MEASLES (RUBEOLA) VIRUS Genus Morbillivirus

PARAMYXOVIRIDAE Paramyxovirinae Genus respirovirus: Genus Rubulavirus Genus morbillivirus Pneumovirinae Genus Pneumovirus RSV Genus 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

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 10 6 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