Use of real-time multiplex PCR, malaria rapid diagnostic test and microscopy to investigate the prevalence of Plasmodium species among febrile hospital patients in Sierra Leone

Tomasz A Leski,Chris Rowe Taitt,Kathryn H Jacobsen,Nathanael D Reynolds,Victoria Baio,Chadwick Yasuda,Joseph M Lamin,Joseph Lahai,Andrew Holtz,Rashid Ansumana,Umaru Bangura,David A Stenger,Abdulai G Swaray

doi:10.1186/s12936-020-03163-2

Abstract

BackgroundMalaria continues to affect over 200 million individuals every year, especially children in Africa. Rapid and sensitive detection and identification of Plasmodium parasites is crucial for treating patients and monitoring of control efforts. Compared to traditional diagnostic methods such as microscopy and rapid diagnostic tests (RDTs), DNA based methods, such as polymerase chain reaction (PCR) offer significantly higher sensitivity, definitive discrimination of Plasmodium species, and detection of mixed infections. While PCR is not currently optimized for routine diagnostics, its role in epidemiological studies is increasing as the world moves closer toward regional and eventually global malaria elimination. This study demonstrates the field use of a novel, ambient temperature-stabilized, multiplexed PCR assay in a small hospital setting in Sierra Leone.MethodsBlood samples from 534 febrile individuals reporting to a hospital in Bo, Sierra Leone, were tested using three methods: a commercial RDT, microscopy, and a Multiplex Malaria Sample Ready (MMSR) PCR designed to detect a universal malaria marker and species-specific markers for Plasmodium falciparum and Plasmodium vivax. A separate PCR assay was used to identify species of Plasmodium in samples in which MMSR detected malaria, but was unable to identify the species.ResultsMMSR detected the presence of any malaria marker in 50.2% of all tested samples with P. falciparum identified in 48.7% of the samples. Plasmodium vivax was not detected. Testing of MMSR P. falciparum-negative/universal malaria-positive specimens with a panel of species-specific PCRs revealed the presence of Plasmodium malariae (n = 2) and Plasmodium ovale (n = 2). The commercial RDT detected P. falciparum in 24.6% of all samples while microscopy was able to detect malaria in 12.8% of tested specimens.ConclusionsWider application of PCR for detection of malaria parasites may help to fill gaps existing as a result of use of microscopy and RDTs. Due to its high sensitivity and specificity, species coverage, room temperature stability and relative low complexity, the MMSR assay may be useful for detection of malaria and epidemiological studies especially in low-resource settings.

Highlights

Malaria continues to affect over 200 million individuals every year, especially children in Africa
Plasmodium falciparum is responsible for 99% of malaria infections in Africa, while P. vivax causes the majority of infections in other parts of the world
This study explored the utility of a room temperaturestable, pre-aliquoted molecular assay for detection of malaria in a remote, low-resource location in West Africa

Summary

Introduction

Malaria continues to affect over 200 million individuals every year, especially children in Africa. Of the more than 200 million malaria cases estimated to occur each year, the overwhelming majority (90%) take place in sub-Saharan Africa [1]. Sierra Leone in particular has one of the highest burdens of malaria, with an estimated 3 million cases and 17,600 deaths occurring in 2017 [1]. Plasmodium falciparum is responsible for 99% of malaria infections in Africa, while P. vivax causes the majority of infections in other parts of the world. Plasmodium vivax and P. ovale require use of specialized anti-malarials to eliminate dormant stages that can cause relapses [5]. It is important for the malaria species to be determined as part of diagnosis

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