After helping in bomb and drug detection and participating in search and rescue efforts, recent studies have shown that dogs can be trained to sniff and detect COVID-19-causing SARS-CoV-2 virus in humans.
Two separate studies - one led by US researchers and one by French researchers found that dogs can be trained to detect the SARS-COV-2 virus from sweat and urine samples.
The studies were conducted at the University of Pennsylvania's School of Veterinary Medicine and at the National Veterinary School near Paris.
An earlier study conducted by Hannover's University of Veterinary Medicine had proved that dogs could detect the coronavirus in saliva samples.
Over the years, dogs have been trained to sniff out symptoms of diseases like cancer, Parkinson's, diabetes as well as oncoming epileptic seizures.
But how do they do it?
The Science Behind Dogs Detecting Diseases
Researchers trained dogs to familiarise themselves to the SARS-CoV-2's volatile organic compounds which are secreted via saliva, urine and sweat.
These VOCs give the virus a particular odour which dogs, through their heightened sense of smell, can detect.
Once the dogs were familiarised with the odour of the coronavirus, researchers then trained them to sniff out sweaty clothes of COVID-19 patients out of distractors such as clean clothes, empty cans and materials which emit strong odours like garlic and marinade.
Every time they correctly identified the diseased clothes, the dogs would be given treats.
Can Dogs Replace RT-PCR Tests?
No. For now, dogs can be used to screen possible COVID-19 positive people.
Dogs could "provide an initial screening that a laboratory test could later confirm, allowing a potentially infected person to take immediate precautions", Anna Durbin, a professor of international health at Johns Hopkins Bloomberg School of Public Health told National Geographic.
Many countries have been using dogs to screen people possibly infected by the coronavirus.
Dogs have been used since September 2020 at Finland's Helsinki-Vantan airport to screen passengers.
The Indian Army has also begun training dogs to detect coronavirus in sweat and urine samples.
These dogs have been deployed in army transit camps in north India from where troops are deployed to the border.