Closing schools once a student falls ill with swine flu may no longer be worth the toll on students and families, because the illness will soon be present almost everywhere in the country and few cases have been severe, said representatives from the Centers for Disease Control and Prevention. The new advice is part of a gradual easing of concerns over swine flu. While the disease has continued to spread across the and around the world, it is far less deadly than initially feared. And in Mexico, where the outbreak apparently had its origins, new cases have begun to ebb.