Did Omicron come from mice?

By | February 12, 2022

Carolyn Kormann writes:

Last Thanksgiving, Rilu, an eleven-year-old snow leopard and father of seven, began sneezing and wheezing. Snow leopards are native to the Himalayas, but Rilu was born in a zoo in Oklahoma City, then moved to the Miller Park Zoo, in Illinois, in 2011, to form part of the Species Survival Plan—the zoos’ matchmaking effort to maintain a genetically diverse “insurance” population of endangered animals. A PCR test in early December confirmed that Rilu had Covid-19. He developed pneumonia and grew weaker, despite various attempts at treatment. On January 6th, he became the fifth captive snow leopard in the United States to die from Covid-19 complications within three months. There are roughly five thousand snow leopards in the wild, according to conservationists’ best estimates. Five leopards is, on a species level, equivalent to 7.9 million humans—or, nearly every person in New York City. (More than 5.7 million humans have died from Covid-19 globally, over two years.) The leopard deaths are, perhaps, the pandemic’s most tragic example of reverse zoonoses—when humans transmit a pathogen back to animals.

Because ancestral SARS-CoV-2 initially evolved in bats, then somehow found its way into humans, it is called a “zoonosis”—a disease that transmits from animals to us. Roughly seventy-five per cent of all emerging infectious diseases are zoonoses. But, as scientists learned in the early months of the pandemic, sars-CoV-2 transmits easily back to other species. It isn’t a picky virus, either. “I can’t think of any single zoonotic virus with an equivalently broad host range,” Barbara Han, a disease ecologist, told me. [Continue reading…]

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