The Ebo­la out­break in east­ern Con­go “con­tin­ues to out­pace the re­sponse ef­forts,” the World Health Or­ga­ni­za­tion’s emer­gen­cies chief said on Tues­day af­ter re­turn­ing from a trip to Bunia, in Ituri province, which is one of the worst hit ar­eas.

“Per­haps the most alarm­ing find­ing is that many of the new­ly re­port­ed deaths are peo­ple who died in their com­mu­ni­ties with­out ever reach­ing a health fa­cil­i­ty and with­out re­ceiv­ing care,” Chik­we Ihek­weazu said. “And as of to­day, 80% of new cas­es are out­side our con­tact lists and so are com­ing to us from un­known chains of trans­mis­sion.”

Con­go has been bat­tling the out­break of a rare type of Ebo­la since May with no ap­proved treat­ment or vac­cine. The Africa Cen­tre for Dis­ease Con­trol said last week that it is the fastest-grow­ing Ebo­la out­break on the con­ti­nent.