Diagnostic application of formalin fixed archived tissues for detection of foot-and-mouth disease

Early and definitive disease diagnosis is critical for effective disease control. 50% buffered glycerine is commonly used viral transport medium, which is not always available and required cold chain. Tissues samples archived in 10% neutral buffered formalin (NBF) can preserve nucleic acid that can be used in molecular studies and disease diagnosis. The present study's goal was to detect the foot-and-mouth disease (FMD) viral genome in formalin-fixed archived tissue which may avoid cold chain during transportation. This study used FMD suspected samples preserved in 10% neutral buffered formalin from 0 to 730 days post fixation (DPF). All archived tissues were positive for FMD viral genome by multiplex RT-PCR and RT-qPCR up to 30 DPF, whereas archived epithelium tissues and thigh muscle were positive for FMD vial genome up to 120 DPF. FMD viral genome was detected in cardiac muscle up to 60 DPF and 120 DPF, respectively. The findings suggest that 10% neutral buffered formalin could be used for sample preservation and transportation for timely and accurate FMD diagnosis. More samples need to be tested before implementing the use of 10% neutral buffered formalin as a preservative and transportation medium. The technique may add value in ensuring biosafety measures for creation during disease free zone as well.