Hookworms are intestinal parasites of mammals, including humans, dogs, and cats; in humans these infections are a leading cause of intestinal blood loss and iron-deficiency anemia. Hookworm infections occur mostly in tropical and subtropical climates and are estimated to infect about 1 billion people worldwide-- about one-fifth of the world's population. People who have direct contact with soil that contains human feces in areas where hookworm is common are at high risk of infection; because children play in dirt, they are at the highest risk.
These results set the stage for the next stage of vaccine development in humans. Loukas and colleagues suggest that the ideal hookworm vaccine would be a mixture of two recombinant proteins, targeting both the infective larva and the blood-feeding adult stage (as targeted here) of the parasite. Such a vaccine would limit the amount of blood loss caused by feeding worms and maintain normal levels of hemoglobin.