It’s official. Dogs operating out of a university clinic in Bangkok are part of a global corp of dogs being trained to sniff out Covid-19 in people. Preliminary studies, conducted in multiple countries, suggest that their detection rate may surpass that of the rapid antigen testing often used in airports and other public places.
The hope is that dogs can be deployed in crowded public spaces, like stadiums or transportation hubs, to identify people carrying the virus*. Their skills are being developed in Thailand, the United States, France, Britain, Chile, Australia, Belgium and Germany, among other countries. They have patrolled airports in Finland, Lebanon and the United Arab Emirates, and private companies have used them at American sporting events**.
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Dogs vs. human-made detection devices
The Covid-sniffing working dogs have so far accurately detected the virus 96.2 percent of the time in controlled settings, according to university researchers***. (Studies in Germany and the United Arab Emirates had lower but still impressive results.) Additionally, sniffer dogs work faster and far more cheaply than polymerase chain reaction, or P.C.R., testing, their proponents say. An intake of air through their sensitive snouts is enough to identify within a second the volatile organic compound or cocktail of compounds that are produced when a person with Covid-19 sheds damaged cells, researchers say. Another argument for using dogs to sniff out Covid virus is that some methods of detection, like temperature screening, can’t identify infected asymptomatic individuals (people who have no symptoms). But dogs can, because the infected lungs and trachea produce a trademark scent. And dogs need fewer molecules to nose out Covid than are required for P.C.R. testing. And finally, the dogs are much cheaper to use for virus detection. The cotton swabs and other basic equipment for canine testing work out to about 75 cents per sample. That is much cheaper than what’s needed for other types of rapid screening.
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The training
The six Covid-sniffing working dogs were assigned six handlers, who exposed them to sweat-stained cotton balls from the socks and armpits of Covid-positive individuals****. Within a couple months of training, at about 600 sniffs per day, the dogs were sitting obediently whenever they sensed the cellular byproducts of Covid-19 on cotton balls, which researchers placed at nose height on a carousel-like contraption.
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Low risks to the working dogs?
Researchers claim the risks to the working sniffer dogs are low. The coronavirus is not known to be easily transmissible through perspiration, a plentiful commodity in tropical Thailand. Instead, the main transmission route appears to be respiratory droplets. It should be noted that on rare occasions, pet cats and dogs in close contact with infected humans have tested positive for the virus, as have populations of minks and other mammals. There are no proven cases, however, of household pets passing the virus to humans. That said, the Covid-sniffing working dogs are not ordinary “household pets”.
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*The Thai sniffer dogs are part of a research project run jointly by Chulalongkorn University and Chevron (yes, the Big Oil company). Chevron had previously used dogs to test its offshore employees for illegal drug use.
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**In the United States, dogs have been used to screen for Covid-19 at a handful of privately run events, including checking ticket holders at Miami Heat games and sniffing the sweaty feet of revelers at a wine and food festival in South Beach. But there are no national standards or government programs for using the dogs.
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***Dogs, whose wet snouts have up to 300 million olfactory receptors compared with roughly six million for humans, can be trained to memorize about 10 smell patterns for a specific compound. Dogs can also smell through another organ nestled between their noses and mouths.
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****Some research has suggested that dogs of various breeds may also be able to detect diabetes, Parkinson’s disease, malaria and certain cancers — that is, the volatile organic compounds or bodily fluids associated with them.
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Source: New York Times
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