US Centers for Disease Control and Prevention (CDC) Director Tom Frieden shows an awareness poster as he testifies before Africa, Global Health, Global Human Rights and International Organizations Subcommittee hearing on 'Combating the Ebola Threat' at the Rayburn House Office Building in Washington, DC, on August 7, 2014. Overwhelmed west African nations called states of emergency on Thursday as the death toll from a fast-spreading Ebola epidemic neared 1,000. AFP PHOTO/Jewel Samad        (Photo credit should read JEWEL SAMAD/AFP/Getty Images)