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PLoS One

Title:		Highly sensitive scent-detection of COVID-19 patients in vivo by trained dogs
Author(s):		Vesga O; Agudelo M; Valencia-Jaramillo AF; Mira-Montoya A; Ossa-Ospina F; Ocampo E; Ciuoderis K; Perez L; Cardona A; Aguilar Y; Agudelo Y; Hernandez-Ortiz JP; Osorio JE;
Address:		"Section of Infectious Diseases, Hospital Universitario San Vicente Fundacion, Medellin, Colombia. GRIPE, Universidad de Antioquia, Medellin, Colombia. Colina K-9, La Ceja, Colombia. Undergraduate School of Veterinary Medicine, Universidad de Antioquia, Medellin, Colombia. Colombia/Wisconsin One-Health Consortium, Departamento de Materiales, Facultad de Minas, Universidad Nacional de Colombia, Sede Medellin, Colombia. Department of Pathobiology, School of Veterinary Medicine, University of Wisconsin, Madison, WI, United States of America"
Journal Title:		PLoS One
Year:		2021
Volume:		20210929
Issue:		9
Page Number:		e0257474 -
DOI:		10.1371/journal.pone.0257474
ISSN/ISBN:		1932-6203 (Electronic) 1932-6203 (Linking)
Abstract:		"Timely and accurate diagnostics are essential to fight the COVID-19 pandemic, but no test satisfies both conditions. Dogs can scent-identify the unique odors of volatile organic compounds generated during infection by interrogating specimens or, ideally, the body of a patient. After training 6 dogs to detect SARS-CoV-2 by scent in human respiratory secretions (in vitro diagnosis), we retrained 5 of them to search and find the infection by scenting the patient directly (in vivo screening). Then, efficacy trials were designed to compare the diagnostic performance of the dogs against that of the rRT-PCR in 848 human subjects: 269 hospitalized patients (COVID-19 prevalence 30.1%), 259 hospital staff (prevalence 2.7%), and 320 government employees (prevalence 1.25%). The limit of detection in vitro was lower than 10-12 copies ssRNA/mL. During in vivo efficacy experiments, our 5 dogs detected 92 COVID-19 positive patients among the 848 study subjects. The alert (lying down) was immediate, with 95.2% accuracy and high sensitivity (95.9%; 95% C.I. 93.6-97.4), specificity (95.1%; 94.4-95.8), positive predictive value (69.7%; 65.9-73.2), and negative predictive value (99.5%; 99.2-99.7) in relation to rRT-PCR. Seventy-five days after finishing in vivo efficacy experiments, a real-life study (in vivo effectiveness) was executed among the riders of the Metro System of Medellin, deploying the human-canine teams without previous training or announcement. Three dogs were used to examine the scent of 550 volunteers who agreed to participate, both in test with canines and in rRT-PCR testing. Negative predictive value remained at 99.0% (95% C.I. 98.3-99.4), but positive predictive value dropped to 28.2% (95% C.I. 21.1-36.7). Canine scent-detection in vivo is a highly accurate screening test for COVID-19, and it detects more than 99% of infected individuals independent of key variables, such as disease prevalence, time post-exposure, or presence of symptoms. Additional training is required to teach the dogs to ignore odoriferous contamination under real-life conditions"
Keywords:		Animals COVID-19/*diagnosis Dogs Female Humans Male Mass Screening Odorants/*analysis Pheromones/*analysis Predictive Value of Tests SARS-CoV-2/pathogenicity Sensitivity and Specificity Volatile Organic Compounds Working Dogs;
Notes:		"MedlineVesga, Omar Agudelo, Maria Valencia-Jaramillo, Andres F Mira-Montoya, Alejandro Ossa-Ospina, Felipe Ocampo, Esteban Ciuoderis, Karl Perez, Laura Cardona, Andres Aguilar, Yudy Agudelo, Yuli Hernandez-Ortiz, Juan P Osorio, Jorge E eng 2021/09/30 PLoS One. 2021 Sep 29; 16(9):e0257474. doi: 10.1371/journal.pone.0257474. eCollection 2021"