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IN THE NAME OF
THE MOST BENEFICENT THE MOST MERCIFUL
SNAKE BITE
Irfan Ahmed
SNAKE BITES
Reptiles–Snakes
Arthropods–Scorpions–Spiders–Ticks–Insects
ARTHROPODS
• At least 750,000 species
• Three times number of all other animal species combined
• Scorpions, spiders, ticks, Insects etc.
ARTHROPODS
SNAKES A world free of snakes• Nearly a quarter of us would go
hungry• Are important elements in the food
chain to control the rodent population- Which destroy all major crops
The bottom line is we need snakes to survive
•Snakes belong to the order of animals called reptiles•This group also include crocodiles, lizards, and turtles•Snakes maintain a fairly steady body temperature by their behavior•Raise their temperature by lying in the sun or lower it by crawling into the shade
SNAKES
•Snakes have a long, legless, flexible body that is covered with dry scales•Snake's eyes are covered by clear scales rather than movable eyelids; therefore, their eyes are always open
SNAKES
•They repeatedly flick out their narrow, forked tongue, using it to bring odors to a special sense organ in the mouth
SNAKES
SNAKES – EVOLUTION• Early snakes killed their prey using surprise attacks and by suffocating them to death
• Snakes evolved a venom as new weapon about 60 million years ago
•3000 species of snakes in the world•375 are venomous (10 to 15 %)
SNAKES
WORLD DISTRIBUTION OF SNAKES
• Occur practically all over the world, apart from places like Greenland, Iceland, and Antarctica
• Most snakes are found in tropical regions
SNAKES – HABITAT• Long grass• Shrubs & hedges• Holes & burrows• Shady places like
under pre-fabricated construction
• Garbage pits
SNAKES – COLD BLOODED
• Do not have the ability of generating adequate amounts of heat in order to keep their body temperature at a constant level
• Dependent on the heat from their surroundings and the sun to control the temperature of their body
• Most snake species are found in the humid and warm climes of tropical regions
SNAKES – SIZE • Anaconda can
grow up to 38 feet in length
• Brahminy blind snake is just 2 inches long, making it the smallest snake
SNAKES – SENSE OF HEARING
• No external ears• Probably deaf to
most sounds• Hear by sensing
vibrations with their belly scales and lower jaw
SNAKES – SENSE OF SMELL
• Snakes use their forked tongue to smell
• Tongue gathers airborne particles
SNAKES – COLOUR• Dull to brilliant with
striking patterns• Dull for camouflage• Brightly coloured are
usually poisonous• Use bright colours to
warn predators• Some non-poisonous
snakes mimic the patterns and bright colors of poisonous snakes to fool predators
SNAKES – METABOLISM• Slow rate of metabolism
• King Cobra can go for months without food
SNAKES – MOLTING• We shed small
quantities of old skin continuously
• Snakes shed their old skins in a continuous sheet (a process called ecdysis)
SNAKES – MOLTING• Interval between
sheds depends on age, growth rate, environmental factors
• Young shed more frequently
• Adult snakes shed less often
SNAKES – CRAWLING• The type of
movement used depends largely on the terrain
Concertina Serpentine Side – winding Rectilinear
SNAKES – VENOM• Venom is the
toxic saliva produced by the parotid salivary glands of the poisonous snakes
•Snake venom is highly modified saliva, and is produced by modified saliva glands•Proteinaceous nature of snake venom was established by Napoleon Bonaparte's brother, Lucien in 1843
SNAKES – VENOM
•Proteins constitute the major portion of venom's dry weight–90% or more•Snake venom is a cocktail of hundreds, sometimes thousands, of different proteins and enzymes•Many of these proteins are harmless but a percentage of them are toxins•The makeup of these toxins varies widely from species to species•This complexity accounts for the widely differing effects of snakebite
SNAKES – VENOM
SNAKES – VENOM• Composition
Fibrinolysins Proteolysins Neurotoxins Cholinestarses Haemolysins Thromboplastin Agglutinins Cardiotoxins Hyaluronidase
POISON GLANDS AND VENOM EXTRACTION
POISON GLANDS AND VENOM EXTRACTION
•Venoms are rich in hydrolithic enzymes, a complex mix of polypeptides, nucleases, peptidases, etc., which help digest the snake's prey•Some of them also enhance or contribute to the toxic effect of the venom
SNAKES – VENOM
•Hemotoxin (blood toxin) Hemotoxic venom attacks the circulatory system
and muscle tissue causing excessive scarring, gangrene, and sometimes leads to amputation of the affected area
This venom basically destroys tissue and blood cells
In addition to killing the prey, part of the function of a hemotoxic venom for some animals is to aid digestion
The venom breaks down protein in the region of the bite, making prey easier to digest.ex : Vipers
SNAKES – VENOM
SNAKES – VENOM• Vasculotoxic
poison Enzymatic
destruction of cell membranes and coagulation disorders
Result in Destruction of
endothelial cells of blood vessels
Lyses of RBCs Failure of blood
clotting
•Neurotoxin (nerve toxin) Neurotoxic venom attacks the
victim's central nervous system and usually result in heart failure and/or breathing difficulties or even total respiratory paralysis. eg: Cobras, Kraits, Coral Snakes
SNAKES – VENOM
SNAKES – VENOM• Neuro Toxin
Acts on motor nerve Similar manner to tubocurarine poison Compete with acetylcholine at
nicotinic receptors Render acetylcholine inactive Leading to muscular weakness
SNAKES – VENOM• Krait- Pre-synaptic action
Beta-bungarotoxin- Phospholipases A2 Inhibiting the release of acetylcholine from
the presynaptic membrane Presynaptic nerve terminals exhibited
signs of irreversible physical damage and are devoid of synaptic vesicles
Antivenoms & anticholinesterases have no effect
Paralysis lasts several weeks and frequently requires prolonged MV. Recovery is dependent upon regeneration of the terminal axon
SNAKES – VENOM• Krait- Pre-synaptic action
1) Inhibiting the release of acetylcholine from the presynaptic membrane
2) Presynaptic nerve terminals exhibited signs of irreversible physical damage and are devoid of synaptic vesicles
3) Antivenoms & anticholinesterases have no effect
SNAKES – VENOM• Myotoxic poison
Muscular pains Myoglobinuria Respiratory
failure due to muscular weakness
CLASSIFICATION OF SNAKES
Five families
Clo
bri
dae
Boid
ae
• V
ipers
Vip
eri
da
e
• Cobra
s
Ela
psid
ae
• Wate
r sn
ake
s
Hyd
rop
hiid
ae
CLOBRIDAE• Most numerous
snake family • Two third of all
snakes in the world• Majority are
non-poisonous• Examples
— Corn snakes— Rat snakes
• Largest (size) snakes in the world
• Non-poisonous (Use their strength to constrict and kill prey)
• Three largest snakes— African rock
python— Reticulated
python— Anaconda
BOIDAE
VIPERIDAE• Poisonous
(Haemotoxic - Affects blood)
• Body characteristics— Typical triangle
shaped head— Folding fangs — Head covered with
small scales and nostrils are placed vertically
• Examples ─ Copperheads,
cottonmouths and rattlesnakes
ELAPSIDAE• Poisonous (Neurotoxic -
Affects nerves)• Body characteristics
— Hollow fixed fangs in the jaw below or in front of the eyes
— Do not have the triangle shaped head
— Head covered with large scales
— Lateral Nostrils• Examples
— Cobras, mambas, kraits and the coral snake
KING COBRA • 18 feet• Head as large as man’s
hand• Hood • Six feet tall
HYDROPHIIDAE• Sea snakes• Majority are poisonous
(Neurotoxic – Affects nerves)
• Examples— Banded sea snake— Yellow bellied sea
snake
COMPARISON OF POISONOUS & NON-POISONOUS SNAKES
COMPARISON OF POISONOUS & NON-POISONOUS SNAKES
Scale arrangement
Single row
Double row
COMPARISON OF POISONOUS & NON-POISONOUS SNAKES
POISON GLANDS AND VENOM EXTRACTION
COMPARISON OF POISONOUS & NON-POISONOUS SNAKES
WATER SNAKES
WATER SNAKES• If just the head is
showing, it is probably a harmless water snake
• Almost all venomous snakes swim with their lungs inflated, leaving the majority of their bodies afloat
Characteristic Poisonous Nonpoisonous
Shape of head Triangular RoundPit (+) (-)Pupils Elliptical RoundBite marks Fang marks 2 rows of teethCaudal plates Single row Double row
Color body Red ring next to yellow Alternating color
Swim in water Most of the body afloat
Often only head showing
POISONOUS / NON POISONOUS SNAKES
POISONOUS SNAKES IN PAKISTAN• Rat Snake
(Ptyas mucosus) Local Name: - Dhaman
• Indian Python (Python molurus) Local Name: - Azdaha
• Indian Cobra
(Naja naja) Local Name: - Cobra
• Leaf-nosed Viper ( Eristocophis macmahoni) Local Name: - Cobra
RISK TO HUMANS• Species and size of the
snake• Venom injected• Localization of the
bites• Weight & general
health of the victim• Sensitivity to the
venom• The availability of
health facility
SIGNS AND SYMPTOMS• Local effects
Fang mark at the site of injection
Intense local pain Swelling Oozing out of haemolyzed blood Blisters may appear
SIGNS AND SYMPTOMS• General effects
Haemoglobinuria Petechial haemorrhages Bleeding from gums, mucus
membranes such as rectum and body orifices
Haemoptysis Cold, clammy skin Death due to circulatory failure
SIGNS AND SYMPTOMS• Myotoxic
At the site of bite no pain and swelling
Muscle weakness Ptosis develops Generalized muscle paralysis Urine is brown in colour Respiratory muscle weakness leads to
death Hyperkalemia may result in cardiac
failure
SIGNS AND SYMPTOMS• Neurotoxic
Lethargy , giddiness , muscular weakness and spreading paralysis
Increased salivation and vomiting Ptosis and paralysis of extra ocular
muscles Breathing becomes slow and laboured Patient remains conscious but unable
to speak Finally respiratory paralysis
consequently death
WHAT TO DOOn seeing the Snake• Remain calm and
cautious• Get out of the way• Call for help• Use stick to kill the
snake by keeping a safe distance and striking the head
If you are the Victim
• Be calm• Try not to move the
effected part much• Call for help• Move away from
snake• Prevent further bite• Nearest health
facility
WHAT TO DO
If you are the helper of the Victim
• Remain calm• Reassure the victim• Call for help• Move the patient to safety• Evacuate the patient to
the nearest health facility• Try to kill the snake with
the help of others
WHAT TO DO
• There are two important aspects of snakebite treatment, one is the first-aid and then the treatment (antivenom serum)
TREATMENT – SNAKE BITE
FIRST AID•Reassure
•Evacuate
•Splintage
•Tourniquet
TREATMENT •Allaying anxiety and fright•Prevention of spread of venom•Shifting the victim to medical aid center•Use of antivenin
TREATMENT •Allaying anxiety and Fright To prevent the shock due to fright it is
desirable to reassure the victim by clarifying that
All snakes are not poisonous Even poisonous snakes are not fully
charged with poison all the time Even a snake with fully charged with poison
does not always inject it’s lethal dose
TREATMENT
•Prevention of spread of Venom Immobilization Application of tourniquet Cleaning the wound Local emetine injection Incision and suction at the site
TREATMENT
•Prevention of spread of Venom Immobilization Application of tourniquet Cleaning the wound Local emetine injection Incision and suction at the site
TREATMENT •Wash the bitten surface with plain water without rubbing•Polyvalent anti-venom should be given•Antibiotic & Tetanus prophylaxis
TREATMENT •Anti – Venom Types
Specific antivenin Polyvalent antivenin
Strength of polyvalent antivenin is 1ml will neutralize 0.6mg of dried cobra
venom, 0.45mg of dried krait venom, 0.6mg of dried russel’s viper venom and 0.45mg of dried saw-scaled viper venom
TREATMENT
•Neutralize Toxin at Tissue Level Neostigmine and atropine
administration in elapid snakebite Heparin and fibrinogen in viper
snakebite•Contraindications Morphine and alcohol as these
depresses respiratory center
TREATMENT •General measures Artificial respiration Blood Transfusion Steroids Antihistamines Antibiotics Stimulants are helpful in paralytic cases Aspirin short acting barbiturates
TREATMENT • Anti – Snake Venom (ASV)
Anti–venom is immunoglobulin (usually the enzyme refined F(ab)2 fragment of IgG) purified from the serum or plasma of a horse or sheep that has been immunized with the venoms of one or more species of snake
TREATMENT
5 vials(50ml)5-10 vials(50-100ml)
10-20 vials(100-200ml)
TREATMENT • Repeat dose of Anti – Snake
Venom (ASV) Continuing absorption- due to
improved blood supply following correction of shock, hypovolaemia etc,
After elimination of antivenom A redistribution of venom from the
tissues into the vascular space
TREATMENT • At the earliest sign of a reaction
Antivenom administration must be temporarily suspended
Adrenaline-0.1% solution, 1 in 1,000, 1 mg/ml is the effective
treatment for early anaphylactic reactions
IV hydrocortisone (adults 100 mg, children 2 mg/kg body
weight). The corticosteroid is unlikely to act for several hours,
but may prevent recurrent anaphylaxis
Increasing evidence for anti H2 antihistamines-Ranitidine –
adults 50 mg, children 1 mg/kg
Start fluids, inotropes along with IV adrenaline for circulatory
collapse-
5-day course of oral antihistamine/ Prednisolone.Chlorpheniramine: 2 mg six hourly Prednisolone: 5 mg six hourly
Serumsickness
DON'TS •Tight tourniquets (Tight band / rope)•Incisions at the site of snake•Local suction•Application of herbal medicines, cow dung, seeds, saliva etc•Unnecessary delaying
• Always remain cautious, snakes may silently harbour anywhere
• Ankle boots be used, with trousers tucked in the socks
• Boots should be shaken before use
• Remove bushes, shrubs etc lying close to the buildings
• Alter all sites that provide cool, damp, dark habitat
• A stick and torch, be used at night
PREVENTION OF SNAKE BITES
PREVENTION OF SNAKE BITES
• Never reach in to holes or crevices
• Bedding & clothing should be thoroughly shaken
• Mosquito nets• Two feet deep and two
feet wide trench with vertical sides
• The trench or the sleeping platform should be thoroughly inspected
• Watch your step; very few snakes bite unprovoked
• Black Mamba Most deadly snake Located in Africa and is colored dark olive
or a dark brown color with black spotting along its back
Longest fangs Delivers quick multiple bites and flees Venom is a cardio toxin and a fully grown
Black Mamba can deliver 100mg to 120mg. A lethal dose of a cardio toxin to a human is
10mg to 15mg
WORLD DEADLIEST SNAKES
Black Mamba
• Common Krait Located mostly in Southeast Asia Normally black with yellow bands
around it Can go either on land or water Affects the nerves and produces a
nerve paralysis. Fangs are not very long so has to chew
on it’s pray to induce the venom into the blood stream
WORLD DEADLIEST SNAKES
Common Krait
• Russell’s Viper Located in South Asia Light brown with three rows of black
or brown spots bordered by yellow or white around
Responsible for the most fatalities Highly irritable, coils up before strike Damage to the blood cells and tissue
WORLD DEADLIEST SNAKES
Russell’s Viper
• Taipan Located in Australia Pale creamy color on the head Light brown, dark brown,
copper, or olive Usually stay away from humans Defend itself
WORLD DEADLIEST SNAKES
Taipan
• Cobra Located in South Asia Hood that pops up behind Symbol on the back, looks like
eyes Either spit venom or bite Spiting venom isn’t deadly Severe pain and damage to eyes
WORLD DEADLIEST SNAKES
AQ&Q u e s t i o n s
A n s w e r s