A highly sensitive molecular diagnosis method for detecting Toxoplasma gondii tachyzoite: a PCR/dot blot hybridization

This study aimed at finding a fast, sensitive, and efficient protocol for molecular identification of intracellular protozoa Toxoplasma (T.) gondii. For molecular detection of T. gondii, we developed a polymerase chain reaction coupled with dot blot hybridization assay (PCR/DBH). For DBH analysis, the amplified DNA of T. gondii tachyzoite was labeled by incorporation of digoxigenin. The DBH assay alone was capable of detecting down to 1×10 pg of T. gondii genomic DNA. The PCR alone was capable of detecting down to 1×10 pg of T. gondii genomic DNA, whereas the PCR/DBH assay was capable of detecting down to 1×10 pg of T. gondii genomic DNA, indicating that sensitivity of the PCR/DBH method was approximately 10 to 100 times higher than PCR or DBH alone. Our PCR/DBH assay will be useful for confirming the presence of T. gondii on the samples and differentiating T. gondii infection from other intracellular protozoa infections.