An ongoing dialogue on HIV/AIDS, infectious diseases,
March 15th, 2016
Dogs Again Are Brilliant Diagnosticians
The reputation of dogs in the ID world got a big boost when Dutch researchers published this remarkable study of Cliff — a beagle who was trained to “diagnose” C diff using his superior olfactory abilities.
(A couple of entertaining videos here, if you can’t get enough of this stuff. I can’t.)
Now, in the pages of Open Forum Infectious Diseases (IDSA’s open access journal, of which I’m editor), we’ve published another landmark study demonstrating the extraordinary sniffing powers of our best friends:
From the paper:
In this double-blinded case-control validation study, we obtained fresh urine samples daily in a consecutive case series over 16 weeks. Dogs were trained to distinguish urine samples that were culture-positive for bacteriuria from those of culture-negative controls, using reward-based clicker/treat methods …Dogs detected urine samples positive for 100,000 cfu/mL E. coli (N=250 trials; sensitivity 99.6%, specificity 91.5%).
Impressive! Not only that, but the pooches did equally well with other bacteria — Klebsiella, enterococcus, Staph aureus. An anecdote in the Discussion section of the paper highlighted the real-world performance of Abe (he’s a dog) when a sick person visited the training center — I encourage you to read the full paper (which is on OFID’s early access page) for the details. Not only that, but there’s an action shot of the experimental methods.
So how do the dogs do so well at this task? To start, it is estimated that a dog’s nose is over 100,000 times more sensitive than ours. Plus, there’s this astute comment from my Twitter feed:
Indeed, this diagnostic task is right in the “sweet spot”, as it were, of a dog’s abilities. As the paper notes, “Sniffing urine is innate behavior in dogs.”
Practice makes perfect. Woof!