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It's a well known fact that looking is to humans as sniffing is to dogs. It's not that dogs' cannot see, because they can, but while we humans are visual species, dogs are olfactory. This means that while they can see, they rely more on their sense of smell to perceive. In fact, their sense of smell is one of their most useful ones to us humans. The first domesticated dogs use their dominant sense of smell to help their owners hunt, and the police dogs of today use their sense of smell to detect drugs, bombs, and buried remains. You would notice that upon getting home after a long day's work, and after your dog runs towards you with a wagging tail while jumping up and down out of excitement, it would sniff; your dog would sniff your shoes, the hems of your pants, and if you carry it, even your armpits. While you think your dog sniffs you just because it misses you, it's also actually trying to get information and form a picture of the food you ate, the interactions you've had for the day, and your health condition. How do dogs smell these information when your odor is the same everyday? Well, it isn't, apparently.
According to Stanley Coren PhD., DSc, FRSC in his Psychology Today article entitled "Why Do Dogs Like to Sniff Crotches?", like most mammals, we humans release scents through our sweat glands that vary depending on our body chemistry. The changes in our own scents may be negligible to us, but slight differences in our smell allow dogs to identify our blood sugar levels, phases of menstrual cycle in women, and even the health of our internal organs. Even though dogs are red-green colorblind, according to Coren, they have a special organ in their nose that also opens to the roof of their mouth to collect scents stronger and more precise than humans can; it is connected to an entire region in the smell-receiving area in their brain that only functions to detect, differentiate, and process smells from this small organ. The ability of dogs to identify by sniffing whether or not mammals are ovulating are very effective that the sniff test is now done by some shepherds to identify if cows are ready for breeding.
Diabetes is defined by the World Health Organization as a chronic disease brought about by the inability of the pancreas to produce insulin, or the body's inability to make use of the insulin we naturally produce. Having this problem with insulin means that our bodies experience difficulty in utilizing sugar for energy production, resulting to a high concentration of glucose in the blood. When the body of a diabetic has insufficient insulin to process sugar, it burns up fat to fuel the body's cells instead. The Diabetes Community, Support, Education, Recipes & Resources website states that an acid called Ketones is the byproduct when the body burns its own fat for energy. Ketones smell like nail polish remover, according to Lana Burgess in her Medical News Today article entitled "Why does my breath smell like acetone?", and breaths that smell like such can indicate diabetic ketoacidosis (DKA), a potentially life-threatening complication associated with diabetes.
While the smell of diabetes may not be immediately noticeable to us humans, the slightest change in a person's breath odor when the body starts producing a high amount of ketone wouldn't get past trained dogs. The special organs in dogs' nose can effectively detect these changes that indicate increase in the ketone levels, and ultimately, diabetes. The trained dogs of Can Do Canines specialize in detecting diabetes by sniffing; in the future, this method may be included in the series of tests that can improve the accuracy of its diagnosis. People who don't have access to healthcare, but are at risk of diabetes due to family history, may also benefit from trained dogs who can function as illness indicators for when a medical checkup is most necessary.
National Cancer Institute defines cancer as a genetic disease that messes up the normal cycle among cells. The normal cycle of our cells include healthy ones splitting to create new cells that make up tissues depending on our body's need for them, and damaged ones cells dying to become byproducts that our bodies excrete. Cancerous cells, however, split at an abnormally high rate forming tumors that affect its surrounding tissues and disrupt the replacement and excretion of old cells.
Although cancer research still has a long way to go, the accuracy of its diagnosis can be improved with the help of dogs. According to Joana Cavaco Silva in her Medical News Today article entitled "Can dogs detect cancer?", the powerful nose of dogs can sniff the symptoms of cancer in a person's body or bodily fluids. Silva cites an incident when a 75-year-old man's dog kept on licking a wound behind his ear. When the doctor performed diagnostic tests, he confirmed the wound to be a malignant melanoma. Trained dogs can also sniff and accurately identify the signs of colorectal cancer from people's breath and watery stool, even on its early stages. Even the odors of non-cancerous colorectal diseases do not seem to throw the dogs off from being able to sniff the odor of cancer. The same goes for lung, ovarian, and prostate cancer, according to Silva. Dogs can accurately sniff lung cancer in a person's breath, ovarian cancer from blood samples, and prostate cancer from a person's urine. The researcher cites a study where dogs trained to sniff breast cancer were also able to detect lung cancer, raising the possibility that regardless of type, cancer has an odor that dogs can detect. The use of dogs' sniffing abilities to aid in the detection and diagnosis of cancer is a low-risk and noninvasive method.
Tuberculosis, as defined by World Health Organization is a lung infection caused by Mycobacterium tuberculosis. Its symptoms include chest pain, fever, weight loss, and coughing with blood. Its speedy diagnosis has always been a problem despite the presence of volatile organic compounds that have distinct odor indicating the presence of tuberculosis.
Dr. Mona Syhre and Dr. Stephen T. Chambers detailed in their study entitled "The scent of Mycobacterium tuberculosis" the compounds they identified from the bacteria that are distinctive indicators of the presence of Mycobacterium tuberculosis. These compounds evaporate to be components of the air that tuberculosis patients exhale, and are detectable before the visual appearance of bacterial colonies. The identification of these compounds are potentially useful as basis of a non-invasive diagnostic test for tuberculosis as they have characteristic odors that can be identified by trained dog sniffers. Mika Shirasu and Kazushige Touhara stated in their The Japanese Biochemical Society study entitled "The scent of disease: volatile organic compounds of the human body related to disease and disorder" study that tuberculosis can cause breath to have a foul odor resembling the smell of stale beer. The use of dogs' sniffing abilities would allow for speedy diagnosis of tuberculosis; this can potentially save many lives as tuberculosis is one of the top ten leading causes of death worldwide according to TB Facts, and its treatment relies on its prompt diagnosis.
All dogs with a healthy nose are capable of sniffing illnesses and distinctive odors of each of its byproducts. This ability in our dogs, however, can't be maximized if they are not capable of providing feedback to let us humans know that they are smelling chemicals that are indicative of a certain illness. We cannot just assume that our pet dogs can tell us what disease we have, or if we have one to begin with. Dogs that can accurately identify odors and let humans know of the presence of a particular odor are equipped with a skillset that is not inherent to them. This skillset is developed by training, according to Kathy Santo in her American Kennel Club article entitled "How to Teach Your Dog Scent Work", through scent work; it practices the task, similar to that of working detection dogs, of locating a scent and letting humans know that a scent is present. Trained dogs that aid tests in the medical field or in the cattle farming industry have undergone professional scent work classes that many dog clubs and organizations like Can Do Canines offer. In the United States, the National Canine Division (NCD) of The Bureau of Alcohol, Tobacco, Firearms and Explosives (ATF) trains dogs and gives certification for being officially equipped with the skillset to detect explosives and provide feedback to the officers. However, the NCD only trains and certifies dogs for the purposes of law enforcement and fire investigation agencies.
Although the participation of dogs in detecting drugs, bombs, and buried remains are widely accepted and even formalized by having a special division in a government bureau, the same cannot be said about their participation in the medical field. There are many factors that have to be taken into consideration to ensure that the practice will be ethical and safe for both humans and our dogs. One example I see is the health repercussions in dogs when their powerful nose is needed in sniffing an airborne disease; although this scenario has ethical implications, it is worth recognizing that dogs' ability to smell components of diseases contributed to the discourse on how to rapidly diagnose by examining the volatile compounds. Another factor is that the reliance to the sniffing abilities of dogs as valid steps in diagnosis also has to be supported by multiple studies in various medical specialties to ensure that tests will yield accurate results. Marije K. Bomers et al. states in their study entitled "Animal Olfactory Detection of Disease: Promises and Pitfalls" that although there are successful results regarding animal training and olfactory detection using various diseases, there are still challenges to ensure that the hypothesized practice will be successfully applied in future researches. The researchers cited how the odor molecules detected by animals are currently unknown.
The research gap raised by Bomers et al. lead to attempts by research groups to detect and identify the molecules from disease specimens by working toward the development of an "electronic nose". It would aid in the detection of olfactory and volatile indicators such as distinctive odors or compounds that could lead to the low-risk non-invasive diagnosis of diseases. This is a significant development according to Tyler Berrigan in his Science News for Students article entitled "Electronic noses might replace search-and-rescue dogs", because although it is electronic, like the canine version, this electronic nose can detect odors and presence of organic chemicals. Berrigan thinks that dogs and the developed electronic noses could work together in sniffing human illnesses. In the long run, having dog and electronic sniffers as part of the early steps in diagnosis will definitely be beneficial for us humans as this will save us time and money by lessening the need for tests that have nothing to do with the diseases we actually have.
All my life I've been in love with one big friendly dopey Mastiff family member after another. No other breed has given me so much pleasure. I care about them as much if not more than most of the people I've ever known and now it's a dream to be able to research and write up everything my team and I have learned and are continuing to learn. Hope you enjoy reading about them as much as I enjoy writing :)
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