Oct 20, 2016
Worldwide, only about 15 % of the more than 2000 species of snakes are considered dangerous to humans, of which 290 are present in India ranging from the 10 cm long worm snake to the 7 meter long python and King Cobra. The best part is that only 52 are venomous and restricted to specific geographical regions. Hence, the chances of a snake bite are highly specific to a few snakes adapted to a particular habitat. This makes identification based on fang markings more reliable.The composition of venom of a single snake species varies from place to place, season to season and between adults and their young. Individual snake venom may even change with its diet.
In this brief article we have highlighted, importantinformation regarding snake bites in India caused by the big four, namely Spectacled Cobra, Common Krait, Russell’s viper and Saw-Scaled Viper. Before reading any further it is desirable to understand the difference between Poison and venom. Poison must be inhaled, ingested, or delivered via touch, while venom is injected into a wound. Hence in our opinion, the term poisonous snake is incorrect. (We also stand to be corrected).
The annual number of cases of snake bite worldwide is about 5 million resulting in 15-200,000 deaths per year. India is estimated to have the highest snake bite mortality in the world.The World Health Organization (WHO) estimates, place the number of bites in India to be 83,000 per annum with approximately, 11,000 deaths.
Proper first aid is of paramount importance in the life of a snake bite victim, especially in the first hour, also known as the “golden hour”. The facts state that 80 % of the snake bites are by non-venomous snakes. On the other hand,it is very important to understand that 50 % of bites by venomous snakes are dry bites that result in no harm. This is because snakes have complete control over how much venom they inject anytime they bite. So one could get a “DRY BITE”, with no venom at all.
With respect to bites from venomous snakes, 70-80 % of the bites are attributed to Russell’s viper and saw - scaled Viper, which involve hemotoxin/ vasculotoxin. The spectacled Cobra and Common Krait together constitute 30 % of the bite and are neurotoxic in nature.
Statistics show that the snake bite between males and females is in the ratio of 2:1.Majority of the bites being on the lower extremities.It is also important to note that snakes inject the same doze of venom into children and adults. Children must therefore be given exactly the same doze of antivenom as adults.
In India the big four, namely the spectacled Cobra, Common Krait, Russell’s viper and Saw Scaled viper, together, are known to cause more than 90 % of the snake bite deaths. The venom of Krait and Russell’s viper is much more toxic than that of cobra.
Basically snake venom is classified into four types.
Neurotoxic. e.g. Cobra. The venom paralyses the respiratory centre.
Hemotoxic. e.g. Russell's viper. The venom typically affects the blood, resulting in necrosis (death of tissue) and anticoagulant (preventing the blood from clotting).
Myotoxic. e.g. Sea snakes. The venom results in muscle breakdown.
Cardio toxic e.g. S.Cobra. Affects the heart.
(Slide from https://commons.wikimedia.org/)
DIAGNOSIS OF SNAKE BITE
FANG MARKS: Classically, two puncture wounds separated by a distance varying from 8mm to 4cm, depending on the species involved. However a side swipe may produce only a single puncture, while multiple bites could result in numerous fang marks. The Effects of envenomation can be categorized into four distinct types namely,Neurotoxic (Krait &Cobra), Hemotoxic(Russell’s viper)Cardio toxic(Spectacled Cobra &others) andMyotoxic (Sea Snakes).Maximum, with Viper bite, least with Krait bite. Hence krait bite can sometimes go unnoticed.
ANTI-SNAKE VENOM (ASV)
ASV is the main stay of treatment. Antivenom is immunoglobulin purified from the plasma of a horse. Mule, donkey, or sheep that has been immunized with the venoms of one or more species of snake. In India, polyvalent ASV is effective against all the big four.
The following slides have been selected from the power point presentation by Josel Louies.
The website Indiansnakes.org is an ideal reference to learn all about Indian snakes and their conservation. The link below provides a power point presentation by Josel Louies who has provided Snake Bite- Facts, First Aid and prevention.
A NOTE TO READERS:
The Catholic Association of South Kanara (CASK) is a hundred year old organization, based at Mangalore. CASK has initiated a footwear project in rural schools at a place called Badiyar (50 kms from Mangalore).Badiyar records a significant number of snake bites, both venomous and nonvenomous, especially in school children as they walk to school barefoot through the forests. People, interested in knowing more about the project can kindly email at firstname.lastname@example.org
The snake photographs has been kindly provided byJoy Mascarenhas, Ujre. Joy is a herpetologist, a person with interest and expert knowledge on the natural history of reptiles.Joy S Mascarenhas can be contacted at +91 9743432626, Snakejoy1@gmail.com. Joy recently rescued and released the 150th King Cobra.
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