This document provides information on poisonous snakes found in India, their identifying characteristics, and the symptoms and treatment of snake bites. It discusses the most common poisonous snakes such as cobras, kraits, and vipers. It describes the local and systemic effects of bites from elapid (neurotoxic) snakes, viper (vasculotoxic) snakes, and sea snakes (myotoxic venom). The treatment section covers first aid measures, use of antivenom serum, and managing symptoms caused by the different venom types through means such as atropine, neostigmine, heparin, and fibrinogen.

1. (Irritant organic animal poison)

2.  In the world, there are about 2500 species of snakes. In
India, there are about 250 species, out of which about
50 species are poisonous.
 The common poisonous snakes in India are Cobra (naja
naja), King Cobra (ophiophagus hannah), Krait
(bungarus caeruleus), Banded krait (Bungarus
fasciatus), Russell's viper (daboia ruselli), Saw-scaled
viper (echis carinatae) and Sea-snakes, most common
being krait.
 Snakes are found all over the world except in
Greenland, Ireland, Iceland, Jamaica and New Zealand.
There are no vipers in America.
 Snakes have an elongated body and a short tail, that is
the part behind vent i.e. the opening for intestine and
genitourinary system.

3.  There are no limbs. Eyelids being fused appear to be
absent. The body is covered by scales and the head has 2
eyes, 2 nostrils, no external ear and a distensible mouth.
 Tongue is forked and helps as a sense
organ. Teeth are thin, directed
backwards and the upper marginal
teeth are long and canalised and are
known as fangs.
 Fangs can be replaced in 3-6 weeks when
broken. The fangs in poisonous snakes are
connected by a duct to the venom glands
(racemose glands) i.e. modified parotid
salivary glands.
 Colubrine are oviparous, while vipers are viviparous.
 For medicolegal purposes, snakes are classified as :
1) Poisonous 2) Non poisonous

4. Poisonous Non poisonous
1) Body scales i.e. on anterior side are
large and cover the whole width.
1) They are small or moderate.
2)Head scales are small e.g. in Vipers.
However there are few exceptions -
a) In pit viper, there is a greenish pit
between eye and nostril.
b) In Cobra and King-cobra, the third
labial is large and touches the eye.
c) In krait, the central row of scales on
the back is large, and the 4th infralabial
is very large.
2) The head scales are large
3) Fangs are present and they are
canalised (in vipers) or grooved in
colubrine)
3) Usually, fangs are absent. If present,
they are short and solid.
4) Tail is compressed 4) Not so.
5) Generally noctural 5) Not so.
6) Bite - mark shows 2 fang marks and
there may be present the marks due to
other small teeth (in colubrine).
6) No fang marks.
7 ) Saliva toxic 7) Non toxic

7. 1) Colubridae :
 Elapidae :- Cobra and krait; pupil is round .
 Hydrophiidae :- Sea Snakes, pupil is round.
2) Viperidae - includes vipers, pupil is vertical
 On the basis of poison, the snakes are Classified as :
1) Elapids - Neurotoxic - Fangs are 4-6 mm.
2) Vipers - Vasculotoxic - Fangs are 12-15 mm, mobile.
3) Sea snakes - Myotoxic - Fangs are 2-4 mm.

9. 1) Cobra (Mar & Guj- Nag): It is usually black, 5-6 feet,
has a hood on dorsal side on which there is a single or
double spectacle mark or an oval spot surrounded by
half circle. On ventral side are 2 black spots. Head
scales are large & third supralabial is big. The colour is
brown or dark. It prefers populated areas.

10. 2) King - Cobra (Mar- Nagraj) : Is 6-18 feet, there is no
mark on hood, prefers forests.
The colour may be yellow, green,
brown or black and has yellowish
or white cross bands on the body.

11. 3) Common Krait (Mar- Maniyar, Guj- Kalo taro):
 Is usually steel-black, 3-5 feet. It prefers area in or near
the houses. The head shields are large, there are four
infralabial shields and scales in central row on back are
large and hexagonal. There are single or double white
arches across the back. Nocturnal in habit.

12. 4) Banded krait (Mar- Pattere Maniyar) Is 5-7 feet and has
2" broad alternate black and yellow bands on the body
(rarely dark brown and light brown), in addition to
features as in common krait.
Head :
Black mark
Triangular
Back
Rounded Tail tip

13. 5) Pit-Viper : Is 1-3 feet and has a heat sensing green pit
between each eye and nostril. Usually found in hills.

14. 6) Russels Viper : (Mar- Ghonas, daboia, Guj- Chitalo,
Khadchitalo) : Is 4-5 ft. long. Head is flat, triangular
and has white, V shaped mark, pointing forwards.
Body wide and has 3 rows of diamond shaped marks.
It produces loud hissing sound when about to attack.

15. 7) Saw-scaled viper : (Mar- Fursa : Guj- Tarachha ) Is 1-1.5
ft. usually brown, head is triangular and having a wide
mark which resembles an arrow or of each scale are like
a saw - hence the name saw scaled viper. These rough
scales produce rustling sound when snake moves.

16. 8) Sea Snakes : Have a snout and tail is fin like. They are
black, greenish black or bluish black with or without
bands. 20 types are seen in Indian waters, all of them
being poisonous.

17.  Snake venom (toxalbumin) is heterogeneous mixture of
proteins produced and stored in the specialised salivary
glands.
 The freshly secreted venom is transparent, pale liquid
and on drying it becomes yellowish, opaque, granular
powder which remains active for many years.
 The proteins in the venom are in the form of enzymes,
peptides and polypeptides.
 The enzymes are
 Proteinases, - Ribonuclease,
 Hydrolases, - Deoxyribonuclease
 Transaminase, - Phosphomonoesterase,
 Hyaluronidase, - Phosphodiesterases
 Phospholipase A, B, C & D, - 5-nucleotidase,

19.  ATPase, - Coagulases
 Alkaline phosphatase, - Agglutinins,
 Acid phosphatase, - Fibrinolysin
 Cholinesterases - Haemolysin etc.
 In elapids there are neurotoxins, which are
polypeptides. They block the neuromuscular junction
and thus decrease the output of acetyl choline.
The marked toxicity is on CNS, respiration and heart.
 The viperine venom is mainly haemolytic,
hemorrhagic and necrotic.
It causes intravascular haemolysis and depression of
coagulation mechanism.
 The sea snake venom is myotoxic. It leads to muscle
pain, myoglobinuria and hyperkalemia.

20.  Proteolytic enzymes : Cause digestion and
destruction of tissue proteins.
 Hyaluronidase: Helps spread of venom.
 Phospholipase: Causes Hemorrhaging : Causes
spontaneous bleeding.
 Haemolysin Causes lysis of RBC
 Leukocyten : Causes lysis of WBC
 Cytolysin : Causes damage of internal viscera.
 Rhabdomyolysis : Causes necrosis of muscles.
 Proteases Causes dissolution of blood vessels.
 Fibrinolysin Breaks down fibrin and causes lysis of
clot.

21.  The snake venom on ingestion is non poisonous since it
can be digested.
 Poisoning occurs due to snake bite, injection of venom
or absorption through abraded skin or mucous
membrane.
 The manifestations depend upon age, size and health
of snake and site of bite. Sometimes sudden death may
occur due to fright.
 The snake venom can be detected by
radioimmunoassay (RIA) or enzyme immuno assay
(EIA).

22. 1) ELAPIDS
A) LOCAL MANIFESTATIONS:
 They are mild in the form of burning and triple
response (i.e. redness, swelling, and inflammation) at
the site of bite.
B) SYSTEMIC : Neurotoxic, vomiting, dizziness, lethargy,
salivation, extraocular muscle paralysis, ptosis,
difficulty in speaking and swallowing, muscle
weakness and pain, staggering, spreading paralysis
(ascending from lower limbs), convulsions and death.
 (No convulsions in Krait)

23. II) VIPERS :
A) LOCAL MANIFESTATIONS :
 Intense pain, swelling, irritation, cellulitis, cyanosis,
oozing of blood serum and formation of blisters
containing sero-sanguineous or rarely serous fluid.
 After 1 week - necrosis develops at the site.
 Absence of oozing of blood serum indicates that
venom has not been injected in wound (failure of
clotting is due to low levels of fibrinogen)
B) SYSTEMIC : Vasculotoxic, vomiting, unconsciousness,
intravascular hemolysis leading to hemoglobinuria,
Petechial haemorrhages on various mucous
membranes and organs, bleeding from body orifices
and hypotension.

24. III) SEA SNAKES
A) LOCAL MANIFESTATIONS : The prick is initially
painful but is soon painless.
B) SYSTEMIC : Myotoxic, vomiting, muscular pain,
muscle stiffness, collapse, myoglobinuria,
hyperkalemia and increased serum transaminase
levels.
 LABORATORY FINDINGS :
1) RIA/EIA/ELISA To detect antigen
2) Blood Leukocytosis, thrombocyto-paenia, haemolysis,
prolonged clotting and prothrombin time,
hypofibrinogenemia
3) Metabolic - Acidosis, hyperkalemia
4) Urine :- Presence of Hb, albumin, blood & azotemia.

25.  FATAL DOSE:
 FATAL PERIOD:
- In Colubrine -: 20 min. to 6 hrs.
- In Viperine -: 2 to 4 days.
Snake Fatal Dose
Amount Injected
per bite
1) Cobra 12 mg of dried
venom
200-350 mg.
2) Krait 6 mg. -" 20-22 mg
3) Russels viper 15 mg. -" 150-200 mg
4) Saw scaled viper 8 mg. -" 25 mg

26.  The treatment includes :
1) To allay fear and anxiety.
2) Prevention of spread of venom.
3) Use of antivenom serum.
4) Treatment of absorbed venom
5) Symptomatic and general treatment
1) ALLAYING FEAR AND ANXIETY :
 The commonest cause of mortality in snake bite is fear
and tension.
 Every patient should be reassured that all snakes are
not poisonous and that the poisonous snake bite can be
treated.

27. 2) PREVENTION OF SPREAD OF VENOM :
a) Clean the bite area with soap and water or saline.
b) Washing with KMnO4 solution neutralises the poison.
c) Give a 0.5 cm deep incision through the fang marks and
suck the area with mouth, breast pump or suction
machine (In case of any ulcer in the mouth or upper
GIT, sucking by mouth should not be done).
d) Apply tourniquet proximal to the site of bite (if bite is
on extremity) preferably two tourniquets applied, out
of which one should be preferably on a single bone.
(The tourniquet should be released for 20-30 sec. every
20-30min. to avoid gangrene and it should be tight
enough to occlude lymphatics but not veins).
e) Immobilise the part since it prevents spread of venom
and relieves pain.

28. f) Local heparin infiltration in vipers and carbolic soap
solution in elapids is useful.
g) According to some, local emetine or gold chloride
injection, at the site of bite helps to prevent the spread.
3) USE OF ANTIVENOM SERUM : (Antivenom therapy)
To counteract the toxic effects of snake venom, anti
snake venom serum is used.
 It should be started before releasing the tourniquet. (It
is prepared by injecting the snake venom into horse
and collecting the antibodies).
 The anti-snake venom serum may be monovalent i.e.
effective against a specific snake (not available in India)
or polyvalent which is effective against Cobra, Krait,
Russell's viper and Saw-scaled viper.

29.  This serum is lyophilised i.e. is freeze dried and is
available as granular powder. It is reconstituted by 10
ml of distilled water (Be sure that the solution is clear).
 The serum remains potent for about 10 years.
 Since it is a serum, if time and condition of the patient
permits then sensitivity test should be done injecting
0.1 ml intradermal.
 In a person who is not sensitive, 20 ml of the serum is
injected, I.V. 5 ml/min and it can be repeated if
required.
 (As per some books the serum should be given 20 ml
I.V. 20 ml IM and 20 ml at the site of bite). Local
injection is useful in vipers to avoid local gangrene.
 If a person is sensitive to the serum, he is desensitized
by injecting multiple small doses, under cover of
adrenaline, antihistaminics and corticosteroids.

30. 4) TREATMENT OF ABSORBED VENOM :
a) In elapids :
- Alternate 0.6 mg atropine and 0.5 mg neostigmine.
- In paralytic cases SC adrenaline and IM calcium
chloride
b) In Vipers :
1) 30,000 – 40,000 units heparin.
2) 300 - 600 gms fibrinogen.
3) It has been found that a very high voltage i.e. 20,000 –
30,000 volt and very low amperage i.e. 1-2 milli amp.
current applied at the site of bite is useful.
5) SYMPTOMATIC AND GENERAL TREATMENT :
Use of tetanus toxoid, antibiotics, antihistaminics,
analgesics, barbiturates, steroids, blood transfusion,
artificial respiration and hemodialysis.
- IgG is said to improve coagulopathy

31.  - Snake bite is usually accidental. Annually about 2
lakh people are bitten by snakes and about 30,000 die.
 - Suicides are not common. Cleopatra (queen of Egypt)
committed suicide by getting herself bitten by a viper.
 - Sometimes relatives attribute a suicidal or homicidal
death to be due to snake bite.
 - Sometimes snake venom is used as cattle poison
(Venomised banana or rug thrust into rectum).
 - Snake venom can cross placenta and hence can poison
foetus.
 - Polyvalent antivenom is prepared at -
- Haffkine Institute, Mumbai.
- Central Research Institute, Kasauli, HP.
- King's Institute, Chennai.
- Serum Institute, Pune.