Dogs sniff out coronavirus ‘far better than machines or tests’

By Justin Cremer

May 27, 2020

Can man’s historic best friend help in the fight against man’s current greatest enemy? Research teams around the world are taking advantage of dogs’ remarkable sense of smell to train them to detect the presence of the coronavirus.

At the University of Helsinki, researchers believe that the sniffer dogs Kössi and Lucky may prove to be faster and more accurate detectors of SARS-CoV-2, the virus that causes COVID-19, than any other currently available method.

Using urine samples collected from patients across Finland, the research team has trained the dogs to differentiate between positive and negative samples. More encouragingly, the dogs also appear to be able to detect the presence of COVID-19 before patients display any signs of illness.

Anna Hielm-Björkman, an associate professor of animal clinical research at the university, said that her team has collected urine samples from family members of COVID patients that had not yet been tested or had previously tested negative. In many cases, the dogs picked up on the presence of the disease and when researchers then asked those family members to submit to traditional tests, they were confirmed as positive.

“We found that the dogs could see that a person was getting sick about four to five days before they got the disease. That was really encouraging because it means that the sensitivity of the dogs is better than the tests,” Hielm-Björkman said.

Current testing for COVID-19 typically gives results in two to three days, but the dogs are able to provide instant results. This is part of the reason that similar research projects are underway in the United States, France, Germany, Switzerland and Japan. The United Kingdom government recently announced a US$549,000 grant to fund a study on COVID-sniffing dogs by Durham University, the London School of Hygiene and Tropical Medicine and the charity Medical Detection Dogs.

A research project at the University of Pennsylvania’s School of Veterinary Medicine (Penn Vet) that is training dogs to detect COVID-19 positive saliva and urine is expected to begin preliminary screening on live human subjects as early as July.

Putting ‘pee-mail’ skills to good work

The reason the dogs are so good at sniffing out the presence of the virus is, of course, their remarkable sense of smell. While dogs’ habit of sniffing everything they pass can be maddening to the humans accompanying them on their walks, this processing of “reading their pee-mails,” as Hielm-Björkman put it, yields all sorts of information and allows them to identify certain smells. Detection dogs can be trained to sniff out anything from mold to illicit drugs or missing persons. With the right training, they can also detect the presence of the source of the greatest pandemic in living history.

“The sense of smell that dogs have is millions or even billions times better than the machines that are used to look for molecules. The dogs can find molecules in very, very small concentration. For example if you had a glass of water containing between one and 100 molecules of whatever you’re looking for, a dog could find it, whereas the best types of machine detection systems would need 18 million molecules,” Hielm-Björkman said.

Hielm-Björkman stressed that additional research needs to confirm whether the dogs are specifically detecting SARS-CoV-2 rather than the presence of another virus, but said preliminary results are very promising. In recent days, her team presented urine samples from patients who had non-coronavirus related illnesses like asthma and bronchitis and the dogs did not react. This leads her to believe that after additional testing, the specificity question will soon be settled.

The Helsinki dogs used in the COVID detection program were selected from a roster of cancer detection dogs that Hielm-Björkman’s team has been working with for the past four to five years. Because of the novelty of the coronavirus, they did not want to put dogs or their handlers into any kind of unnecessary danger. Lucky and Kössi were selected because they are the dogs of a member of the research team. In Kössi’s case, an exhibited talent for sniffing out illness was also a decisive factor. Originally found abandoned in a cardboard box along the highway in Malaga, Spain, Kössi was taken to a shelter and eventually adopted and brought home to Finland. As a puppy, the Galgo mix showed an unusual interest in the mouths of a dog and cat he lived with, leading his handler to have them checked for cancer. Both were positive.

International effort

While Kössi’s journey is a remarkable one, Hielm-Björkman said that “any dog in any country could be trained to do the same thing.” Provided that they’re motivated to work for treats, that is.

Her team in Helsinki has been in close contact with their counterparts in Pennsylvania and the UK and she said everyone involved in this research sees amazing potential for using dogs to help in the fight against COVID-19 and future pandemics. Of the 500 or so professional detection dogs in Finland, she estimates that around 50 could be working as COVID sniffers by the fall, looking for the presence of coronavirus at border crossings and in concentrated living facilities like nursing homes. Because dogs can provide nearly instant results, they could also keep essential workers out of unnecessary quarantines.

Somewhat surprisingly, Hielm-Björkman pointed to financial savings as one of the main reasons to use detection dogs.

“When you think about how much money each and every country has now used to combat and control COVID, it’s crazy to think how different the world would look if we would have had those dogs. But it’s never too late to start a good thing, so I just hope that governmental bodies and funders can see the potential in this,” she said, adding that a comprehensive dog detection training program could cost as little as US$1.1 million.

“I think that when we get the first published, peer-reviewed data that shows that this really works and that dogs are actually far better than the machines and tests that are currently available, then I think that governments will start getting interested,” she added.

Photo caption: Kössi sniffs for the coronavirus at the University of Helsinki. Image: Anna Hielm-Björkman