Use of FTA Cards for DNA Preservation and Dual-LAMP Analysis of Plasmodium knowlesi and P. cynomolgi.

OBJECTIVE: The emergence of zoonotic malaria caused by Plasmodium knowlesi and P. cynomolgi presents growing challenges for malaria diagnosis in Southeast Asia. Reliable sample preservation and rapid molecular detection are particularly important in remote endemic areas where cold-chain facilities are often unavailable. Although molecular techniques provide highly sensitive and specific diagnostic tools, their application in field settings remains challenging. Consequently, FTA cards have gained increasing attention as a practical approach for the rapid collection, transport and long-term archiving of biological samples.

METHODS: In this study, DNA extracted from FTA cards was evaluated using dual loop-mediated isothermal amplification (dual-LAMP) assays for parasite detection. Whole blood samples were spotted onto FTA cards, processed using a modified lysis-based protocol, and directly used as templates in dual-LAMP assays without further DNA purification.

RESULTS: Both colorimetric and fluorescent LAMP assays demonstrated high specificity, with no cross-reactivity against other human malaria parasites. The assays also showed comparable analytical sensitivity, with detection limits of 1 copy/µL for P. cynomolgi and 10 copies/µL for P. knowlesi.

CONCLUSION: FTA cards proved to be a faster and more cost-effective alternative to commercial DNA extraction kits. In addition, they maintained DNA stability at room temperature without the need for cold storage, making them highly suitable for field applications and reducing degradation risks during sample transportation. Combination of FTA card-based lysis and dual-LAMP provides a robust approach for malaria parasite detection.