Dogs have very strong noses.

“Their entire noses are just built for this kind of work,” says Dr. Cynthia Otto, director of the University of Pennsylvania School of Veterinary Medicine, who is leading a study to determine if dogs can in fact smell COVID-19. “The anatomy of their nose is set up to bring in a lot of air, and a lot of that goes right to the sensing area in their nasal passages.”

Once the scent gets there, dogs can remember it. “Dogs have many more receptors, and that allows them to process these odors really incredibly fast, and maintain this library of what this odor is, and what it means,” says Otto.

Otto’s team, who has previously used dogs in researching ovarian cancer, hopes they can develop a method for their dogs to be able to identify the novel coronavirus and alert their human trainers if someone is infected.

“Our study is trying to determine if there is an odor unique to COVID-19,” explains Otto. “And whether or not our dogs can help us differentiate samples from patients with COVID-19 and patients without COVID-19.”

If they are successful, dogs could be used to screen people at airports and workplaces, according to Otto. “We want to screen and say, ‘Yep, you’re good to go in,’ or, ‘You need to go back home and self-quarantine.’”

And while taking people’s temperatures can be helpful in those settings, there can be limitations in the accuracy, as COVID-19 is not the only reason why people could have a higher internal temperature. The training could even theoretically be applied to screen environments, according to Otto. “Say we had a nursing home that had COVID-19. We’ve gone through a deep clean; we can bring the dogs and say, ‘Is there any virus anywhere in this place?’”

The training process is conducted using a contraption called a “scent wheel,” in which samples are placed at the end of the arms of a stainless-steel carousel, and the dogs mark which sample is positive for COVID-19. If that stage is successful, which should be completed within a month, a longer process will be conducted from there, which will take months outside of a laboratory setting, training the dogs to find the odor on a person in a crowd.

The University of Pennsylvania School of Veterinary Medicine, located in Philadelphia, is temporarily closed due to the current health crisis, so the testing will be completed at a different, more contained facility in Maryland called Tactical Directional Canine Systems. Eight Labrador retrievers — of the golden, black, and chocolate variety — will participate in the study. Pat Nolan, who heads that facility, says the dogs are getting ready.

“They’ve shown to me an interest in the work, and they’re working hard at the project,” says Nolan, who is often training dogs in explosive detection.

Labradors are hunting dogs, so they have a long history of using their smell to help humans. Otto explains that they are a bit calmer and less intimidating than other dogs, like a German shepherd. And dogs in general are a bit more practical to partner with than other animals with great senses of smell. “We do know that there are other species, like sharks and grizzly bears, that have really good senses of smell,” says Otto, “but we would never imagine partnering with them on this kind of a project.”