Intracellular Survival of Toxoplasma gondii: Success and Adaptation

Abstract

T. gondii was described as the most successful parasite on earth because of its wide range of host agents, intracellular adaptations and its ability to maintain continuous survival for the life span of its host. Its complex movement, penetration and intracellular replication within the host cell are organized in such a way that it invades and evades immune cells. Formation of parasitoporous vacoule within the host cells and strong anti-oxidant system, are factors that add to its ability to maintain itself in a latent stage, evasion of immune cells attack as well as the effects of reactive oxygen species. In immunocompetent individuals, the infection is asymptomatic, and the parasite exists and persists in a slowly replicating bradyzoite stage in skeletal muscle, heart, brain, retina, and placental tissues. Reactivation of the rapidly replicating tachyzoite stage in settings of immune-depression results with severe consequences.  This, therefore, prompts the need to understand certain mechanisms through which this organism succeeds and adapts the harsh condition of host cells during infection. The review further portrays the applicability of diagnostics and therapeutics to diagnose, treat and prevent infection with T. gondii.