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Hookworm Causes and Risks:
The disorder is caused by infestation with the roundworms Necator
americanus, Ancylostoma duodenale, Ancylostoma ceylenicum, or Ancylostoma
braziliense. The first two occur in humans only; the last two types also occur in animals.
Hookworm disease is widespread in the moist tropics and subtropics and affects 700 million people worldwide. In developing nations, the disease indirectly causes the death of many children by increasing their susceptibility to other infections that could normally be tolerated. There is very little risk of contracting the disease in the U.S. because of advances in sanitation and control of wastes. Hookworm infection in the U.S. is most probable in the southeast.
The larvae (immature form of the worm) penetrate the skin, where an itchy rash called ground itch may develop. They migrate to lungs via the bloodstream. They then enter the airways where, as they make their way up the bronchi, they cause coughing . After traveling up the bronchi, the larva are swallowed. When the larvae are swallowed, they infect the small intestine and develop into adult worms. Adult worms and larvae are excreted in the feces.
Most people have no symptoms once the worms enter the intestines. However, iron deficiency anemia caused by loss of blood may result from heavy infestation.
Prevention:
Improvement in sanitation measures in developing countries is necessary for prevention of infection.
Symptoms:
Note : There are usually no symptoms.
Signs and Tests:
A stool ova and parasites exam will demonstrate the infection.
This disease may also alter the results of a D-xylose absorption test.
Treatment:
The objective of treatment is to cure the infestation, to treat complications of anemia , and to improve nutrition. Parasite-killing (anthelmintic or "deworming") medications are usually prescribed. Symptoms and complications of anemia are treated as they arise. There is often a recommendation made to increase the amount of protein in diet to improve nutrition.
Prognosis:
Complete recovery occurs if treatment is given before serious complications develop. The infection is easily eradicated with treatment.
Complications:
Call Your Healthcare Provider:
Call for an appointment with your health care provider if symptoms of hookworm infection develop.
This photograph shows the front section of the hookworm, and the mouth parts which it uses to feed. The chitinous plates, used to attach to the lining of the intestine where they suck blood for nourishment, are visible. Three species of hookworm cause infection in the United States, including this species, Necator americanus. (Courtesy of the Centers for Disease Control.)
This is the mouth part of the hookworm Ancyclostoma duodenale. The hookworm uses curved sharp teeth to attach to the lining of the intestine where it sucks blood for nourishment. (Courtesy of the Centers for Disease Control.)
This is a photograph of the hookworm's appearance against the lining of the intestine (intestinal mucosa). (Courtesy of the Centers for Disease Control.)
This is a photomicrograph of a hookworm egg. Hookworms hatch in damp vegetation. Their larvae can enter through the skin, even without cuts or abrasions. Once through the skin they begin the next step of their life cycle.
The larva of a hookworm is visible in the center of this photograph.
Hookworm larvae live in damp grass and vegetation and enter the body through the skin. In most cases, they only cause severe itching and redness. In this photograph, larvae have caused significant tissue damage at the site of entrance. This photograph represents an extreme case. (Courtesy of the Centers for Disease Control.)
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