Nigeria, Jan. 8 -- The wards of the Doctors Without Borders/Medecins Sans Frontieres (MSF)-supported hospital in Gummi, Nigeria, are rarely quiet during the rainy season. Mothers sit close to metal beds, watching over children experiencing fevers, convulsions, and exhaustion. Outside, the rain brings relief from the heat. But inside the hospital's walls, it brings with it a surge of complicated malaria cases that push families and health workers to their limits.

"During the rainy season, we experience the highest influx of malaria cases in our project," says Dr. Balarabe Tirmizi, an MSF doctor in Gummi. "The numbers have increased year after year. Many children arrive very late and very sick, but if they reach us in time, malaria is trea...