In Argentina, Brazil, Chile, Colombia and Mexico, among other countries, they are training dogs so that they can detect the disease in asymptomatic patients
Does covid-19 have an odor?
That’s an answer that only a dog could accurately give us.
The olfactory capacity of one of our favorite pets has become another tool to combat the covid-19 pandemic, which has already caused more than 20 million infections and a million deaths worldwide.
In countries like Finland, Lebanon, Argentina, Chile, Germany, USA, Colombia and Mexico, the authorities are training dogs so that they can detect if people are infected with the new coronavirus.
For a few weeks, for example, specially trained dogs To identify covid-19 through smell, they began to track passengers as part of a pilot program at the Helsinki-Vantaa airport in Finland.
According to Professor Anna Hielm-Bjorkman, from the University of Helsinki, dogs can detect the virus in humans five days before symptoms develop.
“They are very good [para detectar el coronavirus]. We are approaching 100% effectiveness, ”he explains.
For his part, Felipe Valencia, a Colombian veterinarian and expert in dog training who is carrying out a similar project in conjunction with the University of Antioquia in that country, notes that the ability of the dogs could make them very reliable in these cases.
“Dogs use 40% of their brain to process what they smell, so they can become an excellent tool to combat this disease, “he says.
The idea of most of these programs is to use dogs in places of access to countries, such as airports or train stations, in order to facilitate the movement of people without the need to impose restrictions or confinements.
But how can dogs detect covid-19?
Sweat and tears
According to various research, it is difficult to establish what it is that dogs really smell.
As noted by Dr. Susan Hazel, a veterinarian at the University of Adelaide in Australia, in her article “These dogs are trained to sniff out the coronavirus,” what dogs smell are sweat samples from people, which may or may not be infected.
“The volatile organic compounds (VOCs) that are released from sweat samples are a complex mix. So it is likely that the dogs are detecting a particular profile rather than individual compounds, “says the veterinarian.
Dogs, he adds, have an average of 220 million olfactory receptors in the nose, which allows them to detect minimal alterations in substances.
The premise is the same as that used by the Chilean team of experts, another of the countries that is training dogs to detect covid-19 in asymptomatic people.
“It is not that the virus has a particular smell, but that the reaction that a person makes to the infection is what is detected,” he told the Diario.es portal. the veterinarian Fernando Madrones, from the Catholic University of Chile.
According to Madrones, when someone is infected with covid-19, it generates a series of metabolic and organic reactions, which in turn produce these VOCs, which are concentrated in the organs linked to sweat.
Even several days before the person shows any symptoms.
Samples of urine, saliva and sweat have been used in experiments around the world.
This is not the first time that dogs have been used in the detection of diseases. This procedure is known to be used in diseases such as diabetes, breast cancer, and Parkinson disease.
Even, as Professor John Logan of the London School of Hygiene and Tropical Medicine points out, in the case of malaria, dogs and their smell have “superior effectiveness to World Health Organization tests“.
But how are dogs trained to detect the “smell” of covid-19?
There are different methods, but most of the workouts are based on the strategy of reward and skip.
“Although many of the dogs we work with already have a training baseThey must first learn to recognize the virus ”, Valencia tells BBC Mundo.
Valencia points out that they are given samples, in this case of saliva from infected people, next to food or an object with which they usually train.
“Then the food or the object is taken away and only the positive test is left.“Says Valencia.
“The next process is to alternate those samples with others that do not contain the virus. When they recognize the one that contains the positive sample, they are given a prize ”, indicates the trainer.
And when they test positive to a sample that does not have COVID-19, the behavior is omitted and they are encouraged to go in search of that characteristic smell of the virus that for humans is not distinguishable.
However, Valencia makes it clear that the effectiveness of the procedure depends a lot on the training that is done with the dogs.
“We have been in this process for more than six months. And I think that in order to reach a reliable level of effectiveness, you should work with the dogs for at least four months ”, he notes.
But, ¿they can the dogs get to be infected?
“No, there really isn’t a possibility that they could get infected because the samples are protected by a material that prevents contact with the animal. In addition, we do regular tests to know their state of health, “he says.
In the Finnish case, dogs are already at the airport sniffing people entering the country, while the other countries are in the training phase with the idea that the method is “100% reliable.”
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