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Snake Venom

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Date added: 17-09-21


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Intro “Each year around 1 million people world wide are bitten by snakes, and around 30,000 to 40,000 of the snake bite victims die from the venomous injection of a venomous snake. Of the 2,000 species of snakes, about 400 are venomous. The cobra, coral snake, and rattlesnake are common examples of venomous snakes. ” (Snake2). Knowing this information and more can possibly save yours or somebody else’s life when put into a situation when you have been bitten by a snake and can’t identify it, this paper will educate you on what to do in case of a snake bite and how the venom works on the human body. Snake bite- “the wound made by the fangs of a venomous snake or the teeth of a non-venomous one. ” (Snakebite). Snakes only bite to capture prey or protect themselves when they feel threatened. When they feel threatened they give you warnings to tell you that they are about to strike. For example a rattlesnake will shake its rattle, a cobra will raise its hood, and the majority of the snake world will warn you with a loud audible hiss. Ways of Envomation “The process of introducing venom into a victim is called envenomating. Envenomating by snakes is most often through their bite, but some species, like the spitting cobra, use additional methods such as squirting venom onto the mucous membranes (eyes, nose, and mouth) of prey animals. ” (Reptipage 1). There are different types of delivery methods of delivery of venom. First you come to the short fixed fangs of cobras and mambas. These fangs are fixed in the front of the snakes mouth and do not move when envenomating. In exception for the cobras there is the spitting cobra, which shoots out a jet of venom out of the hollow holes in the fangs. The snake usually aims for the eyes, nose, or mouth as mentioned above. Then we come to the vipers, which have swiveling fangs, which swing forward like a hinge while striking. Then there are the rear fanged snakes, which most of them are in the colibrid family. These fascinating snakes have fixed fangs in the back of their mouth, which are actually just enlargened teeth, the strangest of these snakes in the stiletto snake. When the snake goes to strike, the fangs slide out of the side of the mouth and the snake strikes with the side of its mouth. It smacks its head on the victim and the fangs pierce the victim from the side of the mouth. When the snake bites, it chews to get venom flowing. Most of the snakes in this family are mildly venomous and the power of the venom isn’t strong enough to do any real harm. Venom “Venoms are basically modified digestive juices, with a clear or yellowish tint to it. The components of venom cause the prey’s nervous system to malfunction while others break down muscles and blood vessels. Most venoms cause a multitude of effects that work in concert to paralyze and kill. The snake stores the venom in glands behind each eye that connect with enlargened teeth modified for injection. ” (Harvey 10). The Action of Venom “Snake venom is a complex protein substance and its exact composition varies from one species of snake to anther. When a snake bites, it generally injects its venom though or near its fangs into the wound. Snakebite can even occur when the snake has been dead recently, or even by the snakes dismembered head because the snakes nerve reflexes are not extinguished for many hours. ” (Snakebite 2). A neurotoxin venom works to disrupt the function of the brain and nervous system. Classically, such snake venom causes paralysis or lack of muscle control, but it can also disrupt the individual signals sent between neurons and muscles. Such venoms can also attack the body’s supply of ATP, a nucleotide that is critical in energy transfer. Researchers once believed that many snake venoms contained digestive enzymes to make it easier to process prey. However, this does not appear to be the case; snakes with digestive enzymes in their venom don’t digest prey any more quickly. More probably, such snake venom contributes to tissue death by literally eating the tissue away, accomplishing the snakes goal of incapacitating a victim long enough to start eating. Some animals have natural immunities to snake venom and immunities can also be induced through careful applications of processing the venom. This technique is used to make the venom used in snakebite treatments. Because there are around 600 venomous snakes in the world, many nations have venom exchange programs, which ensure that hospitals and treatment centers can provide anti-venom from other facilities in an emergency. (Snakebite 1). Venom Composition “Snake venom has a great majority of proteins: some have enzymatic activity, some can block nerve or muscle cell receptors, and some have activity in the protein cascades for coagulation, complement fixation, or inflammation. ” (Reptipage 1). “Most snake venoms contain specific proteins that paralyze the prey so that it no longer moves, interfere with normal blood clotting mechanisms so that the anima goes into shack and then they begin the process of digestion by breaking down the tissues of the prey animal. ” (Reptipage 1). Toxicity (LD 50) Toxicity of venoms is usually expressed by LD50: the lowest dose that kills 50% of a group of experimental animals. That dose varies not just between the venoms tested, but also depends on which species of prey animals receive the venom. Generally, the most toxic venom is the one with the lowest LD50. However, some snakes have venoms that are quite specialized for certain types of prey. Few studies have used the natural prey of a snake species, which would involve capturing a number of wild animals. Instead most research has used inbred strains of laboratory animals. Human susceptibility to snake venom is generally estimated from the LD50 for rodents. The next factor in assessing the danger of a partiticular species of snake is the dose of venom that is actually introduced into the tissues. Some types of snakes have an extremely efficient mechanism of injection venom with a sing strike; others have poor success in doing so. The amount of venom produced by snakes that is available for secretion with a bite also varies between kinds of snakes, and between individuals (usually by size) of any one species” (reptipage 1). Symptoms of venomous snakebites. The symptoms vary not only with the type of venom injected, but also with the amount. A snake may release no venom at all, or it may release as much as 75% of the total amount stored in its venom glands. Often when a snake bites in self-defense, it injects less venom than when it attacks its prey. The physical condition of the victim and the location of the bite also affect the severity of the symptoms. A bite into a muscle is less dangerous than a bite into a blood vessel, for example, because toxins in the blood are quickly circulated through the body. General symptoms of snakebite include localized pain and swelling soon after the bite occurs, followed by nausea, tingling or numbness, weakness, and shortness of breath. If victims do not receive treatment within a few hours, they may suffer convulsions, fall into a coma, and die. Even venoms that damage only tissue can be fatal within several days. ” (Snake venom 2). Listed below are different stages of snakebite symptoms: Paralysis “Some proteins secreted in snake venoms are toxins that affect nerves. (Neurotoxins) and the contractibility of muscle. Most neurotoxins in snake venoms are too large to cross the blood-brain barrier, and so they usually exert their effects on the peripheral nervous system rather than directly on the brain and spinal cord. Many of these neurotoxins cause paralysis by blocking the neuromuscular junction. In fact, biologists first learned some of the details of how the neuromuscular junction normally functions by using purified snake venoms in physiology experiments. ” (Reptipage 2). Shock “Many components in snake venom disrupt normal blood flow and normal blood clotting (coagulation). Some common enzymes in snake venoms increase bleeding by preventing the formation of clots, and others by breaking down established clots. Both of these types of enzymes include metalloproteases. Other toxins increase ‘bleeding time’ by inhibiting the aggregation of platelets, the small odd-shaped blood cells that collect at the site of a tear in a blood vessel and form a plug to close it. Profound loss of blood can cause hemorrhagic shock, and disable a prey animal. When many tiny blood clots form in the bloodstream there is a pathological condition known as disseminated intravascular coagulation (DIC), which also causes shock. Some enzymes in snake venom set of DIC in the bloodstream of their envenomated prey by interfering with the activity of serine proteases involved in the regulation of hemostasis. ” (Reptipage 2”). Infarction (stoke and heart attack) “Toxins that set off clotting within the blood vessels of envenomated animals can cause both stroke and heart attacks. Infarction is a medical term that means death to tissues because of a block in their blood supply, and clots within the arteries of the neck and brain, as well as the coronary arteries can deprive the blood supply enough to cause infarctions in these organs. (Reptipage 3). Death!!!! When the circumstances are right, and enough venom is injected, if you do not receive medical attention immediately after the bite, you will DIE! Types of venomous snakes There are two major types of venomous snakes: 1. Vipers and 2. Elapids. Vipers include rattlesnakes, copperhead, and water moccasins. Many vipers strike and release their victims quickly because their fangs can shoot venom instantly into the wound. Elapids include cobras, mambas, and coral snakes. The fangs of an elapid snake do not deliver venom quickly; therefore, an elapid frequently hangs on to its victim and chews, forcing venom into the bite. In most cases, the wound from an elapid causes little pain at first. But later the breathing organs of the victim become partly paralyzed, and the victim becomes sleepy. Venom characteristics and venom delivery (according to family) The venomous snakes are represented in only four families. There are variations in the methods of envenomation according to family. The families are listed below with information included about each of them. Crotalinae (crotalines) “ Common names of well-known members: Pit vipers, including lanceheads, moccasins, and rattlesnakes. “Pit viper venom characteristically contains a potent mix of enzymes that produce an emphatic degree of tissue destruction at the site of the bite. As with most venom, there can be both local and systematic effects. However, unless a bite by a pit viper is “dry” (meaning no venom injected), there will ordinarily be marked inflammation at the site of the bite and possibly systemic effects. Rattlesnakes range in size from small pigmy rattlesnakes (sistrurus) to large (many species of crotalus, such as the Eastern diamondback, (crotalus adamanteus) most pit vipers are potentially very active and aggressive snakes. The strike can be lightning quick, measured in one study as less than 50ms. ” (Reptipage 2). Viperidae (viperids) Common names of well know members: pitless vipers, pit vipers “Bites by snakes of the family viperidae often induce local break down of muscle and tissues which may result in permanent deformity in the region of the bite (myotoxic phospholipases). Some types of vipers inject venom that travels through the blood stream and breaks down muscle cells systemically, with relatively little reaction at the site of the bite, but enough muscle cells throughout the body release their contents into the victim’s bloodstream to cause a condition know as rhabdomyolysis. In rhabdomyolysis (rhabdo=rod, myo=muscle cell, lysis=breaks apart) the large iron containing protein, myoglobin, is released into the circulation (myoglobulinemia). When myoglobin reaches the kidney, the renal system attempts to filter it out of the blood. If the amount of myoglobin is very large, acute renal failure results, and the blood is no longer properly filtered of even normal body wastes by the kidneys. The common names of vipers frequently fail to identify an actual species. For example, the name, rock viper, refers to two entirely different kinds of snakes. ” (Reptipage 2). Elapidae (elapids) Common names of well-known members: cobras, kraits, coral snakes, mambas, sea snakes, sea kraits, and Australian elapids “The venom of elapid snakes is notorious for the potency of its neurotoxins. These snakes have similarities in their venom compared to Vipers. Venomous elapid snakes greatly range in size, aggressiveness and in habitat. ” (Snake bite 2). For example the king cobra (ophiophagus Hannah) is the world’s longest venomous snake, growing up to 5. 5m. (18. 5 ft. ) And the Coral Snake only grows to a maximum of 2 ft. “The main constituent of king cobra venom is a postsynaptic neurotoxin, and a single bite can deliver up to 400-500 mg. Of venom, about fifteen thousand times the LD50 dose for mice. The world’s most venomous snake is the Australian elapid: the small-scaled snake (oxyuranus micolepidotuscan) delivers up to 100 mg. Of venom with an LD50 dose of 0. 01 mg. kg) 1 giving it up to 500,000 LD50mice doses. Although sea snakes have some of the world’s most potent venom, the numbers of human fatalities from snakebites is apparently limited by their marine environment and behavior. For prey animals and in cases of defensive behavior towards humans, “neuromuscular paralysis usually occurs with elapid (cobra, krait, and mamba) envenomation”, however, many elapid snakes have venoms that also include toxins that cause bleeding. For example the venom of all contain metalloproteinases that interfere with platelet aggregation. Besides neurotoxins and metalloproteinsases, there are additional types of bioactive proteins and polypeptides that are common in elapid venom. A second group of toxins are cell membrane poisons that act in a general fashion, but their chief effect is on the heart, producing arrhythmias and impaired contractility. The third group of toxins contains enzymes that break down protein and connective tissue. These necrosis producing toxins are typical of the venom from the spitting cobras (naja spp. ) of Africa, china and Sumatra” (Reptipage 2). Colubridea (colubrids) Common well known members: boomslang This family of snakes contains about 2/3 of all living species of snakes. A minority has somewhat enlargened-grooved teeth at the back of the upper jaw for delivering venom under low pressure. This unsophisticated system for venom delivery makes it more difficult for scientists to collect colubrid venom for chemical studies than the venom from vipers and most elapids, which inject venom through front fangs under higher pressure. Often, colubrid venoms were collected only in relatively small quantities and with impurities from other mouth contents from the snake. As more recent collection methods have been devised that overcome some of these problems, researchers have discovered that earlier assumptions about the venom contents were sometimes mistaken. For example, phospholipase A2 (PLA2), which had been thought to be lacking in venoms in this family has now been detected in at least two species. Some venoms show high toxiticity toward mice, and others are toxic to birds and/or frogs only. Because many colubrids feed on non-mammalian prey, lethal toxicity toward mice is probably only relevant as a measure of risk posed to humans. At least five species (dispholidus typus, thelotormis capensis, rhabdophis tigrinus, philodryas olfersii, and tachymenis peruviana) have caused human fatalities. ” (Snakebite 3). Atractaspididae Common names: Mole vipers, stiletto snakes, burrowing asps. “The Atractaspididae are a family of snakes found in Africa and the Middle East. Currently, 12 genera are recognized. No full experiments have been conducted on this specific species of snakes, but it is understood that the venom of the group is extremely virulent. ” (Wikipedia) “This family includes many genera formerly classed in other families, on the basis of fang type. It includes fangless (aglyphous), rear-fanged (opisthoglyphous), fixed-fanged (proteroglyphous), and viper-like (solenoglyphous) species. Molecular and physiological data linking this family to others is ambiguous and often contradictory, which means the taxonomy of this family is highly contentious. The nominate family, Atractaspididae has itself been moved to and from other taxa, reinforcing the ambiguity of this family. ” (Wikipedia 8). Treatment If a snakebites you, call an ambulance and if possible, identify the type of snake that made the bite. Position your self or the victim so that they are comfortable. Keep calm and try to get your heart beating fast because it only spreads the venom more quickly. Tie a band above the bite. Make sure that the band fits snug with the skin, but loose enough that a finger can be easily placed under it. Do not loosen the band until medical assistance arrives. The victim can drink water unless nausea develops. Do not give the victim aspirin, or any drug containing aspirin. Also do not give the victim any alcoholic drink, or any other form of alcohol. Do not attempt to administer anti-venom by your self or to cut the wound and suck out the venom. This does not help! Conclusion Snakes are not cold-blooded killers (although they are cold blooded) like the movies portray them to be. They only attack in defense and when obtaining food. If you happen to be bitten by a venomous snake, seek immediate medical attention. There are 4 basic groups of venomous snakes: crotalines, viperids, elapids, and colubrids. This information given in the report can possibly save yours, or somebody else’s life in a given situation.
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