According to various studies, being smokers increases the risk of contracting the flu, compared to non-smokers. But the risks do not stop there since, according to a Swiss team, cigarettes worsen flu symptoms. And this notably through the intestinal microbiota!
Researchers from the University of Bern have in fact demonstrated that chronic exposure to smoke significantly alters the microbial communities present in the intestine and the oropharynx (region bringing together the soft palate, the walls of the throat, the tonsils and the back of the tongue) in mice.
To reach this conclusion, the scientists used an innovative approach: transferring the microbiota from mice exposed to cigarette smoke to axenic mice, that is, completely devoid of microbes. The latter were then infected with the influenza A virus.
The results are telling: the mice that received the infected microbiota developed more severe symptoms, characterized in particular by greater weight loss. Viral infection also led to changes in the composition of the oropharyngeal microbiota, particularly one week after infection.
« It is not just smoking itself that impacts respiratory diseases », Explains Professor Markus Hilty, lead author of the study. “ Our data suggest that cigarette-induced disruption of the microbiota also plays an important role in the development and severity of respiratory infections. »
A discovery that opens new perspectives in understanding the mechanisms by which smoking increases vulnerability to respiratory infections. It also underlines the importance of considering disturbances in the microbiota as a risk factor for complications of influenza.
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