Toxoplasmosis: A Highly Complex Clinical Issue and a Diagnostic Challenge: Brief Overview

Toxoplasma gondii, a ubiquitous, compulsory, intracellular parasite was first discovered around 100 years ago. Toxoplasmosis, a common global zoonose, exhibits a marked variation of clinical manifestations, depending on the immune status of the host. In this regard, toxoplasma infection though usually latent in immune competent individuals, may cause severe disease, especially encephalitis, in the setting of immune suppression (acquired immune deficiency syndrome, solid organ transplantation, allogeneic hematopoietic stem cell transplantation-HSCT, immunosuppressive therapies). Noteworthy, cerebral toxoplasmosis has declined in view of widespread use of highly active antiretroviral therapy (HAART) in the cohort of AIDS patients. Congenital toxoplasmosis results almost solely from primary acquired maternal infection during gestation or from reactivation of latent infection in immunesuppressed pregnants. Chorioretinitis, hydrocephalus and intracranial calcifications consist the classic triad of symptoms. Ocular toxoplasmosis acquired either by congenital or postnatal routes, is the most common cause of posterior uveitis .This review is an effort to briefly summarize data on biological life cycle, trasmission routes of the parasite, as well as epidemiological, clinical, diagnostic features and aspects of toxoplasmosis in humans according to their immune background.