New Delhi, May 19 -- Health officials believe the Ebola outbreak in Congo began weeks ago.

The outbreak has been declared a public health emergency of international concern by the World Health Organization and the death toll has risen to more than 100. Two cases, including one death, have also been reported in neighboring Uganda.

Here's a timeline of what we know so far after authorities first struggled to identify the outbreak because it was caused by a rarer virus not normally associated with Ebola outbreaks in Congo:

April 24-27

A health worker who was the first suspected case authorities knew about falls ill and dies in Bunia, the capital of Ituri Province in northeastern Congo. The person's body is later transported to the nearby...