Covid-19 sniffer dogs, an opportunity not to be sniffed at?
Yes. Sniffer-dogs have been trained, using samples of sweat from flight passengers, placed in sterilised containers, to detect Covid-19. When presented with these containers, the dogs sit down or paw the ground if they identify molecules produced by SARs-CoV-2. So far, trials have been carried out, using passenger samples, at arrival areas in airports in Finland, Lebanon and the United Arab Emirates.
The passengers who had samples tested by dogs were then retested using conventional tests. The trial results show that the dogs identified SARS-CoV-2 days before conventional testing spotted the virus. This suggests that they can spot the viral infection at its earliest stage and identify asymptomatic carriers.
Are special dogs required for this?
Yes and No. A wide variety of breeds have been used for this task including greyhounds, cocker spaniels, labrador retrievers, golden retrievers, Belgian malinois, German shepherd dogs and border collies.
However, seemingly some dogs like sniffing more than others, and the important quality in a sniffer dog is a love of sniffing, according to dog trainers in Helsinki that carried out trials at the city’s airport. Most of the dogs trained for airport trials had already demonstrated their love of sniffing by identifying diseases, atmospheric mould and bed bugs in clinical settings.
The dogs usually only take a few minutes to spot Covid-19, making the dog identification process much quicker and more cheaper than man-made testing. This type of testing is particularly appealing to poorer countries with limited lab testing facilities.
So what exactly are the dogs smelling?
It has been known for some time now that specific volatile organic compounds (VOCs) are associated with particular viral and bacterial infections. Dogs are better at identifying VOCs than humans in laboratories, and its suspected that the dogs are picking up a distinct configuration of VOCs that’s produced when the human body interacts with the SARS-CoV-2 virus.
Just how effective are covid-19 stiffer dogs?
A Dog’s nose contains around 300 million odour receptors, compared with the human endowment of around 5 million, that makes them able to detect the smallest concentrations of odour.
Dogs only need a few molecules, in some cases as little as ten molecules of SARS-CoV-2, to identify the virus, whereas standard testing requires around 20 million molecules, and clearly such testing won’t pick up cases in the early stage of development.
A recent study from Hanover University’s Veterinary Medicine School, using trained sniffer dogs presented with human saliva samples, has put the coronavirus detection rate at 94%, confirming the dog’s ability to pick the smallest concentrations of SARS-CoV-2 for both asymptomatic and symptomatic covid-19 cases.
Preliminary tests, carried out by researchers at the University of Helsinki, show that dogs detect the covid-19 virus with an almost 100 per cent certainty, by comparison conventional testing is a very rough determination of the presence of SARS-CoV-2.
So, we’ll be seeing sniffer dogs at airports soon?
Sadly, you won’t get a warm welcome from a tail-wagging dog. People taking these tests will wipe or swab their skin, and the sample is then placed in a container that is presented to the dog, usually in another area. Positive cases will then be referred to medical services.