In this edition of VaccineSmarts by Richard Rupp and Bridget Hawkins: There are probably several reasons why we are hearing a lot more about so-called “new and emerging diseases.” One reason is that a slew of advances in science and technology make the identification and tracking of diseases much easier. These illnesses would have likely remained unexplained or have gone unrecognized in the past. Another reason is that our world is changing. Seven billion people inhabit the globe. Many live in crowded conditions that accelerate the spread of disease. Modern transportation enables diseases to rapidly jump from continent to continent regardless of natural barriers. Expanding cities and towns encroach on natural habitats placing humans in close contact with wildlife that may harbor disease-causing germs. Additionally, shifts in climate allow these germs to thrive in regions where they could not before.