In a bid to speed up COVID testing at airports and other public buildings, research has been carried out to see if dogs can be trained to detect people infected with Covid-19 by smell. Sniffer dogs have already been trained to detect the distinctive odours of diseases like cancer, malaria and Parkinson's, picking up scents that are far below the level at which humans can smell them.
Six dogs were given socks, face masks, T-shirts and other items that had been worn by COVID sufferers to accustom them to the smell. The dogs were given rewards when they correctly identified whether a test item belonged to someone with COVID or not. In the tests, dogs were found to pick up 88% of infections, including cases where the patient was asymptomatic, which is almost as good as PCR tests, which pick up 96% of cases. It is significantly better than lateral flow tests, which are around 72% accurate. They were also able to identify infections whichever variant was involved.
While dogs alone would not be able to confirm that a person was infected, they could be used as a first line of defence, as two dogs can screen 300 people in half an hour. Any people they give a positive result for could then be given a PCR test to confirm the diagnosis.
While these initial tests have been very successful, it will need further, more detailed laboratory work before dogs can be deployed to check people at mass gatherings.
BBC News, 24 May; Times, 2 June 2021.