The winter flu season features two types of influenza. Here's what you need to know about them and how they differ.

It's flu season right now, and the U.S. is in the midst of a wave that's straining hospitals. But not all influenza is the same.

Experts say this is the worst flu season in the U.S. in more than a decade and cases are still trending up. Flu infections ...

Public health officials are closely monitoring the latest bird flu outbreak that has sickened or killed millions of birds, chicken and cattle in the U.S. The virus, also known as avian influenza ...

A cold begins when a virus attaches to the lining of your nose ... Bird flu, or avian influenza, is a viral infection spread from bird to bird. The most common kind is the H5N1 strain.