Rabies Virus - Dr. S. Sivasankara Narayani

1. 17CY312 – MEDICAL
MICROBIOLOGY (UNIT –II)
Dr. S. SIVASANKARA NARAYANI
ASSISTANT PROFESSOR
DEPARTMENT OF MICROBIOLOGY
AYYA NADAR JANAKI AMMAL COLLEGE
SIVAKASI
05-09-2020Dr.SS
Rabies Virus

2. INTRO
• Rabies is a preventable viral disease most often transmitted through the bite of a
rabid animal.
• The rabies virus infects the central nervous system of mammals, ultimately
causing disease in the brain and death.
• The vast majority of rabies cases reported to the Centers for Disease Control and
Prevention (CDC) each year occur in wild animals like bats, raccoons, skunks, and
foxes, although any mammal can get rabies.
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3. RABIES VIRUS
• Rabies virus belongs to the order Mononegavirales, viruses with a nonsegmented,
negative-stranded RNA genomes.
• Within this group, viruses with a distinct “bullet” shape are classified in the
Rhabdoviridae family, which includes at least three genera of animal viruses,
Lyssavirus, Ephemerovirus, and Vesiculovirus.
• The genus Lyssavirus includes rabies virus, Lagos bat, Mokola virus, Duvenhage
virus, European bat virus 1 & 2 and Australian bat virus.
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4. STRUCTURE
• 180 nm long and 75 nm wide.
• The rabies genome encodes five proteins: nucleoprotein (N),
phosphoprotein (P), matrix protein (M), glycoprotein (G) and
polymerase (L).
• All rhabdoviruses have two major structural components:
• a helical ribonucleoprotein core (RNP)
• a surrounding envelope.
• In the RNP, genomic RNA is tightly encased by the
nucleoprotein.
• Two other viral proteins, the phosphoprotein and the large
protein (L-protein or polymerase) are associated with the RNP.
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5. STRUCTURE
• The glycoprotein forms
approximately 400 trimeric spikes
which are tightly arranged on the
surface of the virus.
• The M protein is associated both with
the envelope and the RNP and may
be the central protein of rhabdovirus
assembly.
• Rabies is an RNA virus. The genome
encodes 5 proteins designated as N,
P, M, G, and L. The arrangement of
these proteins and the RNA genome
determine the structure of the rabies
virus.
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6. GENOME
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7. LIFE CYCLE
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8. CLINICAL MANIFESTATION
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9. SYMPTOMS
• The first symptoms of rabies may be
very similar to those of the flu
including general weakness or
discomfort, fever, or headache. These
symptoms may last for days.
• There may be also discomfort or a
prickling or itching sensation at the
site of the bite, progressing within
days to acute symptoms of cerebral
dysfunction, anxiety, confusion, and
agitation.
• delirium, abnormal behavior,
hallucinations, hydrophobia (fear of
water), and insomnia.
• The acute period of disease typically ends
after 2 to 10 days.
• Once clinical signs of rabies appear, the
disease is nearly always fatal, and
treatment is typically supportive. To date
less than 20 cases of human survival from
clinical rabies have been documented,
and only a few survivors had no history of
pre- or postexposure prophylaxis.
•
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10. DIAGNOSIS
• Diagnosis in animals and humans
• Direct Fluorescent antibody test
• Histologic examination
• Immunohistochemistry
• Electron Microscopy
• Amplification methods
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11. TREATMENT
• If a person is bitten or scratched by an animal that
may have rabies, or if the animal licks an open
wound, the individual should immediately wash any
bites and scratches for 15 minutes with soapy water,
povidone iodine, or detergent. This might minimize
the number of viral particles.
• Then they must seek medical help at once.
• After exposure and before symptoms begin, a series
of shots can prevent the virus from thriving. This is
usually effective.
A fast-acting dose of rabies immune globulin: Delivered as
soon as possible, close to the bite wound, this can prevent the
virus from infecting the individual.
A series of rabies vaccines: These will be injected into the arm
over the next 2 to 4 weeks. These will train the body to fight the
virus whenever it finds it.
• It is not usually possible to find out whether the animal has
rabies or not. It is safest to assume the worst and begin the
course of shots.
• A small number of people have survived rabies, but most cases
are fatal once the symptoms develop. There is no effective
treatment at this stage.
• A person with symptoms should be made as comfortable as
possible. They may need breathing assistance.
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14. PREVENTION IN PETS
• First, visit your veterinarian with your pet on a regular basis and keep rabies
vaccinations up-to-date for all cats, ferrets, and dogs.
• Second, maintain control of your pets by keeping cats and ferrets indoors and
keeping dogs under direct supervision.
• Third, spay or neuter your pets to help reduce the number of unwanted pets that
may not be properly cared for or vaccinated regularly.
• Finally, call animal control to remove all stray animals from your neighborhood
since these animals may be unvaccinated or ill.
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15. PREVENTION
• Vaccinate pets: Find out how often you need to vaccinate your cat, dog, ferret, and other domestic or farm animals,
and keep up the vaccinations.
• Protect small pets: Some pets cannot be vaccinated, so they should be kept in a cage or inside the house to prevent
contact with wild predators.
• Keep pets confined: Pets should be safely confined when at home, and supervised when outside.
• Report strays to the local authorities: Contact local animal control officials or police departments if you see animals
roaming
• Do not approach wild animals: Animals with rabies are likely to be less cautious than usual, and they may be more
likely to approach people.
• Keep bats out of the home: Seal your home to prevent bats from nesting. Call an expert to remove any bats that are
already present.
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16. CLARIFICATION
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sivasan91@gmail.com

17. QUESTIONS TO THINK
• Structure of Rabies virus
• Is therapy helpful in the treatment of Rabies viral disease?
• Prevention methods for rabies
• mechanism of Rabies genes in the activation of antigens? (any one gene)
• method to diagnose the Rabies
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