Rapid diagnosis of Tetracapsuloides bryosalmonae, the causative agent of proliferative kidney disease (PKD) in salmonid fish by a novel DNA amplification method, loop-mediated isothermal amplification (LAMP)

A new molecular diagnostic assay was developed for detection of Tetracapsuloides bryosalmonae the causative agent of proliferative kidney disease (PKD) in salmonid fish using a loop-mediated isothermal amplification method (LAMP). The PKD-LAMP assay amplifies the T. bryosalmonae DNA extracted from infected kidney, under constant temperature of 65°C within 1 h. The required equipment for DNA amplification is only a water bath. The amplification products were detected visually by using SYBR green I dye, which turns green in the presence of amplified products and remains orange in its absence, and by electrophoresis without any difference in the sensitivity of both methods. The developed PKD-LAMP assay demonstrated an exceptionally higher sensitivity than the conventional PCR. PKD-LAMP assay was found to be 100-fold more sensitive than the PCR assay. The developed assay is simple, rapid, cost-effective, specific and highly sensitive. The assay is also characterized by its field applicability, as it does not require the use of sophisticated equipment or skilled personnel.