Abstract
Molecular tests for viral diagnostics are essential to confront the COVID-19 pandemic, but their production and distribution cannot satisfy the current high demand. Early identification of infected people and their contacts is the key to being able to isolate them and prevent the dissemination of the pathogen; unfortunately, most countries are unable to do this due to the lack of diagnostic tools. Dogs can identify, with a high rate of precision, unique odors of volatile organic compounds generated during an infection; as a result, dogs can diagnose infectious agents by smelling specimens and, sometimes, the body of an infected individual. We trained six dogs of three different breeds to detect SARS-CoV-2 in respiratory secretions of infected patients and evaluated their performance experimentally, comparing it against the gold standard (rRT-PCR). Here we show that viral detection takes one second per specimen. After scent-interrogating 9,200 samples, our six dogs achieved independently and as a group very high sensitivity, specificity, predictive values, accuracy, and likelihood ratio, with very narrow confidence intervals. The highest metric was the negative predictive value, indicating that with a disease prevalence of 7.6%, 99.9% of the specimens indicated as negative by the dogs did not carry the virus. These findings demonstrate that dogs could be useful to track viral infection in humans, allowing COVID-19 free people to return to work safely.
Competing Interest Statement
The authors have declared no competing interest.
Footnotes
Professor Omar Vesga, MD. Head and Attending Physician, Section of Infectious Diseases, Hospital Universitario San Vicente Fundación. Director GRIPE and Professor of Medicine, University of Antioquia Medical School.
Andrés F. Valencia, DVM. Director of Training, Colina K-9. Assistant Researcher GRIPE.
Alejandro Mira, DVM. Trainer, Colina K-9. Assistant Researcher GRIPE.
Felipe Ossa. Trainer, Colina K-9. Undergraduate student (Veterinary Medicine), GRIPE, University of Antioquia.
Esteban Ocampo. Trainer, Colina K-9.
Maria Agudelo, MD, PhD. Attending Physician, Section of Infectious Diseases, Hospital Universitario San Vicente Fundación. Scientific Director, GRIPE, University of Antioquia.
Karl Čiuoderis, DVM - PhD (cand.). Associate Scientist, Colombia/Wisconsin One-Health Consortium, Universidad Nacional de Colombia, Sede Medellin
Laura Perez, M.Sc. Biology. Associate Scientist, Colombia/Wisconsin One-Health Consortium, Universidad Nacional de Colombia, Sede Medellin
Andres Cardona, M.Sc. Biology. Associate Scientist, Colombia/Wisconsin One-Health Consortium, Universidad Nacional de Colombia, Sede Medellin
Yudy Aguilar, PhD (cand.). Associate Scientist, GRIPE, University of Antioquia.
Javier González, MD. Associate Scientist, GRIPE, University of Antioquia.
Juan C. Cataño, MD. Associate Scientist, GRIPE, University of Antioquia.
Yuli Agudelo, MD. Director of Clinical Management, Hospital Universitario San Vicente Fundación, sede Medellín.
Professor Juan P. Hernández-Ortiz, PhD. Director Colombia/Wisconsin One-Health Consortium, Universidad Nacional de Colombia, Sede Medellín.
Professor Jorge E. Osorio, DVM, PhD. Director Colombia/Wisconsin One-Health Consortium, University of Wisconsin-Madison.