Evaluation of Novel Bio credit Rapid Diagnostic Tests For Detection of Plasmodium Species, And Prevalence of Pfhrp2/3 Gene Deletions among Febrile Patients at Maksegnit Health Center, Northwest Ethiopia

Abstract

Background: Rapid diagnostic test (RDT) plays an essential role for prompt diagnosis of malaria in settings where using microscopy is not feasible. However, there is an increasing concern that Plasmodium falciparum histidine rich protein (PfHRP) gene deletions could impede the performance of the commonly used RDTs, resulting in a false negative diagnosis. This suggests the need to develop and evaluate new RDT kits to overcome such challenges. Objective: To evaluate the diagnostic performance of Biocredit RDTs Pf(pLDH/HRP2) and Pf/Pv(pLDH/pLDH) for detection of Plasmodium species and determine the prevalence of PfHRP 2/3 gene deletions among febrile patients at Maksegnit Health Center (MHC), northwest Ethiopia. Methods: A health facility-based cross-sectional study was conducted from September to December 2021 in 384 malaria suspected febrile study subjects at MHC. Finger-prick blood samples were collected for malaria diagnosis using microscopy, RDTs and Quantitative Polymerase Chain Reaction (qPCR). Sensitivity, specificity, positive and negative predictive values of the RDTs were determined by comparing with the gold standard microscopy and qPCR Digital Polymerase Chain Reaction (dPCR) was used to detect PfHRP 2/3 gene deletion. Results: The prevalence of malaria among febrile patients was 69.3%, 67.2%, 42.2% and 71.4% by microscopy, Biocredit RDT Pf/Pv (pLDH/pLDH), SD Bioline RDT and qPCR, respectively. By taking microscopy as a reference, the Biocredit Pf/Pv (pLDH/pLDH) RDT had sensitivity and specificity of 97.9% and 97.4% for P. falciparum and 94.5% and 97.5% for P. vivax, respectively. The Biocredit Pf (pLDH/HRP2) RDT had sensitivity and specificity of 97.4% and 97.5%. In contrast, SD Bioline RDT had sensitivity and specificity of 51.3% and 93.2% for P. falciparum, and 86.3% and 96.5% for P. vivax, respectively. By taking qPCR as a reference, the sensitivity and specificity of Biocredit Pf/Pv (pLDH/pLDH) were 95.5% and 96.4% for P. falciparum, and 90.8% and 99.1% for P. vivax, respectively. The Biocredit Pf (pLDH/pHRP2) RDT had sensitivity and specificity of 94.9% and 97.4%, respectively, whereas the SD Bioline RDT had sensitivity and specificity of 50.0% and 96.5% for P. falciparum, and 83.0% and 96.5% for P. vivax, respectively. Out of 99 SD Bioline RDT negative samples, Pfhrp2 and Pfhrp3 exon 2 gene deletions were observed in 23.2% (46/198) and 27.7% (55/198) of the PCR-positive samples, II respectively. Double deletions in pfhrp2 and pfhrp3 were detected in 13.1% (26/198) of the PCR positive samples. Conclusion: The sensitivity and specificity of Biochredit RDTs kits documented in this study comply with the WHO limit of detection for routine diagnosis of clinical malaria, with more reliable diagnostic performance compared to the conventional (SD Bioline) RDT. This study confirms the presence of 13.1% of pfhrp2/3 gene deletions So, we should consider alternative diagnostic tool like Pf-pLDH in the study area. Further nationwide survey on the prevalence of hrp 2/3 gene deletion is crucial.