Dogs are well known for their sense of smell. They possess up to 300 million olfactory receptors in their noses, compared to about six million in humans. And the part of a dog’s brain that is devoted to analyzing smells is, proportionally, 40 times greater than ours. Canine sense of smell allows them to follow trails, locate lost people or detect the presence of different substances. In addition, they are even capable of identifying different diseases that affect human beings.
Given the current pandemic, could dogs help us diagnose COVID-19? Here is what current research has revealed about the ability of dogs to smell the coronavirus.
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The Canine Sense of Smell
The most important characteristic of a canine is its sense of smell. The olfactory sensitivity of dogs is much higher than that of humans, as has been shown in different studies. For example, a study published in 2011 showed that specially trained German Shepherd dogs are able to distinguish individual scents of identical twins despite the fact that they live in the same environment and eat the same food.
Due to this amazing ability they help us in many tasks such as truffle search, hunting, drug and explosives detection, search and rescue missions. Although it is a less known practice, dogs specifically trained for it, can detect certain diseases.
Although there are breeds especially equipped for this, such as bloodhounds, all dogs share this trait. This is possible because their long nose contains a labyrinth of thin bones, called turbinates, which are all lined by an epithelium. This provides a very large surface area for the air breathed to pass over. Furthermore, the olfactory center of the dog’s brain is highly developed.
Much of its brain is dedicated to processing smells. It is better than any sensor that humans have created. Therefore, it is not surprising that in this time of a pandemic, studies have been initiated to determine if dogs can detect the coronavirus.
How Do Dogs Detect Coronavirus
The canine sense of smell is so good that it allows them to detect diseases in people. Of course, it requires prior training, in addition to current advances in medicine. The olfactory ability of dogs has proven its effectiveness in the detection of diseases such as prostate, bowel, ovarian, colon, lung and breast cancers. As well as diabetes, malaria, Parkinson’s disease and epilepsy.
Dogs can smell the specific volatile organic compounds (VOC) produced by an organism in certain diseases. In other words, each pathology has its own characteristic biological imprint that the dog is capable of smelling. In addition, it can be done already in the initial stages of the disease, even before medical tests can identify that something is wrong.
When it comes to detecting biological targets, dogs are close to 100% efficiency. In the case of diabetes, dogs are able to detect rapid rises and falls of blood sugar levels up to 20 minutes before they actually occur. Diabetes assist dogs are trained to alert the person, usually by touching them in a significant way such as pawing or nudging them. Hw
How Medical Detection Dogs Are Trained?
Early detection is critical to improving the prognosis of diseases such as cancer. In the same way, anticipating blood sugar fluctuations in the case of diabetics, or detecting the onset of epileptic seizures is a very important benefit. Such detection dogs contribute to a significant improvement in the quality of life of those affected by these diseases. In addition, it helps scientists to identify biomarkers with which to later develop tests to facilitate early diagnosis.
Basically, dogs are taught to look for the characteristic chemical component of the disease. To do this, they are offered samples of feces, urine, blood, saliva or tissues, so that they learn to recognize the smells that they will later have to discern from smells associated with a specific disease. If they recognize a characteristic scent, they sit or stand in front of the sample to inform that they are detecting the specific odor. When they work with people, they usually warn them by touching them with their paw.
Training in this discipline lasts several months and, of course, is done by professionals. In view of all this scientific evidence, it is not surprising that in the current situation scientists have wondered if dogs detect the coronavirus.
Can Dogs Detect Coronavirus?
After years of experience in detecting diseases, it is not risky to entertain the idea that dogs can detect the coronavirus. In fact, researchers at the University of Helsinki have just completed preliminary tests in which they have verified this canine ability. Their results further indicate that specifically trained dogs are able to detect the disease faster and with more sensitivity than the tests that are currently being used.
DogRisk-Group Covid-19 Positive Tests Results
Dogs trained by the DogRisk research group have managed to identify the coronavirus in urine samples. At this moment they are in the phase of collecting more samples to train more dogs and determine what exactly they identify and how long that smell remains after the infection has cleared. To confirm sensitivity the researchers are including urine samples without coronavirus, but with other respiratory diseases.
Six Super Sniffers
In addition, also in the UK there is a canine team training for the detection of COVID-19. It is made up of six dogs of which three are working Cocker spaniels, one Labrador retriever, a Labrador retriever, golden retriever cross-breed, and a labradoodle. They are between 20 months and 5 years old. The goal of these trials is to train dogs to detect the smell of the virus in less than a second and to be able to do so with both symptomatic and asymptomatic patients.
To do this, they are collecting breath and sweat samples from affected people. This project is being carried out by the Medical Detection Dogs organization together with the University of Durham. They hope to finish the training in 6-8 weeks to start working directly with people. To minimize risk of infection, the dogs do not come in contact with the person it sniffs, but rather smell the air around them.
In addition to these teams, dogs are also being trained in the United States. A pilot training program utilizing scent detection dogs to discriminate between samples from COVID-19 positive and negative patients was initiated at the University of Pennsylvania’s School of Veterinary Medicine (Penn Vet).
The study will begin with eight dogs to perform detection work. Over the course of three weeks through a process called odor imprinting, the dogs will be exposed to COVID-19 positive saliva and urine samples in a laboratory setting. Once the dogs learn the odor, the investigators will document that the dogs can discriminate between COVID-19 positive and COVID-19 negative samples in a laboratory setting. These steps are necessary to establish the platform for testing whether dogs can identify COVID-19 infected people.