Three species of hookworms commonly infect humans: Ancylostoma duodenale, Necator americanus and Strongyloides stercoralis. A. duodenale predominates in the Middle East, North Africa, India and (formerly) in southern Europe, while N. americanus predominates in the Americas, Sub-Saharan Africa, Southeast Asia, China, and Indonesia. The A. braziliense and A. tubaeforme species infect cats, while A. caninum infects canines.