2. Cough

Coughing is also another sign a patient is coming down with the flu and is the body’s response to get rid of fluids, such as mucus and other irritants, that block the patient’s breathing passages thereby causing them to have difficulty breathing. An over production of mucus in the upper respiratory tract (which includes the nose, mouth, and throat) is what commonly triggers the cough reflex in patients, paving the way by which aerosols, tiny fluid particles, containing live viruses find their way into the air, allowing other people to be infected, thereby ensuring the survival of the virus in other hosts.