Toxoplasmosis and immunosuppression

Abstract

Toxoplasmosis is a widely distributed zooanthroponosis, caused by the ubiquitous obligatory intracellular protozoan parasite Toxoplasma gondii. Once infected, the host acquires lifelong immunity induced by the persistence of the parasite in an encysted form. While T. gondii infection in pregnancy has long been known as a significant cause of perinatal morbidity and mortality (congenital toxoplasmosis), its significance as an opportunistic agent has been increasingly recognized during the last decade, particularly with the outbreak of AIDS. Reactivation of a previously latent infection results in a wide clinical spectrum, predominantly within the central nervous system. The paper reviews recent data on the significance of toxoplasmosis as an opportunistic infection in immunosuppressed individuals, such as patients with malignant and systemic diseases treated with immunosuppressive drugs, organ transplant recipients, and, first and foremost, patients with AIDS. A high prevalence of latent toxoplasmosis in Yugoslavia indicates a high local exposure to infection reactivation. While a definitive diagnosis of toxoplasmosis is difficult in the immunosuppressed, its treatability as opposed to a fatal outcome, if untreated, demands that physicians caring for the above categories of patients keep in mind toxoplasmosis and its possible clinical presentations and include them in the differential diagnosis of these conditions.