PATHOLOGY

Detailed explanation-1: -Flu is a contagious respiratory illness caused by influenza viruses that infect the nose, throat, and sometimes the lungs.

Detailed explanation-2: -From Latin influentia, “to flow into”; in medieval times, intangible fluid given off by stars was believed to affect humans. The Italian influenza referred to any disease outbreak thought to be influenced by stars.

Detailed explanation-3: -The flu (also called influenza) is a common illness caused by a virus. Other viruses and some bacteria can cause infections with similar symptoms, but the flu is always viral. Getting a vaccine (if available) is the best way to prevent any infection.