While speaking before a World Bank forum on the Ebola crisis, CDC Director Thomas Frieden declared that the virus is the worst since AIDS. “I would say that in the 30 years I’ve been working in public health, the only thing like this has been AIDS.” He also argued that because of its potential, the world needs to work fast to stop it. So far, the outbreak has killed more than 3,860 people, including 200 health workers. Meanwhile, officials say the condition of the Spanish nurse who contracted Ebola from a patient has deteriorated. The two doctors who treated her have been admitted for observation, bring the total number of people under quarantine at the Madrid hospital to six.