As rabies is one of public health important health issue,particularly in developing countries,this slide gives an overview of epidemiology,clinical features and prevention of rabies.

1. Rabies
Melaku Yetbarek(MD,Internist)
November,2023

2. Introduction
• Rabies is one of the oldest known diseases in
history with cases dating back to 4000 years
ago
• Rabies causes viral encephalitis which kills up
to 70,000 people/year worldwide.
• Most of these deaths occur in Asia and Africa,
with rural populations and children
disproportionally affected

3. Epidemiology
• Zoonotic infection
• Transmitted to humans by the bite of an infected
animal
• Worldwide, most human rabies is transmitted
from dogs in countries with endemic canine
rabies and dog-to-dog transmission
• In developed countries, domesticated animals
have only been responsible for about 10% of
cases of rabies transmission

5. Pathogenesis
• Incubation period ranges 20-90 days
• The virus is known to bind to nicotinic
acetylcholine receptors on postsynaptic
membranes at NMJs
• Rabies virus spreads along peripheral nerves
toward the spinal cord or brainstem via
retrograde fast axonal transport

6. Pathogenesis…
• The pathologic changes are surprisingly mild
compared to clinical severity and fatal
outcome of the disease.
• The most characteristic pathologic finding in
rabies is the Negri body
• These inclusion bodies are commonly
observed in Purkinje cells of the cerebellum
and in pyramidal neurons of the hippocampus

8. Clinical features
• Rabies should usually be suspected on the basis
of the clinical presentation with or without a
history of an exposure
• Presents atypical encephalitis with relative
preservation of consciousness
• Phases:
Prodromal,
acute neurologic, and
comatose

9. Clinical…
Prodromal Features:
• Nonspecific manifestations, including
fever, malaise, headache, nausea, and
vomiting.
• The earliest specific neurologic
symptoms of rabies include paresthesias,
pain, or pruritus near the site of the
exposure

10. Clinical…
Encephalitic Rabies:
• May present with fever, confusion,
hallucinations, combativeness, and seizures
• Autonomic dysfunction is common (hyper
salivation, gooseflesh, cardiac arrhythmia, and
priapism)
• Early brainstem involvement(hydrophobia)

12. Clinical…

13. Clinical…
Paralytic Rabies:
• In 20% of patients
• Weakness starts in the bitten leg,
progressively involving to quadriparesis and
facial muscle involvement

14. Clinical…

15. Diagnosis
• Should be considered in patients presenting
with acute atypical encephalitis or acute
flaccid paralysis
• Tests:
Rabies specific antibodies
RT-PCR amplification
Direct Fluorescent Antibody Testing

16. Prevention
Post exposure prophylaxis(PEP):
• local wound care
All bite wounds and scratches should be washed
with soap and water
Remove devitalized tissue
Tetanus prophylaxis
Antibiotics tx(if indicated)
• Active and passive immunization

17. Prevention
• Rabies immune globuline(for previously
unvaccinated persons)
• Rabies vaccines:
 4 doses at 0,3,7 and 14 days
Local reactions (pain, erythema, edema, and
pruritus) and
mild systemic reactions (fever, myalgias,
headache, and nausea) are common

18. Thank you!!!