The novel coronavirus appeared to be circulating undetected for at least two months before the first human cases of COVID-19 were reported in Wuhan, China in late December 2019, according to a study.
The research, published in the journal Science, used molecular isolation devices and epidemiological simulations until the virus appeared as early as October 2019.
The team, including researchers from the University of California San Diego in the U.S., notes that their simulations suggest that more than three-quarters of the mutating virus dies naturally. of the time without causing disease.
“Our study was designed to answer the question of how long SARS-CoV-2 could last in China before it was discovered,” said study lead author Joel O Wertheim, associate professor at UC San Diego School of Medicine.
“To answer this question, we put together three important pieces of information: a detailed understanding of how SARS-CoV-2 spread in Wuhan before it was locked out, the genetic diversity of the virus in China and reports of the earliest cases of COVID-19 in China, “Wertheim said.
By combining these different lines of evidence, the researchers were able to put an end to mid-October 2019 for when SARS-CoV-2 began circulating in the Hubei region.
Outbreaks of COVID-19 were first reported in late December 2019 in Wuhan, located in Hubei region of central China.
The researchers used molecular clock evolutionary analyzes to try to find out when the first, or index, of SARS-CoV-2 occurred.
A “molecular clock” is a term for an approach that uses the rate of change of genes to elicit when two or more life forms dive – in this case , when there was a common ancestor of all variants of SARS-CoV-2, measured in this study as early as mid-November 2019.
Molecular coagulation of the most recent common ancestor is often considered to be related to an index case of an emerging disease.
“The index issue may be premature before the common ancestor – the first case of this behavior may have occurred days, weeks or even several months before the estimated common ancestor , “said study co – author Michael Worobey, a professor at the University of Arizona.
“Determining the length of that‘ phylogenetic meltdown ’was at the heart of our study,” Worobey said.
Based on this work, the researchers estimate that the median number of people with SARS-CoV-2 infection in China was less than one to November 4, 2019.
Thirteen days later, it was four individuals, and just nine on December 1, 2019, they said.
The first hospitals in Wuhan occurred with a condition that later became known as COVID-19 in mid-December.
The researchers used several diagnostic tools to model how the SARS-CoV-2 virus could have been transmitted in the early and early days of the pandemic during its transmission. virtually unknown.
These tools included epidemic simulations based on the known biology of the virus, such as transmission and other factors.
In only 29.7 percent of these samples was the virus capable of causing autoimmune diseases.
In the other 70.3 percent, very few people contracted the virus before it died. The average epilepsy ended just eight days after the index case.
“We saw that more than two-thirds of the pandemics we tried to simulate have become extinct. That means if we could go back in time and do 2019 again. one hundred times, two out of three times, COVID-19 would have gone on its own without avoiding a pandemic, Wertheim noted.
“This finding supports the notion that humans are constantly bombarded with zoonotic pathogens,” he said.
(Only the headline and image of this report may have been reworked by Industry Status staff; the rest of the content is automatically generated from syndicated feeds.)