The success was astonishing – after a few weeks of training, the dogs could almost without fail distinguish the smell of the urine of people who are positive for the coronavirus. "It was fantastic to see how quickly they learned to recognize a new smell," said Anna Hilm-Bjerkman from the University of Helsinki, where the pilot study was conducted.
Finnish experts have announced that dogs identify the "smell of corona" as reliably as standard PCR texts that are used everywhere in the world. Additional studies and, if everything goes well, application in practice are on the way. Similar dog trainings are carried out in Great Britain and France.
It is not yet clear which substance gives urine its characteristic smell. The coronavirus doesn't just cause lung problems, it also causes damage to the kidneys and other organs, and this is believed to change the smell of urine.
They only want one scent
Dogs as disease detectors - this is nothing new. It has long been known that they can help in the early detection of various types of tumors or Parkinson's disease - before any doctor can detect it. "According to one study, dogs can recognize breast cancer with a probability of 93 percent, and lung cancer with 97 percent," says Luka Barret, who heads the German Center for Training Dogs as Assistants.
Dogs have about a million times better sense of smell than humans. While a human has about five million cells of the sense of smell, a dachshund has 125 million, and a German shepherd as many as 220 million. Dogs breathe quickly through their noses – about three hundred breaths per minute – and, in addition, distinguish scents spatially.
The most suitable breeds for this kind of training are labradors and other retrievers, cocker spaniels and various types of sheepdogs. In training, one dog is trained for only one specific smell - drugs, explosives, money, firearms or some disease.
Training takes place according to the classic reward principle. When the dog approaches a container containing, say, the sweat of a person with a certain disease, it is rewarded with food. That's how he learns to always look for that smell.
Help at airports?
Although dogs are proven helpers, like professionals more often they work for the military and the police, but rarely in medical institutions. For advocates of classical medicine and especially people from the health insurance industry, dogs are not a favorite tool.
Luka Barrett hopes that, if the findings from Finland are confirmed, the dogs will be able to help at least in places where there is a lot of human traffic, for example in front of football stadiums or at airports. "If you walk the dogs past a line of waiting passengers, they can tell the healthy from the infected," she says. Potentially infected people could then, for example, be sent for a classic test.
Also, dogs could sniff out buildings that have been vacated due to corona and then disinfected, such as nursing homes or hospitals. Then life could return there only when the dogs give the green light.
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