The U.N. health agency on Monday appealed for contributions to combat the deadly Ebola disease in West Africa, saying hundreds of doctors, nurses, health staff, and materials are needed in the region "as fast as possible." World Health Organization (WHO) spokesman Gregory Hartl said an emergency response will be implemented this week after being agreed to by the chief of the agency and the presidents of the three most affected countries—Liberia, Guinea, and Sierra Leone. WHO Secretary-General Margaret Chan and the three West African leaders agreed on an Ebola disease response plan involving three co-centric rings in the most-affected areas along their common border, Hartl said. "They want to institute emergency measures to encourage people to stay in those areas and not leave, in order not to spread the disease to other areas," Hartl told U.N. Radio, and to do that, they will increase supplies of food and other benefits into the areas so that people can stay there. As a result of the plan, the U.N. agency has launched a $100 million appeal. "We need many more contributions from the international community, from governments, from NGOs (non-governmental organizations), academic institutions, from anyone who can provide us with doctors, nurses, ... and other public-health staff," Hartl said.