Journal des maladies tropicales et de la santé publique

Abstrait

Alternative Malaria Diagnostic Tools: Evaluation of Plasmodium falciparum Detection along Thailand?s Border by Loop-Mediated Isothermal Amplification (LAMP) and Immunochromatographic Test (ICT)

Salakchit Chutipongvivate*, Yongyut Prompunjai, Wanvisa Neadruengsang and Supaporn Wangsiricharoen

Introduction: Thailand has a national goal to eliminate malaria from 80 percent of the country by 2020. However, malaria-endemic areas still exist along the forested Thailand’s borders. An accurate and prompt diagnosis is the key to effective disease management. This aim of this study was to evaluate the application of LAMP as an alternative tool for falciparum malaria diagnosis of clinical suspicion of plasmodium infection in the border area, compared to those of ICT and microscopy using nested PCR as the reference detection method.

Materials and Methods: One hundred and four of blood samples were obtained from patients who were diagnosed malaria positive by clinical diagnosis or subjected to suffering from malaria as observed from clinical history. The primer set used for LAMP was designed on the basis of nucleotide sequence of 18S rRNA plasmodium gene and the ICT test was performed with the parasite lactate dehydrogease (pLDH) antigen-based lateral flow test.

Results: The LAMP assay has the highest agreement with the reference method (99.04%, κ=0.98) with a sensitivity (95%CI) of 98.59% (95.85-100.00) comparable to ICT and microscopy. Moreover, LAMP showed specificity 100% compared with 100% of ICT and 96.97% (91.12-100.00%) microscopy. Negative predictive value of LAMP and ICT were 97.06% and 82.50% respectively.

Conclusion: LAMP is useful and more reliable for specific diagnosis in border regions where malaria is endemic but individuals are asymptomatic and hence that LAMP could be the preferred method in resource-limited laboratories to progress towards malaria elimination in Thailand.