1. Life cycles of Ancylostoma duodenale and Necator americanus (human hookworms). Penetration of the skin by infective hookworm larvae is followed by migration of larvae from the skin, through the bloodstream to the heart and lungs, and then via the bronchi, trachea, and mouth to the intestine, where the bloodsucking worms pair, mate, and release eggs in feces. 1–6: In (1), a pair of copulating adult worms is shown attached to the intestinal mucosa. An egg at the tetranucleated stage (2) is passed in feces. In (3) is shown an embryonated egg prior to hatching in soil. Rhabditiform larvae in soil (4) molt to produce infective filariform larvae, still loosely covered by the protective second-stage larval sheath (5). The infective larvae rapidly respond to nearby human skin, become extremely active, and penetrate the skin upon contact (6). (Reproduced, with permission, from Goldsmith R, Heyneman D [editors]. Tropical Medicine and Parasitology. Originally published by Appleton & Lange. Copyright © 1989 by The McGraw-Hill Companies, Inc.)
Source: Protozoal & Helminthic Infections, Current Medical Diagnosis & Treatment 2017
Citation: Papadakis MA, McPhee SJ, Rabow MW. Current Medical Diagnosis & Treatment 2017; 2016 Available at: Accessed: November 14, 2017
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