Thursday, June 24, 2021

Lab leak theory of Covid-19


WIV image credit: Kyodo News via Getty
There is a huge debate these days about the origin of Covid-19/Corona/SARS-CoV-2; that this virus either has emerged from some zoonotic host in nature or it is bioengineered in some Virology lab. Before coming to any conclusion, it would be better to evaluate both possibilities in the light of available evidences. 

Possible spillover from nature: 
1. Most scientist believe that SARS-CoV-2 has a spillover from nature, because
bats are the known carrier for coronavirus. Horseshoe bat (Rhinolophus affinis) is commonly found in southern China. Genome of virus RATG13 found in this bat is 96 percent identical to the genome of SARS-CoV-2 causing Covid-19 in human.
2. This means that a closer link in between human and bat is missing for the difference of 4 percent genome.
3. Again the spillover from the lab is a remote possibility as lab engineered strain mostly cause small outbreaks. They are well documented and contained. 
4. Same covid-19 like pattern were found for emergence of infectious diseases causing pandemic in previous years; e.g. SARS coronavirus, influenza, Ebola, HIV etc. in other parts of the world.
5. 'WHO' too agreed for investigation in to pandemic's origin in depth (https://www.nature.com/articles/d41586-021-00375-7).

Lab leak theories are basically grounded on:
1. SARS-CoV-2's closest relative is still elusive to scientists.
2. Covid-19 first reported in Wuhan, is not a coincidence where WIV lab is researching on the same virus.
3. SARS-CoV-2 is spreading unusually quickly in humans, that points intention.
4. Furin cleavage site on virus protein spike, absent in it's closest relative. (But opponent to lab spillover theory believe it a convergent evolution for evolutionary advantage as virus adapting to the similar environment; as furin cleavage is also found on common cold viruses)
5. Original host of virus could not be found as yet.
6. CGG encoding for Amino Acid Arginine underlying a segment of furin cleavage site is preferred code for Arginine by humans, not viruses.
(https://nicholaswade.medium.com/origin-of-covid-following-the-clues-6f03564c038). (But opposite believer point the 3 percent of Arginine been coded by CGG code in SARS-CoV-2, citing example of Indian variant (B.1.617.2 or Delta) has mutations in nucleotides encoding it's furin cleavage site, making it more virulent variant.)

Spillover theory and word of politics: 
There are many voices echoed in favor of a fair enquiry in this matter. 
1. US President Joe Biden tasked US Intelligence community to find the origin of SARS-Co-2. 
2. Australia, EU, Japan were also in the same league in voicing their concern for a fair investigation. 
3. World leaders in G7 summit were also vocal in a statement issued to the media on June 13, 2021.
(https://www.thehindu.com/news/international/g7-leaders-discuss-wuhan-lab-leak-theory-behind-covid-19-pandemic/article34804805.ece)

It's true that:
The Wuhan Institute of Virology (WIV) in China's central Hubei province is located in the same city from where the first Covid-19 were reported, 
but there is no substantial evidence to prove the controversial spillover theory from lab as of yet.
A spillover from nature through a bat directly or indirectly seems most likely.

Latest:
Amidst all the suspicion of lab leak theory, the Chinese Academy of Sciences reportedly nominated the 'Wuhan Institute of Virology' for top science award in conducting 'the most comprehensive and systematic identification research on the aetiology of covid-19'.
(https://www.wionews.com/world/wuhan-lab-suspected-of-leaking-covid-19-nominated-for-top-science-award-in-china-393263)

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