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