Using a dog's nose for our own benefit

Dogs- we know they have amazing noses, but how amazing are they? The part of a dog’s brain that analyses smell is 40 times greater than that same part in human brains [1]. So, to answer the question; dogs noses are incredible. We use dog’s noses as biosensors for detection of all sorts of things; drugs, explosives, food, cancer, and as medical alert dogs in diabetes and epilepsy. But the recent pandemic has got us wondering- can we use them to detect COVID-19? I know I would prefer to be sniffed by a dog than a nose and throat swab-but can they do it? With a reliability rate of 85-90% in detecting diseases from odours and the ability to detect odours at dilutions of parts per trillion- the equivalent of one teaspoon of sugar in two Olympic sized swimming pools of water [2]- it’s safe to say dogs fit the bill for the job.

But, how would we train them? Well, one company- The London School of Hygiene and Tropical Medicine- has got an adorable team of six dogs (as shown below) who are being trained to help detect COVID-19- you can visit the link to find out more about these guys [3]. They are training these dogs by firstly collecting samples from COVID-19 infected and uninfected people and then using those odour samples with the six dogs for an intensive training programme to help teach them to correctly identify COVID-19, something they do naturally but are trained to do it on command for rewards [4]. If they are successful, they can work with other partner companies and scale up the operation to deploy these dogs throughout the pandemic for a non-invasive method of COVID-19 detection.

Photos of the Canine COVID-19 detection team at LSHTM

Now I know what you’re thinking, that sounds great but how reliable are they? Dogs have already been trained to detect lung cancer because they can detect changes in the patterns of gasses/chemicals emitted from a patient (called VOC’s), respiratory infections and COVID-19 cause changes in these patterns of gasses/chemicals too, so, therefore, we could assume dogs could detect these diseases too [2]. Research carried out with detection dogs in Finland and Lebanon have shown that the dogs can identify cases days before conventional tests pick up the virus, suggesting that these incredible dogs can spot infection before symptoms start [5]. Another researcher, Sarkis form Lebanon, carried out a similar test with 18 trained dogs who screened 1,680 people, 158 of whom had tested positive for COVID-19 confirmed by PCR tests [5]. The results; the dogs identified negative COVID-19 cases with 100% accuracy and positive COVID-19 cases with 92% accuracy- absolutely mind-blowing stuff [5]. But these results are also focussed on the reliability of the PCR tests, whereby 4% of these are said to be false positives in the UK and 2-33% are said to give false negatives [5]. To assess this, a German study trained the dogs by using mouth and windpipe samples from seven people hospitalised with COVID-19 and seven uninfected people, these results were less accurate but still highly accurate with the dogs identifying 83% of positive cases and 96% of negative ones [5].

Photo of a dog at LSHTM in training

Another research study also looked at dogs detecting COVID-19 from sweat and urine and the researcher says “they can do it”, however, this research is still under review and results are not final, but with 1,000 sweaty t-shirts from COVID-19 positive and negative humans being smelt [5]- I look forward to the results! The problem is with a lot of these studies is the sample size is too small to confidently state how good these dogs are, but these studies do show promise that dogs could be so useful in COVID-19 detection. One key benefit of these dogs is that one dog can screen 250 people in an hour in facilities such as airports or stadiums, they are also much cheaper to run than other current testing methods such as PCR (the COVID 24-hour tests) [4].

I do think we need to tap into this more; dogs are so incredible and so motivated to do stuff like this because they love smelling and pleasing humans- so let’s take advantage of that! Dogs are so amazing and loyal but also just highly skilled creature; we can use these skills for our benefit because they enjoy it! We’re not forcing them and I’m sure if they didn’t want to, we would know about it very quickly! Animals have so many skills that we are blind to because we think human knowledge is the best skill, but if we just looked around us these loyal companions could be utilised in so many incredible parts of our lives.