Abstract: Objective To detect Toxoplasma gondii DNA by loop-mediated isothermal amplification（LAMP）. Methods DNA was extracted by phenol-chloroform extraction from T. gondii tachyzoites. Four primers which recognized 6 distinct regions on the B1 gene of T. gondii were designed and used for LAMP assay. To evaluate the specificity of the method， Plasmodium vivax， P. falciparum， Pneumocystis carinii， Schistosoma japonicum， and mouse leucocytes were used as controls. The parasite extract （T. gondii） was 10-fold serially diluted for evaluating the sensitivity of LAMP, and was amplified by LAMP. LAMP results were read with naked eye and analyzed by electrophoresis. Results After LAMP reaction， positive amplification was observed with T. gondii, but no positive signal was toted for the negative controls in the study. The sensitivity of LAMP assay reached up to 2-3 T. gondii tachyzoites/ml per reaction. Conclusion LAMP assay shows proper specificity and sensitivity for the detection of T. gondii.

Key words: Toxoplasma gondii, Detection, Loop-mediated isothermal amplification