WHILE THE HUMAN TALLY of COVID-19 cases has risen, animal cases have remained novelties. As this issue of National Geographic went to press, you could count the affected species on one hand: lions, tigers, domestic cats, dogs, mink. The pets contracted the virus from their owners; the big cats, likely from an asymptomatic caregiver; and the mink, likely from fur farm workers or possibly other infected animals.
The virus is zoonotic—originating with animals—but causes a fundamentally human disease, says virologist Diego Diel of Cornell University’s Animal Health Diagnostic Center. If the virus that humans are spreading were a significant threat to animal health, he says, we’d know by now.
Beyond that conclusion is a sea of unknowns. There’s no evidence that domesticated animals can pass the virus to humans, but…
