Rabies

Pathogen

  • Virus; zoonosis

Transmission/epidemiology

  • 60,000 deaths/yr, almost 1/3 in India

  • Mammal bites/saliva-contaminated scratches (mainly domestic dogs)

Clinical features

  • Incubation 4 days to several years (usually a few months)

  • Virus spreads from wound along nerve axons to reach CNS causing fatal encephalitis (death in 1-7 days)

  • Furious (more common): hyperactivity, confusion, hallucinations, hydrophobia

  • Paralytic: drowsiness, flaccid paralysis, pain, fasciculations

  • Autonomic hyperactivity e.g. hypersalivation, lacrimation, BP, cardiorepsiratory arrest

Diagnosis

  • PCR (saliva/skin biopsy), virus isolation (saliva, brain, CSF), immunofluorescence of viral antigen (skin punch biopsies). Neutralising antibody response absent/delayed

Treatment

  • Palliative

  • Milwaukee protocol (cocktail of antiviral, intensive care) ? Only for early encephalitis with American bat rabies

Prevention

  • Dog vaccination

Post-exposure Prophylaxis (PEP)

  • Clean wound + anti-tetanus toxoid +/- antibiotics

  • Vaccine. Standard 5-dose IM method days 0, 3, 7, 14, 28 ( days 0 and 3 if had vaccine pre-exposure)

Category 1

  • None

Category 2

  • Minor

Category 3

  • Severe

  • Rabies immunoglobulin into wounds for major exposure

Pre-Exposure rabies vaccination

  • Days 0, 7, 28