Intestinal worms- hookworms Custom Search Hookworms so called because of hook like shape of their bodies are common in tropical and subtropical countries. The common hook worms affecting man are Ancylostoma duodenale and Necator americanus. The adult worms live in upper part of small intestine. The worms get attached to the wall of the intestine and suck blood. With heavily worm load the loss of blood can be significant and lead to anemia. The eggs are passed in feces and develop into larvae in soil. The larvae penetrate the skin on contact and enter the blood stream. They reach the alveoli of lungs, are coughed up, swallowed and develop into adult worms. Symptoms and signs: The larvae cause intense itching at the site where they enter the skin. The itching may subside as the larvae move further. When they enter the lungs a transient pneumonia like illness may develop. Life cycle of hookworm
One species of hook worm called Ancylostoma braziliense which affects dogs and cats may occasionally penetrate the skin of man. It cannot complete its cycle and dies within the skin. It merely causes curved burrows in the skin. This is called cutaneous larva migrans (creeping eruption). With heavy load of worms there can be abdominal pain, diarrhea and anemia due to chronic blood loss. Laboratory findings: The ova may be demonstrated by examining the stool under the microscope. Anemia may be found. Treatment: The drugs affective are mebendezole 100mg twice daily for 3 days and pyrantel pamoate 11mg/kg per day for 3 days. It is important to treat anemia with iron. Prevention: Proper disposal of human excrete and avoidance of contact with contaminated soil help prevent the problem. Strongyloides stercoralis (threadworms)Strongyloides stercoralis also called as threadworm is another common intestinal worm in tropical and sub tropical countries. The adult worms live in the small intestine. The eggs laid by the adult worms quickly hatch within the intestine itself and develop into first stage larvae (also called as rhabditiform larvae). Hence examination of stool usually shows the larvae and not eggs. Some of these larvae develop into filariform larvae which can penetrate the tissues causing auto-infection. Those larvae excreted along with the feces survive in soil for sometime and can penetrate the skin of other people, enter blood stream, reach alveoli of lungs, get coughed up and swallowed. These develop into adults. Life cycle of threadworm. Click on the graphic to visit the CDC website for more graphics
Symptoms and signs: Al the site of skin penetration there will be itching and rash. When the larvae reach the lungs cough and wheezing occur. Sometimes the damage to the lungs can cause some bleeding resulting in coughing up of blood (hemoptysis). Worms in intestine can lead to abdominal pain, nausea, vomiting, diarrhea and malabsorption. Laboratory findings: The larvae can be found in stool or duodenal aspirate. Occasionally the larvae may be found is sputum. Specific antibody test is also available. Treatment: Thiabendazole 25mg per kg 2 times daily for 2 days and Ivermectin 200mg per kg per day for 2 days are effective. Custom Search
Page last reviewed on 10th October 2010
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