Aid is desperately scarce here in Bunia, the epicenter of an alarming Ebola outbreak in the Democratic Republic of Congo. Hospitals are swamped with patients infected with a rare species of the virus.

So medical staff at one hospital on the edge of the city were relieved when an international aid group erected an isolation ward in its garden, to treat the worst cases.

That respite turned to chaos on Thursday when a furious crowd stormed the hospital, hoping to retrieve the body of a suspected Ebola victim, and the isolation ward was burned to the ground.

The melee encapsulated some of the hardest challenges facing medical workers in Ituri, the province in northeastern Congo at the heart of the current outbreak.

Already, the rare Bundibugyo Ebola species has two advantages over aid workers trying to push it back: It has no vaccine or therapies, and the outbreak was detected disastrously late, perhaps two months after the first infection, health experts say.