Bravo, a Labrador Retriever, sits in front of a sample of human sweat after detecting the COVID-19 coronavirus at a mobile canine unit in Bangkok, Thailand, Thursday, June 17, 2021. Thailand has deployed a canine virus detection squad to help provide a fast and effective way of identifying people with COVID-19 as the country faces a surge in cases, with clusters found in several crowded slum communities and large markets. (AP Photo/Sakchai Lalit)