- Department of Community Medicine ACME Pariyaram
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Transcript - Department of Community Medicine ACME Pariyaram
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 VirusVirus 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 InfectionUrban Rabies
Wild life Rabies
Bat Rabies
Source of InfectionSaliva of rabid animals
Host Factors
Rabies in man is a dead
end infection
Modes of TransmissionAnimal 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
VACCINEDefined 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.
TypesNTV : 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