Luca Longo’s analysis of Sars-CoV-2 published in MIT Technology Review
The notorious Sars-CoV-2 virus that is terrorizing the entire planet by spreading the often lethal Covid-19 infection could be among humans since years. This is the conclusion reached by a multidisciplinary team of virologists, epidemiologists and other scientists from prestigious institutions in the United States, United Kingdom and Australia, coordinated by the Scripps Research Institute in California.
In the study “The proximal origin of SARS-CoV-2″, recently published in the well-known scientific journal Nature, Kristian G. Andersen, Andrew Rambaut, W. Ian Lipkin, Edward C. Holmes and Robert F. Garry have shown that this virus ” it cannot be the product of intentional manipulation “. In fact, the viral genomic sequence in which the instructions necessary to produce the characteristic spike proteins capable of binding with the receptors on the surface of human cells and allowing the virus to inject its own Rna into the cells are notably different from the sequences. corresponding genomics present in every known Sars-CoV-like coronavirus.
Excluding at this point the presumed artificial origin – and the consequent possibility of a potentially accidental or criminal release in the human population – there are only two possible scenarios to explain the appearance of Sars-CoV2 among humans.
The first plausible scenario assumes an evolution of the virus among animals – possibly following a recombination of different coronaviruses found in bats, pangolins or other species – and a subsequent zoonotic transfer: the final leap towards humans. This hypothesis could be deduced not only from the comparison of RNA sequences, but also from the possible connection between the first reported cases and the Wuhan food market. The authors show that Malaysian pangolins – illegally imported into Guangdong province – contain coronaviruses similar to the one currently in circulation. However, the zoonotic transfer theory has not yet been proven by animal studies. Effectively,
The second scenario assumes that the virus made the species leap towards man a long time ago, albeit in a decidedly less contagious and lethal version that would have had the opportunity to spread unnoticed among us, perhaps for whole years. This invisible spread would have allowed the virus to progressively acquire new genomic characteristics, to better adapt to its newly acquired human hosts and to differentiate into a series of slightly different varieties.
A similar secret spread and subsequent adaptations would have allowed the virus to achieve that last decisive mutation necessary to make the Covid-19 pandemic take off abruptly among us, causing an exponential growth in the number of cases – explain the scientists.
In full spread of Covid-19 – the authors conclude – discovering the origins of the pandemic and “understanding how an animal virus managed to overcome the boundaries between species to infect humans in such an effective way” will be a very useful tool. to obtain the information necessary to prevent the recurrence of similar dramatic events in the future.
Furthermore, the collection and analysis of further scientific evidence could allow epidemiologists to confirm one of two hypotheses about the origins of the virus to enable them to fight the pandemic more effectively. A better understanding of the virus’ spreading and transmissibility mechanisms could allow scientists and governments to mitigate – and ultimately bring under control – the course of the worst pandemic of the century.
(Translated from English by Lisa Ovi)
