CHENNAI: With the Indian Army and several countries engaging dogs to detect Covid-19 infection in human beings, the big question is if the method can be adopted by Indian States.
A study published in a peer-reviewed journal, PLOS One, said that trained dogs can detect, with a high degree of accuracy, asymptomatic and mild Covid-19 infections in human beings by body odour under laboratory conditions.
The paper, published by researchers from the University of Pennsylvania and other collaborators, stated that the sniffer-dog strategy has the potential to screen large groups of people rapidly, accurately, and non-invasively.
In an interview with Express, Madras Veterinary College Professor Dr P Selvaraj, also a sniffer-dog medical researcher, tells how the method can be a cost-effective and time-saving tool to arrive at accurate results.
How do they have the capacity to sniff infections?
An infection in a human or a animal body will alter the metabolism, leading to the production of certain chemicals. These chemicals may release ‘odour signatures’ that can be picked up by a trained medical-detective dog.
How do they know that they have to flag a particular smell?
A sniffer dog is given meticulous training from a young age itself and is exposed to a particular smell. Once trained, these dogs will retain their odour-memories.
How do dogs convey if a sample is positive?
They will do a pawing gesture or sit where the suspected item is or bark. It indicates an abnormal smell is coming from a particular sample/suspected items.
How are such testing dogs categorised?
The common name is service dogs. Under that, there are detective dogs and guide dogs. Under the detective category, there are security-detective dogs and medical-detection dogs.
Some of the health conditions or diseases that dogs can detect?
Cancers (lung and bladder) and epilepsy. They can also detect specific bacteria, such as clostridium difficile, which is found in fecal matter and is contagious.
What are the advantages of this method?
A dog detects infections within a few seconds to minutes. Other testing methods need sophisticated instruments, time, skilled workforce, and entail a significant cost.
When can a dog be considered an effective tester?
It has to be trained very well, and its capability has to be proven in trials. Dogs can be trained from three months of age. If a dog is an adult and is already trained, it needs about three to four months to get re-trained for a particular smell. For instance, dogs detecting narcotics need some additional specialised training to detect Covid infection.
Where can they be used?
Any area – like schools, colleges, public spaces, or hamlets. After detection by them, advanced testing methods can be used for confirmation.
What are the body fluids required for testing?
Saliva, urine, sweat, and, in some cases, exhaled air. For instance, Finland uses dogs in airports. Passengers are given tissue papers to take sweat or saliva samples, which would then be taken in bio-safe containers and kept in a room. Later, trained dogs are allowed to sniff the samples; Results are out in minutes.
What is the accuracy rate?
For infections, the lowest rate is 90-91 per cent. The highest level is 99.99 per cent. Advanced machines too have the same rate. For Covid, there are no studies available in public domains. Perhaps, it needs more time. Right now, priority is to save lives, especially at an affordable cost. Dogs will sniff at zero cost.
Which breeds are ideal for this purpose?
Labradors are the frontliners. Doberman, German Shepherds, Belgian Malinois, Beagle, Border Collie, Golden Retrievers, and Cocker Spaniels are commonly used.
Aren’t dogs prone to infection during sniffing?
Till date, no documented incidents exist. They are not exposed to fluids directly. A tiny hole on the container with the sample allows the dogs to sniff. There will be another two layers of protection. So far, there are no scientific report available in the public domains about Covid screening dogs getting infected. Having said that, we need necessary bio-safe infrastructure.
Can our governments use this testing model?
We can do that. But, it requires the cooperation of three entities: medical institutions, police, and veterinary medical research centres. We also need some funds.
Which countries use such a method?
Many. France, Italy, Finland, and the United States, to name a few. Not only the governments but there are private agencies that are into developing specialised canine detectives in such countries.