Jun 15 / Dr Fenella Eason

The scent of Covid-19: canine-human collaboration in early detection of coronavirus

The shadow of Covid-19 still looms darkly over continents, compelling new research and investigation to assist in early diagnosis and treatment of this severely infectious and sometimes fatal illness. Innovative canine-human collaboration – between the dogs and staff of the charity Medical Detection Dogs (MDD), and researchers from the London School of Hygiene and Tropical Medicine, and Durham University – has initiated a project that may enable each trained dog to screen approximately 250 people per hour for symptoms of Covid-19 infection.

In four years spent observing the close relationships forged between MDD diabetes alert dogs, their trainers, and individuals living with Type 1 diabetes (Eason, 2019), I became familiar with the dogs’ extraordinary olfactory ability to detect not only changes in blood glucose levels in people with diabetes, but also changing odours in patients with certain cancers, Parkinson’s Disease, malaria and bacterial infection. Symptoms or alterations in health may not be visible or detectible to an unwell individual or medical diagnostician, but reveal their presence to trained dogs in breath or urine samples; early, non-invasive detection can lead to preventative medical measures being taken to inhibit illness development and that can more swiftly improve the path to better health.

Like many other animals with keen scenting ability – pigs, turkey vultures, giant pouched rats, for example – dogs’ noses have acute sensitivity to odour. Beneficial to their species in accurately detecting nutrition or best mate, or alerting to approaching enemy, toxic danger or environmental hazard, dogs’ olfactory superiority is also highly advantageous to humans in identifying change in volatile organic compounds from breath, urine or faecal samples. Their accuracy may be estimated by considering that they can detect the equivalent of a teaspoon of sugar in two full Olympic-sized swimming pools. MDD diabetes alert dogs are able to warn their hypo-unaware human companions of an imminent hypoglycaemic episode up to an hour before dizziness, confusion and possible fall into unconsciousness occur, so there is time for their human partner to find a safe and hygienic area to conduct a blood test and remedy low blood sugar levels.

In Covid-19 training, six dogs (several from rescue centres or other charitable organisations) will work with body odour samples, collected by NHS researchers and made non-infectious before dogs and trainers are exposed to them. Covid-19 detection dogs will be able to passive screen i.e. no physical contact will occur between the MDD dogs and any individual, ‘including those who are asymptomatic’; they will indicate to their handlers whether they detected the virus’ (Medical Detection Dogs, 2020). This would then be confirmed by a medical test. It is hoped that, once successful testing on samples has been completed, the dogs would move on to practical testing of their passive screening ability, and be deployed with their handlers in ‘in theatre’ testing (Medical Detection Dogs, 2020). If the project is successful, trained Covid-19 detection dogs could soon be working in similar environments to drug or explosive detection dogs, at airports and sports events or wherever there are large mobile congregations of people.

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Around the world, researchers are now working with dogs in rigorous scientific trials to discover whether they can accurately detect and indicate the presence of Covid-19 in symptomatic and asymptomatic patients. At the University of Helsinki, Finland, Anna Hielm-Björkman reported ‘dogs could see that a person was getting sick about four to five days before they got the disease’, signifying dogs’ sensitivity was better than traditional tests (Cremer, May 2020). Cremer also noted that current Covid-19 testing gives results in two to three days, but that results from the dogs were immediate.


Cremer, J., 2020. Dogs sniff out coronavirus ‘far better than machines or tests’, Cornell Alliance for Science, 27 May 2020. Accessed 9 June 2020 https://allianceforscience.cornell.edu/blog/2020/05/dogs-sniff-covid19/

Eason, F., 2019. Human-canine collaboration in care: doing diabetes. Routledge.

Medical Detection Dogs, 2020. How will Covid-19 dogs be able to help? Accessed 14 June 2020 https://www.medicaldetectiondogs.org.uk/how-will-covid-19-detection-dogs-be-able-to-help/
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