Animal poisons have evolved over millions of years and Snake Venoms are not an exception, yet all snakes are not Venomous. Some snakes are considered non-venomous yet every snakebite should be treated as equally harmful because even a non-venomous snake can produce harmful inflammations, allergies, swelling, etc. to its prey.
Snakes use their venom for two main purposes. Firstly, to kill its prey before eating it and secondly, for their defense mechanism from a predator. That’s how many people get attacked by snakes throughout the year. Snakebite was recently recognized as a tropical disease that has been neglected and affects 2.7 million people per year by WHO.
There are about 3500 snake species in the world and only 250 of them are venomous. Among these only 52 poisonous snakes are found in India. Common dangerous snakes found in India are King Cobra, Common Cobra, Common Krait, Russel’s Viper, Saw-scaled Viper.
Venom is the saliva of the snake. Snake venoms of different species vary in toxicity, composition, and antigenic structure which are a mixture of toxalbumins and enzymes, where, enzymatic components produce local and systemic effects and non-enzymatic components provide lethality.
Poisonous Snakes may be divided into 5 families i.e., Viperidae & Crotalidae, Elapidae, Hydrophidae or sea snakes, Colubridae, and Atractaspididae.
Types of Snake Venom
Snake venoms are of three types:-
- Hemotoxic Venom
- Cytotoxic Venom
- Neurotoxic Venom
Hemotoxins are the poisons of blood that directly affect Red Blood cells by damaging them and also interrupting in the Blood coagulation process. After being bitten by the snake the immediate response would be a pain.
The venom inside the body starts working by killing red blood cells which will lead to tissue death and since the blood clotting is affected, serious internal bleeding will occur which may result in death. Sometimes, Organ failure may also result in death.
When dead RBC’s are accumulated, they may also disrupt kidney functioning or may also lead to kidney failure. In some cases, hemotoxins also clump platelets with blood cells which may disrupt blood circulation in the body, causing heart failure.
Some of the examples of these snakes are Rattlesnakes, Copperheads, Cottonmouths.
Cytotoxins are toxic substances that spoil body cells. Cytotoxins lead to the loss of life of most or all of the cells in a tissue or organ, a condition known as necrosis. Some tissue may additionally trip liquefactive necrosis in which the tissue is partly or absolutely liquefied. Cytotoxins assist to partly digest the prey earlier than it is even eaten. Cytotoxins are typically particular to the type of cell they impact.
Cardiotoxins are cytotoxins that damage heart cells. Myotoxins goal and dissolve muscle cells. Nephrotoxins wreck kidney cells. Many venomous snake species have an aggregate of cytotoxins and some may additionally also produce neurotoxins or hemotoxins.
Cytotoxins smash cells by means of unfavorable the cell membrane and inducing cell lysis. They may additionally also cause cells to endure programmed apoptosis. Most of the observable tissue damage brought by the means of cytotoxins occurs at the site of the bite.
Some of the examples of Cytotoxic venomous snakes are Puff Adders, Gaboon Vipers, and Mozambique Spitting Cobras.
Neurotoxins affect the Nervous system and are severely toxic. Snakebites from neurotoxic snakes work by disrupting nerve functions i.e., disrupting chemical signals sent between neurons. Neurotoxic venom can be either presynaptic or postsynaptic. Either both types can be found in snake venom or only one may be present.
Neurotoxins bind to the nerve receptors reducing the transmitted signals or blocking the reception sites. Neurotoxins cause muscle paralysis and death will occur due to the non-functioning nerves or respiratory failure. Brain damage doesn’t occur due to neurotoxin as the molecules of toxins are not small enough to pass the blood-brain barrier.
Usually, the Snake family ELAPIDAE produces Neurotoxins. Some of the examples of snake Neurotoxins include:-
- Calciseptine-> Produced by Black Mamba
- Cobrotoxin-> Produced by Cobras
- Calcicludine-> Produced by Eastern Green Mamba
- Fasciculin-I-> Produced by Eastern Green Mamba
- Calliotoxin-> Produced by Blue Coral Snakes