Bite, Animal



  • Animal bites are common and account for ∼1% of ED visits
  • Most bites are from provoked animals
  • Dog-bite wounds:
    • Large dogs inflict the most serious wounds (pit bulls cause the most human fatalities)
    • Most fatalities in children (70%) due to bites to face/neck
    • Dogs of family or friends account for most bites
  • Cat-bite wounds:
    • Majority from pets known to victim
    • 50% infection rate in those seeking care
    • Puncture wounds most frequent due to sharp, thin teeth causing deep inoculation of bacteria
  • Cat scratch disease (CSD):
    • 3 of the following 4 criteria:
      • Cat contact, with presence of scratch or inoculation lesion of the skin, eye, or mucous membrane
      • Positive CSD skin test result
      • Characteristic lymph node histopathology
      • Negative results of lab studies for other causes of lymphadenopathy
  • Rat-bite wounds:
    • Occur in lab personnel or children of low socioeconomic status
    • Rat-bite fever (RBF), rare in the U.S. but high mortality rate
    • Rat bites rarely transmit rabies, and prophylaxis not routine unless animal is suspected to be rabid


  • Dog and cat bites:
    • Pasteurella multocida is the major organism in both:
      • Twice as likely to be found in cat bites than dog bites
      • Gram-negative aerobe found in up to 80% of cat infections
      • Infection appears in <24 hr
    • Staphylococcus or Streptococcus:
      • Infection appears in >24 hr
    • Other organisms include anaerobes and Capnocytophaga canimorsus (dogs)
  • CSD:
    • Caused by Bartonella henselae
  • Rat bites:
    • Caused by Spirillum minus and Streptobacillus moniliformis (RBF)

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