Detecting the scent of sickness
Arecent column focusing on registered therapy dogs that provide emotional support and companionship to those in need led a reader to wonder about another canine talent: The ability to detect disease in humans.
Many pet owners are aware of their critters’ abilities to sense when humans are feeling poorly physically and emotionally. The effect of having a fuzzy four-legger crawl onto the lap of someone suffering from illness or distress is incredibly comforting and demonstrably helpful; according to Harvard Health (health.harvard.edu), several studies have shown that dog owners have lower blood pressure than non-owners, and blood pressure goes down when a person pets a dog.
That’s just the tip of the iceberg. Along with this seemingly natural skill, dogs can be trained to suss out sickness, possibly including the presence of covid-19 in those who are infected.
According to research scientist Glen Golden of Colorado State University, some animals—dogs, rodents, and carnivorous mammals such as weasels, otters and ferrets—have highly functional nerve cells that respond to odors.
“When one of these animals detects a meaningful odor, the chemical signal is translated into messages and transported throughout its brain,” Golden writes for website The Conversation, which offers analysis, research and commentary on issues affecting our world.
“The messages go simultaneously to the olfactory cortex, which is responsible for identifying, localizing and remembering odor, and to other brain regions responsible for decision-making and emotion. So these animals can detect many chemical signals over great distances and can make rapid and accurate mental associations about them.”
Dogs have been employed to detect breast cancer and lung cancer by sniffing the breath of patients, bladder cancer and prostate cancer by sniffing patients’ urine, colorectal cancer by sniffing patients’ exhaled breathing and stool samples, ovarian tumors by sniffing patient tumor samples and blood samples, and cervical cancer by sniffing patient biopsy samples, according to information supplied by Roswell Park Comprehensive Cancer Center in Buffalo, N.Y. (roswellpark.org).
Researchers at Medical Detection Dogs, a registered charity in England and Wales that trains Medical Alert Assistance Dogs to detect minute changes in an individual’s odor triggered by disease and alert them to an impending medical event, believe that dogs could play a part in preventing further spread of the coronavirus.
Its website medicaldetectiondogs.org.uk reports that dogs searching for covid-19 would be trained in the same way as dogs already trained to detect diseases like cancer, Parkinson’s and bacterial infections: by sniffing samples in the charity’s training room and indicating when they have found it. They are also able to detect subtle changes in temperature of the skin, so could potentially tell if someone has a fever.
Once trained, dogs could also be used to identify travelers entering a country infected with the virus or be deployed in other public spaces. Claire Guest, CEO and co-founder of Medical Detection Dogs, says: “In principle, we’re sure that dogs could detect covid-19. We are now looking into how we can safely catch the odour of the virus from patients and present it to the dogs.
“The aim is that dogs will be able to screen anyone, including those who are asymptomatic and tell us whether they need to be tested. This would be fast, effective and non-invasive.” James Logan, head of the Department of Disease Control at the London School of Hygiene and Tropical Medicine and director of Arthropod Control Product Test Centre, said, “Our previous work demonstrated that dogs can detect odors from humans with a malaria infection with extremely high accuracy, above the World Health Organization standards for a diagnostic.
“We know that other respiratory diseases like covid-19 change our body odor, so there is a very high chance that dogs will be able to detect it. This new diagnostic tool could revolutionize our response to covid-19 in the months to come, and could be profoundly impactful.”
If the research is successful, said Steve Lindsay, a public health entomologist at Durham University in Durham, England, “we could use covid-19 detection dogs at airports at the end of the epidemic to rapidly identify people carrying the virus. This would help prevent the re-emergence of the disease after we have brought the present epidemic under control.”
So it seems that dogs not only can make us happier; they are also capable of making us healthier.