Scent dogs may represent a cheaper, faster and more effective way to detect COVID-19, and could be a key tool in future pandemics, a new review of recent research suggests. The review, published in De Gruyter’s Journal of Osteopathic Medicine, found that scent dogs are as effective, or even more effective, than conventional COVID-19 tests such as RT-PCR.
Dogs possess up to 300 million olfactory cells, compared to just 5 or 6 million in humans, and use one-third of their brains to process scent information, compared with just 5% for humans. Dogs trained to recognize specific volatile organic compounds created in the body during disease have successfully identified patients with certain cancers, Parkinson’s and diabetes.
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.
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.