Radiation Effects
This girl, Aiko (9), and her younger brother, Toru (7), were exposed to the bomb in a wooden building 1,000 m from the hypocenter. After that, they went outdoors and got caught in the black rain. Their hair began falling out four or five days later. Aiko lost her appetite and developed a fever, bleeding from the gums and other symptoms. Both recovered from the acute stage but fell ill in later years. Toru died 4 years after the bombing at the age of 11, and Aiko died 20 years after the bombing at the age of 29.
Source: US Army