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Hookworm infection

Hookworm disease; Ground itch;  Ancylostoma duodenale infection; Necator americanus infection; Parasitic infection - hookworm

Hookworm infection is caused by roundworms. The disease affects the small intestine and lungs.

Causes

The infection is caused by infestation with any of the following roundworms:

  • Necator americanus
  • Ancylostoma duodenale
  • Ancylostoma ceylanicum
  • Ancylostoma braziliense

The first 2 roundworms affect humans only. The last 2 types also occur in animals.

Hookworm disease is common in the moist tropics and subtropics. 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 barefoot on ground where there are feces of people who have hookworm.

The larvae (immature form of the worm) enter the skin. The larvae move to the lungs via the bloodstream and enter the airways. The worms are about one half inch (1 centimeter) long.

After traveling up the windpipe, the larvae 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. The worms attach to the intestinal wall and suck blood, which results in iron deficiency anemia and protein loss. Adult worms and larvae are released in the feces.

Symptoms

Symptoms may include:

Most people have no symptoms once the worms enter the intestines.

Exams and Tests

Tests that can help diagnose the infection include:

Treatment

The goals of treatment are to:

  • Cure the infection
  • Treat complications of anemia
  • Improve nutrition

Parasite-killing drugs such as albendazole, mebendazole, or pyrantel pamoate are often prescribed.

Symptoms and complications of anemia are treated, if needed. The health care provider will likely recommend increasing the amount of protein in your diet.

Outlook (Prognosis)

You will have a complete recovery if you get treated before serious complications develop. Treatment gets rid of the infection.

Possible Complications

Health problems that may result from hookworm infection include:

  • Iron deficiency anemia, caused by loss of blood
  • Nutritional deficiencies
  • Severe protein loss with fluid buildup in the abdomen (ascites)

When to Contact a Medical Professional

Call for an appointment with your provider if symptoms of hookworm infection develop.

Prevention

Handwashing and wearing shoes will reduce the likelihood of infection.

References

Diemert DJ. Intestinal nematode infections. In: Goldman L, Schafer AI, eds. Goldman's Cecil Medicine. 25th ed. Philadelphia, PA: Elsevier Saunders; 2016:chap 357.

Hotez PJ. Hookworms (Necator americanus and Angylostoma spp.). In: Kliegman RM, Stanton BF, St. Geme, Schor NF, eds. Nelson Textbook of Pediatrics. 20th ed. Philadelphia, PA: Elsevier; 2016:chap 292.

    • Hookworm - mouth of the organism

      Hookworm - mouth of the organism - illustration

      Necator americanus

      Hookworm - mouth of the organism

      illustration

    • Hookworm - close-up of the organism

      Hookworm - close-up of the organism - illustration

      Ancyclostoma duodenale

      Hookworm - close-up of the organism

      illustration

    • Hookworm - Ancylostoma caninum

      Hookworm - Ancylostoma caninum - illustration

      This is a photograph of a hookworm on the lining of the intestine. (Image courtesy of the Centers for Disease Control and Prevention.)

      Hookworm - Ancylostoma caninum

      illustration

    • Hookworm egg

      Hookworm egg - illustration

      This is a hookworm egg. Hookworms hatch in damp vegetation. Their larvae can enter the human body through the skin, even without cuts or abrasions. Once through the skin, they begin the next step of their life cycle.

      Hookworm egg

      illustration

    • Hookworm rhabditiform larva

      Hookworm rhabditiform larva - illustration

      The larva of a hookworm is visible in the center of this photograph.

      Hookworm rhabditiform larva

      illustration

    • Digestive system organs

      Digestive system organs - illustration

      The digestive system organs in the abdominal cavity include the liver, gallbladder, stomach, small intestine and large intestine.

      Digestive system organs

      illustration

      • Hookworm - mouth of the organism

        Hookworm - mouth of the organism - illustration

        Necator americanus

        Hookworm - mouth of the organism

        illustration

      • Hookworm - close-up of the organism

        Hookworm - close-up of the organism - illustration

        Ancyclostoma duodenale

        Hookworm - close-up of the organism

        illustration

      • Hookworm - Ancylostoma caninum

        Hookworm - Ancylostoma caninum - illustration

        This is a photograph of a hookworm on the lining of the intestine. (Image courtesy of the Centers for Disease Control and Prevention.)

        Hookworm - Ancylostoma caninum

        illustration

      • Hookworm egg

        Hookworm egg - illustration

        This is a hookworm egg. Hookworms hatch in damp vegetation. Their larvae can enter the human body through the skin, even without cuts or abrasions. Once through the skin, they begin the next step of their life cycle.

        Hookworm egg

        illustration

      • Hookworm rhabditiform larva

        Hookworm rhabditiform larva - illustration

        The larva of a hookworm is visible in the center of this photograph.

        Hookworm rhabditiform larva

        illustration

      • Digestive system organs

        Digestive system organs - illustration

        The digestive system organs in the abdominal cavity include the liver, gallbladder, stomach, small intestine and large intestine.

        Digestive system organs

        illustration

      Review Date: 9/10/2015

      Reviewed By: Jatin M. Vyas, MD, PhD, Assistant Professor in Medicine, Harvard Medical School; Assistant in Medicine, Division of Infectious Disease, Department of Medicine, Massachusetts General Hospital, Boston, MA. Also reviewed by David Zieve, MD, MHA, Isla Ogilvie, PhD, and the A.D.A.M. Editorial team.

      The information provided herein should not be used during any medical emergency or for the diagnosis or treatment of any medical condition. A licensed medical professional should be consulted for diagnosis and treatment of any and all medical conditions. Links to other sites are provided for information only -- they do not constitute endorsements of those other sites. © 1997- A.D.A.M., Inc. Any duplication or distribution of the information contained herein is strictly prohibited.
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