Validation of a novel FRET real-time PCR assay for simultaneous quantitative detection and discrimination of human Plasmodium parasites

PLoS One. 2021 Jun 4;16(6):e0252887. doi: 10.1371/journal.pone.0252887. eCollection 2021.

Abstract

Increasing numbers of travelers returning from endemic areas, migrants, and refugees have led to a significant rise in the number of imported malaria cases in non-endemic countries. Real- time PCR serves as an excellent diagnostic tool, especially in regions where experience in microscopy is limited. A novel fluorescence resonance energy transfer-based real-time PCR (FRET-qPCR) was developed and evaluated using 56 reference samples of the United Kingdom National External Quality Assessment Service (UK NEQAS) for molecular detection of malaria, including P. falciparum, P. vivax, P. ovale, P. malariae, and P. knowlesi. Species identification is based on single nucleotide polymorphisms (SNPs) within the genome where the MalLC640 probe binds, lowering the melting temperature in the melting curve analysis. The novel FRET-qPCR achieved 100% (n = 56) correct results, compared to 96.43% performing nested PCR. The high sensitivity, with a calculated limit of detection of 199.97 parasites/mL blood for P. falciparum, is a significant advantage, especially if low-level parasitemia has to be ruled out. Even mixed infections of P. falciparum with P. vivax or P. ovale, respectively, were detected. In contrast to many other real-time PCR protocols, this novel FRET-qPCR allows the quantitative and species-specific detection of Plasmodium spp. in one single run. Solely, P. knowlesi was detected but could not be differentiated from P. vivax. The turnaround time of this novel FRET-qPCR including DNA extraction is less than two hours, qualifying it for routine clinical applications, including treatment monitoring.

Publication types

  • Validation Study

MeSH terms

  • DNA, Protozoan / analysis
  • DNA, Protozoan / genetics*
  • Fluorescence Resonance Energy Transfer / methods*
  • Humans
  • Malaria / diagnosis*
  • Malaria / epidemiology
  • Plasmodium / classification*
  • Plasmodium / genetics*
  • Plasmodium / isolation & purification
  • Real-Time Polymerase Chain Reaction / methods*
  • United Kingdom / epidemiology

Substances

  • DNA, Protozoan

Grants and funding

The authors received no specific funding for this work.