Description: This is an illustration of the life cycle of Ascaris lumbricoides, the causal agent of ascariasis. Adult worms image live in the lumen of the small intestine. A female may produce approximately 200,000 eggs per day, which are passed with the feces image. Unfertilized eggs may be ingested but are not infective. Larvae develop to infectivity within fertile eggs after 18 days to several weeks image , depending on the environmental conditions (optimum: moist, warm, shaded soil). After infective eggs are swallowed image , the larvae hatch image , invade the intestinal mucosa, and are carried via the portal, then systemic circulation to the lungs image. The larvae mature further in the lungs (10 to 14 days), penetrate the alveolar walls, ascend the bronchial tree to the throat, and are swallowed image. Upon reaching the small intestine, they develop into adult worms. Between 2 and 3 months are required from ingestion of the infective eggs to oviposition by the adult female. Adult worms can live 1 to 2 years. Source:
https://www.cdc.gov/dpdx/ascariasis/index.html https://www.cdc.gov/dpdx/ascariasis/modules/Ascariasis_LifeCycle_lg.jpg. Author: DPDx is an educational resource designed for health professionals and laboratory scientists. For an overview including prevention, control, and treatment visit www.cdc.gov/parasites/.