Parasite

Parasites are an important cause of human disease worldwide millions of individuals died from Malaria, Chagas disease, African trypanosomiasis, strongyloidiasis, amebiasis, leishmaniasis, ascariasis and schistosomiasis. The clinical severity and outcome of parasitic disease is often dependent on the immune status of the host. Humans protect themselves from parasites using a variety of defenses, including nonspecific immunity (e.g., mucosal barriers, pH, temperature), innate mechanisms (e.g., complement, toll-like receptors) and adaptive immune mechanisms (e.g., pathogen-specific humoral and cell-mediated responses). In general, helminths elicit a protective helper T-lymphocyte type 2(Th2) host response with production of IgE, eosinophilia and mastocytosis, while protozoa elicit a humoral and/or cellular immune response that is not generally associated with eosinophilia. Conditions that compromise host immunity, thus making individuals more susceptible to parasitic infections and associated disease complications, include primary or acquired immunodeficiencies, receipt of immunosuppressive therapies, malnutrition, and asplenia. Neonates, the elderly and those with chronic disease may also be at increased risk of acquiring or suffering severe consequences from parasitic infections.