SARS-CoV-2 Flashcards
What is the structure of the COVID-19 virus?
Large (100nm diameter), enveloped, that is a positive single strand RNA.
It is a pleomorphic particle with a distinctive arrangement of spike proteins.
How does COVID-19 replicate, and what is the replication time?
The positive single strand RNA is used as mRNA for replication using the RNA-dependent RNA polymerase, synthesising viral proteins.
The positive strand is converted into a negative strand which is then used as a template for new positive RNA strands to be packaged into new particles, with the viral proteins.
The replication time is approximately 10 hours.
How does COVID-19 gain entry into cells?
It has a spike protein (glycoprotein) which binds to Ace2 proteins (receptors), expressed particularly in the lung, heart, kidney and GI. It then enters via receptor-mediated endocytosis.
Why does COVID-19 have a high mutation rate?
It’s replication time is 10 hours, which is relatively short, and the RNA-dependent RNA polymerase is error prone.
What kind of infection does COVID-19 cause?
It causes respiratory infections, that is highly infectious, but typically causes mild symptoms.
Where did COVID-19 originate from?
It originated in Wuhan from bats and caused human infection through zoonotic transfer.
How does COVID-19 spread?
Through the respiratory route with coughing, sneezing and inhaling:
- Small droplets (<5micrometers in diameter) can evaporate into droplet nuclei and stay suspended in the air for a long time. Coughing produces droplets of around 1micrometer.
- Large droplets (>5micrometers in diameter) fall onto surfaces and can survive there for a number of days, which can be transported by hands onto mucous membranes (eyes, nose and mouth). Sneezing produced droplets of around 100micrometers.
What are the symptoms of COVID-19, and who does it affect more?
Infected patients can range from asymptomatic to death - affecting immunocompromised and the elderly much more. Major symptoms include:
- Fever.
- Headache.
- Dry cough.
- Loss of taste/ smell.
- Extreme fatigue.
- Sore throat.
- Sneezing.
- Muscle/ joint pain.
How can COVID-19 be diagnosed?
Nasopharyngeal swabs using reverse-transcriptase PCR (RT-PCR).
Lateral flow tests test for antigen or antibodies through nasal or oral swabs.
How can COVID-19 be treated?
Several different vaccines - new mRNA vaccines, which stimulate the body’s cells to make the COVID-19 protein, triggering an immune response, forming memory cells.
Dexamethasone (anti-inflammatory) and given oxygen.
