It is said that the dog is the best of man and there are certainly studies that support it: it reduces the levels of stress, keeps its older owners active and helps them socialize. Now, these animals add another task in their help to humanity: preventing the spread of covid-19 thanks to your sense of smell.
THE worked conducted by researchers from Universitary hospital (HUS) and the University of Helsinki (HU) ensures that sniffer dogs can accurately detect airport passengers infected with SARS-CoV-2. The research was published in the open access journal BMJGlobal Health.
Preliminary data suggest that dogs, trained for a few weeks, discover the virus with an accuracy comparable to that of PCR, the most popular technique to date for finding infected people.
Previous articles already pointed out how dogs are able to detect different volatile organic compounds released during metabolic processes in the body, including those generated by bacterial, viral and parasitic infections.
Experts suggest that their help can be especially useful both for monitoring patients in the early stages of future epidemics –in the absence of other resources– to contain pandemics that are already underwaysince these mammals have a very keen sense of smell and can pick up odors at very low levels, so they can surpass any mechanical technique available today.
Training dogs to save lives
The researchers trained four dogs to screen for SARS-CoV-2 in spring 2020 in real-life situations. Each of them had been previously trained to look for illicit drugs, dangerous goods or even, Cancer.
First, to test your detection skills 420 volunteers provided skin samples. After performing a PCR, 114 tested positive for SARS-CoV-2 and the rest negative. Samples were randomly presented to each animal during seven testing sessions.
In general, the diagnostic accuracy of all sniffed samples was 92%, both to detect those who had the infection (sensitivity) and those who did not (specificity).
In the second phase of the study the dogs were launched at the International Airport of Helsinki-Vantaa (Finland), between September 2020 and April 2021. The results of PCR and trackers coincided in 98% of the samples taken in the airport.
Those responsible for the study suggest that “these trained animals could be used both in places of high prevalence of SARS-CoV-2, such as hospitals, and in places of low prevalence, such as airports or ports to save time and resources.” .
Study limitations
Of course, the researchers caution that dogs trained to sniff out other substances could confuse them with SARS-CoV-2. Likewise, “the necessary storage period of the volunteer samples for the initial training may also have affected the viability of the volatile organic compounds”, they comment.
On the other hand, a key finding was that dogs had less success in identifying the alpha variant of the virus, since they were trained to detect the primary variant. For the authors, “this observation is significant, as it demonstrates the discriminatory power of the triggers”.
“Our preliminary observations suggest that these animals taught with a specific variant of the virus can be retrained in a few hours to detect the rest,” they conclude.