Performance of PURE-LAMP to Detect Declining Prevalence of Malaria in Haiti

Abstract

Background Malaria continues to cause burden in various parts of the world. Endemic countries are developing schemes to end this nuisance in accordance with the World Health Organization’s Global Technical Strategy for Malaria 2016–2030. Haiti, a Caribbean country, is among those aiming to eliminate malaria within a few years. Two surveys were conducted in Haiti in the summers of 2017 and 2018, respectively, during which we aimed to evaluate the performance of the simple and rapid PURE-LAMP (procedure for ultra-rapid extraction–loop-mediated isothermal amplification) method with dried blood spots as an alternative diagnostic method for malaria in the context of low to very low rates of transmission.Methods Febrile and asymptomatic subjects were recruited from three administrative divisions within Haiti. Their blood samples were tested by microscopy, rapid diagnostic tests (RDT), PURE-LAMP and nested PCR to detect Plasmodium infection. The positive rates for the two study periods as determined by the different methods were compared. Sensitivity, specificity, positive and negative predictive values and kappa statistics were estimated with the nested PCR results as the gold standard.Results Among 1074 samples analyzed, a positive rate of 8.3% was calculated based on the nested PCR results. Among symptomatic subjects, the rates in 2017 and 2018 were 14.6% and 1.4%, respectively. Three positives were detected among 172 asymptomatic participants in 2018 by PURE-LAMP and nested PCR, and all three were from the same locality. No asymptomatic subjects were recruited in 2017. The PURE-LAMP, RDT and microscopy had respective sensitivities of 100%, 85.4% and 49.4%. All of the testing methods had specificities over 99%.Conclusion The prevalence of malaria was found to have substantially decreased in 2018 in Haiti. A specific focus of infection appeared to require intervention with a sensitive malaria diagnostic method and treatment. This study confirmed the high performance of the PURE-LAMP method with dried blood spots and recommends its use in targeted mass screening and treatment activities in low endemic areas of malaria.