Coughing and scratching of the throat - these two symptoms are now well known for an infection with the novel corona virus. But apparently there is one thing that occurs even earlier and can be a first sign of Covid-19 disease: the loss of the sense of smell and taste, even if the disease is otherwise mild. Many patients notice this limitation before any other symptoms appear. In combination with other symptoms, people with loss of smell and taste appear to be three times more likely to be ill and should therefore isolate themselves for seven days to reduce the spread of the disease.
This sensory impairment is often part of the course of a cold. But the difference is that in such infections the damage to the olfactory cells is only added by the consequences of the disease. In order to taste food and drink, one needs the sense of taste, but also the sense of smell. Smell molecules from food enter the nose, the olfactory cells absorb them and transmit them to the brain. Flavoring substances in food are therefore not tasted but smelled. As soon as the nose is blocked, the aromas can no longer be transmitted and the food tastes bland. However, corona virus-infected people often do not have a stuffy nose, so there must be other causes for Covid-19. The corona virus multiplies in the upper respiratory tract, which is where the highest viral load is found and where the viruses damage their environment at an early stage. The virus docks directly to the olfactory nerves, paralysing them
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