(Photo Credit: E+/Getty Images) Three types of flu viruses affect humans: types A, B, and C. Type A and B cause the annual influenza epidemics that have up to 20% of the population sniffling ...

A virus is a microorganism that can cause infectious diseases, such as influenza, in many different types of organism. More SciePro / dragana991/iStock / Getty Images Plus / Canva When flu season ...

Liubomyr Vorona/iStock / Getty Images Plus According to the CDC, there are two other types of flu viruses: C and D. Influenza C typically only causes mild illness and is not thought to cause human ...

The infections include Respiratory Syncytial Virus, Influenza A, better known as swine flu, and influenza B types.

The flu is a contagious viral infection of the respiratory system that affects the nose, throat and lungs. It is caused by influenza viruses. Symptoms of mild flu infections can resemble those of ...

Influenza, commonly called "the flu," is caused by viruses that infect the respiratory tract. Compared with most other respiratory infections, such as the common cold, the flu often causes a more ...