(p. A1) . . . three Labradors, operating out of a university clinic in Bangkok, are part of a global corps 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.
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(p. A6) . . . as a group, the dogs being trained in Thailand — Angel, Bobby, Bravo and three others, Apollo, Tiger and Nasa — 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.
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.
“P.C.R. tests are not immediate, and there are false negative results, while we know that dogs can detect Covid in its incubation phase,” said Dr. Anne-Lise Chaber, an interdisciplinary health expert at the School of Animal and Veterinary Sciences at the University of Adelaide in Australia who has been working for six months with 15 Covid-sniffing dogs.
Some methods of detection, like temperature screening, can’t identify infected 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, Thai researchers said.
The Thai Labradors are part of a research project run jointly by Chulalongkorn University and Chevron. The oil company had previously used dogs to test its offshore employees for illegal drug use, and a Thai manager wondered whether the animals could do the same with the coronavirus.
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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, Dr. Kaywalee said. Dogs can also smell through another organ nestled between their noses and mouths.
Some research has suggested that dogs of various breeds may be able to detect diabetes, Parkinson’s disease, malaria and certain cancers — that is, the volatile organic compounds or bodily fluids associated with them.
Labradors are among the smartest breeds, said Lertchai Chaumrattanakul, who leads Chevron’s part of the dog project. They are affable, too, making them the ideal doggy detector: engaged and eager.
Mr. Lertchai noted that Labradors are expensive, about $2,000 each in Thailand. But 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.
(Note: the online version of the commentary has the date May 31, 2021, and has the title “On the Covid Front Lines, When Not Getting Belly Rubs.”)