Browsing by Author "Heiskanen, Elina"

Scent detection dogs have been used worldwide for a long time in search and rescue by police forces and civilian services. In the past years there have been multiple studies suggesting that dogs could be able to detect different cancers by smelling samples from diseased persons. In 2019 an acute respiratory disease started spreading from China, causing the COVID-19 pandemic. It has been contemplated if dogs could detect COVID-19 infected individuals from different kind of samples with promising results. This thesis literature review is about the canine sense of smell, volatile organic compounds (VOCs), the COVID-19 pandemic and scent detection dogs. The thesis also contains a study part that aimed to evaluate how sensitive and specific dogs are at detecting COVID-19 from skin swipe samples. It is suggested that dogs could be used as a screening tool to detect COVID-19 infected samples. We collected 114 samples from COVID-19 positive patients and 306 COVID-19 negative patients who all had official PCR result and answered an electronic survey about symptoms, diet, state of health and vaccination status. We trained four dogs to detect COVID-19 positive samples. The overall sensitivity was 91.8% and specificity 91.4%. This study overcomes some of the limitations of the previous studies. Still, also this study had some difficulties. Virus variants started to emerge in Finland at the end of our validation sample collection period. Because of that, the last two validation days did not succeed as well as the first five. In some cases, dog’s marking was not clear, leading to wrong result since the handler was the one to interpret the dogs marking and declared it. Some dogs had difficulties with marking empty line-ups. Because of these difficulties it is essential that the handler interprets the dog’s sign accurately and teach clear indication for positive and negative samples to avoid this source of error. As a conclusion we can say that these scent detection dogs had a high diagnostic sensitivity and specificity suggesting that dogs could be able to detect COVID-19 positive individuals and could be used as a COVID-19 screening method. However, more research needs to be done since it is still unknown what dogs smell and there are no standardized methods for these studies.