The current ebola outbreak is the largest in history, with 672 dead in Guinea, Liberia, and Sierra Leone. At least two Americans have now been infected with the disease: Dr. Kent Brantly of Texas and Nancy Writebol of North Carolina, who both worked in an ebola clinic in Monrovia, Liberia. The US Centers for Disease Control and Prevention (CDC), which has been active in the ebola crisis, says there is no established protocol for evacuating American aid workers. Whether an American citizen would be transported to another country would be determined on a case by case basis, and it’s something we’re working now on figuring out now, spokesperson Kristen Nordlund tells The Verge.