Power point presentation on snake venom

2. Introduction
• Venomous Animal is capable of producing a
poison in a highly developed gland or group of
cells and can deliver the toxin by biting or stinging
• Poisonous Animal contains tissues that are, in
whole or part, toxic and there is no mechanism to
deliver the poison. Poisoning occurs by ingestion
only. Thus, all venomous animals are poisonous
but the reverse is not always true.

3. Animal irritants includes:- snakes,
scorions, bees, wasps, cantharides, spider,
and others
• SNAKES
• Snakes belongs to class reptalia, order
squamata and suborder serpentes. In the
world, there are about 2500 species of snakes,
500 are poisonous to humans. In India, there
are about 250 species out of which about 50
species are poisonous.

4. n
Cobra

6. Snakes are classified as
-Poisonous and
-Nonpoisonous
- and Nonpoisonous
Classification of poisonous snakes based on
their family
1. Colubridae: African boomslang, twig snake
2. Elapidae: Cobra and Krait(commonly caleed
Elapids)
3. Hydrophidae: Sea snakes
4. Viperidae: Vipers
5. Alractaspididae: Mole vipers or adders

7. Classification on the basis of venom
1. Elapids:- Neurotoxic
2. vipers: Vasculotoxic
3. Sea snakes: Myotoxic
Common poisonous Snakes in India
1. Cobra: King/common cobra
2. Krait: common/banded
3. Viper: Pit/Russell's/ Saw-scaled
4. Sea Snakes: Banded sea snakes, amphibian
sea snalkes

8. Snake venom
It is the toxic saliva secreted by specialized salivary
glands
• Features
1. Physical: Clear, transparent, pale liquid when fresh. It
becomes yellowish, opaque, granular powder on drying
and remains active for many years.
2. Chemical: It is heterogeneous mixture of proteins in
the form of enzymes' peptides and polypeptides.
3. Enzymes: The constituents of different snakes venoms
are proteinases, hydrolases, transaminase,
hyalurodinases, transaminase, ribonucleases,
deoxyribonuclease etc.

9. 4. Types of venom and action
• Elapids: Neurotoxin- It blocks the
neuromuscular junction and decreases the
output of acetylcholine.
• Vipers: Hemolytic and hemotoxic causes
intravascular hemolysis and depression of
coagulation mechanism and leads to
hemorrhage and necrosis
• Sea snake: Myotoxic. It leads to muscle pain,
myoglobinuria and hyperkalemia.

10. 6. Mode of Ejection and Transmission
of Venom
. In poisonous snakes, the poison is transmitted
through the hollow teeth known as fangs, which
are the modified upper marginal teeth. These
fangs are connected to the poison gland (venom
gland) by means of a duct. The venom gland in
poisonous snake is a modified parotid salivary
gland, which secretes and stores the toxic saliva
called venom. When the snake bites, muscles
compress the venom gland and force the venom
to come out of the fangs.

11. 7. Absorption
• The snake venom on ingestion is non-
poisonous since it can be digested. Poisoning
occurs due to direct snakebite, injection of
venom or absorption through abraded skin or
mucous membrane.

12. 6. Fatal dose, fatal period and amount
of venom injected
Snake Fatal dose Amount injected/bite
.Cobra 12mg 200-350 mg
.Krait 6mg 20-22 mg
.Russell v. 15 mg 150-200mg
.Saw-scaled
viper 6mg 25 mg
• Fatal Period: Few minutes to 1 week or more
depending on the type of Venom

13. Signs and Symptoms of poisonous
snake bite
1. Psychological trauma: Fright is the most common
symptom following snakebite due to enhanced
systemic absorption of venom. It develops almost
rapidly and may produce psychological shock and
cause sudden death. Fear may cause transient pallor,
sweating and vomiting.
2. Local manifestations: are present in the form of one
or more fangs(bite) marks seen as punctured wound,
edema…
3. Systemic manifestation: depends upon the type of
venom.

14. 4. Metabolic changes:-
ex. hyperkalemia and hypoxemia
5. Urine changes:- Haematuria, proteinuria,
hemoglobinuria, myoglobinuria and others
6. CSF:- Haemorrhage has been documented in
certain cases

15. Treatment
I. IN NON-POISONOUS SNAKE BITE
• a. Allay/lessen/calm the fear and anxiety
• b. Console/moral or emotional strength the
patients that not all snakes are poisonous

16. II. IN POISONOUS SNAKE BITE
1. Field management:
a. To allay fear and anxiety;- Shock is the commonest
cause of mortality in snake bite
b. Washing the area of bite with soap and water/saline or
potassium permanganate/neutralizes the poison/
c. Avoiding incision and sucking/no benefit/
d. Pressure immobilization technique/avoids absorption
and circulation/ but not in the case of viper
*application of tourniquet or bandage

17. 2. Hospital Management
a. Specific therapy: Antivenom serum or Antivenin
-It neutralizes the circulating toxins only and not the
toxin fixed in the tissues
b. Supportive treatment
PM finding
-puncture marks
-blood is fluid with dark red colour
- signs of asphyxia present
- congested visceral organ
- evidence of haemorrhage

18. Medicolegal Aspects
1. Accidental: Snakebite is usually accidental
2. Suicidal: Rarely except Cleopatra
3. Homicidal: Rarely for giving punishment in
ancient period.
4. Cattle poisoning

19. Laboratory Diagnosis
I. Samples to be collected in case of Snake Bite:
A. The aqueous washing of bite area on a clear
cotton swab (control sample of cotton to be
preserved also).
B. Blood serum or blood of victim.
C. The visceral tissues may be sent for examination,
if necessary to confirm the presence of other
poison (viscera is not suitable for detection of
venom).

20. II. Analysis of snake venoms:
• The analysis of snake venom is somehow
different as routine chemical tests are not
applicable. The skin portion around the bite
area may be a source of venom for
examination of its constituents by special tests
viz. test for cholinesterase or thromboplastin
in venom, toxicity test, clot quality test,
precipitin test, gel-diffusion test and immuno-
assays.

21. A. Test for Cholinesterase and
Thromboplastin in and around bite
area:
• The aqueous washings from the bite area may
tested for the activity of cholinesterase (in
case of bite by colubrine snake) and also
thromboplastin (in case of bite by viper
snake).

22. B. Toxicity Test:
• This test is a physiological test for confirmation of
snakebite.
• Procedure:
 The aqueous washings of the bite area or the
serum of the victim is injected into fowls/Hen
with or without antivenin. The death of the fowl
after injection of serum without antivenin and
the survival of the fowl after injection with
antivenin after a few hours confirms the
snakebite.

23. C. Clot Quality Test for Snake Venom:
• A capillary tube filled with blood taken from a finger
prick of the victim is kept horizontal for 30 minutes at
room temperature. It is then raised vertically. Non-
clotted blood due to consumption of fibrinogen or
defibrination runs out of its own accord or can easily
be blown out. This test is very useful in the diagnosis of
viper bite compared to the test for coagulation viz. the
prothrombin time, which is markedly reduced in a
viper bite.
• N.B. Clot quality test should be carried out at the time
of prick without delay.

24. D. Precipitin Test for Snake Venom:
• The test depends upon the fact that when a
foreign protein is injected into an animal,
certain specific antibodies known as preciptin
are formed in that animal’s blood which have
the capacity to precipitate the specific foreign
protein. The specific foreign protein, which
causes the production of the preciptin is
known as preciptinogen or antigen.

25. Other Tests
• Gel Diffusion Test:
• Immuno – Assays:

26. Reference
1. Forensic toxicology: A Comparative Approach
a book by Vipul Ambade
2.https://innovareacademics.in/journal/ijpps/Vo
l6Issue5/9275.pdf
3. Directorate of Forensic Science Toxicology
manual, MHA, Govt. of India
4.https://www.smithsonianmag.com/science/w
hats-difference-between-poisonous-and-
venomous-animals-180956186/

27. Thank you