week 9

• What is the first step of the viral life cycle?

  Attachment to host cells
• What are the main phases of the virus life cycle?

  • Virus entry and uncoating
  • Virus protein translation
  • Genome replication
  • Virus assembly
  • Virus release and transmission
• Why do viruses not "grow" like cells?

  Viruses do not grow and divide; they assemble
• What happens during the eclipse phase of the viral life cycle?

  Viruses are manufactured within the host cells
• What is the role of glycoproteins in virus entry?

  They recognize attachment and entry receptors
• What is the significance of the Central Dogma of Molecular Biology in relation to viruses?

  RNA viruses are an exception as they do not involve DNA
• What is the function of RNA dependent RNA polymerase in ss (+) RNA viruses?

  It is responsible for replication in the cytoplasm
• What is the Baltimore classification of viral genomes?

  It categorizes viruses into seven classes based on their genome type
• What are the seven classes of viral genomes in the Baltimore classification?

  1. dsDNA
  2. gapped dsDNA
  3. ssDNA
  4. dsRNA
  5. ss (+) RNA
  6. ss (-) RNA
  7. ss (+) RNA with DNA intermediate
• What is the replication site for dsDNA viruses like Herpes simplex viruses?

  Replication occurs in the cell nucleus
• What is the role of reverse transcriptase in retroviruses?

  It converts RNA into DNA during replication
• What is the structure of the viral capsid?

  It can be helical, icosahedral, or scaffolded icosahedral
• How do enveloped viruses typically egress from the host cell?

  They use the secretory pathway for assembly and maturation
• What are the methods of viral transmission?

  • Direct cell-to-cell
  • Paracellular transport through proteic channels
  • Cell-free spreading through vesicular transport
• What is the significance of antivirals in viral infections?

  They can inhibit many steps of the viral life cycle
• Why is knowledge of cell biology important for understanding viruses?

  It helps in understanding how viruses depend on host cells for replication
• What are structural proteins in viruses?

  Proteins that form the virus structure, such as capsids
• What is the impact of the Zika virus on infants?

  It can cause microcephaly in infants infected during pregnancy
• What is the role of viroporin in viral infections?

  It induces rupture of the cell membrane
• What was the estimated death toll of the 1918 Influenza Pandemic?

  20-30 million deaths
• What is the difference between lytic and non-lytic viral egress?

  Lytic egress involves cell lysis, while non-lytic does not
• What is the main focus of the learning outcomes for respiratory viruses?

  Understanding key facts about respiratory viruses
• What are the key facts to understand about respiratory viruses?

  Burden, history, epidemiology, virology, pathogenesis
• What are the common upper respiratory symptoms of viral infections?

  • Runny nose
  • Cough
  • Sore throat

  
• What are the common lower respiratory complications of viral infections?

  • Croup (in children)
  • Bronchiolitis
  • Pneumonia
  • Respiratory failure
• What is the most common cause of respiratory infection in infants?

  Respiratory Syncytial Virus (RSV)

  
• At what age are most individuals infected by RSV?

  By age 2
• Who is most at risk for severe RSV infection?

  Very young, very old, and immunocompromised
• How many RSV infections occur worldwide each year?

  33 million infections
• What is the annual hospitalization rate for RSV infections?

  3.4 million hospitalizations
• How many deaths per year are attributed to RSV?

  Up to 199,000 deaths
• What type of virus is RSV classified as?

  Enveloped, negative-sense ssRNA virus
• Into how many subtypes is RSV divided?

  Two subtypes: A and B
• How many clades of RSV A and B have been identified?

  16 RSV A and 22 RSV B clades
• What is the structure of RSV virions?

  Pleomorphic with 10 genes encoding 11 proteins
• What are the key mechanisms RSV uses to evade the immune response?

  • Inhibiting apoptosis
  • Inhibiting IFN signaling
  • RNA binding by nucleoprotein
  • Delaying apoptosis
  • Viral attachment via glycoprotein

  
• What is the primary method for diagnosing RSV?

  PCR as part of a respiratory panel
• What is the purpose of diagnosing RSV?

  Patient management and isolation
• Is there a vaccine available for RSV?

  No vaccine available
• What is the prophylactic option for RSV?

  Palivizumab, a humanized monoclonal antibody