Measles outbreak sparks fear of resurgent diseases

Recent outbreaks of measles on both the East and West Coasts highlight a larger story about how infectious diseases that had all but disappeared in the U.S. are now reappearing. Why are some of these diseases showing back up? Hari Sreenivasan speaks with Stephen Morse, a professor of epidemiology at the Mailman School of Public Health at Columbia University, about the reasons for these outbreaks.