Dogs are providing crucial, non-invasive ways of detecting ailments in humans, which has led to earlier detection and changes in treatment.
Dogs, and other animals, use their sense of smell to interpret their surroundings—to detect danger, find food, and recognize family members. They rely on their nose in the same way humans rely on sight.
In most noses, air passes over turbinates. Under a microscope, a thick, spongy membrane containing scent-detecting cells covers this organ. It also has nerves connected to the brain, which analyses odors. In a human, this takes up about a square inch of space, but if the area were laid flat, it could be as much as 60 square inches in dogs, depending on the breed.
Also, the area of the brain used to process smells is about 40 times larger in a dog compared to that of a human. Scientists believe dogs are 1,000 – 10,000 times better at identifying smells than we are. A bloodhound, for example, has about 300 million scent receptors.
A new study has found dogs can identify cancer in blood samples with nearly 97% accuracy. Non-invasive and inexpensive, it represents new hope in finding cancer early enough treatment can be more successful. Detection such as this can potentially save thousands of lives every year and change how doctors treat cancer.
In the study, Heather Junqueira, lead researcher at BioScentDx, and colleagues taught four beagles to differentiate between normal blood serum and that containing cells from patients diagnosed with malignant lung cancer. One of the four, three of the dogs were able to accurately select the cancerous samples 96.7% of the time and find the normal samples 97.5% of the time.
Stopping the spread of COVID-19
Scientists have known for some time that people with illnesses have identifiable odors. Various diseases affect different parts of the body and emit unique smells. When appropriately trained, dogs have an astonishing ability to detect these airborne chemicals. In addition to some types of cancer, they have been able to sense malaria and infectious bacteria. Given this, it makes sense to use dogs to detect people who may be carriers of COVID-19.
Steve Lindsay, public health entomologist at Durham University, and collaborators at the London School of Hygiene & Tropical Medicine (LSHTM) and the U.K.-based non-profit Medical Detection Dogs, are conducting a U.K. government-funded study to test whether or not dogs can detect COVID-19. If successful, they hope dogs can be stationed in public areas such as schools and airports to provide additional detection capabilities. The University of Pennsylvania in the United States is conducting a similar study.
COVID-19 testing has been faulty with different countries experiencing varying degrees of accuracy. If it turns out dogs are capable of detecting the virus, it would mean fast, low-cost, and highly reliable screening. Early results are promising.
In France, a group used sweat samples collected from armpits and found dogs were able to detect COVID-19 infections. In a study held in Germany, researchers found dogs trained for one week could distinguish a true negative rate at an accuracy rate of 96%. Though not as accurate as rapid antigen tests, tests conducted with the dogs avoided unpleasantly, and sometimes painful, nasal swabs.
Holger Volk, the co-author of the German study and head of small animal medicine and surgery at the University of Veterinary Medicine, Hannover, used a system that rewarded the dogs with a toy or food for finding the infected samples. He believes it is a game for the dogs, a positive experience, and why they learn so quickly.
The Helsinki-Vantaa Airport is already using COVID-19 sniffing dogs as part of a pilot program sponsored by the Finnish government. There are also dogs in use at several airports in the U.A.E.
Humankind’s best friend
There is still much to learn about how dogs can detect diseases such as malaria, cancer, and COVID-19, but with the studies underway, those answers will come sooner than later. Dogs are already providing crucial, non-invasive ways of detecting ailments in humans, which has led to earlier detection and changes in treatment. These new approaches are already saving thousands of lives each year, and with more dogs trained to detect COVID-19, they can save millions more.