Researchers in Germany suggest that spy dogs should be considered as an additional screening tool for the detection of infections with severe acute respiratory coronavirus 2 (SARS-CoV-2) syndrome – the causes coronavirus disease 2019 (COVID-19).
The team found that dogs could discriminate between saliva samples from people with and without SARS-CoV-2 infection with 84% sensitivity and 95% specificity.
The dogs were also able to detect the smell of SARS-CoV-2 infection in sweat and urine samples, with sensitivity and specificity as high as 95% and 98%, respectively, for urine samples.
Holger Andreas Volk from Hannover Medical University in Bünteweg and colleagues say the results suggest that spy dogs could be added to the standard gold standard method for detecting SARS-CoV-2.
The team advises that dogs should be considered for a quick test in a variety of situations where large numbers of people of different backgrounds come together, such as airports or receptions.
A pre-printed version of the research paper can be found on the bioRxiv* server, while the article is subject to peer review.
The standard procedures for the administration of COVID-19
The main method of COVID-19 pandemic disease is testing, detection and quarantine while sufficient vaccines are administered to protect a sufficient proportion of the population.
The SARS-CoV-2 virus is currently being detected using “gold standard” polymerase reabsorption (RT-PCR) chain reaction and slightly more sensitive but faster tests of nasal or pharyngeal swabs and saliva.
However, “it is not clear whether sweat or urine are also sources of viral transmission,” says Volk and his colleagues.
How do Dogs Find Infection?
Renowned for their amazing olfactory senses, dogs are often used to detect drugs and explosives in real time, for example.
Infectious diseases can produce specific odors through the generation of organic organic fertilizers (VOCs) – the products of metabolism released in the breath, saliva, sweat and urine.
Multiple studies have shown that dogs can detect infectious and non-infectious diseases such as cancer, malaria, bacterial infection, hypoglycemia in diabetics, and viral infection in cell cultures.
Several research groups are currently training and using dogs for the detection of SARS-CoV-2 infection.
In a pilot study, Volk and colleagues recently showed that dogs were able to detect inactive saliva samples from COVID-19 patients with 83% sensitivity and 96% specificity.
However, it remains to be seen whether dogs can detect specific biofluid VOCs or more broadly alter the odor of COVID-19 patients.
What did the current study cover?
In the previous pilot study, only active beta-propiolactone (BPL) samples from COVID-19 patients were used.
“The first step in the current study, therefore, was to assess whether dogs can transfer odor recognition to inactive saliva samples, even when trained with inactive samples only,” said Vol and colleagues.
Ten German military force service dogs were trained for a period of 8 days to identify the infectious odor of SARS-CoV-2 using inactive saliva samples BPL. The researchers then tested whether the identified animals could transfer odors to saliva, urine and inactive sweat samples from infected patients.
The animals identified odors of SARS-CoV-2 infection with 95% and 98% sensitivity and specificity, respectively, for urine samples, 91% and 94% for sweat samples, and 82% and 96% for saliva samples.
“After just eight days of training, dogs could not only shift their odor detection capabilities from inactive saliva samples to inactive, but also to sweat and urine, with urine with the highest sensitivity. of 95% and specificity of 98%, ”the team wrote.
The researchers say the findings show that SARS-CoV-2-specific, non-specific global VOCs are released across different body resolutions.
What does the team advise?
The current study suggests that dogs can be safely trained within just over a week to become reliable SARS-CoV-2 test dogs, say volk and colleagues.
“Spy dogs should be considered as an addition to the RT-PCR gold standard, for rapid testing in situations where large numbers of people of different origins come together,” they write.
“More work is needed, especially under a day-to-day situation in situations where many people need to be screened to fully assess the feasibility of the dog detection method,” the team concluded.
* Important message
bioRxiv publish preliminary scientific reports that are not peer-reviewed and, therefore, should not be seen as final, guiding health-related clinical / behavioral practice, or be treated as information established.