Sarah wandered from bed to bed, checking on the few patients at the Hedley Clinic. It was such a welcome contrast from when she'd arrived and established the makeshift hospital off the Rio Negro. The treatment area had overflowed with patients from the first day, all in desperate need of care. Malaria, Yellow Fever, Cholera, Typhoid fever, and uncontrolled diabetes had run rampant throughout the area. But thanks to antimalarial drugs, vaccinations, antibiotics, and rehydration solutions, the number of patients had dwindled dramatically. Most days brought patients with ear infections, high blood pressure, asthma attacks, and even the occasional prenatal checkup. Still, there was a relatively regular flow of emergency patients suffering injuries from farming accidents and even alligator bites. The enormous black caimans were especially troublesome, particularly during the wet seasons when they ventured into the flooded savannas of the Amazon basin.

Though there was so much more she wished she could do, never a day went by when she didn't feel she made an...