The parasite, better known as hookworm, enters the body through the skin, usually through the soles of bare feet, and travels around the body until it attaches itself to the small intestine where it proceeds to suck the blood of its host. Over months or years it causes iron deficiency and anemia, weight loss, tiredness and impaired mental function, especially in children, helping to trap them into the poverty in which the disease flourishes.
https://www.theguardian.com/us-news/2017/sep/05/hookworm-lowndes-county-alabama-water-waste-treatment-poverty