Non-invasive diagnostics such as optical scans and swabs are increasingly being used to diagnose disease in people. Now EU-backed scientists are trying to extend the techniques to the treatment of companion animals.
An estimated 90 million dogs live as pets in European homes. Having a dog in the family can make people more physically active. It can reduce feelings of isolation and loneliness. It can also improve the lives of older people – petting a dog has been shown to help lower blood pressure.
But even though there is a living dog in almost 40% of European homes, there is a relatively minor problem. Capnocytophaga canimorsus is a bacterium that lives in the saliva of dogs and can infect humans and cause serious illness.
Although it lives in the mouths of dogs and cats harmlessly most of the time, on rare occasions if a dog bites or licks a cut, certain strains of the microbe can trigger a devastating illness in humans.
The condition is rare, with around four cases per million population per year. As difficult to treat as it is to pronounce, Capnocytophaga canimorsus can pass from a dog’s saliva into a person’s blood when a dog licks a scratch or abrasion.
“The name is canimorsus, which means dog bite in Latin,” said Dr Francesco Renzi, a microbiologist at the University of Namur, Belgium, “and that’s clearly the main route of infection.”
Capnocytophaga canimorsus almost never causes disease in healthy young people. However, it can cause serious illness in people with weakened immune systems, those with damaged or missing spleens, and people suffering from alcoholism.
“People over 60 are also at higher risk, possibly due to their immune status,” Dr Renzi said.
The number of bacteria in the blood can increase and cause high fever, flu-like symptoms and pain. “There are no specific symptoms and the infection is quite rare,” Dr Renzi said. This makes it less likely for a doctor to suspect an infection with these bacteria.
About 30% of cases result in death, and many of those who survive suffer amputation due to gangrene. A patient may also suffer from sepsis and multiple organ failure.
While antibiotics, given early, kill the microbe, identifying Capnocytophaga canimorsus can be very difficult, even in hospital laboratories.
“What’s important is for doctors to talk to patients and ask them if they have a dog, if they’ve been bitten recently,” Dr. Renzi said. A bite may not become infected, so it is not obvious that the infection entered that way.
Dr. Renzi’s Belgian laboratory collected saliva from 285 dogs and identified Capnocytophaga canimorsus in 83% of them using a PCR test they developed for the CANITEST project.
They also established that the most harmful bacterium that causes the majority of human illnesses is present in only about 10% of dogs.
Dr Renzi advises dog owners in the 88 million European households where dogs live, to wash themselves after contact with their pet’s saliva and not to let a dog lick an open wound or cut.
Dr. Blaž Cugmas is a young researcher whose great passion in life is to improve animal health. He is particularly interested in how technology can be used by veterinarians to diagnose and treat companion animals.
After completing his PhD in his native Slovenia, Dr. Cugmas moved to a lab in Riga, Latvia renowned for biophotonics.
Biophotonics is a light-based method used in medicine, for example when smartphone cameras are used to scan skin lesions for cancer.
“Most of these technologies were developed for humans,” Dr. Cugmas said, “and they can’t just be transposed to animals.”
The challenge was how to use biophotonics to diagnose disease in companion animals.
Dr. Cugmas set out to develop technologies and prototypes that veterinarians could use on animal patients as part of the dogSPEC project.
Today, anyone can buy pulse oximeters, a device that sends light through a finger to a sensor on the other side. It detects the color of the blood and thus calculates the oxygen levels in the blood. A dramatic drop in blood oxygen, for example, can indicate a serious illness.
Dr. Cugmas applied his prototype pet pulse oximeter to various locations around the bodies of cats and dogs to test the animals’ condition.
“We’ve shown that there are certain places where you can apply a pulse oximeter and get a strong signal,” he said. This could be used by a veterinarian to help diagnose disease, to validate with other tests. A faster diagnosis will lead to better outcomes for our furry friends.
Another diagnostic device that people use, but not normally pets, is an infrared thermometer. This is often used to measure the body temperature of children when held close to their forehead. The devices have become widely familiar since being used to check people’s temperatures under Covid-19 pandemic conditions.
Such a pet device would be incredibly useful, Dr. Cugmas said, because normally a veterinarian would apply a thermometer to their patient’s rectum.
‘As you can imagine, it’s not very popular with the animal. Cats, in particular, don’t tolerate this very well,” he said. Dr. Cugmas is trying to develop a portable infrared thermometer suitable for pets. He also has a license to practice as a veterinarian.
It’s a very practical challenge. Ideally, taking the temperature would be the start of a clinical exam, but many vets avoid it, “because you irritate the animal so much that you lose their cooperation,” Dr. Cugmas said.
Redness of the skin
Dr. Cugmas is also developing a portable pet dermatoscope. This device would use light to assess the redness, or erythema, of an animal’s skin.
In humans, a dermatoscope is used by medical specialists to scan for marks that could signal skin cancer with melanoma.
While dogs and cats rarely get skin cancer, changes in skin color can be markers of serious disease. For example, a dog’s skin may become red and itchy if he has an allergic reaction.
“We’re trying to use smartphone cameras, which have a mobile dermatoscope attached, to try to measure skin erythema,” Dr. Cugmas said. It demonstrated its potential in a study of 43 dogs with cutaneous dermatitis in January 2021.
Dog proof devices
Work is underway to physically strengthen the devices, as some excitable dogs have in the past knocked over the prototypes and damaged them. In addition, given the nature of the patient, it is important to make the devices resistant to chewing.
Professor Janis Spigulis is a physicist working in the same biophotonics laboratory in Riga. He praises his colleague’s work in transferring light-based diagnostic technology to companion animals.
“Blaž tries to stick to the same approaches and make animal-specific devices,” he said.
“Many optical technologies are unknown to veterinarians, so this interdisciplinary interaction is very positive and he has achieved good results.”
The research in this article was funded by the EU. This article originally appeared in Horizon, the European research and innovation magazine.