A file photo of a coronavirus test. Photograph:( AFP )
The Chinese government, some scientists are desperately trying to convince the public that COVID-19 is a naturally-occurring disease, which was transmitted from animals to humans in the Wuhan Seafood Market.
A recently published scientific article states:
“Due to the broad-spectrum of research conducted over almost 20 years on bat SARS-CoV [severe acute respiratory syndrome coronaviruses] justified by their potential to spill over from animal to human, a possible synthetic origin by laboratory engineering of SARS-CoV-2 [COVID-19] is a reasonable hypothesis.”
China would like that hypothesis erased from the public consciousness.
The Chinese government, the media and some scientists are desperately trying to convince the public that COVID-19 is a naturally-occurring disease, which was transmitted from animals to humans in the Wuhan Seafood Market.
If COVID-19 leaked from a laboratory, the political and economic consequences for China are enormous.
If it was man-made and leaked from a laboratory, the implications are too grim for many to imagine.
The argument that COVID-19 is naturally-occurring is based nearly entirely on a single, but widely-cited Nature Medicine article entitled “The Proximal Origin of SAR-CoV-2.”
That conclusion stems primarily from a structural analysis comparing COVID-19 with bat and pangolin (scaly anteater) coronaviruses suggesting a natural evolutionary process in which COVID-19 mutated in an animal population and acquired the ability to infect humans.
Such a scenario does occur and it appears to be the origin of a number of animal-borne coronavirus infections in humans.
Based on the evidence provided in the much-cited Nature Medicine article, however, that conclusion is not obvious.
Although COVID-19 bears a striking structural similarity to the bat coronavirus RaTG13, the critical receptor binding domain, which initiates attachment to human cells, is closer to pangolins.
It is highly unlikely that the bat RaTG13 coronavirus and the pangolin coronavirus combined naturally through a process called reassortment because it would require simultaneous infection of the two viruses in the same animal cell.
It could, however, have been accomplished in a laboratory.
As the recently-published scientific article notes, a new “chimeric” or combined RaTG13-pangolin coronavirus strain could have been created through an artificial recombinant event, using well-established bioengineering methods.
Another possible indication of genetic manipulation is the presence of a furin polybasic cleavage site in COVID-19 as represented by the PRRA amino acid insertion, which does not exist in any of the bat or pangolin close relatives and is completely “out of frame” compared to the bat RaTG13 and pangolin sequences.
Perhaps not coincidentally, the furin polybasic cleavage site in COVID-19 occurs in the precise location known to enhance pathogenicity and transmissibility in viruses.
Methods for the insertion of a polybasic cleavage site in infectious bronchitis coronavirus have been described by Chinese scientists and that artificial genetic alteration resulted in increased pathogenicity.
In parallel, animal models for the addition of structures important to the function of coronaviruses, called O-linked glycans, have been used by Chinese scientists at the Chongqing Military Medical University, as well as animal models to specifically select for the human angiotensin-converting enzyme-2 receptor, the entry step for COVID-19 infection.
There is no doubt that China has the knowledge and technology to have created COVID-19. Whether that actually was done is yet to be determined and should be undergoing vigorous scientific investigation.
(Disclaimer: The opinions expressed above are the personal views of the author and do not reflect the views of ZMCL)