Trained dogs detect COVID-19 as well as PCR tests

Dogs are as reliable as laboratory tests to detect cases of COVID-19, and may be even better than PCR tests to detect infected people who have no symptoms. Bonus: Fangs are nicer and less invasive than a nasal swab.

The study involved sweat samples from 335 trained dogs sniffed out 97 percent of coronavirus infections which were detected by PCR tests, researchers report on June 1 PLOS One. And the dogs found all 31 cases of COVID-19 among 192 people who had no symptoms.

These findings are evidence that dogs can be effective for conducting mass surveys in places such as airports or concerts, and may be a friendly alternative to testing people who refuse nasal swabs, says Dominique Granjan, a veterinarian at the National School. Veterinary medicine Alfort in Maisons-Alfor, France.

“The dog doesn’t lie,” but there are many ways PCR tests can go wrong, Grange says. Nose fangs also detected more cases of COVID-19 than there were antigen assays (CH: 17.12.21), similar to many tests at home, but sometimes took another respiratory virus for coronavirus, found Grange and his colleagues. Moreover, indifferent data suggest that dogs can detect asymptomatic cases 48 hours before people get a positive PCR result, he says.

A study of dogs from French fire stations and the United Arab Emirates Interior Ministry trained them to detect the coronavirus by rewarding them with toys – usually tennis swords. “It’s a game for them,” says Grange. It takes three to six weeks to teach a dog to select COVID-19 cases from sweat samples, depending on the dog’s experience with odor detection.

The dogs then sniffed the bumps, which contained samples of sweat collected from the armpits of volunteer people. Washing sweat from people’s backs or giving woofers the spirit of used face masks worked just as well, Grange says.

These results suggest that odors from different parts of the body can be used to examine dogs, says Kenneth Furton, a forensic chemist at the International University of Florida in Miami who was not involved in the study.

The results are similar to previous, smaller studies that also showed that dogs performed just as well or even better than PCR tests to detect SARS-CoV-2, the virus that causes COVID-19, Furton says. He and his colleagues used dogs in schools, at a music festival and in a small test run by airline staff for coronavirus infections.

One of the biggest advantages dogs have over other tests is their speed, Furton says. “Even with what we call a quick test, you still have to wait tens of minutes or even hours for a dog to react in seconds or even fractions of a second.”

It is unclear what exactly dogs feel when they detect COVID-19 or other diseases, says Cynthia Otto, director of the Center for Working Dog Breeding at the University of Pennsylvania School of Veterinary Medicine, which was not involved in the study. It may not be a single chemical, but a model of increasing and decreasing the level of certain flavors. “It’s not that you could create a perfume bottle with a scent that would be a COVID scent,” she says.

Even with repeated studies demonstrating the ability of dogs to detect COVID, some doctors, scientists and government officials have been skeptical of the allegations, Grange says. He believes the reluctance is surprising because dogs are already used to sniffing out drugs and explosives, and are undergoing tests to detect other diseases such as cancer, he says. “Every time you get on a plane, it’s because the dogs sniff your luggage [and found] no explosives. So you trust them when you get on a plane, but you don’t want to trust them about COVID? ”

One problem with dogs, Furton says, is that people don’t consider them high-tech like electronic sensors. “But dogs are one of the most high-tech devices we have. These are just biological sensors, not electronic sensors, ”he says.

Another disadvantage of dogs is that they need time to train, and currently do not even have enough dogs trained to detect explosives, let alone diseases, says Otto. And “dogs that work well in this lab may not work well in humans,” she says. Handlers can also affect a dog’s reaction and need to be able to read the dog well, she says. “We need more good dogs.”

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