Dog Detectors

Pessimistic dogs may be better sniffersand other pointers for smelling out disease

- Rohini Subrahmanyam

BILLY, A FLOPPY-EARED LITTLE beagle, darts around a platform sniffing a series of holes. Each hole contains a used surgical-type mask bearing a different human's distinct mix of scents. But her sharp nose is hunting for just one such combination: the one that signals cancer.

Cancer can change a person's “volatilome,” the unique set of volatile organic compounds found in breath, sweat, blood and urine. Billy and her cohort have learned to sniff out these subtle scent cues in masks worn by people with cancer diagnoses. Researchers are also studying how dogs can detect diseases such as COVID and malaria, as well as psychological conditions, including post-traumatic stress disorder.

Scientists discovered dogs’ powerful disease-smelling skills in 1989, when a dog detected cancer in its handler. But clinicians still do not routinely use dogs for diagnosis. Besides the obvious logistical challenges, dogs vary greatly in their olfactory accuracy. Researchers are increasingly finding that disease-sniffing prowess may come down to individual dogs’ personality—and how well their handlers know them. New research efforts are focused on figuring out which dogs would be best for the job and on interpreting dogs’ behaviors during a smell test.

Sharyn Bistre Dabbah, a veterinary scientist now at the University of Bristol in England, set out with colleagues at the U.K. charity Medical Detection Dogs to learn how the animals’ personalities—especially their level of optimism or pessimism—affect diseasedetection skills. Their results appeared recently in PLoS One.