Rabies caused by rhabdovirus(rabies virus) through dog bite . introduction pathogenesis, symptoms, treatment and prevention methods.

1. RHABDOVIRUS
Ranjeet Kumar Taram
MSc.III sem (Microbiology)
S.o.S. in Life Science
Pt. Ravishankar Shukla University, Raipur
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2. CONTENTS
A. Rhabdovirus
• Introduction
• Classification
• Morphology
• Antigenic properties and host range
• Life cycle
B. Rabies virus
• Introduction
• Classification
• Epidemiology
• Pathogenesis
• Symptoms
• Clinical diagnosis
• Treatment
• Prevention
• Next generation vaccine
• References
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3. Introduction
• The term Rhabdovirus is derived from Greek word “rhabdos” meaning rod,
but virus have a bullet shape or bacilliform morphology.
• The family Rhabdoviridae consists of more than 100 viruses that infect a wide
variety of hosts including a vertebrate ,invertebrate and plants.
• It has been suggested that some rhabdovirus that infect plant may also infect
vertebrates.
• More over, one member Vesicular stomatitis virus infects several vertebrates
hosts, multiplies in Aedes mosquitoes and grow in leafhoppers , which are the
natural vector of maize mosaic virus, a plant rhabdovirus.
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4. Classification
• According to the ICTV report 2019 on virus classification
and taxon nomenclature the family rhabdoviridae
contains 30 genera and 191 species.
• The family rhabdoviridae fall into 4 groups based on the
RNA polymerase gene.
• The basal clade appears to be Novirhabdoviruses, which
infect fish.
• Cytorhabdoviruses and the Nucleorhabdoviruses, which
infect plants, are sister clades.
• Lyssaviruses which infect vertebrates and insects.
• Rhabdovirus that infects specifically mammals are
grouped in 2 genera :-
1. Vesiculovirus
2. Lyssavirus
Realm: Riboviria
Kingdom: Orthornavirae
Phylum: Negarnaviricota
Class: Monjiviricetes
Order: Mononegavirales
Family: Rhabdoviridae
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5. Morphology
• Common to all members of the family rhabdoviridae is a distinctive rod or bullet shape of
morphology.
• 180 x 75 nm in size with one end rounded or conical & the other end planar or concave.
• All rhabdoviruses have two major structural components: a helical ribonucleoprotein core (RNP)
and a surrounding envelope.
• The genome of rhabdovirus is single stranded ,non-segmented , negative sense RNA(-) molecule
that makes up about 2% of the virus particle.
• Most of the rhabdovirus contains five proteins :-
• 1. glycoprotein (G)- surface antigen.
• 2. matrix protein (M)- keep nucleoprotein condensed , important for assembly.
• 3. large protein (L)- RNA dependent RNA polymerase.
• 4. Non structural protein (NS)- phosphoprotein, L cofactor and various regulatory functions.
• 5. nucleoprotein (N)- RNA binding protein (coats the RNA).
• Virion also contains a lipid bilayer as a envelope which are derived entirely from the host cell.
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Fig. morphology of rhahbdovirus

7. Antigenic properties and host range
• The glycoprotein is the major antigenic determinant responsible for type
specificity and give rise to neutralizing the antibody.
• The Glycoprotein spike is responsible for attachment with host ,removal of
which by protease reduces infectivity more than 105 fold.
• The concept is that the terminal sialic acid in the carbohydrate chains of
virion is responsible for efficient infectivity and adsorption to host cells.
• The lipid bilayer also play some role in its infectivity .Exposure to
phospholipase reduces infectivity.
• It is suggested that phosphatidyl serine and phosphatidyl choline are receptor
site for rhabdovirus.
• Acetylcholine receptor on neural tissue have been postulated to be receptor
sites for attachment of rabies virus on the basis of reduced infectivity after
exposure to 𝛼- bungarotoxin and 𝛼- tubocurarine.
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8. • Rabies virus has hemolysis activity, optimally seen at 0 - 40C & pH 5.
• It is inactivated by heat 560C for 30 – 60 min or exposure of ether ,trypsin.
Rhabdovirus infect a wide variety of hosts
including a vertebrate ,invertebrate and plants.
ANIMALS –
All mammals are susceptible to Rhabdovirus.
Cattle, cats ,bats & foxes – Highly susceptible.
Skunks, opossums & fowl – relatively resistant.
Humans & dogs occupy an intermediate position.
Pups are more susceptible than adults.
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9. Life cycle
• When an infectious virion of the family Rhabdoviridae
encounters a susceptible host cell, the result is often a
series of events that terminates in release of progeny
virions and, frequently, death of the cell.
• Adsorption - attachment of virion to host cell by its
receptor that is glycoprotein spike.
• Penetration- fusion of virus with host cell surface
thereafter discharging the virus containing coated
vesicle into the cytoplasm.
• Uncoating – after endocytosis , the coated vesicle
fused with lysosome , thus resulting in release of
nucleocapsid.
• Transcription – this is the first metabolic event after
penetration and uncoating of rhabdovirus.
• N protein encapsulated RNA genome acts as a template
and L & NS proteins are required for transcription
initiation.
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10. • Translation - Translation of each of the mRNAs of
virion, proceeds immediately after, and in fact is
coupled with transcription.
• The glycoprotein is synthesized on endoplasmic
reticulum membrane associated polyribosomes by
means of signal sequence , step wise glycosylation.
• The other 4 protein are synthesized from
monocistronic m-RNA on cytoplasmic polyribosomes.
• Replication – virus contain ssRNA genome with a
negative polarity, meaning that their sequence is
complementary to the m-RNA.
• Full length of positive RNA strands are made to serve as
a template for the production of the negative strand.
• Assembly – the final assembly of virus from its
components takes place at plasma membrane of
infected host cells. viral nucleocapsid (N)protein is first
synthesized then assembles with RNA to form the
nucleocapsid and then remaining proteins are
assembled.
• Budding – budding of virions from the apical or
basolateral region of host cell membrane has been
extensively studied.
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11. Rabies
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12. Introduction
• Rabies lyssavirus, formerly Rabies virus
(RABV), is a neurotropic virus that causes
rabies in humans and animals.
• Rabies virus transmission can occur through
the saliva of infected animals and less
commonly through contact with human
saliva.
• Like many rhabdoviruses, Rabies lyssavirus
has an extremely wide host range.
• Generally it infect many mammalian species ,
while in the laboratory condition it has been
found that birds can be infected ,as well as
cell culture from mammals , birds, reptiles
and insects.
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Realm: Riboviria
Kingdom: Orthornavirae
Phylum: Negarnaviricota
Class: Monjiviricetes
Order: Mononegavirales
Family: Rhabdoviridae
Genus Lyssavirus
Species rabies lyssa virus
Classification

13. Epidemiology and burden of rabies
• Rabies is estimated to cause 59,000 human deaths annually in over 150 countries, with 95%
of cases occurring in Africa and Asia.
• Rabies is a major burden in Asia, with an estimated 35,172 human deaths per year.
• India accounts for 59.9% of rabies deaths in Asia and 35% of deaths globally. The cost of Post
Exposure Prophylaxis (PEP) is highest in Asia, with estimates up to US$ 1.5 billion per year.
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14. Pathogenesis
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15. Symptoms
Non specific symptoms
• Pruritus
• Paresthesia
• Pain
• Fever
• Malaise
• Irritability
• Headache
• Nausea
• Vomiting
• Agitation
• depression
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Paralytic symptoms
• Local muscle weakness
• Facial weakness
Encephalitic symptoms
• Confusion
• Hallucination
• Hypersalivation
• Hydrophobia
• Aerophobia
• Late complications (
cardiac failure ,
respiratory failure , multi
organ failure )
• coma

16. Clinical diagnosis
• Specimen – corneal smear ,skin biopsy (from neck and face),saliva ,brain(CSF).
• Types of diagnosis :-
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1.Rabies antigen detection
2. Viral detection
3.Antibody detection
4. Viral RNA detection
5. Negri body detection
1.Rabies antigen detection – from corneal smear by direct immunofluorescence
test. Direct immunofluorescence is done by using monoclonal antibodies tagged with
fluorescein isothiocyanate.
2.Viral isolation by –
Animal inoculation -Isolation of virus by intracerebral inoculation in mice attempted
from brain, CSF, saliva & urine .

17. • Cell lines inoculation -Isolation of virus in tissue culture cell lines . Mouse neuroblastoma ,[BHK]baby
hamster kidney cell lines are used .Identified by immunofluorescence.
3.Antibody detection – from CSF (imp.) and serum(late appearance).
• MNT – mouse neutralization test.
• RFF-IT- rapid fluorescence focus inhibition test.
• FAVN- fluorescent antibody neutralization virus test.
• IFA- indirect fluorescence assay.
• HAI- hemagglutination inhibition test.
• CFT- complement fixation test.
4.Viral RNA detection- Detection of rabies virus RNA by reverse transcriptase PCR is a sensitive and
specific molecular method.
5. Negri body detection – Negri body is eosinophilic inclusion but it has basophilic inner granules .Negri
body detection is accomplished by histopathological staining of brain biopsy(cerebral tissue).
H and E stain ,Seller’s stain are used .
Immunohistochemistry- peroxidase labelled specific antibodies are used to Negri body detection in
formalin fixed tissue. It is more sensitive and specific than staining methods.
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18. Treatment
• Post exposure treatment consists of :-
1.Local treatment of wound –
Wash wound immediately with soap and water preferably for 10 minutes.
Chemical treatment – alcohol tincture iodine ,any antiseptic.
Anti tetanus prophylaxis.
Antimicrobial –Amoxicillin , cloxacillin , cefuroxime.
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1.Local treatment of the wound
2. Administration of rabies immunoglobulin (passive immunization).
3. Immediate vaccination (active immunization).

19. 2.Administration of rabies immunoglobulin –
HRIG- Human Rabies immunoglobulin , horse anti rabies serum are used for passive immunization.
Booster doses are essential whenever anti rabies serum is given.
3.Immediate vaccination –
Vaccine is a fluid or dried preparation of Rabies “fixed” virus grown in the neural tissue of rabid animal such
as sheep, rabbit etc. or in embryonated duck egg or in cell culture .
A. Neural vaccine-
It contains 5% suspension of infected sheep brain (infected with fixed virus) .inactivated with phenol at 37 °C.
Vaccine available after inactivation with beta propiolactone.
B. Egg vaccine-
➢Duck egg vaccine – prepared from a fixed virus inactivated by beta propiolactone.
➢Live attenuated chick embryo vaccine.
C. Tissue culture vaccine –
➢Human diploid cell vaccine [HDCV].
➢Purified chick embryo cell vaccine [PCEC].
➢Purified Vero cell vaccine [PVRV].
➢Purified duck embryo vaccine [PDEV].
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20. Vaccine doses -
❖Intramuscular regimen [0-3-7-14-28]
➢1 ml doses given intramuscular deltoid (children - anterolateral aspect of thigh ).
➢Five doses of vaccine should be given on day 0 , 3 , 7 , 14 , 28.
❖Intra Dermal Schedule (0-3-7-28- 90)
➢Two site Intra Dermal Vaccination has been used in India , endorsed by WHO Expert Committee on
rabies.
➢0.2ml doses given at each two sites on day 0 , 3 , 7 & one site on days 28 , 90.
➢ Intradermal dose is 1/5th of intramuscular dose.
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21. Prevention
➢ Eliminating rabies in dogs and other pets-
eliminating rabies in dogs through vaccination. This has reduced the number of human rabies cases
prevention of human rabies through control of domestic dog rabies is a realistic goal.
➢Preventive immunization in people-
Pre-exposure immunization in people who have a high risk of getting infected with rabies virus . these
persons include veterinarians, animal handler ,traveller who will spent more than 1 month in
countries having a high rate of rabies infection.
It should be given on following days – 0-7-21 or 28 and 56th day.
➢Epidemiological surveillance-
Dog bites must be notifiable within national surveillance system on weekly basis.
Collected data should be processed and disseminated rapidly between different administrative levels .
Dog movement.
Dog vaccination status.
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22. Next generation rabies vaccines
• A number of experimental vaccines are under development that
may provide alternative ,safe and potent but less expensive
vaccine options. These include, recombinant viral vaccines, DNA
based rabies vaccine and oral rabies vaccine derived from plants.
➢ Recombinant rabies virus vectored vaccine –
To generate a more stable variants of rabies viral vaccine variety of
foreign genes inserted into viral genome .
➢ DNA based rabies vaccine –
For developing new generation rabies vaccine is to use a DNA based
or plasmid vaccine encoding the rabies glycoprotein gene.
➢ Oral rabies vaccine derived from plant –
Plants has provided new system for the large scale production of
recombinant protein at low cast , simplifying the production
process.
A variety of genetically engineered vaccines using Tobacco mosaic
virus and Tomato bushy stunt virus have been developed for
expressing for antigen in plants.
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23. References -
• Wagner, Robert R. "Rhabdovirus biology and infection." The
Rhabdoviruses. Springer, Boston, MA, 1987. 9-74.
• http://80.82.78.35/get.php?md5=c30dd6e4625221d68cb4f038f1
90ef62&key=DG4GTFJ8K1B5GU92&mirr=1
• https://www.who.int/rabies/epidemiology/en/#:~:text=Rabies%
20is%20estimated%20to%20cause,the%20true%20burden%20o
f%20disease.
• https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3623496/
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24. Thank You………
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