The United States restricted entry of people who have been to three African countries, after the World Health Organization declared a global health emergency. The outbreak has killed more than 100.

This outbreak is being called "the perfect storm." How did it start, what are the characteristics of the strain that's causing it and how much of a threat is it to global health?

As Ebola cases mount in the Democratic Republic of the Congo, experts explain what causes the disease—and the risk this outbreak poses to the rest of the world.

Ebola was first identified in 1976 and since then, more than 30 outbreaks have been recorded, mostly in Central and West Africa. Some remained small and localised, while others turned into major public health crises.

The sheer number of cases and deaths are a sign that the outbreak might have been smoldering before the virus was identified.

I don’t want to lose my children.” On May 17th the World Health Organisation (WHO) said the outbreak was a “public health emergency of international concern”, only the ninth such declaration since 2005.

The World Health Organization has declared the Ebola outbreak in Congo and Uganda a public health emergency of international concern.

The health agency says the Ebola outbreak tied to the rare Bundibugyo strain is likely far larger than confirmed case counts show.