Sniffer dogs and coronavirus: Over the past couple of months, two separate studies have been conducted to test if sniffer dogs can detect the presence of coronavirus in humans, with both having reported that dogs had an accuracy of more than 90%. These studies are also not the first of this kind to be conducted during the pandemic. Considering that sniffer dogs are already trained for detection of other illnesses, explosives and drugs, it is not surprising that numerous researchers thought of testing if sniffer dogs would be accurately able to detect this infection as well.
However, now that some very positive data from two studies has surfaced, does this mean that the testing for coronavirus will now be done by sniffer dogs? According to a report in IE, the present evidence says that dogs could be used in crowds to identify people who are potentially infected with COVID-19, and while conventional testing would still be necessary, the presence of dogs would reduce the need for people to undergo them.
One of the studies was published in April in journal PLOS One by researchers at University of Pennsylvania. They said that eight trained Labrador Retrievers and one trained Belgian Malinois were able to identify patients who had tested positive for the virus based on their urine samples. While their accuracy in detecting positive cases was 96%, they were not able to identify false negatives with the same accuracy levels.
On the other hand, the second study was conducted by London School of Hygiene and Tropical Medicine (LSHTM) researchers, who released the pre-print of their study last week. It was a part of a six-year study that the government of the UK is funding. The researchers of this study stated that their fleet of six trained dogs had been able to identify odour samples of coronavirus positive people with an accuracy of 94%, while that of uninfected people with an accuracy of 92%.
Numerous studies have found that waste products from people who have tested positive for the virus – like urine, saliva and sweat – do have distinctive smells, as they contain some compounds which have different smells depending on whether the individual has been infected with coronavirus or not.
Considering the heightened sense of smell of dogs as compared to humans, the sniffer dogs are likely to pick up on this distinctive smell, much like how they do for other services as well. However, the UK study is not presenting sniffer dogs as an alternative to COVID-19 testing but rather as a complementary aspect. Giving an example of what they were proposing, the researchers said that at airports, sniffer dogs would first identify potentially infected passengers, after which only these passengers would need to undergo an RT-PCR test for confirmation. The study found that this approach helped in detection of nearly 91% of symptomatic and asymptomatic infections.
However, the ability of these trained dogs has yet to be tested in the real world as so far, the results are only based on trials conducted in a simulated environment.