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COVID-19 epidemic caused by natural quirk of fate

– March 25, 2020

The current coronavirus SARS-CoV-2 evolved naturally. A group of scientists from the United States, Australia and Great Britain have studied the genetic material and compared this with various coronaviruses that have led to previous human contagions. In the scientific journal Nature Medicine, they wrote: 'Our analyses clearly show that SARS-CoV-2 is not a laboratory construct or a purposefully manipulated virus.' This study has laid the conspiracy theories and fake news about the new coronavirus to rest, including the theory that the virus is man-made.

Corona concepts

We'll start off with a quick lesson in coronavirus jargon. The term 'coronavirus' is a collective term for a large family of viruses. Coronaviruses resemble spheres with spikes on their surface. The sphere contains RNA, the recipe for constructing more viruses. Coronaviruses cause diseases in animals. Sometimes viruses will change in a way that they also make humans sick. SARS-CoV was the first coronavirus to have a serious impact on humans. In 2003, the virus caused an epidemic of a disease called SARS (Severe Acute Respiratory Syndrome). The virus we are currently dealing with is called SARS-CoV-2. This virus causes the disease called COVID-19 (Corona Virus Disease 2019).

Additional building

block in the blueprint In order to trace the origin of the SARS-CoV-2 virus, the researchers took a close look at the RNA of the virus. They found an entire new 'chapter' in the RNA, which does not exist in related coronaviruses: a mutation. Although this is a very normal occurrence in nature, it is extremely difficult to add such a piece of viral RNA in the lab. Even if the most modern molecular techniques in virus research are used, it is still only possible to very slightly adapt an existing virus. The change in the SARS-CoV-2 virus is so substantial that it could not have been designed by humans.

Effectively entering cells

Researchers found another strong clue when they studied the piece of RNA that codes the 'tentacles' of the virus. These are made from proteins that bind very specifically to the exterior of a human cell. The researchers discovered that the SARS-CoV-2 tentacle does indeed fit very well on human cells. However, computer simulations also showed that this could be even more specific with just a few slight modifications. Anyone designing a virus would never choose the second-best design.

Original article from Nature Medicine: Andersen, K.G., Rambaut, A., Lipkin, W.I. et al. The proximal origin of SARS-CoV-2. Nat Med (2020). https://doi.org/10.1038/s41591-020-0820-9

   

Fehr A.R., Perlman S. (2015) Coronaviruses: An Overview of Their Replication and Pathogenesis. In: Maier H., Bickerton E., Britton P. (eds) Coronaviruses. Methods in Molecular Biology, vol 1282. Humana Press, New York, NY. https://doi.org/10.1007/978-1-4939-2438-7_1

   

WHO Q & A on coronaviruses (COVID-19), seen on 24-3-2020. https://www.who.int/news-room/q-a-detail/q-a-coronaviruses