Hookworms commonly occur in warm, moist climates such as northern KwaZulu-Natal and the Mozambique coast. With poor sanitation, hookworm eggs in the stool contaminate the soil and hatch rapidly. They then infect the feet of barefoot children. Once the skin is penetrated, hookworms behave like roundworms as they enter the bloodstream and travel via the lungs to get into the small bowel. The worms attach to the bowel mucosa and cause bleeding.
There are two types of hookworm, Ancylostoma duodenale and Necator americanus.