coronaviruses Flashcards
describe the coronavirus structure regarding, genetics, size, no of spike proteins and which animals it infects
ssRNA virus, w120nm, around 80 spikes per virion, and affects mainly mammals and birds.
Has an envelope, with spike proteins, envelope and membrane proteins. Then nuclecapsid protein inside with ssRNA
Other coronaviruses
SARS-Cov-1, MERS, cov-2
What do two binding sites of covid-19 bind to? What happens next in infection?
ACE-2 receptor and directly to the membrane. Causes receptor-mediated endocytosis, binds RSS2 which hydrolysis connections between ACE-virus and the virion and spike.
What is the effect of alkalization and cathepsins on coronavirus in the cytoplasm?
Releases the virus into the cytoplasm to enable the translation of RNA in the cytoplasm (and nucleus)
How many non-structural proteins, and what are examples of structural proteins?
16 non-structural proteins. non-structural are e.g. spike and surface glycoproteins.
Or exoribonuclease, which provides resistance against e.g. drugs targeting the RNA polymerase (because it can do proofreading to maintain high fidelity)
What is the basic reproduction number?
at start of pandemic, describes how many people will be infected by one person on average in a homogenous population where everyone is equally susceptible.
4 things that can affect R0
How many people are susceptible.
population density.
How infective it is.
Rate of dissapearnece (includes duration of disease and deaths)
Re?
no of people who can be infected at any one time and will change with time.
the equation for calculating the percentage of people needed to be vaccinated to suppress disease.
R0= Re (1-Pi)
number of people who aren’t immune
supected case?
probable?
confirmed?
1) clinical symptoms
2) testing inconclusive
3) confirmed by lab test irrespective of symptoms.
steps of pcr test?
poly T primer and reverse transcriptase, then cDNA formation with DNA polymerase. Then PCR amplification.
why might you get false positives?
contamination of virus in lab.
cross reactivity with another virus.
shedding of viral proteins after resolution of infection.
What can affect how much false positives impact results?
Prevalence rate. Smaller the prevalence rate the more also positives are going to be skew results.
what are the two broad aims of antiviral drug therapies?
prevent release from endosomes, and inhibit reproduction in cells e.g. via targeting of exoribonuclease/RNA pol/ protease.
