Nyajima weighed just 20 pounds when admitted to the hospital, which is in a camp for internally displaced people in the South Sudanese capital. A child of her age and height should have weighed closer to 50 pounds.

Here Nyajima sits with help from her father. Her muscles were too weak to support even her tiny frame.

Still weak, and unable to hold the weight of her own head.

Doctors immediately began an intensive and carefully monitored feeding program and administered medications to fight the tuburculosis. After a few days, Nyajima was able to sit up on her own for short periods.

Now taking tentative but very weak steps with her father.

Furtive steps with her father, and giving a wave to the camera, Nyajima was getting used to seeing photographer Sebastian Rich, who visited to document her progress about every other day.

Just starting to smile, but Nyajima still needs help keeping her head up.

Smiling in bed, and sitting up all on her own, Nyajima was beginning to make rapid progress.

Being weighed by a nurse on the road to recovery.

Nyajima joins her father and doctors as they look over charts tracking her progress.

This was the day that Nyajima left the hospital, smiling and in good health with her father, only about three weeks after being admitted in a desperate condition. The doctors said she was an incredibly lucky little girl.

Before she said goodbye to photographer Sebastian Rich, Nyajima, who had regained not only her strength and her smile, but the curiosity and playfullness any 4-year-old in the world should naturally exhibit, sneakily grabbed Rich's glasses from his shirt as he shot other subjects. Placing them on her own face, she smiled at him and demanded one last picture. Rich couldn't refuse.

Sebastian Rich is a freelance photographer on assignment in South Sudan and Somalia.