The head of the World Health Organization on Monday concluded his visit to Democratic Republic of Congo by briefing the president on the response to the Ebola outbreak, which an aid agency warned was likely much larger than official figures show. The outbreak, already the third-largest on record, persisted for weeks undetected, say health officials, who are now behind the curve and ‌struggling to bring it under control. Arriving in DR Congo last week, WHO Director General Tedros Adhanom...