Dogs can be trained within weeks to detect a COVID-19 infection, with a degree of accuracy comparable to a nose and throat swab test, according to new research.
Four dogs were trained to sniff out the virus in spring 2020 as part of a study led by the University of Helsinki in Finland.
The animals, previously trained to detect drugs, dangerous goods, or cancer, each sniffed skin samples from 114 people who had tested positive for the virus and from 306 who tested negative.
They were able to detect the virus with 92% accuracy, the study found.
The dogs also participated in a trial where they sniffed the samples of 303 incoming passengers at Helsinki-Vantaa International Airport between September 2020 and April 2021.
They correctly identified negative samples in 296 out of 300 negative tests, and identified three positive cases as negative.
It is among a number of studies looking at the ability of dogs to detect COVID-19 – a clinic in Germany has trained dogs to detect the virus in human saliva, while a study in Thailand trained dogs to detect a volatile organic compound secreted in the sweat of sufferers.
Scientists have said that using dogs to sniff out viruses could be especially valuable in the early stages of a pandemic when other options are not available.
But they could also help to contain an existing pandemic.
Writing in BMJ Global Health, the researchers suggested “dogs could be used both in sites of high Sars-CoV-2 prevalence, such as hospitals (to pre-screen patients and personnel), as well as in low prevalence sites, such as airports or ports (to pre-screen passengers)”.
The dogs were less successful, however, at identifying the alpha variant, as they had been trained to detect the wild type.
The researchers said: “This observation is remarkable as it proves the scent dogs’ robust discriminatory power.
“The obvious implication is that training samples should cover all epidemiologically relevant variants.
“Our preliminary observations suggest that dogs primed with one virus type can in a few hours be retrained to detect its variants.”