American Museum of Natural History
American Museum of Natural History: How Lou Got the Flu
Illustrated storybook description of how the influenza virus spreads from animals to humans.
Centers for Disease Control and Prevention
Centers for Disease Control: Influenza: The Disease
Find a list of "flu-like symptoms," learn who is at risk for developing the flu, and read about how the flu is spread. This website also provides a chart showing "peak months for flu activity" and advice for treating the flu and flu...