Dogs are being trained to recognise the distinctive odour produced by those with particular illnesses, such as Covid-19. The scent is undetectable to the human nose, but dogs are known to have up to 100, 000 times the smelling ability of humans and can therefore correctly identify individuals with the virus. As of now, six dogs have been trained and are able to recognise different variants of the disease as well as distinguishing coronavirus from other respiratory illnesses.
How accurate is this test?
The method of using ‘sniffer dogs’ isn’t 100% accurate. When judging the accuracy of a test, it's important to consider the number of false positives and false negatives. A false positive is when a test shows a positive result, but the person does not actually have the disease. On the other hand, a false negative is when the test shows a negative result, but the patient actually has the disease. How do you think this will impact people who take the test? If a test produces lots of false positives or false negatives, do you think it is still worth doing?
What are the benefits of being screened for COVID-19 by dogs?
This method of screening can be employed at mass gatherings and airports to prevent the spread of disease, as individuals who may have the virus can be isolated and tested. As a result, society would be able to continue large events such as weddings, and even travel, without the current restrictions. How could this be implemented? Why might people not approve of this?
Are there other illnesses we could train dogs to detect?
Recent research has shown that some species of dogs can detect the scent of diseases including cancer, Parkinson’s and malaria. Whilst the dogs won't always be correct, this method may help identify patients who have the disease scent. They can then undergo the necessary tests and be formally diagnosed with the disease if they actually have it. This may lead to them receiving early treatment and stopping their disease from progressing. Can you think of any disadvantages to this? Do we really need this? What impact may false positives and negatives have on the patient and their family.
- Can you think of reasons someone may have a false positive or false negative test result?
- Imagine the sniffer dogs identified someone to have Covid-19. How would you convince this person to be formally tested in a Covid-19 test centre?
- If you're interested in learning more about the accuracy of different tests, have a read about the concepts of sensitivity and specificity here:
https://www.healthnewsreview.org/toolkit/tips-for-understanding-studies/understanding-medical-tests-sensitivity-specificity-and-positive-predictive-value/