Hookworm infection

The hookworm life cycle

The larvae and adult worms live in the small intestine (small bowel) of an infected person or animal.

If an infected person defecates outside (for example, near bushes or in a field) or if their stools are used as fertiliser, the hookworm eggs in the stools will contaminate the soil.

The eggs hatch in the soil after one to two days and release larvae, which are too small to be visible. The larvae develop into amature form after 5 to 10 days, which can penetrate human skin.

The main way people become infected with hookworm is through direct skin contact with contaminated soil, typically when walking barefoot. Children can also become infected after playing in the soil and putting their hands in their mouth.

Other ways to become infected include eating raw, unwashed vegetables that are contaminated with hookworm eggs or by drinking contaminated water.

Once the larvae have entered the body, they move through the bloodstream into the lungs, airways and throat, where they're swallowed and enter the small intestine.

After reaching the small intestine, the larvae mature into adult worms and attach themselves to the intestinal wall, where they can cause blood loss. Most adult worms are expelled from the small intestine after one to two years, although they can sometimes remain for longer.

The two main species of hookworm that infect people are Ancylostoma duodenale and Necator americanus.