The cholera epidemic is one historical event.  The disease killed at least 51 people and hospitalized hundreds and hundreds of others.  The lives of the Shona are given accurate treatment, in the ways that they engage spiritually,  socialize and live in general.  Lastly, deaths of people by wild animals are not unheard of and actually happen with a fair amount of regularity Nhamo's (whose name means "disaster," btw) was killed by a leopard when she was an infant.  In all, Farmer tries diligently to recreate a historically and culturally correct record of one girl's life in Africa. 

What are the three most important events in "A Girl Named Disaster"?

It's difficult to narrow this story down to just three important events, but I can try. The first one would have to be when Nhamo decides to look for her father's family because it is law that Nhamo belongs to her father's family, not with her mother's family. This is a way that Nhamo and her grandmother use to get Nhamo out of an unwanted marriage also. The next event would be when goes to Efifi and becomes a part of the community, earning the respect and affection of the scientists there. Efifi becomes home to Nhamo. The last event would have to be when Dr. Masuku makes Nhamo look into a mirror at the end of the book. Nhamo had refused to look at herself for many years because the last time she did, she thought she looked like "a wall spider with a burr stuck to its head." When Dr. Masuku has her look, she sees herself totally transformed.

She was taller and had a womanly figure. Her hair shone with good health, and her eyes no longer stared back from hollows. She wore a flowered dress and pink plastic shoes. The almost-emeralds glittered in her ears. She was beautiful.