Prescreening is done on a passenger arriving from Sierra Leone at O’Hare International Airport in Chicago

U.S. Coast Guard Health Technician Nathan Wallenmeyer (L) and Customs Border Protection Supervisor Sam Ko conduct prescreening measures on a passenger arriving from Sierra Leone at O’Hare International Airport’s Terminal 5 in Chicago, October 16, 2014. REUTERS/U.S. Customs Border Protection/Melissa Maraj