An acute, highly fatal viral disease of the
central nervous system, caused by
Lyssavirus , Type I.
Also known as Hydrophobia.
20,000 Deaths, 17.4 million animal bite
cases annually.
India accounts for 36% of the Global and
65% of the Asian human rabies deaths.
Agent Factors
Causative Agent : Lyssavirus , Type I
Family- Rhabdoviridae
Bullet shaped
Neurotropic RNA Virus
2 major Ag- G protein & Internal nucleoprotein Ag
G protein- Only Ag capable of inducing the
formation of virus neutralizing Abs.
Street VirusVirus recovered from naturally occurring
cases of rabies
Pathogenic to all mammals & shows a long
incubation period(20-60 days)
Fixed Virus –
Serial brain to brain passage of the street virus
in rabbits modifies the virus such that its
incubation period is progressively reduced until
it becomes constant between 4-6 days.
Used in preparation of anti rabies vaccine
Reservoirs of InfectionUrban Rabies
Wild life Rabies
Bat Rabies
Source of InfectionSaliva of rabid animals
Host Factors
Rabies in man is a dead
end infection
Modes of TransmissionAnimal Bites
Licks
Aerosols
Person to Person
Incubation Period-
Highly variable : from 4 days to many years.
Commonly 3-8 weeks following exposure.
Pathogenesis
Rabies virus replicates in muscle cells and
connective tissue cells at site of injury before
it attaches to the nerve endings & enter
peripheral nerves
Spreads from the site of infection
centripetally via peripheral nerves towards
the CNS.
After that the virus spreads centrifugally
in peripheral nerves to many tissues
including skeletal and myocardial muscle,
adrenal glands, salivary glands and skin.
Salivary gland invasion is crucial for
transmission of the virus to another
animal or human.
CLINICAL FEATURES
Prodromal symptoms
• Headache
• Malaise
• Sore throat
• Slight fever
• Pain or tingling at the site of the bite (80%)
Sensory
• Intolerant to noise and bright light
• Aerophobia
• Dilatation of pupils
• Increase perspiration, salivation and lacrimation
Motor
• Increased reflexes and muscle spasm
Mental Changes
• Fear of death
• Anger
• Irritability
• Depression
HYDROPHOBIA
• Pathognomic of rabies
• Absent in animals
DIAGNOSIS
 On basis of history and characteristic signs
and symptoms
Antigen detection using immunofluorescence
of skin biopsy
 Virus isolation from saliva and other
secretions
TREATMENT – No specific treatment
 Isolate in a quite room protected from external
stimuli
 Relieve anxiety and pain by liberal use of sedatives
 Spastic muscular contractions – use drugs with
curare like action
 Ensure hydration and diuresis
 Intensive therapy in the form of respiratory and
cardiac support
 Precaution of nursing personnel
VACCINEDefined as fluid or dried preparation of
rabies fixed virus grown in the neural tissues
of rabbits, sheep, goats, embryonated duck
eggs , in cell cultures and inactivated by
suitable method.
Louis Pasteur developed the 1st vaccine
(neural tissue) against Rabies in 1885.
 First cell culture vaccine was developed by T J
Wiktor and H Koprowsky in 1965.
TypesNTV : Govt. of India has stopped producing
since 2004
Duck Embryo vaccine
Cell Culture vaccine- Human diploid cell
vaccine and 2nd generation tissue culture
vaccine(PCECV )
Anti Rabies Serum
ERIG
HRIG
Category
I- Touching & feeding of
animals &Licks on intact skin
II- Nibbling of uncovered skin
Minor scratches or abrasions
without bleeding
III- Single/multiple
transdermal bites or scratches
Licks on broken skin.
Contamination of mucosa
memb. with saliva.
Exposure to bats
Type of
exposure
PEP
None
None
Minor
ARV
Severe
ARS
+
ARV
Post Exposure Prophylaxis
Cleansing
Chemical treatment
Suturing
Anti rabies Serum
Antibiotics & anti tetanus measures
Observe the animal for 10 days
Vaccine Administration
Essen Regimen
Intramuscular Schedule
Days: 0,3,7,14,28 and booster on 90.
Dose: 1 or 0.5 ml into deltoid
Thai Red Cross Regimen
2 site intra dermal schedule
(2-2-2-0-1-1)
Days: 0,3 ,7,28,90
Dose(one id dose):1/5th of i/m
dose/site
Updated Thai Red Cross Regimen
The dose to be given on 90th day is
given on 28th day itself.
 8 Site intra demal regimen (8-0-4-0-1-1)
 Deltoid, lateral thigh, supra scapular region, lower
quadrant of abdomen
Pre –Exposure Prophylaxis
Indications-
Laboratory staff working with rabies virus
Veterinarians
Animal Handlers
Wild life exposure
Dose : 1 ml i/m or 0.1 ml i/d on day 0, 7 and
28
Booster doses at intervals of 2 years.
Post–exposure treatment of previously vaccinated
If Ab titre is unknown or bite is severe ,then 3 doses
on day 0,3 and 7.
If titre >0.5 IU/ml and bite is not severe only 2 doses
needed on day 0 and 3
References
Park’s Textbook of Preventive and Social
Medicine, 21st edition
www.apcri.org