Adaptation of reverse transcription loop- mediated isothermal amplification for field diagnosis of foot-and- mouth disease in Tanzania

Foot-and-mouth disease (FMD) is a highly contagious viral vesicular disease of cloven hoofed animals and poses major constraints to international trade in livestock production. Methods available for detection of FMD virus (FMDV) require specialized laboratory facilities and equipment. In this study, targeted laboratory- based experiments studies were conducted using reverse transcription loop-mediated isothermal amplification (RT-LAMP) for detection and serotyping of FMDV under field conditions. Pan-serotypic RT-LAMP utilizing labeled and unlabeled primers was used for detection of the virus. Serotype-specific primers for FMDV serotypes A and O were used to type the positive samples using RT-LAMP. Amplification was observed in real-time for unlabeled primers and by molecular lateral flow devices for labeled primers. Also, gel electrophoresis was used for examination of deoxyribonucleic acid (DNA) bands. A total of 35 samples (n = 35) were examined using RT-LAMP. Of these, 40% (n=14) were positive from different regions in Tanzania. The positive samples were from Iringa with 29% (n=4), Morogoro with 14.2% (n=2), as well Kilimanjaro, Mara, Tanga, Tabora, Mtwara, Kagera Dar es Salaam and Mwanza with 7.1% (n=1) each. All the pan- serotypic RT-LAMP positive samples revealed time for positivity ranging from 12-30 minutes. These findings indicate that the standardized RT-LAMP assay reported in this study can be used for field detection of FMDV in suspected FMD outbreaks in Tanzania. These findings suggest a potential use of serotype-specific RT-LAMP for typing FMDV field strains