2. OVERVIEW
•According to WHO, bites by animals carrying venoms, toxins and
pathogens are a significant cause of morbidity and mortality
worldwide.
•Globally, up to 5 million people are bitten by snakes annually, with
nearly 50% of them ending up with envenomation – mostly in Africa
and South-East Asia – necessitating prompt medical intervention with
appropriate antivenom.
•Dog bites account for tens of millions of injuries annually; the highest
risk is among children.
•Rabies is a significant health concern following dog, cat, bat or
monkey bites.
3. • The health impacts of animal bites vary with the type and
health of the animal species, the size and health of the bitten
person, and accessibility to appropriate health care.
• Paediatric cases are of particular concern related to animal bite
injuries, with over half of the victims being children.
• While numerous animal species have the potential to bite
humans, incidents involving domestic animals are significantly
more prevalent than those involving wildlife, and subsequent
infections from wounds can lead to severe illness or even death.
• In general, the key to better outcomes related to animal bites is
timely presentation of the bitten person for appropriate medical
attention and accurately identifying the animal attacked.
Animals of common concern:
• snakes
• dogs
• other vertebrates: cats, monkeys, rodents, bats.
6. INTRODUCTION
•A snakebite is an injury caused by a bite from a
snake, often resulting in puncture wounds
inflicted by the animal's fangs and sometimes
resulting in envenomation/ophitoxaemia
8. EPIDEMIOLOGY
• Estimate vary from 1.2 to 5.5 million snakebites, 421,000 to
2.5 million envenomings, and 20,000 to 125,000 deaths
globally.
• According to Deikumah JP et. Al (2023), In Northern Ghana,
there were an estimated 86 envenomings and 24
deaths/100,000/year caused mainly by Echis ocellatus [5]
while other studies in the Brong-Ahafo Region of Ghana
found snakebite incidence of 92/100,000.
9. CAUSES
• Snake bite is an important occupational injury affecting
farmers, plantation workers, herders, and fishermen.
• They often happen when a person steps on the snake or
approaches it too closely.
• Open-style habitation and the practice of sleeping on the
floor also expose people to bites from nocturnal snakes.
• The incidence of snake bites is higher during the rainy
season and during periods of intense agricultural activity .
• Snake bite incidence and mortality also increase sharply
during extreme weather events such as floods.
10. PATHOPHYSIOLOGY
• A widespread belief is that snake bites inevitably result in
envenoming.
• However, bites by nonvenomous snakes are common and bites by
venomous species are not always accompanied by the injection of
venom (dry bites).
• Since envenomation is completely voluntary, all venomous snakes are
capable of biting without injecting venom into a person.
• Snakes may deliver such a "dry bite" rather than waste their venom
on a creature too large for them to eat, a behaviour called venom
metering.
11. • Some dry bites may also be the result of imprecise timing on
the snake's part, as venom may be prematurely released
before the fangs have penetrated the person.
• Even without venom, some snakes, particularly large
constrictors can deliver damaging bites; large specimens
often cause severe lacerations, or the snake itself pulls away,
causing the flesh to be torn by the needle-sharp recurved
teeth embedded in the person.
• While not as life-threatening as a bite from a venomous
species, the bite can be at least temporarily debilitating and
could lead to dangerous infections if improperly dealt with.
12. • When envenoming does occur, it can be rapidly life-threatening.
• Snake venom is a complex mixture of toxins and enzymes, each of which may
be responsible for one or more distinct toxic actions.
• Classification of venemous snakes can be done on the basis of constituent of
venom & assosiated clinical signs:
• NEUROTOXIC : Local symptoms: parasthesias, neuropathic pain, Systemic symptoms: Ptosis, external
ophthalmoplegia, facial paralysis, paralysis of tongue, inability to open mouth, bulbar and respiratory
paralysis
• HAEMOTOXIC: painful progressive swelling and tissue destruction, Systemic symptoms: Spontaneous systemic
haemorrhage (gums, gut, brain, etc)
• MYOTOXIC: Local symptoms: Swelling /Oedema, subcutaneous bleed, Systemic symptoms: Trismus,
stiff painful muscles, myoglobinuria, rhabdomyolysis /muscle necrosis
• CARDIOTOXIC: Hypotension, cardiogenic shock, arrhythmias with sinus node dysfunction, ECG
abnormalities, raised serum/cardiac enzymes with acute myocardial infarction and/ or ischaemia,
myocarditis and acute pulmonary oedema
• CYTOTOXIC: Massive local swelling, blistering, necrosis: extravasation of blood and plasma
potentially causing hypovolaemia
• PROCOAGULANT: incoagulable blood with haematemesis and persistent bleeding from trauma sites
and recent wounds
13. • Quantity of venom injected at a bite
This is very variable, depending on the species
and size of the snake, the mechanical efficiency
of the bite, whether one or two fangs
penetrated the skin and whether there were
repeated strikes.
Although large snakes tend to inject more
venom than smaller specimens of thesame
species, the venom of smaller, younger vipers
may be richer in some dangerous components,
such as those affecting haemostasis.
14. • Therefore Bites by small snakes should not be ignored
or dismissed.
• They should be taken just as seriously as bites by large
snakes of the same species
• Composition of venom
Snake venoms contain more than 20 different
constituents, mainly proteins, including enzymes and
polypeptide toxins.
16. Signs and symptoms
• The most common symptoms of all snakebites are overwhelming fear,
which may cause symptoms such as nausea and vomiting, diarrhea,
vertigo, fainting, tachycardia, and cold, clammy skin.
• Dry snakebites, and those inflicted by a non-venomous species, can
still cause severe injury. There are several reasons for this: a snakebite
may become infected with the snake's saliva and fangs sometimes
harboring pathogenic microbial organisms, including Clostridium
tetani. Infection is often reported with viper bites whose fangs are
capable of deep puncture wounds. Bites may cause anaphylaxis in
certain people.
17. LOCAL SYMPTOMS AND SIGNS IN THE BITTEN PART
fang marks
local pain
local bleeding
bruising
lymphangitis
lymph node enlargement
Inflammation (swelling,
redness, heat)
blistering
local infection, abscess
formation
necrosis
18. Local bleeding from fang marks
Local swelling and bruising
along with blistering
Tissue necrosis
19.
20. MANAGEMENT
• First aid treatment
• Transport to hospital
• Rapid clinical assessment and resuscitation
• Detailed clinical assessment and species
diagnosis
• Investigations/laboratory tests
• Antivenom treatment
• Observation of the response to antivenom:
decision about the need for further dose(s) of
antivenom
• Supportive/ancillary treatment
21. • Treatment of the bitten part
• Rehabilitation
• Treatment of chronic complications
22. First aid treatment
• Protect the person and others from further bites.
• While identifying the species is desirable in certain regions, risking further
bites or delaying proper medical treatment by attempting to capture or kill
the snake is not recommended.
• Keep the person calm.
• Acute stress reaction increases blood flow and endangers the person.
• Call for help to arrange for transport to the nearest hospital emergency
room, where antivenom for snakes common to the area will often be
available.
23. • Make sure to keep the bitten limb in a functional
position and below the person's heart level so as
to minimize blood returning to the heart and
other organs of the body.
• Do not give the person anything to eat or drink.
• This is especially important with consumable
alcohol, a known vasodilator which will speed up
the absorption of venom.
• Do not administer stimulants or pain
medications, unless specifically directed to do so
by a physician.
24. • Remove any items or clothing which may
constrict the bitten limb if it swells (rings,
bracelets, watches, footwear, etc.)
• The bitten limb should be immobilized with a
makeshift splint or sling, and kept below the
level of heart.
• Keep the person as still as possible. Walking is
contraindicated, because muscular contractions
promote venom absorption.
25. • Tight (arterial) tourniquets are not
recommended!
Traditional tight (arterial) tourniquets. To be
effective, these had to be applied around the
upper part of the limb, so tightly that the
peripheral pulse was occluded. This method was
extremely painful and very dangerous if the
tourniquet was left on for too long (more than
about 40 minutes), as the limb might be
damaged by ischaemia.
26. • Constriction bands can be applied if there is no
nearby medical facility.
• Constriction bands can be used but loose
enough that a finger can slide beneath.
• Ideally, compression bandages should not be
released until the patient is under medical care
in hospital, resuscitation facilities are available
and antivenom treatment has been started.
• Suction and incision are dangerous and should
not be done.
27. Rapid clinical assesment
• Check for
- Airway
- Breathing
- Circulation
- Disability
• Cardiopulmonary resuscitation may be needed, including
administration of oxygen and establishment of intravenous access.
28. Detailed clinical assessment &
Species diagnosis
• History
- In what part of your body have you been bitten?
Evidence of snake bite, Assess nature & extent of local signs
-When were you bitten?
Assess the severity
-Where is the snake that bit you?
Identification of snake
29. •Non Poisonous Snakes
Head - Rounded
Fangs - Not present
Pupils - Rounded
Anal Plate - Double row of plates
Bite Mark - Row of small teeth.
•Poisonous Snakes
Head - Triangle - except Cobra
Fangs - Present
Pupils - Elliptical pupil
Anal Plate - Single row of plates
Bite Mark - Fang Mark
Identification of snake
30. • Physical examination
1.Examination of the bitten part
- Extent of swelling, extent of tenderness to
palpation noted, Lymph nodes draining the limb
should be palpated.If possible, intracompartmental
pressure should be measured and the blood flow
and patency of arteries and veins assessed.
- Early signs of necrosis may include blistering,
demarcated darkening or paleness of the skin, loss
of sensation and a smell of putrefaction (rotting
flesh).
31. 2.General examination
- Measure the blood pressure and heart rate.
- Examine the skin and mucous membranes for
evidence of petechiae, purpura, ecchymoses and,
in the conjunctivae, chemosis.
- Examine the gingival sulci -may show the earliest
evidence of spontaneous systemic bleeding.
- Examine the nose for epistaxis.
- Abdominal tenderness may suggest
gastrointestinal or retroperitoneal bleeding.
32. • Check the muscles innervated by the cranial
nerves(facial muscles, tongue, gag reflex etc).
The muscles flexing the neck may be
paralysed,giving the “broken neck sign”.
Broken Neck Sign in Russel”s Viper Bite
33. Investigations/ Laboratory diagnosis
• 20 minute whole blood clotting test (20WBCT)
-Very useful and informative bedside test requires very little skill and
only one piece of apparatus - a new, clean, dry, glass vessel (tube or
bottle).
-Place a few mls of freshly sampled venous blood in a small glass
vessel & Leave undisturbed for 20 minutes at ambient temperature
-Tip the vessel once.If the blood is still liquid (unclotted) and runs out,
the patient has hypofibrinogenaemia(“incoagulable blood”) as a
result of venom-induced consumption coagulopathy.
34. • Haemoglobin concentration/haematocrit:
a transient increase indicates
haemoconcentration resulting from a
generalised increase in capillary permeability(eg
in Russell’s viper bite). More often, there is a
decrease reflecting blood loss or, in the case of
Russell’s viper bite, intravascular haemolysis.
• Platelet count: this may be decreased in victims
of viper bites.
• White blood cell count: an early neutrophil
leucocytosis is evidence of systemic envenoming
from any species.
• Bleeding Time should be done to rule out any
bleeding abnormalities.
35. • Plasma/serum may be pinkish or brownish if there is
gross haemoglobinaemia or myoglobinaemia.
• Arterial blood gases and pH may show evidence of
respiratory failure (neurotoxic envenoming) and
acidaemia (respiratory or metabolic acidosis).
• Desaturation: arterial oxygen desaturation can be
assessed non-invasively in patients with respiratory
failure or shock using a finger oximeter.
• Urine examination: the urine should be tested by
dipsticks for blood/haemoglobin/myoglobin.
Massive proteinuria is an early sign of the
generalised increase in capillary permeability in
Russell’s viper envenoming.
36. Antivenom treatment
• The first antivenom was developed in 1895 by
French physician Albert Calmette for the
treatment of Indian cobra bites.
• Antivenom 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 immunised with the venoms of
one or more species of snake.
• Antivenom is injected into the person
intravenously, and works by binding to and
neutralizing venom enzymes. It cannot undo
damage already caused by venom, so antivenom
treatment should be sought as soon as possible.
37. • They can be either monovalent or polyvalent,
depending on the number of species (single or
multiple, respectively) whose venoms are used for
immunization.
• Although monovalent antivenom has often been
considered more efficacious, the production of
polyvalent antivenom is preferred in many countries
as snake species identification is generally not
possible for the attending physician.
• Local administration & Intramuscular Injection of
antivenom is not recommended!
• Snakes inject the same dose of venom into children
and adults. Children must therefore be given exactly
the same dose of antivenom as adults.
38. • Epinephrine (adrenaline) should always be
drawn up in readiness before antivenom is
administered to counter the reactions such as:
-Early anaphylactic reactions: usually within
10-180 minutes of starting antivenom , the
patient begins to itch (often over the scalp) and
develops urticaria, dry cough , fever, nausea,
vomiting, abdominal colic, diarrhea and
tachycardia.
-Pyrogenic (endotoxin) reactions usually
develop 1-2 hours after treatment .Symptoms
include shaking chills (rigors), fever,
vasodilatation and a fall in blood pressure.
Febrile convulsions may be precipitated in
children.
39. • Late (serum sickness type) reactions develop 1-12
(mean 7) days after treatment . Clinical features
include fever, nausea, vomiting, diarrhea, itching,
recurrent urticaria , arthralgia, myalgia,
lymphadenopathy, periarticular swellings,
mononeuritis multiplex,proteinuria with immune
complex nephritis and rarely encephalopathy.
• Criteria for repeating the initial dose of antivenom:
-Persistence or recurrence of blood incoagulability
after 6 hr of bleeding after1-2 hr.
-Deteriorating neurotoxic or cardiovascular signs
after 1-2 hr.
40. SUPPORTIVE/ANCILLARY TREATMENT
• The management of envenomed snake bites is not limited to the
administration of antivenoms.
• In the case of neurotoxic envenoming, artificial ventilation and
careful airway management are crucial to avoid asphyxiation in
patients with respiratory paralysis.
• A booster dose of tetanus toxoid should be administered but only in
the absence of coagulopathy.
41. • Bacterial infections can develop at the bite site,
especially if the wound has been incised or
tampered with nonsterile instruments, and may
require antibiotic treatment.
• Necrosis on the bitten limb may require surgery
and skin grafts, particularly in the case of cobra
bites.
• Tensed swelling, pale and cold skin with severe
pain may suggest increased intracompartmental
pressure in the affected limb. A clear proof of
significant compartment syndrome by
measurement of substantially elevated
intracompartmental pressures is a prerequisite.
However, fasciotomy is rarely justified. In
particular, it can be disastrous when performed
before coagulation has been restored.
42. prevention
• Many bites could be avoided by educating the population at risk.
Sleeping on a cot (rather than on the floor) and under bed nets
decreases the risk of nocturnal bites.
• Rubbish, termite mounds, and firewood, which attract snakes, can be
removed from the vicinity of human dwellings.
• Attempts can be made to prevent the proliferation of rodents in the
domestic and peridomestic area.
• Thatched roofs, and mud and straw walls are favoured hiding places
for snakes and should be checked frequently.
43. • Using a torch/flashlight while walking on
footpaths at night, and wearing boots and long
trousers during agricultural activities, could
significantly reduce the incidence of bites.
• Snakes are most likely to bite when they feel
threatened, are startled, are provoked, or have
no means of escape when cornered. Leave the
area of a snake is recommended.
• When dealing with direct encounters it is best to
remain silent and motionless. If the snake has
not yet fled it is important to step away slowly
and cautiously.
44. • It is also important to avoid snakes that appear to be dead, as some
species will actually roll over on their backs and stick out their tongue
to fool potential threats. A snake's detached head can immediately
act by reflex and potentially bite. The induced bite can be just as
severe as that of a live snake. Dead snakes are incapable of regulating
the venom they inject, so a bite from a dead snake can often contain
large amounts of venom.
46. • In 2010, an estimated 26,000 people died from
rabies, down from 54,000 in 1990.
• The majority of the deaths occurred in Asia and
Africa.
• India has the highest rate of human rabies in the
world, primarily
- because of stray dogs,whose number has greatly
increased since a 2001 law forbade the killing of
dogs.
- a form of mass hysteria or group delusion known
as puppy pregnancy syndrome (PPS).
• Dog bite victims with PPS (both male and female)
become convinced that puppies are growing inside
them, and often seek help from faith healers rather
than from conventional medical services.
• In cases where the bite was from a rabid dog, this
decision can prove fatal.
47. • Dog bites account for more than 90% of all animal bites.
• Infections, including tetanus and rabies, need to be considered.
• Wound cleaning decreases the risk of infection.
• Skin repair increases the risk of infection, and the decision to suture
the skin balances the risk of infection versus the benefit of a better
appearing scar.
48. • The dog bite victim needs to be taken to a safe
place away from the assailant dog to prevent
further attack and injury.
• Since dog bites can cause significant damage
beneath the skin, a type of injury that cannot
always easily be appreciated, medical care
should be accessed by a health care practitioner.
• Wounds should be kept elevated and, if possible,
washing the wound with tap water may be
attempted.
• Information should be obtained from the dog's
owner about the dog's rabies immunization
status, but if this is not possible, hospital, animal
control centers, or law enforcement personnel
will help gather any required information.
49. • Medical care should be accessed if the dog bite disrupts the skin
causing a puncture, laceration, or tear. As well, if there is pain at or
near the injury site, underlying structures may have been damaged
and medical care may be needed.
• If the skin is not disturbed, or if there is a minimal abrasion present, it
may be reasonable to watch for signs of infection (pain, redness,
warmth, swelling, and drainage of pus or fluid) before seeking
medical care.
50. RABIES
• Rabies ( from Latin: rabies, "madness") is a viral disease that causes
acute inflammation of the brain in humans and other warm-blooded
animals.
• Exposure to a rabid animal does not always result in rabies.
• If treatment is initiated promptly following a rabies exposure, rabies
can be prevented.
• If a rabies exposure is not treated and a person develops clinical signs
of rabies, the diseased almost always results in death.
51. • Early symptoms may include fever and tingling at
the site of exposure.
• This is then followed by either violent movements,
uncontrolled excitement, and fear of water or an
inability to move parts of the body and confusion
followed by loss of consciousness.
• In both cases once symptoms appear it nearly
always results in death.
• The period between infection and the first flu-like
symptoms is typically 2 to 12 weeks.
• Incubation periods as short as four days and longer
than six years have been documented, depending
on the location and severity of the inoculating
wound and the amount of virus introduced .
• The time is dependent on the distance the virus
must travel to reach the central nervous system.
52. • The disease is spread to humans from another
animal, commonly by a bite or scratch. Infected
saliva that comes into contact with any mucous
membrane is also a risk.
• Globally most cases are a result of dog bite.
53. DIAGNOSIS
• Rabies can be difficult to diagnose because, in the early stages, it is
easily confused with other diseases of aggressiveness.
• The reference method for diagnosing rabies is the Fluorescent
Antibody Test (FAT) which is recommended by World Health
Organization (WHO).
• The FAT relies on the ability of a detector molecule (usually
fluorescein isothiocyanate) coupled with a rabies specific antibody
forming a conjugate to bind to and allow the visualization of rabies
antigen using fluorescent microscopy techniques.
54. • The diagnosis can also be made from saliva, urine, and cerebrospinal
fluid samples, but this is not as sensitive and reliable as brain
samples.[
• Cerebral inclusion bodies called Negri bodies are 100% diagnostic for
rabies infection but are found in only about 80% of cases.
• If possible, the animal from which the bite was received should also
be examined for rabies.
55. Differential diagnosis
• Encephalitis, in particular infection with viruses such as
herpesviruses, enteroviruses, and arboviruses( West Nile virus).
• The most important viruses to rule out are herpes simplex virus type
one, varicella zoster virus, and (less commonly) enteroviruses,
including coxsackieviruses, echoviruses, polioviruses, and human
enteroviruses 68-71.
56. treatment
• Almost all human cases of rabies were fatal until
a vaccine was developed in 1885 by Louis
Pasteur and Émile Roux. Their original vaccine
was harvested from infected rabbits, from which
the virus in the nerve tissue was weakened by
allowing it to dry for five to 10 days.
• Treatment after exposure can prevent the
disease if administered promptly, generally
within 10 days of infection.
57. • Thoroughly washing the wound as soon as possible
with soap and water for approximately five minutes
is very effective in reducing the number of viral
particles.
• Patients should receive one dose of human rabies
immunoglobulin (HRIG) and four doses of rabies
vaccine over a 14-day period.The immunoglobulin
dose should not exceed 20 units per kilogram body
weight.
• The rabies vaccine is available as:
- Human diploid cell vaccine (HDCV)
- Purified chick embryo cell vaccine (PCECV)
• The first dose may be given at any time.The second
dose should be given seven days later.The third dose
should be given 21 or 28 days after the
first dose.Booster doses of vaccine are
recommended every two years.
58. • Patients who have previously received pre-
exposure vaccination do not receive the
immunoglobulin, only the postexposure
vaccinations on days 0 and 2.
• As much as possible of this dose should be
infiltrated around the bites, with the remainder
being given by deep intramuscular injection at a
site distant from the vaccination site.
• Intramuscular vaccination should be given into
the deltoid, not gluteal area, which has been
associated with vaccination failure due to
injection into fat rather than muscle.In infants,
the lateral thigh is used as for routine childhood
vaccinations.
59. PREVENTION
• Do not approach a stray or unfamiliar dog,
especially if its owner is not present.
• If a confrontation occurs, do not make eye
contact and do not run or scream.
• Do not approach an unfamiliar dog while it is
eating, sleeping, or caring for puppies.
• Do not leave young children or infants
unsupervised with a dog.
• Contacting an animal control officer upon
observing a wild animal or a stray, especially if
the animal is acting strangely
60. • If bitten by an animal, washing the wound with
soap and water for 10 to 15 minutes and
contacting a healthcare provider to determine if
post-exposure prophylaxis is required
• Vaccinating dogs, cats, rabbits, and ferrets
against rabies
• Keeping pets under supervision
