MYVR-RSV

• RESPIRATORY SYNCYTIAL VIRUS (RSV)

  Family = Paramyxoviridae

  Genus = Pneumovirus

  • Incubation period = 2-8 days
  • Peak season = winter and early spring
  • Temperate zones = 2-5 months; yearly outbreaks
• CLINICAL PRESENTATION

  • attacks ciliated columnar epithelial cells
  • from nasopharyngeal to distal bronchi
  • Infants < 1 year old = common to severe lower respiratory tract disease (bronchiolitis and pneumonia) worldwide; narrow terminal airways occluded by necrotic epithelial cells
  • Critical cases to = premature infants, children with comorbidities, and transplant recipient
  • Causative agents of = croup/viral bronchitis and bronchiolotis/pneumonia
  • Infection does not confer immunity = multiple infections throughout life; asymptomatic adults may carry the virus in the nares
• MORPHOLOGY

  • enveloped, negative-sense ssRNA
  • Spherical; 15-250 nm

  Transmembrane Protein

  • Attachment glycoprotein (G)
  • Fusion glycoproteins (F) = binds to the receptor of RSV
  • Small hydrophobic protein (H) = pathogenesis; prevents apoptosis of the host cell
  • Matrix = stability and rigidity; located inner envelope

  A & B subtypes = based on F and G protein reactivity with monoclonal antibodies

  A subtype = most common
• LAB DIAGNOSIS

  • adenovirus vaccine for serotype 4 and 7
  • Isolation = nasopharyngeal swabs and washings; fragile and labile --> transport specimen ASAP
  • Microscopy = direct fluorescence antibody staining of respiratory secretions
  • Serology = enzyme immunoassay and commercial antigen detection kit
  • Cell culture = HEP2 and A549 > CPE2 (HEP2 = human laryngeal carcinoma)
  • Molecular = nucleic acid-based PCR
  • Capable of forming SYNCYTIA = fusion of infected cells into a large multinucleated syncytium