3. Introduction
• Rabies, also known as hydrophobia, is a
highly fatal viral disease that causes
inflammation of the brain in humans
and other mammals.
• It is a zoonotic viral disease most often
transmitted through the bite of rabid
animals like bats, raccoons, shunks, and
foxes.
• The word “Rabies” originated from
“rabhas” meaning to do violence.
• Louis pasture, a French biologist and
microbiologist was the first person to
diagnose that rabies target the central
nervous system(CNS), and made vaccine
against it.
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4. Rabies is characterized by:
Furious rabies characterized by hyperactivity.
Paralytic rabies characterized by paralysis and coma.
Rabies virus, scientific name Rabie lyssavirus is a
neurotropic virus that cause rabies in all warm blooded
animals.
Bullet shaped virus belonging to rahbdoviridea family.
Member of Lyssavirus genus.
Transmission of virus is through saliva, bites, scratches
and licks of infected animals.
Tens of thousands of people die each year from rabies.
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5. Discovery
• In 1804, Georg Gottfried Zinke proved that rabies
was transmitted in saliva by injecting animals with
saliva from a rabid dog.
• This proved that the disease was infectious. By
1826, Franz Christian Karl Krugelstein (1779–1864)
wrote a full account of rabies, with a bibliography of
300 items.
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6. DISCOVERY
On Monday 6 July 1885, Joseph Meister, aged
nine, was brought to Louis Pasteur from Alsace
having been bitten by a rabid dog on 4 July.
Pasteur inoculated the child with the emulsion
from the cord of rabbit that had died on 21
June because of rabies
The child was given 13 further inoculations in
10 days with portions of the cord that were
progressively fresher (more virulent), until after
three months and three days he announced
that the child's life was now out of danger and
his health appeared excellent.
On 20 October, he successfully treated another
patient infected by a mad dog six days earlier.
By 1886, he had treated 350 patients from all
over Europe, Russia, and America.
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7. • RNA is tightly encased by the
nucleoprotein.
• Outer lipoprotein envelope
carrying knob like spikes are
composed of glycoprotein G.
• Spikes do not cover the planer
end of viron.
Morphology of the virus
• Rabies virus has a bullet-like
shape.
• Rhabdoviruses are approximately
180 nm long and 75 nm wide.
• Genome- Unsegmented, Linear,
Single Stranded RNA, Negative
Sense.
Proteins
• The rabies genome encodes five
proteins; nucleoprotein,
phosphoprotein (P), matrix
protein (M), glycoprotein (G)
and polymerase (L).
• two major structural
components: a helical
ribonucleoprotein core (RNP)
and a surrounding envelope.
Envelope
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Shape and Genome
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Glycoprotein (G)
Matrix protein (M)
Nucleoprotein (N)
Phosphoprotein
Polymerase (L)
• The phosphoprotein and the large
protein (L-protein or polymerase) are
associated with the RNP.
• Beneath envelope is the membrane or
Matrix (M) protein layer which may be
invaginated at the planer end.
• Membrane may project outwards from
the planer end
• Core of viron contains helically
arranged nucleoprotein.
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•The period between the bite and the onset of symptoms is called the incubation period.
•Don’t have any symptoms during this time. You won't get rabies if you obtain treatment early
in the incubation phase.
Incubation phase
•Starts when the rabies virus has entered the nervous system. Immune system tries to fight
back, causing flu-like symptoms.
•Nerve damage might cause tingling, pain or numbness where the individual has been bitten.
•There aren’t any effective treatments when rabies reaches this phase.
Prodromal phase
•Virus starts damaging the brain and spinal cord. About two-thirds of people have furious
rabies while others have paralytic rabies.
•Furious rabies can last a few days to a week. Paralytic rabies can last up to a month.
Neurologic phase
•Many people enter a coma in the final stages of the infection.
•Major cause of death is respiratory paralysis.
Coma and death
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Mode of transmission & Pathogenesis
• By the bite of the rabid animal (dog, cat,
fox, raccoons).
• The contamination of scratch wound by
virus infected saliva
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13. Adsorption and Penetration
Transcription/Translation
Assembly and Budding
13
Replication
o During attachment, the
interaction of G-proteins and
specific cell receptors such as
acetylcholine receptors,
phosphatidyl serine receptors
may be involved.
o The virus penetrates the host
cell and enters cytoplasm, where
it fuses with endosomes, causing
the release of the viral genome
into cytoplasm.
o The negative-sense ssRNA genome
is transcribed into positive-sense
mRNA by RNA polymerase.
o These mRNAs code for the five
virion proteins: Nucleocapsid
protein (N), Polymerase proteins
(L,P), Matrix protein (M), and
Glycoprotein (G).
o Although, G protein synthesis is
initiated on ribosomes, completion
of synthesis and
glycosylation(processing of
glycoprotein) occurs in Endoplasmic
reticulum and Golgi apparatus.
o The genome RNP
(ribonucleoprotein) is a
template for complementary
positive-sense RNA, which is
responsible for the generation
of the negative-sense RNA
progeny.
o During assembly process, the
N-P-L complex encapsulates the
–ive stranded genomic RNA to
form RNA core, and M protein
forms the capsule or matrix
around RNP.
o The M-RNP complex binds the
glycoprotein, and the
completed virus buds off from
the plasma membrane.
15. Symptoms
Fever
Tiredness (fatigue)
Cough
Muscle pain
Sore throat
Tingling, pain or numbness.
Usually humans have no symptoms of rabies for several weeks after it enters the
body.
When virus enters the central nervous system (prodromal phase), human
experience flu-like symptoms.
In final stages, humans have neurological (brain) symptoms.
Prodromal symptoms of rabies
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Neurological symptoms of rabies are either furious or paralytic.
Furious rabies symptoms
Furious rabies symptoms may come and go with periods of calm in between (furious episodes).
Neurologic symptoms of rabies
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Hallucinations
Aerophobia
Hydrophobia
Facial paralysis
Seizures
Hyperventilation
Delirium
Restlessness
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Rabies vaccine: Your healthcare
provider will give you four shots over
14 days. If you’ve already been
vaccinated before exposure, you’ll
only need two shots. The vaccine
teaches your body to destroy the
rabies virus before it enters your
brain.
Human rabies immune globulin
(HRIG): Your provider will give you
shots around the wound. HRIG gives
you antibodies (molecules that fight
infection) that will destroy the virus
near the wound until your body takes
over. You shouldn’t get HRIG if you’ve
been vaccinated before your
exposure.
Your provider will give you a series of
shots (vaccinations) to prevent the
virus from causing rabies. They’ll also
give you an antibody treatment
directly to the wound if you’ve never
been vaccinated before.
If you’re bitten or scratched by a wild
animal, there are steps you can take
to prevent rabies.
Treatment of Rabies
• There’s no approved treatment for
rabies once you have symptoms.
• If you’ve been exposed to rabies,
contact a healthcare provider as soon
as possible.
• Clean the wound gently but thoroughly
with soap and water. Ask your provider
for additional instructions on cleaning
the wound.
19. Side effects of rabiestreatment
You might have mild side effects from rabies vaccines, including:
• Pain, itching, or swelling where you received the shots
• Nausea
• Headache
• Muscle pain
• Dizziness
If you have severe side effects, contact your provider.
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Editor's Notes
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