Dogs Can Be Trained to Sniff Out COVID-19, Studies Suggest
“We are just in the first steps, but they are obviously very intriguing,” says one researcher who has been training dogs to detect the novel coronavirus.
Imagine this scenario: You walk into a hospital emergency room because you’re concerned about mild COVID-19 symptoms, but instead of being greeted by a nurse wielding a nasal swab, you look into the face of a gentle German shepherd. The dog gives you a sniff inspection, and with that, you have your test results.
Then envision dogs providing the same kind of sniff tests in other places: office lobbies, warehouse entrances, sports stadiums, malls, and concerts.
The use of trained dogs to detect the coronavirus may sound like science fiction, but it’s already happening. The Guardian recently reported that Finnish researchers launched a pilot study involving four COVID-19 dogs at the Helsinki airport. Arriving international passengers are asked to rub their skin with a special wipe, which is then placed in a beaker next to other containers of different control scents.
With a few sniffs, the dogs are able to identify infected passengers —?even those who are asymptomatic — with close to perfect accuracy.
Researchers around the world are working on similar projects. “We‘re just in the first steps, but they’re obviously very intriguing,” says Holger Volk, MD, a researcher at Germany’s University of Veterinary Medicine Hannover, who published the results of a small study on COVID-19 detection and dogs in July in BMC Infectious Diseases. “It’s exciting to think this could be an option for COVID detection.”
Canine Coronavirus Team in Training
Dr. Volk and his colleagues trained eight dogs from Germany’s armed forces to distinguish between saliva from patients with COVID-19 and saliva from a control group. Then they got samples from 1,000 people and tested the dogs to see whether they could identify those with the coronavirus. The dogs could, with 94 percent accuracy.
Another small study involving nine dogs from the University of Pennsylvania School of Veterinary Medicine in Philadelphia used urine samples from patients with COVID-19. Researchers found that dogs could detect the coronavirus with 95 percent accuracy.
“Our results from Phase 1 suggest that dogs are performing so well at ignoring COVID-negative samples that we’re moving into Phase 2,” says Martin Hackett, communications director at Penn Vet. Phase 2 would involve testing saliva from hospitalized patients who tested positive for COVID-19.
A similar effort is ongoing at the London School of Hygiene & Tropical Medicine by the same team of researchers who discovered that dogs can identify patients with malaria by smell. Those scientists are currently preparing a six-week training course for dogs to sniff out positive COVID-19 cases, with the goal of training a single canine to screen up to 250 people per hour.
What Kind of Smell Does COVID-19 Give Off?
Like other diseases, COVID-19 changes the metabolic processes of cells in the body, triggering the release of a signature scent that dogs are able to identify, explains Volk.?If you're not infected with the virus, your cells won't have the "pathogen-specific odor" that may be associated with COVID-19, so trained dogs pass you by.
It’s possible that one day researchers could develop “electronic dog noses,” which Volk says would be far more accurate than quick tests like temperature readings — a method that has limited effectiveness, since not everyone infected with the coronavirus has a fever.
A Future of Doggy Detectives
These recent studies are small pilot programs investigating whether it’s even worth taking the next steps to refine research protocols. But, Volk believes, that answer is yes.
“Next, we compare asymptomatic with symptomatic patients, and how specific the scent signature is in comparison to other respiratory diseases,” he says.
As the field of canine COVID research continues to evolve, a future of infectious disease doggy detectives might not be that far off.