Dogs can be trained to detect more than 90% of “Covid-19” infections, even when patients are asymptomatic, according to new research available in preprint.
And by using their wonderful sense of smell, dogs have already shown that they can smell diseases like cancer, malaria and epilepsy.
Several previous studies have shown proof of concept that dogs can detect SARS-CoV-2.
And researchers from the London School of Tropical Medicine wanted to know if dogs could detect a distinct smell emitted from chemical compounds associated with a person infected with “Covid” virus, but not showing symptoms.
They collected samples of clothing and face masks from people who had tested positive for mild or symptomatic SARS-CoV-2.
Socks samples were collected from 200 cases of “Covid-19”, with their arrangement in laboratory tests of six dogs that were trained to indicate the presence or absence of the chemical compound.
The dogs needed to be trained not to identify “false positives” in an attempt to penetrate the reward system, and to obtain rewards even if there were no “Covid-19” samples in a particular test.
“This means that the dog fully understands and is rewarded for a correct negative as well as a correct positive,” said Claire Guest, from the College of Infectious and Tropical Diseases.
Overall, dogs were successfully able to identify between 94 and 82% of SARS-CoV-2 samples.
Then the researchers modeled how effective these success rates were, along with traditional PCR tests, in detecting mild or asymptomatic COVID-19 cases.
They found that using dogs to screen arrivals at stations such as airports could detect 91% of cases, resulting in a transmission rate 2.24 times lower than PCR tests alone.
The authors of the research, which has not yet been peer-reviewed, said they hope it will eventually replace travelers’ need to be quarantined – which necessarily disrupts all access even though the vast majority are not positive.
The team said that out of a plane full of arrivals – about 300 people – it was statistically likely that less than one percent had SARS-CoV-2.
Under the current quarantine regulations used by some countries, everyone will need to be isolated, which causes great inconvenience.
“This is a really important start and could lead to a useful and usable system. But there is a lot more to do to validate health before we can be confident that dogs can.” Specifically to reliably detect asymptomatic SARS-CoV-2 infection in people at airports and train stations. ”
Source: ScienceAlert