Parasitic diseases and immunodeficiencies

In the last two decades, major immunodeficiency syndromes have strongly inf luenced medical parasitology. Some animal parasitoses, once unknown in huma n medicine, hare become zoonotic and sometimes anthroponotic. In other case s, the clinical evolution of human parasitoses has been severely aggravated and/or modified in immunodeficient patients especially in toxoplasmosis, c ryptosporidiosis, leishmaniasis, strongyloidiasis and scabies. The parasite s implicated are varied (protozoa, helminths and el en Acaridae) but have i n common the capacity to reproduce in or on the human host. These immunodef iciency syndromes are often related to AIDS but other major immunodepressio ns, such as post-therapeutically in organ transplantation, ma) also be resp onsible and raise difficult problems for prevention. The immunological mech anisms involved are not always well understood. In addition, genetic predis position factors, gradually becoming better-understood in parasites and man , complete and complicate our understanding of the immunological mechanisms .