Medical alert dogs can detect odours as dilute as a TEASPOON of sugar in two Olympic-sized swimming pools
- The charity Medical Detection Dogs claims the animals are better than sensors
- It says they are our ‘best defence’ in early diagnosis of serious illnesses
- Dogs are believed to be able to smell cancer, Parkinson’s, diabetes and malaria
- They do it by picking up on volatile organic compounds in our skin and breath
Dogs’ sense of smell is so strong a charity claims they are the ‘best defence’ in diagnosing serious illnesses early.
A scientific study found the animals’ noses can be so good they could detect a teaspoon of sugar in five million litres of water – two Olympic swimming pools.
And, hitting 96 per accuracy in some tests, experts say dogs can be more accurate than electronic sensors at recognising the smell of molecules released by certain diseases.
Cancer, diabetes, Parkinson’s disease and malaria are among the conditions dogs are said to be able to sniff out, and there could be potential for even more.
Dogs have such a strong sense of smell they could sniff out a teaspoon of sugar in the amount of water contained in two 50m swimming pools, according to researchers (stock image)
Research published in the scientific journal, Frontiers, found dogs’ sense of smell was so refined it could be measured in parts per trillion.
Medical Detection Dogs, the charity which did the research, said the animals have the potential to save lives.
It said the dogs could identify smells associated with human illness with between 81 and 96 per cent accuracy.
There have in the past been extraordinary tales of dog owners claiming their pets sniffed out their cancer.
And scientists at the University of Bristol last week revealed trained dogs could tell when diabetic people had dangerously low blood sugar with 83 per cent accuracy.
Dogs’ ability to sniff out sickness is believed to be down to their ability to smell molecules released into someone’s breath, skin or sweat when they are unwell.
These are called volatile organic compounds and dogs may signal they can smell something by paying an unusual amount of attention to their owner.
‘The dog’s ability to detect odours down to parts per trillion is the equivalent to detecting a teaspoon in the volume of water contained in two Olympic size swimming pools,’ said Dr Claire Guest, chief executive of Medical Detection Dogs.
‘The relevance of this study cannot be clearer: we can and should rely on medical detection dogs to help diagnose disease through associated volatiles at an early stage.
‘Our dogs have already shown the ability to detect cancer, diabetes, Parkinson’s disease and malaria.
‘This has the potential to save thousands of lives. The dog is a highly sophisticated bio-sensor with a fluffy coat and waggy tail.’
The study was believed to be the first in at least a decade to estimate the limits to dogs’ sense of smell – the olfactory detection threshold – in this way.
It involved 10 detection dogs from Medical Detection Dogs – four females and six males, ranging in age from two to 11.
There were three Labrador Retrievers, three Working Cocker Spaniels, two English Springer Spaniels and two Border Collies.
Dogs were asked to single out a target odour among a group of control samples.
All samples were presented to the dogs in a carousel with eight arms and the dogs sniffed each one. If they identified it correctly, they were given a food reward.
HOW DO DOGS ‘SNIFF OUT CANCER’?
Dogs have an extremely sensitive sense of smell and can pick up on ‘volatile organic compounds’, which are released from the early stages of many cancers, including ovarian, lung and colorectal.
Scientific studies have shown pooches can separate between blood and tissue samples donated from ovarian cancer patients and healthy people by picking up on minute quantities of VOCs.
Studies have also shown dogs can sniff out prostate cancer in a man’s urine, as well as breast and lung forms of the disease from compounds in a patient’s breath.
If a dog detects this on their owner, they may try to alert them by paying them more attention, sniffing them, or ‘comforting’ them by gently licking their hands or feet, or laying beside them for no reason.
If a person notices their dog is regularly acting differently around them, it may be worth looking out for other cancer symptoms, such as pain, fatigue and weight loss.
Experts have said specially-trained dogs could particularly help women with ovarian cancer, which has no screening programme and is usually only diagnosed when advanced.