Family:

Paramyxoviridae

Genome:

Negative sense, single stranded RNA

• The Family includes:
  Morbillivirus
  Pneumovirus
  Paramyxovirus
  
• Genome codes for approximately six proteins

Important Proteins:

• Haemagglutinin (HA)
• M (matrix) Protein
• F (fusion) Protein
  • Cleaved from a precursor protein
• Contains a viral RNA transcriptase
• Lacks neuraminadase

Infection and Replication:

• Virus fuses with the cell membrane allowing the viral genome to enter the cytoplasm
• Fusion of infected cells occurs though the F protein to form characteristic syncytia
• Virus release occurs from the cell by budding

Pathology:

• Also called morbilli or rubeola
• Droplets spread the infection via the respiratory tract (replicating within the epithelial cells)-extremely contagious
• A maculopapular rash (caused by an active immune response) appears on the face, spreading to the trunk and limbs approximately two weeks after infection. The rash is usually described as morbilliform (morbus-disease)
• Rash first appears as small red lesions on the buccal mucosa of the cheek - Koplik's spots
• Signs include fever, malaise, respiratory complications and occasional inflammation of the intestine
• Disease is usually self-limiting within a few days
• Differential diagnosis includes rubella (German measles), scarlet fever, infectious mononucleosis and infections due to other viruses (eg HHV-6)

Vaccination:

• Using an attenuated vaccine (single serotype) administered between one and 1.5 years
• Immunity is life-long
• Given in combination with mumps and rubella vaccines (MMR)