Ascaris worms are very long. Adult females grow up to half a metre long, and males are15–31cm in length. They vary in diameter from 2–6mm.

Life cycle

  • ingested Ascaris eggs hatch out into larval worms in the intestine
  • worms pass through the intestine wall into the bloodstream
  • worms travel via the liver and heart into the lungs
  • after 3 weeks they are coughed up, swallowed and return to the gut
  • male and female worms mate and female worm produces eggs
  • eggs pass out in the stool and become infectious after 2 weeks in the soil