Researchers at the University of Veterinary Medicine Hannover, Germany, found the trained detection dogs in the study could determine the difference between saliva samples from COVID-19-infected patients and those who were negative for the disease.
“During the presentation of 1012 randomized samples, the dogs achieved an overall average detection rate of 94 percent," the authors stated in the study.
The randomized controlled double-blinded trial involved eight detection dogs who were trained over one week to detect saliva or respiratory secretions of SARS-CoV-2-infected patients.
The sniffer dogs could differentiate between the samples of the saliva of infected and non-infected individuals with a fair degree of accuracy.
“One hundred fifty-seven correct indications of positive, 792 correct rejections of negative, 33 incorrect indications of negative or incorrect rejections of 30 positive sample presentations," the study authors cited.
The researchers explained that during respiratory infections like SARS-CoV-2, certain types of compounds are produced and can cause what they describe as “specific scent imprints," which can be identified by dogs trained to detect that odor.
“Dogs devote lots of brainpower to interpreting smells. They have more than 100 million sensory receptor sites in the nasal cavity as compared to 6 million in people," according to VCA Animal Hospitals. “The area of the canine brain devoted to analyzing odors is about 40 times larger than the comparable part of the human brain. In fact, it’s been estimated that dogs can smell anywhere from 1,000 to 10,000 times better than people.
"Unlike humans, dogs have an additional olfactory tool that increases their ability to smell," according to VCA Animal Hospitals. "The organ serves as a secondary olfactory system designed specifically for chemical communication.”
The study authors said these are preliminary findings and further research should be done to help develop more reliable screening methods of COVID-19-infected patients. Besides using it as an alternative to lab testing, the researchers stated this method could potentially be used in public venues such as sporting events, mass gatherings, airports to help prevent the spread of coronavirus.