One fine Saturday afternoon I was sent off by my daughter to take her laidback red-heeler dog Zoe for a walk.  

We wandered down to an off-leash area in a shallow backwater of the Brunswick River. Zoe was enjoying a paddle in the clean sand shallows of the salty rising tide. It was all very relaxing and I must have been daydreaming because suddenly and unexpectedly, my reverie was cut short by a shrill scream from someone close by, also standing in the shallows.  

I then saw that the usually placid Zoe was intently sniffing a woman’s leg. I whistled her but the dog took no notice. That was unusual. Even stranger, the lady showed no intention of backing away. She just seemed immobilised in a state of existential terror. I waded across to get the dog and to reassure her there was no danger. I do understand that not everyone loves dogs.

‘Oh no,’ she lamented, ‘It’s not that. If a dog sniffs a person, it can smell cancer. I must have cancer’. 

I felt I had to reassure her. As a doctor who had a lot of contact with alternative communities, I had heard of just about every bit of health mumbo-jumbo there ever was- but this dog smelling cancer thing? Never. Quietly now, she rebuked me. ‘That’s how my aunt discovered her cancer. It’s very well known that dogs can smell cancer’.


I couldn’t leave it at that and with our feet still immersed in the softly rising seawater, I decided to give her some free medical advice. If she believed this myth so strongly, it might be a good idea to see her doctor and to request a full-body CAT scan, which might detect asymptomatic cancers. That seemed like a plan and we parted the shallows in peace.

Later on when I saw my daughter to hand over her dog, I told her of this strange incident. Showing wit beyond her years she replied, ‘Maybe Zoe did her a favour and saved that lady’s life, Dad. She’s just had a DOGSCAN. Now you are sending her for a CATSCAN.’ Even better, she could have a PETSCAN, I was able to add. 

Superior Sense of Smell

Since that day, I have tuned into stories and found articles about dogs detecting disease with their superior sense of smell. It seems to be a serious business.

Dogs have an amazing sense of smell. By nature they inhabit a complex layered aromatic world about two feet off the ground, always sniffing things. The messages left on certain trees and posts must be very fascinating indeed and analysis can be quite time-consuming, enough to test the patience of any dog walker.

Training Dogs

But can dogs be trained to use this talent? Customs at airports have been using dogs for years. They scan a lot of bags very quickly for whatever they have been trained to find, be it drugs, fruit or smuggled wildlife.

It does not follow that every sniff of a leg from a random dog means cancer. Dogs can build a complex memory bank of aromas. For example, I met an old dog friend after several years. At first, he was indifferent, then started sniffing my leg. It took about a minute for his brain’s light to come on, then he was jumping in joyful recognition.

Training the Key

This is all very well, but for consistent results, training has to be the key. Some breeds are specialised in these skills. A trained bloodhound can pick up the scent of a missing person from the smell of a shirt. A Jack Russell can find and destroy a rat in hiding, but a schnauzer won’t even bother with any of it.   

As for the lady who paddled, I never did hear the final result, but curiosity led me to the Bill and Melinda Gates Foundation, which is funding the training of dogs for early detection of malaria in humans, by smelling the patients’ breath.

As to whether dogs can detect cancer, everyone can decide for themself. Check out cancer detection.

Finding Covid?

In addressing Humanity’s immediate need, I wonder whether man’s best friend could help us in our current COVID pandemic. It seems a longbow to draw, that a suitable dog could rapidly move through a gathering of humans, to detect and signal a specific virus. To my surprise, I found some information on the subject. 

We might get a new test DIDOC, or Dogs in Detection of COVID. 

David Miller

(David is a retired medical doctor who writes on travel and health.)

(Researchers are running an Helsinki test scheme and say apparently dogs can identify a virus in seconds. Ed)

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