Winter brings snow, ice, and freezing temperatures, but these climatic conditions are also the harbingers of another time of year: flu season. We all know the signs chills, fever, sore throat, muscle pains, coughing and hope that this common illness will make us sick for only a few days. But though the flu may seem harmless, influenza results in between 250,000 and 500,000 deaths every year and can spread virulently around the world. In pandemic years, the flu can kill millions.The recurrence of the Spanish Flu virus, the appearance and spread of Bird Flu, and the 2009 Swine Flu have...