Ascaris lumbricoides (giant roundworm)

Ascaris lumbricoides is a soil-transmitted helminth (parasitic) worm. It is common in tropical and sub-tropical regions and causes a disease called ascariasis.

People become infected when they ingest worm eggs from soil.

It lives and reproduces inside its human host.

The worm cleverly works its way through the body from the gut, via the liver and heart, to the lungs and back to the gut.

Symptoms of the disease vary, and some people don’t even realise they are infected (they are 'asymptomatic').

People infected with multiple worms experience diarrhoea, abdominal pain, general malaise and weakness. These symptoms can affect people’s ability to work and learn, and can impair physical growth.

Species detail

The ascaris worm can reach half a metre in length.

Biology

Discover how these highly successful worms reproduce in their human hosts and find out more about the ascariasis - the disease they cause.
Behaviour

Ascaris worms have infected over a billion people world-wide. But how do they do it, and what’s being done to control them?