Coronavirus: Loss of smell is different from that of a cold. Research that demonstrates the differences.
Don't store avocado like this: it's dangerousIn recent months we have learned, in spite of ourselves, the symptoms of Covid-19. Fever and cough, vomiting and diarrhea, and most importantly, loss of taste and smell. A symptom, the latter, very common even in those who have a common cold.
But are there any differences between the loss of smell experienced by patients with Covid-19 and that of those who have a common cold? The nose does not run and the patient breathes well, first of all, in the case of the coronavirus.
An international research team led by scientists from the Saint-Luc University Clinics in Brussels and the Catholic University of Leuven (Belgium), who collaborated with colleagues from the Norwich Medical School at the University of East Anglia ( United Kingdom), The Norfolk Smell & Taste Clinic, the Otolaryngology Department of the Taksim Hospital in Istanbul, the University Hospital of Foggia and other research centers around the world.
The results of the research "Comparison of COVID-19 and common cold chemosensory dysfunction" have been published in the specialized scientific journal Rhinology.
A previous survey by the British Association of Otorhinolaryngology had already found that one third of people infected with the coronavirus also had a loss of smell (anosmia or hyposmia), even in the absence of other symptoms.
Researchers from Harvard Medical School's Department of Neurobiology then studied genetic data to identify the types of olfactory tissue cells that could have allowed the coronavirus to inhibit the perception of scents.
They found that olfactory sensory neurons do not express two key genes (ACE2 and TMPRSS2) that allow the coronavirus to infect cells. In contrast, olfactory tissue stem cells express both of these genes. The latter, found in the cells of the nasal respiratory tissue, are the main target and site of viral multiplication of the new coronavirus.
Why is loss of smell one of the symptoms of Covid-19? The answer from Harvard scientists
The new study
For the new research, the scientists involved a sample of 30 people (10 with Covid-19, 10 with a bad cold and 10 healthy) and subjected them to various tests to evaluate the ability to perceive odors and taste and determine the differences.
Analyzing the data, it emerged that one of the main differences between patients infected with the coronavirus and those with colds would lie in the fact that the former can breathe freely through the nose, since they have not closed or runny (rhinorrhea). In addition, those affected by Covid-19 are unable to perceive bitter and sweet tastes.
“We found that the loss of smell was much deeper in COVID-19 patients. They were less able to identify smells and were unable to detect bitter or sweet tastes. In fact, the loss of taste seemed to be the substantial difference between patients with Covid-19 compared to those with a cold, "said Professor Carl Philpott in a press release published by the University of'East Anglia.
Why such a difference? According to the scientists, it should have been the fact that SARS-CoV-2 manages to make its way into the central nervous system and inflame it, probably through the olfactory bulb,
A difference, this, of great interest, since - as the experts conclude - with special rapid tests it would be possible a priori to distinguish a patient with Covid-19 from one affected by a common respiratory disease.
Of course, as the authors of the research conclude, these tests will not be able to replace rhino-pharyngeal swabs and similar tests, but, developed in the case of a shortage of swabs and used where rapid screening is needed, could be of great help.
Font: Rhinology / UEA
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Coronavirus: the sudden loss of taste and smell among the symptoms of "healthy" patients. The English analysis
