Transmission
You can get hookworms by walking barefoot over contaminated soil. In penetrating your skin, the hookworm larvae (immature worms) may cause an allergic reaction. It is from the itchy patch at the place where the larvae entered your body that the early infection came to be known as "ground itch."
Once larvae have broken through your skin, they enter your bloodstream and are carried to your lungs. Unlike ascarids, another form of parasitic roundworm, hookworms do not usually cause pneumonia.
The larvae migrate from your lungs to your windpipe, which is then swallowed and carried back down to your small intestine.