Flu viruses on nasal lining, illustration - stock illustration

Illustration of influenza (flu) virus particles in the cilia of the epithelial lining of the nasal cavity. These microscopic hair-like structures are covered with a sticky mucus (not seen) that traps dust and other inhaled particles such as as viruses. Co-ordinated, wave-like beating of the cilia propels the mucus to the back of the nose (pharynx), where it is swallowed