Antigen persistence of rapid diagnostic tests in pregnant women in Nanoro, Burkina Faso, and the implications for the diagnosis of malaria in pregnancy

Objectives To evaluate persistence of several Plasmodium antigens in pregnant women after treatment and compare diagnostics during treatment follow-up. Methods Thirty-two pregnant women (N = 32) with confirmed malaria infection by a histidine-rich protein 2 (HRP2)-based rapid diagnostic test (RDT) and microscopy were followed for 28 days after artemisinin-based combination therapy (ACT). A Plasmodium lactate dehydrogenase (pLDH)-based RDT and two ELISAs based on the detection of dihydrofolate reductase–thymidylate synthase (DHFR-TS) and haeme detoxification protein (HDP) were compared with each other and to RT-PCR at each visit. Results The mean visit number (95% confidence interval) on which the HRP2-based RDT was still positive after treatment was 3.4 (2.7–4.1) visits with some patients still positive at day 28. This is significantly later than the pLDH-based RDT [0.84 (0.55–1.1)], microscopy (median 1, range 1–3), DHFR-TS-ELISA [1.7 (1.1–2.3)] and RT-PCR (median 2, range 1–5) (P