How dogs' noses can help us in the fight against coronavirus
A blog by our dog welfare expert Dr Samantha Gaines.
We all know that dogs have a great sense of smell. It can help them locate their tennis ball in the long grass and means they're excellent at hoovering up even the tiniest of crumbs under the kitchen table. But their sense of smell - which is 10,000 to 100,000 times more sensitive than ours - has also been successfully harnessed by people to develop an extremely useful, life-saving role; sniffing out diseases.
And now, Covid dogs are being trialled as a potential approach for detecting coronavirus in people as the UK Government investigates ways to tackle the global pandemic. But, why is it that dogs are such great detectors?
Why dogs are so good at detecting things with their nose
Dogs live in a world of smell and have many features which give them truly amazing olfactory abilities. When it comes to sniffing, dogs are pretty specialised!
They take long sniffs when a smell is far away. The nostrils dilate and the alar fold (a structure just inside the nostril) opens to allow air to rush in.
Short sniffs are used for near smells. Dogs assess the concentration of the odour to find where it's strongest by scanning the surface and surveying the area which can result in as many as five to 12 sniffs per second!
There's a reason why dogs' noses are wet
Dogs' noses are soft and moist to capture the odour. They're specifically shaped and have highly developed muscles that maximise the amount of air that can be pulled in. They're designed so that during the exhale, air leaves via slits on the side which means that the amount of odour displaced is small and the concentration unaffected but this action also creates a 'puff' which lifts even more of the odour and 'suction' to get the next lot of air into the nose.
The nostrils can also be used separately and differentially. For example, when sniffing something new which is likeable or neutral they will start with their right nostril and then switch to their left.
A second nose
Dogs have what can be described as a second nose - the vomeronasal organ (VNO) which sits under the bone separating the nostrils and above the roof of the mouth. Odours must be dissolved into the tissue and sucked inside to reach this organ and if you ever see your dog grimacing and chattering their teeth or licking the ground then this is what he's trying to do.
This organ allows the dog to detect species-specific chemical signals - or pheromones - which wouldn't be detected using the normal olfactory route. These signals communicate information such as whether the animal is male or female, ready to mate, as well as their health.
When it comes to the neural processing of odours this is just as impressive as their physical processing. Odours travel to an area called the olfactory recess which is a labyrinth of thin bones covered in a tissue or epithelium housing receptor cells - these detect the odour.
The surface area of this tissue in dogs is between 150 and 170cm2, in humans, it's just 5-10cm2. Information about the odour is then processed in the olfactory bulb which is approximately 40 times larger in dogs than in us!
These features are why dogs can use their noses to detect a huge array of odours. And they can be trained to use their sense of smell to help people detect possible hazards as well as medical conditions or diseases.
We use dogs to detect a huge array of different odours including:
- illegal wildlife products
- and many more ways.
Are dogs able to help us detect coronavirus?
Just this week the UK Government has announced a £500,000 clinical trial to see if dogs can successfully detect coronavirus before symptoms appear. As dogs have been successfully trained to detect other viruses they may also be able to detect coronavirus. If this is the case, then dogs could be deployed to key points of entry into the UK to assist with the rapid screening of people travelling from abroad, providing a new early warning measure.
The research is being carried out in collaboration between the London School of Hygiene and Tropical Medicine, the charity Medical Detection Dogs and Durham University. The dogs - referred to as the 'Super Six' - include several rescue dogs and they'll soon start their training.
Dog wee is dog social media
It's without a doubt that the dog's sense of smell is astonishing and there are also lots of ways to unleash your dog's sniffing potential at home. You might want to hide your dog's food or a favourite toy so that he has to use his nose to find it. An even simpler way is to let him sniff when out and about. Marks on objects like lamp posts tell other dogs not only that they were there but information about themselves as individuals - much like the way we use social media!