Health Agencies Check If Ebola Virus Is Changing as Congo Outbreak Grows

Congo's Ebola outbreak has topped 4,000 infections and 1,800 deaths — the second-worst ever. Two top health agencies, Africa CDC and WHO, want to find out if the virus is changing in ways that matter. The type involved here has historically been less deadly than the one behind the 2014–18 epidemic that killed over 11,000 people.