Snake

Poisonous Snakes - Introduction, Classification, Biting mechanism, Identification and dos and dont dos

1. Notochord–flexible rod like structure;
extending length of body

2. CLASSIFICATION OF CHORDATES
Snakes

3. SNAKES
Dr.K.RAMESHKUMAR
Assistant Professor
PG & Research Dept. of Zoology
Vivekananda College
Tiruvedakam West

4. OBJECTIVES
•Characteristics of Reptilia
•Systematic position of Snake
•Characteristics of Snake
•Biting Mechanism
•Snake Venom
•Effect of Venom
•Antivenine
•Poisonous Snakes of South India
•Management & Treatment

5. CHARACTERISTICS OF REPTILIA
Disliked animal group
First Land Vertebrates
Creeping Animals
Bilaterally Symmetry
Herpetology
Poikilotherms
Dry & Scales
Two Pairs of limbs
Heart –3 Chambers
Respiration –lungs
Carnivores
Uricotelic Animals
Sexual Dimorphism
Fertilization is Internal
Oviparous/Viviparous
Parental Care is absent

6. INTRODUCTION
•In Sanskrit snakes –Chakshushravaa
•In World, 300/3000species of snakes
•30000 to 40000 persons die of snake
bite in the world every year (WHO)
•In India, 69/330species of snakes
•15000 to 20000 persons die of snake
bite in the world every year (WHO)

7. SYSTEMATIC POSITION –
SNAKE
PHYLUM : Chordata
SUB PHYLUM : Vertebrates
CLASS : Reptilia
ORDER : Squamata
SUB ORDER : Ophidia/Serpentes

8. SNAKE-MORPHOLOGY
•Forked tongue
•The carnivore lifestyle
•Limbless body
•Cylindrical shape
•Extremely flexible
•Scaly skin
•Jacobson's organs
(organ of smell)
•Poikilotherms
•Pit organs enable a snake to detect the exact
location of another animal

9. POISON APPARATUS

10. BITING MECHANISM

11. •Lower Jaw are
loosely Connected
•Pectoral Girdle is
absent
•Bones are also
movable
•There is no sternum
•Ribs are free

13. SNAKEVENOM
Yellow or Greenish colour
Complex mixture of various enzymes and
specific toxins
Digestive juice
90% protein
Have 25 different enzymes found in
various venoms and 10 of these occur
frequently in most venoms

14. Cont…
Synergistic in effects: different venoms
contain different combinations of enzymes
causing a more potent effect than any of
the individual effects

15. COMPOSITION OF SNAKE
VENOM
Enzymes:
•Phospholipase A2(Lecithinase), 5’-nucleotidase,
collaginase, L-aminoacid oxidase, proteinases,
hyaluronidase,
•Phospholipase-b (Cobra)
•Endopeptidases, kininogenase, factor-X,
prothrombin activating enzyme (Viper)

16. Toxins:
•α-bungarotoxin, β-bungarotoxin, Crotoxin,
Crotamine, Cardiotoxin.
Peptide -Pyroglutamyl peptide
Nucleoside -Adenine, Guanine, Inosine.
Lipid -Phospholipid, Cholestrol
Amine –Histamine –engage the pathogen
infection
Serotonin –affect the brain function
Metal -Cu,Zn,Ni,Mg.

17. Mechanism of Toxicity of Venom
•The most common types of enzymes are
proteolytic, phospholipases and
hyaluronidases
–Proteolytic Enzymes: digestive properties
–Phospholipases: degrade lipids
–Hyaluronidases: facilitates venom spread through
out the body

18. Antivenom(Antivenine)
•Prepared from the blood of a horse, sheep, goat, or
rabbit
•Repeated injections for 6 months
•Doses are gradually increased
•Animal will undergo an immune responseto the
venom, producing antibodiesagainst the venom
•Collection of blood and serum separated
•Used to treat envenomation.
MILKING THE SNAKE TO MAKE
ANTI VENOM.

19. Poisonous Snakes
Classification of snakes
Three Families:
•1. Elapidae: Neurotoxic (Eg. Cobra,
Krait & Coral Snake)
•2. Viperidae: Haemotoxic (Eg. Viper,
Saw Scaled Viper)
•3. Hydrophidae: Myotoxic/Cytotoxic
(Eg. Sea Snake)

20. 1. ELAPIDAE
Najanaja(Cobra)
•Seen through out India,
Burma, Srilanka
•Brown/Black –6 feet
•Well marked hood
•Single (monocellate) or
double spectacle mark
•Oviparous

22. 1. ELAPIDAE
NajaHannah(King Cobra)
•Largest Poisonous Snake in
the World –18 feet
•Thick vegetation
•Dark Brown/Dark Black with
cross bands
•Feeds on other snakes
•Deadly poisonous

23. 1. ELAPIDAE
Bungarus(Krait)
•The fangs are short
and fixed.
•Steel blue coloured
with white cross bands.
•Hexagonal scales
•Nocturnal

24. 1. ELAPIDAE
Micrurus (Coral Snakes)
•Very colorful stripe
pattern
•Black nose
•5 feet
•Round pupils like
most non-venomous
snakes

25. 2. VIPERIDAE
A). PitlessVipers: They are
a) Russel‘s Viper
b) Saw-scaled Viper
B). Pit Vipers: They are
a) Pit Viper-Crotalidae
b) Common Green Pit Viper

26. 2. VIPERIDAE
Viperarusselli(PitlessViper)
•Large mobile fangs
•Diamond-shaped
markings
•Brown in colour, elliptical
patches in three rows on
body
•Triangular head
•Viviparous
•Nocturnal

27. 2. VIPERIDAE
Echiscarinata
(Saw Scaled Viper)
•Poor vegetation
•Small snake –2 feet
•Brown colourwith white
patches
•Arrow shaped marked

28. 3. HYDROPHIDAE
Hydrophis(Sea Snake)
•20 types of sea snakes
found in India.
•All are poisonous
•Tail is Oarshaped
•Myotoxic
•Ovoviviparous

29. DIFFERENCES BETWEEN COBRA
AND VIPER
Traits Cobra Viper
Body Usually long and
cylindrical
Usually short and stout
Head Small and covered with
large scales
Larger and broader than body,
covered with small scales
Eye It has round pupilIt has vertical pupil
Fangs. Short, fine and fixedLong, movable and strong,
Eggs Oviparous Viviparous
Tail Round Tapering
Venom Neurotoxic mainly Hemotoxic usually

30. SIGNS AND SYMPTOMS
Bites by Elapidae -Symptoms
●More virulent, attacking nerve centre's (Paralysis)
●Swelling, local pain & local necrosis (Cobra )
●Ptosis –Drooping of the upper eye lid
●Diplopia –double vision
●Ophthalmoplegia –Paralysis of the eye muscles
●Stomach pain ( Krait )
●Destruction of RBC
●Krait bites –present in early morning with paralysis
–can be mistaken for STROKE .

31. Cont…
Prof.K.N.Bahl
COBRA–Spinal Cord (CO) & Brain (BRA)
Coagulation of blood (COB) is reduced (R)
and death occurs by asphyxia (A)

33. Bites by Viperidae
Symptoms
●Severe local effects –as early as within 15 min of
bite
●Extensive Swelling –spreading quickly to involve
whole limb.
●Necrosis –destruction of tissue
●Hemostatic abnormality
●Abdominal Pain
●Passage of reddish/dark brown
urine/diminishing/ nil urine output
●Low back pain , indicative of early renal failure
●Renal failure –Viper

35. Bites by Hydrophidae
Symptoms
Local swelling
Rhabdomyolysis–damage of skeletal muscle
Myalgia–Muscle pain
Muscle stiffness
Myoglobinuria-Presence of myoglobin in the
urine
Paralysis (inability to move) legs
Excessive saliva production

36. Summary of ManifestationsFeature Cobras Kraits Russells
Viper
Saw
Scaled
Viper
Hump
Nosed
Viper
Local Pain/ Tissue Damage YES NO YES YES YES
Ptosis/ Neurological Signs YES YES YES! NO NO
Haemostatic abnormalities NO NO! YES YES YES
Renal Complications NO NO YES NO YES
Response to Neostigmine YES NO? NO? NO NO
Response to ASV YES YES YES YES NO

38. Incidence of snake bites
North India:
Elapidae
South India:
Viperidae

39. Site of snake bites
50%
32%
10%
8%
Lower limb
Upper limb
Eyebrow,abdomen,ear,neck,face
Unidentified bite area
•Thevictimswerebittenmostlyat
nightormidnight:
Nights58.73%
Daytime41.26%
•Asignificantnumberofcases
occurredwhilethevictimswere
asleep

40. Incidence of snake bite varies
with climate…
0.00%
10.00%
20.00%
30.00%
40.00%
50.00%
60.00%
Monsoon season Spring season Summer season Autumn season
Peak in July, August and
September
No bites
December, January and
February

41. Management
The first aid being currently recommended is based around the
mnemonic: “Do it R.I.G.H.T.”
R=Reassure the patient. 70% of all snakebites are from non-venomous
species. Only 50% of bites by venomous species actually envenomate
the patient.
I= Immobilisein the same way as a fractured limb. Use bandages or
cloth to hold the splints, not to block the blood supply or apply
pressure. Do not apply any compression in the form of tight ligatures,
they can be dangerous!
G.H. = Get to Hospital Immediately. Traditional remedies have NO
PROVEN benefit in treating snakebite.
T = Tell the doctor of any systemic symptoms such as ptosis that
manifest on the way to hospital.

42. Management
Management
Local
Specific
Supportive

43. Do’s in Snake Bite…
•Encouragement
•Relieve anxiety
•Call for help
•Wash with water and soap (gloves)
•Remove constricting clothes
•Take to hospital –May need AVS
•If possible; the dead/alive snake or photo too

44. Dont’s in Snake Bite…
•Waste time trying to kill the snake
•No cutting or sucking
•Do not apply any oils/home medications on
the wound
•Do not elevate the limb/keep below heart
level
•Do not tie with anything
•Assume the snake is non-poisonous

45. TREATMENT FOR SNAKE BITE
•Call for emergency assistance immediately if someone has
been bitten by a snake. Responding quickly in this type of
emergency is crucial. While waiting for emergency assistance:
•Wash the bite with soap and water.
Immobilize the bitten area and keep it lower than the heart.
Cover the area with a clean, cool compress or a moist dressing
to minimize swelling and discomfort.
•Give Anti venom.

46. Investigations
●Complete Blood Count–Anemia, Leucocytosis,
Thrombocytopenia, Hematocrit
●Evidence of Hemolysis–Fragmented RBCs
●Prolonged Clotting Time –ActivatedPartial
Thromboplastin Time (APTT)
●Serum Electrolytes –Hyperkalemia, Raised Urea,
Creatinine

47. Cont..
●Urine for RBC –Viper Bite –Hematuria,
Proteinuria, Hemoglobinuria, Myoglobinuria
●ECG–Normal, Bradycardia with ST elevation or
depression, T inversion, QT prolongation
●ABG–Hypoxemia with Respiratory Acidosis,
Metabolic / lactic Acidosis
●Chest X-ray –Normal, Pulmonary Oedema,
Intrapulmonary Hemorhages, Pleural
Effusion

48. Monitor Vital Signs
●Observe every patient for minimum 24 hours
●Pulse, BP, Respiration
●Urine output
●Blood urea, Creatinine
●Bleeding tendency
●Local swelling
●Vomiting
●Diplopia, Ptosis, Muscle Weakness, Breathlessness

49. LIST OF ANTIVENOM MANUFACTURERS
IN INDIA
1. Central Research Institute of Kasauli, HP*
2. Haffkine Biopharmaceutical Co., Mumbai,
MS *
3. Serum Institute of India Ltd., Pune, MS *
4. VINS Bioproducts Ltd., Andhra Pradesh
5. Kings Institute of Preventive Medicines,
Chennai*
6. Bharat Serums & Vaccines Ltd., Mumbai
*Approximately 5 lakh vials are produced
annually.

50. Adsorption of venom onto site:





Adsorption of antivenom onto site:





where:
V = venom
A = antivenom
S = unoccupied receptor site
VS = site occupied by venom
AS = site occupied by antivenom
AV = neutralized product from venom/antivenom reaction

Reaction of venom with antivenom on site:



Reaction of antivenom with venom on site:



Reaction of venom and antivenom in blood:



Removal of product and reactants from system:

52. Questions