Snapshot A 13-year-old boy in rural Asia presents to a local hospital after a dog bite. The dog did not belong to anybody and is often seen running around the area. His parents report that this occurred a few weeks ago, but that they weren’t concerned until the boy started having low-grade fever and chills. While the physician explains that they can administer both active and passive immunity, as symptoms have already started, the parents must prepare for the worst. Introduction Classification rabies virus a negative single-stranded linear RNA virus a rhabdovirus a helical capsid and bullet-shaped transmission via bites from infected animals developed countries bats > raccoons, and skunks > dogs developing countries dogs > others via aerosol transmission (rare) bats Associated conditions encephalitic rabies (more common) paralytic rabies Prevention whole virus inactivated vaccine passive immunization rabies immunoglobulin active immunization Epidemiology Demographics more common in children majority of cases are in Asia and Africa Risk factors interaction with non-domestic animals ETIOLOGY Pathogenesis long incubation period (weeks to months) replicates in muscle and binds to the nicotinic acetylcholine receptor retrograde migration to central nervous system via dynein motors Presentation Symptoms nonspecific prodrome malaise fever headache Physical exam fever encephalitic rabies hydrophobia muscle spasms when offered water leads to “foaming at the mouth” photophobia autonomic dysfunction excess sweating piloerection hypersalivation agitation seizures paralytic rabies quadriparesis bilateral facial weakness late stage disease paralysis coma death Studies Labs viral studies reverse transcription and polymerase chain reaction isolation of virus Histology brain biopsy performed post-mortem negri bodies eosinophilic inclusion bodies in cerebellar Purkinje cells and hippocampal neurons pathognomonic Making the diagnosis based on clinical presentation Differential Botulism distinguishing factor flaccid paralysis without other signs of encephalopathy Temporal lobe (herpes simplex virus-1) encephalitis distinguishing factor disinhibited behaviors such as hyperphagia, hypersexuality, and hyperorality Treatment Management approach give post-exposure prophylaxis immediately when bitten by rabid animal when bite cannot be ruled out if the animal is domestic observe the animal for 24-48 hours once patients are symptomatic, there is no treatment and patients should receive supportive care pain management sedation Conservative wound cleaning indication post-exposure Medical post-exposure prophylaxis indication first-line treatment given immediately after potential high-risk exposure and unable to observe animal drug regimen rabies vaccine alone patients who have received a rabies vaccine series in the past rabies vaccine plus rabies immune globulin patients who have not received a rabies vaccine series in the past Complications Respiratory failure leading to death Prognosis Most cases, without early intervention, lead to coma and death within weeks