By Katy Cable-A 3 minute Read
How many times have you been irritated by an annoying dog that comes running over and won’t stop sniffing you? Even if you love dogs, you’ll have to agree it’s a complete invasion of personal space. Well, that sniffing may soon be the first checkpoint to being able to jump on an airplane, attend school, or go to an event without any worry of catching the coronavirus. Imagine not having to shove a 12” swab up our noses until it tickles the back of our eye sockets. Instead, one would just need to allow a quick sniff by a working “COVID detecting Canine.” In some parts of the world, it’s already happening.
THE NOSE KNOWS
Depending on the breed, a dog’s sense of smell is around 10,000 - 100,000 times better than ours. That means the Chanel #5 I spray on every day must be overkill for my little Pug Olive. Dogs possess up to 300 million olfactory receptors in their noses compared to about six million in ours and the part of their brains that analyses and processes scents is (proportionally) 40 times greater than a humans. This gives dogs the ability to detect even infinitesimal amounts of a particular odorant. This would explain why dogs are widely used at airports for their keen ability to sniff out drugs and explosives. They also sniff out diseases, such as cancer and diabetes in humans. And now we are learning they are also experts at detecting COVID-19.
Researchers at France’s National Veterinary School in Maisons Alfort (near Paris) have revealed that dogs are experts at sniffing out COVID-19, with accuracy nearly as good as PCR tests.1
For the study, sweat samples were collected from 335 people, who were then tested for COVID 19 via a PCR test. -109 people tested positive. Nine dogs that had been trained to sniff out COVID, then sniffed the samples. The dogs were able to identify positive samples with an impressive 97% accuracy. In addition, in 91% of the cases, the dogs were able to identify negative samples.2
In an earlier proof of concept study, six detection dogs had a success rate per dog that ranged from 76% to 100%. “These results provide some evidence that detection dogs may be able to discriminate between sweat samples from symptomatic COVID-19 individuals and those from asymptomatic COVID-19 negative individuals,” the researchers concluded.3
MORE EXCITING RESEARCH
German researchers have also been working to train COVID-sniffing dogs. In a pilot study conducted by Volk and colleagues, published in July 2020, eight detection dogs were trained for one week to detect SARS-CoV-2 in the saliva or tracheobronchial secretions of people with COVID-19.4 The study revealed the dogs determined the difference between positive and negative samples with 82.63% sensitivity and 96.35% specificity. Overall, the average detection rate of the dogs was 94%.5. “No one is saying they can replace a PCR machine, but they could be very promising,” stated, veterinary neurologist Holger Volk, at the University of Veterinary Medicine Hanover in Germany. 6
A similar exciting research trial is underway at the University of Helsinki in Finland. Here, participants swab their skin using a tissue, then drop it into a jar that’s passed over to a dog to sniff. The results are then compared to the results of a PCR test.7 Lead researcher Anna Hielm-Björkman told Fortune:8
“It finds all the positives that the PCR finds and then [around] 5% more positives than the PCR. The dog is so much more sensitive. It finds more positives where people have had the disease and still have the virus in their body, even though they’re not contagious anymore. Also what it’s able to [do] is it can find the positive ones up to one week before they get their clinical symptoms.”
CAN THIS PUT DOGS IN HARM’S WAY?
Ever since this pandemic started, there have been many fears about how COVID affects dogs. Can they catch it from us? Or worse, can they infect us? If dogs are sniffing out this deadly virus, many will worry were putting them at risk. Luckily, the World Health Organization found that COVID-19 doesn’t pose a threat to pets. This work would not put the dogs in danger. Furthermore, it’s not the actual virus that the dogs are sniffing but the unique volatile organic compounds (VOCs) that humans let off in response to SARS-CoV-2.
DOGS OUTPERFORM PCR TESTS
“The dogs can do it,” says Cynthia Otto, leader of the Penn Vet Working Dog Centre at the University of Pennsylvania in Philadelphia. 6 tto’s team is collecting sweat samples from 1,000 T-shirts worn by people with and without COVID-19 to help understand which VOCs the dogs are detecting. Dogs now must be taught what the cut-off point is for very small amounts of the virus, which may exist in someone who is no longer contagious.
“The reason we haven’t changed the cutoff point yet is there is really no research yet on how long people are contagious. We will let the dogs tell us [that very small amounts of the virus have been detected] until there is enough science to back up a cutoff point. Then we’ll teach them again: ‘If it’s lower than this, you don't need to tell us,” Hielm-Björkman told Fortune.9
She’s confident in dogs’ ability, however, adding, “Dogs are superior to PCR tests.”10 It’s very likely that soon they may become regular additions to screening procedures at an airport near you.
HOW THIS MAY AFFECT THE PANDEMIC?
Specially trained police dogs are already being used to detect SARS-CoV-2 in passengers at Dubai International Airport. Samples are collected from passengers, which are then screened by the dogs, with results coming out in less than a minute.7 With each trained dog able to sniff up for 250 people per hour, the coronavirus risk could be decreased dramatically. If the virus is spotted on someone, those people can receive further testing for confirmation. Asymptomatic people could begin early treatments that may be lifesaving. This would make the testing process of much faster, more efficient, and less expensive.
And it’s not just COVID-19, the keen canine sense of smell also has the potential to detect other diseases in humans that have characteristic odors, including:
Urinary tract infections
Gastrointestinal (GI) disorders
Endocrine disorders (e.g., Cushing's syndrome)
It's possible that one day soon, while visiting your doctor's office you'll be asked to undergo a full “body sniff” by a four-legged, fur-covered physician's assistant! Wouldn’t that be great! These exciting new studies show that beloved dogs could actually hold the key to SAFELY resuming “life as we USED to know it!” They quite possibly could put an end to this horrible pandemic much sooner. In the meantime, I hope you’re staying healthy and safe!
1, 2, Bloomberg, May 19,2021
3, PLOS One December 10, 2020
4, 5, National Library of Medicine BMCInfect Dis. July, 2020
6 Nature, November 23, 2020
7, 8, 9, 10 Fortune, September 23, 2020
11, The National News,