SARS-CoV2 belongs to Corona Virus Family which is responsible for causing Common Cold in about 10-30% of all cold cases. Most of the viruses are either RNA or DNA in genetic makeup. SARS-CoV2 is a positive strand RNA virus with unusually large Genome. It is 80% identical at sequence level to SARS-CoV1 from 2003 Pandemic which was heavily studied at that time and that is why there is a lot of understanding about behavior of Corona Viruses.
SARS-CoV2 is Encapsulated meaning it has an envelope around it which is very lipophilic or “Lipid loving” that makes it easily destructible with just about any disinfectant specially soap. SARS-CoV2. It affects Humans and Animals equally and closely related Corona Virus can hop from one species to another and Humans too. SARS-CoV2 is believed to hopped to Humans from Bats likely via intermediary species which is not yet identified.
So for the infection to occur SARS-CoV2 has to bind to human cells to gain entry into the cell, which they do via a Spike like structure called S protein. The S protein binds to ACE 2 Receptors present on Cell surface in Human Bodies.
These ACE 2 receptors are present in Respiratory and GI tracts and that explains why some patients with COVID 19 get not just Respiratory but also GI symptoms like Abdominal pain and Diarrhea. So following binding, S Protein gets activated. Once it is activated, a fusion occurs which allows Virus to release its RNA Strand into Human Cell thereby causing infection. This occurs when
Human Ribosome translates and makes Poly Proteins from RNA. These Poly proteins then gets cleaved into smaller pieces, all of which combines to make Replicase and RNA Complex meaning multiplication of Virus occurs. These Bud out and release Virus particles from membrane thereby causing symptoms of the disease.
Now why is it important to know the life cycle of Virus. Because the protease and replicase that help virus to from and multiply are the target for AntiViral therapies for SARS-CoV2. In other words, drugs inhibits Replicase and Protease in order to stop the Virus from Replicating and Growing
Like I said previously, SARS-CoV2 is very similar to SARS-CoV1 from 2003 pandemic which was heavily studied to find drugs and Vaccines, most of that research applies directly to SARS-CoV2, so we are already ahead in a game and I am hoping we will find Vaccine and Cure to this deadly disease soon.