Leap Of COVID-19 From Animals To Humans. A Novel Discovery That Can Change The Rules.

Scientists have identified two new coronaviruses in humans, although neither was proven to cause illness or spread to other people. One study identified pigs as the animal host of one virus, and another study found that a coronavirus had likely stemmed from dogs, the first time a canine coronavirus has been shown to infect humans. 

“This research clearly shows that more studies are desperately needed to evaluate critical questions regarding the frequency of cross-species [coronavirus] transmission and potential for human-to-human spread,” Ralph Baric, a virologist at the University of North Carolina, Chapel Hill, who was not involved in either study, tells Science.

 

The dog study, published May 20 in Clinical Infectious Disease, stemmed from a question Gregory Gray, an infectious disease epidemiologist at Duke University, had early in the pandemic, reports NPR. He wondered whether there were other coronaviruses already infecting people that might one day spark outbreaks, and he asked his graduate student, coauthor Leshan Xiu, to design a test that would detect not just SARS-CoV-2, but previously unknown coronaviruses as well.

 

Gray sent samples of the virus to Anastasia Vlasova, an expert in animal coronaviruses at the Ohio State University, and she found that the virus was actually a chimera—portions of its genome matched a feline coronavirus, while another part was similar to a porcine coronavirus. But the majority of its genome was most similar to two coronaviruses previously isolated from dogs, and she was able to grow the virus in canine cell cultures. “Canine coronaviruses were not thought to be transmitted to people,” Vlasova tells NPR. “It’s never been reported before.”