The UK government has allocated a sum of over £500,000 to a specialist team of researchers who will work on finding out if dogs can detect COVID-19. The aim is to see if dogs can be trained to identify humans with the novel coronavirus before symptoms appear.
“This will establish whether they could be used as a potentially new non-invasive, early warning measure to detect coronavirus in the future,” the UK government stated.
“Bio-detection dogs already detect specific cancers and we believe this innovation might provide speedy results as part of our wider testing strategy,” UK’s Minister for Innovation Lord Bethell said.
Dogs and COVID-19: The trial
In the first phase of the trial, researchers from the London School of Hygiene and Tropical Medicine (LSHTM) in collaboration with Medical Detection Dogs and Durham University will determine if dogs are able to detect the disease in humans from their odour, even in cases where the infection is asymptomatic.
Six dogs, a mixture of labradors and cocker spaniels, will be trained to identify the infection from samples collected from coronavirus patients by NHS staff in London hospitals. If the trial gathers enough evidence, trained dogs will be used to carry out rapid screening of people coming to the UK from abroad.
But why dogs?
Dogs are already used in detecting the presence of bombs, drugs and explosives in places such as airports. As per a 2015 paper published in the Frontiers in Veterinary Science, dogs’ highly sensitive canine olfactory sensory system can detect some target substances at concentrations that are as low as parts per trillion, which is, “three orders of magnitude more sensitive than available instruments which reliably identify substances at concentrations of parts per million or billion.”
According to Medical Detection Dogs, dogs’ sense of smell is elevated due to the complex structure of their nose, which contains over 300 million scent receptors compared to over 5 million in humans. Further, it is possible that as much as 30 per cent of a dogs brain is dedicated to analysing odour.
Further, considering different diseases have unique odours, specialist dogs can be trained to detect them in humans. Over 10 years of research gathered by Medical Detection Dogs shows that dogs can screen up to 250 people per hour and can be trained to detect disease odours, which is equivalent to the dilution of one teaspoon of sugar in two Olympic-sized swimming pools. Therefore, for a highly infectious disease such as COVID-19, training dogs to detect the disease can screen scores of individuals with rapidity.
Professor James Logan, lead researcher for the work and Head of the Department of Disease Control at the LSHTM, said, “Our previous work has shown that malaria has a distinctive odour, and with Medical Detection Dogs, we successfully trained dogs to accurately detect malaria. This, combined with the knowledge that respiratory disease can change body odour, makes us hopeful that the dogs can also detect COVID-19.”
How do dogs detect odours?
Tissues infected with pathogens release unique volatile biomarkers that become a part of a disease’s volatile organic compounds (VOCs) signature. These VOCs that are emitted from the human body in exhaled breath, urine, sweat or faeces may reflect the metabolic condition of the individual. When infected by an infectious or metabolic disease, this odour changes, which trained dogs may be able to detect. According to a review published in the Journal of Biochemistry, disease-specific VOCs can be used as diagnostic olfactory biomarkers of infectious diseases, metabolic diseases, genetic disorders and other kinds of diseases.
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Therefore, dogs can be trained to detect these biomarkers using their olfactory sensory system. According to the aforementioned 2015 paper, in some cases, dogs have been able to detect diseases from exhaled breath, which has the lowest known VOC concentrations.
Which other diseases can dogs detect?
Past research has established that dogs can be used to detect diseases such as malaria, prostate cancer, diabetes, Parkinson’s disease and breast cancer. Medical Detection Dogs is working with researchers from the Imperial College London to detect the odour of specific bacteria.
In the case of Parkinson’s disease, UK researchers are working on a study to determine if dogs can detect the disease, possibly years before the onset.
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