonly in the summer months, in grassy or rocky environments. However, only about 25 percent of these bites involve venom - that is, the snake saves its venom for its prey, not necessarily for defense. If you encounter a snake that is large enough to consider you prey, your problems far outweigh a simple bite!
The toxicity of snake venom, which varies from species to species, can kill local tissue and release toxins into the body that can cause serious problems with blood pressure, heart rate, and pain. A person who has been bitten by a poisonous snake may exhibit mild to severe symptoms, which can include swelling, or discoloration of the skin in the area of the bite, a racing pulse, weakness, shortness of breath, nausea and vomiting. In extreme cases, pain and swelling can be severe, the pupils may dilate, and shock and convulsion may occur. The person may twitch and his or her speech may become slurred. In the most severe cases, paralysis, unconsciousness, and death can result. There are only about 8 or 9 deaths in the United States each year due to snakebite, yet this is a situation feared universally by hikers, paddlers, climbers, fishermen, hunters, and campers. Most deaths occur in children because of their smaller body mass and lack of sufficient immune system development. Improper treatment causes many injuries, and there is a lot of conflicting information and misinformation concerning first-aid (see General First Aid For Snakebites for more information).
It is worth emphasizing that the majority of snakes are not poisonous. Nevertheless, anyone who has been bitten by a snake should be seen by a medical professional immediately, because the severity of initial symptoms does not always reflect the seriousness of the bite.
Snakes like to live in damp, dark, cool places where food is abundant. Likely places around homes to find snakes include:
- Firewood stacked directly on the ground.
- Old lumber or junk piles.
- Gardens and flower beds with heavy mulch.
- Untrimmed shrubs and shrubs growing next to a foundation.
- Unmowed and unkept lawns, abandoned lots, and fields with tall vegetation.
- Pond and stream banks where there is abundant debris or trash.
- Cluttered basements and attics with a rodent, bird, or bat problem.
- Feed storage areas in barn hay lofts where rodents may be abundant.
Some poisonous snakes have more specialized habitat requirements.
- Cottonmouths are confined to a few choice wetlands and swamps in the south central-southeast region of the U.S. Cottonmouths may be common in these swamps, but the number of swamps where they can be found is declining because wetlands are being converted into agricultural fields.
- Pygmy rattlesnakes are small snakes that are sometimes encountered when they cross gravel roads in the evening. Their range is restricted almost entirely to the Land Between the Lakes region in Kentucky.
- Rattlesnakes prefer sparsely populated forested areas where there are numerous rock outcroppings, rocky slopes, and boulders. At one time, timber rattlesnakes were common throughout the southeast region. Because humans have disturbed much of this snake's habitat, timber rattlesnakes are becoming uncommon throughout this area and do not occur in the inner Bluegrass region. Killing a rattlesnake is now an unusual occurrence and is considered front-page news in local newspapers.
- Copperheads are the most abundant venomous snakes found in Kentucky. They can be found throughout the commonwealth but are rare to absent in the inner Bluegrass region. Copperheads prefer to live in hilly forested areas with rocky bluffs and ravines. They can also be found along wooded stream borders, old fields, and meadows where they search for rodents.
POISONOUS VS NON-POISONOUS
Because the majority of poisonous snakes in the United States are members of the pit viper family, you can easily tell the difference between poisonous and harmless snakes. The three ways to distinguish poisonous snakes:
- Pupil Shape: The black part in the center of the eye (pupil) of harmless snakes is round. Poisonous snakes have egg-shaped or cat-like (elliptical) pupils. In good light, you can easily see the pupil shape from a safe distance because snakes cannot jump nor can they strike from more than one-third of their body length.
- Pit: Poisonous snakes also have a very conspicuous sensory area or pit (hence the name "pit viper") on each side of the head. The pit looks somewhat like a nostril and helps the snake locate warm-bodied food. It is located about midway and slightly below the eye and nostril. Harmless snakes do not have pits.
- Scale Arrangement: The underside scales of a venomous snake's tail go all the way across in a single row from the anal plate. The very tip of the tail may have two scale rows. Non-poisonous snakes have two rows of scales from the vent to the end of the tail. This characteristic can also be observed on skins that have been shed.
Other features that may help you identify a poisonous snake at a distance:
- Head Shape: Venomous snakes usually have a triangular (wide at the back and attached to a narrow neck) or "spade-shaped" head. Be aware that many harmless snakes flatten their heads when threatened and may appear poisonous.
- Distinctive Sound: Rattlesnakes will usually sound a warning rattle (a buzz or a dry, whirring sound) when approached. However, many non-poisonous snakes (black racers, corn snakes, rat snakes, milk snakes, and pine snakes) and several poisonous snakes (copperhead and cottonmouth) often vibrate their tails when threatened. The sound produced by this vibration often imitates a rattle or hissing sound when the snake is sitting in dry grass or leaves.
- Tail: You can easily recognize young cottonmouths and copperheads by their bright yellow or greenish yellow tail.
GENERAL POISONOUS SNAKEBITE SYMPTOMS
It is essential that you be able to quickly diagnose a snakebite as being envenomated or not. Normally enough symptoms present within an hour of a poisonous snakebite to eliminate any doubt. The casualty's condition provides the best information as to the seriousness of the situation. The bite of the pit viper is extremely painful and is characterized by immediate swelling around the fang marks, usually within 5 to 10 minutes, spreading and possibly involving the whole extremity within an hour. If only minimal swelling occurs within 30 minutes, the bite will almost certainly have been from a non-poisonous snake, or from a poisonous snake that did not inject venom. When the venom is absorbed, there is a general discoloration of the skin, followed by blisters and numbness in the affected area. Other signs that may occur:
- Rapid pulse.
- Shortness of breath.
- Blurred vision.
The eastern diamond back rattler bite is further characterized by:
- Numbness and tingling in the mouth, possibly the face and scalp.
- A metallic taste may be noted.
Snake venoms can be classified as hemotoxic (attacking tissue and blood) and neurotoxic (damaging or destroying nerve tissue). Pit viper snake venoms are hemotoxic, except for some Mojave rattlers. Contrary to public perception, pit viper bites are not immediately fatal unless the venom enters a vein directly. The venom consists of proteins, polypeptides, and enzymes that cause necrosis and hemolysis. Most crotalid venoms damage capillary endothelial cells, resulting in third spacing of plasma and extravasation of erythrocytes.
Pit viper bites classically appear as two fang punctures (one or three puncture wounds occur, but rarely) with local swelling and necrosis. Extremity bites are rarely complicated by infection and compartment syndrome, and prophylactic fasciotomies often do more harm than good.
Because of their widespread distribution and relatively potent venom, rattlesnakes are responsible for most fatalities from snakebites in the United States.
Clinical effects of snakebites range from mild local reactions to life-threatening systemic reactions, depending on the species and size of the snake involved; the location of the bite(s); the volume of venom injected; and the age, size, and health of the victim. Children are more likely to suffer significant morbidity and mortality because they receive a larger envenomation relative to body size.
Most pit viper bites are painful within five minutes and soon display local swelling. Symptoms of hemotoxic envenomation are listed in the following table. Significant hypofibrinogenemia and thrombocytopenia lasting up to two weeks may occur after envenomation by North American pit vipers.
Systemic reactions include a syndrome similar to disseminated intravascular coagulation, acute renal failure, hypovolemic shock, and death. Renal failure is a common cause of delayed mortality from untreated snakebites in developing parts of the world. Immediately life-threatening conditions such as hypotension or shock occur in only about 7 percent of envenomations.
The venoms of coral snakes, exotic elapids and some Mojave rattlesnakes are neurotoxic and usually cause local numbness instead of pain and swelling, with the risk of cranial nerve palsies, respiratory paralysis, and death. Systemic reactions are difficult to reverse once they develop.
SYMPTOMS OF SNAKEBITE ENVENOMATION
HEMOTOXIC SYMPTOMS NEUROTOXIC SYMPTOMS Intense pain. Edema. Weakness. Swelling. Numbness or tingling. Rapid pulse. Ecchymoses (bruising). Muscle fasciculation (twitching). Paresthesia (oral) (numbness, burning, tingling). Unusual metallic taste. Vomiting. Confusion. Bleeding disorders. Minimal pain. Ptosis (drooping eye lid). Weakness. Paresthesia (often numb at bite site). Diplopia (double vision). Dysphagia (swallowing diffulty). Sweating. Salivation. Diaphoresis (profuse sweating). Hyporeflexia (decreased reflexes). Respiratory depression. Paralysis.
Many people are surprised to find that in about 25 percent of pit viper bites and nearly 50 percent of coral snakebites absolutely no venom is injected. This is not a feature limited to U.S. snakes. The same occurs for venomous snakes throughout the world. These bites are termed dry bites, and cause no problems other than fang marks. Dry bites can occur because the snake's venom glands are surrounded by voluntary muscles that control the amount of venom injected in each bite. The snake actually varies the amount of venom injected in relation to the size of the prey and the purpose of the bite: for feeding or for defense. Research has shown that rattlesnakes inject significantly more venom into larger mice than into smaller mice. It is possible that a person even may have multiple fang marks from several bites without envenomation. Thus, an asymptomatic patient presenting with the history of a venomous snakebite may require a period of observation (at least 8 hours) to see if envenomation has occurred or not. Two notable exceptions are young children or patients bitten by a Mojave rattlesnake, where both should be observed for 24 hours.
RELATED MOONDRAGON'S LINKS
MoonDragon's Health & Wellness: Insect Bites
MoonDragon's Health & Wellness: Spider Bites
MoonDragon's Health & Wellness: Scorpion Sting
NON-VENOMOUS SNAKE DESCRIPTIONS
By nature, non-venomous snakebites normally are not clinically significant. North American non-venomous snakes are constrictors (i.e., corn snakes, king snakes) or snakes that eat their prey live (i.e., garter snakes). Their teeth are very small and curved in toward their throats, and function to keep prey from escaping once captured. Bite wounds consist of several very small, needle-like puncture wounds, sometimes in parallel rows if both sides of the jaw connect with the patient. These patients most often present to the emergency department (ED) because they are not sure if the snake that bit them was venomous or not. Most of their care centers on identification of the snake, and once assured it was not venomous, reassurance that no harm will come to them. Prophylactic antibiotics are not indicated, and bite wounds require no special treatment. As with all other bites and stings, tetanus prophylaxis is recommended if not already up to date.
The only exception to the above discussion would be large constrictors, such as boas or pythons, that are not native to the United States. Although not native, there are a great many of these snakes in captivity as pets in the United States. Most major U.S. cities have reptile shows yearly where these animals can be purchased for as little as $10. Boa constrictors, ball pythons, and Burmese pythons are three of the most popular examples. While all three are similar in size as hatchlings, ball pythons only reach 4-5 feet in length and weigh a few pounds.
In contrast, boas can grow to be 10 feet and 40-50 pounds, and Burmese pythons easily can reach 12-18 feet and more than 150 pounds as adults. Further, when properly fed, these animals can reach these lengths in as few as 2-3 years. Well-fed large snakes can be quite docile depending on the species.
Boa constrictors and Burmese pythons are well known for their docile dispositions, while reticulated pythons tend to be more aggressive. Still, as with all animals, the behavior of individuals can vary. Some owners mistakenly believe that withholding food or keeping larger species in small cages will stunt their growth enough to keep them from getting large. While spacing out feedings will make these snakes grow more slowly, they also will be quite hungry all of the time, making them mean and unpredictable. Snakes treated this way are much more likely to strike at anything warm, as they might behave in the wild under stress. If uninformed or given bad advice, it is easy to unintentionally purchase an animal that quickly grows faster than one's ability to care for it. While many snake owners are well informed and conscientious, some purchase these large snakes without adequate knowledge of how to care for them. Each year in the United States, several people are attacked by their pets, and deaths are not unusual. Most attacks occur through inappropriate feeding where snakes are hand-fed or handled while the scent of prey is still on a patient's hands. These snakes hunt primarily by smell, and mistakenly may grab a hand when it smells like a mouse, rat, rabbit, chicken, or other prey. Although their mouths and teeth are designed the same as their North American counterparts, their large size makes their bites much more significant. The head of a large adult constrictor can be 6 inches across. Large lacerations can result, even injuring deep structures like tendons, nerves, and arteries. Unlike smaller snakes, bites from larger constrictors may need X-rays to evaluate for retained tooth fragments. Few studies exist, but they support that these bite wounds do not benefit from prophylactic antibiotics.
VENOMOUS SNAKE DESCRIPTIONS
Of the nearly 200 snake species native to North America, only a handful are venomous (28 pit vipers and two coral snakes). Be aware that only Maine, Alaska, and Hawaii have no native pit viper species. If dealing with an exotic snake species, identification can be much harder.
Three of the four groups of venomous snakes native to North America (i.e., rattlesnakes, cottonmouths, and copperheads) are pit vipers (Crotalidae). The only exceptions are the three brightly colored coral snake species (Elapidae family).
Pit vipers are named for the heat-sensing pit located between the eye and the nostril on each side of the head. The pit allows the snake to "see" in infrared and locate warm-blooded prey more efficiently in the dark. All pit vipers have pits 100 percent of the time, but if the head is damaged they may not be visible. Pits look like enlarged nostrils, and so require a relatively close look to be identified. Besides coral snakes, be aware that non-native vipers (vipers from Europe, Asia, and Africa) have no pits.
North American pit vipers also have elliptically shaped pupils similar to a cat's eyes, whereas non-venomous snakes have round pupils. Again, coral snakes are the exception, as they have round pupils. Assessing pupil shape also requires close proximity to the snake's head, which is not advisable with a live snake. Similarly, the numbering of the belly scales on the tail accurately can identify a venomous pit viper. Non-venomous snakes have a double row of scales below the anal plate, while venomous snakes have a single row. Once again, the coral snake remains the exception as a venomous snake with a double row of belly scales on the tail. And once again, belly scale patterns are a useful tool that requires closer contact than is recommended with a live snake.
Lastly, a warning that some methods of identification can be misleading. Head shape can be used to identify venomous snakes, as all pit vipers have triangular-shaped heads while non-venomous snakes have a streamlined shape. This is not recommended as an identification tool for the novice as many live non-venomous snakes flatten their heads when threatened and effectively make themselves look like venomous snakes. In addition, coral snakes are again the exception as their head shape is identical to non-venomous snakes. Likewise, coloring or the pattern on the snake can identify the species of the snake, but the novice should not use this as definitive identification alone. Color patterns change greatly with age of the snake, time of the year, and geographical location. A young snake typically looks quite different than it will as an adult, and considerable overlap in appearance of venomous and non-venomous snakes at various stages of their lives can exist. The same species from different states also may look at first like a different snake. In addition, many mimics of the coral snake exist that can be difficult to distinguish at first glance, thus coloring alone is not reliable. All venomous snakes have fangs, but while fangs can be large (1 to 1-1/2 inches) in pit vipers, they retract into fleshy coverings, and the snake voluntarily can keep one or both retracted when opening its mouth. Thus, absence of notable fangs when the snake opens its mouth may not be a sign of a non-venomous animal. Further, coral snakes have relatively small fangs that may not be seen easily even with close inspection. Snakes also naturally lose fangs over their lifetime, and even absence of fangs in a dead specimen may be only a sign of recent trauma.
Venomous Snakes. U.S. residents are relatively lucky compared to a large portion of the world when it comes to venomous snakes. The 2002 American Association of Poison Control Centers (AAPCC) report showed only two deaths for the 2325 venomous snakebites reported in the United States. The AAPCC numbers are an underestimate of the true number of venomous snakebites in the United States, estimated at 8000 per year. Still, this compares to an estimated 2.5 million venomous snakebites and 125,000 deaths worldwide, and actual numbers may be even larger. The majority of these deaths occur from lack of treatment resources, and the fact that many of these non-North American snakes tend to be more deadly than North American ones. Risk factors for venomous snakebite in the United States include male sex, younger age (17-27 years), and alcohol use as a significant co-factor. More than 95 percent of bites occur on the extremities, with bites peaking in months of July and August.
The only general rule here is to consult an expert, such as herpetologist at a local zoo or a toxicologist. There is now a national toll-free number (800-222-1222) that automatically connects to the nearest poison control center that may be helpful. The Arizona Poison and Drug Information Center (520-626-6016) also is a good back-up resource for venomous snakebite treatment, and maintains a database on antivenom availability in the United States.
Identification of North American snakes as venomous vs. non-venomous generally can be done using several anatomic features of venomous snakes; however, some caveats need to be made. Exceptions to these rules exist and will be listed. Identification often requires rather close examination of the snake, and one must be aware that this can be risky in itself. Do not handle the snake if not trained in snake identification. Dangerous envenomations (even deaths) have been reported from reflexive bites of severed snake heads. Further, several snake species are known to play dead convincingly and may come back to life unexpectedly. When in doubt, leave the snake alone and treat the patient based on symptoms. Likewise, one should discourage retrieval of a snake to the Emergency Department for identification. The incorrect snake may be brought back, leading instead to false assumptions and improper treatment. This also is can produce additional snakebite victims for treatment in the emergency room.
The most obvious identifier of a venomous snake is the presence of rattles on its tail. No snakes other than rattlesnakes have this feature, but be aware that rattles may be missing entirely from previous trauma. Also, a hatchling rattlesnake only possesses a button on the end of the tail and does not develop its first rattle segment until its first shed (about 1-2 weeks of age). To make things even more complicated, one subspecies (Santa Catalina rattlesnake) actually has no rattles naturally (they possess the tail bud at birth, but subsequent rattle segments develop but do not attach to the tail). While rattles accurately identify rattlesnakes, cottonmouths (or water moccasins), copperheads, and coral snakes all are venomous but have no rattles. Further, most all North American non-venomous snakes, as well as copperheads and cottonmouths, tend to rattle their tails when disturbed. If done around dry leaves, they can produce a rattling sound that initially may be confused with a true rattlesnake. Obviously, this benefits the snake if it is misidentified by a predator as a more deadly animal. Other methods of identification include the shape of the eye, pattern of belly scales on the tail, and presence of heat-sensing pits on the face.
COMMON VENOMOUS SNAKES IN THE UNITED STATES RATTLESNAKES
Banded Rock Black-Tailed Canebrake Diamond Back (Eastern & Western) Massasauga (Eastern & Western) Mojave Mottled Rock Pacific (Northern & Southern) Pigmy (Southeastern & Western) Prairie Red Diamond Ridge-Nosed Sidewinder Speckled Tiger Timber Twin-Spotted COPPERHEADS
Broad-Banded Northern Osage Southern Trans-Pecos Cottonmouths Eastern Florida Western
Arizona Eastern Texas Western
RATTLESNAKES (PIT VIPERS)
The Crotalidae are called pit vipers because of the small, deep pits between the nostrils and the eyes. They have two long hollow fangs, which normally are folded against the roof of the mouth, but which can be extended by a swivel mechanism when they strike. Other identifying features include thick bodies, slit-like pupils of the eyes, and flat triangular heads. Further identification is provided by examining the wound for signs of fang entry in the bite pattern shown above. Individual identifying characteristics include audible rattles on the tails of most rattlesnakes and the cotton white interior of the mouths of moccasins.
Various rattlesnakes species are found only in the Western Hemisphere from SW Canada to Argentina. 32 species and 83 subspecies of rattlesnakes are identified in the Americas. Crotalus has 29 species and 74 subspecies. Sistrurus consists of 3 species and 9 subspecies. South America has 9 subspecies of rattlesnakes. Mexico and Central America have 4 subspecies. Rattlesnakes can be found in a range of habitats and mountain elevations up to 14,000 feet. The timber rattlesnake was once found in both Rhode Island and the southern Maine, but has been exterminated from both states. Alaska, Delaware, and Hawaii have no records of rattlesnakes. Every other state has at least 1 species of rattlesnake.
The Western Rattlesnake (Crotalus viridis) has one of the largest home ranges of rattlesnakes in North America. This rattlesnake or its subspecies can be found in the Canadian provinces and southward across the central United States to Mexico. In South Dakota, the subspecies is called the Prairie Rattlesnake (C. v. viridis) and found 10-15 miles east of the Missouri River and western South Dakota, in the open prairies, haylands, and croplands -- any area with an abundance of food.
The rattles and their distinctive rattling sound are the most recognizable feature of this snake . The Prairie Rattlesnake is the only venomous snake native to South Dakota. Young rattlesnakes are born with a prebutton, a rattle segment at the tip of their tail. All other South Dakota snakes are born with a pointed tail. Rattlesnakes (along with copperheads and cottonmouths) are members of the Pit Viper family. The "pit vipers" have a triangular shaped head with a small cavity or pit on each side, between the eye and the nostril. They can sense warm-blooded prey in complete darkness up to 2 feet away. These thermoreceptor organs contain nerves that are sensitive to heat or warmth and can detect temperature differences within several thousandths of a degree.
The color of the Prairie Rattlesnake varies from light brown to green, with a yellowish belly. Dark oval blotches with light colored borders run along the center of its back. The blotches become crossbands on the back part of the body and rings around the tail. Adults will range in length from 30-40 inches, with a record of 57 inches. Three foot rattlesnakes normally weigh 1 pound (a 54 inch snake weighed 4-1/2 pounds).
Many South Dakotans admit they have never seen a rattlesnake in the wild, even those in rattlesnake country. If they knew how many times they where within 10-15 feet of a snake, there would be many places they would never go back to. Snakes have a great display of camouflage. Most snakes are normally timid and secretive. When approached, they usually remain quiet to avoid detection. They may try to escape if given an opportunity. When frightened, cornered, or attacked, snakes will stand their ground and may attempt to strike at or bite their intruder.
There was an interesting article in the South Dakota Magazine (September/October 1991) "Rattlesnake Hunt at Mobridge". Several men went snake hunting on a prairie dog town on a warm fall afternoon. When the hunt was over, the men had killed over 400 rattlesnakes at this denning area. Most dens will average 250 snakes, but some dens have been reported to have up to 1,000 snakes of the different species, denning in the underground structure.
Rattlesnakes are cold-blooded or ectothermic animals. Their body temperature is influenced more by the temperature at the grounds surface where they are lying, rather than the air temperature. High or low temperatures cause the snakes to seek escape cover or shady areas. Most snakes cannot survive exposure to direct sunlight with temperatures over 100°F, but rattlesnakes have a greater endurance to lower or freezing temperatures. Lethal temperatures for the snakes depend on the time of exposure. Unlike warm-blooded or endothermic animals, snakes are unable to produce their own body heat. To maintain a desirable temperature, snakes must rely the temperature or warmth of their surroundings. The snake's circulatory/nervous systems aid in controlling the warming or cooling of their body.
With the harsh winter conditions in the northern states, rattlesnakes need to find an underground refuge for the winter months. Early fall frosts and shortening daylight, encourage snakes to move toward the dens, normally found on hillsides, bluffs, and rocky outcrops with underground openings used as denning sites. Snakes will also den up in holes or burrow systems of prairie dogs or other animals. Any such underground hole, crevice, mammal burrow, or other retreat area must be deep and extend to a depth below the frost line. The dens are normally found on hillsides with a southerly sun exposure allowing for spring and fall basking in the sun. Preferred dens are found on higher elevations above creeks and drainages that may be prone to spring flooding. Snakes cannot dig their own holes, although they can push or root out material with their noses. Vacant holes left behind by other animals are often used as escape cover or denning over the winter months. The first freezing temperatures in the fall months, snakes start their movements toward the den and will congregate near the den until the lower temperatures drive them underground. In the late March or April, triggered by increasing ground temperatures, the snakes will move toward the ground surface or the den opening. With the warming nighttime temperatures and the prolonged period of sunlight, snakes leave the den to find food, mate, and have young during their summer travels. Throughout the summer months, the dens are abandoned and the snakes will travel 2-4 miles from their den. In a Wyoming study, radio transmitters were implanted in various snakes and one female rattlesnake traveled a distance of 8 miles from its den. Snakes return to the same den year after year, provided the den is not disturbed or destroyed. These dens or hibernaculums have been used by many generations of snakes over the years. Some people feel that snakes leave scent trails or pheromes to identify past travels. Other snakes, such as juveniles, may use their sense of smell to follow the odor or pheromes trails of adult snakes, to locate their dens.
All snakes are predators and must locate their prey before they seize it. A snakes vision can detect movement out to about 40 feet, closer objects are seen more sharply. Rattlesnake eyes are lidless, but are protected by a hard transparent covering or scale. The pupil or the black portion of a rattlesnake's eye is elliptical, not round as with the non-venomous snakes such as the racer. The vision of many snakes is better suited for nighttime searching rather than daytime activity. The eyes initiate the visual prey response, then the senses of smell or thermosensitivity come into play.
Rattlesnakes and other snakes lack external ear openings, but snakes are not deaf. Their outer body scales and bones are sensitive to air or ground vibrations. Snakes have two senses of smell: 1) external nostrils, lined with olfactory cells for picking up various odors, but the nose is mainly used for breathing and 2) the forked tongue, is their primary sensory organ for smelling. The tongue is a sensory device for the Jacobson's (vomeronasal) organ. This chemoreceptive organ lies within paired cavities on the roof of the snakes mouth. The snake extends its tongue, to pick up microscopic airborne particles and gases from the air on the tongues surface. The tongue then transfers these order stimuli into the Jacobson's organ and later the brain identifies them as food, enemy, or a mate. The tongue is also used for tracking the snakes prey. The food eaten by a snake depends upon the animal's size and the environment where it lives. Rattlesnakes eat animals such as mice, ground squirrels, and the young of prairie dogs or cottontail rabbits. They also eat other snakes, lizards, birds, and insects. The average snake will consume 2-3 times its own weight in various food items during the spring to fall months when the snake is away from its winter den.
The snake's skeletal system consists of the skull and jaws (including teeth), a backbone, and ribs. The jaws flex (up to 1-1/2 times the jaw width) to allow snakes to swallow larger prey. All snakes have small-recurved teeth in both the upper and lower jaws. These teeth are not used to chew or tear food, but hold the food items and aid in swallowing. A snake swallows its prey in one piece.
Rattlesnakes have a pair of hollow fangs for delivering venom. These long, hooked structures fold against the roof of the mouth when not in use and point forward when the snake strikes its prey. The venom glands are located below and behind each eye, with a venom duct connecting to the front gum line of each fang. The Eastern Diamondback Rattlesnake has fangs up to 1 inch in length. The fangs of adult Prairie Rattlesnake, will be less than 1/2 inch in length. Fangs that are broken during feeding activities or striking, can also be replaced. The fangs are shed from alternate sockets of the paired maxillary bones on the front edge of the upper jaw. The full-sized replacement fang is aligned adjacent to its predecessor, providing 2 fangs on each side for a brief period. Rattlesnakes have a number replacement fangs, in various stages of growth, in the tissue behind the maxillary bones. These fangs and other teeth are replaced on a monthly schedule. Venom produced by the venom gland is an enzyme/protein complex and is one of the most dangerous natural animal poisons. Venom immobilizes and kills the prey, but also starts the digestive process. The quantity, strength, and characteristics of the venom vary from species to species. A larger snake has longer fangs, greater venom capacity, and a larger body to deliver more forceful strikes. The snake controls the amount of venom injected by the contraction of the muscles surrounding the venom glands. The venom of the rattlesnake is mainly a hemotoxin, affecting the blood and lymphatic systems causing pain and rapid swelling in the victim. Venom from such species as cobras and coral snakes is mainly a neurotoxin, which paralyze the nervous system, stopping breathing and heart action. The venom from some rattlesnakes may have both hemotoxin/neurotoxin characteristics.
The "striking distance" of snakes is much shorter than commonly believed. Cornered or threatened snakes may strike in all directions and from almost any position, giving the impression their striking distance is much greater than it actually is. The normal striking distance is 1/2 the snakes body length. The snake strikes rapidly and effectively by drawing its body into an S-shaped coil and striking forward.
All snakes are covered with scales, which are part of a colorless outer skin layer. Under this skin layer, is another layer that contains pigment cells that give a snake its distinctive color pattern. The arrangement of color patterns, type of scales, and scale rows are all used to identify the various species. Rattlesnakes have a keeled scale, that has a ridge on the center of each scale. Other snakes, such as racers and milk snakes have smooth scales - with no ridges. The skin of a snake is dry, not slimy. Molting or skin shedding is repeated periodically throughout a snake's life. 7-10 days prior to shedding, a fluid is formed between the outside layer of skin and the newly formed skin underneath, helping to loosen the skin for shedding. This fluid causes the eyes and base rattle segment to have a blue or cloudy appearance prior to shedding. The snakes vision is impaired during this time and the snake to go into a period if inactivity or hiding. Just prior to shedding, the eyes will clear and the snake will "crawl" out of its old skin, which peels backward over the body from the head to tail. The snakes skin is the most colorful and bright after the shedding. The outer portion of the shed skin, appears clear or translucent. An older snake may shed its skin 1-2 times a year, but a younger yet growing snake, may shed 3-4 times.
Most people believe that you can age a rattlesnake by the number of rattle segments. If the snake has seven rattle segments, it is believed to be seven years old (one rattle/year). This is not true, since a rattle segment is added to the tail area, with each shedding (2-4 times a year). Rattlesnakes are born with a rattle segment called a prebutton, at the tip of their tail. The juvenile rattlesnake normally sheds it skin within the first seven days after its birth. The prebutton is shed with the skin and replaced with a new underlying button. The shedding frequency depends on how much the snake is eating and growing. Skin shedding is required for the snakes growth and to replace worn skin. In the wild, the rattles get cracked and segments are often broken off. The rattle segments interlock together and are made of a keratin substance similar to horns, feathers, or our fingernails. Many older snakes have the button or other segments broken off and may have only 4-5 rattles remaining. Rattle segments that total 10 or more are rare, but some captive rattlesnakes have had 20+ segments. When frightened, the rattlesnakes use the muscles at the base of their rattles to vibrate or shake the rattle segments together, making the rattling sound - no sand, pebbles, etc. are within the rattles to produce this buzzing sound. Rattles of larger rattlesnakes are bigger and have more rattle segments, that can be heard rattling many yards away. Rattlesnakes do not always rattle prior to striking a victim, but only when threatened or endangered. Most rattlesnakes will stand their ground when cornered or provoked.
Most snakes (70 percent) are oviparous and lay an egg (e.g. bullsnake) with a soft leathery shell for the development of the young. Rattlesnakes are ovoviviparous, giving birth to living young (not from eggs); the fertile eggs develop within the female's body. The young develop coiled in a fetal sac - within a thin membranous wrap - in the female's oviduct area. A female rattlesnake will give birth to an average of 8-12 young (up to 24+) in August or September. The baby rattlers are normally 10 inches in length at birth. In the cooler northern climates, a female rattlesnake gives birth to young only every other year, not annually. The female rattlesnakes exhibit very little maternal care or protection for their young. Some mothers stay close to their young for a few days, mainly due to the exhaustion of giving birth. The young are on their own to find food and protective cover. Like other wild animals, many of the young do not survive beyond their first year of life.
The Black-Tailed Rattlesnake (Crotalus m. molossus) is large and bold. The venom of this snake appears to be highly toxic. Considered dangerous to man. Average length 3 feet, maximum length 5 feet.
The Canebrake Rattlesnake (Crotalus h. atricaudatus) is larger than its close relative, the timber rattlesnake, the canebrake is more irritable, ready to defend itself. Average length 3 feet, maximum length 6 feet.
EASTERN DIAMOND BACK RATTLESNAKE
The Eastern Diamondback Rattlesnake (Crotalus adamanteus) is the largest of all venomous snakes in the United States. Sullen disposition, bold and sometimes aggressive. Fangs can measure one inch in large specimens. Venom is toxic. Average length 5 feet, maximum length 7 feet.
The Massasauga Rattlesnake (Sistrurus c. catenatus) is highly toxic to man. There are authenticated fatal bites in man. Often called the Black Snapper or Swamp Rattler. Found in bog areas, swamps and dry fields. Average length 2 feet, maximum length 3-1/2 feet.
The Mojave Rattlesnake (Crotalus s. scutulatus) habits are similar to western diamondback rattler. This species has the most toxic venom of any North American rattlesnake. It is very important to recognize the Mojave rattlesnake's severe respiratory distress. It is often accompanied by its bite. Considered extremely dangerous to man, fatalities are known. Average length 3-1/2 feet, maximum length 4 feet.
The Pacific Rattlesnake (Crotalus v. oreganus) is diurnal in its habits. Bites from this species are common in the Northwestern states. Large enough to cause a fatality. Pacific rattlesnakes can be found from sea level to 11,000 feet. Average length 3-1/2 feet, maximum length 5 feet.
The Pigmy Rattlesnake (Sistrurus m. barbouri), or dusky pygmy, is often called a ground rattlesnake with a tiny rattle that sounds like an insect buzz and can be heard for just a few feet. Venom of the Pigmy rattlesnake is toxic but only a small amount is usually injected into a bite, not considered fatal to a healthy adult. Average length 18 inches, maximum length 2 feet.
The dusky pygmy rattlesnake is the southern counterpart of the "Carolina pygmy" rattler. It ranges from southern South Carolina, westward across southern Alabama and Mississippi, and south throughout the state of Florida. Superficially resembling the Carolina subspecies, it often has a dusted appearance due to the diffuse black mottling in the ground color. Throughout its range, the dusky pygmy rattlesnake inhabits the pine flatwoods, moist prairies and virtually any type of other habitats that offer sufficient cover and are in close proximity to wetlands. Dense populations of this little rattlesnake can be found in many areas of Florida, especially in the moist prairies around the everglades. Dusky pygmy rattlesnakes are one of the species that will readily invade towns and buildings with hurricanes and/or floods, making it an important snake to recognize by first-responders.
As their name suggests, the pygmy rattlesnakes are small rattlesnake species that are light gray to brown to red snakes that display a prominent series of round to ovoid black middorsal blotches flanked by one to two rows of spots on each side of the body. A longitudinally-oriented, rust colored middorsal stripe is often present on the anterior half of the body, but may be lacking in some individuals, or obscured by blending with the ground color in reddish colored individuals.
The Prairie Rattlesnake (Crotalus v. viridus) species has a wide distribution and is common in many areas. The Prairie rattlesnake is responsible for many snake bites. Venom is toxic, fatalities are known. Average length 3 feet, maximum length 5 feet.
Sidewinders (Crotalus cerastes) are a small desert rattlesnake which is a growing concern for snakebites because of residential and recreational areas that are built in the desert. Fatalities are rare from sidewinder rattlesnake bites because of small quantities of venom. Average length 18 inches, maximum length 2-1/2 feet.
The Speckled Rattlesnake (Crotalus m. pyrrhus) is a particularly nervous species. Ready to strike at any intruder. Large enough to deliver a fatal bite. Average length 3-1/2 feet, maximum length 4-1/2 feet.
The Timber Rattlesnake (Crotalus horridus) is sometimes mild tempered and does a good deal of rattling before striking. Commonly found in rocky wooded hills in the northern part of its range. Fatalities are known from the bite of this snake. Average length 3-1/2 feet, maximum length 6 feet.
WESTERN DIAMOND BACK RATTLESNAKE
The Western Diamond Back Rattlesnake (Crotalus atrox) is a large aggressive rattlesnake involved in many snakebites every year in the United States. Having large fangs capable of delivering a large amount of venom in one bite. Average length 4-1/2 feet, maximum length 6-1/2 feet.
The venom of rattlesnakes is designed to kill and begin digestion of their prey. Their strike is extremely fast, measured at 8 feet per second, but they can only crawl about 3 miles per hour - much slower than the normal person walks. To say it is complex is an understatement. It is composed of many proteins, peptides, amino acids, and metals such as zinc, copper, and magnesium. These compounds act in unison to produce three general categories of envenomation results: cytotoxic, hemorrhagic, and neurotoxic effects. Cytotoxins damage endothelial cells and produce marked local swelling and lysis of red blood cells, platelets, and mitochondria. Proteolytic enzymes damage connective tissue, allowing the venom to spread. They also destroy muscle and subcutaneous tissue, producing necrosis. Hemorrhagic compounds induce extravasation of blood and ecchymosis at the bite site. Thrombin-like effects also are produced directly by crotalid venom and result in widespread intravascular coagulation (DIC). Thrombocytopenia also can follow envenomation and can be used as a marker for severity. The more rapid and severe the fall in platelets, the more dangerous the envenomation. Neurotoxicity is produced by blockage of presynaptic nerve transmission. However, the exact composition of the venom, and therefore its effects, vary much more than one might expect with the species, age of snake, diet, season, and even geographic location. The Mojave rattlesnake gives the best example of how much variability can exist.
While somewhat similar in coloring and pattern to a small Western diamondback, the Mojave rattlesnake has the distinction of possessing the most potent neurotoxic venom of all rattlesnakes. It is estimated to be 10 times more potent than any other North American venomous snake on a mg/kg basis. Mojave rattlesnakes actually are divided into type A and type B snakes even though they are the same species. The difference is based on the geographic location: Type A snakes live primarily in southern California, Nevada, Utah, Arizona, Texas, and New Mexico, while type B snakes live only in south-central Arizona. To make matters more complicated, individual snakes with features of both type A and type B snakes also have been found. Type B snakes produce venom that acts similar to other rattlesnakes (hemolytic and proteolytic effects), but type A snakes produce a primarily neurotoxic venom with less effect on local tissues. The neurotoxin in type A snakes is termed Mojave toxin and acts presynaptically to inhibit neuromuscular transmission, causing muscle paralysis. Thus bites by a type A snake will have much fewer local effects and initially may give false reassurance that no venom was injected in the bite. Further, like coral snakes, symptoms of envenomation may be delayed hours after the bite.
CLINICAL EFFECTS OF PIT VIPER VENOM
There are a wide variety of signs and symptoms of pit viper envenomation. The effect in any one case will depend on a number of factors: the species of the snake, its size, health, and age, as well as the location of the bite on the patient and the patient's underlying health. The location of the bite also can give clues as to the cause; most accidental bites occur on the lower extremities while most bites to the upper extremity occur during intentional interaction with the snake. The most common profile in the United States is a young intoxicated male bitten on the hand while trying to interact in some (inappropriate) way with the snake. Bites to the head and neck are less common, but often rapidly will produce severe symptoms. Bites that inadvertently inject venom directly into a vein or artery may produce systemic symptoms in only a few minutes; these patients may not survive long enough to reach the emergency room.
Overall, most pit viper bites produce symptoms in 30-60 minutes. Only a brief overview of symptoms is presented, and readers interested in detailed descriptions are referred to detailed text. Initial findings include burning pain and swelling at the bite site, but in the case of a Mojave rattlesnake bite type A, snakebites may produce little or no pain. For all rattlesnakes, ecchymosis and bullae may take several hours to develop. Beware that in some cases, the edema itself may not appear for several hours and that seemingly mild envenomations suddenly may take a turn for the worse. Mild systemic effects include nausea, vomiting, paresthesias (tingling of the mouth, scalp, or feet), fasciculations, and weakness. Bites from larger species may produce a rubbery, minty, or metallic taste. More severe systemic effects include altered mental status, tachycardia, tachypnea and respiratory distress, and hypotension. Laboratory abnormalities include coagulopathy (prolonged prothrombin time [PT] or partial thromboplastin time [PTT] and decreased platelets), elevated white blood cell (WBC), creatinine kinase (CK) levels, and transaminases. The patient who has underlying medical problems also may experience complications of these conditions, i.e., acute myocardial infarction (MI), acute renal failure, asthma attacks, etc. Symptoms are used to grade the level of envenomation, which is key for defining treatment.
COTTONMOUTH (WATER MOCCASIN)
Cottonmouth (Water Moccasin) (Agkistrodon piscivorus). The cottonmouth or water moccasin is named for its habit of coiling up and exposing the white interior of its mouth when threatened. They are found in the southeastern United States as far west as Texas and as far north as southern Missouri. They are darkly colored (brown or olive) with a yellowish belly as adults. Hatchlings can be much brighter with bands of alternating color looking similar to their cousin the copperhead, but are still darker than copperheads. Like young copperheads, they also have a bright yellow or lime-green tip of the tail used to lure prey. Adults are typically around 3 feet, but have been recorded at 6 feet. They have a heavy body like larger rattlesnakes, and have a reputation for being aggressive. This means they tend to stand their ground when approached. They often are found in or around water. The AAPCC report shows 173 cottonmouth bites treated in 2002 - much fewer than both copperheads or rattlesnakes. Venom is similar to rattlesnake venom, but less toxic, and no deaths from cottonmouths have been documented since the first AAPCC report in 1983. Symptoms and treatment of envenomation are the same as for the copperhead.
When one thinks about snakes indigenous to the hurricane prone areas in the eastern United States, the cottonmouth or water moccasin is probably the first species to come to mind. The cottonmouth is a large dark heavy-bodied snake that ranges throughout a large portion the southeastern United States. Cottonmouths are the largest snakes in the New World Agkistrodon species complex and are the only members of the group that are semiaquatic. Three distinct subspecies are currently recognized; the "eastern", "Florida", and "western" cottonmouths. The Florida cottonmouth ranges from the southeastern extreme of South Carolina through coastal and southern Georgia, south throughout the state of Florida and west along the Gulf Coast to the eastern face of Mobile Bay in Alabama.
As the southernmost subspecies of cottonmouths, A. piscivorus conanti ranges from the southeastern extreme of South Carolina through coastal and southern Georgia, south throughout the state of Florida and west along the Gulf Coast to the eastern face of Mobile Bay in Alabama. It is the largest member of the A. piscivorus complex. Its head is conspicuously marked with distinctive vertical stripes on the rostrum and mental regions creating a "handle bar mustache-like" marking on the rostrum when viewed from the front, an effect that is nicely visible in the specimen pictured here. The head also bears a prominent pair of bilateral dark cheek stripes that are markedly bordered by light areas above and below; a pattern that can be so striking, untrained people accustomed to seeing the less colorful "western" species, sometimes have trouble identifying the Florida subspecies as a cottonmouth.
Copperhead (Agkistrodon contortri). Copperhead snakes are a close relative of the cottonmouth, and both are considered moccasin-type animals. They are found in the southeastern United States and range as far west as Texas and as far north as New York. They are named for the copper colored bands that alternate with darker brown bands along the length of the body. As hatchlings, they also have a bright yellow tip to the tail, which they use as a lure to bring prey (lizards) into striking range. They are not as big as full-grown rattlesnakes (at fewer than 3 feet as adults) and tend not to be as heavy as cottonmouths. The AAPCC 2002 report shows 889 patients were treated for copperhead bites, compared to 1150 for rattlesnake bites and 173 for cottonmouth bites. While venom is similar to other pit vipers, copperhead bites tend to be less potent, and no deaths have ever been reported to the AAPCC.
Symptoms of envenomation include pain and swelling at the site, which can progress rapidly. Cytotoxins in the venom produce ecchymosis (the passage of blood from ruptured blood vessels into subcutaneous tissue, marked by a purple discoloration of the skin) and hemorrhagic bullae (blister) similar to rattlesnakes. Systemic signs of tachycardia and hypotension can occur. Laboratory studies are the same as for rattlesnake envenomation. (See section on Grading of Pit Viper Envenomation.) One study of cottonmouth and copperhead bites demonstrated the lack of systemic toxicity in most bites. A series of 55 patients envenomated by these snakes found that 95 percent of bite victims had local swelling and pain, but only 14 percent had any systemic symptoms (nausea, vomiting, or tachycardia). Further, none of the 55 had any laboratory abnormalities, and none developed any significant tissue damage or loss of function. Although symptoms are generally less severe than with rattlesnake bites and most bites do not meet criteria for antivenom use, young or elderly patients may have more severe symptoms.
GRADING SCALE FOR SEVERITY OF SNAKE BITES
Degree of Envenomation Presentation Treatment 0. None Punctures or abrasions; some pain or tenderness at the bite. Local wound care, no antivenin. I. Mild Pain, tenderness, edema at the bite; perioral paresthesias may be present. If antivenin is necessary, administer about five vials.* II. Moderate Pain, tenderness, erythema, edema beyond the area adjacent to the bite; often, systemic manifestations and mild coagulopathy. Administration of five to 15 vials of antivenin may be necessary. III. Severe Intense pain and swelling of entire extremity, often with severe systemic signs and symptoms; coagulopathy. Administer at least 15 to 20 vials of antivenin. IV. Life-Threatening Marked abnormal signs and symptoms; severe coagulopathy. Administer at least 25 vials of antivenin. * Because of their less potent venom, Grade-I copperhead bites are usually not treated with antivenin.
GRADING THE SEVERITY OF THE BITE
A popular scale for grading the severity of pit viper bites and estimating the antivenin dose is presented in above. It is important to remember that a patient must have serial evaluations, because an envenomation that appears to be mild on presentation can soon exhibit the hallmarks of a severe envenomation. Doses of antivenin must not be reduced for children or small persons, since the amount of venom that needs to be neutralized is the same.
GRADING OF PIT VIPER ENVENOMATION
As pit vipers account for 98 percent of all bites treated in the United States, an envenomation grading system has been developed for use with North American pit viper bites. It is important to remember not to use this grading system for bites from any other venomous snakes, especially coral snakes, as it likely will lead to inappropriate treatment. Also, type A Mojave rattlesnakes have a significant neurotoxic component to their venom, and this grading system may not apply well in their case either. The grading system is designed to assist with decisions on antivenom use and gives a rough idea of how much antivenom may be required.
In general, there are four grades of bite symptoms from no symptoms (dry bite), to mild, moderate, and severe symptoms.
Dry bites are described in a previous section. Mild envenomations have only local pain and swelling with no systemic or laboratory abnormalities. Moderate envenomations have progressive swelling at the site, mild laboratory changes, and non-life-threatening systemic symptoms. It is good practice to begin marking any swelling around the bite site with a marker to keep track of progression. Times also can be written to provide other physicians with objective measures of the swelling. Severe envenomations have rapid local swelling, dramatic laboratory changes, and dangerous systemic symptoms. Each patient with an envenomation is different, and it is critical to remember when using this system that the grading ultimately is determined by the most severe sign, symptom, or laboratory finding in each category. In other words, if one patient only has mild local swelling and normal laboratory test results, but has hypotension (systolic BP less than 80 mm Hg), then the patient is classed as a severe envenomation. Also be aware that not all severe envenomations may appear so in the first 1-3 hours. Patients with only mild symptoms initially need close monitoring so that if rapid progression occurs, they will be treated as quickly as possible.
One often sees significant swelling of a limb after envenomation that can mimic compartment syndrome, but compartment syndrome after snakebite actually is not a common occurrence. One must be vigilant, though, as typical signs of compartment syndrome (i.e., pain, paresthesias, pallor, cool skin) also may be present to some degree as a result of the action of the venom. Compartment pressures should be measured to ensure that the diagnosis of compartment syndrome is neither overlooked nor over-diagnosed. Increased compartment pressures (30-40 mm Hg) can be treated with additional antivenom dosing, elevation of the limb, and 1-2 g/kg of mannitol (if the patient is hemodynamically stable). If pressures are not reduced below 30 mm Hg by these maneuvers, the patient should be referred for further evaluation by an orthopedist or general surgeon.
Laboratory tests are ordered to evaluate the severity of envenomation in most cases. The exception is for coral snake bites, where laboratory abnormalities are not a feature of envenomation. A typical panel for pit viper envenomation would include: complete blood count (CBC), PT, PTT, fibrinogen and fibrin degradation products (PDP), d-dimer, electrolytes, blood urea nitrogen (BUN), creatinine, CK, urinalysis (UA) for myogloinuria, with an electrocardiogram (ECG) and ABG only in more severe cases. Chest X-rays may be obtained in patients with respiratory symptoms, and plain films of the bite may be useful to rule out retained fangs.
There are currently three types of antivenom available for use with envenomation by North American snakes: coral snake antivenom (see next section), and two types of pit viper antivenom. The older type of antivenom is a polyvalent antivenom (Antivenin Crotalide Polyvalent) manufactured by Wyeth. Rumors exist that the manufacturer recently has stopped production of this antivenom, but this is not the case. Emergency supplies are maintained by the manufacturer, but may take 24 hours for delivery. The newer type of antivenom is CroFab (Crotalidae Polyvalent Immune Fab Ovine). Any patient to whom antivenom is given should be referred for admission, usually to an intensive care unit (ICU) setting. A final common point for both types of antivenom: The dosing is the same for pediatric and adult patients. The amount of antivenom required is a function of the dose of venom received, not a function of the patient's size.
Polyvalent Antivenom: The polyvalent antivenom is made using the same method since production began in 1954. Venom from four species (Eastern and Western diamondbacks, South American rattlesnake, and the fer-de-lance) is injected into horses, and antibodies are purified to make the antivenom. Both the South American rattlesnake and the fer-de-lance are not native U.S. snakes, but do account for numerous snakebites in South America. Even so, through cross-reactivity the polyvalent antivenom is effective against all envenomations from any viper native to North, Central, or South America. (However, it is important to note that the polyvalent antivenom does not provide as effective coverage for type A Mojave rattlesnake envenomations as does CroFab.) Due to imperfections in the purification process, only 15-25 percent of the resulting antivenom contained IgG. Other proteins contained in the polyvalent antivenom are responsible for most of the anaphlyactoid and serum sickness reactions.
The manufacturer recommends skin testing for individuals in whom antivenom is to be used, but this is not always endorsed by practitioners. Advocates suggest that skin testing will help identify patients who have an obviously severe hypersensitivity so that caregivers can be ready to treat allergic reactions. Opponents of skin testing point out that skin testing is an inaccurate way to predict possible allergic reactions, and antivenom will be given anyway for serious envenomations. Up to 28 percent of patients will have a negative skin test and still have an acute allergic reaction, and up to 30 percent who have a positive skin test will not have an allergic reaction. The bottom line is as follows. Do not perform skin testing unless antivenom is to be given; do not use for dry bites, as the patient possibly will be sensitized unnecessarily. Also, do not waste time with skin testing in cases of severe envenomations. Be prepared to manage anaphylaxis in any patient when antivenom is given regardless of skin test results. If time permits, pre-treat the patient with at least 1 liter crystalloid, H1 (diphenhydramine 25-50 mg IVP) and H2 (ranitidine 50 mg IVP) blockers before antivenom is given.
The initial dose of polyvalent antivenom is 10 vials, but some species (Eastern diamondback) usually are given higher doses (10-20 vials). Hemodynamically unstable patients should be started with 20 vials. Be aware that one must reconstitute the antivenom and that bottles must be handled gently to avoid denaturing the IgG. Do not shake vials to dissolve the antivenom, only swirl the solution. It will take 20-30 minutes to reconstitute each vial, so be sure to reconstitute all the vials simultaneously. Add the vials to 250 or 500 mL of 5 percent dextrose in water or normal saline. Pediatric patients should have their antivenom reconstituted in 20-40 mL/kg of normal saline (up to 1 liter). Start the infusion slowly for the first 10 minutes and if no complications develop, finish the infusion in 1 hour. Patients who have had a positive skin test reaction (wheal at injection site) should have initial doses given even more slowly, and the initial dose should be completed in 2 hours instead of 1 hour. Treat anaphylaxis or systemic reactions by stopping the infusion and treating with epinephrine and additional diphenhydramine, steroids, and ranitidine. If systemic envenomation symptoms are life-threatening, the antivenom should be restarted by further dilution and slowing the infusion. It can be a difficult decision to proceed with antivenom treatment in patients who also have manifested signs of significant allergic reaction, and these cases must be decided on an individual basis. Strongly consider prophylactic intubation in patients when significant allergic reactions develop. If symptoms continue to progress despite antivenom treatment, the initial dose can be repeated in about 1-2 hours. This process continues until the envenomation symptoms stabilize.
CroFab: CroFab was approved by the FDA in October 2000 and is produced from sheep exposed to the venom of four different North American snakes: the Eastern and Western diamondback, the cottonmouth, and type A Mojave rattlesnakes. Four different groups of sheep are given one type of venom each, and IgG is collected and pooled from each. The IgG is further modified into Fc and Fab fragments. The Fab fragments are isolated using affinity chromatography against the venom for which they were developed. These Fab fragments are a purer version of the polyvalent antivenom and are less immunogenic. Also being a smaller molecule, the Fab fragments better penetrate tissues and are cleared more easily by the kidneys. Animal studies find that CroFab is 3-10 times more potent than the polyvalent antivenom. Although the manufacturer suggests use for mild and moderate envenomations, it also is used clinically for severe envenomations with no reported problems. There is a hotline to call for any questions on CroFab use: 87-SERPDRUG or 877-377-3784.
Dosing for CroFab is significantly different than for polyvalent antivenom. Skin testing is not recommended for CroFab, and prophylaxis for allergic reactions is not standard either. The initial starting dose is only 4-6 vials diluted in 250 mL of normal saline. Reconstituting CroFab still takes between 20 and 30 minutes, and the vial should never be shaken as activity of the antivenom will be lost in the process. As with the polyvalent antivenom, start the initial infusion slowly for the first 10 minutes and then give the remainder in 1 hour if no allergic symptoms appear. The patient is observed for another hour, and if symptoms progress an additional 4-6 vials are given every 2 hours until stabilization occurs. Reports show that most patients are stabilized with 8-12 vials. The package insert and some clinicians recommend that after stabilization of symptoms, 2 vials should be given every 6 hours for a total of 3 additional doses to prevent re-occurrence of symptoms. The efficacy of these extra doses still is debated and is not advised by some toxicologists. CroFab has been used in pediatric cases with success similar to adult cases. Be aware the coagulopathies, secondary to thrombocytopenia, have been reported to reoccur up to 2-3 weeks after CroFab treatment, and some authors recommend bringing the patient back for recheck during that time. The mechanism of this thrombocytopenia (thrombocytopenia is an abnormal drop in the number of blood cells involved in forming blood clots. These cells are called platelets) is unclear.
Lastly, although polyvalent antivenom was only produced from two North American rattlesnakes (and two Central or South American species), it was found to be active against all venomous vipers in North, Central, and South America. Apparently, CroFab may have similar cross-reactivity. Initial studies of CroFab use for copperhead and Southern Pacific rattlesnakes show CroFab also is effective for envenomations by these snakes.
Coral snakes (Micrurus) are a member of the Elapidae family and are related to cobras, kraits, and mambas. Coral snakes are notable exceptions to pit vipers in many ways. They are brightly colored, small, nocturnal snakes with neurotoxic venom that is more like cobra venom than pit viper venom. They also have no heat-sensing pits. Only three species of coral snake are found in the United States. The Eastern coral snake (Micrurus fulvius fulvius) is native to North Carolina, South Carolina, Florida, Louisiana, Mississippi, Georgia, and Texas. The Texas coral snake (Micrurus fulvius tenere) is native to Texas, Arkansas, and Louisiana. The Western or Sonoran (Micruroides euryxanthus) coral snake is native only to Arizona and New Mexico. It is important to note that only bites of the Eastern or Texas coral snakes are considered dangerous and are treated with antivenom. Bites of the Western or Sonoran coral snake are considered mild, and no fatalities have been documented.
All coral snakes are small and thin, only 2 feet long when adults, and resemble harmless king snakes in appearance. Color bands alternate in a red, yellow, black, yellow, red repeating pattern, completely encircling the body, and the snout is always black. Several mimic milk snakes and king snakes (scarlet king snake, Mexican milk snake), and an easy phrase to tell them apart is, "Red touch yellow, kill a fellow; red touch black, venom lack." Native U.S. mimic snakes also always have red snouts, whereas true coral snakes have black snouts. Notable exceptions are the Mexican coral snake, which lacks much yellow coloring and whose red bands lie next to black ones, and the Mexican milk snake (non-venomous), which has a black nose.
Comparing the venomous coral snake to similar non-venomous species Remember the rhyme:
Red on black - venom lack (or friend of Jack)
Red on yellow - kill a fellow
It is just a rhyme, however it is an accurate way to quickly tell a venomous coral snake from a harmless, non-venomous member of a similar species. Another way to tell is that the color rings on the coral snake go all the way around the snake, the underside looks like the top. This is not seen in similar species, their rings are only on top. Do not attempt to determine species using this method since it means you are too close!
Texas coral snakes are extremely shy and non-aggressive. Although their mouths are smaller than most venomous snakes, they can still inflict a serious bite if handled. Coral snakes eat mostly other snakes and small reptiles and are members of the same family of snakes as the cobras of India. Fangs are small (1-3 mm) and fixed in position, unlike large retractable pit viper fangs. They may be difficult to see, even in dead specimens. Unlike other snakes, the coral snake usually must hold on and chew for effective envenomation to occur. One study found that 85 percent of victims of a coral snake bite reported that the snake hung on and actually had to be actively removed. Even so, bite wounds are very small and may be overlooked in the emergency department. When bites do occur, they tend to be in warmer months (April-October) and occur after dark. Coral snake bites are rare, accounting for fewer than 1 percent of all venomous snakebites in the United States. The 2002 AAPCC data list 88 coral snake bites that year. The relatively low number of bites is due in part to their nocturnal, burrowing lifestyle, and the fact that they are small, shy by nature, and rarely encountered by people. This is fortunate, as the neurotoxic venom they inject often produces very few local symptoms. However the Eastern coral snake venom is very potent and it is estimated from mouse studies that an average adult Eastern coral snake carries enough venom to kill 4-5 adults. Of all the native venomous snakes, only the Mojave rattlesnake produces more potent venom. The Texas coral snake's venom is similar to the Eastern coral snake, but is considered less potent. While venom from the Sonoran coral snake also is similar, it only seems to produce very mild if any CNS effects. Thus Sonoran coral snake bites are considered less dangerous. As discussed below, the Eastern and Texas coral snakes are the only native snakes whose antivenom is given for true bites regardless of patient signs and symptoms. Symptoms are well documented to be delayed for 12 hours, and then rapidly to progress. Even worse, when symptoms develop they often are resistant to antivenom treatment.
Do not confuse the envenomation grading scale developed for evaluation of pit viper bites for evaluation of a coral snake bite; it is not applicable, and likely will result in inappropriate treatment. In nearly half of true envenomations, there is no redness or edema at the bite site because coral snake venom contains very few cytotoxins. Bullae are seen in only 5 percent of cases. Ptosis or nausea/vomiting often are the earliest signs of envenomation. Signs of coral snake envenomation also include sweating, headache, or abdominal pain. Parathesias or altered mental status can develop (decreased sensorium or euphoria followed by focal neurologic deficits). Cranial nerve dysfunction (i.e., ptosis, dysphonia, dysphagia) or peripheral motor nerve deficits often are seen. Proximal muscle paralysis can occur with subsequent respiratory failure, aspiration, and death. Respiratory failure ultimately is the most common cause of death, but no deaths have been reported after introduction of coral snake antivenom. Further, supportive treatment alone can be effective as most deaths are due to failure to initiate ventilatory support early on when symptoms develop. While paralysis may last only 3-5 days, complete neurologic recovery from effects of the venom may take weeks. In contrast to pit viper venom, coral snake venom contains few if any hemotoxins, and coagulopathies are not seen in coral snake envenomation. Thus, the only useful laboratory test to obtain when treating a patient bitten by a coral snake would be an arterial blood gas (ABG) to assess respiratory status.
TREATMENT OF CORAL SNAKEBITES
Treatment of coral snake bites is very different than for any other native venomous snakebite. Since coral snake venom is neurotoxic, very few if any local symptoms may be present. Again, the grading scale in is not to be used for coral snakebite evaluation. Resist the temptation to underestimate the potential risk to these patients.
There is no CroFab-type antivenom for coral snakes, only the older type polyvalent antivenom made from horse serum is available. Thus, treatment should be similar to polyvalent-type antivenom used for pit viper bites. Though recommended by the manufacturer, skin testing is not indicated as it is an inaccurate way to predict possible allergic reactions, and antivenom will be given for any envenomations.
Antivenom treatment is to begin immediately for any confirmed Eastern or Texas coral snakebite. Again, antivenom treatment is not anticipated for the Sonoran or Arizona coral snake. Further, antivenom manufactured by Wyeth-Ayerst (Antivenin Micrurus fulvius) is made using only Eastern coral snake venom and has no proven benefit against Sonoran coral snake venom. Future production of coral snake antivenom by the manufacturer is in question, but as of early 2005 emergency supplies are still available. As previously mentioned, once the neurologic complications of coral snake envenomation appear they may not respond to antivenom treatment. Patients with respiratory distress should be treated aggressively and intubated early in the course of treatment.
If a patient has been bitten by an Eastern coral snake, or snakebite is strongly suspected, 4-6 vials of coral snake antivenom (Antivenin Micrurus fulvius) should be given immediately, and the patient should be admitted for observation. If any symptoms develop while in observation, an additional 10 vials may be required, and the patient should be monitored in an ICU setting for possible respiratory failure. Patients must be examined closely for any neurologic deficits; ptosis or other cranial nerve abnormalities may be subtle.
Pre-treat the patient with at least 1 liter crystalloid, H1 (diphenhydramine 25-50 mg IVP) and H2 (ranitidine 50 mg IVPB) blockers. Start with 4-6 vials diluted in 500-1000 mL (20 mL/kg for pediatric patients). Infuse the antivenom slowly at first, and the health care provider should remain at bedside for at least 15 minutes to watch closely for signs of allergic reaction. If no reactions occur, infuse the entire dose in 2 hours. If symptoms continue, an additional 3-5 vials are given. Most envenomations do not require more than 10 vials.
Epinephrine, steroids, and additional antihistamines should be given for any signs of allergic reaction, and antivenom infusion halted. After the reaction is treated, one must decide whether to continue the infusion or treat the envenomation with supportive care only. Keep in mind that respiratory paralysis after coral snakebite has been known to take anywhere from days to weeks of mechanical ventilation. Again, all patients treated for coral snakebites should be admitted to an ICU setting, even in the case of a dry bite. As mentioned previously, symptom onset can be delayed 12 hours and may begin with respiratory distress. Unfortunately, the manufacturer may discontinue antivenom production in the near future, and health care providers will be left only with supportive care until another company produces antivenom.
EXOTIC (NON-NATIVE) VENOMOUS SNAKES
Herpetology as a hobby has grown significantly in the past two decades. Most large U.S. cities now have reptile shows where virtually any adult can purchase a wide variety of non-native (exotic) snakes and other reptiles. As a result, the number of patients seen for bites from exotic snakes in emergency departments across the country has grown. Data show that before 1960, only 4 percent of bites were from non-native species. By 1972, 15 percent of 410 patients hospitalized for snakebites were bitten by non-native species. In 1984 it was estimated that 30 patients were treated in the United States for bites from exotic snakes, but data from the 2002 AAPCC Toxic Exposure Surveillance System found 125 such cases.
Another way to think of this issue is to consider the number of snakebites treated from captive animals, since non-native species are held in captivity. One author reviewed consultations for non-native venomous snakebites from 1977 to 1995 and found that these species were responsible for 33 percent of the consultations. Further, fully 48 percent of all bites (native and non-native) were from captive species. The current edition of Auerbach's Wilderness Medicine put this issue in perspective by stating that an emergency department health care provider in an urban hospital in the eastern or midwestern United States is almost as likely to be confronted with a bite of an exotic venomous snake as with that of a species native to North America.
The most popular venomous non-native snakes sold in the United States are cobras and vipers (puff adder, gaboon viper, and rhinoceros viper) from Africa and Asia. There are some data to show that cobra bites are very common among non-native bites, with cobras causing 40 percent of non-native snakebites in one series. Interestingly, native U.S. venomous snakes are very popular in Europe, with one report on snakebites in France showing that Crotalids (U.S. rattlesnakes, copperheads, and cottonmouths) were responsible for a large number of non-native snakebites treated there.
CONFRONTATION WITH A NON-NATIVE SNAKE BITE
The key is identification of the species, as treatment is based strictly on the snake involved. This is very important; antivenom for exotic snakes is species- and even region-specific. In other words, antivenom for a Pakistani cobra is unlikely to be effective if used for a Chinese cobra bite. The best approach is to ask the patient what type of snake caused the bite. In most cases, the patient can provide reliable information on the species of snake he or she owns. In short, if the patient says he or she was bitten by an Indian spectacled cobra or West African gaboon viper, the treating health care provider should believe him or her.
Treatment of victims of exotic venomous snakebite will depend entirely on the species of snake involved. This section will present a brief overview of symptoms and treatment of the snakes most likely to be encountered. Remember, one must identify the snake to determine what effects are likely, if antivenom for this species exists, and where it may be obtained. The local zoo often is a good resource for identification of the species and for exotic snake antivenom as any good herpetologist will keep his or her own supply of appropriate antivenom when keeping exotic venomous snakes. One also can call the national poison control center number to speak with a toxicologist (800-222-1222) that automatically connects to the nearest poison control center. The Arizona Poison and Drug Information Center (520-626-6016) also is a good back-up resource for venomous snakebite treatment and maintains a database on antivenom stocks in the United States. There is an antivenom index maintained by the American Zoo and Aquarium Association (www.aza.org) that contains valuable data as well. It includes a list of medically important venomous snakes, recommendations for which antivenom to use in treatment, where these antivenoms can be found in the United States, and a list of antivenom manufacturers around the world. This index must be purchased in advance or one must be a member to log into the index online.
Cobras are probably the most likely exotic snake to bite and cause a patient to present for treatment in the United States. As mentioned previously, one series found that cobras were responsible for 40 percent of non-native snakebites treated in the United States. They are very popular in the pet trade, and to many herpetologists they represent the quintessential venomous snake. Like the coral snake, they belong to the Elapidae family. Snakes in this family are found around the world including the Indian Ocean and the Pacific. Most venomous snakes in Australia are Elapids and in some tropical areas particularly in the rural tropics, deaths caused by Elapids is a significant medical problem.
The cobra neck can be flattened to form the infamous hood that is universally recognized. The king cobra is the largest of all venomous snakes, reaching up to 5 meters (18 feet) in length. Their preferred preys are rodents and birds. They do, however, also eat other snakes and some particular species as for instance the King Cobra, is said to have a preference for snakes. They kill their prey by injecting their neurotoxic poison into the prey through their fangs. The neurotoxin of cobra snakes has the ability of destroying the communication across the connection constituting the contact points between nerve cells. When this communication is destroyed, the victim's muscles cannot be used in any kind of defense.
Cobra venom is among the most potent of all the world's venomous snakes, and a single bite from an adult king cobra is estimated to deliver enough venom to kill a full-grown elephant or 20 people. Not all cobra bites are venomous. Some bites are so called "dry bites" which may cause serious infections due to bacteria from the cobra's mouth. It is estimated that approximately 75 percent of people receiving a bite from a cobra snake will eventually die from the medical complications arising from the bite. A venomous bite (not dry) from a cobra snake will in the most severe cases cause death within 10 minutes. Since its neurotoxic venom acts by inhibiting the transfer of transmitter substances across the synaptic cleft, mechanical ventilation of a victim may be a way of increasing the victims chance of survival. If antivenin is applied prompt its of uttermost importance, that the species that caused the bite is identified, since correct management of the patient is dependent on the prompt administration of the correct antivenin.
There are a variety of cobra species found in Asia, Africa, and Indonesia. This is an important fact because the venom of each species will vary enough that antivenom produced from one species may not be effective for another. In other words, Indian cobra antivenom may not treat a bite from a Chinese cobra or a Pakistani cobra. Further, some cobra venom is neurotoxic (king cobra) while that of other species (spitting cobras) is more locally damaging like that of a rattlesnake. Patients injected with neurotoxic venom present like those with a coral snakebite; few local symptoms but progressive neurologic dysfunction can develop. Spitting cobras also spray venom with unerring accuracy at the eyes, and although it will not be absorbed systemically, the venom will cause corneal ulcers and blindness if not washed away quickly. Cobra venom also contains a cardiotoxin that binds to heart cells and permanently depolarizes their membranes. Baseline laboratory studies similar to those ordered for native pit viper envenomations (CBC, renal function tests, PT/PTT) should be ordered. As with coral snakebites, the pit viper envenomation grading scale is not to be used. Any patient with a bite from a cobra should be treated as if a serious envenomation has occurred. Be prepared to provide ventilatory support and attempt to locate antivenom as previously described.
Mambas (green or black), kraits, sea snakes, and Australian snakes such as the taipan and tiger snake all produce neurotoxic venom and should be treated in a similar fashion to cobra bites. Again, remember that each of these snakes has its own antivenom and antivenom from one species will not treat envenomation of another species.
Vipers commonly seen in the pet trade include the Russell's viper (Asia), gaboon viper (Africa), puff adder (Africa), eyelash vipers (Mexico, Central America), and Wagler's viper (Asia). These vipers produce envenomation symptoms similar to North American pit vipers. Patients experience hemorrhage and local necrosis, and significant local pain and swelling. More severe cases will have systemic signs of hypotension, pulmonary edema, and renal failure. Antivenom is available for many of these vipers, but again geographical differences are important. An extreme example is Russell's viper where antivenom is effective against Russell's viper from one area but not those from a different geographic region.
Finally, one may be presented with a choice between using a polyvalent antivenom made from venom from several snakes in a region, and using a monovalent antivenom made from only one snake species. The monovalent antivenom always should be used if the snake has been positively identified. Monovalent antivenoms are more effective in clinical use than polyvalent antivenoms as they provide more specific treatment. If in doubt on the identification of the snake, use the polyvalent type of antivenom. Using monovalent antivenom for the wrong species will result in no protection for the patient, but all of the risks from allergic reaction.
There are only two venomous lizards that exist, and only the Gila Monster is native to the southwestern United States. The Mexican beaded lizard is, as the name suggests, found in Mexico. Both are similar in appearance: stocky, with large heads and strong jaws. Venom is similar to that of rattlesnakes, but is not delivered by hypodermic-like teeth. Most bites occur from captive animals rather than attacks in the wild.
Gila Monsters (Heloderma suspectum) tend to bite and hold on if provoked. The shy and reclusive Gila Monster strikes back with a tenacious venomous bite, chewing to force venom into the wound by capillary action along grooves in the teeth. The lizard's venom flows from glands in its lower jaws, along groves in its teeth, and into the bite wound. Most of its prey, such as rabbits and rodents, are quickly killed by its powerful jaws. Envenomation is not extremely effective and only occurs in up to 70 percent of bites.
MEXICAN BEADED LIZARD
Mexican Beaded Lizard (Heloderma horridum) is a less colorful lizard than its cousin, the gila monster. The Mexican Beaded Lizard is a large, venomous lizard that originates in Mexico and Guatamala. It has black or pale yellow bands or is entirely black. Their name, beaded lizard, comes from several tiny beads on their skin called ostioderms. Very strong legs let this lizard crawl over rocks and dig burrows. It is short-tempered. It will turn and open its mouth in a threatening manner when molested. Its venom is hemotoxic and potentially dangerous to people. It is found in arid or desert areas, often in rocky hillsides, coming out during evening and early morning hours. The average length of the Mexican Beaded Lizard is between 30-36 inches in length and about 3.5 to 6 pounds in weight. It is commonly found in Mexico through Central America.
Treatment first consists of removing the animal from the patient, which may not be an easy task. Options include running hot water over the lizard or gently prying the jaws apart with a metal or wooden object. Care must be taken so that the person removing the animal does not also become a bite victim. If envenomated, burning pain and local swelling likely will be present. Systemic reactions with hypotension and tachycardia sometimes also are seen. Electrolytes, renal function, CBC, and coagulation studies should be ordered as in some cases coagulopathies have been reported. Anyone with systemic signs of envenomation should be admitted for further observation/treatment. Patients with apparent dry bites (no envenomation) should be observed for 6 hours and may be discharged if no symptoms develop. Bite wounds should be X-rayed as teeth are relatively large and often are found in the wounds. Prophylactic antibiotics are not indicated, but wound rechecks at 24-48 hours should be performed.
WAYS TO AVOID SNAKE BITES
Learn how to identify the venomous snakes found in the area. Learn key differences between non-poisonous and poisonous snakes. To identify a snake, look at the snakes tail and see if the tail is pointed or if the end portion has a rattle segment(s). Some rattlesnakes may have only a stub of the tail. These snakes may have lost the last portion of their tail into the skin section including the rattles. The tail may have been cut off by some farm machinery or bit off by another animal. Rattlesnakes do not regenerate their tails like lizards, but will have only a blunt stub of a tail with no rattles. Other venomous snakes such as copperheads, cottonmouths, and coral snakes have pointed tails. These snakes are found across the southern U.S.
Leave snakes alone. Do not disturb them, attempt to handle them, or kill them. Many people (about 1/3 of snakebite cases) are bitten because they try to kill a snake or get a closer look at it. If you come across a snake, maintain a safe distance. Any sudden movements may scare the snake and it may strike.
Stay out of tall grass, especially with heavy underbrush, unless you wear thick leather boots, and remain on hiking paths as much as possible and watch where you step. Snake bites, such as those inflicted when snakes are accidentally stepped on are nearly impossible to prevent. Do not jump or step over logs, rocks, or plant material. Walk around these obstacles. Look closely at the ground before crossing over or under fences.
Wear suitable clothing and footwear when outdoors. High-top leather boots provide adequate protection for the feet and ankles. Low cut shoes or sandals should not be worn in rattlesnake country, especially at night. Rattlesnake fangs can penetrate through clothing, Wearing loose-fitting long pants is better than close binding styles when walking outdoors at night in areas possibly inhabited by venomous snakes. Snakes tend to be active at night and in warm weather.
Keep hands and feet out of areas you cannot see. Be careful where you put your hands or feet and where you sit. Most snakes are inactive animals that depend upon concealment for protection. A rattlesnake in its natural habitat is almost impossible to see, when motionless and silent. Do not depend on a rattlesnake to rattle before it strikes. Most rattlesnakes will not rattle unless they are frightened or endangered. If you are camping, check your sleeping bag before getting into it. In the morning, check your boots, clothing, and bags before sticking your feet and your hands into them. Snakes are attracted to the warmth and dark places to curl up and sleep.
Look before you reach under rocks or a log and be careful in the outdoors when turning over logs, rocks, or other large objects. Do not pick up rocks or firewood. Be cautious and alert when climbing rocks. A snake may be laying underneath resting or looking for food. When hiking
If you encounter a snake when hiking or picnicking, just walk around the snake, giving it a little berth - six feet is plenty. Stay at least a body length away from the snake. Snakes can only strike within 1/2 to 2/3 the length of their body, but it could be further if they are facing downhill. so a 3-foot snake could reach up to 2 feet away. Snakes normally are not aggressive, but be prepared to retreat if a snake comes toward you. It may only be seeking escape cover.
Under no circumstances should rattlesnakes be considered as pets. Even with professional snake handlers suffer bites. Any snakebite can be a serious situation and a medical nightmare! Extreme care should be used when confronting any snake. Capturing a live venomous snake should only be done by an experienced person using a snake tongs or a similar holding device. Commercially made snake tongs are in lengths of 26-50 inches and can be purchased from www.rattlesnakecatcher.com.
BENEFICIAL ASPECTS OF SNAKES
Before deciding to kill a snake in your yard or garden, consider the many benefits of snakes.
Snakes are one of nature's most efficient mousetraps, killing and eating a variety of rodent pests. Although snakes will not eliminate pests, they do help keep their numbers in check. Some harmless snakes (king snakes, milk snakes, and black racers) eat other snakes, including poisonous ones.
Snake venom has been used in developing a variety of human medicines. One type of high blood pressure medicine was developed using information based on chemical secrets contained in snake venom. Researchers are conducting studies using snake poisons in developing treatments for blood and heart problems. Snake venom is also being investigated for controlling some types of harmful bacteria.
Most snakes found in various states are not protected by state law. However, you should check with your local Department of Fish & Wildlife to check on laws in your state. You should obtain a collecting permit from the Department of Fish and Wildlife Resources before attempting to catch and keep a snake. Some snakes are quite rare (Kirtland's snake, copperbelly water snake, Northern pine snake, and scarlet snake) and are being reviewed for the federal government's endangered and threatened wildlife list. The states list several other species as endangered, threatened, or rare. These may include the Eastern coachwhip, green water snake, broad-banded water snake, pygmy rattlesnake, western and eastern ribbon snake, western mud snake, and scarlet king snake.
CONTROLLING SNAKE PROBLEMS
No fumigants or poisons are registered for snake control. Various home remedies, including moth balls, sulfur, lime, cayenne pepper, sticky bird repellent, coal tar and creosote, gourd vines, or musk from king snakes, have not proven effective in deterring snakes. There is a snake repellent registered for rattlesnakes and checkered garter snakes. The active ingredients are naphthalene and sulfur. Three field studies have shown it has limited effectiveness for most species. The only efficient method of discouraging snakes is to modify the environment so they find it unattractive.
You can modify the environment by removing the snake's shelter (hiding places) and its food source (rodents).
Lawns and fields that are kept clean and closely mowed are less attractive to snakes than are areas of tall grass, weeds, brush, and junk. Remove other hiding places such as old boards lying on the ground, rock and junk piles, and trash piles. Trim shrubs and bushes so limbs hang no lower than 12 inches from the ground.
Stack wood for your fireplace or stove away from your home on a rack (not on the ground) that sits at least 12 inches from the ground.
Cleaning around the yard also removes rodent (favorite snake food) habitat. Other suggestions for reducing a snake's food source include placing garbage in sealed trash cans (not bags) away from the house. If you feed pets outside, keep all dog and cat food cleaned up after each feeding and store feed so it is unavailable to rodents (steel trash can).
To summarize, remove rodents, rodent food and shelter, and all objects that create a damp, cool, dark environment preferred by snakes.
Snakes enter buildings in search of cool, damp, dark areas or places where rodents and insects abound. To prevent these unwanted guests from entering your home, check the foundation for cracks and openings 1/4 inch or larger. Use mortar for poured concrete, concrete block, or brick foundations. Use 1/8-inch hardware cloth or sheet metal to seal holes and cracks in wooden buildings. Seal cracks and openings around windows, doors, electrical pipes, and wiring with caulk. If you have an open septic or sump pump drain outside, cover the opening with 1/4-inch hardware cloth. Be sure to check it periodically to ensure that the wire does not interfere with drainage.
If you have young children and live in an area where poisonous snakes are common, you may want to invest in a snake-proof fence. Snake-proof fences are expensive to construct, so fencing an entire yard is not practical. However, you can enclose a small area where young children play.
Snake-proof fences must be constructed of 1/4-inch hardware cloth at least 36 inches wide. The lower six inches must be buried underground, and the fence should be slanted outward at a 30-degree angle. Supporting stakes need to be placed inside the fence. The fence can be made sturdier by attaching wires from the fence to the stakes. All gates must fit tightly; they should open to the inside because of the outward slope of the fence.
Be sure to keep grass and weeds around the fence mowed closely to the ground to prevent snakes from using them to crawl over the fence.
REMOVAL FROM INSIDE A BUILDING
Occasionally homeowners will encounter a snake inside the home, usually in a basement or crawl space. Snakes are attracted to these areas by the warmth on cold days and the cool shade on hot days.
You can increase your chances of capturing a snake in the basement by placing rumpled, damp cloths covered by a dry cloth in areas where snakes have been seen. You can then remove the whole works or capture the snakes individually and remove them. If you are not afraid of snakes, the best way to remove them is to sweep them into a bucket or large garbage can with a broom. NOTE: Homeowners should exercise extreme caution when moving in a crawl space, especially if venomous snakes have been seen in the area. A face bite could be very serious, and even a face-to-face encounter with a racer or rat snake can be an unpleasant experience.
Another very effective method of capturing snakes inside a home or under porches, crawl spaces, or mobile homes is to use a glueboard. These can be purchased in a variety of places such as agriculture supply or hardware stores. Most small snakes can be captured using a single glueboard placed against a wall and away from pipes or other objects a snake could use for leverage to escape.
A more elaborate arrangement is necessary to capture larger snakes. This type of glue trap can be made at home with purchased glueboards. It is constructed of 1/4-inch plywood cut into 16-by-24-inch sections. Drill a 3/4-inch hole in one corner to allow removal of the board by using a hook on the end of a long stick. Fasten two to four glueboards (or use bulk glue) along one side of the plywood board. This type of trap, when placed against a wall, is capable of capturing snakes up to 5 or 6 feet long.
Glueboards should be used only indoors or under structures where children, pets, or other wildlife cannot reach them. The glue is quite messy and hard to remove. Common cooking oil or vegetable oil can be used to remove animals from the glue. Once the unwanted guests have been removed, be sure to close any holes or entrances so the snakes do not return.
Another option is to use the newly developed snake trap called Snake Guard. It should be used like a glueboard.
Another method of capturing snakes is to use a drift fence with a large 5-gallon bucket for the trap. Use 6-inch aluminum flashing 10 feet long for each of the wings. Dig a hole large enough to bury the bucket at ground level. Fill the bucket about one-third full with water or ethanol.
Remember, snakes are an important part of our natural world. The best approach in managing snake problems, where possible, is to leave these animals alone.
Snake Repellent For Snakes
GENERAL FIRST-AID FOR SNAKEBITES
If you or someone with you is bitten by a snake, it is vital to seek appropriate medical treatment. It is equally vital to avoid making inappropriate attempts at treatment, such mistakes can cause more problems than they solve.
In recent years, first aid measures for snakebites have been radically revised to exclude methods that were found to worsen a patient's condition, such as tight (arterial) tourniquets, aggressive wound incisions, and ice. Initial treatment measures should include avoiding excessive activity, immobilizing the bitten extremity, and quickly transporting the victim to the nearest hospital.
What to do in any particular case depends on the circumstances surrounding the bite. If you suspect a snakebite, do the following:
WHAT TO DO
While not all snakebites are life-threatening, it is important to follow these simple steps:
- Remove the victim away from (the snake) danger. Make a mental note of the appearance of the snake. An attempt should be made to identify the type of snake from a safe distance. If you can safely kill the snake, do so and decapitate it. Bury the head (carefully... do not touch it with your hands or exposed body parts) and bring the snake's body with you to the emergency room for identification. The correct anti-venom (antivenin) can then be selected at the hospital. Do not bring the head, however, as even a decapitated snake head can bite up to an hour after its death. However, snake experts recommend not spending time trying to catch the snake to take it to the health care center. So, generally speaking for most people, no attempt should be made to capture or kill the snake. Even if the snake is dead, it should not be picked up with the hands because envenomation by reflex biting after death of the snake has been reported. Also, taking time to kill the snake may delay transportation to medical care, and the snake may bite again. Note the bite mark - venomous snakes will leave 2 distinct puncture wounds, and non-venomous snakes may leave marks resembling more like scratches. See snake bite descriptions on this page for more information.
- Remain calm. If the victim is someone other than yourself, calm him or her). Reassure the victim. Keep them lying down, quiet, and warm. Increased activity improves the flow of venom into the bloodstream. Keep in mind that even if the snake is venomous, a large number of bites from venomous snakes are "dry" (without venom), and even if the venom did penetrate, the death rate from a venomous snake bite is less than 1 percent when modern medical resources are used. With that in mind... do not panic, just get immediate medical assistance.
- Do not give the victim anything to eat or drink. Do not take any medications.
- If possible, call immediately for emergency assistance. Do not wait for symptoms to develop because once the symptoms start, they can progress very rapidly with some types of venom. Activating emergency response is usually done by dialing 9-1-1 by using your cell phone or a land-line telephone. Ask for immediate medical attention (contact health center, hospital or toxicology center). Contacting the nearest medical facility not only allows them to assist in getting help to you as well as valuable information about transporting the victim, but it also allows them to obtain and have available the appropriate anti-venom for when the victim arrives at the emergency room.
- Immobilize the victim's affected extremity, keeping the area below the level of the heart.
- Remove jewelry (or other possible constricting items) from the affected area. Swelling can progress rapidly.
- Gently wash the area with soap and water. Snake venom contains enzymes that can cause extensive local tissue damage.
- Apply a cold, wet cloth or apply ice pack (wrapped in a towel or other insulating fabric) locally over the bite to help ease pain. Be careful not to cause injury by excessive cold when using an ice pack. Never apply ice directly to the affected area. If using an insulated ice pack, apply it 10 to 20 minutes once an hour and then remove it. This can be done up to 6 hours for relief of pain.
- Avoid abrupt movements.
- Watch for signs of shock and treat for shock, as necessary. Monitor the airway, breathing, and circulation (ABCs).
- The use of tourniquet or other compressive measures is NOT recommended (see What Not To Do). After contacting medical emergency, and ONLY if they have recommended it and if the victim is unable to reach medical care within 30 minutes, apply a wide, flat constriction band (such as an ACE bandage) 2 to 4 inches above the fang marks between the bite and the heart to help slow venom and block only superficial venous and lymphatic flow (typically, with about 20 mm Hg pressure) and should be left in place until antivenin therapy, if indicated, is begun. CAUTION: It should not cut off the flow of blood from a veins or artery. A good rule of thumb is to make the band loose enough that a finger or two can slip easily under it since impairment of arterial blood flow could increase tissue death. Upper extremities should be splinted as close to a gravity-neutral position as possible, preferably at heart level. Adjust the band as swelling occurs. Never place a band around a joint, the head, neck, or chest. This constricting band is NOT the same thing as a tourniquet, but should only be used if recommended by an emergency medical professional, otherwise do not use it.
- A venom extractor can be beneficial if applied within five minutes of the bite and left in place for 30 minutes. Suction the bite over the fang marks, using an extractor from a snakebite kit. Suction after 30 minutes is ineffective, the venom has already diffused.
- Get the victim (and the dead snake) to the nearest hospital emergency room as quickly as possible for further treatment.
WHAT NOT TO DO
The list of measures that should be avoided in response to snakebite include:
- Do Not apply a tourniquet. This has been the cause of numerous amputations. It is possible that the application of a tourniquet is more dangerous than the snakebite itself.
- Do Not pack the entire bitten area in ice. This can block circulation and cause injury to tissue, or even gangrene. An ice pack or some cubes wrapped in cloth, applied periodically to the skin, is the maximum you want to use.
- Do Not cut the wound with a knife or razor. No study has shown any benefit in survival or outcome from incision and suction. Older first-aid kits often contain cutters, but excessive bleeding can cause more damage. If you happen to cut an artery, the victim can bleed to death. Unless you are a vascular surgeon, leave the razor blades in your pack.
- Do Not drink alcohol (or give it to the victim).
- Do Not use an electric shock, Taser, stun-gun, cattle prod, or any such device applied to the snakebite. Although electric shock (often with a stun gun) has been a popular treatment for snakebite in developing countries, it should be avoided as it is a potentially hazardous intervention that has never been shown to be effective. All you do is make the victim more miserable, and the venom will not be broken down by the electricity.
- Do Not use your mouth to try to "suck-out" the venom. The average human mouth has so many bacteria in it that infection of the would be almost certain, complicating treatment in the long run. You also do not want any venom in your mouth where it can enter your blood stream. Only use a snakebite venom extractor from a snakebite kit.
Equine-derived antivenin to snake venom is not recommended for the formularies of standard emergency medical services because of the potential for life-threatening allergic reactions from the antivenin and the length of time required for reconstitution (up to 60 minutes). As safer products, such as Crotalidae Polyvalent Immune Fab (Ovine; CroFab), become more commonplace, antivenin administration in the field may become more feasible, especially in remote areas.
Tetanus (Td) injection should be given within 24 hours of the bite if you have not had a tetanus immunization in the last 5 years
SNAKEBITE VENOM & INSECT VENOM KITS
There is one type of snakebite kit that is worthwhile. It is called the Sawyer Extractor, and is available from Sawyer Products. It contains a syringe-like device that does work to suck out venom without requiring you to open the wounds with a tool. This prevents excessive bleeding and contamination of the wound. This kit will probably get out half the venom if it is used quickly (within 5 minutes is recommended). These are available from many sporting goods stores and on the internet generally less than $20. If you are going to be someplace in snake country that is really far from civilization, having one of these kits in your backpack is a necessity. After you use it, transport to the nearest hospital is still required so that proper medical care can be administered.
Sawyer Venom Extractor
If you spend much time outdoors, you may want to purchase a vacuum pump for removing insect venom. A venom extractor called the Lil Sucker is available from International Reforestation Suppliers. It is small enough to fit inside a pocket or purse. If you get stung, it produces a vacuum that sucks the venom out within two minutes. The end of the extractor can also be used to remove a honeybee stinger. For more information about this product, call 800-321-1037. Their website is www.terratech.net.
Other venom extractors are available through these suppliers:
Bites & Stings Online: Bites & Stings Treatment - The Extractor Pump
Preparedness.com: Snake & Insect Venom Extractor
SOME STING & BITE PRODUCTS FROM AMAZON.COM
For more products, use the search box further down on this page.
DIAGNOSIS & TREATMENT
DIAGNOSIS & LAB TESTS
LABORATORY EVALUATION IN SNAKEBITE
Complete blood count with platelets and differential.*
Partial thromboplastin time.*
Fibrin degradation products.*
Blood type and cross match.
Blood urea nitrogen.
Liver function tests.
Arterial blood gas.****
* - Should be performed as soon as possible and repeated within 12 hours.
** - Including free protein, hemoglobin, and myoglobin.
*** - Suggested for patients older than 50 years and patients with a history of heart disease.
**** - Should be tested if any signs or symptoms of respiratory compromise are evident.
CONVENTIONAL MEDICAL TREATMENT
First-aid measures for snakebite include avoiding excessive activity, immobilizing the bitten extremity, and quickly transporting the victim to the nearest hospital.
Patients with snakebite must be admitted to an emergency department, where a poison control center should be contacted immediately. Wounds should be cleaned, and administration of tetanus toxoid or tetanus immune globulin should be considered for under-immunized or non-immunized patients. Patients should be given intravenous fluid, and blood should be drawn from an unaffected extremity. Complete recommendations for laboratory evaluations of snakebite are summarized above. At least 25 percent of snakebites do not result in envenomation. Patients with asymptomatic pit viper bites should be observed for at least 12 hours before discharge. When envenomation does occur, the leading edge of the swelling should be marked, the time of observation recorded, and the circumference of the extremity measured every 30 minutes. If there is no proximal progression of local signs on the extremity and no coagulopathy after 12 hours of clinical observation and serial laboratory examinations, a reliable patient can be sent home.
SEEKING FOLLOW-UP CARE
The patient should be given strict instructions to return to the hospital immediately if any of the following occurs:
- Increase in pain or onset of redness or swelling.
- Bloody or dark urine.
- Nausea or vomiting.
- Shortness of breath.
- Or other symptoms except mild pain at the bite site.
Prophylactic antibiotics are usually not recommended, as the occurrence of wound infection following crotalid envenomation is low (3 percent).
Patients with bites from snakes with neurotoxic venom should be observed for at least 24 hours. A patient with suspected envenomation by the eastern coral snake needs immediate treatment with an appropriate antivenin, and necessary resuscitation measures should be implemented.
ANTIVENIN INDICATIONS & ADMINISTRATION
Equine-derived antivenin to snake venom has been the mainstay of hospital treatment for venomous snakebite for 35 years.20 It is used to treat approximately 75 percent of the venomous snakebites inflicted annually in the United States.5 The majority of snakebite victims in the United States reach a medical facility within 30 minutes to two hours of being bitten and can be given antivenin at an early stage.
For rattlesnake, cottonmouth, and copperhead bites, Antivenin (Crotalidae) Polyvalent (ACP) has been the standard available treatment; however, ACP is known to be highly allergenic because of its equine origin and may pose a greater risk to the patient than the snakebite. In retrospective studies, rates for acute allergic reactions (including hypotension and anaphylaxis) after ACP administration range from 23 to 56 percent, with even higher rates for delayed serum sickness.
The ovine (sheep-derived) antivenin, CroFab, received approval by the U.S. Food and Drug Administration for treatment of snakebites in October 2000; its use is still limited because of availability and expense, but it is likely to soon replace the equine crotalid antivenin. A prospective trial using CroFab reports only a 14.3 percent incidence of acute reaction, and nearly all events were mild to moderate. Experience with CroFab is still too limited to support the conclusion that serious allergic reactions like anaphylaxis will never occur with its administration.
Equine-derived antivenin to snake venom has been the mainstay of hospital treatment for venomous snakebites.
Eastern coral snakebites require Antivenin (Micrurus fulvius). The specific antivenin for exotic snakebites may be acquired from the Arizona Poison and Drug Information Center (520-626-6016). An antivenin index is available from the American Zoo and Aquarium Association (301-562-0777) and the American Association of Poison Control Centers (800-222-1222). A prescription is required to obtain U.S. antivenin, and a permit is needed to import antivenin not held domestically.
Ideally, antivenin is administered within four hours of the snakebite, but it is effective for at least the first 24 hours. Health care providers should be present for antivenin administration, and epinephrine and antihistamines (both histamine H1 and H2 receptor blockers) should be at the bedside.
Performing a skin test with horse serum is a matter of controversy because it delays therapy, has itself caused anaphylaxis and serum sickness, and has been demonstrated to have a 10 to 36 percent false-negative rate and a 33 percent false-positive rate. Some health care providers believe that medicolegal issues mandate that this test be performed before antivenin administration except in extreme emergencies. Other health care providers bypass skin testing altogether, relying instead on premedication with antihistamines and a trial dose of 5 mL of antivenin administered intravenously.
In the event of a significant skin-test reaction, antivenin would be reserved for use in only the most severe cases and should only be given with careful monitoring, hydration, and pre-medication with antihistamines. An alternative to skin testing is to premedicate all patients who will receive equine antivenin. Suggested intravenous antihistamine pretreatment is diphenhydramine (Benadryl), in a dosage of 1 mg per kg, and cimetidine (Tagamet), in a dosage of 6 mg per kg. If signs or symptoms of anaphylaxis develop, the patient should be immediately treated with epinephrine and steroids. Unstable patients (i.e., those with hypotension, severe coagulopathy, respiratory distress) must receive antivenin because no other treatment can reverse the venom's effect.
The unpredictable nature of snakebites often makes assessment and management difficult. Progressive local injury (swelling, ecchymosis), a clinically evident coagulation abnormality, or systemic effects (hypotension, altered mental status) are strong indications for antivenin treatment. Withholding antivenin is recommended in patients with milder envenomations. The decision to use antivenin requires a careful analysis of the risks and benefits.
ADMINISTRATION OF ANTIVENIN
Both ACP and CroFab are provided as dry powders and require reconstitution before administration. Reconstitution can take up to 60 minutes and should be initiated immediately when the patient arrives in the emergency department. ACP can be reconstituted by injecting 10 mL of supplied sterile water diluent into each vial and swirling (not shaking) to mix, or by diluting 10 vials of antivenin in 1 Liter of normal saline. The reconstituted antivenin (amount will vary, depending on amount required) is then diluted in 500 mL of normal saline or 5 percent dextrose in water, and a trial dose of 5 to 10 mL is administered intravenously over five minutes. If no reaction occurs, the rate should be adjusted to give up to 10 vials in the first hour. Additional infusions should be given every two hours until signs and symptoms are resolving.
In contrast, the safer CroFab is given as a large initial dose to control the envenomation, and smaller subsequent doses are given as needed. In one study, a total of three to 12 vials of CroFab were given for initial control, and additional two-vial doses were given at six, 12, and 18 hours.
For any eastern coral snake bite with possible envenomation, three to five vials of Antivenin (Micrurus fulvius) should be administered immediately. If systemic manifestations are present, at least six to 10 vials should be administered. One exception is the Arizona coral snake (Micruroides), which is not associated with human fatality and for which no antivenin exists.
Immediate hypersensitivity reactions to any antivenin should be managed with epinephrine, antihistamines and supportive care to protect the respiratory and cardiovascular systems. Serum sickness, which commonly occurs one to four weeks after administration of antivenin, presents with pruritus, urticaria, fever, and arthralgias. Serum sickness can be successfully treated with systemic steroids.
Although once popular, surgical intervention with fasciotomy for venomous snakebite is now reserved for selected rare cases and should never be performed prophylactically.
Fasciotomy is a surgical procedure where the fascia is cut to relieve tension or pressure (resulting in loss of circulation to an area of tissue or muscle). Fasciotomy is a limb-saving procedure when used to treat acute compartment syndrome. It is also sometimes used to treat chronic compartment stress syndrome. The procedure has a very high rate of success, with the most common problem being accidental damage to a nearby nerve. Complications can also involve the formation of scar tissue after the operation. A thickening of the surgical scars can result in the loss of mobility of the joint involved. This can be addressed through occupational therapy or physical therapy.
In addition to scar formation, there is a possibility that the surgeon may require a skin graft to close the wound. Sometimes when closing the fascia again in another surgical procedure, the muscle is still too large to close it completely. A small bulge is visible, but is not harmful.
The local and systemic effects of crotaline venom closely resemble the signs and symptoms of compartment syndrome and cannot be reliably Diagnosed in an envenomated patient without directly measuring the compartment pressure.
Fasciotomy should only be performed in patients with clinical signs and symptoms of compartment syndrome (i.e., pain on passive stretch, hypoesthesia, tenseness of compartment, and weakness) and hourly, serially measured compartment pressures exceeding 30 mm Hg. These criteria should be present despite elevation of the affected limb and administration of 20 vials of antivenin. In an animal study, the best outcome in subjects with compartment syndrome was achieved with the administration of antivenin alone. In a series of 1,257 cases of extremity bites, only two fasciotomies were necessary.
HOLISTIC HOME TREATMENT & NUTRITIONAL RECOMMENDATIONS
The recommendations for nutritional supplements and herbs outlined below are intended to alleviate pain and hasten healing after appropriate medical care has been administered. They are NOT meant to substitute for medical care.
A poisonous snakebite is a medical emergency. In the United States, treatment is a complex process that may include the administration of antivenin plus fluid and electrolyte replacement, the administration of oxygen, and other supportive measures. If possible, it is wise to call the emergency room and alert them of the situation before your arrival so that the proper antivenin can be ready for treatment as soon as possible.
Snakebite is more likely to be life-threatening for children and for elderly people.
In a life-threatening situation, massive doses of vitamin C may save a patient's life. See Ascorbic Acid Flush.
Most cases of snakebite occur between sunrise and sunset. Snakes are cold-blooded and are more likely to be out then, basking in the warmth of the day.
Carry a walking stick, especially in rattlesnake country. A snake often will strike at the stick first. Use the walking stick or other object to tap the ground in front of you before you step when walking is a tall grassy area.
Non-poisonous snakebites are usually treated with antibiotics in order to prevent infection.
Black Cohosh syrup helps to relieve pain. Take 1/2 to 1 tablespoon of the syrup 3 times daily.
Herbal Remedies: Blue Cohosh Tincture, 100% Organic, 2 fl. oz.
Shaman Shop: Blue Cohosh Extract, 8 fl. oz.
Poultices of Comfrey, Slippery Elm, or White Oak leave and bark can be used. See Using A Poultice for more information.
Herbal Remedies: Comfrey Leaf Herb Skin Poultice, 2.5 oz., With Poultice Mixer, 2 fl. oz.
Comfrey Salve, Plantain poultice, or salve can also be used.
Herbal Remedies: Comfrey Leaf Ointment, Nature's Way, 2 oz.
Herbal Remedies: Black Ointment, Nature's Way, All Natural Wound Ointment, 2 oz.
MoonDragon's Health Therapy: Herbal Ointment Recipes - Healing Wound Salve
Echinacea, taken in tea and/or capsule form, boosts the immune system.
Herbal Remedies: Echinacea Immune Support Tea, Yogi Tea, Certified Organic, 16 Tea Bags.
Herbal Remedies: Echinacea Tincture For Children, Orange Flavor, Alcohol Free, 100% Organic, 1 fl. oz.
Herbal Remedies: Echinacea Root Complex, Nature's Way, 180 Caps
Herbal Remedies: 5-Echinacea Supplement, Vegetarian, Herbal Remedies USA, 1,000 mg, 60 Liquid VCaps
Herbal Remedies: Echinacea Extract, Standardized, Nature's Way, 340 mg, 60 Caps
Herbal Remedies: EchinaGuard Echinacea Supplement Tincture, Nature's Way, 1 fl. oz.
Herbal Remedies: Echinacea Products & Supplements
Olive Leaf extract has antibacterial properties.
Herbal Remedies: Olive Leaf Herb, Nature's Way, 470 mg, 100 Caps
Yellow Dock can be used to alleviate symptoms. Drink one cup of yellow dock tea or take 2 capsules of yellow dock every hour until the symptoms are gone.
Herbal Remedies: Yellow Dock Root, 500 mg, 100 Caps
Herbal Remedies: Yellow Dock Supplement Tincture, 2 fl. oz.
Herbal Remedies: Yellow Dock Supplements & Products
NUTRITIONAL SUPPLEMENT RECOMMENDATIONS
The nutrients and other measures outlined here are intended to alleviate pain and hasten healing after appropriate medical care has been administered. They are not meant to substitute for it.
Unless otherwise specified, the following recommended doses are for those over the age of 18. For a child between 12 and 17 years old, reduce the dose to 3/4 the recommended amount. For a child between 6 and 12 years old, use 1/2 the recommended dose, and for a child under 6, use 1/4 the recommended amount.
NUTRIENTS Supplement Suggested Dosage Comments Helpful Calcium 500 mg every 4 to 6 hours until the pain begins to ease. Helps relieve pain. Acts as a sedative. Use calcium gluconate form.
Calcium Ionic Mineral Supplement, Fully Absorbable, 700 +/- ppm, 16 fl. oz.,
Liquid Calcium W/ConcenTrace, Orange Vanilla, Trace Minerals, 1000 mg, 32 fl. oz.,
Cal-Mag Pre-Chelated Calcium & Magnesium, Vital Earth, 240 Gelcaps
Magnesium 1,000 mg with the first 500 mg of calcium. Works with calcium.
Magnesium Ionic Mineral Supplement, Fully Absorbable, 350 +/- ppm, 16 fl. oz.,
Just An Ounce Calcium & Magnesium Liquid, Almond Flavor, 16 fl. oz.,
Calcium & Magnesium Mineral Complex, 100% Natural, Nature's Way, 500 mg / 250 mg, 250 Caps
Activated Charcoal 8 Tablets or Capsules taken with a large glass of water. If possible, start immediately after being bitten. Do not take with other supplements or medications. A powerful detoxifying agent.
Activated Charcoal Supplement, Nature's Way, 260 mg, 100 Caps
Colloidal Silver Apply topically as directed on label. A powerful antibiotic that reduces inflammation and promotes healing of skin sores and wounds.
Colloidal Silver, Trace Minerals, 8 fl. oz.,
Colloidal Silver Liquid, SilvaSolution, Super Strength Pro 50, 8 fl. oz,
Colloidal Silver, Silva Pro 50 Spray, 2 fl. oz.,
Colloidal Silver Pump Spray, SilvaSolution, 2 fl. oz.,
Colloidal Silver Salve, SilvaSolution, 2 oz.,
Colloidal Silver Liquid, SilvaSolution, 10 ppm, 16 fl. oz.
L-Serine As directed on label, on an empty stomach. Take with water or juice. Do not take with milk. Take with 50 mg Vitamin B-6 and 100 mg Vitamin C for better absorption. Helps maintain a healthy immune system and aids in the production of antibodies. Multi-Vitamin & Mineral Complex As directed on label. All nutrients are needed to maintain a balance of all essential nutrients for healing, for immune response and to promote health.
Super Multi-Vitamin & Multi-Mineral, Pure Vital Earth, 32 fl. oz. (98% Bio-Available for Absorption),
Damage Control Master Formula, High Potency, Multi-Vitamin & Mineral, 60 Packets (30 Day Supply),
Multi-Vitamin With Minerals, Hi-Tech, 90 Tabs,
Liquid Multi-Vitamin & Mineral Complex With Trace Minerals, Orange Mango, 32 fl. oz.,
Liquid Multi-Vita-Mineral, Strawberry Raspberry, Trace Minerals, 32 fl. oz.,
Multi-Vitamin & Mineral Complete, Trace Minerals, 120 Tabs,
Maxi Multi-Liquid Vitamin With Trace Minerals, 32 fl. oz.,
Alive! Whole Food Energizer, Liquid Multi-Vitamin & Trace Minerals, Citrus Flavor, Nature's Way, 30 oz.,
Hypo-Allergenic Multiple Vitamin & Mineral, Nutribiotic, 180 Caps
Vitamin B-5 (Pantothenic Acid)
500 mg every 4 hours for 2 days. Has anti-allergenic and anti-stress properties.
Vitamin B-5 (Pantothenic Acid), Nature's Way, 250 mg, 100 Caps
As directed on label. Stimulates and detoxifies the organs and blood.
Ultimate Cleanse, 2-Part Internal Cleansing Program, Includes 2 Free CD's, Nature's Secret, 240 Tabs
Vitamin A 10,000 IU daily. If you are pregnant, do not exceed 10,000 IU daily. Enhances immunity and protects the body from bacteria.
Vitamin A, 10,000 IU, 100% Natural, Nature's Way, 100 Softgels,
Vitamin A, Fish Liver Oil, NOW Foods, 25,000 IU, 250 Softgels,
Dry Vitamin A & D, Nature's Way, 15,000 IU / 400 IU, 100 Caps,
Shark Liver Oil With Vitamin A, NOW Foods, 400 mg / 10,000 IU, 120 Softgels
As directed on label. Powerful antioxidants that boost the immune system.
Beta Carotene (Natural Dunaliella Salina), Nature's Way, 100% Natural, 25,000 IU, 100 Softgels,
Multi-Carotene Antioxidant, Nature's Way, 60 Softgels
Vitamin C With Bioflavonoids 1,000 mg every hour until pain and swelling subside. Aids in detoxifying the venom and eliminating it from the body. Very important in crisis allergy situations.
Vitamin C Liquid w/ Rose Hips & Bioflavonoids, Kosher, Natural Citrus Flavor, Dynamic Health, 1000 mg, 16 fl. oz.,
Ester C With Bioflavonoids, Nature's Way, 1000 mg, 90 Tabs,
Vitamin C 1000 With Bioflavonoids, Nature's Way, 100% Natural, 1000 mg, 250 VCaps,
The Right C, Nature's Way, 1000 mg, 120 Tabs
Vitamin E Apply topically to the affected area 3 to 4 times daily. 200 IU taken internally daily. Promotes tissue healing and enhances immunity.
Ester E Natural Vitamin E, California Natural, 400 IU, 60 Softgels,
Vitamin E, 400 IU, 100% Natural, NOW Foods, 100 Gels,
Vitamin E-1000, NOW Foods, 1000 IU, 100 Gels,
Vitamin E, d-alpha-tocopherol, 400 IU, 100 Softgels
Zinc 30 mg daily. Do not exceed a total of 100 mg daily from all supplements. Boosts immune response and function. Use zinc gluconate lozenges or OptiZinc for best absorption.
Zinc Ionic Mineral Supplement, Fully Absorbable, 100 +/- ppm, 16 fl. oz.,
Colloidal Silver & Zinc Lozenges, Silva Solution, 90 Lozenges,
Zinc Lozenges W/ Echinacea & Vitamin C, Nature's Way, 23 mg, 60 Lozenges,
Zinc Ionic Mineral Supplement, Fully Absorbable, 100 +/- ppm, 16 fl. oz.,
Zinc (Chelated), 100% Natural, Nature's Way, 30 mg, 100 Caps
SNAKEBITES & LIZARD BITE SUPPLEMENTS & PRODUCTS
Information, supplements and products for snakebites and lizard bites to help heal wounds after receiving medical treatment.
Activated Charcoal Supplement, Nature's Way, 260 mg, 100 Caps
Nature's Way Activated charcoal supplement captures unwanted material of gas and carries it safely through the digestive system.
Alive! Whole Food Energizer Multi-Vitamin Mineral With Naturally Occurring Iron (No Iron Added), Nature's Way, 180 Tabs
No other supplement contains more life-giving nutrients than Nature's Way Alive. This supplements is better absorbed into your blood stream because its tablets disintegrate up to 5X faster than other leading brands.
Colloidal Silver & Zinc Lozenges, SilvaSolution, 90 Lozenges
Now you can get powerful liquid silver in the most convenient form ever with new Silva Solution Silver and Zinc Lozenges.
Colloidal Silver Lotion, SilvaSolution, Homeopathic, 4 fl. oz.
Effective for minor skin irritations, rashes hives, insect bites, sores, burns, inflammation, skin swelling and dry, itchy, cracked skin.
Comfrey Leaf Powder, 4 oz. Bulk
One of the most well-known healing plants, especially for its ability to heal tissue and bone.
Comfrey Leaf Ointment, Nature's Way, 2 oz.
Comfrey Leaf Ointment is a 100% all natural, mild scented herbal ointment.
Cyani (Centaurea Cyanus) Tincture, 2 fl. oz.
Considered by the Plains Indians as an antidote for snake bites, insect bites and stings. Beneficial for nervous disorders, infections, eye disorders, and mouth sores/ulcers.
Just An Ounce Liquid Calcium & Magnesium, Almond Flavor, 16 fl. oz.
Just An Ounce, Calcium and Magnesium Liquid can help with the development of strong bones and teeth, also prevents muscle cramping, risk of colon cancer, maintain regular heart beat, protects against osteoporosis and helps relax the central nervous system.
Pantothenic Acid, 100% Natural Vitamin B-5, Nature's Way, 250 mg, 100 Caps
Nature's Way Pantothenic Acid, Vitamin B5, is 100% natural calcium pantothenate. It contains no artificial ingredients or preservatives.
Calendula Cream, Nelson's Bach, Organic, 30 g / 1 oz.
Nelson's Bach Calendula cream is a soothing multi-purpose skin cream, especially prepared from the Calendula which offers soothing relief for rough, dry, irritated or chapped skin. Helps to restore healthy skin texture. Made with organically grown Calendula officinalis which provides relief for burns, and is gentle enough for rashes and chafing on babies sensitive skin. Directions: Check that the tube seal is not broken before first use. Pierce tube seal with point in tip of cap before first use. Apply the cream to the affected area & rub in lightly. Warnings: For external use only.
Echinacea Herb, Nature's Way, 400 mg, 180 Caps
Echinacea herb supports the immune system and promotes general well-being in cold and flu season.
Goldenseal Root Tincture (Hydrastis Canadensis), 100% Organic, 2 fl. oz.
Goldenseal is an antibacterial and antiseptic. Use especially when mucus turns thick and discolored. Use short term only with other herbs.
Olive Leaf With Echinacea & Vitamin C, 100 Caps
Olive Leaf with Echinacea and Vitamin C represents the powerful synergy of current scientific research and traditional herbal medicine.
Grape Seed Extract, Standardized, Nature's Way, 100 mg, 30 Caps
Nature's Way Standardized Grape Seed Extract are technically and scientifically advanced herbal product.
Tea Tree Antiseptic Cream, 4 fl. oz.
This tea tree cream has a soothing and cooling effect on inflamed skin. It can be used as diaper change lotion.
Tea Tree Antiseptic Cream, Bulk, 1 Gallon
This tea tree cream has a soothing and cooling effect on inflamed skin. It can be massaged into sore joints for relief from discomfort.
Tea Tree Oil Antiseptic Ointment, 2 oz.
A 100% natural Tea Tree Oil antiseptic ointment that combines a therapeutic dose of pure tea tree oil with the absorption powers of Australian Eucalyptus australiana oil and lavender oil. This Tea Tree Oil antiseptic ointment is an ideal treatment to protect and treat cuts, abrasions, chafing rashes and other skin irritations. Directions: Apply 2-3 times daily to minor rashes, cuts, abrasions, sunburn and insect bites. Its natural base of oils and beeswax repels water to protect the area. Avoid contact with eyes. Discontinue use if irritation develops. Keep out of reach of children. For external use only.
Tea Tree Oil Antiseptic Solution (15% Water Soluble), 2 fl. oz.
Tea Tree Oil Antiseptic Solution can be used for mixing with water for douching, athletes foot, facial problems, and bathing. Use Tea Tree Oil Antiseptic Solution when full strength tea tree oil is not necessary. Directions: For use a mild natural antiseptic. Apply full strength to cuts, abrasions, insect bites and stings. May be diluted with 1 to 10 parts water. This product is water soluble.
Tea Tree Essential Oil, 100% Pure, NOW Foods, 1 fl. oz.
Tea Tree Essential Oil can be used externally as a completely natural germicide and fungicide. Our Tea Tree Essential Oil can be applied directly to the site of infection or irritation, such as pimples, boils, cuts, insect bites and minor burns.
Tea Tree Oil Bulk (Malaleuca Alternifolia), 32 fl. oz.
Bulk Tea Tree Oil can be used for so many things including cuts, burns, abrasions, insect bites, bee stings, rashes, impetigo, boils, sinus problems, sore throat, thrush, fingernail and toenail infections.
Tea Tree Oil (Malaleuca Alternifolia), 100% Pure Oil, NOW Foods, 2 fl. oz.
Tea Tree Oil can be used for general first aid uses such as cuts, burns, abrasions, insect bites, bee stings, rashes, impetigo, boils, sinus problems, sore throat, thrush, fingernail and toenail infections.
Vitamin C 500 With Rosehips, Nature's Way, 100% Natural, 500 mg, 250 VCaps
Nature's Way Vitamin C with Rosehips offers a rich whole plant source of vitamin C.
Vitamin C 1000 With Bioflavonoids, Nature's Way, 100% Natural, 1000 mg, 250 VCaps
Nature's Way Vitamin C with Bioflavonoids provides antioxidant protection for many of the body's important enzyme systems.
Vitamin E 400, 100% Vegetarian, Nature's Way, 400 IU, 100 Liquid VCaps
Nature's Way Vitamin C is a 100% Vegetarian dietary supplement. Natural Vitamin E as d-alpha tocopherol is a powerful antioxidant that combats damaging free radicals. It also prevents oxidation of LDL cholesterol.
Zinc Lozenges With Echinacea & Vitamin C, Nature's Way, 23 mg, 60 Lozenges
Nature's Way Zinc lozenge boosts cold season defense with zinc, widely recognized as an important nutritional support during the cold season, and echinacea pupurea, clinically shown to support the immune system, and Vitamin C, a vitally important vitamin for general health maintenance.
FOR A COMPLETE LIST OF INFLAMMATION SUPPLEMENTS & PRODUCTS:
Herbal Remedies: Snakebite & Lizard Bite Supplements & Products
Herbal Remedies: Insect Bite / Sting Information
Herbal Remedies: Insect Bite / Sting Supplements & Products
Herbal Remedies: Inflammation Information
Herbal Remedies: Inflammation Supplements & Products
Herbal Remedies: Insect Allergy Information
Herbal Remedies: Insect Allergy Supplements & Products
Herbal Remedies: Bee Sting Information
Herbal Remedies: Mosquito Bite Supplements, Information & Products
Herbal Remedies: Spider Bites Supplements, Information & Products
NOTIFY YOUR HEALTH CARE PROVIDER IF...
You have suspected or confirmed case of snake bite and need to receive medical care.
You have side effects associated with medications given for treatment of snakebite or any other unexpected or unexplained symptoms.
You develop secondary infection that needs to be treated with antibiotics or other medications.
You need a Tetanus booster shot.
HELPFUL RELATED LINKS
MoonDragon's Health & Wellness: Allergies
MoonDragon's Health & Wellness: Insect Allergy
MoonDragon's Health & Wellness: Bee Sting
MoonDragon's Health & Wellness: Insect Bite
MoonDragon's Health & Wellness: Spider Bite
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Prescription for Nutritional Healing: The A-To-Z Guide To Supplements
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SELECTED SNAKEBITE REFERENCES
1. Weed HG. Nonvenomous snakebite in Massachusetts: Prophylactic antibiotics are unnecessary. Ann Emerg Med 1993;22:220-224.
2. Blaylock RS. Antibiotic use and infection in snakebite victims. S Afr Med J 1999;89;874-876.
3. Watson WA, Litovitz TL, Rodgers GC Jr, et al. 2002 annual report of the American Association of Poison Control Centers Toxic Exposure Surveillance System. Am J Emerg Med 2003;21:353-421.
4. Gold, BS, Barish RA, Dart RC. North American snake envenomation: Diagnosis, treatment and management. Emerg Med Clinics N Amer 2004;22: 423-443.
5. Chippaux JP. Snake-bites: Appraisal of the global situation. Bull World Health Organ 1998;76:515-524.
6. Wingert WA, Chan L. Rattlesnake bites in southern California and rationale for recommended treatment. West J Med 1988;148:37-44.
7. Norris RL, Bush S. North American venomous reptile bites. In: Auerbach PS, ed. Wilderness Medicine, 4th ed. St. Louis: Mosby Inc;2001:896-926.
8. Gopalakrishnakone P, Hagwood BJ, Holbrooke SE, et al. Sites of action of Mojave toxin isolated from the venom of the Mojave rattlesnake. Br J Pharmacol 1980;69:421-431.
9. Parrish HM. Incidence of treated snakebites in the United States. Public Health Rep 1966;81:269-275.
10. Whitley RE. Conservative treatment of copperhead snakebites without antivenin. J Trauma 1996;41:219-221.
11. Kitchens CS, Van Mierop LHS. Envenomation by the eastern coral snake (Micrurus fulvius fulvius): A study of 39 victims. JAMA 1987;258: 1615-1618.
12. Kitchens CS. Hemostatic aspects of envenomation by North American snakes. Hematol Oncol Clin North Am 1992;6:1189-1195.
13. Fix JD. Venom yield of the North American coral snake and its clinical significance. South Med J 1980;73:737-738.
14. Wingert WA, Wainschel J. Diagnosis and management of envenomation by poisonous snakes. South Med J 1975;68:1015-1026.
15. Gold BS, Wingert WA. Snake venom poisoning in the United States: A review of therapeutic practice. South Med J 1994;87:579-589.
16. Norris RL, Minton SA. Non-North American venomous reptile bites. In: Auerbach PS, ed. Wilderness Medicine, 4th ed. St. Louis: Mosby Inc; 2001: 927-951.
17. Jenkins M, Russell FE. Physical therapy for snake venom poisoning. Phys Ther 1974;54:1298-1304.
18. Russell FE. AIDS, cancer, and snakebite-what do these three have in common? West J Med 1988;148:84-89.
19. Minton SA. Bites by non-native venomous snakes in the United States. Wilderness Environ Med 1996;7:297-303.
20. De Haro L, Pommier P. Envenomation: A real risk of keeping exotic house pets. Vet Hum Toxicol 2003;45:214-216.
21. Silveria PV, Nishioka C de A. Non-Venomous snake bite and snake bite without envenoming in a Brazilian teaching hospital. Analysis of 91 cases. Rev Inst Med Trop Sao Paulo 1992;34:499-503.
22. Davidson TM, Schafer SF. Rattlesnake bites. Guidelines for aggressive treatment. Postgrad Med 1994;96:107-114.
23. Horowitz RS, Dart RC. Anitvenins and immunobiologicals: Immunotherapeutics of envenomation. In: Auerbach PS, ed. Wilderness Medicine, 4th ed. St. Louis: Mosby Inc; 2001: 952-960.
24. Sullivan JB. Past, present, and future immunotherapy of snake venom poisoning. Ann Emerg Med 1987;16:938-944.
25. Jurkovich GJ, Luterman A, McCullar K, et al. Complications of Crotalidae antivenin therapy. J Trauma 1988;28:1032-1037.
26. Consroe P, Egen NB, Russell FE, et al. Comparison of a new ovine antigen binding fragment (Fab) antivenin for United States Crotalidae with the commercial antivenin for protection against venom-induced lethality in mice. Am J Trop Med Hyg 1995;53:507-510.
27. Offerman SR, Bush SP, Moynihan JA, et al. Crotaline Fab antivenom for the treatment of children with rattlesnake envenomation. Pediatrics 2002;110: 968-971.
28. Boyer LV, Seifert SA, Cain JS. Recurrence phenomena after immunoglobulin therapy for snake envenomations: Part 2. Guidelines for clinical management with crotaline Fab antivenom. Ann Emerg Med 2001;37:196-201.
29. Lavonas EJ, Gerado CJ, O'Malley G, et al. Initial experience with Crotalidae polyvalent immune Fab (ovine) antivenom in the treatment of copperhead snakebite. Ann Emerg Med 2004;43:200-206.
30. Bush SP, Green SM, Moynihan JA, et al. Crotalidae polyvalent immune Fab (ovine) antivenom is efficacious for envenomations by Southern Pacific rattlesnakes (Crotalus helleri). Ann Emerg Med 2002;40:619-624.