Respiratory Viruses

Respiratory Viruses

1. INFLUENZA

   • Intro
     • Orthomyxoviridae
     • SS -ve RNA
   • Symptoms
     • Respiratory
     • Gastric
     • Muscular
     • Systemic
     • Central (headaches)
     • Complications
       • Pneumonia
   • Susceptibility factors
     • Age
     • Immuno status
     • Pregnancy
     • Underlying disease
   • Structure
     • M1 matrix protein
     • M2 ion channel
       • Not type B
     • 8 -ve RNA
     • RNA polymerase complex
     • NA
       • Cleaves sialic acid
         • Allows viral release
       • Tetramer
     • HA
       • Binds host sialic acid
         • viral entry
           • Endosome acidification
       • Activated by proteolysis
     • Non structural proteins
       • Promote apoptosis
       • Inhibit IFN mediated viral responses
   • Novel human viruses
     • Animal reservoirs
       • H1-3 & N1-2
         • Stable lineages in humans
     • Antigenic drift
       • Type A & B
       • mutations
         • E190D of H1
           • Increases cleft width
             • Avian = small cleft
             • Human = wider
     • Antigenic shift
       • Type A
       • Coinfection/RNA exchange
         • HA host specificity
           • Pig trachea
             • 2,3 = avian
             • 2,6 = human
   • Drug treatment
     • Amantadine & rimantidine
       • Block M2 ion channel
       • Prevent endosome fusion and nuclear transport
       • Gastro and neuro implication
     • NA inhibitors
       • Relenza
       • Tamiflu
   • Vaccines
     • Contain A & B strains

2. SARS

   • RNA +ve
     • 11 ORF
   • Diagnosis
     • Thermal imaging
     • RT-PCR & serological tests
   • Symptoms
     • 1. Initial fever
     • 2.Cough/short of breath
     • 3.Pneumonia
   • Coronaviridae family
   • Structure
     • S (Spike)
       • Entry
       • ACE2 R
       • 3 domains
         • core domain
           • bound to fusion protein stem
         • RBD
     • N (helical capsid)
     • Membrane glycoprotein
   • Potential therapuetic targets
     • Ab against S
     • Fusion inhibitors
       • HA
     • Protease inhibitors
     • Receptor blockade
     • Release inhibitors
       • NA

3. RHINOVIRUS

   • Structure
     • SS +ve RNA
     • UTRs
     • 4 capsid proteins
   • Binds ICAM-1
     • Has immunoglobulin-like domain
   • intro
     • 100 picornaviruses
     • Optimal temp = 33
       • Nasal passage
     • damage ciliated epithelium
       • Predispose 2ndary infection