(UNITED NATIONS) — More than half a million children in the West African area wracked by Boko Haram extremists are so malnourished their lives could be in danger unless they get aid, a U.N. humanitarian official said Monday, describing a region where millions get by on one meal a day and some communities have lost all their toddlers. Military campaigns have driven Boko Haram from much of the territory it took during a seven-year uprising that killed more than 20,000 people, displaced over 2 million and shocked the world with the abduction of nearly 300 schoolgirls.