Virus

Rabies

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Rabies

  • Epidemiology
  1. Worldwide: Responsible for 59,000 deaths worldwide per year
    1. Children under age 15 years account for 40% of cases
  2. U.S.
    1. Eight human cases of Rabies per year
    2. Up to 8000/year in U.S. of documented cases of Rabies in animals
  • Pathophysiology
  1. Transmitted by bite of infected mammals
    1. Saliva, brain and other nerve tissue are infectious
    2. Blood, urine, and stool are not infectious
  2. Highest risk animals
    1. Bats
      1. See Bat Bite
      2. Responsible for most U.S. cases of Rabies (87% of cases 1980-2015)
    2. Dogs
      1. See Dog Bite
      2. Worldwide, these are main vector for infection
      3. Responsible for 11 of 31 U.S. human Rabies cases 2003-2016
      4. Rabies is less common in dogs (70 cases/year in U.S.)
    3. Cats
      1. See Cat Bite
      2. Most common domesticated animal with Rabies in U.S. (257 cases of cats with Rabies in 2012)
    4. Raccoons
    5. Skunks
    6. Foxes
    7. Coyotes
    8. Bobcats
    9. Woodchucks
    10. Ferrets
  • Symptoms
  1. Early
    1. Local radiating Paresthesia from bite site
    2. Malaise
    3. Nausea
    4. Pharyngitis
  2. Late
    1. Restlessness
    2. Hallucinations
    3. Aerophobia and hydrophobia are pathognomonic
  • Signs
  1. Early
    1. Wound Inflammation
    2. Hyperesthesia at wound site
  2. Late
    1. Dysarthria
    2. Hoarseness
    3. Aphonia
    4. Dysphagia for fluids
    5. Shallow or irregular breathing
    6. Seizure
    7. Delirium
    8. Opisthotonos stimulated by lights or noises
    9. Hyperactive Deep Tendon Reflexes
    10. Nuchal Rigidity
    11. Abnormal Babinski reflex (Up-going toes)
  3. Terminal signs
    1. Flaccid Paralysis
    2. Hospitalization <1 week after symptom onset
    3. Coma within one week of encephalopathy signs
    4. Death
  • Labs
  1. Saliva
    1. Contains virus
  2. Microscopic exam
    1. Brain and spinal cord of suspected infected animal
  3. Live Observation of suspected infected mammal
  • Management
  1. See Rabies Prophylaxis
  2. See Dog Bite
  • Prevention
  1. Rabies Vaccine
  2. Avoid bat exposure
    1. Remove bat roosts from home
    2. Bats trapped within a home living space are more likely to be sick (disabled navigation)
  3. Pets should be vaccinated against Rabies
    1. In U.S., of pets causing a bite evaluated in ER, only 45% of dogs and 8% of cats were vaccinated against Rabies
  4. Test for Rabies in pets who succumb to illness quickly
  • References
  1. Swaminathan and Hope in Herbert (2018) EM:Rap 18(12): 11-2
  2. Messenger (2002) Clin Infect Dis 35:738-47 [PubMed]
  3. Wilde (2003) Clin Infect Dis 37:96-100 [PubMed]