The World Health Organization declared a Public Health Emergency of International Concern on Sunday in response to an Ebola outbreak in the Democratic Republic of the Congo, signaling serious pandemic risk.

A rare strain of Ebola (Bundibugyo virus) is spreading in the Democratic Republic of Congo and Uganda, with more than 130 confirmed deaths and around 500 suspected cases. The World Health Organization has declared this a Public Health Emergency of International Concern. Unlike previous outbreaks, this strain has no approved vaccine or specific treatment, and experts warn the epidemic appears to be spreading out of control amid armed conflict and population displacement in the Ituri region.