A.lumbricoides infection occurs worldwide, especially in underdeveloped nations. Accidentally ingested eggs hatch in the duodenum, penetrate the bowel wall to enter lymphatic channels and venules, pass through the liver and right heart, molt in the lungs, and ascend the tracheobronchial tree. Once in the hypopharynx, the worms are again swallowed and enter the bowel. Worms can grow to 50 cm in length and can cause bowel obstruction if present in large numbers.
A.lumbricoides is well known to enter the pancreatobiliary tree via the ampulla of vater, where the infection can cause jaundice, cholangitis, and pancreatitis. N. americanus (hookworm) does not invade the biliary tree. D. latum causes malnutrition and vitamin deficiencies but not biliary symptoms. P. ovale and P. falciparum are causative organisms of malaria.
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Seminars in Medical Practice
Hospital Physician Board Review Manuals
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