The deadly spread of Ebola in West Africa is something unseen since the outbreak of AIDS, Thomas Frieden, director of the US Centers for Disease Control and Prevention, said Thursday.

"I would say that in the 30 years I've been working in public health, the only thing like this has been AIDS," he told a top-level Ebola forum in Washington.

"It's going to be a long fight," he told the heads of the United Nations, World Bank and International Monetary Fund gathered in Washington.

"We have to work now so that it is not the world's next AIDS."