Now, according to German researchers, trained dogs can sniff out coronavirus infections.
A new study, which was piloted by the University of Veterinary Medicine Hannover, the Hannover Medical School and the German Armed Forces found that, if properly trained, dogs were able to discriminate between human saliva samples infected with SARS-CoV-2 and non-infected samples with a 94% success rate overall.
The hope is this method of detection could be one day be used in public areas such as airports, sporting events and other mass gatherings (in addition to laboratory testing) to help prevent future Covid-19 outbreaks, according to researchers.
To conduct the study, researchers trained eight dogs from Germany's Armed Forces for one week. The trained dogs sniffed the saliva of more than 1,000 people that were either healthy or infected with the virus. Samples infected with Covid-19 were distributed at random and neither the dog handlers nor the researchers on site knew which ones were positive.
In a YouTube video about the project, Maren von Koeckritz-Blickwede, a professor at the university, who conducted the study, says they think dogs are able to do this because the metabolic processes of an infected person "completely change."
"We think that the dogs are able to detect a specific smell of the metabolic changes that occur in those patients," she says.
While more research is still needed, Von Koeckritz-Blickwede says the next step is to train dogs to differentiate Covid-19 samples from other diseases like influenza.
According to the Centers for Disease Control and Prevention, while dogs can get infected with Covid-19, there is no evidence that animals play a significant role in spreading the virus.