Comprehensive Overview of Toxoplasma gondii-Induced and Associated Diseases

Abstract

Toxoplasma gondii (T. gondii) is a prevalent protozoan parasite of medical and veterinary significance. It is the etiologic agent of toxoplasmosis, a neglected disease in which incidence and symptoms differ between patients and regions. In immunocompetent patients, toxoplasmosis manifests as acute and chronic forms. Acute toxoplasmosis presents as mild or asymptomatic disease that evolves, under the host immune response, into a persistent chronic disease in healthy individuals. Chronic toxoplasmosis establishes as latent tissue cysts in the brain and skeletal muscles. In immunocompromised patients, chronic toxoplasmosis may reactivate, leading to a potentially life-threatening condition. Recently, the association between toxoplasmosis and various diseases has been shown. These span primary neuropathies, behavioral and psychiatric disorders, and different types of cancer. Currently, a direct pre-clinical or clinical molecular connotation between toxoplasmosis and most of its associated diseases remains poorly understood. In this review, we provide a comprehensive overview on Toxoplasma-induced and associated diseases with a focus on available knowledge of the molecular players dictating these associations. We will also abridge the existing therapeutic options of toxoplasmosis and highlight the current gaps to explore the implications of toxoplasmosis on its associated diseases to advance treatment modalities.

Keywords: behavioral disorders; neurological disorders; neuropathies; psychiatric disorders; toxoplasmosis.

Figure 1

Summary of Toxoplasma gondii-induced diseases and their spectrum between immunocompetent and immunocompromised patients.

Figure 2

Summary of Toxoplasma gondii-associated primary neuropathy diseases and their outcome.

Figure 3

Summary of Toxoplasma gondii-associated psychiatric and behavioral disorders and the molecular status dictating these associations.