The study was conducted by the University of Veterinary Medicine in Hanover, Germany, to discover whether dogs can tell the difference between a person diagnosed with COVID-19 and a person who isn’t, through their saliva.
Researchers collected test samples from two groups of people—those who had and had not been infected by COVID-19. The positive samples were taken from hospital patients who were diagnosed with COVID-19, and the negative samples were taken from individuals who had been tested to have no history of the disease.
Eight detection dogs were brought in to detect both saliva and any discharge from the respiratory system of patients with a COVID-19 infection. The dogs were first trained for a week before any actual tests were conducted.
The samples were distributed onto cotton pads, then placed in a tube. The tubes were then placed in a device that randomized the samples.
These tests were done in random order through a double-blind study, meaning the participants and individuals conducting the study do not know which sample is given to which dog.
In the results, the dogs were able to differentiate between the infected and the non-infected individuals.
“During the presentation of 1,012 randomized samples, the dogs achieved an overall average detection rate of 94 percent,” the study indicated.
When broken down, the results were that out of the 1,012 samples, 157 of them were correctly identified as being samples from infected patients, 792 of them were correctly identified as coming from non-infected individuals, leaving only 63 samples that were incorrectly identified.
Through the study, researchers found that due to the organic substances and particles discharged from patients with COVID-19, the saliva from patients diagnosed will contain certain scent markers that can be picked up by trained canines with a high rate of success.
It is generally known a dog’s nose is far more powerful than a human’s. According to VCA Hospitals, dogs assign more brainpower to interpret smells than humans do, and have far more sensory receptors than humans do. In fact, a dog’s sense of smell can be anywhere from 1,000 to 10,000 times stronger than humans.
Several studies have proven the strength of a dog’s sense of smell, and it has been used to detect the presence of cancer, malaria, and bacterial and viral infection in humans, all with a high success rate.
Different diseases, viruses, and bacterial infections give off some form of particle or compounds that come from the body, and this can be easily and quickly picked up by dogs due to their strong scent receptors.