David M. MorensGregory K. FolkersAnthony S. FauciBethesda, MD, USA This article was first published in Lancet Infectious Diseases, Volume 8, Issue 11, Nov. 2008, pages 710–719 and has been formatted for Hektoen International. Summary Emerging and re-emerging infectious diseases, and their determinants, have recently attracted substantial scientific and popular attention. HIV/AIDS, severe acute respiratory syndrome,…