People set fire to an Ebola treatment center in a town at the heart of the outbreak in eastern Congo as fear and anger grow over a health crisis that doctors are struggling to contain.

The outbreak has alarmed experts because it was able to spread for weeks undetected across a densely populated area ravaged by widespread armed violence.

The World Health Organization top official has expressed concern over the rapid spread of a rare type of Ebola in Congo. Authorities have reported at least 134 suspected deaths…