Dog bites can cause serious wounds and infections. Large dog breeds are more likely to bite the head and neck, causing deep tissue damage. Children aged 5-14 are most commonly bitten. Bites may be provoked by antagonizing or hurting an animal, or unprovoked by approaching young animals, food, or territorial animals. Wounds require cleaning, suturing if appropriate, antibiotics, and tetanus prophylaxis. For exposures, rabies post-exposure prophylaxis including vaccine and possibly immune globulin is administered based on category of exposure. The rabies virus causes encephalitis with a nearly 100% fatality rate if left untreated.

1. Dog Bites

2. Dogs
• Prominent canine teeth
• Enormous pressure when biting
• Large breeds tend to cause
wounds in the head and neck
• Powerful jaws can penetrate the skull and
destroy deep tissue

3. Victims
• Males are more likely to be bitten by dogs.
• Females are more likely to be bitten by
cats.
• Animal bites are most common in children
aged 5-14 years

4. Cause
• Causes of provoked attacks
– Antagonizing an animal
– Hurting an animal
• Causes of unprovoked attacks
– Approaching the young of an animal
– Approaching an animal that is eating
– Entering the property of a territorial animal
– Nearing an animal with rabies

5. Mortality/Morbidity
• Wound infection and cellulitis
– Puncture wounds have a higher rate
of infection than lacerations
– Lacerations cause more damage to tissues
than puncture wounds
– Septic arthritis from wounds in joint spaces
• Osteomyelitis from deep wounds
• Meningitis from penetrating skull wounds
• Rabies

6. Exams and Tests
• Inspection the wound
• X-rays to look for fractures or foreign body
in the wound.

7. Rabies contacted Category
Category Contact
touching or feeding suspect animals,
Category I
but skin is intact
minor scratches without bleeding
Category II
from contact, or licks on broken skin
one or more bites, scratches, licks
on
Category III
broken skin, or other contact that
breaks the skin; or exposure to bats

8. Treatment
• Wound care
– Irrigation and Debridement
• Suture:
– Primary closure in facial wounds
( rarely infected because of well vascularized)
– Delayed closure
• heavily contaminated (dirty)
• significant amount of tissue damage
• hands or lower extremities or
• wound older than 6 hours
– Some wounds are never sutured

9. Medical treatment
• Antibiotic coverage for
– staphylococci
– anaerobes
• Tetanus prophylaxis
• Rabies prophylaxis

10. Antibiotics commonly used
• Amoxicillin clavulanate (Augmentin ®)
• Ampicillin-sulbactam (Unasyn ®)
• Trimethoprim and sulfamethoxazole (Bactrim ® )
• Clindamycin (Cleocin ®)
• Erythromycin (E-Mycin, Ery-Tab, Erythrocin)
• Ceftriaxone (Rocephin ®)
• Tetracycline (Sumycin ®)

11. Vaccines and immune globulins
• Tetanus toxoid
• Rabies vaccine
• Rabies immune globulin

12. Tetanus vaccine
Intramuscular injection
Dose 1 Dose 2 Dose 3
Day 0 Month 1-2 Month 6-12

13. Tetanus prophylaxis consideration
CLEAN
ALL OTHER
IMMUNIZATION HISTORY MINOR
WOUNDS
WOUND
1. Fewer than 3 doses; or TT only TT +
2. Uncertain number of doses; or TIG*
3. No immunization
At least 3 previous doses of tetanus vaccine, TT only TT only
but the most recent more than 10 years ago
At least 3 previous doses of tetanus vaccine, no TT only
but the most recent more than 5 and less than immunization
10 years ago required
At least 3 doses of tetanus, with the most no no
recent 5 years ago or less immunization immunization
required required
TIG*= Tetanus Immune Globolin
http://www.health.gov.nl.ca/health/publications/immunization/S5/tetanus_prophylaxis_in_wound_man.htm

14. Rabies vaccine
• Protection level should be achieved by day 14 of
a post-exposure immunization regimen, with or
without simultaneous administration of RIG and
irrespective of age.

15. Vaccine & RIG consideration
Category Contact Immunization
touching or feeding suspect animals,
Category I None
but skin is intact
minor scratches without bleeding
Category II Vaccine
from contact, or licks on broken skin
one or more bites, scratches, licks on
Category III broken skin, or other contact that Vaccine + RIG
breaks the skin; or exposure to bats

16. Post-exposure rabies vaccination
schedule
Day
dose 0 3 7 14 30 90
Regimen
5 dose IM 0.5 1 1 1 1 1
4 dose IM 0.5 2 0 1 0 1
(21)
8 site ID 0.1 8 0 4 0 1 1
2 site ID 0.1 2 2 2 0 1 1

17. 8 sites Intradermal administration
Day 0 7 30 90
Day 0 7
Day 0
Day 0
Day 0 7
07/17/09 17

18. Rabies immunoglobulin
• Passive antibody is present 24 hours after injection
• Half-life of approximately 21 days.
• Dosage
– HRIG 20 IU/kg
– ERIG 40 IU/kg,
admin as soon as possible at the same time as vaccine, or up to 7
days after vaccine inj.
HRIG 300 IU/2ml ~ 4000 baht ERIG 1000IU/5ml~ 1900 baht
(1 vial / 15 kg BW) (1 vial / 25 kg BW)

19. Should not inject RIG
• Later than 7 days after the initiation of
post-exposure vaccination.
• Previously immunized
as this may reduce the immunologic response
to the vaccine.

20. Precuation
• RIG may interfere with the body's immune
response to certain live virus vaccines such as
measles, mumps, and rubella, should be
administered at least 14 days prior to, or at least
3 months after administration of RIG
• If IM inj is contra-indicated, inj may be given by
SC with pressure and compress applied to site
after inj.
• Do not exceed recommended doses as this may
reduce the immune response to rabies vaccine.

21. Previously immunized person
• 2 IM / ID doses
– Day 0 and day 3
• RIG should not be given.
Full PEP should be given to persons :
– who received pre-or post-exposure prophylaxis with
vaccines of unproven potency
– patients whom immunological memory is not longer
assured as a result of HIV/AIDS or other immunosupp
ressive causes

22. OPD or IPD

27. I am a
Pit bull

28. Another pit bull attack

30. Rabies
• A viral, zoonotic
neroinvasive disease
• Mortality rate of 100%
35,000-50,000 deaths
annually worldwide

33. Transmission
• Humans most often become infected with rabies through
the bite or scratch of an infected dog or cat.
• Routes of transmission have been documented and
include contamination of mucous membranes (i.e., eyes,
nose, mouth), aerosol transmission, and corneal
transplantations
• Rabies virus can be excreted in the saliva of infected
animals several days before illness is apparent

34. • Figure 2. The cycle of rabies infection begins with viral entry at a peripheral site and
proceeds through retrograde axonal transport. Viral replication occurs in the cell body
of the primary neuron. Infection proceeds by transsynaptic spread through several
neurons before spreading to the acinar cells, which then shed the virus into the saliva
(Dietzschold et al. 2005).

37. Rabies virus
• Rabies virus travels along axons at a rate of
12-24 mm/d* to enter the spinal ganglion
• From here, the rabies virus spreads quickly, at a
rate of 200-400 mm/d* into the CNS
• Average incubation is 20-90 days.
– > 90% of cases, incubation is less than 1 year
– Rarely, incubation lasts as long as 19 years.
*http://emedicine.medscape.com

38. Test for rabies
• Rabies diagnosis in animals(after the animal is dead).
– Direct Fluorescent Antibody (DFA) is the “gold standard” diagnostic method for
rabies
– Tissue from at least two locations in the brain, preferably the brain stem and
cerebellum.
• Rabies diagnosis in humans
– Tests are performed on samples of saliva, serum, spinal fluid.
– Skin biopsy specimens are examined for rabies antigen in the
cutaneous nerves at the base of hair follicles
• Rabies virus is not found in blood, urine, or feces.

39. Incubation period ( 20-90 day)
asymptomatic Symptoms
Prodromal period (enters the CNS, 2-10 day)
fever malaise anorexia headaches
nausea emesis
oagitation diarrhea
Neurologic period (objective signs of
developing CNS disease , 2-7 days)
psychosis, restlessness ,seizures, aphasia
hydrophobia and aerophobia
signs of cranial nerve involvement: diplopia
facial palsy, and optic neuritis
Coma and death