Research: dogs can sniff out different coronavirus strains

Researchers at a vet school in Germany have discovered dogs can differentiate SARS-CoV-2 virus samples from 15 other viral respiratory pathogens with high specificity.

The study conducted at the University of Veterinary Medicine Hanover found dogs were able to discriminate between SARS-CoV-1, SARS-CoV-2, Middle East respiratory syndrome and other coronaviruses, including those responsible for the common cold.

Test scenarios

Holger Volk – specialist veterinary neurologist, and department chairman of small animal medicine and surgery at the vet school – detailed how the research could lead to dogs being used to screen visitors at live events.

Prof Volk said: “It’s very exciting; I mean, this is just another cornerstone that proves that dogs are amazing and obviously are able to potentially detect viruses.”

Three test scenarios were performed. In the first, dogs trained with inactivated saliva samples of SARS-CoV-2 discriminated between the virus and swab samples from patients infected by other respiratory tract infections. There was a mean sensitivity of 74% and a specificity of 95%.

In the second test scenario, cell cultures consisting of human cells to which the various pathogens had been added, were used.

Researchers found dogs trained with inactivated saliva samples of SARS-CoV-2 patients were able to also differentiate between cell cultures of the different respiratory viruses.

In the final scenario, dogs were trained with inactivated cell culture material of SARS‑CoV‑2 and performed much as they did in the first.

Short training period

Other viral pathogens used in the study included Influenza A and B, human respiratory syncytial virus, metapneumovirus, human parainfluenza virus types one and three, rhinovirus, adenovirus and human coronaviruses.

Prof Volk said: “In this experiment, for various reasons, we had to deploy these dogs quickly so we had only a very short training period, and still, they did quite okay. I think the sensitivity would only have gone up if we had trained them for longer.

“The other thing I learned in this is that, when the trainer was somehow informed of the nature of the test, then the dog wouldn’t do well, but if we just let the dog do what they will, they did amazingly.”

Study

The study, set to be published in the journal Frontiers in Medicine, used 12 scent detection dogs provided by the German armed forces, as well as private companies. Some of the dogs had previously been trained in sniffing out explosives, but the study also included dogs with no training.

Detailing the device used to test the dogs, Prof Volk said: “It’s like a sniffing machine with several holes, and you can randomise between each hole and everything, meaning you have a lot of possible variations every time.

“They have to learn to put their nose into the hole, and if they do that for longer than two seconds they get a treat. Because of that, they just learn really first, it is just fun.”

Event visitor screening

The same researchers have also announced they will soon be following up their study with another report into a series of trials involving the use of COVID‑19 sniffer dogs at music concerts.

Prof Volk explained: “We had four music concerts of multiple thousands of people, and we looked to see if we could compare an antigen test done in a centre, a proper antigen test, a PCR test and the dogs at the same time, including looking at different ways of how we compare the dogs’ searching behaviour.

“The main aim of the study was to deploy the dogs in a real-life scenario and actually see if it is feasible.

“We always say that dogs are cheaper – and more environmentally friendly – but then the question is how would this function work in the real world if you were to actually deploy them?

“We always talk about the environment – I don’t know how it is in the UK, but here [in Germany] we have to test every two days. The rubbish I create, and these lateral flow tests can sometimes be so unreliable.”

Prof Volk concluded: “In the UK, I could see them being deployed, but personally, in Germany and most countries [in the EU], you won’t see them directly sniffing a person.

“I could see them being used in a scenario such as care homes – you could use the dogs to do a quick screening in the morning at multiple care homes or screen multiple schools.”