Things change fast. Even just a few months ago, most of us who aren’t virologists, microbiologists, or veterinarians had probably never heard of coronaviruses. Yet last week, the Centers for Disease Control and Prevention advised that it’s not a question of whether the outbreak of a coronavirus known as SARS-CoV-2 (and its associated disease, COVID-19) would spread in U.S. communities, but when—and we should be prepared for potential disruptions in our daily lives as a result.
But this change didn’t come out of nowhere. Even though this particular viral strain only recently emerged as a new human disease, coronaviruses have been around for a very long time. Likewise, Susan Weiss, a professor of microbiology at the Perelman School of Medicine, is newly quite busy launching research projects to help respond to the threat of the novel coronavirus—but coronaviruses generally have been a major focus of her research for four decades.
Coronaviruses first became better known among non-scientists in early 2003 thanks to the virus family’s first famous human disease: Severe Acute Respiratory Syndrome (SARS). The agent, called SARS-CoV, started to cause illness in southern China before spreading to North America, South America, Europe, and Asia. “It was really scary because there was a high mortality rate, but compared to what’s going on now, it was fairly contained and small,” Weiss says. Ultimately SARS dissipated within about eight months. Since 2004 there have been no more known cases. But SARS was a warning shot—more viruses like it could be out there, on the verge of transforming into strains that cause serious human illness. Based on analyses of the SARS virus and searches for related genetic sequences in the environment where it emerged, scientists determined that the human virus evolved from a bat coronavirus that infected a civet, from which it mutated again and jumped to humans.
“After SARS, people started looking for human coronaviruses, and two others were identified,” Weiss says. These new strains caused some more severe symptoms than a typical cold but were still rarely fatal.
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