Brendalee Flint did everything she could to keep her baby safe. She nourished her with breast milk; she gave her all the routine vaccines. But Flint never realized how much her daughter's health would depend on the actions of her friends, neighbors and even strangers.

By 15 months old, Flint's daughter, Julieanna Metcalf, was walking, exploring and even saying her first few words. Then one day in the bath, while fighting what seemed like an ordinary stomach bug, Julieanna became so weak and floppy that she couldn't hold up her head.