Dogs can detect virus infection by armpit scent

Dogs are able to detect the presence of Covid-19 on infected patients by sniffing their armpits, according to a new study by French scientists.

Researchers at the national veterinary school in Alfort, outside Paris, trained eight Belgian Malinois shepherd dogs to identify people infected with the coronavirus from odour samples taken from the armpits of more than 360 infected and healthy subjects.

The dogs’ overall success rate was 95%, according to a paper published on Friday on BioRxiv.org, a preprint website that posts studies that have not been peer-reviewed.

“We conclude that there is strong evidence that dogs can detect a person infected by the virus responsible for Covid-19 disease,” Prof Dominique Grandjean, who was on the team, said.

A dog’s nose is about 100million 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.

Armpit odour 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.

The others achieved an accuracy rate of between 83% and 94%.

In one startling outcome, two of the dogs indicated a positive result for samples scientists were told had come from uninfected people.

When the tests were redone, the results came back positive. —