Back to Basics: Rabies


  • viral disease caused by lyssaviruses

  • transmission occurs when infected animal scratches or bites another animal or human

  • globally over ninety percent of transmission is due to dogs; however in the US and other countries with canine control wild animals account for most cases (raccoons, skunks, bats, foxes, etc,)

  • bat exposure without a documented bite may require rabies prophylaxis - ex: awakening in a room with a bat

  • known dogs or cats should be observed for 10 days

  • animals almost never found to be rabid include squirrels, chipmunks, rats, mice, and rabbits



  • incubation period : 20 - 90 days

  • initial symptoms : fever, malaise, headache, anorexia, nausea, pain / paresthesia at bite site

  • later symptoms : restlessness, agitation, muscle spasms, hydrophobia, opisthotonos, motor paresis, altered mental status



  • diagnosed clinically - no laboratory test

  • confirmatory diagnoses made by postmortem brain tissue studies



  • initial assessment should focus on true risk for rabies, notification of public health / animal control, and administration of postexposure prophylaxis

  • local wound care VIP

  • human rabies immune globulin (HRIG) - administered once after exposure, 20 IU/kg (1/2 locally at exposure site, 1/2 intramuscularly)

  • human diploid cell vaccine (HDCV) - administered intramuscularly on days 0, 3, 7, and 14




Tintinalli, JE. Tintinalli's Emergency Medicine: A Comprehensive Study Guide. 8th ed. New York, NY: McGraw-Hill Education LLC, 2016.