Almost more than any other parasitic disease, inadequate personal hygiene leads to ascariasis. Human feces found in fields, streets, and yards are a major source of infective eggs in heavily populated areas.
The eggs do not infect humans when first excreted by the roundworm. They usually are transmitted by hand to mouth. The use of human feces as fertilizer also may permit transmission of infective eggs through food that is grown in the soil and eaten without being thoroughly washed. The eggs are resistant to extremes of temperature and humidity.
The eggs need several weeks to develop and become infective. If you swallow infective eggs, they pass into your intestines where they hatch into larvae and then begin their journey through your body.
The worms become mature in about 2 months.
Last Updated September 12, 2007
Last Reviewed May 12, 2011