Evaluation of the Performance of Rapid Diagnostic Tests for Malaria Diagnosis and Mapping of Different Plasmodium Species in Mali

Abstract

Background: The first-line diagnosis of malaria in Mali is based on the use of rapid diagnostic tests (RDT) that detect the Histidin Rich Protein 2 (HRP2) antigen specific to Plasmodium falciparum. Our study, based on a real-time polymerase chain reaction (qPCR) gold standard, aimed to describe the distribution of the Plasmodium species in each administrative region of Mali and to assess the performance of RDTs.

Methods: We randomly selected 150 malaria-negative and up to 30 malaria-positive RDTs in 41 sites distributed in 9 regions of Mali. DNA extracted from the RDT nitrocellulose strip was assayed with a pan-Plasmodium qPCR. Positive samples were then analyzed with P. falciparum-, P. malariae-, P. vivax-, or P. ovale-specific qPCRs.

Results: Of the 1496 RDTs, 258 (18.6%) were positive for Plasmodium spp., of which 96.9% were P. falciparum. The P. vivax prevalence reached 21.1% in the north. RDT displayed acceptable diagnostic indices; the lower CI95% bounds of Youden indices were all ≥0.50, except in the north (Youden index 0.66 (95% CI [0.44-0.82]) and 0.63 (95% CI [0.33-0.83].

Conclusions: Overall, RDT diagnostic indices are adequate for the biological diagnosis of malaria in Mali. We recommend the use of RDTs detecting P. vivax-specific antigens in the north.

Keywords: Malaria; Mali; PCR; Plasmodium species; rapid diagnostic tests; sensitivity; specificity.

Figure 1

Location of the study sites in the nine administrative regions of Mali where malaria is endemic.

Figure 2

Plasmodium species distribution in the nine administrative regions of Mali where malaria is endemic.

Figure 3

Amplification curves for real-time PCR targeting 18S rRNA of Plasmodium vivax species in Menaka (positive control in red and positive samples in green).