(VOX) – At least 680 people have been infected with the Ebola virus in the Democratic Republic of Congo. It’s the second-largest Ebola outbreak in history, with 414 deaths so far, and the first Ebola outbreak in an active war zone, DRC’s eastern North Kivu and Ituri provinces. But it could get worse: Health officials this week are concerned that Ebola appears to be spreading in the direction of Goma, a major population center in DRC.

Just this week, DRC’s health ministry confirmed four cases of the deadly virus in Kayina, a town in North Kivu, where fighting among rebel and militia groups has repeatedly interrupted the painstaking work of health workers who are responding to the outbreak. Kayina happens to be halfway between Butembo, currently one of the outbreak’s most worrisome hotspots, and Goma, where a million people live. READ MORE