Detecting COVID-19, the disease caused by Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) is not an easy task, despite the number of different testing regimes that exist. Right now, there are two types of COVID-19 tests: viral tests and antibody tests. The accuracy of both these tests is a big question for scientists and for governments. This is down to two factors- sensitivity and specificity.
To make matters worse, Research by Daniel Oran and Eric Topol of Scripps Research Institute estimated that around 40- 45% of all cases are asymptomatic i.e. people infected with the disease show no symptoms at all. Their research also found that such cases can transmit the virus even after the standard 14 day incubation period. The researchers said: “Because of the high risk for silent spread by asymptomatic persons, it is imperative that testing programs include those without symptoms.”
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Right now, that is proving to be a bigger challenge than expected. Shortage of testing kits and pushback against mask-wearing and social distancing measures from some groups have forced policymakers to find new ways to halt the spread of COVID-19. Which is why there is a greater push for the ‘test and trace’ system. By sheer coincidence, a charity may have found a new weapon in the fight against COVID-19: dog’s heightened sense of smell.
The idea is the brainchild of Dr Claire Guest, who runs the charity Medical Detection Dogs (MDD). MDD has been training dogs to use their incredible sense of smell to sniff out diseases, to help with early diagnosis. Dr Guest has been training dogs to detect diseases like malaria, when she decided to task Asher, a brown cocker spaniel, to try and smell COVID-19.
The Science of Dog’s Smell
MDD trains dogs to detect biological diseases like cancer, malaria and neurological diseases from urine and swabs. The charity was set up by Dr. Guest in 2008 after a dog detected melanoma in her colleague. Just like police dogs, these bio-detection dogs are able to identify any changes to a person’s odour, because scientists have managed to find evidence that all diseases have a telltale smell.
Human’s 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 we can detect a spoonful of sugar in a cup of tea, dogs have the ability to detect that same quantity in two olympic sized swimming pools.
Dr Guest explained how dogs are able to utilise this superior sense of smell. Talking to The Guardian, she said: “If a dog comes up to something… 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. This information goes to two different parts of the brain and these two bits talk. Then they recognise the odour.”
Professor James Logan, head of the department of disease control at the London School of Hygiene and Tropical Medicine has been working with MDD for two years on bio-detection. He was one of the first to show that malaria causes a change in body odour, which are too minute for humans to smell. Professor Logan found that mosquitoes, however, have the ability to identify that change, which they find attractive. This causes the transmission of malaria to speed up considerably.
A 2019 World Health Organisation (WHO) report found that “In 2018, nearly half of the world’s population was at risk of malaria.” Fighting the disease is proving to be a big challenge partially because studies have repeatedly shown that there is a high number of asymptomatic cases.
Logan and Dr Guest were in the middle of rolling out an MDD programme to detect malaria when the COVID-19 pandemic hit, which presented them with an opportunity to put that theory into practice for a more pressing issue.
We know that infections cause changes in body odour, that’s scientifically proven now,” Logan said. “And we know that dogs can detect odours and learn the smell of odours very effectively. That is also scientifically proven and well-known. So to me, it was a no-brainer.” The duo created a pitch for a UK government grant to investigate further. They wanted to divert bio-detection dogs already in place at border crossings and airports from sniffing for drugs and explosives to COVID-19.
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In May, the government awarded a £500,000 grant to Logan’s team at the London School of Hygiene and Tropical Medicine, in collaboration with Medical Detection Dogs and Durham University. MDD is currently in the first stage of training, having selected six dogs for the task – Norman (Working Cocker Spaniel), Digby (Labradoodle), Storm (Labrador x Golden Retriever), Star (Labrador), Jasper (Working Cocker Spaniel) and Asher (Working Cocker Spaniel) – who should be able to detect the disease within six to eight weeks as per MDD. Once trained, the dogs should be able to detect COVID-19 even in asymptomatic people, so that they can get tested.
Currently, Logan’s team is busy collecting samples for the dogs to train with, and to ensure that neither the dogs nor the handlers get infected, the team is collecting dead virus samples from previously asymptomatic NHS workers. The team hopes to end up with samples from both infected and uninfected workers so that they can train the dogs to identify the difference.
If all goes well and the dogs are able to identify COVID-19, the team hopes to move to practical trials at major travel hubs. “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.”
The team hopes to have initial results by August or September, potentially giving the UK a leg up in the battle against COVID-19. Right now, lab tests alongside contact tracing are the key method governments are banking on to curb the pandemic, but Logan believes that “any strategy that puts all your eggs into one basket is not a good strategy.” Bio-detection dogs may not end COVID-19, but they can certainly help in controlling the spread while allowing international travel to resume. Resuming travel is critical to the recovery of the economy, as the industry is responsible for 319 million jobs and contributed $8.8 trillion to the global economy in 2018 as per Traveldailynews.com.
Our best hope of resuming commercial air travel is probably snoozing on the floor of the facility in Milton Keynes, after a hard day of sniffing tennis balls.
Asher, one of the original dogs probably won’t be deployed, since he is already trained to detect malaria, and won’t be able to accurately differentiate between malaria and Covid, but his help will prove to be invaluable in the pandemic. So you should probably get ready (and excited) to see more dogs deployed at travel hubs in the near future if the trials go as expected.
If you wish to make a donation towards the study, you can do so through the team’s Indiegogo page.
Sources: Guardian, Medical Detection Dogs, Medical News Today, BBC
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