Envenomation snake

Two phenomena of reptilian prey searching are well investigated responses of various snakes to the odors of invertebrates, and rattlesnakes trailing of envenomated small mammals. 

The rattlesnake C. viridis searches for the particular odor it had experienced when striking the prey. In one experiment, snakes were induced to strike perfume-treated mice. Then they were exposed to perfumed, but non-envenomated, carcasses. The snakes preferred a carcass with the same odor as the originally struck mouse. In a second experiment, snakes preferred the carcasses of mice on the same diet as the ones they had struck. Thus rattlesnakes form a... 

Howarth DM, Southee AE, Whyte IM. Lymphatic flow rates and first-aid in simulated peripheral snake or spider envenomation. Med J Australia 1994 161(11-12) 695-700. 

Snake bite (pit vipers) Antivenin (Crotalidae) polyvalent, equine The entire dose should be given within 4 hours after the bite by the IV or IM route (1 vial = 10 mL) Minimal envenomation 2-4 vials Moderate envenomation 5-9 vials Severe envenomation 10-15 vials Additional doses may be required. Neutralizes the venom of rattlesnakes, copperheads, cottonmouths, water moccasins, and tropical and Asiatic crotalids. Serum sickness occurs in almost all patients who receive > 7 vials. 

Features of Envenoming from Bites of Snakes Producing Venoms Containing... 

Presynaptic snake neurotoxins endowed with PLA2 activity (SPANs) are major components of the venom of four families of venomous snakes (Crotalidae, Elapidae, Hydrophiidae, and Viperidae). These neurotoxins play a crucial role in envenomation of the prey (Harris 1997) by causing a persistent blockade of neurotransmitter release from nerve terminals with a peripheral paralysis very similar to that of botulism (Connolly et al. 1995 Gutidrrez et al. 2006 Kularatne 2002 Prasampun et al. 2005 Theakston et al. 1990 Trevett et al. 1995 Warrell et al. 1983). 

There is no accurate estimation of the incidence and number of deaths caused by snake bites in the world. It is possible that tens of thousands of individuals die each year following snake envenomation in Asia, which is the most affected area (Guti6rrez et al. 2006). The death rate has strongly decreased in Australia... 

This family includes coral snakes, cobras, mambas, and kraits. In the United States, Elapidae are responsible for 1-2% of poisonous snakebites. The incidence of envenomations is greater in some other parts of the world. Examples of coral snakes commonly found in the United States are the eastern coral snake, the Sonoran coral snake, and the Texas coral snake. Coral snakes are smaller than pit vipers. They do not have facial pits, and the head is rounded, as are the pupils. Eangs are 2mm and fixed to the jaw. Coral snakes are also more brightly colored, with bands of black and red, separated by yellow and white bands. Coral snakes are timid, nocturnal creatures. 

Envenomation from a coral snake exerts minimal local pain, and appears as rows of teeth marks. Victims may report that the snake was chewing on the bite site and had to be forcibly removed. Coral snake venom is composed of peptides and enzymes that have not all been identified, but which exert neurotoxicity rather than cytotoxicity. 

Relative to treatment of snake, spider, scorpion, and other terrestrial animal envenomatlons, the treatment of most envenomatlons due to marine animals is rather primitive. This is primarily due to our knowledge of these venoms being less complete. The incidence of jellyfish envenomation amongst... 

Snake venoms are complex mixtures of several different components or fractions that can vary considerably within Crotalinae members. A complete review of venom components is beyond the scope of this review. Depending on the content of the venom, multiple organ systems may be affected. Historically, Crotalinae venom was classified as neurotoxic, hemotoxic, cardiotoxic, or myotoxic, depending on the species of snake involved in the envenomation. This oversimplifies the complex nature of Crotalinae venom. Clinically, a patient may develop such multisystem disorders as platelet destruction, internal bleeding, hypotension, paresthesias, and rhabdomyolysis. 

Kitchens CS and Van Mierop LHS (1987) Envenomation by the Eastern coral snake (Micrurus fulvius fulvius) a study of 39 victims. Journal of the American Medical Association 258 1615-1618. 

Venomous snakes and venom have always been of interest to biologists. Historically, snake venoms were viewed as a valuable aid and were frequently used in early medical therapies. Ancient Egyptian and Chinese physicians utilized snake venoms as treatment for a variety of ailments and diseases. For over a century, snake venom has been used to develop antivenoms to treat snakebite envenomation. Currently, there are over 30 facilities worldwide that produce 120 different commercially available antivenoms. These antivenoms include both monovalent forms (effective for a specific species) and polyvalent forms (generally effective for several species that occur... 

A few extremely toxic and supertoxic chemicals are listed in Table 2, along with their environmental sources and toxicity targets. Some of these are toxins found in the venoms of poisonous snakes or in the tissues of certain species of animals. Dr. Findlay Russell, who has made enormous contributions to our understanding of the nature of animal toxins, their modes of biological action, and the procedures for treating people who have been envenomed or poisoned, estimates that there are about 1200 known species of poisonous or venomous marine animals, countless numbers of venomous arthropods (spiders), and about 375 species of dangerous snakes (out of a total of about 3500 species). 

F. Snakebite The most common dangerous snake in the USA is the rattlesnake. Although snakebites are common (several thousand per year in the USA), severe envenomation is infrequent. 

Effects Snake venom contains a large number of enzymes and tissue toxins. The most common effects of envenomation include local tissue necrosis, vascular damage, thrombosis, hemorrhage, and neural injury. 

The most common manifestation of serious envenomation is convulsions When a victim of a serious envenomation reaches the hospital, the most effective therapy is prompt administration of snake antivenin All of the above are correct... 

Of the 14 families of snakes, 5 are poisonous (Table 11-54). The annual incidence of snakebite in the United States is three to four bites per 100,000 population. Clinically significant morbidity occurs in less than 60%, and only a few deaths are reported each year. Rattlesnake bite is the most common snake envenomation in the United States, and the victim is often a young, intoxicated male who was teasing or trying to capture the snake. Snakes strike accurately to about one-third their body length, with a maximum striking distance of a few feet. 

Colubridae Lampropeltis Heterodon Coluber Dispholidus King snake Hognose Racer Boomsiang Human envenomation difficult because of small mouth and small fixed fangs in the rear of mouth. Larger African species may cause severe systemic coagulopathy. 

B. Elapidae. Coral snake envenomation is rare because of the snake s small mouth and fangs. The snake must hold on and chew the extremity for several seconds or more to work its fangs into the skin. 

C. Colubridae. These small-mouthed rear-fanged snakes must also hang onto their victims and chew" the venom into the skin before significant envenomation can occur. 

A. Determine whether the bite was by an indigenous (wild) species or an exotic zoo animal or illegally imported pet. (The owner of an illegal pet snake may be reluctant to admit this for fear of fines or confiscation.) Envenomation occurring during the fall and winter months (October-March) when snakes usually hibernate is not likely to be caused by a wild species. 

B. If the snake is available, attempt to have it identified by a herpetologist. Cau-f/on Accidental envenomation may occur even after the snake is dead. 

For coral snake envenomation, consult a regional poison control center ([800] 222-1222) or an experienced medical toxicologist to determine the advisability of Micrurus fulvius antivenin (see p 410). In general, if there is evidence of coagulopathy or neurologic toxicity, administer antivenin. 

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