Abstract: Newcastle disease viruses (NDV) were detected by three detecting tests and make a comparison of sensitivity and specificity about these tests. A total of six primers were designed and synthesized based on the fusion gene of NDV and were used for isothermal amplification of nucleic acid. The LAMP reaction conditions were optimized and nucleic acid amplification were detected in optimized temperature by LAMP turbidimetry. Detection of gene amplification could be accomplished by agarose gel electrophoresis. It was found that the detection limit of the water bath LAMP assay was 1.58 pg,it demonstrated 100-fold higher sensitivity than PCR,the detection limit of the LAMP turbidimetry assay was 15.8 ng and 10-fold higher sensitivity than the water bath LAMP,which had no cross-reaction with other viruses. The water bath LAMP was very simple and amplification can be obtained without extremely sophisticated instrumental. The water bath LAMP assay was extremely convenience,highly sensitive and specific and had potential replaced PCR in the field of nucleic acid amplification. LAMP turbidity assay was more sensitive,but required more expensive equipments and reagents.

Key words: loop-mediated isothermal amplification; Newcastle disease virus; PCR; LAMP turbidimetry