The Case Is Building That COVID-19 Had a Lab Origin
If the public has learned a lesson from the COVID-19 pandemic it is that science does not generate certainty. Do homemade face masks work? What is the death rate of COVID-19? How accurate are the tests? How many people have no symptoms? And so on. Practically the lone undisputed assertion made so far is that all the nearest known genetic relatives of its cause, the Sars-CoV-2 virus, are found in horseshoe bats (Zhou et al., 2020). Therefore, the likely viral reservoir was a bat.
However, most of these ancestor-like bat coronaviruses cannot infect humans (Ge et al., 2013). In consequence, from its beginning, a key question hanging over the pandemic has been: How did a bat RNA virus evolve into a human pathogen that is both virulent and deadly?
The answer almost universally seized upon is that there was an intermediate species. Some animal, perhaps a snake, perhaps a palm civet, perhaps a pangolin, served as a temporary host. This bridging animal would probably have had an ACE2 cellular receptor (the molecule which allows cellular entry of the virus) intermediate in protein sequence (or at least structure) between the bat and the human one (Wan et al., 2020).
In the press and in the scientific literature, scenarios by which this natural zoonotic transfer might have occurred have been endlessly mulled. Most were fuelled by early findings that many of the earliest COVID-19 cases seem to have occurred in and around Wuhan’s Huanan live animal market. [The latest data are that 14 of the 41 earliest cases, including the first, had no connection to the animal market (Huang et al. 2020)].
Since the two previous coronavirus near-pandemics of SARS (2002-3) and MERS (2012) both probably came from bats and both are thought (but not proven) to have transitioned to humans via intermediate animals (civets and dromedaries respectively), a natural zoonotic pathway is a reasonable first assumption (Andersen et al., 2020).
The idea, as it applied to the original (2002) SARS outbreak, is that the original bat virus infected a civet. The virus then evolved briefly in this animal species, but not enough to cause a civet pandemic, and then was picked up by a human before it died out in civets. In this first human (patient zero) the virus survived, perhaps only barely, but was passed on, marking the first case of human to human transmission. As it was successively passed on in its first few human hosts the virus rapidly evolved, adapting to better infect its new hosts. After a few such tentative transmissions the pandemic proper began.
David Adams
Article URL : https://www.zerohedge.com/health/two-doctors-explain-why-covid-19-was-likely-lab-experiment?