To minimize the risk of exposing animals to COVID, the men are fully vaccinated and boosted and get tested frequently.
The day after testing the bear, Isaac packed their samples to send to Aliota’s lab in Saint Paul. The veterinary and biomedical researcher hopes to learn not just which animals are getting infected but also whether certain animals are acting as “bridge species” to bring it to others. Testing may later be expanded to red foxes and racoons.
It’s also possible the virus hasn’t reached this remote location — yet. Since it’s already circulating in the wilderness of Minnesota and nearby states, Aliota said it’s only a matter of time.
looking for mutants
Close contact between humans and animals has allowed the virus to overcome built-in barriers to spread between species.
To infect any living thing, the virus must get into its cells, which isn’t always easy. Virology expert David O’Connor likens the process to opening a “lock” with the virus’ spike protein “key.”
“Different species have different-looking locks, and some of those locks are not going to be pickable by the key,” the University of Wisconsin-Madison scientist said.
But other locks are similar enough for the virus to enter an animal’s cells and make copies of itself. As it does, it can randomly mutate and still have a key that fits in the human lock. That allows it to leap back to humans through close contact with live animals, scientists believe.
Although spillback is rare, it only takes one person to bring a mutated virus into the realm of humans.
Some think the highly mutated omicron variant emerged from an animal rather than an immune-compromised human, as many believe. Virologist Marc Johnson of the University of Missouri is one of them, and now sees animals as “a potential source of pi,” the Greek letter that may be used to designate the next dangerous coronavirus variant.
Johnson and his colleagues found strange coronavirus lineages in New York City sewage with mutations rarely seen elsewhere, which he believes came from animals, perhaps rodents.
What scientists are most concerned about is that current or future variants could establish themselves and multiply widely within a reservoir species.
One possibility: white-tailed deer. Scientists found the coronavirus in a third of deer sampled in Iowa between September 2020 and January 2021. Others found COVID-19 antibodies in a third of deer tested in Illinois, Michigan, New York and Pennsylvania. Infected deer generally have no symptoms. Testing in many other wild species has been limited or absent.
“It’s possible that the virus is already perhaps circulating in multiple animals,” said virology expert Suresh Kuchipudi of Pennsylvania State University, an author of the Iowa deer study. If unmonitored, the virus could leave people “completely blindsided,” he said.
Can it be stopped?
Ultimately, experts say the only way to stop viruses from jumping back and forth between animals and humans — extending this pandemic or sparking a new one — is to tackle big problems like habitat destruction and illegal wildlife sales.
“We are encroaching on animal habitats like we have never before in history,” Aliota said. “Spillover events from wild animals into humans are, unfortunately I think, going to increase in both frequency and scope.”
To combat that threat, three international organizations — the United Nations Food and Agriculture Organization, the World Organization for Animal Health and the World Health Organization — are urging countries to make COVID surveillance in animals a priority.
In Grand Portage, Aliota’s collaborators continue to do their part by testing as many animals as they can catch.
With icy Lake Superior sparkling through the evergreens, Isaac slipped his hand beneath the netting of a deer trap. A colleague straddling the animal lifted its head off the snowy ground so that Isaac could swab its nostrils.
The young buck briefly lurched his head forward, but kept still long enough for Isaac to get what he needed.
“Nicely done,” his colleague said as Isaac put the sample into a vial.
When they were finished, they gently lifted the trap to let the deer go. It bounded into the vast forest without looking back, disappearing into the snowy shadows.