measles (rubeola) virus genus morbillivirus. paramyxoviridae paramyxovirinae genus respirovirus:...
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MEASLES (RUBEOLA) MEASLES (RUBEOLA) VIRUSVIRUS
MEASLES (RUBEOLA) MEASLES (RUBEOLA) VIRUSVIRUS
Genus MorbillivirusGenus Morbillivirus
PARAMYXOVIRIDAEParamyxovirinaeGenus respirovirus:Genus Rubulavirus Genus morbillivirusPneumovirinaeGenus Pneumovirus
RSVGenus Meta- pneumovirus
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.
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.
MEASLES (RUBEOLA) VIRUS
• 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
Pathogenesis and Pathology:
The hallmark of measles “measles
rash” Reaction between INFECTED ENDOTHELIAL CELLS IMMUNE T CELLS
Lining small blood vessels
RASH
Complications1- Postinfectious encephalitis is
believed to be immune mediated, occurs after rash.
2- Immunocompromised patients with measles may have continuing infection, resulting in death.
Complications3. 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