Question

a. List and describe the 6 steps if viral replication.

b. In general, an antiviral would have to do what to deactivate the virus in your body? Explain.

c. Do you have to sterilize an item to deactivate the SARS-CoV-2 virus? Explain.

d. Using the terms antigenic drift and antigenic shift, explain the COVID virus and where we are today.

Answer 1

A. Steps of viral replication:

1. Attachment: the infecting virus attaches itself to a complementary receptor on the host cell through the attachment proteins in the capsid or the glycoprotein in the viral envelope.

2. Penetration: it involves injecting the genetic material into the host cell through endocytosis.

3. Uncoating: it involves disassembly of the virus in the host cell which leads to the release of replication competent viral genome.

4. Replication: this involves synthesis of viral genome and depends on the viral genome itself. The viruses usually use host cell proteins and enzymes for the amplification and result in the synthesis of messenger RNA (mRNA).

5. Assembly: The viral mRNA directs the host cell to synthesize viral enzymes and capsid proteins for the assembly of infectious virion.

6. Release: this is the last step which is involved in the release of the virions produced and infect adjacent cells and repeat the replication cycle.

B. An approach to inhibit the virus in the host body includes inhibition of DNA synthesis during viral replication. And general strategy utilizes analogue molecules that can mimic the structure of a nucleoside but only difference is that it lacks free 3′ end needed for the addition of the next nucleotide. This prevents the incorporation of the next nucleotide and terminates the elongation of the DNA chain.

C. SARS-CoV 2 virus is responsible for the ongoing pandemic. It is known to spread through respiratory droplets of the infected person and has been rapidly transmitted through asymptomatic individual (those who are infected but do not show any symptoms). So the droplets of these infected individuals on surfaces of various materials can be seen as potential carrier. Evidence have suggested that SARS-CoV-2 may remain viable for hours to days on these surfaces. Sterilization of such surfaces may cease the transmission and also result in deactivation as host cell isn't available.

D. To fight the SARS-CoV 2 virus long term immunity is the only potential defender. This depends on 2 factors: strength of the immune response and the rate of evolution of the viral genome (how rapid can it evolve and change to adapt to the environment). The latter is differentiated into: antigenic drift and antigenic shift.

Antigenic drift refers to slow and gradual changes which may include small changes taking place during each replication cycle. On the contrary antigenic shift occurs when a virus experiences a big change in one replication cycle. This can happen if the genome of a virus is split up into different pieces or when two different viruses infect the same cell at the same time.

In the current scenario, it can be concluded that SARS-CoV-2 is only evolving using antigenic drift, the slow and gradual method.