Abstract

Amany A. Abd El-Aal *, Maysa M Kamel , Eman y shoeib , Fawzia A Habib , Manal Barakat , Lamia A. El-Housseiny

Serological diagnosis of active Toxoplasma infection is unreliable because reactivation of latent, hidden infection is not always accompanied by changes in antibody levels, and the presence of IgM does not necessarily indicate recent infection. Data concerning the relation between the severity of infection and the parasitic load especially at human level is limited. A trial was done in this work to study the relationship between the virulence of the parasite in different clinical forms and parasitic genomic load, via SYBR® Green quantitative PCR amplification assay and primers targeting Toxoplasma B1 gene. Fluorescence signals were generated from 91 samples, which were as follow; 7 cases with congenital manifestations, 19 cases with neurological disorders, and 65 asymptomatic cases. The seven congenitally infected cases showed significantly higher parasite load (5.15x 108 to 9x 1010). Other clinical forms showed genomic concentration ranged from 1.7x 104 to 4.1x 108 . Equal copy numbers of template did not produce equal parameters on derivative melting curve plots. In conclusion, quantitative polymerase chain reaction (PCR) provides a sensitive and practical method not only for gene quantification, but also for gene scanning by melting curve analysis which is highly recommended for different Toxoplasma genes especially those with known pathological functions.