Infection of Ascaris usually occurs by :
Ingesting faecal matter
Ascariasis is an infection of the small intestine caused by Ascaris lumbricoides (A. lumbricoides), which is a species of roundworm. The eggs of the round worm is usually found in faecal matter and pesticides. A person can get infected with ascariasis after accidentally ingesting the eggs of the A. lumbricoides roundworm.