Dogs successfully trained to sniff out COVID could prevent virus spread at airports and travel hubs

Man’s best friend has an amazing sense of smell. Dogs are credited odor connoisseurs with up to 300 million olfactory receptors in their noses (compared to a measly five to six million in humans) and 40 percent more brain space devoted to analyzing odors. Fido can pick up the slightest whiffs of any scent better than any man-made instrument. It’s a super canine ability that we’ve been using to help find missing people (looking for Lassie), locate illegal drugs and dangerous compounds like explosives, and catch contraband. And now we are using it to eradicate COVID-19.

In a new study published Monday in the British medical journalFinnish researchers found that dogs trained to sniff out the coronavirus could detect it among airport travelers with nearly 100% accuracy, raising hopes that our furry friends could provide rapid and effective detection of COVID infections not only in crowded public spaces or travel centers — places considered to be at higher risk of transmitting the virus — but also hospitals and even schools.

“This is a very important study showing that COVID-19 detection dogs can achieve greater than 90 percent accuracy and sensitivity, which is comparable to current testing methods, but much faster,” said Kenneth Furton, biochemist at Florida International University who was not involved in the study. study, but has previously studied the use of dogs to detect COVID infections, he told The Daily Beast in an email. “COVID-19 detection dogs provide results in seconds rather than minutes or hours and can therefore test large numbers of people without delay.”

The idea of ​​using smell to diagnose diseases dates back to ancient times. A human’s sense of smell isn’t strong enough on its own, but a dog’s might be. Studies have shown that our four-legged companions can smell volatile organic compounds (VOCs), which are specific chemicals produced by the human body that enter our blood, urine, feces, skin, or breath.

The dogs have been trained to detect VOCs unique to diseases such as epilepsy, cancer, diabetes, and infections caused by pathogens such as malaria. When the pandemic hit, scientists hypothesized that the canine’s sensitive nose might also smell COVID. And that seemed to be the case: Several preliminary studies from France, the United Kingdom, Germany and the United Arab Emirates found that people infected with the virus had a particular scent of sweat that the uninfected lacked, which dogs could pick up.

In the new study, Finnish researchers took already-trained sniffer dogs and had them learn the smell of coronavirus sweat. The four dogs were then made to sniff more than 420 skin swabs, a quarter of them from volunteers who tested positive for COVID and the rest from those who tested negative. The results were impressive: the trained trackers had a combined diagnostic accuracy of 92 percent in detecting which samples were infected or not.

Then the canine noses went to work again, this time screening passengers at Finland’s Helsinki-Vantaa International Airport. During a pilot program that lasted about four months in the fall of 2020, the dogs’ sniff tests were compared to 303 COVID PCRs taken from incoming travelers. The 296 swabs identified as negative by the PCR tests were also identified as negative by the dogs, meaning their accuracy approached 98 percent. There were three positive cases that the dogs missed, one due to the alpha variant, which the dogs were not trained to sniff.

There are still important questions that have not yet been answered. For one, scientists do not yet know the specific VOC related to COVID. Another is what these findings mean for populations with a high prevalence of COVID-19 as there was not much of the virus among the airport passengers studied. The Finnish researchers estimate that in hypothetical high prevalence scenarios, such as what you might see in a hospital or assisted living facility during the height of an outbreak, dogs could still have fairly high accuracy at 88% for positive cases and almost 95% for negative cases. cases. However, further studies with much larger data sets are needed to see if this is true.

There is also the practicality of training large groups of COVID-19 detection dogs around the world and for different variants. For example, the dogs in the Finnish study were unable to detect a positive case that caused the alpha variant because they were used to the original variant of the coronavirus without major mutations.

“We didn’t think that dogs would distinguish the different variants,” Dr. Anna Hielm-Björkman, a veterinarian at the University of Helsinki and lead author of the study, told The Daily Beast in an email. “But with this information in hand, we now know that even minute changes in pathogens require us to retrain with these new variants. This new information is crucial for the next epidemic. At the same time, there’s nothing to worry about, as we know it’s quick and easy to retrain dogs that can already sniff out human diseases.”

Sniffer dogs could still be a promising avenue for rapid, effective and potentially life-saving detection, especially if COVID is here to stay. In the US, Furton and colleagues at Florida International University conducted two pilot programs testing COVID-19 detection dogs at Miami International Airport with promising results. Dogs trained to detect COVID on surfaces are already being used in some Massachusetts schools. And some made their cute, if solemn, appearance during a Miami Heat basketball game in February 2021. And while COVID-19 can spread to pets that are in close contact with humans, dogs seem to be largely safe from infection. Man’s best friend could become our best tool in the fight against COVID.

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