Talking Animals: How do dogs sniff out diseases in humans?

We all know animals — especially dogs — have an excellent sense of smell. In many cases, dogs have able to detect diseases in people like cancer and Parkinson's disease, and possibly even COVID-19. 

Could a dog smell COVID-19? Beth Daly, anthrozoology professor, answers our question

An Ottawa police dog learns some sniffing skills in the terminal of the Ottawa airport. Dogs have been known to smell diseases in humans. (CBC)

We all know animals — especially dogs — have a refined sense of smell. 

In many cases, dogs have able to detect diseases in people like cancer and Parkinson's disease, and possibly even COVID-19

University of Windsor anthrozoology professor, Beth Daly spoke with Windsor Morning host Tony Doucette to talk about how animals sniff out diseases.

Here's a portion of their conversation:

This has come up a little bit during the pandemic because people are wondering if dogs can detect COVID-19 in people. Can they?

Well it seems they can. There is a new study going on at the University of Pennsylvania with eight dogs — Labrador Retrievers. Obviously the studies are very new. But this is a very good evidence that just like they are able to with other diseases, dogs seem to be able to sniff out COVID-19. And what's interesting is they're able to sniff it out in people who are asymptomatic. And as so many of us know, that's a good thing because we often don't know if we're asymptomatic and that's when people can often spread it unknowingly to others.

Anthrozoology professor Beth Daly talks about the ability of dogs to sniff out diseases. (Tom Addison/CBC)

What other diseases can dogs smell?

Well it's pretty remarkable. Dogs can smell an array of diseases — for instance, they are able to detect in people with epilepsy. There's some dogs that are able to predict seizures up to 45 minutes before it actually happens. They can  trigger warnings in people with diabetes that they have low blood sugar. They're also really good at detecting cancer. And there's various kinds of cancer — breast cancer, lung cancer, prostate cancer. 

If a dog does detect a disease, cancer for instance, how do we know?

Some people have reported problems with identifying dogs body language. So there was a group of researchers who were trying to isolate certain movements that the dogs made so they could say 'these are how the dog is trying to tell the humans.' But when researchers are working with animals in these kinds of disease areas they are able to recognize certain body parts or they teach them certain cues to let us know that they've detected something.

LISTEN | Tap the player to hear the full discussion with Beth Daly about animals and their noses:

I understand dogs can also help when it comes to diseases affecting agriculture? What can they do?

They're able to actually sniff out crops that have an early disease. There's several different diseases ... and they're able to let people know that the crop has this disease and stop it before it's too late and destroys all the citrus. They're also able to sniff out diseases in avocados and other plants using the same kinds of techniques.

Do other animals have the ability to sniff out disease?

There's other animals that can do non-medical diseases. We know about pigs and even dogs that sniff out truffles, and camels can sniff out water. But the African giant pouched rat is incredibly efficient at sniffing out tuberculosis, which is really great because the African rat is in Africa and that's where much of the tuberculosis is. But they are also trained as are many dogs to sniff out land mines. 


To encourage thoughtful and respectful conversations, first and last names will appear with each submission to CBC/Radio-Canada's online communities (except in children and youth-oriented communities). Pseudonyms will no longer be permitted.

By submitting a comment, you accept that CBC has the right to reproduce and publish that comment in whole or in part, in any manner CBC chooses. Please note that CBC does not endorse the opinions expressed in comments. Comments on this story are moderated according to our Submission Guidelines. Comments are welcome while open. We reserve the right to close comments at any time.

Become a CBC Member

Join the conversation  Create account

Already have an account?