Public Health Prevention, management & treatment of snake bite.

1. SNAKE BITE
by
Dr. Rizwan Saeed

2. SCIENTIFIC CLASSIFICATION
Kingdom: Animalia
Phylum: Chordata
Subphylum: Vertebrata
Class: Reptilia
Order: Squamata
Suborder: Serpentes /ophedia (venemous)
Linnaeus, 1758

3. Snakes are elongate legless carnivorous
reptiles of the suborder Serpentes that
can be distinguished from legless lizards
by their lack of eyelids and external ears.

4.  Snake bite is primarily a problem of the
 poorer rural populations
 farming activities.
 Poor access to health services
 fail to reach hospital in time.
 Hospital statistics on snakebites therefore
underestimate the true burden.
 In addition to mortality, some snakebite victims
survive with permanent physical squeal due
to local tissue necrosis and, sometimes
psychological squeal.
 Because most victims are young, the
economic impact of snakebite can be
considerable.

5. •Living snakes are found on every continent except
Antarctica.
•15 families
•456 genera
• over 2,900 species.
• range in size from the tiny, 10 cm long thread snake to
pythons and anacondas of up to 7.6 metres (25 ft) in
length.
•Most species are non-venomous and those that have
venom use it primarily to kill and subdue prey rather
than self-defense.
•Some possess venom potent enough to cause painful
injury or death to humans.

6. EVOLUTION
 150 million-year-old specimens, readily
identifiable as snakes, yet with lizard-like
skeletal structures, have been uncovered in
South America and Africa. There is
consensus, on the basis of comparative
anatomy, that snakes descended from
lizards.
 Fossil evidence suggests that snakes may
have evolved from burrowing lizards

7. VENOM
The term poisonous snake is mostly incorrect—
poison is inhaled or ingested whereas venom is
injected
Vipera berus, one fang in
glove with a small venom
stain, the other still in place
Cobras, vipers, and closely
related species use venom
to immobilize or kill their
prey. The venom is
modified saliva, delivered
through fangs
•DRY BITE
The standard way of estimating the strength of any toxin is to inject a
thin solution into standard size laboratory mice, to establish a LD50
dose, i.e. a dose that on average will kill half of the mice in 24 hours

8. Snake venoms
complex mixtures of proteins and are stored
in poison glands at the back of the head.
•These proteins can potentially be a mix of
•neurotoxins (which attack the nervous
system),
•hemotoxins (which attack the circulatory
system),
•Cytotoxins (cell),
•bungarotoxins(NEUROTOXIN PROTEINS-KRAITS)
and many other toxins that affect the body in
different ways.

9.  Almost all snake venom contains
hyaluronidase, an enzyme that ensures rapid
diffusion of the venom

10. SNAKE BITE
 The most common symptoms of all
snakebites are
panic, fear and emotional instability, which
may cause symptoms such as
nausea and vomiting, diarrhea,
 vertigo,
fainting,
tachycardia, and cold, clammy skin.
 Television, literature, and folklore are in part
responsible for the hype surrounding
snakebites, and a victim may have
unwarranted thoughts of imminent death.

11. SEQULAE OF SNAKE BITE
 NO EFFECT
 PSYCHOGENIC EFFECT
 ENVENOMATION
 NEUROTOXIC SEQULAE
 MYOTOXIC EFFECTS
 SEQULAE OF WRONG INDIGENOUS
PROCEDURES
 OTHER COMPLICATIONS
 COMPLICATIONS OF TOURNIQUET
 COMPLICATIONS OF INCISIONS
 WOUND SEPSIS
LOCAL EFFECT
HAEMOTOXIC

12.  i) cytotoxins causing local swelling
and tissue damage,
 ii) haemorrhagins which disturb the
integrity of blood vessels,
 iii) compounds which lead to
incoagulable blood,
 iv) neurotoxins causing in
neurotoxicity
 v) myotoxins which cause muscle
breakdown

13. Dry snakebites,
Those inflicted by a non-venomous species,
are still able to cause severe injury to the
victim.
a snakebite which is not treated properly
may become infected the bite may cause
anaphylaxis in certain people, and the
snake's saliva and fangs may harbor many
dangerous microbial contaminants,
including Clostridium tetani.
 If neglected, an infection may spread and
potentially kill the victim.

15. INOCULATION / INJECTION BY
SNAKE
ENTERS SURROUNDING
TISSUE
CAPILLARRY ABSORPTION
LYMPHATI
C
BLOOD
VESSELS
TARGET ORGANS SYSTEMIC
EFFECT
RECOVE
RY
DEAT
H
•AUTO-PHARMACOLOGICAL
MANIFESTATION
•DIRECT VENOM ACTION

16.  Most snakebites, whether by a venomous snake or
not, will have some type of local effect.
 In over 90% of cases there is minor pain and
redness, but this varies depending on the site.
 Bites by vipers and some cobras may be extremely
painful, with the local tissue sometimes becoming
tender and severely swollen within 5 minutes.
 Other common initial symptoms of pit viper bites
include lethargy, weakness, nausea, and vomiting.
Symptoms may become more life-threatening over
time, developing into hypotension, tachypnea,
severe tachycardia, altered sensorium, and
respiratory failure

17. Australian Elapids ,
Viper
coagulopathy
Cobras, Kraits,
Mambas, Sea
snakes
Neurotoxicity
Victim not treated
May die of
Respiratory failure

18.  necrosis of muscle tissue
 Muscle tissue will begin to die throughout the
body, a condition known as rhabdomyolysis.
 Dead muscle cells may even clog the kidney
which filters out proteins. This, coupled with
hypotension, can lead to acute renal failure,
and, if left untreated, eventually death

19.  Interestingly, bites caused by the
rattlesnake, coral snake, and the speckled
rattlesnake reportedly cause little or no pain
despite being serious injuries.
 Victims may also describe a "rubbery,"
"minty," or "metallic" taste if bitten by certain
species of rattlesnake.
 Spitting cobras and rinkhalses can spit
venom in their victims' eyes. This results in
immediate pain, ophthalmoparesis, and
sometimes blindness

20. •Snakes do not ordinarily prey on humans and
most will not attack humans unless the snake
is startled or injured, preferring instead to
avoid contact.
•non-venomous snakes are usually not a
threat to humans. venomous snakes present
far greater hazard to humans
•Snakes are most likely to bite
when they feel threatened, are
startled, provoked, or have no
means of escape when cornered

21. DEATH WITH SNAKE BITE
Documented deaths resulting from snake bites
are uncommon. Non-fatal bites from venomous
snakes may result in the need for amputation of
a limb or part thereof. Of the roughly 725 species
of venomous snakes worldwide, only 250 are
able to kill a human with one bite.

23. TREATMENT
 The treatment for a snakebite is as variable as the bite itself. The
most common and effective method is through antivenom, a
serum made from the venom of the snake.
 Some antivenom is species specific (monovalent) while some is
made for use with multiple species in mind (polyvalent).
 In the United States for example, all species of venomous snakes
are pit vipers, with the exception of the coral snake.
 To produce antivenin, a mixture of the venoms of the different
species of rattlesnakes, copperheads, and cottonmouths is
injected into the body of a horse in ever-increasing dosages until
the horse is immunized. Blood is then extracted from the
immunized horse and freeze-dried. It is reconstituted with sterile
water and becomes antivenin. For this reason, people who are
allergic to horses cannot be treated using antivenin.
 Antivenin for the more dangerous species (such as mambas,
taipans, and cobras) is made in a similar manner in India, South
Africa, and Australia with the exception being that those
antivenins are species-specific.

24.  Keep the victim calm, restrict movement.
 • The limb, which has been affected by the
bite, should be immobilized with splint and be
kept below the level of the heart. A
compression bandage (not tight) should cover
the entire limb with the splint.
 • Assure the victim and do not let him panic.
When under panic, it will enhance heart rate
and would circulate the venom faster in the
body.
 • Remove any rings or constricting items; the
affected area may swell.
 • A snakebite victim is under tremendous
psychological stress. It is necessary to keep
the patient warm. However, no alcohol/hot
beverages should be given. The patient

25.  • DO NOT COVER THE BITE AREA AND
PUNCTURE MARKS. The wound should be
gently cleaned with antiseptic.
 • Try to aspirate the venom out of the puncture
marks with standard suction devices. It has
been identified that a suction more than 270
mmHg can initiate the flow from the puncture
marks. Suction instruments often are included in
commercial snakebite kits. But, the suction
should be applied within 5 minutes of the bite.
 • The only remedy for venomous
snakebite is the anti-venom serum, which
is available at most government hospitals and
public health centers. Some private nursing
homes have also started stocking it and treat
snakebite cases.

26. Snake trapping
The tribals of "Irulas" from Andhra Pradesh and Tamil
Nadu in India have been hunter-gatherers in the hot dry
plains forests and have practiced this art for
generations. They have a vast knowledge of snakes in
the field. Irulas generally catch the snakes with the help
of a simple stick
•SNAKE SKIN
•SNAKE VENOM

27. PETS : BALL PYTHON & CORN SNAKE

28. SYMBOLISM
Medusa by 16th Century
Italian artist Caravaggio
Rod of Asclepius, in which the
snakes, through ecdysis, symbolize
healing.

29. HISTORY / RELEGION
•In Egyptian history, the snake occupies a primary
role with the Nile cobra adorning the crown of
the pharaoh in ancient times. It was worshipped
as one of the gods and was also used for sinister
purposes: murder of an adversary and ritual
suicide (Cleopatra).
•The snake is one of the 12 celestial animals of
Chinese Zodiac, in the Chinese calendar.
•The cobra is seen on the neck of Shiva and
Vishnu is depicted often as sleeping on a
seven-headed snake or within the coils of a
serpent

31. SNAKEBITES
Poisonous snakes in the U.S.
Rattlesnake
Copperhead
Water moccasin
Coral snake

32. PIT VIPERS
 Rattlesnake
 Copperhead
 Water moccasin
 Characteristics:
 Flat heads that are wider than their necks
(triangular)
 “Cat eyes” (elliptical)
 Heat sensitive “pit” between the eye and nostril
on each side of the head

33. PIT VIPER BITES: SIGNS AND SYMPTOMS
 Severe burning/ fang marks
 Swelling (occurs in 5 minutes and can
involve entire extremity)
 Mark extent of swelling on body
 6-10 hours later: potential discoloration and
blood filled blisters

34. CORAL SNAKE BITES
 Most venomous, but rarely bites
 Red, yellow and black band
 Every other band is yellow
Red on yellow, kill a fellow. Red
on black, venom lack.
 Chews venom into the body

35. Cobra viper
1 Venom is neurotixic venom is vasculotoxic
2 Injects almost all venom Injects little venom
3 Local symptoms are mild Intense local pain and cellulitis
4 Effects are mainly on CNS Effects are mainly on CVS
5 Lay eggs Give birth to living ones
6 Pupils are circular Pupils are elliptical
7 head and neck of same width
Head usually with small scales
& neck narrow

36. SNAKE BITES: WHAT TO DO (CONTROVERSIAL
BUT GENERALLY RECOMMENDED)
 Pit Viper
 Get away from snake / may re-strike
 Can strike ½ the length of their body
 A decapitated head can react for 20 more minutes
 Have victim lie down and stay calm
 Do not move victim unless absolutely necessary
 Keep bitten area immobile and below the level of
the heart
 Call 1122
 Wash area with soap and water

37. SNAKE BITES: WHAT TO DO #2
If more than 1 hour from medical
facility, use “extractor” within 3
minutes and left on for 30 minutes (pit
vipers only)
(up to 30% of venom may be removed)
Seek medical attention immediately
Anti-venom available only at hospitals
Same anti-venom used no matter type of
snake
Must be given within 4 hours of the bite

38. Icing is generally not helpful
“Cut and suck method”
 Increases risk of infection
No constriction bands
 gangrene
 (bite on local woman)
Old style snake bite kit that should NOT be used

39. Application of a tourniquet to the bitten
limb is generally not recommended. There is
no convincing evidence that it is an effective
first aid tool as ordinarily applied. Uninformed
tourniquet use is dangerous, since reducing
or cutting off circulation can lead to
gangrene, which can be fatal
Cutting open the bitten area, an action often
taken prior to suction, is not recommended
since it causes further damage and increases
the risk of infection.

40. • No application of potassium permanganate
• Use of electroshock therapy. Although still advocated
by some, animal testing has shown this treatment to be
useless and potentially dangerous

41.  Until the advent of antivenom, bites from
some species of snake were almost
universally fatal. Despite huge advances in
emergency therapy, antivenom is often still
the only effective treatment for
envenomation.
 The first antivenom was developed in 1895
by French physician Albert Calmette for the
treatment of Indian cobra bites
 Immunization against snake venom ?

42. ANTIVENOM

43. SUPPORTIVE AND SYMPTOMATIC MEASURES
 Bed rest
 Warmth
 Analgesics and sedatives (codeine,
meperedine avoid morphine d˚ risk of respiratory
failure)
 Shock (fluid electrolyte balance, blood transfusion)
 Ventilation support (O2 in hypoxia- neurotoxin, tracheotomy)
 Antibiotics
 Tetanus- gas gangrene prophylaxis
 Heparin (in DIC evidence in hemolysis, Hb
drop)
 Steroids (deals allergic manifestations of

44. CORAL SNAKE BITES: WHAT TO DO
Coral Snake
Use same methods except:
Do not use “extractor”
Apply mild pressure over the bite site
and wrap entire limb with an ace
bandage
No ice is necessary

45. NON-POISONOUS BITES
 Horse shoe shaped tooth marks
 May be painful but no systemic
reactions
 What To Do?
Minor wound treatment
If in doubt, go to hospital or call Dr.

46. PREVENTION
Sign at Sylvan
Rodriguez Park in
Houston, Texas warning
of the presence of
snakes

47. SNAKE BITE PREVENTION
 Use caution around wood piles, rock crevices etc.
 Watch where you step
 Do not reach into holes or hidden ledges
 Wear boots (50%BITES BELOW KNEE), long pants, long
sleeved shirts
 Don’t sit or step over logs without checking it out
 Use a walking stick, Torches
 When camping, keep tent zipped at all times (float trip)
(child sat on snake)
 Take a friend along
 Stay out of tall grass
 Leave snakes alone
 Public education (first aid management)

48. PREVENTION (CONT..)
 1) Any unknown snake is potentially dangerous; do not play,
avoid any contact with any snake including those of small
size, baby, lethargic, dead. A cut off head can keep
poisonous activities for several minutes. Make yourself
familiar with the description of poisonous snakes in the
place where you live.
 2) Attention!!! Use torchlight at night – all local poisonous
snakes are active in the evening and at night. Pay more
attention in the forest, close to bushes, tall plants, etc.
 3) Snakes usually don't bite you without alarm:
 - Cobra – lifts vertically front part of the body (1/3), opens
hood, makes hiss, rushes to the aim.
 - Vipers - make a spiral from a tail, bend like zigzag front
part of the body, and make a strong hiss.
 4) If you meet a snake, go back slowly, don't do sudden
movements, do not turn your back to the snake, do not run,
and give the possibility for a snake to go away

49.  Reassurance and immobilization of the affected limb with prompt
transfer to a medical facility are the cornerstones of the
immediate care of snakebite.
 Pressure immobilization is used for some elapid species. The
mainstay of treatment of snakebite is the infusion of an
appropriate antivenom. Snake venoms are diverse, and therefore
the efficacy of antivenoms is geographically and biologically
restricted, meaning that a large number of antivenoms have been
developed for use in different settings
 Antivenoms are manufactured by immunizing horse or sheep
with venom from a particular species and then processing the
serum from the animal.
 Both monospecific and polyspecific antivenoms are
available; monospecific antivenoms are produced using the venom
of a single species, whereas polyspecific antivenoms are produced
against the venoms of several species that are prevalent in a
geographic region.
 In the rural tropics, victims are often bitten in an
agricultural field or jungle, and in many instances the
biting species is not identified. In such situations,
treatment with polyspecific rather than monospecific
antivenoms may be more appropriate

50. SNAKES: ADDITIONAL INFORMATION
 Poor vision, especially when shedding
 Prime time for crawling snakes in this area:
August
 Baby snakes have stronger venom
 Snakes just out of hibernation have stronger
venom
 Many organizations, including the American
Medical Association and American Red Cross,
recommend washing the bite with
soap and water. However, do not attempt
to clean the area with any type of chemical

51.  To train farmers, students and traditional
healers in first-aid for snakebite
 To discourage dependency on traditional
healers
 To familiarize people with venomous snake
 To know the impact of snakebite first-aid
education.
We need to :

52. Pressure immobilization

53. EPIDEMIOLOGY
Worldwide, snakebites occur
most frequently in the summer
season when snakes are active
and humans are outdoors.
Agricultural and tropical regions
report more snakebites than
anywhere else. Victims are
typically male and between 17
and 27 years of age. Children
and the elderly are most likely to
die
HIGHEST SNAKE BITE
DEATHS IN SIRILANKA =33000
(2008)

55. COBRA MAP PAKISTAN

56. DEATH / 100,000 DUE TO SNAKE BITE
•PAKISTAN = 1.90
•INDIA = 5.40
•BURMA = 15.40
•TRINIDAD & TOBAGO = 2.49
(2007)

57. •Most snakebites are caused by non-venomous snakes.
Of the roughly 3,000 known species of snake found
worldwide, only 15 % are considered dangerous to
humans
•Since reporting is not mandatory in many
regions of the world, snakebites often go
unreported.

58. CONCLUSION
snakebite mainly affects the rural men of
developing countries.
 Availability of anti-venom at primary healthcare
centre's and rapid transportation facilities may
change the morbidity associated with snakebites.
Early administration of the polyvalent anti-venom
has reduced morbidity and mortality but is associated
with anaphylaxis in small group of patients.
There is need to educate the rural population about
the hazards and treatment of snake bites.
randomized controlled trials are needed to
investigate
the issue of rationale of anti-venom treatment.

59. REMEMBER
• As a common man, one should know how to administer
proper first-aid to a snakebite victim, without losing precious
time.
• Never try to assess whether it was venomous snakebite or
not. As a layman one should treat every snakebite as
venomous snakebite, as some snake venom (like that of
common krait) does not show immediate effect even in the
case of a serious bite, it is wise to rush to a hospital.
• Even if in doubt about whether it is a snakebite or not, do
the first-aid and rush the victim to the nearest hospital.
• Educate your children that putting one's hand into any kind
of burrow could be dangerous.

60. • Never get into a dark bathroom; first switch on a light and
then see around you before you enter.
• Not all bites from venomous snakes lead to death; many
venomous snakes (and as many as 85% of snakes are non
venomous) deliver only a dry bite to humans. Even in the case
of a full bite, with appropriate first-aid, care and treatment a
snake bite victim can fully recover. Very few venomous
snakebites are fatal. Just as every mosquito bite does not
cause malaria, so every snakebite does not cause death.
• No attempt should be made to kill the snake to carry it along
to the hospital. It would result in delaying the arrival of the
patient to the hospital and is potentially dangerous for the
person who will attempt killing the snake. Qualified doctor can
diagnose observing the patient for clinical symptoms and
pathological tests.

61. All snakes are not venomous – so every snakebite is
not going to result in death – it would save people
from quacks. And reduce the amount of panic and
chaos.
Even a venomous bite is not always fatal – because
the severity of snakebite depends on many factors
like the size of the snake, whether the bite could be
completed, whether it was a dry bite or not, the age,
physique and affected limb of the victim.
First Aid would enable a person to buy more time to
reach medical aid on time.
The only cure which is available is anti-venom
serum injection and not quacks.
First Aid - if not done properly could cause more

62. #1 - Taipans (genus Oxyuranus)
#2 - Krait (Bungarus
coeruleus)
TOP FIVE DEADLIEST SNAKES
#3 - Philippine Cobra (Naja naja philippinensis)
#4 - King cobra (Ophiophagus hannah)
#5 - Russell's viper (Daboia russelli)

63. THANK YOU