A dog’s nose is around 100 million times more sensitive than a human’s, according to Science magazine, and previous studies have shown they can sniff out a variety of diseases, including cancer, diabetes and Parkinson’s disease.
The dogs come from emergency services departments in Paris and Corsica, as well as a dog training centre in Beirut, Lebanon, and had been trained for work in either search and rescue missions, detecting explosives or sniffing out colon cancer.
Researchers homed in on armpits because their smell contains a strong chemical signal indicating a possible pathogen in the body, but not the virus itself, meaning they pose “minimal or zero” risk to the animal. There have been rare cases of dogs catching Covid from humans.
The dogs were first familiarised with the odour of Covid-19 and trained to sit when they encountered it. The sweat samples were then used to soak pieces of cotton wool which were placed inside metal cones.
When sniffing these, four of the animals achieved a perfect score, while the others achieved an accuracy rate of between 83 and 94 per cent, the report said.
In one startling outcome, two of the dogs indicated a positive result for samples scientists were told had come from people not infected with the coronavirus.
“The information was immediately sent to the relevant hospital, the tests were redone and the results came back positive,” the report said. The dogs were apparently more effective than the hospital tests.