THE coronavirus found its way to the U.S. from two different continents — with the majority of cases in New York coming from Europe, not Asia, according to new studies.
Researchers studied genomes, or an organism's complete set of DNA, from New Yorkers starting in mid-March, and found the virus had been circulating before testing even began.
The virus is believed to have arrived in the U.S. before Washington state — where the virus was first detected in the country — confirmed its first case.
Harm van Bakel, a geneticist at Icahn School of Medicine at Mount Sinai who co-wrote a study, told The New York Times: “The majority is clearly European.”
Another team, at the NYU Grossman School of Medicine, studied different cases, but found similar results also looking at genomes from New Yorkers.
President Donald Trump announced on January 31 that his administration would not let people who had been to China in the past two weeks into the U.S.
“We’re the ones that gave the great response, and we’re the ones that kept China out of here,” he told reporters in March.
“If I didn’t do that early call on China — and nobody wanted that to happen. Everybody thought it was just unnecessary to do it.”
But it wasn’t for weeks that many European countries began to lockdown their cities and Trump didn’t announce he was banning travel to and from dozens of European countries until March 11.
But Dr. Adriana Heguy, a member of the NYU team, said their research shows that the U.S. could have contained the coronavirus outbreak if officials didn’t limit testing to just those coming in from China or certain countries.
She told the Times: “People were just oblivious.”
Heguy said their research found some viruses among New York were “unique mutations” that they didn’t find anywhere else.
“That’s when you know you’ve had a silent transmission for a while,” she said, adding they believe the virus began circulating in the Empire State months ago.
Ana Silvia Gonzalez-Reiche, a member of the Mount Sinai team, told the newspaper they
started sequencing the genomes of patients who were visiting their hospital.
They found the earliest cases of the virus identified in New York were not linked to later ones, but “two weeks later, we start seeing viruses related to each other.”
She said the viruses were practically identical to those found in Europe, but they can’t determine what flight or when it got to the U.S.
Mount Sinai researchers wrote the virus came through during “a period of untracked global transmission between late January to mid-February.”
People on the United States’ West Coast were affected by the same strain of the coronavirus that was seen in Wuhan, China, where the outbreak first began.
Dr. Trevor Bedford, an associate professor at the Fred Hutchinson Cancer Research Center and the University of Washington, said he and his colleagues sequenced coronavirus genomes — and got a better view of how Washington’s outbreak started.
Bedford told the Times: “I’m quite confident that it was not spreading in December in the United States. … There may have been a couple other introductions in January that didn’t take off in the same way.”
Scientists at Cambridge University found in a recent study that there are three distinct strains of the coronavirus that make up most of the world’s cases.
They sampled virus genomes to find three distinct “variants” of COVID-19.
Researchers said one of the strains, the “original human virus genome,” that was one discovered in bats was found in Wuhan, but was not the city’s predominant virus strain.
Types of that strain were found “ in Americans reported to have lived in Wuhan,” and were found in people from the U.S. and Australia.
Another major virus strain found in Wuhan was prevalent in people from East Asia, but that strain “didn’t travel much beyond the region without further mutations – implying a ‘founder event’ in Wuhan, or ‘resistance’ against this type of COVID-19 outside East Asia.”
The other strain is the “major European type, found in early patients from France, Italy, Sweden and England,” and was also seen in Singapore, Hong Kong and South Korea.
The first strain was “most closely related to the virus found in both bats and pangolins, is described as ‘the root of the outbreak’ by researchers.”
The second strain was derived from the first, but were separated by two mutations. The third strain is a “daughter” from the second strain.
“The viral network we have detailed is a snapshot of the early stages of an epidemic, before the evolutionary paths of COVID-19 become obscured by vast numbers of mutations,” geneticist Dr. Peter Forster, lead author from the University of Cambridge, said.
Forster says their study suggests the first coronavirus infection and spread from person-to-person happened between mid-September and early December.
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