Trained dogs that are usually used to seek out drugs and contraband are being trialled to sniff out Covid-19. The Government has funded new research, which if successful, could be used as a quick and non-invasive way to test for the virus. How does it work? The dogs are trained to recognise the scent of Covid-19, using masks and socks from volunteers. They are trained using a carousel of different smells, and rewarded when they sit down by the correct port. This method of using dogs to sniff out disease is already widely used for malaria and some cancers.