Symptomatic Plasmodium vivax Infection in Rwanda

Abstract

We report a Plasmodium vivax infection in a Rwandan child misdiagnosed with Plasmodium falciparum and administered artemether-lumefantrine. Antigen detection revealed an absence of P falciparum histidine-rich protein 2 (HRP2) and presence of Plasmodium vivax lactate dehydrogenase. Nested and real-time polymerase chain reactions verified that the sample only contained P vivax deoxyribonucleic acid.

Keywords: PCR; Plasmodium vivax; microscopy; misdiagnosis; multiplex.

Figure 1.

Detection of Plasmodium vivax antigens, antibodies, and deoxyribonucleic acid (DNA). (A) Bead-based multiplex antigen detection assay for pan-Plasmodium aldolase (pAldolase) and pan-Plasmodium lactate dehydrogenase (pLDH), P vivax lactate dehydrogenase (PvLDH), and Plasmodium falciparum histidine-rich protein 2 (HRP2) using whole blood eluted from dried blood spots. Results from 4 P falciparum infections from Rwanda (Pf) are compared with the Rwandan P vivax patient (R218) and a P vivax isolate obtained from an Indian patient (Pv+). Results are displayed as median fluorescence intensity minus background (MFI-bg) assay signal. (B) Capture of immunoglobulin (Ig)G from blood samples from 4 P falciparum-infected patients and the P vivax-infected patient R218 from the 2018 Rwandan therapeutic efficacy study (TES). Antigens used for IgG capture were merozoite surface protein 19 kD (MSP1) antigens from P falciparum, P malariae, P ovale spp, and P vivax. Data displayed as MFI-bg assay signal. (C) Agarose gel of nested polymerase chain reaction (PCR) products after amplification of DNA from the P vivax patient’s blood using P falciparum (Pf), P vivax (Pv), Plasmodium malariae (Pm), and Plasmodium ovale (Po) 18S primers compared with control DNA amplified with the same primers. Gel products in the box show the amplified P vivax DNA target. (D) Photo-induced electron transfer PCR (PET-PCR) amplification curves from DNA from the P vivax patient’s blood (R218) using P vivax 18S primers are shown in green squares. Controls presented include an Indian P vivax reference strain amplified using the same P vivax primers (blue triangles), the patient R218’s blood amplified using P falciparum primers (red diamonds), and a water nontemplate control amplified with P vivax primers (orange open circles). All PET-PCR curves are shown as the average of 3 replicates.