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Additional Information From NIAID

Hookworm Disease

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Diarrhea sometimes starts as the worms mature in your intestines and before eggs appear in the stool, particularly if you have never been infected by hookworms. During this stage of the disease you may have other symptoms, such as barely noticeable abdominal pain, intestinal cramps, colic, and nausea.

Scientists have learned that people in good health and on a diet containing adequate amounts of iron can tolerate the presence of these worms in small or moderate numbers without any symptoms.

In chronic (lasting a long time) hookworm infections, if the number of parasites becomes great enough, you can develop serious anemia (low red blood cell count). This is due to blood loss from the worms attaching themselves to the intestines and sucking the blood and tissue juices. When this situation is combined with poor nutrition, pregnancy, or malaria, the anemia can be severe.

Last Updated September 13, 2007

Last Reviewed May 12, 2011