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Dogs and Disease

We have previously talked about how dogs can detect COVID-19 (you can check it out here) and how they are amazing animals with a superior sense of smell. Other than the coronavirus, how can dogs be used in the medical field? 

How does a dog's nose work? 

Human noses are just fine  they have five million olfactory receptors; however, dogs have 300 million! In this way, they can detect more chemicals and more odours in the air. Even though dogs' brains are smaller than those of humans, the area in their brains devoted to smell is 40 times larger than in humans.

A dog's nasal cavity is divided into two separate chambers and opens into two nostrils that can wriggle and take in smells independently. As a dog sniffs, particles and compounds are trapped by mucus. Some of the air goes to the lungs, and some of them go to the brain, where they may be recognized. Dogs inhale through the openings of their nostrils and exhale through slits at the side. This allows them to locate the direction of the smell. You can find more information about this topic at this TED Talk

Anatomy of a dog's nose (Província Studio via YouTube)

Medical Alert Assistance Dogs

Medical alert dogs can warn their owners about impending crises in a various illnesses, including diabetes, heart disease, airborne allergies, asthma, and many others.

Diabetic Alert Dogs

A typical example of Medical Alert Assistance Dogs is diabetic alert dogs, trained to alert diabetic owners when there are chemical changes in their blood, as they may lead to complications if left untreated. Dogs can do this as there are distinct odours that accompany different blood sugar levels.

Cancer-Detecting Dogs

Many research studies have focused on how dogs detect cancers as they leave specific traces in a person's body and bodily secretions. Cancer cells, or healthy cells affected by cancers, produce and release these odour signatures, which may be picked up by dogs' olfactory receptors. A particularly interesting study shows that dogs trained only to detect breast cancers also react to melanoma and lung cancers, indicating that there may be a similar odour pattern to different types of cancer. If you're interested, you can read this article showcasing this type of Medical Alert Assistance Dog.

Nut Allergies

Some people may be placed in a life-threatening situation just by breathing in airborne nut allergens. Some dogs are trained to detect airborne allergies in the environment and alert the client before they contact allergic triggers. Check out how amazing these dogs are in this Youtube video.

How are dogs trained?

Medical alert dogs receive specialized training based on the targeted specific condition of their owner. For example, during diabetes alert dogs training, a sample of the applicant's saliva will be used when their blood sugar is at 70 mg/dL. In all medical situations, dogs are trained to react in a specific way, such as tapping the owner to alert them. In general, it takes about two years for trainers and owners to train their dogs, depending on the dog's age, breed or training level.

Dogs are amazing animals that can be a companion and an assistant. Although dogs cannot replace hospital testings, they can be reliable helpers in detecting COVID-19 and numerous types of medical conditions. Some people’s lives may even depend on their fluffy four-legged animals sitting next to them.


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Yoel, U., Gopas, J., Ozer, J., Peleg, R., & Shvartzman, P. (2015, September). Canine Scent

Detection of Volatile Elements, Characteristic of Malignant Cells, in Cell Cultures.

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Featured image courtesy of Helena Lopes via Pexels

Article Author: Michelle Lam

Article Editors: Valerie Shirobokov, Stephanie Sahadeo