Dogs exhibit faster, more accurate Covid-19 detection through sniffing

In certain situations, the dog provided a swift sniff to signal the presence of Covid-19 in a person, while in other cases, the dog was presented with a sweat sample for detection, which could take a few minutes.

New York: Dogs can be a faster, more precise and less expensive method of detecting Covid-19 than even the best current technology around us, new research has revealed.

The magic lies in their highly evolved noses, with physical and neural optimisations for smell. Dogs have hundreds of millions of olfactory receptors, compared to roughly five to six million for humans, and a full third of their brains are devoted to interpreting smells, compared to a scant 5 per cent in human brains.

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All these enhancements mean that dogs can detect very low concentrations of odours associated with Covid infections.

A growing number of studies over the last two or so years has highlighted the power of dogs in detecting the stealthy virus and its variants, even when they are obscured by other viruses, like those from common colds and flu.

“It went from four papers to 29 peer-reviewed studies – that includes more than 400 scientists from over 30 countries and 31,000 samples,” said Tommy Dickey, a University of California-Santa Barbara Distinguished Professor Emeritus.

Dickey with collaborator Heather Junqueira of BioScent Inc., gathered the recent massive number of findings into a review published in the Journal of Osteopathic Medicine.

They assert that the collective research demonstrates that trained scent dogs are “as effective and often more effective” than the antigen tests we’re keeping handy at home, as well as the gold-standard reverse transcription polymerase chain reaction (RT-PCR) tests deployed in clinics and hospitals.

Not only can dogs detect the SARS-CoV-2 virus faster, they can do so in a non-intrusive manner, without the environmental impact that comes with single-use plastics.

“They can detect the equivalent of one drop of an odorous substance in 10.5 Olympic-sized swimming pools,” Dickey said. “For perspective, this is about three orders of magnitude better than with scientific instrumentation.”

In some cases, dogs were able to detect Covid in pre-symptomatic and asymptomatic patients whose viral load was too low for conventional tests to work.

Dogs can distinguish Covid and its variants in the presence of other potentially confounding respiratory viruses, such as those of the common cold or flu.

“They’re much more effective,” Dickey said. “In fact one of the authors that we quote in the paper commented that the RT-PCR test is not the gold standard anymore. It’s the dog”.

In some scenarios the dog gave the person a quick sniff, sitting down to indicate the presence of Covid. In others, the dog was given a sweat sample to smell, a process that could take a few minutes.

Scent dogs such as beagles, basset hounds and coonhounds would be the ideal dog for the task, given their natural tendencies to rely on odours to relate to the world, but the studies showed a variety of other dogs are up to the challenge.

“There’s quite a bit of research, but it’s still considered by many as a kind of a curiosity,” said Dickey.