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COVID-19 dog Asher

Asher may just look like a cute cuddly dog but he is much more than that. He, along with some of his canine friends, have been trained to sniff out Covid-19 in people and the initial results show they can do it very reliably.

This is because a research team, involving Durham, has found that Covid-19 has a very distinct odour – which we as humans can’t smell – but the dogs’ super sniffing powers can detect it with up to 94 per cent accuracy.

Powerful noses

The study, which is not yet peer-reviewed, is the most extensive of its kind to date using over 3,500 odour samples donated by the public and NHS staff. It involved training dogs to distinguish between infected and uninfected people alongside odour analysis and modelling.

The dogs were able to detect odour from individuals with Covid-19 regardless of whether they had symptoms or not, as well as those with two different strains, and with both high and low viral loads.

Although the dogs were trained in a trial setting and more work is needed to transfer the method to real-world locations, the preliminary results show that specially trained dogs can rapidly, non-invasively sniff out Covid-19.

The study is a collaboration between the London School of Hygiene & Tropical Medicine (LSHTM), Medical Detection Dogs and Durham University.

Rapid screening

In addition to the dogs training, the team also carried out mathematical modelling to assess the effectiveness of using dogs as a Covid screening method. This modelling shows the potential for dogs to be used at ports of entry such as airports, estimating that two dogs could screen 300 plane passengers in around 30 minutes as part of a ‘Rapid Screen and Test’ strategy.

Use of the bio detection dogs plus a confirmatory PCR test are estimated to detect more than twice as many cases and prevent more onward transmission than isolating symptomatic individuals only.

Super sniffers

The dogs were trained to identify Covid-19 using body odour samples from masks, socks and t-shirts, with 3,758 samples sent in.

The study also included a crucial so-called double-blind trial where the dog, technician and dog trainer were not aware which samples were positive or negative, removing any risk of inadvertent bias or cues.

The team now hopes to move on to the next phase of the trial which will involve the dogs detecting Covid-19 directly on people in real-world settings such as airports.

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