How does the story of what Okonkwo and Ekwefi went through a year ago display the villager’s belief in the spiritual world?

A year ago, Okagbue, the medicine man, found Ezinma's iyi-uwa, her supposed link to the world of the ogbanje. So the girl should not die again. But Ekwefi, fearful that she might lose the child that is the center of her life, is terrified. Okonkwo believes it is iba sickness, and he gathers herbs and begins to prepare a medicine for Ezinma. The girl is held over a concoction of herbs and hot water, and forced to breathe in the steam.