duodenale may probably also occur by the oral and the transmammary route. These larvae are capable of re-activating and establishing patent, intestinal infections. duodenale larvae, following penetration of the host skin, can become dormant (hypobiosis in the intestine or muscle). Most adult worms are eliminated in 1 to 2 years, but the longevity may reach several years. Adult worms live in the lumen of the small intestine, typically the distal jejunum, where they attach to the intestinal wall with resultant blood loss by the host. The larvae reach the jejunum of the small intestine, where they reside and mature into adults. They penetrate into the pulmonary alveoli, ascend the bronchial tree to the pharynx, and are swallowed. On contact with the human host, typically bare feet, the larvae penetrate the skin and are carried through the blood vessels to the heart and then to the lungs. These infective larvae can survive 3 to 4 weeks in favorable environmental conditions. These released rhabditiform larvae grow in the feces and/or the soil, and after 5 to 10 days (and two molts) they become filariform (third-stage) larvae that are infective. Eggs are passed in the stool, and under favorable conditions (moisture, warmth, shade), larvae hatch in 1 to 2 days and become free-living in contaminated soil.
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