The Nose Knows: Dogs Are Being Trained to Detect the Coronavirus
Security workers walk with detection dogs in an airport terminal.
Asher is eccentric and inquisitive. He loves an audience, likes keeping busy, and howls to be let through doors. He is a six-year-old working Cocker Spaniel, who, with five other furry colleagues, has now been trained to sniff body odor samples from humans to detect COVID-19 infections.
As the Delta variant and other new versions of the SARS-CoV-2 virus emerge, public health agencies are once again recommending masking while employers contemplate mandatory vaccination. While PCR tests remain the "gold standard" of COVID-19 tests, they can take hours to flag infections. To accelerate the process, scientists are turning to a new testing tool: sniffer dogs.
At the London School of Hygiene and Tropical Medicine (LSHTM), researchers deployed Asher and five other trained dogs to test sock samples from 200 asymptomatic, infected individuals and 200 healthy individuals. In May, they published the findings of the yearlong study in a preprint, concluding that dogs could identify COVID-19 infections with a high degree of accuracy – they could correctly identify a COVID-positive sample up to 94% of the time and a negative sample up to 92% of the time. The paper has yet to be peer-reviewed.
"Dogs can screen lots of people very quickly – 300 people per dog per hour. This means they could be used in places like airports or public venues like stadiums and maybe even workplaces," says James Logan, who heads the Department of Disease Control at LSHTM, adding that canines can also detect variants of SARS-CoV-2. "We included samples from two variants and the dogs could still detect them."
Detection dogs have been one of the most reliable biosensors for identifying the odor of human disease. According to Gemma Butlin, a spokesperson of Medical Detection Dogs, the UK-based charity that trained canines for the LSHTM study, the olfactory capabilities of dogs have been deployed to detect malaria, Parkinson's disease, different types of cancers, as well as pseudomonas, a type of bacteria known to cause infections in blood, lungs, eyes, and other parts of the human body.
COVID-19 has a distinctive smell — a result of chemicals known as volatile organic compounds released by infected body cells, which give off an odor "fingerprint."
"It's estimated that the percentage of a dog's brain devoted to analyzing odors is 40 times larger than that of a human," says Butlin. "Humans have around 5 million scent receptors dedicated to smell. Dogs have 350 million and can detect odors at parts per trillion. To put this into context, a dog can detect a teaspoon of sugar in a million gallons of water: two Olympic-sized pools full."
According to LSHTM scientists, COVID-19 has a distinctive smell — a result of chemicals known as volatile organic compounds released by infected body cells, which give off an odor "fingerprint." Other studies, too, have revealed that the SARS-CoV-2 virus has a distinct olfactory signature, detectable in the urine, saliva, and sweat of infected individuals. Humans can't smell the disease in these fluids, but dogs can.
"Our research shows that the smell associated with COVID-19 is at least partly due to small and volatile chemicals that are produced by the virus growing in the body or the immune response to the virus or both," said Steve Lindsay, a public health entomologist at Durham University, whose team collaborated with LSHTM for the study. He added, "There is also a further possibility that dogs can actually smell the virus, which is incredible given how small viruses are."
In April this year, researchers from the University of Pennsylvania and collaborators published a similar study in the scientific journal PLOS One, revealing that detection dogs could successfully discriminate between urine samples of infected and uninfected individuals. The accuracy rate of canines in this study was 96%. Similarly, last December, French scientists found that dogs were 76-100% effective at identifying individuals with COVID-19 when presented with sweat samples.
Grandjean Dominique, a professor at France's National Veterinary School of Alfort, who led the French study, said that the researchers used two types of dogs — search and rescue dogs, as they can sniff sweat, and explosive detection dogs, because they're often used at airports to find bomb ingredients. Dogs may very well be as good as PCR tests, said Dominique, but the goal, he added, is not to replace these tests with canines.
In France, the government gave the green light to train hundreds of disease detection dogs and deploy them in airports. "They will act as mass pre-test, and only people who are positive will undergo a PCR test to check their level of infection and the kind of variant," says Dominique. He thinks the dogs will be able to decrease the amount of PCR testing and potentially save money.
Since the accuracy rate for bio-detection dogs is fairly high, scientists think they could prove to be a quick diagnosis and mass screening tool, especially at ports, airports, train stations, stadiums, and public gatherings. Countries like Finland, Thailand, UAE, Italy, Chile, India, Australia, Pakistan, Saudi Arabia, Switzerland, and Mexico are already training and deploying canines for COVID-19 detection. The dogs are trained to sniff the area around a person, and if they find the odor of COVID-19 they will sit or stand back from an individual as a signal that they've identified an infection.
While bio-detection dogs seem promising for cheap, large-volume screening, many of the studies that have been performed to date have been small and in controlled environments. The big question is whether this approach work on people in crowded airports, not just samples of shirts and socks in a lab.
"The next step is 'real world' testing where they [canines] are placed in airports to screen people and see how they perform," says Anna Durbin, professor of international health at the John Hopkins Bloomberg School of Public Health. "Testing in real airports with lots of passengers and competing scents will need to be done."
According to Butlin of Medical Detection Dogs, scalability could be a challenge. However, scientists don't intend to have a dog in every waiting room, detecting COVID-19 or other diseases, she said.
"Dogs are the most reliable bio sensors on the planet and they have proven time and time again that they can detect diseases as accurately, if not more so, than current technological diagnostics," said Butlin. "We are learning from them all the time and what their noses know will one day enable the creation an 'E-nose' that does the same job – imagine a day when your mobile phone can tell you that you are unwell."
Podcast: The Friday Five weekly roundup in health research
Scientists have designed a phone app that could alert consumers to high levels of cancer-causing chemicals, Yale researchers revive organs in dead pigs, and more in this week's Friday Five.
The Friday Five covers five stories in health research that you may have missed this week. There are plenty of controversies and troubling ethical issues in science – and we get into many of them in our online magazine – but this news roundup focuses on scientific creativity and progress to give you a therapeutic dose of inspiration headed into the weekend.
Listen to the Episode
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Covered in this week's Friday Five:
- A new blood test for cancer
- Patches of bacteria can use your sweat to power electronic devices
- Researchers revive organs of dead pigs
- Phone apps detects cancer-causing chemicals in foods
- Stem cells generate "synthetic placentas" in mice
Plus, an honorable mention for early research involving vitamin K and Alzheimer's
The limits of digital privacy are becoming clearer in the post-Dobbs era, as a wide range of data sources can reveal online and offline activities, including whether a woman seeks an abortion.
Since the recent reversal of Roe v. Wade — the landmark decision establishing a constitutional right to abortion — the vulnerabilities of reproductive health data and various other information stored on digital devices or shared through the Web have risen to the forefront.
Menstrual period tracking apps are an example of how technologies that collect information from users could be weaponized against abortions seekers. The apps, which help tens of millions of users in the U.S. predict when they’re ovulating, may provide evidence that leads to criminal prosecution in states with abortion bans, says Anton T. Dahbura, executive director of the Johns Hopkins University Information Security Institute. In states where abortion is outlawed, “it’s probably best to not use a period tracker,” he says.
Following the Dobbs v. Jackson ruling in late June that overturned Roe, even women who suffered a miscarriage could be suspected of having an abortion in some cases. While using these apps in anonymous mode may appear more secure, “data is notoriously difficult to perfectly anonymize,” Dahbura says. “Whether the data are stored on the user’s device or in the cloud, there are ways to connect that data to the user.”
Completely concealing one’s tracks in cyberspace poses enormous challenges. Digital forensics can take advantage of technology such as GPS apps, security cameras, license plate trackers, credit card transactions and bank records to reconstruct a person’s activities,” Dahbura says. “Abortion service providers are also in a world of risk for similar reasons.”
Practicing “good cyber hygiene” is essential. That’s particularly true in states where private citizens may be rewarded for reporting on women they suspect of having an abortion, such as Texas, which passed a so-called bounty hunter law last fall. To help guard against hacking, Dahbura suggests using strong passwords and two-factor authentication when possible while remaining on alert for phishing scams on email or texts.
Another option for safeguarding privacy is to avoid such apps entirely, but that choice will depend on an individual’s analysis of the risks and benefits, says Leah Fowler, research assistant professor at the University of Houston Law Center, Health Law & Policy Institute.
“These apps are popular because people find them helpful and convenient, so I hesitate to tell anyone to get rid of something they like without more concrete evidence of its nefarious uses,” she says. “I also hate the idea that asking anyone capable of becoming pregnant to opt out of all or part of the digital economy could ever be a viable solution. That’s an enormous policy failure. We have to do better than that.”
The potential universe of abortion-relevant data can include information from a variety of fitness and other biometric trackers, text and social media chat records, call details, purchase histories and medical insurance records.
Instead, Fowler recommends that concerned consumers read the terms of service and privacy policies of the apps they’re using. If some of the terms are unclear, she suggests emailing customer service with questions until the answers are satisfactory. It’s also wise for consumers to research products that meet their specific needs and find out whether other women have raised concerns about specific apps. Users interested in more privacy may want to switch to an app that stores data locally, meaning the data stays on your device, or does not use third-party tracking, so the app-maker is the only company with access to it, she says.
Period tracking apps can be useful for those on fertility journeys, making it easier to store information digitally than on paper charts. But users may want to factor in whether they live in a state with an anti-abortion stance and run the risk of legal issues due to a potential data breach, says Carmel Shachar, executive director of the Petrie-Flom Center for Health Law Policy, Biotechnology, and Bioethics at Harvard Law School.
Consumers’ risks extend beyond period tracking apps in the post-Roe v. Wade era. “Anything that creates digital breadcrumbs to your reproductive choices and conduct could raise concerns — for example, googling ‘abortion providers near me’ or texting your best friend that you are pregnant but do not want to be,” Shachar says. Women also could incriminate themselves by bringing their phones, which may record geolocation data, to the clinic with them.
The potential universe of abortion-relevant data can include information from a variety of fitness and other biometric trackers, text and social media chat records, call details, purchase histories and medical insurance records, says Rebecca Wexler, faculty co-director of the Berkeley Center for Law & Technology. “These data sources can reveal a pregnant person’s decision to seek or obtain an abortion, as well as reveal a healthcare provider’s provision of abortion services and anyone else’s provision of abortion assistance,” she says.
In some situations, people or companies could inadvertently expose themselves to risk after posting on social media with offers of places for abortion seekers to stay after traveling from states with bans. They could be liable for aiding and abetting abortion. At this point, it’s unclear whether states that ban abortion will try to prosecute residents who seek abortions in other states without bans.
Another possibility is that a woman seeking an abortion will be prosecuted based not only on her phone’s data, but also on the data that law enforcement finds on someone else’s device or a shared computer. As a result, “people in one household may find themselves at odds with each other,” says K Royal, faculty fellow at the Center for Law, Science, and Innovation at Arizona State University’s Sandra Day O'Connor College of Law. “This is a very delicate situation.”
Individuals and corporate executives should research their options before leaving a digital footprint. “Guard your privacy carefully, whether you are seeking help or you are seeking to help someone,” Royal says. While she has come across recommendations from other experts who suggest carrying a second phone that is harder to link a person’s identity for certain online activities, “it’s not practical on a general basis.”
The privacy of this health data isn’t fully protected by the law because period trackers, texting services and other apps are not healthcare providers — and as a result, there’s no prohibition on sharing the information with a third party under the Health Insurance Portability and Accountability Act of 1996, says Florencia Marotta-Wurgler, a professor who specializes in online consumer contracts and data privacy at the NYU School of Law.
“So, as long as there is valid consent, then it’s fair game unless you say that it violates the reasonable expectations of consumers,” she says. “But this is pretty unchartered territory at the moment.”
As states implement laws granting anyone the power to report suspected or known pregnancies to law enforcement, anti-choice activists are purchasing reproductive health data from companies that make period apps, says Rebecca Herold, chief executive officer of Privacy & Security Brainiacs in Des Moines, Iowa, and a member of the Emerging Trends Working Group at ISACA, an association focused on information technology governance. They could also buy data on search histories and make it available in places like Texas for “bounty hunters” to find out which women have searched for information about abortions.
Some groups are creating their own apps described as providing general medical information on subjects such as pregnancy health. But they are “ultimately intended to ‘catch’ women” — to identify those who are probably pregnant and dissuade them from having an abortion, to launch harassment campaigns against them, or to report them to law enforcement, anti-choice groups and others in states where such prenatal medical care procedures are now restricted or prohibited, Herold says.
In addition to privacy concerns, the reversal of Roe v. Wade raises censorship issues. Facebook and Instagram have started to remove or flag content, particularly as it relates to providing the abortion pill, says Michael Kleinman, director of the Silicon Valley Initiative at Amnesty International USA, a global organization that promotes human rights.
Facebook and Instagram have rules that forbid private citizens from buying, selling or giving away pharmaceuticals, including the abortion pill, according to a social media post by a communications director for Meta, which owns both platforms. In the same post, though, the Meta official noted that the company’s enforcement of this rule has been “incorrect” in some cases.
“It’s terrifying to think that arbitrary decisions by these platforms can dramatically limit the ability of people to access critical reproductive rights information,” Kleinman says. However, he adds, “as it currently stands, the platforms make unilateral decisions about what reproductive rights information they allow and what information they take down.”