In esperanza rising what is mamas sickness?

In "Esperanza Rising," Mama suffers from a mysterious illness, which is later revealed to be a severe case of valley fever, a fungal infection. This illness significantly impacts Esperanza and her family's circumstances, as they must navigate the challenges of their new life in America while dealing with Mama's health issues. Her sickness serves as a catalyst for Esperanza's growth and resilience throughout the story.