Dogs are well known for their keen ability to sniff out drugs and explosives, making them invaluable at airports, train stations and other areas where large numbers of people congregate. Dogs also sniff out diseases, such as cancer in humans and foulbrood — a lethal bee disease — in bees.
Researchers at France’s National Veterinary School in Maisons Alfort near Paris have also revealed that dogs are experts at sniffing out COVID-19, with accuracy nearly as good as PCR tests. In the near future, it’s possible that COVID-19 screening dogs could work at airports to detect the SARS-CoV-2 virus among travelers.
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Dogs Detect COVID-19 With 97% Sensitivity
For the study, sweat samples were collected from the armpits of 335 people, who were then tested via PCR test for COVID-19 — 109 people tested positive. Nine dogs that had been trained to sniff out SARS-CoV-2 then sniffed the samples. The dogs were able to identify positive samples with an impressive 97% sensitivity, along with being 91% specific — a measure of the dogs’ ability to identify negative samples.
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.
“No one is saying they can replace a PCR machine, but they could be very promising,” veterinary neurologist Holger Volk at the University of Veterinary Medicine Hanover in Germany told Nature. 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.
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%, with researchers noting:
“These preliminary findings indicate that trained detection dogs can identify respiratory secretion samples from hospitalised and clinically diseased SARS-CoV-2 infected individuals by discriminating between samples from SARS-CoV-2 infected patients and negative controls. This data may form the basis for the reliable screening method of SARS-CoV-2 infected people.”
‘Dogs Are Superior to PCR Tests’
“The dogs can do it,” Cynthia Otto, leader of the Penn Vet Working Dog Centre at the University of Pennsylvania in Philadelphia, told Nature. “The challenge is the ignorance that we have as humans as to what can confuse the dogs.”
Otto’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 would also have to be taught a cut-off point for very small amounts of the virus, which may exist in someone who is no longer contagious.
“Some PCR tests do the same thing… 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.
She’s confident in dogs’ ability, however, adding, “Dogs are superior to PCR tests.” It’s quite possible that one day soon they may become regular additions to screening procedures at an airport near you.
There is light at the end of the tunnel
Dogs Are Already Sniffing Out COVID-19 in Dubai
In Dubai, 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.
A similar trial is underway through the University of Helsinki, in which passengers in Finland swab their skin for sweat using a tissue, then drop it into a jar that’s passed over to a dog to sniff. In just seconds, results are in, which are then compared to the results of a PCR test. Lead researcher Anna Hielm-Björkman told Fortune:
“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.”
More research is still needed before dogs can be used to sniff out COVID on a large scale. For instance, 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 this specific illness.
Bonus:
The latest Peter Abrahams novel, written under the Spencer Quinn moniker™. Tender Is The Bite is the new Chet and Bernie novel. how about this little snippet? (chet is a dog, partner with Bernie in a detective agency, books are written from his point of view generally) ...
“I have other sources,” Rick said. “How was your visit?”
“I found out why you’re in such a pissy mood.”
Rick was in a pissy mood? Wow! How could Bernie know something like that over the phone? Pissy moods give off a very distinctive smell – you don’t need me to tell you that – but I’ve never picked up that smell over the phone. Or any other smell, come to think of it. Was it possible I hadn’t been trying hard enough?
“Hang on a minute, Rick,” Bernie was saying. “Chet? Big guy?”
“What’s he doing?” Rick said.
“Kind of pressing his nose into the speaker for some reason,” Bernie said. “Denting it, in fact. Chet! Cool it!”
Wow! Was this interesting or what? Things changed big time when you got your nose inside this –what was it called? Speaker, maybe? It really didn’t matter. The point was that on the inside I could actually feel Rick’s voice! I could feel his breathing! And buried down a layer or two in that voice and that breathing, I could feel a pissy mood! Could I even … ? Yes! I could! I could smell piss! The real thing! I’d been missing so much! From now on, every single time without exception that we were in the car, I was going to plant my –
“CHET!”
Escape the New Normal
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