Dogs Could Revolutionize the Sustainability of Future Pandemic Testing

One of the more frustrating roadblocks in navigating the COVID-19 pandemic was the difficulty in getting quick, accurate test results. Sometimes, results for PCR tests took up to two weeks, rendering their diagnosis useless for planning isolation scenarios. Meanwhile, rapid tests still oftentimes provide a false negative if taken too soon after infection. When I had COVID, I was four days into symptoms before I got a positive at-home test—I've heard many people recount similar stories.

The testing we have is certainly better than nothing, but it leaves a lot to be desired. If only there were a better way, say, using something with remarkable innate sensitivity. Like, dogs. Far-fetched? Not at all.

A review of recent research concluded that scent dogs may represent a cheaper, faster, and more effective way to detect COVID-19 and could be a key tool in future pandemics. This could be a game-changer for sustainability as well, eliminating the enormous amount of waste that comes with billions of testing kits.

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 PCR tests.

Most of us know that dogs have a remarkable sense of smell; they sniff out drugs and explosives and have even successfully identified patients with certain cancers, Parkinson’s, and diabetes. They have up to 300 million olfactory cells, compared to 5 or 6 million in humans. And they use one-third of their brains to process scent information—humans just use 5%.

Professor Tommy Dickey of the University of California, Santa Barbara, and Heather Junqueira of BioScent Detection Dogs analyzed 29 different studies in which dogs detected 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," explains a press statement from De Gruyter.

Dogs' Incredible Accuracy

The dogs ranged from Labrador retrievers and Belgian malinois to beagles and English springer spaniels. In most of the studies, the dogs demonstrated similar or better sensitivity and specificity than the current gold-standard 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," notes De Gruyter.

Remarkably, they not only detected COVID-19 in symptomatic, pre-symptomatic, and asymptomatic patients, but they could also sniff out COVID variants and even long COVID.

Considering the Safety of the Dogs

One thing we certainly don't want is for dogs to become collateral damage in the pursuit of better testing. The study authors acknowledge this, writing that the "safety of scent dogs, their handlers, and those who are inspected by the dogs is critical for the acceptance and implementation of the scent dog screening and testing approach."

"This is consistent with the One Health paradigm," they add, "which defines health as more than the absence of disease and recognizes the interrelationships among humans, animals, and environmental welfare."

The authors evaluated whether medical detection dogs could contract and become ill with the COVID-19 virus and if dogs pass on the COVID-19 virus to humans. From a number of studies, they concluded that dogs are in the low-risk category. "To our knowledge, there have been no deaths of dogs that can be unequivocally attributed to COVID-19," the authors explain. "Importantly, the studies described above suggest that it is safe for healthy individual handlers to utilize scent dogs to directly screen and test individuals who may be infected with the COVID-19 virus."

Speedy Test Results

A major benefit of using the dogs is their speed. In one study, researchers were able to do a lineup with 40 samples, including sample collection, lineup loading, and unloading, within just 3  minutes.

"The time between RT-PCR sampling and the return of results can be up to days, whereas the RAG test results are obtained within about 15 min.," write the study authors. "Again, if scent dogs directly sniff individuals, results are learned in seconds, or a few minutes if samples are taken and sniffed soon after by the dogs."

"The criticality of the speed of the return of test results cannot be overemphasized," the authors add.

Elimination of Plastic Waste

That dogs could provide a result in seconds to minutes is crucial. But additionally, and importantly, scent tests by dogs don't require expensive lab equipment or create mountains of plastic waste, unlike conventional diagnostic approaches.

As of December 22, 2022, the United States alone had performed around 1.15 billion tests for COVID-19. Thinking of all the material for the testing kits and all the resources used for testing labs and sending samples around, etc., the reduction in ecological footprint is potentially tremendous.

Not to mention the cost. Some of the research in the review was, in fact, motivated by the need for inexpensive testing in developing nations, the authors note.

“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,” says 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."