© 1996-2011 WGBH Educational Foundation. In a short online video, scientists contrast the ways bird flu and human flu spread. Students simulate the spread of a virus using colored stickers and develop a sense of the numbers of people affected by the 1918 flu. Students make avian and human influenza A virus models and then infect a model lung cell to make a hybrid virus that has some avian and some human RNA segments and surface proteins.
