There are about 3000 species of snakes, of which only 250-300 are poisonous. Snakes commonly found in our country are king cobra, common cobra, common krait, common striped krait, pit viper and Russell’s viper. Most of the snakes are harmless. Remember, all snake bites are not fatal. Generally people die from fear and not the venom. Most snakes bite only if provoked. Even the bite of a poisonous snake is not always dangerous, because when the snake bites in defense, little or no venom is injected.
The snake must be identified because no anti-venom is necessary if it is nonpoisonous. If it is poisonous, its type must be identified so that specific anti-venom can be administered. If the snake cannot be found or cannot be identified, it should be treated as poisonous, and general anti-venom should be given. The differences between poisonous and non-poisonous snaces are as shown below.
Poisonous and Nonpoisonous snakes
Variable – Poisonous – Nonpoisonous
Belly scales – Large, cover entire breadth of the belly. – Small or moderately large, but not covering entire breadth of the belly.
Head scales – Small.In case of vipers large and with : • Conspicuous pit between eye and nostril in pit viper.• Third labial scale touches the eye and nasal shields in cobra, king cobra, and coral. Central row of scales on back enlarged, the undersurface of mouth with only four infralabials, the fourth being the largest in krait. – Large.
Fangs – Long and grooved or canalized. – Short and solid.
Tail – Compressed.- Not markedly compressed.
Bite – Two fang marks with or without small marks of outer teeth. – A number of small teeth marks in a row.
The main characteristics of common poisonous snakes found in India are given below.
Cobra (naag or kala samp)
1.5to 2 meters long, black in colour, head of the same width as the trunk, neck has a hood with a spectacle mark, 2 or 3 series of very dark or black belly scales under the neck, and divided tail shields.
King cobra (raj naag or raj samp)
2.5 to 4 meters long, yellow, green, brown or black in colour, white or yellow cross bars on the body, hood without a spectacle mark, tail scales entire proximally and divided distally.
Common krait (manyar, chitti, or kawriya)
1-1.25 meters long, glistening black in colour, single or double white arches across the back, a short distance from the head, creamy white belly, head covered with large shields, tail scales.
Banded krait
2 meters long, alternate black and yellow bands across the back, and other features as of a common krait.
Common green pit viper (bamboo snake or hara phisi)
30-100 cms long, vivid green in colour, body flat and broad, head triangular with a pit between the eye and nostrils, yellowish white line on flanks, tail long with divided scales.
Russell’s viper (ghonus, daboia or khadchitro)
1.55 meters long, brown or buff in colour, three series of black diamond-shaped spots on the back, tail with divided shields, flat triangular head with a distinct V mark, belly white with broad plates.
Saw scaled viper (phoorsa, echis or afai)
50-75 cms long, brown, brownish-gray or greenish in colour, triangular head with a white arrow mark, wavy line on each flank, diamond shaped area between the upper curves of the two wavy lines, small head scales, serrated body scales, broad belly plates, tail shields entire.
How is a snake bite diagnosed ?
1. There is a history of snake bite.
2. There are 2 fang marks, a finger’s breadth apart.
3. Intense pain is experienced by the victim at the site of the bite of a viper. That area is swollen and blackened. Bleeding might be seen from different places. The patient vomits. Collapse and coma follow.
4. Fifteen minutes to two hours after the bite of a cobra or similar snakes neurotoxic effects are seen e.g. giddiness, lethargy, muscular weakness and spreading paralysis. Breathing becomes slow and labored. After a couple of hours, respiration ceases with or without convulsions, and the heart stops.
5. A bite from a sea snake is felt as a sharp initial prick that subsequently becomes painless. After 1-2 hours, generalized muscular pain and stiffness develop, starting in the neck, shoulders and hips. Urine becomes brown in colour. Respiratory failure may occur.
First-aid
1. Place the person on a flat surface comfortably.
2. Reassure him that all snakes are not poisonous, and the condition is curable.
3. Tie a tourniquet between heart and the bitten area to avoid absorption of the poison into the venous blood. Loosen it for a few seconds every ten minutes.
4. Immobilize the affected limb.
5. Make a 2.5 cm long cut over the bitten area and squeeze out blood mixed liquid from the wound.
6. Wash the wound gently with normal saline.
7. Apply ice packs on the wound if the area is on a limb.
8. Treat shock.
9. Shift the patient to hospital immediately, along with the killed snake, if available for identification.