Splint Black

Splint Black

Snakes And Their Living Nature

Snakes are remarkable animals, successful on land, in the sea, in forests, in grasslands, in lakes, and in deserts. Despite their sinister reputation, snakes are almost always more scared of you than you are of them. Few snakes, with the occasional exception of king cobras (Ophiophagus hannah) or black mambas (Dendroaspis polylepis), act aggressively toward a human without provocation.

Snakes have no limbs, yet all are meat eaters. They catch prey that includes insects, birds, small mammals, and other reptiles, sometimes including other snakes. Only about 400 of 3000 snake species worldwide inject venom (a poison).

Many snakes catch their prey by constriction. In constriction, a snake suffocates its prey by tightening its hold around the chest, preventing breathing or causing direct cardiac arrest. Snakes do not kill by crushing prey. Some snakes grab prey with their teeth and then swallow it whole.

Snakes are cold-blooded. Thus, they are unable to increase their body temperature and stay active when it is cold outside. They are most active at 25-32C (77-90F).

Snakes that inject venom use modified salivary glands. Venom is a modified form of saliva and probably evolved to aid in chemical digestion. Varying degrees of toxicity also make it useful in killing prey. During envenomation (the bite that injects venom or poison), the venom passes from the venom gland through a duct into the snake's fangs, and finally into its prey. Snake venom is a combination of numerous substances with varying effects.

In simple terms, these proteins can be divided into 4 categories. Cytotoxins cause local tissue damage, hemotoxins cause internal bleeding, neurotoxins affect the nervous system, and cardiotoxins act directly on the heart.

It has been estimated that 5 million snakebites occur worldwide each year, causing about 125,000 deaths. Snakebites are more common in tropical regions and in areas that are primarily agricultural. In these areas, large numbers of people coexist with numerous snakes. Five to ten deaths occur per year from snakebite in the United States.

People provoke bites by handling or even attacking snakes in a significant number of cases in the United States. Of the estimated 45,000 snakebites per year in the United States, about 8000 are by venomous snakes.

Two major families of snakes account for most venomous snakes dangerous to humans. The elapid family includes the cobras (Naja and other genera) of Asia and Africa; the mambas (Dendroaspis) of Africa; the kraits (Bungarus) of Asia; the coral snakes (Micrurus) of the Americas; and the Australian elapids, which include the coastal taipan (Oxyuranus scutellatus), tiger snakes (Notechis), king brown snake (Pseudechis australis), and death adders (Acanthophis). Highly venomous sea snakes are closely related to the Australian elapids.

The viper family includes the rattlesnakes (Crotalus) (Western diamondback rattlesnake and timber rattlesnake), moccasins (Agkistrodon), and lance-headed vipers (Bothrops) of the Americas; the saw-scaled vipers (Echis) of Asia and Africa; the Russell's viper (Daboia russellii) of Asia; and the puff adder (Bitis arietans) and Gaboon viper (Bitis gabonica) of Africa.

Most species of the most widely distributed and diverse snake family, the Colubrids, lack venom that is dangerous to humans. Some species, however, including the boomslang (Dispholidus typus), twig snakes (Thelotornis), the Japanese garter snake (Rhabdophis tigrinus), and brown tree snake (Boiga irregularis), can be dangerous. Other members of this family, including American garter snakes, kingsnakes, rat snakes, and racers, are harmless to humans.

Bites by venomous snakes result in a wide range of effects, from simple puncture wounds to life-threatening illness and death. The findings following a venomous snakebite can be misleading. A victim can have no initial significant symptoms, and then suddenly develop breathing difficulty and go into shock.

Signs and symptoms of snake poisoning can be broken into a few major categories. Bites by vipers and some cobras (Naja and other genera) are painful and tender. They can be severely swollen and can bleed and blister. Some cobra venoms can also kill the tissue around the site of the bite.

Bites by vipers and some Australian elapids can cause bleeding of internal organs such as the brain or bowels. A victim may bleed from the bite site or bleed spontaneously from the mouth or old wounds. Unchecked bleeding can cause shock or even death.

Venom from elapids and sea snakes can affect the nervous system directly. Cobra (Naja and other genera) and mamba (Dendroaspis) venom can act particularly quickly by stopping the breathing muscles, resulting in death without treatment. Initially, victims may have vision problems, speaking and breathing trouble, and numbness.

Venom from Russell's vipers (Daboia russellii), sea snakes, and some Australian elapids can directly cause muscle death in multiple areas of the body. The debris from dead muscle cells can clog the kidneys, which try to filter out the proteins. This can lead to kidney failure.

Spitting cobras and ringhals (cobralike snakes from Africa) can actually eject their venom quite accurately into the eyes of their victims, resulting in direct eye pain and damage.

Any snakebite victim should go to a hospital emergency department unless the snake is positively identified as nonvenomous. Remember, misidentification of the snake species could be a fatal error.

Bites by nonvenomous species require good wound care. Victims should receive a tetanus booster if they have not had one within the last 5 years.

Diagnosis of snakebite is made based on the history of the event. Identification or description of the snake would be helpful because not all snakes are venomous, and because different kinds of antivenom exist for different species of snakes. In Australia, the doctor may use a kit to determine the specific type of snake. The doctor also looks for evidence of fang marks or local trauma in the area of the bite. Pain and swelling accompany many snakebites.

The doctor treats breathing problems, shock, and/or immediately life-threatening injuries even before a full workup is complete. The wound needs to be examined and cleaned. The doctor will likely send blood and urine samples to the laboratory to look for evidence of bleeding, problems in the blood clotting system, kidney problems, or muscle death. These problems may not be initially apparent, but can have dire consequences if missed.

The victim is monitored to look for worsening symptoms at the wound site, or worsening systemic symptoms in the breathing or cardiovascular systems. A rare complication in very swollen limbs is compartment syndrome. Limbs are divided into compartments of muscles, blood vessels, and nerves.

Severe swelling can cut off the blood circulation to a compartment. When the circulation is cut off, the victim usually has severe pain and numbness. Later, the limb may get white and cold. If not treated in time, the limb may need to be amputated.

Moreover, remove constricting items on the victim, such as rings or other jewelry, which could cut off blood flow if the bite area swells. If you are in a remote area in which transport to an emergency medical facility will be prolonged, you should apply a splint to the affected limb.

If you do apply a splint, remember to make sure the wound does not swell enough to make your splint a tourniquet, cutting off the blood flow. Check to make sure toes and fingers are still pink and warm, that the limb is not going numb, and that pain is not getting worse.

If you have been bitten by a dangerous elapid and have no major local wound effects, you may apply a pressure immobilizer. This technique is mainly used for Australian elapids or sea snakes. Wrap a bandage at the bite site and up the extremity with a pressure at which you would wrap a sprained ankle.

Then immobilize the extremity with a splint, with the same precautions concerning limiting blood flow. This technique may help prevent life-threatening systemic effects of venom, but may also worsen local damage at the wound site if significant symptoms are present there.

While applying mechanical suction (such as with a Sawyer Extractor) has been recommended by many authorities in the past, it is highly unlikely that it will remove any significant amount of venom, and it is possible that suction could actually increase local tissue damage.