AAccording to two preliminary studies published this month, dogs trained to detect signs of SARS-CoV-2 infection can almost instantly display positive samples with greater than 90 percent accuracy. While such rapid results do not replace the established PCR test to confirm infection, puppies could offer “a convenient method for mass screening,” said James Logan, an infectious disease researcher at the London School of Hygiene & Tropical Medicine co-author of one of the studies, tells the BBC.
Logan and his colleagues trained Asher, Kyp, Lexi, Marlow, Millie, and Tala to alert their handlers if they smelled SARS-CoV-2 infection on an infected person’s clothing. According to The guardEvery dog communicates a positive test differently: Millie sits and moans when she gets a scent, Tala wags her tail while others stand completely still.
In the study, published as a preprint, their sensitivity – or ability to accurately highlight positive samples – ranged from 82 to 94 percent. The guard notes that PCR tests have a sensitivity of about 97 percent and lateral flow tests – rapid tests that use antibodies to pick up virus particles – have a sensitivity of 58 to 77 percent. The specificity of the dogs – how well they accurately identified negative samples – ranged from 76 to 92 percent.
Another study had 335 human participants, 109 of whom tested positive for SARS-CoV-2 from a PCR test, wiping their armpits with a cloth and placing them in a glass. Nine dogs trained to report positive samples had a sensitivity of 97 percent and a specificity of 91 percent France Bleu. The results were shared last week by the Alfort National Veterinary School in France.
Using electronic sensors, Logan’s team analyzed the volatile organic compounds in samples from infected and uninfected participants and confirmed that the virus creates a specific odor profile that is believed to be ingested by the dogs’ snouts.
According to the Associated Press, some countries have already used canines to detect SARS-CoV-2 infections. In Thailand, for example, Labrador Retrievers trained at Chulalongkorn University examine samples with an accuracy of 95 percent – except when it’s just before dinner. “5pm is your mealtime. If it’s around 4:50 a.m., they’ll be distracted. So you can’t really let them work anymore. And we can’t let them work after dinner because they need a nap, ”says Kaywalee Chatdarong, the research team leader, the AP. “They are living animals and we need to consider their needs and feelings.”