Download MEASLES (RUBEOLA) VIRUS

MEASLES (RUBEOLA)
VIRUS
Genus Morbillivirus
PARAMYXOVIRIDAE
Paramyxovirinae
Genus respirovirus:
Genus Rubulavirus
Genus morbillivirus
Pneumovirinae
Genus Pneumovirus
RSV
Genus Metapneumovirus
MEASLES (RUBEOLA)
VIRUS
• Rubeola virus is the cause of
measles infection
• Measles is an acute, highly
infectious disease characterized
by:
• a maculopapular rash,
• fever
and
• respiratory symptoms.
MEASLES (RUBEOLA) VIRUS
Structure:
• Its structure is similar to that of
paramyxo-viruses, with one exception that
the haemagglutinin neuraminidase spikes
present on the viral envelope has:
• Haemagglutinin activity
• Lack neuraminidase activity.
• One serotype only exist.
Pathogenesis and Pathology:
• Transmission occurs through droplet
infection.
• Virus multiplies locally in the respiratory
epithelial cells,
• The infection then spreads to the
regional lymphoid tissue, where further
multiplication occurs.
Pathogenesis and Pathology:
• Primary viraemia disseminates the virus, in
the reticuloendothelial system.
• A secondary viraemia seeds the epithelial
surfaces of the body including:
• the skin,
• respiratory tract
• conjunctiva.
NOTE: The virus replicates in certain
lymphocytes
The hallmark of measles
“measles rash”
Reaction between
INFECTED ENDOTHELIAL CELLS
IMMUNE T CELLS
Lining small blood vessels
RASH
Complications
1-
Postinfectious encephalitis is
believed to be immune mediated,
occurs after rash.
2- Immunocompromised patients with
measles may have continuing
infection, resulting in death.
Complications
3. Subacute sclerosing panencephalitis (SSPE):
- occurs in 7 in 106 patients years after a
measles infection,
- SSPE results from ongoing replication of
defective measles virus in the central nervous
system.
• Infection spreads directly from cell to cell
without mature virus release.
Laboratory Diagnosis:
A. Direct detection of virus antigen
in clinical specimens could be
achieved by immuno fluorescent
technique.
B. Isolation:
Specimens for viral isolation include
nasopharyngeal swab and blood samples.
Cell Line: Monkey or human kidney are
appropriate cells for virus isolation.
Out come:
- Cytopathic effect in the form of
multinucleated giant cells is detected.
- Haemadsorption or
- Immunofluorescence assays are used to
confirm measles antigen in the inoculated
cultures.
C. Serology:
• HAI is the most practical method.
• CFT
&
• NT tests all may be used to measure
measles antibodies
Treatment:
• Treatment is symptomatic.
• No available antiviral drugs.
Prevention and Control:
• A live attenuated viral vaccine is available.
TIME OF ADMINISTRATION:
• The vaccine is administered subcutaneously
either in a monovalent form (measles virus
vaccine) at the age of nine months, and it is a
part of the compulsory vaccination schedule in
Egypt.
•
Or it may be administered at age of 15
months in combination with mumps
and rubella vaccine (MMR vaccine).
• The vaccine is safe and gives life
long immunity.
• Few side effects may be present.
Live attenuated viral
vaccines
Are contra indicated in:
pregnant
&
immune compromised host