Early studies using sniffer dogs to detect Covid-19 show some promise
Sniffer dogs at international airports at Saudi Arabia, Lebanon and Finland are being trained to sniff out the coronavirus disease from the sweat of arriving travellers with some reports saying that these canines have successfully smelled out Covid-19 before the individual’s RT-PCR or antigen test reports confirmed they had the infection.
According to the Nature science journal, groups working with dogs to detect Covid-19 in people met in an online workshop called International K9 team to discuss their findings. Several researchers have, however, warned that dogs cannot be used entirely to detect Covid-19 in people but initial findings show promising results. “No one is saying they can replace a PCR machine, but they could be very promising,” Holger Volk, a veterinary neurologist at the University of Veterinary Medicine Hannover in Germany told Nature.
Volk is leading an effort to train and study Covid-19 sniffing dogs but he did not speak at the event.
This is an ongoing study whose final report will be released in December as researchers are now analysing whether the dogs found coronavirus disease in travellers whose infection was later confirmed by a PCR test.
In Finland’s Helsinki airport, three dogs named Kossi, ET and Miina, sniffed swabs taken from 2,200 passengers throughout October and found the virus in 0.6 percent of travellers, according to the Agence France Presse. “We have done 16-17,000 PCR tests at the airport and less than one per cent are positive,” Finnish lawmaker Timo Aronkyto told AFP. “They are about the same, I don’t think there is a statistical difference,” Aronkyto said when asked about the results found out by the dogs.
Dogs in Finland and Lebanon have identified Covid-19 cases days before conventional tests picked up the virus, suggesting that they can spot infection before symptoms start, according to data presented at the K9 meeting.
Nature said Riad Sarkis, a surgeon and researcher at Saint Joseph University in Beirut who is a part of a French-Lebanese project that has trained 18 dogs, used the best two of them for the airport trial in Lebanon. The canines screened 1,680 passengers and found 158 Covid-19 cases that were confirmed by later lab tests. The animals correctly identified negative results with 100% accuracy, and correctly detected 92% of positive cases, according to unpublished results. “This is very accurate, feasible, cheap and reproducible,” Sarkis was quoted as saying by the journal.
Researchers have said that dogs may be able to identify illnesses by sniffing out volatile organic compounds or VOCs which human beings leave out when they are ill. As the molecules evaporate readily, dogs are often able to pick up the scent created by these VOCs.
Cynthia Otto, who heads the Penn Vet Working Dog Centre at the University of Pennsylvania in Philadelphia, said she has observed dogs can sniff out the difference between people infected with Covid-19 and those who have tested negative through their urine and sweat.
Experts highlighted that these studies conducted by researchers until now have taken samples from a few patients. Otto said the dogs could be smelling a specific scent of the samples rather than that of Covid-19. “The dogs can do it. The challenge is the ignorance that we have as humans as to what can confuse the dogs,” she said.
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