Hookworm
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Definition
Hookworm is a condition caused by roundworms that affects the small intestine and lungs.
Causes, incidence, and risk factors
The disorder is caused by infestation with the roundworms:
Necator americanus
Ancylostoma duodenale
Ancylostoma ceylanicum
Ancylostoma braziliense
The first two roundworms affect humans only. The last two types also occur in animals.
Hookworm disease is common in the moist tropics and subtropics. It affects about 1 billion people worldwide. In developing nations, the disease leads to the death of many children by increasing their risk for infections that their bodies would normally fight off.
There is very little risk of getting the disease in the United States because of advances in sanitation and waste control. The important factor in getting the disease is walking where people who have hookworm have made feces.
The larvae (immature form of the worm) get into the skin. The larvae move to the lungs via the bloodstream and enter the airways. The worms are about 1/2 inch long.
After traveling up the windpipe, the larva are swallowed. After the larvae are swallowed, they infect the small intestine. They develop into adult worms and live there for 1 or more years. Adult worms and larvae are released in the feces.
References
Kazura JW. Nematode infections. In: Goldman L, Ausiello D, eds. Cecil Medicine. 23rd ed. Philadelphia, Pa: Saunders Elsevier; 2007:chap 378.
Maguire JH. Intestinal nematodes (roundworms). In: Mandell GL, Bennett JE, Dolin R, eds. Principles and Practice of Infectious Disease. 7th ed. Philadelphia, Pa: Elsevier Churchill Livingstone; 2009:chap 287.
Review Date: 8/24/2011
Reviewed By: David C. Dugdale, III, MD, Professor of Medicine, Division of General Medicine, Department of Medicine, University of Washington School of Medicine; and Jatin M. Vyas, PHD, MD, Instructor in Medicine, Harvard Medical School, Assistant in Medicine, Division of Infectious Disease, Massachusetts General Hospital. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M., Inc.
The information provided herein should not be used during any medical emergency or for the diagnosis or treatment of any medical condition. A licensed physician should be consulted for diagnosis and treatment of any and all medical conditions. Call 911 for all medical emergencies. Links to other sites are provided for information only -- they do not constitute endorsements of those other sites. Copyright 2004 A.D.A.M., Inc. Any duplication or distribution of the information contained herein is strictly prohibited.
Symptoms
Most people have no symptoms once the worms enter the intestines.
Signs and tests
Tests that can help diagnose the infection include:
This disease may also affect the results of a D-xylose absorption test.
References
Kazura JW. Nematode infections. In: Goldman L, Ausiello D, eds. Cecil Medicine. 23rd ed. Philadelphia, Pa: Saunders Elsevier; 2007:chap 378.
Maguire JH. Intestinal nematodes (roundworms). In: Mandell GL, Bennett JE, Dolin R, eds. Principles and Practice of Infectious Disease. 7th ed. Philadelphia, Pa: Elsevier Churchill Livingstone; 2009:chap 287.
Review Date: 8/24/2011
Reviewed By: David C. Dugdale, III, MD, Professor of Medicine, Division of General Medicine, Department of Medicine, University of Washington School of Medicine; and Jatin M. Vyas, PHD, MD, Instructor in Medicine, Harvard Medical School, Assistant in Medicine, Division of Infectious Disease, Massachusetts General Hospital. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M., Inc.
The information provided herein should not be used during any medical emergency or for the diagnosis or treatment of any medical condition. A licensed physician should be consulted for diagnosis and treatment of any and all medical conditions. Call 911 for all medical emergencies. Links to other sites are provided for information only -- they do not constitute endorsements of those other sites. Copyright 2004 A.D.A.M., Inc. Any duplication or distribution of the information contained herein is strictly prohibited.
Treatment
The goals of treatment are to:
- Cure the infection
- Treat complications of anemia
- Improve nutrition
Parasite-killing medications such as albendazole, mebendazole, or pyrantel pamoate are usually prescribed. Ivermectin, used for other worm infections, does not work for hookworm infections.
Symptoms and complications of anemia are treated as they arise. The doctor will likely recommend increasing the amount of protein in your diet.
Expectations (prognosis)
You will have a complete recovery if you get treated before serious complications develop. Treatment gets rid of the infection.
Complications
Calling your health care provider
Call for an appointment with your health care provider if symptoms of hookworm infection develop.
References
Kazura JW. Nematode infections. In: Goldman L, Ausiello D, eds. Cecil Medicine. 23rd ed. Philadelphia, Pa: Saunders Elsevier; 2007:chap 378.
Maguire JH. Intestinal nematodes (roundworms). In: Mandell GL, Bennett JE, Dolin R, eds. Principles and Practice of Infectious Disease. 7th ed. Philadelphia, Pa: Elsevier Churchill Livingstone; 2009:chap 287.
Review Date: 8/24/2011
Reviewed By: David C. Dugdale, III, MD, Professor of Medicine, Division of General Medicine, Department of Medicine, University of Washington School of Medicine; and Jatin M. Vyas, PHD, MD, Instructor in Medicine, Harvard Medical School, Assistant in Medicine, Division of Infectious Disease, Massachusetts General Hospital. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M., Inc.
The information provided herein should not be used during any medical emergency or for the diagnosis or treatment of any medical condition. A licensed physician should be consulted for diagnosis and treatment of any and all medical conditions. Call 911 for all medical emergencies. Links to other sites are provided for information only -- they do not constitute endorsements of those other sites. Copyright 2004 A.D.A.M., Inc. Any duplication or distribution of the information contained herein is strictly prohibited.
Prevention
Developing countries need to improve sanitation measures to prevent infection.
References
Kazura JW. Nematode infections. In: Goldman L, Ausiello D, eds. Cecil Medicine. 23rd ed. Philadelphia, Pa: Saunders Elsevier; 2007:chap 378.
Maguire JH. Intestinal nematodes (roundworms). In: Mandell GL, Bennett JE, Dolin R, eds. Principles and Practice of Infectious Disease. 7th ed. Philadelphia, Pa: Elsevier Churchill Livingstone; 2009:chap 287.
Review Date: 8/24/2011
Reviewed By: David C. Dugdale, III, MD, Professor of Medicine, Division of General Medicine, Department of Medicine, University of Washington School of Medicine; and Jatin M. Vyas, PHD, MD, Instructor in Medicine, Harvard Medical School, Assistant in Medicine, Division of Infectious Disease, Massachusetts General Hospital. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M., Inc.
The information provided herein should not be used during any medical emergency or for the diagnosis or treatment of any medical condition. A licensed physician should be consulted for diagnosis and treatment of any and all medical conditions. Call 911 for all medical emergencies. Links to other sites are provided for information only -- they do not constitute endorsements of those other sites. Copyright 2004 A.D.A.M., Inc. Any duplication or distribution of the information contained herein is strictly prohibited.
Review Date: 8/24/2011
Reviewed By: David C. Dugdale, III, MD, Professor of Medicine, Division of General Medicine, Department of Medicine, University of Washington School of Medicine; and Jatin M. Vyas, PHD, MD, Instructor in Medicine, Harvard Medical School, Assistant in Medicine, Division of Infectious Disease, Massachusetts General Hospital. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M., Inc.
The information provided herein should not be used during any medical emergency or for the diagnosis or treatment of any medical condition. A licensed physician should be consulted for diagnosis and treatment of any and all medical conditions. Call 911 for all medical emergencies. Links to other sites are provided for information only -- they do not constitute endorsements of those other sites. Copyright 2004 A.D.A.M., Inc. Any duplication or distribution of the information contained herein is strictly prohibited.