Specially-trained dogs capable of sniffing out coronavirus infections in passengers have been deployed in airports around the world. Helsinki Airport is the latest to avail of their services, hiring four dogs this week — ET, Kössi, Miina and Valo — who have demonstrated their ability to sniff COVID-19 in people before they showed symptoms.

As airports ramp up their testing capabilities to help passengers travel safely, some have employed the help of sniffer dogs. This week, Helsinki Airport became the first in Europe to use deploy these dogs after a similar trial was launched in Dubai this summer.

COVID-19 sniffer dog at a press conference held at Helsinki Vantaa International Airport in Finland
ET poses for photos on his first day at work in the airport ©Xinhua News Agency/Getty Images

In Helsinki, the specially-trained dogs are capable of detecting the virus within 10 seconds and can identify its presence from a much smaller sample than the PCR tests used by health care professionals. According to researchers from the University of Helsinki, the whole process takes about one minute. Passengers are required to supply a sweat sample by dabbing their necks with a wipe. The wipe is then placed in a jar with a funnel-like opening to be studied by the dog at a safe distance, and is lined up alongside other jars containing different scents. Once the dog detects the virus, it will either yelp, paw or lay down. The passenger will then be taken for a nasal swab test to confirm.

Medical dog training.jpg
Dogs are trained to sniff samples in the laboratory in Milton Keynes © Medical Detection Dogs

According to the university, their dogs were able to detect the virus in humans with almost 100% accuracy in the preliminary trail, sometimes before the patient developed symptoms.

Four sniffer dogs, ET, Kössi, Miina and Valo, got their noses to work this week, working in shifts, with two on duty while the other two rest. In a statement, Anette Kare, of Finland’s Smell Detection Association, explained: “Dogs need to rest from time to time. If the scent is easy, it doesn’t wear out the dog too much. But if there are lots of new scents around, dogs do get tired easier.”

The coronavirus sniffer dogs named Valo (L) and E.T. stand by their trainers at the Helsinki airport in Vantaa,
Valo (L) and E.T. stand by their trainers © Aimo-Koivisto/Leh Lehtikuva/AFP/Getty Images

Additional experiments have been carried out across Europe in recent months to see if odour detection dogs can accurately identify COVID-19. The charity Medical Detection Dogs is working with the London School of Hygiene and Tropical Medicine to see whether their dogs – who are trained to detect malaria, cancer, Parkinson's and bacterial infections through the sense of smell – can be re-trained to provide a rapid, non-invasive diagnosis of the virus.

While in Germany researchers last month from the University of Veterinary Medicine Hanover trained army sniffer dogs to distinguish between samples of fluids taken from healthy patients and those infected with COVID-19. The dogs had an accurate detection rate of 94%, with 157 correct positive identifications, 792 correct reflections of non-infected samples and 33 incorrect results.

Their findings were published in the BMC Infectious Diseases journal with the team concluding that "in countries with limited access to diagnostic tests, detection dogs could then have the potential to be used for mass detection of infected people. Further work is necessary to better understand the potential and limitation of using scent dogs for the detection of viral respiratory diseases."

This article was first published on August 12 and updated on September 24, 2020.

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This article was first published August 2020 and updated September 2020

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