Biochemical, Physiological, and Immunological Changes Associated with Toxoplasma gondii Infection and Their Effects on Human Brain Health

Abstract

Toxoplasma gondii is an intracellular protozoan parasite infecting a large percentage of the world's population and potentially staying a long time in human tissues, especially in the central nervous system. The long-term consequences of chronic infection have been linked to neuroinflammation, immune dysfunction, oxidative damage and neurological issues. This study proposed to examine the physiological and immunological changes resulting from infection with Toxoplasma gondii and to assess changes in brain health in humans.

In this cross-sectional study, the age range was 20-60 years and the subjects were divided into four groups: healthy control, acute toxoplasmosis, chronic toxoplasmosis and treated patients with anti-parasitic drugs. The parameters were assessed for physiological, hematological, immunological, oxidative stress and neuroimaging parameters. Neurological examination, cognitive assessment and magnetic resonance imaging (MRI) were used to assess brain involvement, and serum levels of pro-inflammatory cytokines, anti-Toxoplasma antibodies, and oxidative stress biomarkers were determined by standard laboratory techniques.

Particularly, the participants with infection showed substantial changes, as compared to healthy controls (P < 0.05). Increased levels of TNF-α, IL-6, IFN-γ, and anti-Toxoplasma antibodies were also observed in acute and chronic toxoplasmosis, along with increased levels of oxidative stress markers and decreased levels of antioxidant capacity. Hematological changes (increase in WBC and changes in immune cell populations) were also observed. MRIs showed different extents of brain involvement, especially in the patients with chronic toxoplasmosis. The levels of inflammatory cytokines correlated positively with neurological abnormalities.

The Toxoplasma gondii infection causes a number of physiological, immunological and neurological changes in humans. During chronic infection, the brain may be involved due to the persisting inflammation and oxidative stress. The knowledge of these mechanisms can help to better diagnose, monitor and treat toxoplasmosis and its neurological effects.

Keywords: Toxoplasma gondii; Human toxoplasmosis; Neuroinflammation; Immune response; Oxidative stress; Brain involvement; Magnetic resonance imaging (MRI); Neurological manifestations