Why carnivores host diseases that jump to humans

IN NOVEMBER 2020, at the height of the second covid-19 wave in Europe, the Danish government revealed that a new strain of the virus had been found in farmed mink. Officials worried that the new strain could become widespread in humans, where it might prove deadlier or more resistant to vaccines. For Clare Bryant, a veterinary scientist at the University of Cambridge, this was exactly what she feared might happen. “I thought holy moly, there you go,” she says.At the time, she and her team were investigating the biology of , an order of meat-eating mammals that includes cats, dogs, bears and mink, among others. is a potent source of “zoonotic” diseases—those that have jumped to humans from their original animal hosts. Almost half of its members carry one or more unique zoonotic pathogens. Biologists have long wondered why that should be. Dr Bryant’s paper, published in , suggests an answer.