Thanks to new data, today the origin of the pandemic is clearer

Thanks to new data, today the origin of the pandemic is clearer

A report published by the Atlantic and anticipated by the WHO makes the scientific community lean more and more towards the hypothesis of a zoonosis originating from the Wuhan market. But to understand its significance, one must sort out what has been discovered so far

About a week ago, it was leaked to the press, and advanced to WHO, a new data useful for tracing the possible origin of the Sars-Cov-2 pandemic: the isolation of abundant genetic material of a particular species, the raccoon dog, in the same samples that tested strongly positive for the virus, coming from cages and other structures of the famous market. Now, in order to appreciate the difficulty, as well as the real significance, of these new data, it is advisable to reconstruct from the beginning the history of the circumstantial evidence obtained so far, regarding the origin of the epidemic starting from live animals sold in the Huanan market in Wuhan.

Since 2020, it has been known that some species of carnivores, including the raccoon dog, easily become infected and transmit the Sars-Cov-2 virus. This result was expectedbecause that species is known to be a vehicle for numerous infections, even dangerous to humans, including Sars-1: not surprisingly, an in-depth study conducted in 2021 confirmed what was already known about it. Until June 2021, Chinese authorities had denied what everyone knewor that live animals were sold in the Huanan market, and animals capable of carrying Sars-Cov-2 in particular, arousing the wrath of the international scientific community when, a year and a half after the start of the pandemic, scientists Chinese published exactly the opposite, namely that in reality these animals were sold alive at the Wuhan market until the beginning of the pandemic.

Subsequently, it was shown that in thousands of animals, including raccoon dogs, sampled between 2017 and 2021 around Wuhan, there were viruses of all kinds, and jumps of species, even starting from bats, were numerous; shortly thereafter, tissue from animals sold for food in Wuhan and bats from that city, sampled in January 2020, were found to contain numerous viruses, including several coronaviruses of various types. In July 2022, a first molecular epidemiology study was therefore published, obtained by examining the samples of the first positive patients at the outbreak of the pandemic: the researchers, examining the genomic diversity of the virus at the beginning of its spread, found two lineages originating during the beginning of the pandemic, before the virus began to spread and change exponentially. Lineage B was found in the genetic sequences of people who were directly associated with the marketplace, while lineage A was found in the genetic sequences of people who lived near it. This first data, i.e the simultaneous presence since the beginning of the pandemic in Wuhan of two different viral lineagesseems to document a multiple spill-over, starting from several different animals.

In a second independent study, published at the same time, the researchers mapped the data from early infections in Wuhan and mapped it by neighborhood. Thus they discovered that the highest density of cases in Wuhan was concentrated around the market, not only among workers or people who had direct ties to the people who worked there; but, far more important, they found that the people most affected in the pandemic trigger were very specifically associated with frequenting immediately prior to symptoms those parts of the market where wild animals were sold, including raccoon dogs and other SARS-susceptible animals. CoV-2. Now, the data anticipated on March 18 by the service of "the Atlantic", confirmed by the Chinese government, have added a further element: contradicting their own previous data, in the samples taken from the Huanan market around the beginning of the epidemic, for example from some cages used to keep animals alive, viral RNA has now been found to have a strong association with their DNA, and especially of raccoon dogs.

It is as if, at the scene of a crime, we find the DNA of a perpetrator and his victim in association: it is a rather strong link between pathogen and vector, a stronger link than those that have emerged so far. Although, up to this point, except in cases where susceptible animals had been experimentally infected, it has never been found in Wuhan, and in the Huanan market, the genome of the virus in animal tissues, the association between cages, DNA of susceptible animals (known to be imported into Wuhan from farms also located near the famous bat crowns, and known to be infectable by bats) and viruses is robust enough. This is certainly, once again, circumstantial evidence, albeit stronger than the previous ones: it does not exclude, for example, that human beings infected raccoon dogs in the early days of the pandemic. For this reason, those who believe that the problem of the origin of the pandemic has now been definitively resolved and that the mechanism that led to its triggering has been identified is mistaken; and yet the bulk of the evidence we have today, and the bulk of the scientific community, leans ever more decisively towards the hypothesis of a zoonosis that started from the Wuhan market.

Net of bizarre hypotheses based on erroneous analyzes of the viral genome sequence, aimed at demonstrating the laboratory construction of the virus (for which other elements of fact would be needed), those who support alternative hypotheses, including a minority of American government agencies, claims to have decisive evidence capable of being compatible with the published facts, but of tipping the balance in favor of the theory of an accidental leak from a Wuhan lab. However, until such evidence is produced, and net of the very numerous obstacles placed so far by the Chinese to clarify what really happened, the evidence is decidedly in favor of a contagion that started from the cages of the Huanan market; without therefore flaunting who knows what definitive data, it is good to consider that, also in the light of the very latest data, the problem of zoonoses due to the excessive contact between human populations and wild animals is an urgency that requires the immediate reconsideration of all breeding, sale and domestic keeping of at least certain species.



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