The Covid-19 virus that is moving  in Bengal is increasingly being found to be an indigenous triple-mutation (B.1.618), only the second one identified from India after the double mutant type (B.1.617) reported last month.

About  Coronaviruses -

Coronaviruses are a group of related RNA viruses that cause diseases in mammals and birds. In humans and birds, they cause respiratory tract infections that can range from mild to lethal.

 Mild illnesses in humans include some cases of the common cold (which is also caused by other viruses, predominantly rhinoviruses), while more lethal varieties can cause SARS, MERS, and COVID-19. In cows and pigs they cause diarrhea .

 Coronaviruses  are enveloped viruses with a positive-sense single-stranded RNA genome , one of the largest among RNA viruses.

 They have characteristic club-shaped spikes that project from their surface, which in electron micrographs create an image reminiscent of the solar corona, from which their name derives .

What is double mutant virus?

The B.1.617 or “double mutant” Indian variant carries two mutations including the L452R and E484Q which have been seen separately before in other variants but never together in one variant

Changes occur in any virus and this is a natural process. Let's suppose the coronavirus is round in shape like a ball and the thorns that are attached to it are called spikes which contain genetic material.

There are constant changes in the virus and this is called a mutation. When the virus mutates, it takes the form of a new strain and creates a distinct identity of its own.

We call it a new variant or new strain and this is what the double mutant virus is made of.

What is Triple  mutant virus?

Tipple Mutants means in addition to the two mutations, it also has V382L in its Spike. This is a sub-lineage of B.1.617.