Learn how Type B Influenza virus has genetic drift, whereas Type A Influenza virus has genetic drift AND shift. Rishi is a pediatric infectious disease physician and works at Khan Academy. [7:44]

Learn about the three types of influenza virus (Type A, Type B, and Type C) and what makes them different from one another. Rishi is a pediatric infectious disease physician and works at Khan Academy. [8:16]

We'll get the latest on the outbreak of Type A, H1N1 influenza. What are researchers learning from studying the virus -- and how are doctors and other health professionals dealing with its spread?