Cat and Dogs: seeking solutions with sniffing canines and science

Hi Mia and Julie, 

First of all, I LOVE your blog! 

After meeting at SPARCS this past summer (summer for us in North America.. I take it summer is just beginning in Australia!), I’ve followed it closely. 

You do amazing things for the promotion of  canine science. Serious love.

A bit of background for the readers: I’m currently doing my PhD at Dalhousie University in Halifax, Nova Scotia in Canada, under the supervision of Dr. Simon Gadbois. 

Dr. Gadbois has an amazing amount of knowledge and experience in the science of sniffing (just check out Gadbois & Reeve, 2014 link below!). 

He’s trained sniffer dogs for the conservation of ribbon snakes and wood turtles, to track coyotes, and to detect invasive pests in lumber. He and I have taken on a different type of project and are studying the intricacies of biomedical detection dogs, specifically, the very interesting phenomenon of Diabetic Alert Dogs. 

Cat Reeve at #SPARCS2014 where she won the 'Best Emerging Researcher' prize

I say interesting because there’s anecdotal evidence suggesting that some dogs alert their owners to hypoglycemic events (low blood sugar). In 2008, Deborah Wells published a series of case studies where dogs were reported as signalling (barking, licking, pawing etc. the individual) while their owners were awake, while they were sleeping, and even when their owners were in a different room with the door closed! And this is with no previous training! 

Isn’t this fantastic! Severe hypoglycemic events can be extremely dangerous for individuals with diabetes. If not treated, they can lead to seizures, comas, and even death. The fact that dogs may be able to alert an individual before a serious hypoglycemic event means less worry about hypoglycaemia unawareness, and blood sugar dropping over night when individuals are unconscious.

Given that dogs are signalling through closed doors, it is assumed that the dogs smell something that alerts them to a change in the physiology of their owner (as opposed to behavioural cues, as is believed to be the case with seizure alert dogs). There are many companies that have taken advantage of this supposed ability, and have trained Diabetic Alert Dogs (DADs) to sell to individuals with diabetes. 

In my own searches, I have found no company that publicly provides information as to how they train their dogs. However, according to recent studies (see Gonder-Frederick et al., 2013 and Rooney et al., 2011 below) these trained DADs dogs contribute greatly to the families of individuals’ with diabetes; they signal consistently and, consequently, significantly reduce the number of hypoglycemic events an individual experiences. 

Now, if it is in fact an olfactory cue that dogs use to identify a drop in blood sugar in their owners, one would expect that if you presented one of these trained DADs with the “scent” of hypoglycemia without the individual present (just like having the owner with diabetes on the other side of a door), the dog would still signal. 

Dehlinger and colleagues recently tested three DADs in a lab setting, presenting the dogs with human biological samples that were obtained identically to the way the samples used to train the dogs were obtained. In this study, none of the three dogs could pick out a hypoglycemic sample from a normoglycemic sample! DARN!

So what is it that these dogs smell? How is it that some DADs are accurate at signalling hypoglycaemia but evidently cannot signal in the lab? 

Enter ME! This is what I’m trying to figure out!

One possibility is that, at least in the study outlined above, the use of sweat samples was misguided. Maybe the volatiles are more strongly present in an individual’s breath. I am currently in the process of testing whether there is one channel more likely than others to expel the volatiles needed to detect a change in blood sugar, i.e. breath, sweat, or saliva. 

So far we’ve found that, after being trained to detect extremely low saliency scents, our dogs can detect and discriminate between human breath samples with incredible ease and accuracy (see the video of Koda discriminating between breath samples).