Duchess of Cornwall has hailed trials teaching dogs to sniff out coronavirus as a "game changing moment" which will "save thousands of lives".Camilla, wearing a plastic visor for the first time in public for parts of her engagement, visited the Medical Detection Dogs charity in Milton Keynes on Wednesday, September 9.She appealed for more volunteers and for all hospitals to provide the organisation with positive coronavirus samples to speed up the vital research.It is hoped Covid-19 detecting dogs could be on duty at airports by Christmas.The duchess said: "From the minute I visited you, I just knew that there was something very special about these dogs and as we've seen today with Covid, how quickly they're learning to sniff the scent."It.