Dogs were most likely the first domesticated animals and have been called “man’s best friend” for good reason. They are intelligent, loyal, friendly, and most importantly easy to train. Dogs have been trained to help out with several tasks right from getting the newspaper, to helping out the visually impaired as their guide dogs. Besides their well-known superpower of being extremely cute, dogs also have a super-sniffing power thanks to their sharp noses.
And we humans have made the maximum use of this ability (super sniffing, not cuteness), by training them to sniff out explosives, narcotics, and now diseases. Dog diagnosis or… let’s call it Dognosis could replace invasive methods in the future as dogs emBark on this journey from being our house pets to our Doctors.
A higher number of olfactory cells and more genes dedicated to enriching the olfactory ability is what gives dogs this super sniffing power. Humans are known to have about 5 million scent receptors, whereas dogs have almost 220 million receptors, 10,000 times more accurate than humans’. Besides, they inhale around 300 times per minute which means their olfactory cells are introduced to more odor particles. This means that a dog’s sense of smell is so powerful that they can easily detect a slight change in our body odor which could be the result of a shift in hormones or a compound released by diseased cells.
Studies have shown that dogs can detect many diseases by sniffing people’s bodily fluids, breath, or skin. Tumor cells have been shown to emit a specific odor. In the later stages, it might become strong enough for a human to be able to smell it, but dogs can pick it up at a much earlier stage. To do so, researchers have been training the canines by making them smell different samples of plasma, urine, breath, saliva, etc. After smelling more than 300 unique samples, dogs are able to distinguish between a healthy sample and a cancerous one. In a 2006 study, trained dogs could detect breast cancer with 88% accuracy and lung cancer with 99% accuracy using breath analysis. Canine cancer detection is simple and non-invasive, but it requires more investigation to be introduced to clinical practice.
Besides different types of cancer from varied samples, dogs have proved to be able to detect a few other diseases. Canines were shown to be 70% accurate in detecting the fragrance of children infected with malaria parasites from socks they had worn all night. Dogs have also been able to detect Parkinson’s disease. Parkinson’s patients have a distinct odor, even years before they develop the disease. Dogs could thus be used to detect the development of the disease at an early stage and cure individuals before the symptoms become severe. Studies have shown that dogs can detect oncoming migraines and even epileptic seizures. And it turns out that 54% of migraine sufferers with dogs noted changes in their pet’s behavior during or before their migraines. Nearly 60% of the participants said their dog had alerted them about the onset of a headache – generally an hour or two in advance. Just like the diabetic alert dogs that can smell when their handler has low blood sugar, migraine alert dogs can pick up the scent of serotonin, a chemical that skyrockets when the body is about to have a migraine. By alerting their handlers, even before they might feel any symptoms, these dogs can warn them to take preventative medication.
In a study conducted at the University of Helsinki, dogs were taught to recognize the previously unknown smell characteristic of the COVID-19 disease caused by the novel coronavirus. In just a few weeks, the first dogs were able to distinguish COVID-19 patient’s urine samples from healthy people’s urine samples almost as well as a normal PCR test. As to which substances in the urine produce the odor is still elusive. Since SARS-CoV-2 not only attacks the lungs but also damages the blood vessels, kidneys, and other organs, it can be assumed that the patient’s urine odor also changes. Dogs as a diagnostic tool could transform our COVID-19 response as they would also be able to screen anyone, even the asymptomatic cases. Along with testing and vaccines, dogs could be on the front lines to tackle this worldwide pandemic.
Although several studies have shown that dogs can effectively sniff out diseases, it may take a while for our furry friends to officially enter the medical scenario. Since researchers don’t exactly know what chemical compounds are being detected by canines, it proves to be a hurdle in training the dogs to better detect diseases. Besides, knowing what compounds dogs are noticing could also help build effective machines that could detect cancer in its early stages. However, research is still underway and Dogtors seem like a real pawssibility.
Who needs a CAT scan when we could have a Dog scan!