Public health officials say they're investigating cases of severe liver disease "of unknown origin" among children in Canada as global scientists race to understand a mysterious hepatitis outbreak that has affected nearly 200 youths around the world. The latest available data from the World Health Organization shows at least 169 cases of acute hepatitis of unknown origin have been reported in close to a dozen countries, with the bulk of the reports — 114 — from the U.K. (CBC News)