Sniffer dogs trained to detect virus in those without symptoms

‘Scent detection dogs could be a reasonable option for a first-line screening method in public facilities.’

DOGS could be used to sniff out people with asymptomatic Covid-19 at airports and mass gatherings, a study has found.

Ten canines used in the German armed forces have been trained to smell the coronavirus on sweat, saliva and urine.

When their noses were put to the test on 5,242 samples from people who were positive and negative for Covid-19, they were 91 per cent accurate in identifying a positive person by smelling their sweat. They were able to correctly identify 82 per cent of positive cases when smelling saliva, but were most successful when smelling urine – successfully picking out people with the virus in 95 per cent of cases.

Researchers say this detection technique could be used to quickly identify people within large groups who are positive for the virus.

The findings come after Boris Johnson’s lockdown exit roadmap revealed that up to 4,000 people would be able to gather outdoors and up to 1,000 indoors from May 17 at the earliest. Up to 10,000 people will be allowed to attend mass outdoor seated events.

This means, for example, that Wembley Stadium will be able to open with 10,000 fans attending.

The researchers say that dogs’ “extraordinary olfactory sense” means they have previously been deployed to identify pathogens and diseases from samples, and they can provide “reliable and immediate results”.

They write in the study: “Containing this global pandemic requires a high rate of testing, as an effective tool to contain viral spread.

“Scent detection dogs could be a reasonable option for a first-line screening method in public facilities such as airports or during major events as well as in retirement homes or medical institutions that would be real-time, effective, economical, effortless and non-invasive.” Sweat samples came from individuals who wiped their armpit with a cotton pad. The samples were then frozen in a laboratory at -80C (-112F) until the day of testing.

The researchers say more work is needed to establish how effectively dogs would be able to identify Covid-19 positive individuals in large crowds of people under less clinical conditions.

The study was published in the biology preprint repository bioRxiv, and is yet to be peer reviewed.