Individual dogs’ personalities, and how we interpret their behaviors, may be key to disease sniffing at scale. Billy, a floppy-eared little beagle, darts around a platform sniffing a series of holes.

Meet Jodie. Hailing from Oxfordshire, this affectionate yellow labrador lives with Caroline, her foster parent. She adores a tummy rub and isn’t fussy about who gives them to her. Jodie loves to play ...