Hookworm infections in human and laboratory animals--differences and similarities in immune responses.

Hookworm infection is one of the most important parasitic infections of humans. About 740 million people are infected with Ancylostoma duodenale and Necator americanus in the tropics and subtropics. Unlike most other human helminth infections, neither age nor exposure-related immunity develops in the majority of infected people. This review presents the contemporary knowledge concerning the immune response to this complex eukaryotic parasite, recent findings on the human cellular immune responses to hookworms, as well as mechanisms used by the parasite to modulate the immune response in its favor. Also immunological responses in animal models of hookworm infection are presented. Animals in contrast to humans seem to easily deal with hookworm infections and gain protection during re-exposure.