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Sniffing Out COVID-19: How Scent Dogs Outperform Modern Testing Methods

Sniffing Out COVID-19: How Scent Dogs Outperform Modern Testing Methods

Aug 8, 2023
Dog at Doctor's Office

A recent review suggests that scent dogs could be a cost-effective, quick, and highly accurate tool for detecting COVID-19 and may play a key role in future pandemics. These dogs have been shown to outperform conventional tests, identify various stages and strains of the virus, and are primed for broader health screening applications.

Research review finds scent dogs can successfully sniff out COVID-19, including asymptomatic cases, new variants, and long COVID.

Scent dogs could provide a cheaper, faster, and more effective method of detecting COVID-19, and they could prove crucial in managing future pandemics, according to a new review of recent research. This review, published in De Gruyter’s Journal of Osteopathic Medicine, found that scent dogs perform as well as or even better than conventional COVID-19 tests, such as RT-PCR.

Dogs are equipped with up to 300 million olfactory cells, which significantly surpasses the human count of just 5 or 6 million. In addition, dogs dedicate one-third of their brains to processing scent information, compared to the mere 5% utilized by humans. Dogs trained to identify specific volatile organic compounds produced in the body during illness have been successful in pinpointing patients with certain types of cancer, Parkinson’s disease, and diabetes.

Review of Studies

Prof. Tommy Dickey of the University of California, Santa Barbara and Heather Junqueira of BioScent Detection Dogs reviewed 29 studies where dogs were used to detect COVID-19. The studies were performed using over 31,000 samples by over 400 scientists from more than 30 countries using 19 different dog breeds. In some studies, the scent dogs sniffed people directly, sometimes in public places as a health screening. In others, the dogs sniffed patient samples such as sweat, saliva or urine samples.

How Scent Dogs Are Trained

(A) Illustration of the three cup sniffing experiment with the first author’s Great Pyrenees (photo credit: Todd Dickey). (B) One of the second author’s COVID-19 scent dogs sniffing a test canister (photo credit: Heather Junqueira). (C) Flowchart illustrating how volatile organic compounds (VOCs) are sensed and processed by dogs and ENoses (flowchart modified after Karakaya et al., 2020, with permission). Credit: (A) Todd Dickey, (B) Heather Junqueira, (C) Flowchart modified after Karakaya et al. with permission (Karakaya, D, Ulucan, O, Turkan, M. Electronic nose and its applications: a survey. Int J Autom Comput 2020;17:179-209. https//doi:10.1007/s11633-019-1212-9).

In the majority of studies, the scent dogs demonstrated similar or better sensitivity and specificity than the current gold-standard RT-PCR tests or antigen tests. In one study, four of the dogs could detect the equivalent of less than 2.6 x 10−12 copies of viral RNA per milliliter. This is equivalent to detecting one drop of any odorous substance dissolved in ten and a half Olympic-sized swimming pools and is three orders of magnitude better than modern scientific instruments.

Advantages and Applications

The dogs could detect COVID-19 in symptomatic, pre-symptomatic, and asymptomatic patients, along with new COVID variants and even long COVID. A major benefit of using the dogs was their speed – they could provide a result in seconds to minutes, and did not require expensive lab equipment or create mountains of plastic waste, unlike conventional diagnostic approaches.

“Although many people have heard about the exceptional abilities of dogs to help humans, their value to the medical field has been considered fascinating, but not ready for real-world medical use,” said Prof. Dickey. “Having conducted this review, we believe that scent dogs deserve their place as a serious diagnostic methodology that could be particularly useful during pandemics, potentially as part of rapid health screenings in public spaces. We are confident that scent dogs will be useful in detecting a wide variety of diseases in the future.”

Prof. Dickey and Heather Junqueira added that they feel that the impressive international COVID scent dog research described in their paper, perhaps for the first time, demonstrates that medical scent dogs are ready for mainstream medical applications.

Reference: “COVID-19 scent dog research highlights and synthesis during the pandemic of December 2019−April 2023” by Tommy Dickey and Heather Junqueira, 17 July 2023, Journal of Osteopathic Medicine.
DOI: 10.1515/jom-2023-0104


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