Black-footed ferrets are carnivorous mammals that live in North America, mostly in the U.S. Considered an endangered species, the critters nearly went extinct around 1980.

"We have about 300 ferrets in captivity," said Pete Gober, the ferret recovery coordinator for the U.S. Fish and Wildlife Service. The Black-Footed Ferret Conservation in Colorado where he works runs a captive breeding program for the animals. 

"They're a highly specialized predator that relies on prairie dogs for both food and the burrow system for protection from their own predators like coyotes and golden eagles," Gober said.

When prairie dog populations were decimated by poisoning, farming operations and sylvatic plague, black-footed ferret numbers also plummeted, prompting aggressive recovery efforts. Now, there's a new worry for folks like Gober: COVID-19. 

"Definition of history is one damn thing after another and COVID seems to be that you know," he said.

Outbreaks of the disease in minks, raised for their fur in the U.S. and Europe, set off alarm bells last year.

"They're all in the weasel family and since mink were susceptible to COVID-19, we were concerned that black-footed ferrets would be too," Gober said. "We really kind of got rattled."

Ferret managers decided to inoculate them with a COVID-19 vaccine. The drug was developed by the U.S. Geological Survey's National Wildlife Health Center and administered to two-thirds of Colorado's captive ferrets. The vaccine has shown some efficacy. No ferrets have contracted COVID-19 so far.

"I think it's wonderful that we were able to as a scientific community rapidly deploy vaccines for this species," said Anna Fagre, a veterinary microbiologist and Colorado State University post-doctorate fellow. 

She said the fact that black-footed ferrets have been prone to previous coronavirus infections meant:

"We should keep an eye on ferrets and ferrets were a species that was susceptible to SARS so it might become an issue for those animals," Fagre said.

In mink populations, this virus is believed to have spread from human handlers, mutated and then passed back to humans. Millions of the animals were culled after the outbreaks. The Colorado center moved its ferrets into smaller groups and staggered worker shifts to minimize the threat locally.

"We're playing the statistical probabilities on trying to limit any transmission that might be there," Gober said.

Black-footed ferrets have developed a following over the years. The COVID-19 vaccine, and others that may soon be commercially available, are aimed at maintaining their reintroduction into the wild and keeping this very vulnerable species alive.

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