Frontline health workers are issuing a 24-hour strike notice that threatens to slow Ebola response operations while trials of MBP134 and remdesivir continue in Bunia.Health authorities report 1,561 confirmed cases and at least 506 deaths, with 628 patients isolated or hospitalized and 253 recovered, and cases tied to the outbreak have appeared in Uganda and France.The World Health Organization has declared the outbreak a public health emergency of international concern and warns spread remains likely as responders confront violence, community mistrust and strained treatment capacity.