Paris, France: Dogs can be trained to detect more than 90 percent of Covid-19 infections, even if patients are asymptomatic, according to research published on Monday, which the authors hope will change the need for new arrivals Can help Using their remarkable sense of smell - which can pick up the equivalent of half a teaspoon of sugar in an Olympic-sized swimming pool - dogs have already shown that they can smell deformities such as cancer, malaria and epilepsy.
Several previous studies have shown evidence that dogs can detect SARS-CoV-2.
Researchers at the London School of Tropical Medicine wanted to see if dogs could detect a specific odor emanating from chemical compounds associated with someone who is Covid positive but did not show symptoms.
They collected clothing and face mask samples from people who tested positive for mild or symptomatic SARS-CoV-2.
Socks samples from 200 Covid-19 cases were collected and arranged in laboratory tests for six dogs who were trained to indicate the presence or absence of a chemical compound.
Dogs need to be trained not to identify "false positives" to hack their reward system and to receive treatment even if there are no Kovid-19 samples in a given trial.
Claire Guest from the School's Faculty of Infectious and Tropical Diseases said, "This means that the dog fully understands and receives the reward for a true negative as well as a true positive."
Overall, dogs were able to successfully identify between 94 and 82 percent of the SARS-CoV-2 samples.
The researchers then modeled how effectively these success rates with traditional PCR tests could help detect mild or asymptomatic Covid-19 cases.
They found that using dogs to check arrivals at terminals such as airports could detect 91 percent of cases, resulting in 2.24 times lower transmission rates than PCR tests alone.
- 'Important start' -
The author of the research, which has yet to be peer-reviewed, said he hoped it could eventually replace the need for quarantine travelers - which necessarily disrupts every arrival, even though the vast majority are Covid. Do not be positive.
"The important thing is that the dogs are much faster than other tests," co-author James Logan said.
"What we are suggesting is that the dogs will first give an initial screening, and then those (arrivals) who were indicated as positive will receive a complimentary PCR test."
The team said that out of the aircraft loaded with arrivals - about 300 people - less than one percent were likely to carry SARS-COV-2.
Under the current quarantine rules employed by some countries, all 300 would need to be isolated, causing significant inconvenience.
But given the sensitivity of trained dogs, a maximum of 35 people on board would be described as positive, the newspaper said.
A positive PCR test of only 3 of these would be expected.
"This is a really important start and can lead to a useful, usable system," said Mick Bailey, professor of comparative immunology at the University of Bristol.
"But much more validation needs to be done before we can be assured that dogs can reliably and specifically detect asymptomatic SARS-CoV-2 infections in people in airports and train stations."
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