Development of a loop-mediated isothermal amplification (LAMP) assay targeting the mitochondrial cytochrome b gene for the rapid detection of alveolar echinococcosis in hepatic nodules of horses

Alveolar echinococcosis, which is caused by a larval-stage infection of Echinococcus multilocularis, is a zoonosis with public health importance. Recently, alveolar echinococcosis in slaughtered horses has been reported in Japan and Poland. In terms of public health, a highly sensitive and specific diagnostic method is essential for early detection during meat inspection. In this study, the loop-mediated isothermal amplification (LAMP) assay was developed and validated to target the mitochondrial cytochrome b (cob) gene of E. multilocularis. Forty-one hepatic solid nodules obtained from each horse were evaluated based on histopathological examination and cob-targeted PCR and then submitted to the LAMP assay. The optimal condition of the developed LAMP assay was 64℃ for 30 min. The results of the developed LAMP assay were completely consistent with those of cob PCR. In addition, the detection limit for the number of copies of the cob gene was 135 copies/μL in the LAMP assay. These findings suggest that the ability of the LAMP assay developed in this study is equivalent to that of the conventional PCR testing. The LAMP assay developed in this study can be used as an alternative to PCR testing for the routine genetic diagnosis of alveolar echinococcosis in horses.