GREENSBURG, Pa. (AP) — The nuns' daily email update was overtaken by news of infections. Ambulances blared into the driveways of their convents. Prayers for the sick went unanswered, prayers for the dead grew monotonous and, their cloistered world suddenly caving in, some of the sisters' thoughts were halting.

"How many of us," Sister Mary Jeanine Morozowich wondered, "will be left?"

These were women who held the hands of the dying and who raised the unwanted, who pushed chalk to slate to teach science and grammar and, through their own example, faith. And when the worst year was over, the tol...