A new study further supports the theory that dogs can be trained to detect the presence of SARS-CoV-2, or the COVID-19.
A research team from Germany used eight detection dogs from the German Bundeswehr. The canines were trained for a week to detect saliva, or tracheobronchial secretions, from SARS-CoV-2 positive patients. Patients are those who previously tested positive for the infection based on nasopharyngeal swab samples. The dogs were subjected to a randomized, double-blinded, and controlled study setup.
The team was led by the University of Veterinary Medicine Hannover through BMC Veterinary Research Section Editor Professor Holger Volk.
Scent Dog Identification Results
After the testing, the research team determined that the dogs were able to discriminate between positive and negative samples. The average diagnostic sensitivity from the German study was 82.63 percent, at a 95 percent confidence interval.
However, the study reveals that trained dogs are better at detecting COVID-negative individuals compared to those who are positive with the infection. Across their 1,012 randomized samples, the dogs posted an overall detection rate of 94 percent (±3.4 percent error). The detection rate had an 83 percent success rate from infected secretions and a 96 percent success rate with control secretions.
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In the detected instances, 157 were correct indications of positive cases while 792 were correct rejections of negative cases. However, there were still 30 incorrect rejections of positive samples and 33 incorrect indications of negative samples.
Despite the positive and promising results of the detection dogs, further studies are still required. Their samples were only classified based on the presence of the SARS-CoV-2, not stratified by criteria such as the severity of symptoms, status of the disease from the individual, or viral load of the samples.
In fact, for succeeding studies, the German-led team recommends the use of a larger sample population, to capture analytical sensitivity. The larger population could also isolate incidents of SARS-CoV-2 presence with other respiratory diseases or phenotypes of the COVID-19.
Canine Screening Procedure For COVID-19
The University of Veterinary Medicine Hannover study supports earlier pilot tests studies from other institutions regarding the potential of dogs as a SARS-CoV-2 screening agent. Back in April, the University of Pennsylvania School of Veterinary Medicine (Penn Vet) launched its pilot training program to train detection dogs in discriminating SARS-CoV-2.
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Penn Vet also set up their study with eight dogs, trained over three weeks in odor imprinting. The dogs are exposed to COVID-19 positive saliva and urine samples in a laboratory. Regarding the study with the scent-detecting dogs, Penn Vet was supported by the US Army Combat Capabilities Development Command Chemical Biological Center.
Dr. Cynthia Otto, professor of Working Dog Sciences and Sports Medicine and Penn Vet Working Dog Center Director, noted that scent detection dogs can "accurately detect low concentrations of volatile organic compounds". VOCs are often associated with bacterial infections, as well as other medical conditions and are present in most human fluids--urine, breath, saliva, and even blood.
"Penn Vet is a key part of the biomedical community here at the University of Pennsylvania. We are leveraging our unique and collective expertise in pathogen-related research, infectious disease, and translational medicine to fight this pandemic," said Dr. Philip Scott, vice dean for Research and Academic Resources.
