One Dogs’ sense of smell is thousands of times stronger than humans. Their superior canines are the reason why canines are used in law enforcement; Once they’re trained to detect certain scents, like drugs and explosives, they can find tracks that the human nose can never detect. The same skill translates into medicine. Research shows that dogs can find evidence of cancer and other diseases with impressive accuracy — and a recent study add more evidence to suggest The same is true for SARS-CoV-2the virus that causes COVID-19.
In the study, published in the journal PLOS ONE and build on a smaller one is published in 2020, dogs belonging to the French fire department and the UAE Ministry of the Interior were trained to recognize the smell of compounds related to SARS-CoV-2 in human sweat samples. The authors write: “The welfare of the dogs is fully respected, with toy rewards and absolutely no physical or mental fatigue caused by work.
The researchers then collected sweat from the armpits of nearly 350 people seeking to test for COVID-19 at sites in Paris. About a third of people get a positive result through a PCR test.
The dogs’ overall sensitivity (likelihood of receiving a positive sample) was 97%, while their overall specificity (the ability to determine that a sample was negative) was 91%. Study co-author Dominique Grandjean, a professor at France’s Alfort School of Veterinary Medicine, said the dog’s diagnostic ability ranks on par with the gold standard PCR tests.
Grandjean says that almost any dog can be trained to do this type of detection in a matter of weeks. “We probably have hundreds or thousands of dogs doing this for almost [no money]and they will be just as effective as PCR,” said Grandjean.
The dogs are likely to be deployed in crowded areas, like airports or conventions, or in other places where traditional testing is not widely available, to detect positive cases. They can also be used to test people who have not responded well to invasive nasal swabs, such as those with autosuggestion or neurodegenerative diseases, says Grandjean.
There is already some proof of concept. Finland’s Helsinki-Vantaa International Airport tested with COVID sniffer dogs in 2020, and research published in May showed their accuracy to be around 98%, although there were not enough positive cases to draw firm conclusions about sensitivity. Miami International Airport also tested Dog Sniffing COVID last year, many school in Massachusetts.
According to a study co-authored by Grandjean, dogs can also detect viral compounds in the sweat of COVID patients for up to 18 months after they first contracted the virus. Posted in January on MedRxiv, a server for new research that has not been peer-reviewed. The Canines in that study detected evidence of the virus in samples from 23 of the 45 patients with Long COVID in the trial, but not in any sweat samples from 188 people without Long COVID. Co-author Emilie Seyrat (who has Long COVID) said that exact rate is likely an underestimate, because some samples had to be mailed over the summer and so could have been affected. by temperature and time.
However, the results are fascinating. Scientists do not fully understand why some people develop chronic symptoms after a case of COVID-19, but one of the main theories is that remnants of the virus remain in some people’s systems and have the ability to continue to replicate, causing long-term health problems.
Dominique Salmon-Ceron, an infectious disease specialist at the Hôtel-Dieu Hospital in Paris and another author on the Long COVID study, said dogs can smell compounds associated with the virus more than one years after the original human became ill. “Our results add to the argument that the virus can survive” in the body, she said.
The study was not designed to diagnose anyone with Long COVID, as the participants were known to have it. And detecting the existence of a virus is not the same as diagnosing a person with a complex, multisystem disease like Long COVID, Salmon-Ceron said.
But dogs can help scientists understand more about the condition and validate patient experiences. Many long-lasting COVID patients Struggling to get proper care because they cannot prove they have COVID-19, especially if they became ill early in the pandemic, before testing became widely available.
“Nobody believed them, except for some doctors,” Salmon-Ceron said — and now some dogs.
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