Ancylostoma duodenale is a type of parasitic roundworm, commonly known as a hookworm. It primarily infects humans and is found in tropical and subtropical regions. The adult worms live in the small intestine, where they attach to the intestinal wall and feed on blood, which can lead to anemia and other health issues. Transmission occurs when larvae penetrate the skin, often through bare feet in contaminated soil. Infected individuals may experience symptoms such as abdominal pain, diarrhea, and fatigue. Preventive measures include wearing shoes and improving sanitation to reduce exposure to contaminated environments.