参考答案：

Etiology（G.E）①Insufficient stores of iron；preterm low birthweight, twins, perinatal blood loss, and severe maternal ion deficiency anemia. （B分）②Inadequate dietary iron is the primary cause （B分）③rapid growth and development of infantWith the rapid growth and development of infant, blood volume increase significantly with increased body weight. Feeding the infants with foods not supplemented with iron can result in ion deficiency anemia. （B分） ④Iron absorption disturbance Unreasonable match of foods affect iron absorption and chronic diarrhea increase iron excretion. （A.E分）⑤Excessive iron lossCow milk allergy, intestinal polyp, hookworm infection, and Meckel’s diverticulum can lead to chronic blood loss. （A.E分）Treatment：（G.E分）A.General treatment: （A.E分） including nursing, prevention of infection, and rest.B.causative therapy: （B分）reasonable diet, removal of the hookworms with anthelmintic drug.C.Iron preparation treatment（B分）Oral iron preparation：elemental iron C-Fmg/kd/d in three divided doses, administered between meals. Iron medication should be continued for H wk after blood values are normal.D.Blood transfusion （B分）Blood transfusion is indicated only when the anemia is very severe or complicated with infection. Packed RBC should be given slowly in a small amount.