With their superior nose power, dogs have been trained to sniff out various diseases, including diabetes, malaria and tuberculosis. Now, new preliminary research led by the University of Veterinary Medicine, Hannover, suggests that pups could also detect when people are infected with the SARS-CoV-2 virus, which causes COVID-19.
Currently, in order to detect COVID-19, a swab taken from someone’s nose or throat is sent for testing. But this method can be time-consuming and costly, particularly in developing countries, which means that people are often only tested if they are showing symptoms.
In this study, it took one week to train eight sniffer dogs to detect the virus, by presenting them with saliva samples and swabs taken from COVID-19 patients, as well as healthy people with no history of the disease.
After training, the dogs were presented with 1,012 randomised samples, and they correctly identified 157 positive samples and 792 negative samples, for an overall detection rate of 94 per cent.
“We think that this works because the metabolic processes in the body of a diseased patient is completely changed,” said Prof Maren von Köckritz-Blickwede, who took part in the research. “And we think that the dogs are able to detect a specific smell of the metabolic changes that occur in those patients.”
According to Köckritz-Blickwede, the next step will be to establish whether the dogs can differentiate between COVID-19 and other diseases like influenza.
While more research needs to be carried out, this preliminary study shows that the use of sniffer dogs could offer a quick, accurate way to detect COVID-19.
The team have suggested that the technique could be particularly useful at airports, sports stadiums, mass gatherings and country borders, in order to help prevent outbreaks of coronavirus.
Reader Q&A: Why have big cats evolved but not big dogs?
Asked by: Jonny Thompson, Glasgow
Big cats mostly hunt alone and rely on a short burst of speed to catch their prey, and swipes from their claws to bring it down. Wild dogs hunt differently, using teamwork to chase prey over long distances until it collapses from exhaustion. A larger body is a liability in this sort of endurance contest – it requires more energy to haul around and doesn’t improve the chances of a kill.
We colloquially group cats and dogs together because we keep domestic versions of both of them as pets, but they are different animals that have evolved to fit different niches. Cats and dogs are both in the Carnivora order, but their last common ancestor lived about 42 million years ago.
Since then they have diverged into feliforms (cats, hyenas and mongooses) and caniforms – a more diverse group that includes raccoons and walruses, as well as dogs. Bears are caniforms too, and are more closely related to dogs than cats are. So you could argue that big dogs do exist, and the equivalent of the tiger in the dog world is a grizzly bear!