Dogs could be trained to discern COVID-19 in humans, reported researchers from The London School of Hygiene and Tropical Medicine (LSHTM), Medical Detection Dogs and Durham University in a podcast last Wednesday. The study has received £500,000 from the UK government and hopes to be able to train dogs for rapid virus detection in airports and other ports of entry. 

The work builds on previous malaria research, which successfully trained dogs to detect malaria in people based on its characteristic odour.

Over 10 years ago, anecdotal evidence suggested that dogs could detect cancer in urine samples, leading to formal studies that confirmed the theory. Ever since, dogs have been used to detect a wide range of conditions – including bladder cancer, but also rapid changes in blood sugar levels in advanced diabetics.

Dogs are an ideal candidate to detect subtle smells because their sense of smell is highly developed. They have over 350 million olfactory receptors, allowing them to sniff out a teaspoon of sugar in the volume of water held in two Olympic-sized swimming pools, said researchers at the podcast. Another advantage of using dogs is that they are used to working alongside humans and are ‘highly trainable’- their use is already widespread in security programs and agriculture, among other uses.

Dogs could also screen up to 250 people an hour, said researchers. But if dogs were used in the future to detect COVID-19, they would not replace swab tests or antibody tests; rather, they would augment the testing capacity in specific locations. The team is looking to scale up the venture and apply it to other countries, if it proves to be successful. 

The study on malaria detection — which used foot odours from socks worn by Gambian children, that dogs could detect at a high accuracy — provides a template for the COVID-19 study and could help “prevent a second wave by identifying people from high-risk countries at ports of entry”. 

In the case of COVID-19, dogs will be given samples from face masks or the feet of people with COVID-19, as well as placebos, and researchers will evaluate whether the dogs can recognise COVID-19 odours, which they will communicate to researchers through physical gestures. The samples collected will also be analysed in laboratories to identify whether there are volatile biomarkers associated with COVID-19 infection. 

If there are odours associated with COVID-19, dogs could take about eight weeks to train, before practicing in more realistic scenarios.

Currently, six dogs (cocker spaniels, retrievers and mixes) are being trained to identify the odours of COVID-19. These dogs are experienced bio-detection dogs as well as assistance dogs that monitor the health of people with life-threatening diseases. 

Image Credits: MDD/BexArts/Nigel Harper.