Background Histidine Rich Protein 2-based rapid diagnostic tests(HRP2-based RDTs)are widely used for malaria diagnosis in Malawi,but their accuracy may be compromised by Plasmodium falciparum parasites lacking the P.f...Background Histidine Rich Protein 2-based rapid diagnostic tests(HRP2-based RDTs)are widely used for malaria diagnosis in Malawi,but their accuracy may be compromised by Plasmodium falciparum parasites lacking the P.falciparum histidine rich protein 2(pfhrp2)and P.falciparum histidine rich protein 3(pfhrp3)genes.While such deletions have been reported in other malaria-endemic countries,their presence and diagnostic impact in Malawi remain unknown.This study aimed to determine the prevalence of pfhrp2/pfhrp3 gene deletions in Malawi and their effect on the diagnostic accuracy of HRP2-based RDTs relative to light microscopy and qPCR.Methods A cross-sectional study was conducted between December 2020 and June 2021,enrolling 1582 participants from referral hospitals in Mzuzu(n=1186)and Lilongwe(n=396).Malaria diagnosis was performed using RDTs,microscopy,and qPCR.A total of 391 P.falciparum positive samples were analyzed for pfhrp2/pfhrp3 gene deletions using multiplex qPCR.Diagnostic accuracy metrics,such as sensitivity and specificity,were calculated with 95%confidence intervals.Spearman correlation was applied to assess associations involving log-transformed parasitemia,unpaired t-tests were used to compare diagnostic methods,and Mann–Whitney tests were used to compare symptomatic and asymptomatic groups.Results Malaria prevalence was higher in Lilongwe(45.2%)than in Mzuzu(22.9%).Infections in Lilongwe were predominantly asymptomatic(94.2%),whereas Mzuzu had mostly symptomatic cases(97.1%)(P<0.0002).RDTs demonstrated higher sensitivity of 78.5%(95%CI:74.6–82.1%)than microscopy 64.8%(95%CI:60.3–69.1),but slightly lower specificity,with 93.6%(95%CI:92.0–95.0%)for RDT compared to 95.4%(95%CI:94.0–96.6%)for microscopy.Dual pfhrp2/3 gene deletions were found in 24(15.0%)isolates from Lilongwe and 24(10.4%)from Mzuzu.All dual-deleted samples were false negative by RDT but were positive by microscopy and qPCR.Conclusions This study is the first to report pfhrp2/3 gene deletions in Malawi.The presence of these deletions may compromise the performance of HRP2-based RDTs,indicating the need to reassess diagnostic strategies in affected regions.展开更多
基金supported by the Korea Health Technology R&D Project through the Korea Health Industry Development Institute(KHIDI)funded by the Ministry of Health&Welfare(HI22C0820&RS-2025-02309009)+1 种基金the National Research Foundation of Korea(NRF)funded by the Ministry of Education(RS-2023-00240627)the Regional Innovation System&Education(RISE)program through the Gangwon RISE Center,funded by the Ministry of Education(MoE)and Gangwon State(G.S.),Republic of Korea(2025-RISE-10-002)(J-H.H.).
文摘Background Histidine Rich Protein 2-based rapid diagnostic tests(HRP2-based RDTs)are widely used for malaria diagnosis in Malawi,but their accuracy may be compromised by Plasmodium falciparum parasites lacking the P.falciparum histidine rich protein 2(pfhrp2)and P.falciparum histidine rich protein 3(pfhrp3)genes.While such deletions have been reported in other malaria-endemic countries,their presence and diagnostic impact in Malawi remain unknown.This study aimed to determine the prevalence of pfhrp2/pfhrp3 gene deletions in Malawi and their effect on the diagnostic accuracy of HRP2-based RDTs relative to light microscopy and qPCR.Methods A cross-sectional study was conducted between December 2020 and June 2021,enrolling 1582 participants from referral hospitals in Mzuzu(n=1186)and Lilongwe(n=396).Malaria diagnosis was performed using RDTs,microscopy,and qPCR.A total of 391 P.falciparum positive samples were analyzed for pfhrp2/pfhrp3 gene deletions using multiplex qPCR.Diagnostic accuracy metrics,such as sensitivity and specificity,were calculated with 95%confidence intervals.Spearman correlation was applied to assess associations involving log-transformed parasitemia,unpaired t-tests were used to compare diagnostic methods,and Mann–Whitney tests were used to compare symptomatic and asymptomatic groups.Results Malaria prevalence was higher in Lilongwe(45.2%)than in Mzuzu(22.9%).Infections in Lilongwe were predominantly asymptomatic(94.2%),whereas Mzuzu had mostly symptomatic cases(97.1%)(P<0.0002).RDTs demonstrated higher sensitivity of 78.5%(95%CI:74.6–82.1%)than microscopy 64.8%(95%CI:60.3–69.1),but slightly lower specificity,with 93.6%(95%CI:92.0–95.0%)for RDT compared to 95.4%(95%CI:94.0–96.6%)for microscopy.Dual pfhrp2/3 gene deletions were found in 24(15.0%)isolates from Lilongwe and 24(10.4%)from Mzuzu.All dual-deleted samples were false negative by RDT but were positive by microscopy and qPCR.Conclusions This study is the first to report pfhrp2/3 gene deletions in Malawi.The presence of these deletions may compromise the performance of HRP2-based RDTs,indicating the need to reassess diagnostic strategies in affected regions.
