Evaluation of FTA® card for the rescue of infectious foot-and-mouth disease virus by chemical transfection of extracted RNA in cultured cells

Foot-and-mouth disease (FMD) is a highly contagious epidemic disease of transboundary importance. Inadequate storage and shipment of suspected clinical samples can compromise the ability to detect and characterise FMD virus (FMDV) in endemic countries, thereby, leading to the loss of valuable virological and epidemiological data. This study, investigates the potential of using FTA® cards for dry transportation of clinical samples and subsequent recovery of infectious FMDV by chemical transfection of FTA® card fixed RNA as an alternative to the conventional cell culture based virus isolation method. A higher proportion of infectious FMDV was rescued from clinical samples (cell culture isolates, tongue epithelial suspension and impression smears) by the FTA® card fixed RNA transfection method (76%) compared to the conventional cell culture based virus isolation (56%), suggesting a better performance of the current RNA transfection procedure. Furthermore, it was possible to rescue live virus by the transfection of RNA extracted from FTA® card impregnated with clinical samples that had been stored at varying temperature (4-37 °C) up to a period of six weeks. The VP1 sequence data and antigenic relationships with the vaccine strains, between viruses rescued by FTA® card fixed RNA transfection and conventional cell culture, were comparable. Therefore, these results support the use of the FTA® card for the economic, dry, non-hazardous transport of FMD suspected clinical samples from the site of collection to national/international reference laboratories.