Dogs can be trained to detect Covid-19 by sniffing human sweat, study suggests

A trained dog takes part in a Covid-19 sniffing test.

(CNN)Dogs can be trained to detect Covid-19 by sniffing human sweat, according to a proof-of-concept study published on Thursday.

Detection dogs are already a common sight in airports and some other public places -- usually, they're sniffing out drugs, weapons or explosives.
But specially trained dogs have also been taught to detect infections and diseases, including colon cancer, malaria and Parkinson's disease.
    Now, many countries worldwide are exploring the possibility of using dogs as a rapid, reliable and relatively cheap way to prescreen people for Covid-19 or perform rapid checking in certain circumstances, like at airports.
      In the United Kingdom, a team from the London School of Hygiene and Tropical Medicine are training six dogs in the hope that they will be able to detect Covid-positive people -- even if they have no symptoms.
      In Finland, a group of sniffer dogs trained to detect Covid-19 began working at Helsinki Airport in September in an effort to identify those who have contracted the virus and in Chile police dogs are being trained to sniff out Covid-19 in humans.

      Scent detection of Covid-19

        In this new study, researchers based in France and Lebanon took sweat samples from the underarms of a total of 177 patients from four hospitals in Paris and one in Beirut -- 95 had tested positive for Covid-19, while 82 had tested negative. It was important that both the negative and positive samples came from the same hospitals so the dogs wouldn't be picking up on a particular "hospital odour," the researchers said.
        Using some of the sweat samples, they trained 14 dogs that had been working as explosive detection dogs, search and rescue dogs or colon cancer detection dogs to take part in the study. The scientists did not use dogs trained to detect illicit drugs because they could not rule out whether study patients who had provided sweat samples had used prohibited substances.
        Six dogs -- Guess, Maika, Gun, Oslo, Bella and Jacky -- had their sniffing abilities formally tested in the study. Five of them were Belgian Malinois, a common breed for French working dogs, and Jacky was a Jack Russell terrier.
        Shown here is one of the detection dogs that took part in the study.