French scientists from the National Veterinary School in Alfort conducted a series of experiments to see if trained detection dogs can differentiate the odor of sweat produced by COVID-19 persons versus non-COVID-19 persons.
At the end of May, the charity Medical Detection Dogs planned to train specialist sniffer dogs on the current coronavirus alongside Durham University and the London School of Hygiene and Tropical Medicine (LSHTM). These dogs are already trained to recognize the scent of cancer, malaria, and Parkinson’s disease.
Dr. Claire Guest, owner of the charity said that the dogs needed to figure out how to ‘safely catch the odor of the virus from patients…in principle, we’re sure that dogs could detect COVID-19.’ Once proven, the specialist sniffers can screen even asymptomatic people. ‘This would be fast, effective, and non-invasive and make sure the limited NHS testing resources are only used where they are really needed,’ said Dr. Guest. They have high hopes as the team of canines were previously able to detect the odor of malaria with an accuracy level ‘above the World Health Organization standards for a diagnostic,’ said James Loga, a professor at LSHTM.
The new research trained 18 dogs, including eight Belgian Malinois shepherd dogs, on three different sights. The sniffed samples of the armpits from 360 participants, both infected and non-infected by the novel coronavirus with a success rate between 83% and 100%.
Professor Dominique Grandjean from the team said, ‘We conclude that there is strong evidence that dogs can detect a person infected by the virus responsible for Covid-19 disease.’
Another earlier study revealed that a dog’s nose is about 100 million times more sensitive than a human’s as they can detect severe bacterial disease and even weak thermal radiation. The smooth skin on their nose tips, called rhinarium, is richly endowed with nerves allowing them to not have just smell sensitivity, but the ability to detect body heat as well.
Mr. Grandjean’s team chose canines from emergency services departments in Paris and Corsica, and a dog training center in Beirut, Lebanon. The Belgian Malinois shepherds were explosive detection and colon cancer detection dogs.
He shared that the scientists used armpit odor samples since sweat contains a strong chemical signal indicating a possible pathogen in the body. This way, the dogs would not be exposed to the actual virus to protect the animals’ safety.
Viral genes or living strains were not detected from the infected patients. Mr. Grandjean said, ‘The likelihood of infectious transmission was minimal or non-existent.’
During the trials, each dog did between 15 and 68 identifications. The report confirmed that four of the animals achieved a perfect score, while the rest had an accuracy rate of between 83% and 94%.
On two occurrences, two of the canines indicated a positive result for samples that supposedly came from people who were not infected by COVID-19. ‘The information was immediately sent to the relevant hospital, the tests were redone and the results came back positive,’ the report said.
The results were impressive, yet the researchers said the dogs’ performance could have been even better if the media was not filming and causing distractions during the live trials. Mr. Grandjean said that although the study was small in scale it had provided proof of the concept that canine detection worked for Covid-19. More canines are yet to be trained so that more trials can be done on a larger scale.