Development and validation of loop-mediated isothermal amplification (LAMP) method for rapid and reliable diagnosis of foot and mouth virus serotypes in Türkiye

Foot and mouth disease is the disease of ungulate animals with and acute course and high economic loss. There are seven different serotypes of the foot-and-mouth disease virus and the serotypes of A,O and Asia 1 are seen in Turkey. However, serotype Asia 1 has not been detected since 2015 and serotype A since 2018 January. The fight against foot and mouth disease is of great importance all over the world. Since culling is not yet included in the current control and intervention programs in our country, early diagnosis of the disease and quarantine measures are taken quickly. Animal movement restrictions and vaccination are the main elements in effective intervention and control. An ideal diagnostic method should be specific, sensitive, rapid and economical. Molecular diagnostic methods are tests that give faster results than in-vitro virus isolation and serological tests. Even the cost of the most well-known molecular diagnostic method, polymerase chain reaction (PCR) challenges laboratories economically. Loop-mediated Isothermal Amplification (LAMP) method based on nucleic acid amplification was developed in the 2000s in order to develop a fast, specific and sensitive diagnostic method with cost-effective equipment in the field or in low-budget laboratories, and studies were carried out in the diagnosis of many viral diseases. Since the LAMP method, with its simple working principle, does not require heat exchanges, it ensures that the devices are more economical than other molecular diagnostic devices (PCR, etc.), and in the absence of the device, it is possible to create amplified products with a heat block or water bath that can be adjusted to a constant temperature. Due to the nature of the reaction that occurs, simple end-point systems can be used in addition to fluorescent dyes or turbidimeter devices during the result evaluation phase. The fact that it is easer to use and more accessible compared to other molecular diagnostic methods, and the evaluation that the sensitivity is 1000 times higher than conventional PCR in some studies has laid the groundwork for the development of this diagnostic method to detect strains in our country and to compare it with conventional and real-time PCR methods. Despite the improvement of PCR mastermixes and devices with the recently developed technology, a PCR test with 35-40 cycles takes at least 1,5-2 hours, while this time is between 30-60 minutes with LAMP. In this study, serotypes will be determined by optimizing and validating LAMP diagnosis with archival samples and the results will be compared with conventional PCR and rt-RT-qPCR.