Summary: New research suggests that scent dogs may provide a faster and more efficient way to detect COVID-19, even outperforming conventional RT-PCR tests.
In studies involving over 31,000 samples, dogs were able to identify COVID-19 in symptomatic, pre-symptomatic, and asymptomatic individuals, as well as detect new variants and long COVID. Beyond their impressive sensitivity, the dogs could deliver results quickly without the need for expensive lab equipment.
This discovery could pave the way for the use of scent dogs in rapid health screenings during pandemics.
Key Facts:
- Scent dogs demonstrated similar or better sensitivity and specificity in COVID-19 detection compared to standard RT-PCR tests.
- Dogs can detect COVID-19 in all stages, from pre-symptomatic and asymptomatic individuals to those with new variants and long COVID.
- Scent dogs offer rapid results, providing a significant advantage over traditional testing methods that require costly lab equipment and produce plastic waste.
Source: De Gruyter
Scent dogs may represent a cheaper, faster and more effective way to detect COVID-19, and could be a key tool in future pandemics, a new review of recent research suggests.
The review, published in De Gruyter’s Journal of Osteopathic Medicine, found that scent dogs are as effective, or even more effective, than conventional COVID-19 tests such as RT-PCR.
Dogs possess up to 300 million olfactory cells, compared to just 5 or 6 million in humans, and use one-third of their brains to process scent information, compared with just 5% for humans. Dogs trained to recognize specific volatile organic compounds created in the body during disease have successfully identified patients with certain cancers, Parkinson’s and diabetes.
Prof. Tommy Dickey of the University of California, Santa Barbara and Heather Junqueira of BioScent Detection Dogs reviewed 29 studies where dogs were used to detect COVID-19. The studies were performed using over 31,000 samples by over 400 scientists from more than 30 countries using 19 different dog breeds.
In some studies, the scent dogs sniffed people directly, sometimes in public places as a health screening. In others, the dogs sniffed patient samples such as sweat, saliva or urine samples.
In the majority of studies, the scent dogs demonstrated similar or better sensitivity and specificity than the current gold-standard RT-PCR tests or antigen tests. In one study, four of the dogs could detect the equivalent of less than 2.6 x 10−12 copies of viral RNA per milliliter.
This is equivalent to detecting one drop of any odorous substance dissolved in ten and a half Olympic-sized swimming pools and is three orders of magnitude better than modern scientific instruments.
The dogs could detect COVID-19 in symptomatic, pre-symptomatic and asymptomatic patients, along with new COVID variants and even long COVID.
A major benefit of using the dogs was their speed – they could provide a result in seconds to minutes, and did not require expensive lab equipment or create mountains of plastic waste, unlike conventional diagnostic approaches.
“Although many people have heard about the exceptional abilities of dogs to help humans, their value to the medical field has been considered fascinating, but not ready for real-world medical use,” said Prof. Dickey.
“Having conducted this review, we believe that scent dogs deserve their place as a serious diagnostic methodology that could be particularly useful during pandemics, potentially as part of rapid health screenings in public spaces. We are confident that scent dogs will be useful in detecting a wide variety of diseases in the future.”
Prof. Dickey and Heather Junqueira added that they feel that the impressive international COVID scent dog research described in their paper, perhaps for the first time, demonstrates that medical scent dogs are ready for mainstream medical applications.
About this olfaction research news
Author: Mauricio Quiñones
Source: De Gruyter
Contact: Mauricio Quiñones – De Gruyter
Image: The image is credited to Neuroscience News
Original Research: Open access.
“COVID-19 scent dog research highlights and synthesis during the pandemic of December 2019−April 2023” by Tommy Dickey et al. Journal of Osteopathic Medicine
Abstract
COVID-19 scent dog research highlights and synthesis during the pandemic of December 2019−April 2023
Context
This review was undertaken to provide information concerning the advancement of research in the area of COVID-19 screening and testing during the worldwide pandemic from December 2019 through April 2023. In this review, we have examined the safety, effectiveness, and practicality of utilizing trained scent dogs in clinical and public situations for COVID-19 screening. Specifically, results of 29 trained scent dog screening peer-reviewed studies were compared with results of real-time reverse-transcription polymerase chain reaction (RT-PCR) and rapid antigen (RAG) COVID-19 testing methods.
Objectives
The review aims to systematically evaluate the strengths and weaknesses of utilizing trained scent dogs in COVID-19 screening.
Methods
At the time of submission of our earlier review paper in August 2021, we found only four peer-reviewed COVID-19 scent dog papers: three clinical research studies and one preprint perspective paper. In March and April 2023, the first author conducted new literature searches of the MEDLINE/PubMed, Google Scholar, and Cochrane Library websites. Again, the keyword phrases utilized for the searches included “COVID detection dogs,” “COVID scent dogs,” and “COVID sniffer dogs.”
The Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA) 2020 Checklist was followed to ensure that our review adhered to evidence-based guidelines for reporting. Utilizing the results of the reviewed papers, we compiled statistics to intercompare and summarize basic information concerning the scent dogs and their training, the populations of the study participants, the types of sampling methods, the comparative tests utilized, and the effectiveness of the scent dog screening.
Results
A total of 8,043 references were identified through our literature search. After removal of duplicates, there were 7,843 references that were screened. Of these, 100 were considered for full-text eligibility, 43 were included for qualitative synthesis, and 29 were utilized for quantitative analysis. The most relevant peer-reviewed COVID-19 scent dog references were identified and categorized. Utilizing all of the scent dog results provided for this review, we found that 92.3 % of the studies reached sensitivities exceeding 80 and 32.0 % of the studies exceeding specificities of 97 %. However, 84.0 % of the studies reported specificities above 90 %.
Highlights demonstrating the effectiveness of the scent dogs include: (1) samples of breath, saliva, trachea-bronchial secretions and urine as well as face masks and articles of clothing can be utilized; (2) trained COVID-19 scent dogs can detect presymptomatic and asymptomatic patients; (3) scent dogs can detect new SARS-CoV-2 variants and Long COVID-19; and (4) scent dogs can differentiate SARS-CoV-2 infections from infections with other novel respiratory viruses.
Conclusions
The effectiveness of the trained scent dog method is comparable to or in some cases superior to the real-time RT-PCR test and the RAG test. Trained scent dogs can be effectively utilized to provide quick (seconds to minutes), nonintrusive, and accurate results in public settings and thus reduce the spread of the COVID-19 virus or other viruses. Finally, scent dog research as described in this paper can serve to increase the medical community’s and public’s knowledge and acceptance of medical scent dogs as major contributors to global efforts to fight diseases.
