Cases of Covid-19 first emerged in the late 2019, when a
mysterious illness was reported in Wuhan, China. The cause of the disease was
soon confirmed as a new kind of coronavirus, and the infection has since spread
to almost every country around the world and has become a pandemic.
There is a popular belief that the virus could have originated
from a laboratory in Wuhan, China. The analysis of the public genome sequence
data from Covid-19 found no evidence that the virus was made in a factory or
otherwise genetically engineered. By comparing the available genome sequence
data for known coronavirus strains, scientists have firmly concluded that the
Covid-19 virus originated through natural processes.
Coronaviruses are a large family of viruses that can cause
illnesses ranging widely in severity.
The first known severe illness caused by coronavirus emerged in
2003 with the Severe Acute Respiratory Syndrome ( SARS ) epidemic in China.
A second outbreak of the severe illness began in 2012 in Saudi
Arabia with the Middle East Respiratory Syndrome ( MERS ).
The scientists have analyzed the transmembrane proteins ( spike
proteins ) and the armatures on the outside of the virus that it uses to grab
and penetrate the outer walls of the human and animal cells. They focused on
two important features; a kind of grappling hook that grips onto host cells and
a molecular can opener that allows the virus to crack open and enter the host
cells.
Based on the genomic sequencing analyzes, the scientists concluded
that the most likely origins of Covid-19 virus followed two possible scenarios.
In the first scenario, the virus could have evolved to its current
pathogenic state through natural selection in an animal host and then jumped to
humans. The researchers suggest bats as a possible animal host as it is little
similar to a bat coronavirus. However, there is an important difference between
the bat coronavirus and Covid-19. The transmembrane proteins which bind to the
receptors on the surface of the cells to gain access are different in the two
viruses.
In the second scenario, a non-pathogenic version of the virus
could have jumped from an animal host into humans and then evolved to the
current pathogenic state within the human population. For instance, the
coronavirus in pangolins have a Resource Description and Access ( RDA )
structure very similar to that of Covid-19. The coronavirus from a pangolin
could possibly have been transmitted to a human, either directly or through an
intermediary host such as civets or ferrets.
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