“It’s not unlike people who have incredible intelligence, but often struggle in other ways,” says Guest of Asher’s transformation.The news that dogs such as Asher could be deployed to detect Covid-19 might have an “and finally…” ring to it. But there is serious science behind the idea. There has long been anecdotal evidence that many, perhaps all, diseases have a telltale odour. Yellow fever, for example, is said to smell like raw meat; tuberculosis starts out as wafts of stale beer, but later becomes more like soggy cardboard with notes of brine. These are just the ones that humans can notice – and compared to most animals, we have an abysmal sense of smell. Our olfactory epithelium, the area of the nasal cavity responsible for detecting odours, is 30% smaller than a canine’s. This leads to a staggering disparity: the ability of a dog to place an odour is estimated to be somewhere between 10,000 and 100,000 times better than that of the average human.
“If a dog comes up to something they like the odour of, they sniff really hard and rapidly, don’t they?” explains Guest. “You can hear that sniff-rate go up and they’re actually able to push air in and out of their nostrils at slightly different rates. This produces a little vortex that pulls up the volatiles that much more quickly. They’ve also got an ability to push old air out of the slits of their nose, the sides, and pull new air in at the same time. This information goes to two different parts of the brain and these two bits talk. Then they recognise the odour.”For a dog who loves to tear apart stuffed animals, make a durable activity ball with a Hol-ee rubber ball, scraps of fabric, and treats.
The pair put together a pitch for a UK government grant to investigate further. Bio-detection dogs are already a familiar sight at international ports of entry and border crossings where they are used to find drugs, explosives and other contraband. Each dog can screen up to 250 people per hour. “Essentially what you’re doing is you’re diverting their attention from drugs and explosives to a disease,” explains Logan.
In May, Logan’s team at the London School of Hygiene and Tropical Medicine, in collaboration with Medical Detection Dogs and Durham University, was awarded £500,000 of government funding. The hope is that dogs will be able to assist with early identification of Covid-19 and reduce the need for quarantine for travellers arriving to the UK. Guest is clearly confident: “So far there’s never been a disease we can’t find.”Play a Nice Interactive Game of Tug With Your Dog. A 5 minute game of tug works wonders for tiring out your dog & letting him get rid of some of that pent up energy. (and no – it won’t make your dog aggressive despite the old myth)
It is not hardto imagine that there might be some scepticism about the project. “I know some people think it’s a wacky idea,” says Guest. “When it was discovered that dogs could smell some of these diseases, you immediately got people saying, ‘OK, that’s fine but how are you going to roll a dog out to every doctor’s surgery?’ But that was really never where this was ultimately going to go.”
A behavioural psychologist by training, Guest spent many years working with hearing dogs for the deaf. Over time, she kept coming across reports of dogs who had alerted their owners to serious illnesses. “I had a colleague whose dog warned her about a melanoma on her calf when she was in her early 20s,” she recalls. “From her description, I knew this dog had smelt it, but I had no idea how I’d manage to ever prove this.”
The research became personal for Guest, too. She started Medical Detection Dogs in 2008, and a year later, she noticed that her own dog, a fox-red labrador called Daisy, was acting strangely around her. Normally placid, she kept jumping up at Guest, pawing at her chest. Guest checked and felt a lump. “It was very, very deep-seated under that lump, but I had breast cancer; I was 45,” she recalls. “My consultants both said that had Daisy not warned me, my prognosis would have been very different. I wouldn’t have had a mammogram for another five years probably.” Medical Detection Dogs currently has around 100 dogs assisting people one-to-one with a range of illnesses, including type 1 diabetes and postural orthostatic tachycardia syndrome (PoTS). They are trained to alert their owners to tiny odour changes, which might be a precursor to an emergency. The charity also has a smaller division of bio-detection dogs, who are trained to find neurological diseases, such as Parkinson’s, as well as cancer and malaria.The Covid-19 project is currently in the phase of sample collection. Sterilised socks and stockings made from nylon, which clings to body odours especially well, and face masks have been sent out to around 3,200 NHS staff, who will wear them for a standardised amount of time before returning them to Logan’s lab for analysis. Crucially, all the NHS workers taking part in the trial will be asymptomatic. “We’ll end up with a very high number of samples from people who are uninfected, and a smaller group of samples from people who are infected,” says Logan. “And that’s fine. Because, actually, we need a lot of controls. We need a lot of background noise for the dogs to ignore.”
Once Logan’s samples have been processed, they will be cut up into small pieces: some will be sent for further analysis, the rest will go to the dogs and their handlers, initially labelled but ultimately double-blind. If Covid-19 does have a distinctive smell and the dogs can detect it, the trial will then move to practical outreach. Logan imagines they will work with an airport, probably Heathrow, and travel hubs, such as train stations, that have a heavy footfall of commuters.“If you’ve got a plane with 500 people coming off, 10% may be asymptomatic or pre-symptomatic,” says Guest. “The dog can quickly say, ‘Bang, bang, bang. You, you, you.’ It’s a 0.5 second sniff. The dog won’t make the final decision. The person will have a test. But at the moment there’s no other way of rapidly screening people like that – especially asymptomatics.”On a hot summer day, fill up an inflatable pool with water and ice.
For Logan, who hopes to have initial results from the project in August or September, the dogs could be “a quick win” while the search for a Covid-19 vaccine continues elsewhere. “Any strategy that puts all your eggs into one basket is not a good strategy,” he says.
Logan is especially encouraged that he has already had messages from people convinced the virus does have a distinct odour. He says, “We’ve had a lot of people contact us, particularly medical workers, people that are in care homes, and people in hospitals who are saying, ‘We can smell it. I can walk into a room and I can tell there are patients in here with Covid-19.’ We’ve got to take that with a pinch of salt, because that’s not scientific proof, but it gives us further hope that it does exist.”
In the future, it is likely that a device, perhaps even our smartphone, will tell us we are ill before we have any idea ourselves. Medical Detection Dogs is currently partnering with Dr Andreas Mershin, a quantum physicist at the MIT Center for Bits and Atoms, in Massachusetts, on using dogs to teach artificial-intelligence technology how to recognise the smell of prostate cancer. Logan is also convinced that we will make increasing use of sensors, maybe one that’s worn on your skin or a device you blow into, similar to a breathalyser.
For now, though, our best hope might be dozing on Guest’s floor, after a hard morning sniffing for tennis balls. In fact, Asher won’t be deployed in Covid-19 searches, because of his previous experience with malaria, it couldn’t be guaranteed which disease he was stopping for. His main contribution will be in confirming that Covid-19 does have its own smell. “Because Asher has more experience, he’ll be able to tell me, ‘There’s definitely a difference here. Let’s crack on,’” says Guest. “He won’t go to the final phase, he’ll peel off and a young girl will come in.”
This softens the kibble and makes the food much easier to chew.
Guest looks over at Asher fondly and whispers, “But we haven’t told him that yet…”