[Parasitic infection in immunocompromised patients]

Several parasites are responsible for life threatening infections in immunocompromised patients. They occur in patients with a profound immunodeficiency affecting the T-cell mediated immunity. In AIDS patients, opportunistic infections are highly prevalent in those with CD4 lymphocyte counts < 200/mm3. Most of these parasites are intracellular protozoa. Severe parasitic infections in immunocompromised hosts either results from the reactivation of a previously acquired infection, such as toxoplasmosis, or from a primary acquired infection which manifests more severely because of the immune defect: this is the case for intestinal protozoa, such as Cryptosporidium, microsporidia, Cyclospora and Isospora belli which can be the cause of severe chronic diarrhea and for visceral leishmaniasis. Strongyloides stercoralis is the only helminth responsible for disseminated infection in immunocompromised patients. For each parasite, recommendations for preventing infection or specific chemoprophylaxis are efficient for prevention of opportunistic infections. Immune reconstitution also proved very efficient to reduce their incidence during VIH infection.