Figure 1: A line of samples–bodily fluids with only one of them infected–is presented in front of a dog training to detect coronavirus. Dogs are able to smell a certain odor from people who have different diseases. When the dogs correctly indicate a positive sample by pawing or nosing at it, they are given a treat.
Source Credit: Fodor’s Travel (LINK)
As we approach nearly a year and a half since the start of the global pandemic, many people are finally beginning to travel. However, people still need to go through the arduous process of taking safety precautions while boarding and disembarking a plane. Many airports require the passengers to wear masks and test for the virus before boarding. Not only is this procedure tiring and time-consuming for the passengers, but it is also costly for some. Testing once costs around $90 in many airports. Imagine how much that would be for a family of four on a round-trip. Fortunately, some scientists have succeeded in discovering a new method that may increase the efficiency of this process: specially trained dogs to sniff out people with the coronavirus.
Dogs often play a role in sniffing out weapons, drugs, or other diseases such as lung cancer thanks to their keen sense of smell. Compared to humans, who only have about 5 or 6 million scent receptors in their noses, dogs have about 300 million scent receptors, making them far superior to humans in smell. Although there is still ongoing research, scientists believe that human bodies release certain volatile organic compounds in gas form when sick. Despite the fact that they are undetectable to humans, dogs are able to sense the compounds. Depending on the disease, the smell also varies, so when trained properly, dogs are able to sniff people with specific illnesses.
During the training process, sweat, saliva, and other bodily fluids are found to be very useful. Similar to how they are trained to sit or fetch, dogs are given treats when they choose the correct sample of a certain disease. They indicate to the researchers the sample they have chosen by sitting next to it, pressing their nose against it, or even pawing at it.
One of the first studies in training dogs on how to sniff out the coronavirus involved sweat samples from 177 possible COVID-19 patients in Paris and Beirut; 14 dogs were trained with the samples. Of the 14 dogs, only six were selected–five Belgian Malinois and one Jack Russel terrier–to detect a positive sample. After dozens of trials with the randomly placed positive sample, the success rate varied between 76% and 100%. The two dogs that were previously trained to detect colon cancer had a 100% success rate out of 68 tests.
There was also a surprising result from this experiment. During the experiment, the dogs repeatedly marked two negative samples, and when the hospitals were notified of this, they found out that the tested individuals were actually positive. That is, the dogs were actually able to discover a false negative test.
However, there were also some cases of error. According to BBC, while the dogs were able to sense 88% of coronavirus cases correctly, they also incorrectly flagged 16% of them. Due to this possibility of error, researchers do not recommend depending solely on dogs to find people with the coronavirus. Until scientists succeed in training dogs to detect the virus with 100% accuracy or a more effective method emerges, airports would need to continue with the PCR tests. Fortunately, an increasing number of people are getting vaccinated. Although currently, even vaccinated travelers need to submit a negative COVID-19 test result, there is hope that testings would no longer be necessary in the future. Scientists hope that dogs would only need to be employed as a safety precaution.
Q&A Section
Sally: Since carrying these dogs for the virus detection is not entirely reliable, what kind of other methods or research are scientists planning to do to increase the accuracy? Are there other training methods?
The current method that most airports are undergoing is coronavirus testing. Although highly trained dogs have a higher accuracy rate, in the end, covid tests are more precise and easy to access (since it takes a lot of time and money to train them and there are very few dogs that are accurate). Unfortunately, there’s no other training method. In the majority of cases, dogs are trained with award systems where they would earn treats if they correctly identify a covid patient.
Xavier: Do you personally think further research should be done to increase the accuracy of the tests, or should the idea be scrapped entirely?
I personally think further research should be done because in the future when most people are vaccinated and the global pandemic ends (hopefully), airports won’t require people to take the covid tests anymore. However, even after the pandemic ends, there will still be a few people infected by the virus. In that case, I think the trained dogs can go around the airport and identify anyone who is infected by the virus.
Wooseok: Are there specific types/breeds of dogs that are more suitable for the purpose of covid-sniffing? If so, what are they?
The most common types of breeds that are trained to sniff out not just coronavirus but also drugs and other illnesses are German Shepherds, Belgian Malinois, Labrador Retrievers, and Border Collies.
John: How does COVID-19 affect the types of volatile organic compounds emitted from the human body?
Although exactly how the volatile organic compounds differ for COVID-19 patients is not known in full detail, studies have shown that they had higher levels of ethyl butanoate. In comparison with other respiratory diseases, covid patients have shown lower levels of butyraldehyde and isopropanol.
Works Cited
Editorial Staff | February 16, 2021 Topics: Research COVID-19. “Can Dogs Sniff Out COVID-19?” American Lung Association, www.lung.org/blog/can-dogs-detect-covid-19.
Schraer, Rachel. “Covid: Sniffer Dogs Could Bolster Screening at Airports.” BBC News, BBC, 23 May 2021, www.bbc.com/news/health-57200863.
Kramer, Jillian. “These Sniffer Dogs Are Learning to Smell the Coronavirus.” Animals, National Geographic, 19 May 2021, www.nationalgeographic.com/animals/article/see-dogs-trained-to-sniff-covid.
“Detection of Covid-19 by Volatile Organic Compounds in Exhaled Breath - Full Text View.” Detection of Covid-19 by Volatile Organic Compounds in Exhaled Breath - Full Text View - ClinicalTrials.gov, https://clinicaltrials.gov/ct2/show/NCT04714333.
Silk, Robert. “Planning to Get an Airport Covid Test? It Can Cost You.” Travel Weekly, Travel Weekly, 5 May 2021, www.travelweekly.com/Travel-News/Airline-News/Airline-group-sounds-an-alarm-over-prices-of-airport-Covid-tests.
“Which Dog Breeds Work Best for Drug Detection.” 3DK9 LLC, www.3dk9detection.com/news/what-breeds-make-the-best-drug-dogs.
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