Plasmodium falciparum pfhrp2 and pfhrp3 Gene Deletions in Malaria-Hyperendemic Region, South Sudan.
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ABSTRACT:
SUBMITTER: Molina-de la Fuente I
PROVIDER: S-EPMC9796199 | biostudies-literature | 2023 Jan
REPOSITORIES: biostudies-literature
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Plasmodium falciparum pfhrp2 and pfhrp3 Gene Deletions in Malaria-Hyperendemic Region, South Sudan.
Molina-de la Fuente Irene I Benito María José Sagrado MJS Flevaud Laurence L Ousley Janet J Pasquale Harriet Akello HA Julla Ahmed A Abdi Abdirashid M AM Chol Buai Tut BT Abubakr Bakri B Benito Agustín A Casademont Cristian C Nanclares Carolina C Berzosa Pedro P
Emerging infectious diseases 20230101 1
Pfhrp2 and pfhrp3 gene deletions threaten the use of Plasmodium falciparum malaria rapid diagnostic tests globally. In South Sudan, deletion frequencies were 15.6% for pfhrp2, 20.0% for pfhrp3, and 7.5% for double deletions. Deletions were approximately twice as prevalent in monoclonal infections than in polyclonal infections. ...[more]
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Project description:Malaria rapid diagnostic tests (RDTs) targeting the Plasmodium falciparum histidine-rich protein 2 (PfHRP2) are widely used to diagnose P. falciparum infection. However, reports of P. falciparum strains lacking PfHRP2 and the structurally similar PfHRP3 have raised concerns about the utility and reliability of PfHRP2-based RDTs. This study investigated the presence of P. falciparum with pfhrp2 and/or pfhrp3 gene deletions among infected residents in the Lake Victoria region, Kenya. Four cross-sectional malaria, surveys were conducted in four sites (Suba South, Mfangano, Kibuogi, and Ngodhe) from September 2018 to January 2020. P. falciparum infections were detected using a PfHRP2-based RDT, microscopy, and PCR on 9120 finger-prick blood samples. Samples negative by RDT but positive by PCR were selected for PCR amplification of pfmsp1 and pfmsp2 to confirm the quality and quantity of P. falciparum DNA. Samples positive for both pfmsp1 and pfmsp2 were included for detection of deletions of exons 1 and 2 in pfhrp2 and pfhrp3 PCR. The multiplicity of infection (MOI) was determined as the higher allele count between pfmsp1 and pfmsp2. Logistic regression analysis was performed to analyze the association between pfhrp2 and/or pfhrp3 deletions and demographic and infection variables. Of the 445 RDT-negative and PCR-positive samples, 125 (28.1%) were analyzed for pfhrp2 and pfhrp3 deletions. Single pfhrp2 deletion, single pfhrp3 deletion, and pfhrp2/3 double deletions were detected in 13 (10.4%), 19 (15.2%), and 36 (28.8%) samples, respectively. Single pfhrp2 deletion was found in all sites while single pfhrp3 deletion was found in all sites except Kibuogi. The majority of samples with pfhrp2 and/or pfhrp3 deletions were submicroscopic (73.5%), asymptomatic (80.9%), and monoclonal (80.9%). Polyclonal infection was significantly (p = 0.022) associated with a lower odds of pfhrp2/3 double deletion, suggesting detection of intact pfhrp2/3 in mixed infections. We report the presence of P. falciparum with pfhrp2/pfhrp3 double deletions among asymptomatic and submicroscopic infections in Kenya. Our findings highlight the need for active monitoring of pfhrp2 and pfhrp3 deletions at the community level to improve malaria detection and control in the region.
| S-EPMC11653864 | biostudies-literature
Project description:BackgroundMalaria rapid diagnostic tests (RDTs) remain the main point-of-care tests for diagnosis of symptomatic Plasmodium falciparum malaria in endemic areas. However, parasites with gene deletions in the most common RDT target, histidine rich protein 2 (pfhrp2/HRP2), can produce false-negative RDT results leading to inadequate case management. The objective of this study was to determine the prevalence of hrp2/3 deletions causing false-negative RDT results in Vietnam (Gia Lai and Dak Lak provinces).MethodsIndividuals presenting with malaria symptoms at health facilities were screened for P. falciparum infection using light microscopy and HRP2-RDT (SD Bioline Malaria Antigen Pf/Pv RDT, Abbott). Microscopically confirmed P. falciparum infections were analysed for parasite species by 18S rRNA qPCR, and pfhrp2 and pfhrp3 exon2 deletions were investigated by nested PCR. pfhrp2 amplicons were sequenced by the Sanger method and HRP2 plasma levels were determined by enzyme-linked immunosorbent assay (ELISA).ResultsThe prevalence of false-negative RDT results among symptomatic cases was 5.6% (15/270). No pfhrp2 and pfhrp3 deletions were identified. False-negative RDT results were associated with lower parasite density (p = 0.005) and lower HRP2 plasma concentrations (p < 0.001), as compared to positive RDT.ConclusionsThe absence of hrp2/3 deletions detected in this survey suggests that HRP2-based malaria RDTs remain effective for the diagnosis of symptomatic P. falciparum malaria in Central Vietnam.
| S-EPMC9724378 | biostudies-literature
Project description:Histidine-rich protein 2 (HRP2)-based rapid diagnostic tests detect Plasmodium falciparum malaria and are used throughout sub-Saharan Africa. However, deletions in the pfhrp2 and related pfhrp3 (pfhrp2/3) genes threaten use of these tests. Therapeutic efficacy studies (TESs) enroll persons with symptomatic P. falciparum infection. We screened TES samples collected during 2016-2018 in Ethiopia, Kenya, Rwanda, and Madagascar for HRP2/3, pan-Plasmodium lactate dehydrogenase, and pan-Plasmodium aldolase antigen levels and selected samples with low levels of HRP2/3 for pfhrp2/3 genotyping. We observed deletion of pfhrp3 in samples from all countries except Kenya. Single-gene deletions in pfhrp2 were observed in 1.4% (95% CI 0.2%-4.8%) of Ethiopia samples and in 0.6% (95% CI 0.2%-1.6%) of Madagascar samples, and dual pfhrp2/3 deletions were noted in 2.0% (95% CI 0.4%-5.9%) of Ethiopia samples. Although this study was not powered for precise prevalence estimates, evaluating TES samples revealed a low prevalence of pfhrp2/3 deletions in most sites.
| S-EPMC8888236 | biostudies-literature
Project description:BackgroundDeletion of pfhrp2 and/or pfhrp3 genes cause false negatives in malaria rapid diagnostic test (RDT) and threating malaria control strategies. This systematic review aims to assess the main methodological aspects in the study of pfhrp2 and pfhrp3 gene deletions and its global epidemiological status, with special focus on their distribution in Africa; and its possible impact in RDT.MethodsThe systematic review was conducted by examining the principal issues of study design and methodological workflow of studies addressing pfhrp2 deletion. Meta-analysis was applied to represent reported prevalences of pfhrp2 and pfhrp3 single and double deletion in the World Health Organization (WHO) region. Pooled-prevalence of deletions was calculated using DerSimonnian-Laird random effect model. Then, in-deep analysis focused on Africa was performed to assess possible variables related with these deletions. Finally, the impact of these deletions in RDT results was analysed combining reported information about RDT sensitivity and deletion prevalences.Results49 articles were included for the systematic review and 37 for the meta-analysis, 13 of them placed in Africa. Study design differs significantly, especially in terms of population sample and information reported, resulting in high heterogeneity between studies that difficulties comparisons and merged conclusions. Reported prevalences vary widely in all the WHO regions, significantly higher deletion were reported in South-Central America, following by Africa and Asia. Pfhrp3 deletion is more prevalent (43% in South-Central America; 3% in Africa; and 1% in Asia) than pfhrp2 deletion (18% in South-Central America; 4% in Africa; and 3% in Asia) worldwide. In Africa, there were not found differences in deletion prevalence by geographical or population origin of samples. The prevalence of deletion among false negatives ranged from 0 to 100% in Africa, but in Asia and South-Central America was only up to 90% and 48%, respectively, showing substantial relation between deletions and false negatives.ConclusionThe concerning prevalence of pfhrp2, pfhrp3 and pfhrp2/3 gene deletions, as its possible implications in malaria control, highlights the importance of regular and systematic surveillance of these deletions. This review has also outlined that a standardized methodology could play a key role to ensure comparability between studies to get global conclusions.
| S-EPMC8220794 | biostudies-literature
Project description:BackgroundMalaria remains a public health problem in some countries of Central America. Rapid diagnostic tests (RDTs) are one of the most useful tools to assist in the diagnosis of malaria in remote areas. Since its introduction, a wide variety of RDTs have been developed for the detection of different parasite antigens. PfHRP2 is the most targeted antigen for the detection of Plasmodium falciparum infections. Genetic mutations and gene deletions are important factors influencing or affecting the performance of rapid diagnostic tests.MethodsIn order to demonstrate the presence or absence of the pfhrp2 and pfhrp3 genes and their flanking regions, a total of 128 blood samples from patients with P. falciparum infection from three Central American countries were analysed through nested or semi-nested PCR approaches.ResultsIn total, 25.8 and 91.4% of the isolates lacked the region located between exon 1 and exon 2 of pfhrp2 and pfhrp3 genes, respectively. Parasites from the three countries showed deletions of one or both genes. The highest proportion of pfhrp2 deletions was found in Nicaragua while the isolates from Guatemala revealed the lowest number of pfhrp2 deletions. Parasites collected from Honduras showed the highest proportion of phfrp3 absence (96.2%). Twenty-one percent of isolates were double negative mutants for the exon 1-2 segment of both genes, and 6.3% of isolates lacked the full-length coding region of both genes.ConclusionsThis study provides molecular evidence of the existence of P. falciparum isolates lacking the pfhrp2 and pfhrp3 genes, and their flanking regions, in Honduras, Guatemala and Nicaragua. This finding could hinder progress in the control and elimination of malaria in Central America. Continuous evaluation of RDTs and molecular surveillance would be recommended.
| S-EPMC6119307 | biostudies-literature
Project description:Deletions of pfhrp2 and paralogue pfhrp3 (pfhrp2/3) genes threaten Plasmodium falciparum diagnosis by rapid diagnostic test. We examined 1,002 samples from suspected malaria patients in Djibouti City, Djibouti, to investigate pfhrp2/3 deletions. We performed assays for Plasmodium antigen carriage, pfhrp2/3 genotyping, and sequencing for 7 neutral microsatellites to assess relatedness. By PCR assay, 311 (31.0%) samples tested positive for P. falciparum infection, and 296 (95.2%) were successfully genotyped; 37 (12.5%) samples were pfhrp2+/pfhrp3+, 51 (17.2%) were pfhrp2+/pfhrp3-, 5 (1.7%) were pfhrp2-/pfhrp3+, and 203 (68.6%) were pfhrp2-/pfhrp3-. Histidine-rich protein 2/3 antigen concentrations were reduced with corresponding gene deletions. Djibouti P. falciparum is closely related to Ethiopia and Eritrea parasites (pairwise GST 0.68 [Ethiopia] and 0.77 [Eritrea]). P. falciparum with deletions in pfhrp2/3 genes were highly prevalent in Djibouti City in 2019-2020; they appear to have arisen de novo within the Horn of Africa and have not been imported.
| S-EPMC9514350 | biostudies-literature
Project description:Rapid diagnostic tests (RDTs) detecting histidine-rich protein 2 (HRP2) and HRP3 are widely used throughout sub-Saharan Africa (SSA) to diagnose Plasmodium falciparum malaria. However, multiple SSA countries have reported pfhrp2 and pfhrp3 (pfhrp2/3) gene deletions. Blood samples (n = 1109) collected from patients with P. falciparum infection from six health facilities throughout the Democratic Republic of the Congo (DRC) from March 2017 to January 2018 were evaluated for pfhrp2/3 deletions. Samples were assayed for HRP2, pan-Plasmodium LDH (pLDH) and aldolase (pAldolase) antigens by bead-based multiplex antigen assay. Samples with low HRP2 concentration compared to pLDH and pAldolase antigens were selected for further pfhrp2/3 genotyping PCRs. The majority of blood samples (93.3%, 1035/1109) had high concentrations of the HRP2 antigen. Single deletions of pfhrp2 were identified in 0.27% (3/1109) of screened samples, with one sample from each of the Kapolowe, Mikalayi, and Rutshuru study sites. A pfhrp3 single deletion (0.09%, 1/1109) was found in the Kapolowe site. Dual pfhrp2 and pfhrp3 deletions were not observed. Due to, the low numbers of pfhrp2 deletions and the sporadic locations of these deletions, the use of HRP2-based RDTs appears to still be appropriate for these locations in DRC.
| S-EPMC8626453 | biostudies-literature
Project description:BackgroundHistidine-rich protein 2 (HRP2)-based malaria rapid diagnostic tests (RDTs) are effective and widely used for the detection of wild-type Plasmodium falciparum infections. Although recent studies have reported false negative HRP2 RDT results due to pfhrp2 and pfhrp3 gene deletions in different countries, there is a paucity of data on the deletions of these genes in Tanzania.MethodsA community-based cross-sectional survey was conducted between July and November 2017 in four regions: Geita, Kigoma, Mtwara and Ruvuma. All participants had microscopy and RDT performed in the field and provided a blood sample for laboratory multiplex antigen detection (for Plasmodium lactate dehydrogenase, aldolase, and P. falciparum HRP2). Samples showing RDT false negativity or aberrant relationship of HRP2 to pan-Plasmodium antigens were genotyped to detect the presence/absence of pfhrp2/3 genes.ResultsOf all samples screened by the multiplex antigen assay (n = 7543), 2417 (32.0%) were positive for any Plasmodium antigens while 5126 (68.0%) were negative for all antigens. The vast majority of the antigen positive samples contained HRP2 (2411, 99.8%), but 6 (0.2%) had only pLDH and/or aldolase without HRP2. Overall, 13 samples had an atypical relationship between a pan-Plasmodium antigen and HRP2, but were positive by PCR. An additional 16 samples with negative HRP2 RDT results but P. falciparum positive by microscopy were also chosen for pfhrp2/3 genotyping. The summation of false negative RDT results and laboratory antigen results provided 35 total samples with confirmed P. falciparum DNA for pfhrp2/3 genotyping. Of the 35 samples, 4 (11.4%) failed to consistently amplify positive control genes; pfmsp1 and pfmsp2 and were excluded from the analysis. The pfhrp2 and pfhrp3 genes were successfully amplified in the remaining 31 (88.6%) samples, confirming an absence of deletions in these genes.ConclusionsThis study provides evidence that P. falciparum parasites in the study area have no deletions of both pfhrp2 and pfhrp3 genes. Although single gene deletions could have been missed by the multiplex antigen assay, the findings support the continued use of HRP2-based RDTs in Tanzania for routine malaria diagnosis. There is a need for the surveillance to monitor the status of pfhrp2 and/or pfhrp3 deletions in the future.
| S-EPMC7640459 | biostudies-literature
Project description:Guyana and Suriname have made important progress in reducing the burden of malaria. While both countries use microscopy as the primary tool for clinical diagnosis, malaria rapid diagnostic tests (RDTs) are useful in remote areas of the interior where laboratory support may be limited or unavailable. Recent reports indicate that histidine-rich protein 2 (PfHRP2)-based diagnostic tests specific for detection of P. falciparum may provide false negative results in some parts of South America due to the emergence of P. falciparum parasites that lack the pfhrp2 gene, and thus produce no PfHRP2 antigen. Pfhrp2 and pfhrp3 genes were amplified in parasite isolates collected from Guyana and Suriname to determine if there were circulating isolates with deletions in these genes. Pfhrp3 deletions were monitored because some monoclonal antibodies utilized in PfHRP2-based RDTs cross-react with the PfHRP3 protein. We found that all 97 isolates from Guyana that met the inclusion criteria were both pfhrp2- and pfhrp3-positive. In Suriname (N = 78), 14% of the samples tested were pfhrp2-negative while 4% were pfhrp3-negative. Furthermore, analysis of the genomic region proximal to pfhrp2 and pfhrp3 revealed that genomic deletions extended to the flanking genes. We also investigated the population substructure of the isolates collected to determine if the parasites that had deletions of pfhrp2 and pfhrp3 belonged to any genetic subtypes. Cluster analysis revealed that there was no predominant P. falciparum population substructure among the isolates from either country, an indication of genetic admixture among the parasite populations. Furthermore, the pfhrp2-deleted parasites from Suriname did not appear to share a single, unique genetic background.
| S-EPMC4433255 | biostudies-literature
Project description:BACKGROUND:Rapid diagnostic tests (RDTs) that detect histidine-rich protein 2 (PfHRP2) are used throughout Africa for the diagnosis of Plasmodium falciparum malaria. However, recent reports indicate that parasites lacking the pfhrp2 and/or histidine-rich protein 3 (pfhrp3) genes, which produce antigens detected by these RDTs, are common in select regions of South America, Asia, and Africa. Proving the absence of a gene is challenging, and multiple PCR assays targeting these genes have been described. A detailed characterization and comparison of published assays is needed to facilitate robust and streamlined testing approaches. RESULTS:Among six pfhrp2 and pfhrp3 PCR assays tested, the lower limit of detection ranged from 0.01 pg/µL to 0.1 ng/µL of P. falciparum 3D7 strain DNA, or approximately 0.4-4000 parasite genomes/µL. By lowering the elongation temperature to 60 °C, a tenfold improvement in the limit of detection and/or darker bands for all exon 1 targets and for the first-round reaction of a single exon 2 target was achieved. Additionally, assays targeting exon 1 of either gene yielded spurious amplification of the paralogous gene. Using these data, an optimized testing algorithm for the detection of pfhrp2- and pfhrp3-negative P. falciparum is proposed. CONCLUSIONS:Surveillance of pfhrp2- and pfhrp3-negative P. falciparum requires careful laboratory workflows. PCR-based testing methods coupled with microscopy and/or antigen testing serve as useful tools to support policy development. Standardized approaches to the detection of pfhrp2- and pfhrp3-negative P. falciparum should inform efforts to define the impact of these parasites.
| S-EPMC5879555 | biostudies-literature