Labrador Retrievers are known for being adorable and friendly, but they also make very good detective dogs. Now, a Labrador Retriever can be trained to help detect people infected with Covid-19.
In a collaboration with Chevron Thailand, PQA Associates and the Faculty of Veterinary Science, Chulalongkorn University, six Labrador Retrievers have been trained to detect Covid-19 carriers. As part of their training, the dogs sniff several sweat samples in safe glass containers and sit down in front of the container containing Covid-19.
The main objective of the sniffer dogs project is to screen people who have asymptomatic Covid-19 or people who show no symptoms. Prof Dr Kaywalee Chatdarong, deputy dean for Research and Innovation at the Faculty of Veterinary Science, CU, said using sniffer dogs as screening tools costs less than a PCR test, which ranges between 1,500 to 8,000 baht.
"The investment involves canines, dog trainers and sample containers. Each dog can sniff between 100 to 200 samples per day. The average price for screening one sample is up to 100 baht. The six Labrador Retrievers have been trained by PQA Associates but the experiment was designed and overseen by the Faculty of Veterinary Science of CU. If the project is successful, people at Chevron Thailand will use the dogs to screen Covid-19 carriers among their staff who depart for offshore locations in Songkhla," said Prof Dr Kaywalee.
A dog sits down in front of a sweat sample of a person infected with Covid-19.
The idea of the project was inspired by news regarding sniffer dogs trained to detect Covid-19 overseas. Canines are used to detect the coronavirus because their sense of smell is 50 times better than humans.
"We chose to train Labrador Retrievers because they are alert and friendly. When we bring them to work at other places, people are not afraid of them. Labrador Retrievers have long nasal cavities, which is helpful. These six dogs were trained every day for four hours a day. On days that they do not want to work, trainers do not force them. Dogs are allowed to take breaks. We are careful to avoid stressing them," said Kingkan Kaewfun, project manager of PQA Associates.
Since coronavirus is an infectious disease, the safety of the dogs is a concern. However, Prof Dr Kaywalee said the dogs are not at risk because the project uses sweat samples and the coronavirus is not transmitted through sweat.
"According to studies, sweat does not contain coronavirus, but the virus can be passed on through touch. To ensure safety, samples are stored in a biosafety laboratory. Since the virus can survive on cotton for 24 hours, cotton with sweat samples are kept in the lab for 48 hours before being sent to the training area in Songkhla," explained Prof Dr Kaywalee.
The 'Dom VVI' mobile laboratory.
The six Labs were trained in September last year. By smelling the various cotton swabs, they learned to differentiate between the sweat of people infected with Covid-19 and the sweat of the non-infected.
"In a blind test, dogs sniffed sweat samples stored in containers. When they detected the sweat of an infected person, they immediately sit down," said Kingkan.
The research considers the sensitivity, specificity and accuracy of the dog's ability to detect positive samples. The overall accuracy during the first and second waves of the coronavirus in Thailand was about 96%. Because of that limited success, researchers at the Faculty of Veterinary Science of CU cooperated with researchers at the Faculty of Engineering to design the mobile laboratory "Dom VVI" to allow the dogs to work in other areas.
"When we took the dogs to screen people at clusters and wanted real-time results, we needed to find a space. The mobile laboratory was designed to be their working space, so the dogs and trainers could stay in a safe area and not get infected. The dogs were trained to work inside the mobile laboratory and their accuracy in detecting positive samples was similar to that on the ground," said Prof Dr Kaywalee.
Even though the screening results of trained dogs showed high accuracy, Prof Dr Kaywalee does not recommend using the results on its own.
A Labrador Retriever sniffs several sweat samples in safe containers.
"The project is a screening test. Coronavirus is an infectious disease and a pandemic. If a dog detects a positive sample, that person should undergo PCR test again," said Prof Dr Kaywalee, noting that in July, the dogs' detection accuracy dropped to 60-65%.
"The dogs do not smell the virus but detect cells that are damaged by the virus. We once had a dog sit down after detecting a sample from a former Covid-19 patient who had the coronavirus a month ago. There are many confounding factors that affect recent sweat samples, including vaccines and variants," said Prof Dr Kaywalee.
To solve the problem, CU researchers are retraining the dogs to account for these new variables, she added.
While the dogs are being retrained, CU researchers have modified a handheld gas analyser to screen sweat samples.
"The handheld gas analyser's capacity to screen and detect sweat samples has an accuracy rate similar to a PCR test," Prof Dr Kaywalee said. Researchers currently have one machine but expect to have three in the near future, she added.
Kaywalee believes that the sniffer dog project will be a model for biomedical dog projects in the future.
Inside the 'Dom VVI' mobile laboratory.
"We have gained knowledge training dogs to detect other diseases such as diabetes, lung cancer and epilepsy. Reports abroad state that dogs can warn patients with epilepsy 60 minutes before a seizure occurs. We can train dogs to help warn patients. These projects are possible but we need financial resources in order to train new dogs with patient sample cases," added Prof Dr Kaywalee.
