Loop-mediated isothermal DNA amplification for asymptomatic malaria detection in challenging field settings: Technical performance and pilot implementation in the Peruvian Amazon

PLoS One. 2017 Oct 5;12(10):e0185742. doi: 10.1371/journal.pone.0185742. eCollection 2017.

Abstract

Background: Loop-mediated isothermal DNA amplification (LAMP) methodology offers an opportunity for point-of-care (POC) molecular detection of asymptomatic malaria infections. However, there is still little evidence on the feasibility of implementing this technique for population screenings in isolated field settings.

Methods: Overall, we recruited 1167 individuals from terrestrial ('road') and hydric ('riverine') communities of the Peruvian Amazon for a cross-sectional survey to detect asymptomatic malaria infections. The technical performance of LAMP was evaluated in a subgroup of 503 samples, using real-time Polymerase Chain Reaction (qPCR) as reference standard. The operational feasibility of introducing LAMP testing in the mobile screening campaigns was assessed based on field-suitability parameters, along with a pilot POC-LAMP assay in a riverine community without laboratory infrastructure.

Results: LAMP had a sensitivity of 91.8% (87.7-94.9) and specificity of 91.9% (87.8-95.0), and the overall accuracy was significantly better among samples collected during road screenings than riverine communities (p≤0.004). LAMP-based diagnostic strategy was successfully implemented within the field-team logistics and the POC-LAMP pilot in the riverine community allowed for a reduction in the turnaround time for case management, from 12-24 hours to less than 5 hours. Specimens with haemolytic appearance were regularly observed in riverine screenings and could help explaining the hindered performance/interpretation of the LAMP reaction in these communities.

Conclusions: LAMP-based molecular malaria diagnosis can be deployed outside of reference laboratories, providing similar performance as qPCR. However, scale-up in remote field settings such as riverine communities needs to consider a number of logistical challenges (e.g. environmental conditions, labour-intensiveness in large population screenings) that can influence its optimal implementation.

MeSH terms

  • Adolescent
  • Child
  • Child, Preschool
  • DNA, Protozoan / genetics*
  • Female
  • Humans
  • Malaria / diagnosis*
  • Malaria / epidemiology
  • Malaria / parasitology
  • Male
  • Peru / epidemiology
  • Pilot Projects
  • Plasmodium / genetics
  • Prevalence
  • Real-Time Polymerase Chain Reaction

Substances

  • DNA, Protozoan

Grant support

This work was supported by FIND, through a grant from the German Government (Kreditanstalt für Wiederaufbau) to Dr Iveth J González. There was also a partial funding contribution to Dr Prof Anna Rosanas-Urgell from the Belgian Directorate-General for Development Cooperation (DGD) through the collaborative framework agreement 3 (FA3-DGD programme) between IMTAvH/UPCH (Peru) and ITM (Belgium), the Peruvian National Council of Science —Concytec (008-2014-FONDECYT) to Prof Dionicia Gamboa — and the Académie de Recherche et d’Enseignement Supérieur Commission de la Coopération au Développement of Belgium (ARES-CCD, PRD-Peru 2014-2019) to Prof Niko Speybroeck. ESC was supported by Fundación Alfonso Martín Escudero grant. Funding sources had no direct involvement on the study design, analysis, report writing or decision to submit for publication.