Rabies

Description

Viral infection transmitted by mammals that causes CNS dysfunction:

• Highest case fatality rate of any known infectious disease
• Nearly 100% fatal

Etiology

• Epidemiology:
  • The US has only 2–3 human cases per year
  • Most clinical cases in the US from bat exposure and foreign travel
  • In the US, bats are the most common reservoir (30.9%), followed by raccoons (29.4%), skunks (24.8%), foxes (5.9%), cats (4.4%), cattle (1.5%), and dogs (1.2%)
  • ∼59,000 people die/yr of canine rabies worldwide
  • Especially common in Southeast Asia, Philippines, Africa, South America, and Indian subcontinent
  • Worldwide, dog bites are most common vector
  • Squirrels, rats, mice, hamsters, guinea pigs, gerbils, chipmunks, and rabbits can also be infected, but there has never been a reported case of human transmission
  • Rarely rabies cases have been reported in transplant patients
• Pathophysiology:
  • Negative-stranded RNA virus, family Rhabdoviridae, genus Lyssavirus
  • Progression of infection:
    • Virus multiplies in local tissue
    • Virus enters peripheral nerves and travels to the CNS
    • Once in the CNS, rapid replication and dissemination causes neuronal dysfunction
    • The virus then spreads back out along peripheral nerves to salivary glands, skin, cornea, and other organs