Yahoo News Dogs can detect Covid-19 by sniffing armpits, study claims
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 subjects, both healthy and suffering from Covid-19.
The dogs’ overall success rate was 95 per cent, according to a paper published on Friday on Biorxiv.org, a preprint website that posts studies that have not been peer-reviewed.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,” said professor Dominique Grandjean, who was part of the research team.
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.
Researchers said that while impressive, the dogs’ performance could have been even more accurate if they hadn't been distracted by a TV crew and a horse that passed by the room where they were working.
Prof Grandjean said that although the study was small in scale it had provided proof of the concept that canine detection worked for Covid-19.
While more trials are required before the sniffer dogs could be widely used, the research team said the dogs could provide a quick and cost-effective way of testing in airports and other locations. “We could make the dogs available to local governments so that people can be tested without pain, for free and eventually, every day,” he told TF1.
France is not the only country looking into dog detection for Covid.
Three cocker spaniels, two labradors and a labradoodle are in intensive training at the London School of Hygiene and Tropical Medicine (LSHTM) using odour samples from Covid-19-positive patients.
If successful, dogs could be stationed at the entrances of pubs or sweep through care homes, signalling to their handlers the people who should be segregated and tested.
