By Sonia Fernandez, UC Santa Barbara
For about 15,000 years, dogs have been our hunting partners, workmates, helpers and companions. Could they also be our next allies in the fight against COVID-19?
According to UC Santa Bárbara professor Tommy Dickey and his collaborator, BioScent researcher Heather Junqueira, they can. And with a review article published in the Journal of Osteopathic Medicine, they added to a small but growing consensus that sniffer-trained dogs can be used effectively to screen individuals who may be infected with the COVID virus. -19.
This follows a comprehensive research survey dedicated to the use of dogs trained to detect COVID. “The most surprising result is that studies have already shown that dogs can identify people with positive COVID-19,” said Dickey of his findings. “Not only that,” he added, “they can do this non-intrusively, faster and with comparable or possibly better accuracy than our conventional detection tests.”
Not surprisingly, the magic is in the canine sense of smell, which gives dogs the ability to detect molecules in small concentrations – “a part of a quadrillion compared to a part of a billion for humans,” according to the article. Add to that other optimizations for smell, such as the large nasal area and the structure of the nose, which allows entry through the nostrils and exit through the nasal folds. In addition, with 125-300 million olfactory cells and a third of their brains dedicated to interpreting odors, dogs are well equipped with the ability to sniff out volatile organic compounds that indicate the presence of COVID.
Professor Emeritus Tommy Dickey and one of his Great Pyrenees therapy dogs
“Dogs are basically smelling a person’s sweat,” said Dickey of a series of experiments by French and Lebanese researchers who tested dogs’ ability to detect COVID infection. Although the virus itself has no odor, metabolic products excreted by COVID-positive individuals through their sweat glands were detected by the 18 dogs selected for the study (16 Belgian malinois, a German shepherd and a Jack Russell terrier) with an accuracy rate 83 -100% after just four days of training. True flaws, according to the study, can be attributed to “distracting external smells or movements by a TV film crew”.
“A dog twice indicated positive results that could not be confirmed,” said Dickey. “Two weeks later, they found that the two people who gave the samples had to be hospitalized with COVID.”
Meanwhile, a German research group employed eight odor-detecting dogs in a double-blind, randomized, controlled pilot study. The group trained the dogs for a week and then put them to smell 1,012 samples of saliva or tracheobronchial secretions. They returned an average detection rate of 94% with a sensitivity (ability to detect a true positive) from 67.9% to 95.2% and a specificity (ability to detect a true negative) from 92.4% to 98, 9%. This pilot study used positive samples from severely affected individuals and negative samples from people without symptoms. Future studies, according to that article, could focus more on identifying different stages of infection or perhaps on detecting different disease phenotypes.
Using dogs to detect disease is not new. In fact, co-author Junqueira published results showing that his sniffer dogs (beagles, bassett hounds and mixtures of the two) can effectively detect non-small cell lung cancer.
“Canines are able to detect other types of cancer, in addition to malaria, Parkinson’s disease and diabetes,” said Junqueira, adding that “research on dogs with medical smells has really only gained strength in recent years and that it will require many more revised articles By peers before the idea of using dogs for disease detection became popular. “
Dickey’s own interest in the subject was sparked throughout his work as a training dog trainer in three Great Pyrenees (more than 3,000 therapy dog visits), a long-standing occupation he relied on after cancer forced him to retire from the Department of Geography at UC Santa Bárbara in 2013. “I loved UCSB,” he said. “I loved teaching and took my therapy dogs to class all the time. I just had life, what can I say? ”
In fact, he couldn’t stay away – he and his dogs were available to see the UCSB community in difficult times, offering their shaggy coats, wet noses and calm demeanor during tragedy and stress. In retirement, Dickey published three books of therapy dogs for children, some of which recount stories of his UCSB therapy dog adventures. In addition, he and his canines presented educational demonstrations at the California Science Center and the Los Angeles Public Library, a work that sparked his interest in the power of a dog’s sense of smell for medical detection.
So, when the new disease called COVID-19 appeared, Dickey was prepared to ask: Can dogs detect the new coronavirus? Of course, there was little research referenced on the subject, so he joined Junqueira, who was already conducting his own COVID detection research with his sniffer dogs in Florida. “One of our biggest motivations was to write a peer-reviewed article that basically provided a progress report,” he said. “Where are we? Is this really possible?”
Dickey and Junqueira found that the researchers used a variety of dogs. “Many Belgian malinois have been used and dogs that have been trained in explosives and colon cancer. So they were professional sniffers, ”said Junqueira. “Other groups, like the one behind a Colombian study, were motivated by the need to find a fast, accurate and economical way of early detection of COVID.” The Colombian group used a variety of dogs – four Belgian malinois, a mix of Alaskan and Siberian malamute and an American pit bull terrier.
“The pit bull had already been mistreated,” said Dickey, “but they rehabilitated him, and he was perfectly capable and was doing a great job as a sniffer.” After almost two months of training and thousands of samples later, this Colombian canine cohort performed remarkably with 95.5% sensitivity and 99.6% specificity.
During the various blind and controlled experiments, the total time to detection was a matter of minutes or less. This speed is a great asset in real-world scenarios. In particular, a UK-based research group outlined its plans to train and ultimately deploy dogs at UK airports and ports of entry as part of the COVID-19 screening process.
With all the sniffing that occurs in the presence of an airborne disease, it’s natural to worry about whether dogs can catch and transmit COVID-19. It is still the subject of ongoing research, but the evidence points to a low likelihood of transmission, according to the newspaper, although precautionary measures should be taken to protect everyone involved.
“Current research supports the use of odor detection dogs for pilot COVID-19 screening studies involving humans in places like airports and sporting events,” said Dickey. “In addition, the JOM article points out that another line of research can use dogs to detect medical odors involving the development of medical electronic noses.”
In principle, you wouldn’t even need a dog to sniff out COVID if you could mimic the way it smells and processes smells, according to the researchers. Through sensors and artificial intelligence, they said, it may be possible someday to compare a dog’s performance using wearable electronic noses, similar to wristband sensors to report heart rate and patterns, blood pressure and oxygen, which can monitor a person’s sweat for metabolites and biomarkers that can indicate diseases like COVID-19.
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