Resp 9 Flashcards
(15 cards)
What are coronaviruses and how are they classified?
Enveloped, single-stranded RNA viruses named for solar corona-like projections. Seven human strains
What receptors and cells are targeted by coronaviruses?
They use receptors like 9-O-acetylated sialic acids or ACE2 (SARS-CoV-2) to enter host cells such as non-ciliated bronchial epithelial cells.
Summarise SARS-CoV and MERS-CoV.
SARS-CoV (2003): causes severe respiratory illness. MERS-CoV (2012) Spreads via close contact and evades immune response.
Describe SARS-CoV-2 origin, structure, and entry mechanism.
Emerged in 2019, likely from bats/pangolins. Shares ~80–90% genome similarity with bat CoVs. Composed of Spike (S), Nucleocapsid (N), Membrane (M), and Envelope (E) proteins. Spike protein binds ACE2 for cell entry.
How is SARS-CoV-2 transmitted and what are the global stats?
Spread by contact, droplets (<1m), airborne aerosols (<5 µm), and fomites.
What is Long Covid and how common is it?
Affects ~10% of severe Covid-19 cases. Involves 200+ symptoms and multisystem effects. Over 65 million affected globally.
What are VOIs, VOCs, and VUMs?
VOIs = Variants of Interest (potential concern); VOCs = Variants of Concern (confirmed increased severity/transmissibility); VUMs = Variants Under Monitoring.
What immunomodulators are used in severe Covid-19?
Dexamethasone (reduces mortality), Tocilizumab (blocks IL-6R, limits cytokine storm), Baricitinib (JAK1/2 inhibitor, reduces inflammation but may increase VTE risk).
What antivirals are used for Covid-19?
Paxlovid (nirmatrelvir + ritonavir): Mpro inhibitor with drug interaction risk.
Remdesivir: RNA polymerase inhibitor, ATP analogue.
Molnupiravir: RNA mutagen, inhibits replication.
Sotrovimab: Monoclonal antibody targeting spike RBD, promotes immune clearance via ADCC/ADCP.
What are the main types and characteristics of influenza viruses?
Types A, B, C, D. A and B cause epidemics. A has 18 HA and 11 NA subtypes (130+ combinations). C = mild illness, D = cattle.
How does influenza spread and who is most affected?
Aerosols, droplets. A = 80% of cases; B = more common in children (0–18 years). Most contagious in first 3–4 days after symptoms begin.
What is the difference between antigenic drift and shift?
Drift = Small point mutations → seasonal epidemics. Shift = Major reassortment → pandemics (Influenza A only), occurs in ‘mixing vessels’ like pigs.
Describe avian influenza and its zoonotic risk.
Wild waterfowl = reservoir. Human infections mostly H5, H7, H9. H5N1 and H7N9 cause severe pneumonia (~50% fatality). Zoonotic transmission via direct contact or reassortment.
What is included in the UK flu vaccine and who gets it?
Trivalent: 2 A strains + 1 B strain. ~70–80% protection. Given to elderly, pregnant women, immunocompromised, children with chronic conditions, and healthcare workers. Nasal spray for 2–18-year-olds.
What antivirals are used for influenza and how do they work?
Oseltamivir (oral), Zanamivir (inhaled/IV): Neuraminidase inhibitors that prevent virus release. Baloxavir marboxil: Endonuclease inhibitor, blocks cap-snatching in viral mRNA synthesis.
