Types of Snake Venom

Out of the 2950 known snake species in the world (2007 figures), only 450 are venomous, making it just about 15.25 percent from their entire population. Out of the 7000 Americans that are annually reported with snakebites, less than 15 die of the toxic poison. Yet, people go after snakes, trying to kill them at sight, as just the mere sight of one sends everyone into a panicked frenzy. Why? Can you guess by looking at a man, if he's a terrorist? Can you guess from the appearance of someone, if he/she is a psychopathic murderer? And yet both of these are more of a threat to America, and indeed the world, than snakes ever were. Most snakes are not venomous and even from those that are, only about 250 are capable of killing humans.

Snakes are dangerous because of their venom. My crash course in organic chemistry hence starts with venom. Venom is essentially highly modified saliva that is made up of 90 percent proteins and about 20 percent enzymes. Most of these enzymes are harmless to humans and are generally not dangerous when ingested. Hence, technically, venom is not really poison. These scientists really do come up with amazing findings, no? Anyway, there are about 20 toxic enzymes known to man and unique mixtures of these zootoxins and proteins, form the lethal weapons of snakes. The venom contains phosphodiesterases (attacks the cardiac system), cholinesterase (loss of muscle control), hyaluronidase (increased tissue permeability), ATPases (disrupt energy fuel use) and various amino acid oxidates and proteases. The venom is stored in a large sac-like structure, known as the aveoli and it is injected through a set of tubular fangs.

Snake venom can be broadly categorized into many types, but I will be explaining the most fascinating four:

Hemotoxic Venoms
These venoms attack the cardiovascular system, circulatory system and muscle tissues, thus directly leading to heart failures. The 'crotalus adamanteus', notoriously known as the western diamondback rattlesnake, uses this deadly venom to make its prey more pliable. I meant like kill it, duh! This venom causes the poisoning of blood and affects the blood clotting mechanism to such a grave extent, that the victim can die of internal bleeding. Usually, no pain nor any other symptoms can be observed for almost 1 - 3 hours (sometimes even 8). This makes it deadlier, as the victim is usually beyond medical help, by the time the cause is even ascertained. The effects of this venom can be seen as lethargy, headaches, nausea, vomiting, etc. The most scary observations of the outcome of a snakebite of this kind are bruising or blood spots beneath the victim's skin. In extremely bad cases, blood is known to ooze out from all possible bodily openings. It is these venoms that usually cause excessive (and hideous) scarring, gangrene and permanent or temporary loss of motor skills. Worst cases can even result in the amputation of the affected limb.

Neurotoxic Venoms
These venoms go after the central nervous system and brain. They often result in respiratory paralysis and heart failures. Their effect can range between mild seizures to death. Cobras, mambas, sea snakes, kraits and coral snakes are known to possess this venom. The king cobras (ophiophagus hannah) are the most infamous carriers of this venom. Neurotoxic venom is essentially nerve destroying. Hence, one can see speech and swallowing difficulties, drooling, difficulty in breathing, respiratory arrests, convulsions and sometimes even prolonged unconsciousness in the victims. The milder symptoms are dizziness, tunnel vision, blurred vision and increased sweating. This venom causes a very fast degeneration of the synaptic nerves and this is the reason for the blockage of nerve impulses sent to and from the brain to the muscles.

Cytotoxic Venoms
This is a milder venom that generally causes only localized symptoms at the location of the bite. This is a cell destroying venom that destroys everything in its path - blood vessels, cells and tissues. The symptoms of the invasion of this venom are generally seen around 10 - 15 minutes after the snake encounter (I meant bite, not the spotting). The results are generally localized pain accompanied by severe swelling and bleeding. One can easily spot the formation of red blisters near the bite area. This venom causes blue/black spotting due to limited blood circulation. The body often revolts against the invasion of this venom by causing nausea and vomiting. If this venom is not treated within four hours, it generally needs an amputation. Puff adders (bitis arietans) are the snakes to be avoided if one is pain phobic.

Myotoxic Venoms
This venom is found in the 'bothrops moojeni' snakes, commonly known as the Brazilian lancehead snakes. This venom is known to cause muscular necrosis. Its symptoms are a thickened-tongue sensation, dry throat, thirst, muscular spasms and convulsions. It also causes the stiffness of the jaw, neck, trunk and limbs along with severe pain in movement. The victims often start with drooping eyelids and then turn to more austere results like loss of breath and blackish brown urine discharge. Myotoxic venom contains peptides that destroy the muscle fiber proteins and result in myonecrosis (muscle destruction). In the very later stages (when treatment is delayed) of the spread of this venom, the muscle proteins enter the blood stream. The kidney overworks in trying to filter out this junk and often gives up trying. This kidney failure is the reason for the dark coloration of urine.

Snake venom is not dangerous if medical treatment is speedily provided. Where it is not possible to get medical aid quickly, it is always advisable to be aware of the first aid measures. Some far out places in South Africa, that do not even speak English, actually ensure that first aid in case of snakebites, is a subject tackled in schools. They know that a snake will not bite when the hospital is near. They also know that there are many killer snakes in South Africa. These animal loving people have devised a way to live with the snakes, by simply being aware and taking care. They try to live in harmony, where no man kills the snake and the snakes return the favor. No wonder then, that Africa is a part of the few remaining wildlife havens.