Ascariasis is an infection caused by roundworms of the genus Ascaris (hence called Ascariasis) which occur worldwide. Ascaris lumbricoides looks like a garden earthworm. Eggs get ingested from soil contaminated with human faeces, either directly or from poorly washed raw vegetables. In a bad infection there are 20 or more worms passed in their faeces each time a person goes to toilet. Prolonged infection can delay the development of mental and motor skills in infants and temporarily impair the ability of school-age children to understand and learn. A tangle of worms can obstruct the gut and might even need surgery to be removed. There is an effective drug treatment. The spread of the infection and recurrent infection can be reduced by better hygiene, especially hand washing, and good sanitation.
Ascariasis caused 0.006% of all deaths worldwide in 2002, with an average of 0.5 deaths per million people.