The countries had until June 2012 to meet the core requirements, such as strengthening surveillance systems to detect emerging diseases. Eighty-four percent failed to do so, said Rebecca Katz of George Washington University, an expert in global health security. The reasons included lack of scientific capacity to conduct disease surveillance, such as to detect a new bird virus spreading to people, too few trained epidemiologists and the fact that "some things are just plain hard, like being able to detect and contain a disease at points of entry into a country," said Katz.