Sniffer dogs and covid 19 detection
July 29, 2022Covid 19
Could sniffer dogs at public events provide us with another level of bio secruity along with lateral flow tests and PCR tests. According to a sniffer dog covid 19 trail.
A study by the BMJ International believe there is good merit in deploying sniffer dogs. While the dogs did have a higher degree of false postives, the did have an overall accurary rate close to higher than the PCR test.
Dogs have an extremely acute sense of smell, and can pick up a scent at levels as low as one part per trillion. While Covid has a unique smell to dogs. Dogs detect distinct volatile organic compounds released during various metabolic functions in the body. Especially those that are generated by bacterial, viral, and parasitic infections.
Preliminary data suggest that dogs can be trained within weeks to detect samples from patients with COVID-19 infection. The degree of accuracy comparable to that of a standard PCR nose and throat swab test and of course lateral flow tests.
The researchers, trained 4 dogs to sniff out SARS-CoV-2 in Spring 2020. Each of the dogs had previously been trained to sniff out illicit drugs or dangerous goods or cancer.
420 volunteers provided four skin swab samples each. The 4 dogs each sniffed the skin samples from 114 of the covid 19 positive volunteers and from 306 who had tested negative.
The samples were randomly presented to each dog over 7 trial sessions.
The diagnostic accuracy of all samples sniffed was 92%: combined sensitivity
- accuracy of detecting those with the infection—was 92% -Combined specificity—accuracy of detecting those without the infection—was 91%.
Variations was seen among the sniffer dogs: the best performance reached 93% for sensitivity and 95% for specificity; the worst reached 88% for sensitivity and 90% for specificity.
28 of the positive samples came from people who had had no symptoms. One was incorrectly identified as negative and two weren’t sniffed. meaning that 25 of the 28 (just over 89%) were correctly identified as positive. The lack of symptoms didn’t seem to affect the dogs’ performance.
The 4 dogs were then put to work sniffing out 303 incoming passengers at Helsinki-Vantaa International Airport, Finland, between September 2020 and April 2021. Each passenger also took a PCR swab test.