SARS-CoV-2 is uniquely adapted to infect humans

The novel coronavirus pandemic has generated much debate about its origin, some suggesting that it may have grown in the laboratory. However, previous studies have stated that the virus is a zoonotic disease in nature, which means that the virus has jumped from wild animals and has found a route of transmission to humans.

Now, researchers claim that the virus has uniquely adapted to infect humans, suggesting that the theory of viruses growing in the laboratory should not be completely ruled out.

What is a zoonosis?

Zoonosis or zoonosis is an infection caused by harmful pathogens such as bacteria, viruses, fungi, and parasites that spread from animals to humans. Many zoonotic diseases are common, Coronavirus..

Chengdu / China-February 2020: Security guard with face mask outside the local wet market. Image credit: Amar Shrestha / Shutterstock

Animal pathogens spread to human populations through direct contact with infected animal body fluids, migration to areas where animals live, biting insects such as mosquitoes and fleas, and eating contaminated food. ..

Today, the world is working on a new type of coronavirus, the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) that causes coronavirus disease (COVID-19). Although the exact origin of the virus has not yet been confirmed, bats as a known reservoir of coronavirus are at the top of the “most likely” list.

Bird market in Kowloon, Hong Kong. Image credit: Christian Mueller / Shutterstock

The new coronavirus causes disease in more than 5.4 million people and causes more than 345,000 deaths worldwide.

Uniquely adapted to infect humans

In a new study available at Preprint server arXiv* This has not been peer-reviewed, but researchers have pointed to a number of reasons why the virus has been so well adapted to humans. For example, convergent evolution after exposure to human cells, exposure to human cells at a very early stage of the pandemic, mutations that combine genes from two rare species. All this raises the question of whether the origin of SARS-CoV-2 is natural or whether it occurs in the laboratory.

“The devastating effects of the COVID-19 pandemic caused by SARS coronavirus 2 (SARS-CoV-2), whether it is the origin of the virus, the mechanism of zoonotic transmission from exotic animals to humans, or companion animals, But when used for commercial purposes, it can serve as a reservoir for infections, which is why variability in susceptibility varies across species, “the researchers wrote.

Professor Nikolai Petrovsky of the Flinders University School of Medicine, who has spent decades developing vaccines against influenza, SARS in animals, and Ebola, said the results of this study were very unusual and the virus was born from laboratory experiments. ..

But at this point, it is impossible to deny the theory that the virus was created in cell culture experiments, he said.

The results of this study show that the virus was designed specifically for humans, and whether it happened naturally or by accident, has not yet been investigated.

He added that the virus was not common for typical animal-to-human transmission, as it can penetrate the human body quickly. Other pathogens of the past that have jumped from animals to humans usually become stronger as they adapt to new hosts, but SARS-CoV-2 appears to be fully adapted to human infections.

SARS-CoV-2 spike protein

Using an in silico structural homology modeling approach, the team characterized a novel coronavirus spike protein and predicted high affinity binding to the human angiotensin converting enzyme 2 (ACE2) receptor.

SARS-CoV-2 virus that binds to ACE-2 receptor in human cells, early stage of COVID-19 infection, conceptual 3D illustration credit: Kateryna Kon / Shutterstock

Traditional lab-based methods are typically used, but results may take some time. On the other hand, in silico modeling techniques may generate information about emerging pathogens more quickly and may provide insights into their behavioral and physical effects.

SARS-CoV-2 virus, which binds to ACE-2 receptor in human cells, early stage of COVID-19 infection, conceptual 3D illustration credit: Kateryna Kon / Shutterstock

The team found that the SARS-CoV-2 spike protein has the highest overall binding energy for human ACE2 and is more important than all other test species, including the virus source bat. .. In addition, the team revealed that SARS-CoV-2 is a highly adapted human pathogen. Pangolin was another claimed animal source of the outbreak in Wuhan, China, and then had the highest binding affinity.

“Overall, the data show that SARS-CoV-2 is uniquely tuned to infect humans, whether it was a rare, spontaneous occurrence, or its origin in other ways. We’re asking if it’s there, ”the team concludes.

Researchers added that given the severity of the ongoing COVID-19 pandemic, every effort must be made to identify the cause of the coronavirus. To establish whether the coronavirus disease was caused by a natural accidental occurrence of a bat-derived, jumping to humans through an intermediate animal host, or whether COVID-19 has other origins. Is essential.

Grown in the laboratory

With the advent of the new coronavirus pandemic, many theories have emerged about its origin. One question that was posed a few months ago was whether the virus came from Wuhan’s lab, a level 4 biosafety lab that studies animal coronaviruses.

According to Wang Yanyi, the director of the institute, the Wuhan Virology Institute has long been in isolation for several coronaviruses from bats, and has since

But the director denies the virus came from the lab.

“When I looked into the pathogens in my sample, I found that they contained a new coronavirus. I didn’t know anything before that, and I met, investigated, and kept the virus. There was no”

“Actually, like everyone else, I didn’t even know the virus existed, so how would we leak from the lab when we didn’t have one?” She says. It was.

Meanwhile, Chinese Foreign Minister Wang Yi said rumor that the virus was artificial was put there to blame China. However, countries can accept international participation and identify the source of SARS-CoV-2 as long as there is no political interference in the investigation.

Did SARS-CoV-2 adapt to humans long before the index case?

another Recent studies from Canada And the United States suggests that Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) may already be adapted to human transmission when it emerges in late 2019. .. In other words, the population of precursor SARS-CoV-2 proficients may be protracted. Due to human infection and the re-emergence of coronavirus disease (COVID-19).

*Important Notices

arXiv.org publishes preliminary scientific reports that have not been peer-reviewed and should not be considered conclusive and should guide clinical practice / health-related behaviors or as established information. Should not be treated.