1. RABIES VIRUS
A seminar on
Prepared by: Rupam saikia
In the guidance of Mr.
Manoranjan Barmam
(Assistant professor, B. Voc.
MLT) Chaiduar college
2. Introduction
what is rabies ?
Rabies virus is a neurotropic virus that causes rabies in
human and animals.
Rabies transmission can occur through biting, scratching,
contact of saliva on cut, eyes,nose, mouth by infected or
host animal.
Generally dog is the primary host but it can also
transmitted by other animals like
foxes,wolves,cat,monkey,jakele etc.
4. Structure
The Rabies virus has a bullet
like shape with a length of
about 180nm and a cross-
sectional diameter of about
75nm. One end is rounded or
conical and the other end is
planer or concave. The
lipoprotein envelope carries
knob-like spikes composed of
glycoprotein (G) spikes do not
cover the planner end of the
virion.
5. Infection
Rabies virus causes ‘Rabies’ in human. After inoculation
the rabies travels quickly along the peripheral nervous
system.The retrograde axonal transport of rabies virus to
the CNS is the key steps of pathogenesis during natural
infection.
From the CNS the virus further spread to other organs.
The salivary gland located in the tissues of the mouth
and cheeks receive high concentration of the virus, thus
allowing it to be further transmitted due to projectile
salivation. Fatality can occur from two days to five years
from the time of initial infection.
7. Clinical spectrum
The clinical spectrum can be divided into three phases-
1. Prodromal phase: the prodrome, lasting 2-10days, may
show any of the following nonspecific symptoms:
malaise, anorexia, headache, photophobia, nausea and
vomiting, sore throat and fever.
2. Acute Neurologic phase: During the acute neurologic
phase, which lasts 2-7days, patients show signs of
nervous system dysfunction such as hervousness,
apprehension, hallucinations and bizarre behaviour.
Hydrophobia is also observed in this phase.
8. Clinical spectrum
Hydrophobia: The pathognomonic feature is difficulty
in. Drinking, together with intense thirst. Patients
may be able to swallow dry solids but not liquids.
Attempts to drink bring on such painful spasms of the
pharynx and larynx producing choking or gagging that
patients develop a dread of even the sight or sound of
water.
3.Coma: Patients who survive the stage of acute
neurological involvement leps into coma, which may last
for hours or days. Death usually occurs within 1-6 days
due to respiratory arrest during convulsions.
9. Laboratory Diagnosis
Several tests are necessary to diagnose rabies anti-
mortem (before death) in human, no single test is sufficient.
Test are performed on sample of saliva, serum, spinal fluid
and skin biopsies of hair follicles at the nape ot the nack.
Saliva can be tested by virus isolating or reverse
transcription followed by polymerase chain reaction (RT-
PCR). Serum and spinal fluid are tested for antibodies to
rabies virus. Skin biopsy specimens are examined for rabies
antigen in the cutaneous nerve at the base of the hair
follicles.
10. Prevention and control
There is no cure for the clinical diseas, so prevention is
the only way to control it. There are several ways to
control rabies, as mentioned as follows:
11. Prevention and control
The vaccination is also a
important factor to control
rabies. There are a number of
vaccines available that are both
safe and effective. They can be
used to prevent rabies before and
for a period of time after
exposure to the virus such as a
dog or bat bite.
World Rabies Day is an
international awareness campaign
coordinated by the “Global
alliance for rabies control”, US.
