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And now for the Back Story on …
A rewritten U.S. timeline for the coronavirus
News that a person who died in Santa Clara County, Calif., on Feb. 6 had the coronavirus has raised questions about the timeline of the U.S. outbreak, which is by far the world’s largest. To get a scientific view of the implications, we spoke to Carl Zimmer, a science reporter, Times columnist and the author of the book “A Planet of Viruses.”
What do we know about the timing of the virus’s arrival in the U.S.?
The virus itself jumped from bats into humans in Asia, most likely China. Then there’s the outbreak in Wuhan, picking up speed in December. Then it’s in Europe, probably in early January.
Studies of samples of virus from New York showed that the vast majority belonged to lineages introduced from Europe, and probably arrived early to mid-February. You can see this from minor but telltale mutations in their genes that act like a signature. What the New York viruses are most similar to is not the viruses in Italy, but viruses in England, in France, in Belgium. It looks like a lot of viruses were moving around in Europe, and some were brought to the United States.
The evidence from California indicates it was arriving there by early or mid-January.
Could the virus have been circulating in California even earlier?
Scientists don’t believe Covid was raging in California in November. Looking at virus genes, they can see it was just getting started around then in Wuhan. They don’t see the kind of hospitalizations in California you’d see if it was taking off. We know what it’s like when Covid-19 takes off, and it was not happening in November.
What are you looking for next?
In the autopsy for the Feb. 6 case, all they needed to find to confirm that this person had Covid-19 was some fragments of the virus’s genes.
If you really want to know more, you need the whole genome — all the genetic material in the virus. Then, looking at the mutations, you can see where the virus came from, and you can start getting some guesses about how it got there.
But we’re dealing here with a deceased person. The virus in their remains is breaking down.
Still, it’s possible that scientists may be able to extract enough virus to put the genome back together. I’m hoping for that.
That’s it for this briefing. If you’re bored, try “flip the switch.” See you next time.
To Melissa Clark for the recipe, and to Theodore Kim and Jahaan Singh for the rest of the break from the news. Andrea Kannapell, the Briefings editor, wrote today’s Back Story. You can reach the team at firstname.lastname@example.org.
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