The venom of different snakes has its own characteristic effect. The bitten person may die or recover depending upon the amount injected and its virulence. There are two types snake venoms – Neurotoxic and Haemotoxic.
Neurotoxins are typical of elapsids (Cobra and Krait) and sea snakes. The cause of death by paralysis of respiratory muscles and asphyxiation. Haemotoxins are typical of vipers. They cause tissue destruction and widespread haemorrhage. The effects of venom or symptoms of snake bite in case of 3 most common poisonous snakes of India are as follows :
Cobra bite—Poison of Cobra is neurotoxin attacking nerve centres and causing paralysis of muscles especially those of respiratory muscles. Symptoms include piercing pain and burning sensation ending in numbness of bitten part which turn bluish. Person suffers from giddiness, weakness in legs, high pulse rate, speechlessness, drooping of saliva and eyelids, contraction of pupils, vomiting and laboured breathing. Death results within few hours due to failure of respiration (asphyxia) or heart failure.
Krait bite—Kraits are most dangerously poisonous snakes because their bite injects a very large quantity of poison. Symptoms are very similar to those of cobra bite, except that the victim complains of unbearable abdominal pain due to internal haemorrhage. Destruction of RBCs (haemolysis) and paralysis of trunk and limbs occur followed by death within 6 to 24 hours.
Viper bite—Venom of viper is mainly haemotoxic affecting the circulatory and nervous system more severely. Symptoms include local swelling and discolouration of bitten part with acute burning pain. A red fluid oozes out from wound due to massive tissue destruction (necrosis)
which frequently necessitates amputation. Pupils dilate, pulse rate increases profuse vomiting occurs and victim loses consciousness. Death may result due to paralysis of vaso-motor centres and exhaustion from profuse bleeding.