Rabies

Worldwide: Responsible for 59,000 deaths worldwide per year (95% in Asia and Africa)
1. Children under age 15 years account for 40% of cases
U.S.
1. Typically 1-3 Rabies (up to 8-10 in some years) cases in U.S. per year
2. Most cases of Rabies are from exposure to wild animals in U.S. (90%)
3. Up to 8000/year in U.S. of documented cases of Rabies in animals
  1. The most common reported domestic Rabies cases are in cats
  2. Although rodents and rabbits can carry Rabies, no human cases have been attributed to these animals

Lyssavirus Infection
1. Rhabdoviridae Family (RNA Viruses)
2. Zoonotic neurotropic virus
Transmitted by bite or scratch from infected mammals
1. Saliva, brain and other nerve tissue are infectious
2. Blood, urine, and stool are not infectious
3. Mucosal contact with bats may also transmit Rabies (unique to bats)
Course
1. Incubation Period is 4-12 weeks
Highest risk animals
1. Bats
  1. See Bat Bite
  2. Responsible for most U.S. cases of Rabies (87% of cases 1980-2015)
  3. Even indirect exposure (no bite) may indicate prophylaxis
2. Dogs
  1. See Dog Bite
  2. Worldwide, these are main vector for infection
  3. However, in U.S. Rabies is less common in dogs (70 cases/year in U.S.)
    1. Responsible for 11 of 31 U.S. human Rabies cases 2003-2016
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
  1. Most common vector in the U.S. East Coast
5. Skunks
  1. Most common vector in the U.S. midwest and West Coast
6. Foxes
  1. Gray fox is the most common vector in the U.S. southwest
7. Coyotes
8. Bobcats
9. Woodchucks
10. Ferrets

Travel to endemic regions (africa, Asia, Eastern Europe), esp. rural or wilderness areas
Extremes of age (young children, elderly)
Bites or scratches from infected animals (esp. bats, raccoons, skunks, foxes, dogs)
1. Unprovoked bites (aggressive animals)
2. Bite proximity to the brain increases risk
Occupational exposure risks
1. Veterinary field, animal handlers or wildlife biologists
2. Related laboratory workers)

Incubation Period: Days to months
Early (Prodromal)
1. Local radiating Paresthesia from bite site
2. Malaise
3. Nausea
4. Pharyngitis
Late (Neurologic)
1. Restlessness
2. Significant Agitation
3. Hallucinations
4. Bizarre behavior or personality change
5. Seizures
6. Aerophobia and Hydrophobia are pathognomonic

Early
1. Wound Inflammation
2. Hyperesthesia at wound site
Late (Encephalitis)
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)
Terminal signs
1. Flaccid Paralysis
2. Hospitalization <1 week after symptom onset
3. Coma within one week of encephalopathy signs
4. Death

Live Observation of suspected infected mammal
Rabies Virus Antigen Testing
1. Saliva contains virus
2. Brain and spinal cord of suspected infected animal

See Rabies Postexposure Prophylaxis
See Dog Bite
General wound care (in addition to Rabies Prophylaxis)
1. Clean wounds with copious irrigation including antiseptics (e.g. Chlorhexidine)

Rabies Vaccine
1. For Rabies Postexposure Prophylaxis and preexposure prophylaxis
Rabies Immunoglobulin
1. Rabies Postexposure Prophylaxis
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)
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
Test for Rabies in pets who succumb to illness quickly