Dogs Can Sniff Out Coronavirus – With Impressive Accuracy

Poncho, a two-and-a-half-year-old yellow Labrador retriever, was one of the dogs trained in a Penn Vet-led study to see if his and his fellow canines’ sensitive noses were positive for negative SARS. Could distinguish CoV-2. samples. Credit: Pat Nolan

In a proof-of-concept study led by the School of Veterinary Medicine, dogs identified positive samples with 96% accuracy.

Many long for a return to a post-pandemic ‘normal’, which for some may involve concerts, travel and large gatherings. But how can you protect yourself against these potential public health risks?

One possibility, according to a new study, are dogs. A proof-of-concept study recently published in the journal PLOS ONE suggests that specially trained tracking dogs can detect COVID-19 positive samples with 96% accuracy.

“This is not an easy thing we ask dogs to do,” said Cynthia Otto, senior author of the work and director of the Working Dog Center at the University of Pennsylvania School of Veterinary Medicine. “Dogs need to be specific in detecting the odor of the infection, but they also need to generalize about the background smells of different people: men and women, adults and children, people of different ethnicities and geographies.”

In this first study, the researchers found that the dogs could, but training must be done with great care and ideally with many samples. The findings feed on another study Otto and colleagues called “ the T-shirt study, ” in which dogs are trained to distinguish between the smells of COVID-positive, negative, and vaccinated individuals based on the volatile organic compounds. . they leave them on a T-shirt that is worn at night.

“We are collecting many more samples – hundreds or more – in that study than in this initial study, and we hope this will bring the dogs closer to what they might encounter in a community setting,” says Otto.

The nine dogs in the study, including Miss M, above, were 96% accurate in identifying positive samples. Credit: Pat Nolan

Through the Working Dog Center, she and colleagues have years of experience training medical tracking dogs, including dogs that can identify ovarian cancer. When the pandemic arrived, they used that expertise to set up a coronavirus detection study.

Collaborators Ian Frank of the Perelman School of Medicine and Audrey Odom John of Children’s Hospital in Philadelphia provided SARS-CoV-2 positive samples from adult and pediatric patients, as well as samples from patients who tested negative to serve as experimental controls. Otto worked closely with Penn Medicine coronavirus expert Susan Weiss to process some of the samples in Penn’s Biosafety Level 2+ lab to inactivate the virus so the dogs could smell them safely.

Due to the workplace closure due to the pandemic, instead of working with dogs at Penn Vet, the researchers teamed up with Pat Nolan, a trainer with a facility in Maryland.

Eight Labrador retrievers and a Belgian Malinois who had not previously done medical tracking work were used in the study. First, the researchers trained them to recognize a distinctive odor, a synthetic compound known as universal detection compound (UDC). They used a ‘scent wheel’ in which each of the 12 gates is loaded with a different sample and they rewarded the dog when he responded to the gate with UDC.

When the dogs responded consistently to the UDC odor, the team began training them to respond to urine samples from SARS-CoV-2 positive patients and to distinguish positive from negative samples. The negative samples were subjected to the same inactivation treatment – either heat inactivation or detergent inactivation – as the positive samples.

Processing the results with help from Penn criminologist and statistician Richard Berk, the team found that after three weeks of training, all nine dogs were able to easily identify SARS-CoV-2 positive samples, with an average accuracy of 96%. However, their sensitivity, or ability to avoid false negatives, was partially lower, the researchers believe, because of the study’s strict criteria: If the dogs walked through a gate with a positive sample, even once without responding, that’s labeled a “miss.”

The researchers encountered many complicating factors in their study, such as the dogs’ tendency to differentiate between the actual patients, rather than their SARS-CoV-2 infection status. The dogs were also discarded with a sample from a patient who tested negative for SARS-CoV-2, but had recently recovered from COVID-19.

“The dogs kept responding to that sample, and we kept saying no,” Otto says. “But there was clearly something else in the patient sample that the dogs were honking at.”

Important lessons learned from the study, in addition to confirming that there is a SARS-CoV-2 odor that dogs can detect, were that future training should include large numbers of different samples and that dogs should not be repeatedly trained on the samples from a single individual. .

“That’s something we can continue not only in our COVID training, but also in our cancer work and all the other medical screening efforts we do,” Otto says. “We want to make sure we have taken all steps to ensure quality, reproducibility, validity and safety for when we operationalize our dogs and have them screened in community settings.”

Reference: “Discrimination of SARS-CoV-2 Infected Patient Specimens by Detection Dogs: A Proof of Concept Study” by Jennifer L. Essler, Sarah A. Kane, Pat Nolan, Elikplim H. Akaho, Amalia Z. Berna, Annemarie DeAngelo, Richard A. Berk, Patricia Kaynaroglu, Victoria L. Plymouth, Ian D. Frank, Susan R. Weiss, Audrey R. Odom John, and Cynthia M. Otto, April 14, 2021, PLOS ONE.
DOI: 10.1371 / journal.pone.0250158

Cynthia M. Otto is a professor of working dog science and sports medicine and director of the Working Dog Center at the University of Pennsylvania School of Veterinary Medicine.

Otto’s co-authors on the study were Jennifer L. Essler, Sarah A. Kane, Annemarie DeAngelo, Patricia Kaynaroglu, and Victoria L. Plymouth of Penn Vet; Ian D. Frank and Susan R. Weiss of Penn’s Perelman School of Medicine; Elikplim H. Akaho, Amalia Z. Berna, and Audrey R. Odom John of Children’s Hospital in Philadelphia; Richard A. Berk of Penn’s School of Arts & Sciences; and Pat Nolan from Tactical Directional Canine. Essler was the lead author of the study.

The study was funded in large part by Vernon and Shirley Hill with additional support from the National Institutes of Health (grants AI144472, AI154370, DH105594 and R01-140442), the Burroughs Wellcome Fund, and the Ovarian Cancer Symptom Awareness Fund.