How does hookworm infection lead to iron-deficiency anemia, and what stool finding is typical?

• A. Attachment to gut mucosa causing chronic blood loss; eggs in stool
• B. Production of hemolysins causing anemia; fruit in stool
• C. Impaired iron absorption from meals; no stool eggs
• D. Increased red cell destruction in the liver; mucus in stool

Answer: (B)

Hookworms cause iron-deficiency anemia mainly through chronic blood loss. These parasites attach to the lining of the small intestine and feed on blood, leading to ongoing, often occult (hidden) bleeding. Over time, the loss of iron-rich blood depletes the body's iron stores, producing iron-deficiency anemia. The typical stool finding is eggs laid by the worms, which appear in the feces on microscopic examination.

Other ideas don’t fit the biology: producing toxins that lyse red cells isn’t the mechanism hookworms use to cause anemia, and seeing nothing in the stool or finding other substances (like fruit or mucus) isn’t consistent with how hookworms are diagnosed. Iron deficiency here comes from blood loss, not from a failure of iron absorption alone.