Seroprevalence and Genetic Characterization of Toxoplasma gondii among Children with Neurodevelopmental Disorders in Egypt

Abstract

Toxoplasma gondii is a parasite with a special predilection for the central nervous system. Toxoplasmosis's contribution to the triggering of many neurodevelopmental disorders was established. This study aimed to detect the seroprevalence and genotypes of T. gondii strains in children with neurodevelopmental disorders. The study included 180 children with neurodevelopmental disorders and 180 children in the control group. Assessment of seropositivity of Toxoplasma IgM and IgG antibodies in patients and controls was carried out. Genetic characterization of T. gondii was obtained by nested polymerase chain reaction (PCR) and restriction fragment length polymorphism (RFLP) technique targeting dense granule gene (GRA6). Our results showed that the overall seroprevalence of T. gondii antibodies in the patient and controls was 35.6% and 11.7%, respectively. Nested PCR showed positivity in 11.1% of the patient group for T. gondii DNA. T. gondii seropositivity rate was significantly high in patients with hydrocephalus and also in patients with epilepsy. Positive nested PCR was significantly high in children with hydrocephalus only. Genotyping using nested PCR-RFLP showed genotype I (80%) followed by atypical strains (20%) with no association with any specific clinical presentation. In conclusion, among toxoplasmosis-positive children with neurodevelopmental disorders, analysis of T. gondii GRA6 locus revealed the predominance of type I genotype followed by atypical strains.

A systematic review and meta-analysis of protozoan parasite infections among patients with mental health disorders: an overlooked phenomenon

“…Similarly, our subgroup meta-analysis of cross-sectional studies based on the type of mental disorder indicated that, patients with neurodevelopmental disorder followed by patients with bipolar and related disorders had the highest prevalence rate of toxoplasmosis. Previous studies showed that the seropositivity rates of anti- Toxoplasma antibodies were significantly higher in patients with neurodevelopmental disorders than in controls [ 29 – 32 ]. Furthermore, a meta-analysis study on 4021 patients diagnosed with bipolar disorder and 8669 healthy controls indicated that this disorder was associated with 1.34-fold higher risk of seropositivity for toxoplasmosis than healthy individuals [ 33 ].…”

Genetic diversity of Toxoplasma gondii in South America: occurrence, immunity, and fate of infection

“…Non-archetypal strains have also been identified in cases of congenital toxoplasmosis, and were associated with severe infection [ 102 ]. In Egypt, T. gondii seropositivity was found to be significantly higher in children with hydrocephalus and epilepsy; the presence of non-archetypal strains was confirmed by PCR–RFLP [ 103 ]. The strain should also be taken into consideration as a potentially important factor in the case of pregnant women, as it may have an impact on fetus survival, as well as on the severity of a newborn’s ocular and/or cerebral impairment [ 104 ].…”