Toxoplasmosis

Toxoplasmosis is a disease caused by a parasite called Toxoplasma gondii (T. gondii). It is an intracellular parasite in the phylum Apicomplexa, and its life cycle completed only in cats and other felids (the definitive host). However, T. gondii also infects a wide variety of intermediate hosts, including humans (Wastling et al., 2000).
Humans get infection either by the ingestion of tissue cysts in infected meat or by the ingestion of water or food contaminated with sporulated oocysts derived from the surrounding environment or, less frequently, directly from feline feces (Cook et al., 2000).
Most immunocompetent individuals who catch the infection do not develop symptoms, or may suffer from nonspecific symptoms as fever, headache, myalgia and lymphadenopathy (Saadatnia and Golkar, 2012). The
Prevalence of toxoplasmosis varies between 15-85%, most likely because of cultural practices as eating undercooked meat and the amenability of the climate towards the Toxoplasma oocysts survival in soil (John and Petri, 2006).
There is a growing interest in the role of microbial agents in the causation of psychiatric disorders. Toxoplasma gondii is one of the main candidates and has been associated with various psychiatric conditions, including schizophrenia (Fekadu et al., 2010).
The dopamine imbalance between the mesolimbic and the mesocortical regions in the brain is suspected to play a role in the development of schizophrenia. This may permit a relationship between schizophrenia and toxoplasmosis (Skallova et al., 2006).
Schizophrenia is one of the most prevalent and severe psychiatric diseases, with onset often in young adulthood. It is characterized by impairment in thought processing, perception, cognition, mood, and psychomotor behaviour (Buckley et al.,