Sheik Umar Khan, head doctor fighting the deadly tropical virus Ebola in Sierra Leone. Sheik Umar Khan, the doctor who was leading Sierra Leone’s battle against the worst Ebola outbreak on record, has died from the virus. The West African country’s chief medical officer Brima Kargbo said the 39-year-old Khan passed away on Tuesday. Khan, who treated over 100 patients, died after dozens of local...