[Opportunistic aspects of parasitosis].

Parasitosis opportunist are becoming clearer thanks to a better knowledge of immunological mechanisms, especially in AIDS. Child immunological immaturity and corticotherapy are the two other main immunodeficiencies among opportunist parasitosis. For the protozoosis, coccidiosis (especially toxoplasmosis), cryptosporidiosis, but isosporosis too and microsporidiosis represent a privileged group among opportunistic infections. Among adult, leishmaniasis caused by L. infantum is an opportunist parasistosis, favoured by corticotherapy or AIDS, but among children, it is the child's immunological immaturity which is involved in the immunodeficiency. Babesia occurs among splenectomized people. Giardiasis is more frequent and more severe among IgA immunodeficiencies especially secretories IgA. Among helminthiasis, generalised strongyloidiasis is very severe among patients under corticotherapy, but AIDS is not involved.