Detection of fish pathogens by loop-mediated isothermal amplification (LAMP) technique

Abstract

Rapid detection of fish pathogens is mandatory for applying the crucial preventive and control measures to reduce fish losses and, consequently, minimize the economic impact of diseases on the fish farm owners. The currently used molecular diagnostic tools of fish infectious agents, such as PCR and RT-PCR, are sensitive and specific but still have some drawbacks. These tools are usually time consuming and laborious, need skilled persons, and require sophisticated devices to be performed. Therefore, next-generation tools for rapid diagnosis of fish infectious diseases were developed to conquer these shortages. One of these novel tools is the loop-mediated isothermal amplification (LAMP) technique. LAMP is considered a more advantageous tool than PCR because it needs only a heating block or a thermostatically controlled water bath as a source of constant temperature. It is considered to be more specific than the PCR assay as it uses 4-6 primers, which may diminish the occurrence of false-positive results. The time required for the amplification process by LAMP is ranging from 30 min to 1 h comparing to 3-5 h in the case of PCR. The visual detection methods coupled with the LAMP assay eliminates the post-run processing for detection of the amplification products. Its sensitivity is either comparable with the PCR or better than it. A variety of LAMP assays were developed for simple and rapid detection of a diversity of fish pathogens. Herein, we describe how to perform a LAMP assay and troubleshoot any potential problem arising during the process.