Helminthic Infections: Intestinal Nematodes
Nematodes are elongated, symmetrical roundworms. These can be classified as either intestinal
or tissue nematodes. Intestinal nematode species include nematodes, Enterobius vermicularis,
Trichuris trichuira, Ascaris lumbricoides, Necator americanus, and Ancylostoma duodenale.
Worldwide, more than 1 billion people are infected with one or more of his 4,444 species of
intestinal nematodes. They are most common in areas with poor sanitation and are especially
found in developing countries.
Ascariasis
Ascariasis is an infection caused by roundworms. Ascariasis is common worldwide, especially in
areas with poor sanitation. Children often get ascariasis from ingesting embryonated eggs.
Adults live in the lumen of the small intestine, especially in the jejunum. eggs enter the external
environment with feces. When ingested, these eggs hatch into and release tiny larvae that
quickly enter the blood vessels and lymphatics of the intestinal wall. Some larvae reach the
portal circulation and are carried to the liver. Others pass through the thoracic duct. It is filtered
from the bloodstream and reaches the lungs (lung stage). After an increase in size, they migrate
to the epiglottis and down the esophagus to reach's intestines, where mating takes place.
Clinical Features
• An unproductive cough and burning sensation, which may cause significant discomfort. Fever
is common at this stage.
• In established infections, patients are often asymptomatic.
• Serious infections, especially in children, large boluses of worms can cause pain and small
bowel obstruction, chronic abdominal discomfort, and growth retardation. Large nematodes
can enter and obstruct the biliary system, causing biliary colic, cholecystitis, and pancreatitis.
Diagnosis: Most cases of ascariasis can be diagnosed by microscopic detection of characteristic
roundworm eggs in feces.
Treatment:
Mebendazole 100 mg twice daily for 3 days
Piperazine 75 mg/kg (maximum 3.5 g) once daily for 2 days Pyrantelpamoate 10 mg/kg once
Albendazole 400 mg once is also valid.
Hookworm
An infection caused by two species of hookworms, Ancylostoma duodenale, and Necator
americanus. Worldwide distribution, however, older children have the highest incidence and
Nematodes are elongated, symmetrical roundworms. These can be classified as either intestinal
or tissue nematodes. Intestinal nematode species include nematodes, Enterobius vermicularis,
Trichuris trichuira, Ascaris lumbricoides, Necator americanus, and Ancylostoma duodenale.
Worldwide, more than 1 billion people are infected with one or more of his 4,444 species of
intestinal nematodes. They are most common in areas with poor sanitation and are especially
found in developing countries.
Ascariasis
Ascariasis is an infection caused by roundworms. Ascariasis is common worldwide, especially in
areas with poor sanitation. Children often get ascariasis from ingesting embryonated eggs.
Adults live in the lumen of the small intestine, especially in the jejunum. eggs enter the external
environment with feces. When ingested, these eggs hatch into and release tiny larvae that
quickly enter the blood vessels and lymphatics of the intestinal wall. Some larvae reach the
portal circulation and are carried to the liver. Others pass through the thoracic duct. It is filtered
from the bloodstream and reaches the lungs (lung stage). After an increase in size, they migrate
to the epiglottis and down the esophagus to reach's intestines, where mating takes place.
Clinical Features
• An unproductive cough and burning sensation, which may cause significant discomfort. Fever
is common at this stage.
• In established infections, patients are often asymptomatic.
• Serious infections, especially in children, large boluses of worms can cause pain and small
bowel obstruction, chronic abdominal discomfort, and growth retardation. Large nematodes
can enter and obstruct the biliary system, causing biliary colic, cholecystitis, and pancreatitis.
Diagnosis: Most cases of ascariasis can be diagnosed by microscopic detection of characteristic
roundworm eggs in feces.
Treatment:
Mebendazole 100 mg twice daily for 3 days
Piperazine 75 mg/kg (maximum 3.5 g) once daily for 2 days Pyrantelpamoate 10 mg/kg once
Albendazole 400 mg once is also valid.
Hookworm
An infection caused by two species of hookworms, Ancylostoma duodenale, and Necator
americanus. Worldwide distribution, however, older children have the highest incidence and
