Animal bites and stings

1. Animal Bites And Stings
Dr Massam
1

2. Objectives
At the end of this session, students are expected
to be able to:
Part 1
• Define animal bites
• Identify cause
• Describe pathophysiology
• Describe clinical features
• Manage animal bites
2

3. Objectives
Part 2
• Define insect bites and stings
• Identify cause
• Describe clinical features
• Manage animal bites and stings

4. Animal bites

5. Introduction
• Animal bites
–Animal bites are wounds inflicted on the
body due to animals sinking teeth into one’s
body.
–Animal bites and scratches, even when they
are minor can become infected and spread
bacteria to other parts of the body.

6. Introduction cont..
• Whether the bite is from a family pet or an
animal in the wild, scratches and bites can
carry disease.
• Some animals can transmit rabies and tetanus.

7. Causes
• Human bites
• Snake bite
• Alligator & crocodile bite
• Domestic animals like dogs and cats
• Skunks, raccoons, bats, foxes, and most other
caranivores; woodchucks
• Livestock, rodents, and lagomorphs (rabbits
and hares)

8. Pathophysiology
• Human bites
–Human bites can be as dangerous as or even
more dangerous than animal bites because
of the types of bacteria and viruses
contained in the human mouth
–A common human bite wound associated
with high morbidity is either fight bite or
teeth bites

9. Pathophysiology cont..
• Snakebites and Venom
–Poisonous snakes inject venom using
modified salivary glands
–Venomous snakes of medical importance
have a pair of enlarged teeth, the fangs, at
the front of their upper jaw.

10. Pathophysiology cont..
–If a human is bitten, venom is usually
injected subcutaneously or intramuscularly.
–Spitting cobras can squeeze the venom out
of the tips of their fangs, producing a fine
spray directed toward the eyes of an
aggressor

11. Pathophysiology cont..
• Examples of venom toxins
–Black Mamba has neurotoxic venom and
cardio-toxic venom
–The Puff Adder has cyto-toxics venom
–Boomslang snake and carpet Viper both
have hemotoxic venom

12. Clinical features of snake bites
• Eyes (spitting cobras and ringhals can eject
their venom quite accurately into the eyes of
the victims, resulting in direct eye pain and
damage)
• Swelling and tissue damage
• Suddenly develop breathing difficulty and go
into shock

13. Clinical features of snake bites cont..
• Local effects (swollen, bleeding, blister and
gangrene)
• Nervous system effects (vision problems,
speaking and breathing trouble, and numbness
close to or distant to the bite site, and death
without treatment)
• Muscle death (muscle necrosis,
rhabdomyolysis, kidney failure)

14. Snake bite treatment
Non pharmacological
• Application of a tourniquet, incision and
suction are appropriate if done within one hour
from time of bite
• Elevate limb if swollen
• Paralysis of respiratory muscles may requires:-
–Intubation and mechanical ventilation or
manual ventilation

15. Snake bite treatment cont..
Pharmacological
• If there are systemic signs or severe local signs
(swelling of more than half of the limb or severe
necrosis), give antivenom (crotalidae polyvalent
immune)
– The dose of anti-venom serum required depends on
the amount of venom injected by the snake,
– The initial doze should be large; at least contents of
20 ml, but the condition of the patient may demand
the injection of up to 4 or 5 times as much

16. Snake bite treatment cont..
• Also give Epinephrine (adrenalin), IM dose of
1:1000 (Repeat after 5 min if no improvement)
–Children > 12 years and Adults
500microgram (0.5ml)
–Children 6-12 years 300microgram (0.3ml)
–Children < 6 years 150 microgram IM
(0.15ml)

17. Snake bite treatment cont..
AND
• IV Chlorpheniramine and be ready if allergic
reaction occurs. Dosage as below
–Children under 6 years: 4mg 8hourly needed
–6-12 years: 8mg (PO) 12 hours as needed
–>12 years and older 12mg 12hourly needed

18. Snake bite treatment cont..
• If in shock, give normal Saline 10-20mls/kg
bolus, repeat after 30min if still in shock
• Vitamin K may be required to correct bleeding
and clotting abnormalities
• Tetanus toxoid administered and antibiotics
recommended to prevent secondary infection

19. Snake bite treatment cont..
Surgical Intervention
• Excision of dead tissue from wound
• Incision of facial membranes to relieve
pressure in limb compartments, if necessary
• Skin grafting, if extensive necrosis
• Tracheotomy if paralysis of muscles involved
in swallowing occurs

20. Treatment cont..
For Dogs and cats bites
• When the dogs or/and cats are available and
proven that they are health
–Treatment should include:-
• The victim should not begin prophylaxis
• And 10 days observation, unless animal
develops symptoms of rabies

21. Treatment cont..
• Rabid or suspected rabid (Dogs and cats bites)
–Treatment should include:-
• Immediate vaccination
• consider also tetanus toxoids
• Unknown (escaped) (Dogs and cats bites)
–Treatment should includes:-
• Consult public health officials

22. Treatment cont..
• Skunks, raccoons, bats, foxes, and most
other caranivores; woodchucks bites
–Regarded as rabid unless geographic area is
known to be free of rabies or until animal
proven negative by laboratory tests
–Treatment should includes:-
• Immediate vaccination

23. Treatment cont..
• Livestock, rodents, and lagomorphs (rabbits
and hares)
–Consider individually
– Treatment should includes:-
• Consult public health officials;
• bites of squirrels, hamsters, guinea pigs,
gerbils, chipmunks, rats, mice, other
rodents, rabbits, and hares almost never
require anti-rabies treatment

24. Insect bites and stings

25. Introduction
• A sting is usually from an attack by a
venomous insect such as a bee or wasp, which
uses this as a defense mechanism by injecting
toxic and painful venom through its stinger.
• Insect bites and stings can be divided into 2
groups namely: venomous and nonvenomous.
• Non-venomous insect bites pierce the skin to
feed on blood, this usually results in intense
itching.

26. Causes
• Venomous (stingers)
–Fire ants
–Yellow jackets
–Hornets
–Wasps
–Bees

27. Causes cont..
• Non-venomous (biters)
–Bed bugs
–Fleas
–Ticks
–Lice
–Scabies
–Caterpillars and moths
–Mosquitoes

28. Clinical features
• Localized pain
• Petechial hemorrhages
• Swelling of skin and mucus membrane
• Generalized erythema
• Abdominal cramps
• Pulmonary and cerebral edema
• Blurred vision

29. Clinical features cont..
• Vascular collapse
• Death results from combination of shock
• Respiratory failure and CNS changes
• Most death from insect stings occur within 15
to 30 minutes
• Early application of a tourniquet may prevent
rapid spread of venom
• Emergency kit containing epinephrine
commercially available

30. Treatment
Non-Pharmacological
• Clean the area with soap and water to remove
contaminated particles left behind by some
insects
• Refrain from scratching because this may
cause the skin to break down and results to an
infection

31. Treatment cont..
• Pharmacological treatment
–Ibuprofen: 400-800mg orally 8 hourly for 3
days
–Prednisolone: 2 mg/kg/day (PO) in single
daily not to exceed 80 mg/day for 5 days
–Where there is an anaphylactic reaction treat
according to guideline.

32. Treatment cont..
–Diphenhydramine: 50 mg orally 6 hourly
not exceeding 300mg/day for 5days. In
severe reaction 50mg IV 6 hourly not
exceed 400mg/day for 5 days
–Cimetidine/Ranitidine: 5-10 mg/kg IV
6hourly for 5days

33. Key points
• Animal bites and scratches, even when they
are minor can become infected and spread
bacteria to other parts of the body.
• Domestic animals like dogs and cats are the
most frequents reported animal bites
• Treatment of animal bites includes surgical
debridement and detoxification with
antivenom

34. Key points
• An insect sting is usually from an attack by a
venomous insect such as a bee or wasp, which
uses this as a defense mechanism by injecting
toxic and painful venom through its stinger.
• The insect that is responsible for the majority of
serious sting related reactions include bees,
wasps, spiders, scorpions, ants and centipedes.
• Non-venomous insect bites pierce the skin to feed
on blood, this usually results in intense itching.

35. Review questions
1. What is an animal bite?
2. Mention cause of animal bites and stings?
3.Describe management of snake bites?

36. References
• MoHCDGEC (2017). Standard Treatment
Guidelines and National Essential Medicines
List: Tanzania Mainland (4th Ed).