scholarly journals Multiple genetic origins of histidine-rich protein 2 gene deletion in Plasmodium falciparum parasites from Peru

2013 ◽  
Vol 3 (1) ◽  
Author(s):  
Sheila Akinyi ◽  
Tonya Hayden ◽  
Dionicia Gamboa ◽  
Katherine Torres ◽  
Jorge Bendezu ◽  
...  
Keyword(s):  
Plasmodium Falciparum ◽  
Gene Deletion ◽  
Genetic Origins

scholarly journals A Novel Tool for the Generation of Conditional Knockouts To Study Gene Function across the Plasmodium falciparum Life Cycle

mBio ◽  
2019 ◽  
Vol 10 (5) ◽  
Author(s):  
Marta Tibúrcio ◽  
Annie S. P. Yang ◽  
Kazuhide Yahata ◽  
Pablo Suárez-Cortés ◽  
Hugo Belda ◽  
...  
Keyword(s):  
Plasmodium Falciparum ◽  
Life Cycle ◽  
Genetic Modification ◽  
Gene Deletion ◽  
Genetically Modify ◽  
Complex Life Cycle ◽  
Mosquito Vector ◽  
Parasite Line ◽  
Content Type ◽  
First Time

ABSTRACT Plasmodium falciparum has a complex life cycle that involves interaction with multiple tissues inside the human and mosquito hosts. Identification of essential genes at all different stages of the P. falciparum life cycle is urgently required for clinical development of tools for malaria control and eradication. However, the study of P. falciparum is limited by the inability to genetically modify the parasite throughout its life cycle with the currently available genetic tools. Here, we describe the detailed characterization of a new marker-free P. falciparum parasite line that expresses rapamycin-inducible Cre recombinase across the full life cycle. Using this parasite line, we were able to conditionally delete the essential invasion ligand AMA1 in three different developmental stages for the first time. We further confirm efficient gene deletion by targeting the nonessential kinase FIKK7.1. IMPORTANCE One of the major limitations in studying P. falciparum is that so far only asexual stages are amenable to rapid conditional genetic modification. The most promising drug targets and vaccine candidates, however, have been refractory to genetic modification because they are essential during the blood stage or for transmission in the mosquito vector. This leaves a major gap in our understanding of parasite proteins in most life cycle stages and hinders genetic validation of drug and vaccine targets. Here, we describe a method that supports conditional gene deletion across the P. falciparum life cycle for the first time. We demonstrate its potential by deleting essential and nonessential genes at different parasite stages, which opens up completely new avenues for the study of malaria and drug development. It may also allow the realization of novel vaccination strategies using attenuated parasites.

scholarly journals Prevalence of pfhrp2 and/or pfhrp3 Gene Deletion in Plasmodium falciparum Population in Eight Highly Endemic States in India

PLoS ONE ◽  
2016 ◽  
Vol 11 (8) ◽  
pp. e0157949 ◽  
Author(s):  
Praveen Kumar Bharti ◽  
Himanshu Singh Chandel ◽  
Amreen Ahmad ◽  
Sri Krishna ◽  
Venkatachalam Udhayakumar ◽  
...  
Keyword(s):  
Plasmodium Falciparum ◽  
Gene Deletion ◽  
Falciparum Population

scholarly journals Diagnostic Performance of Hrp2 Based Diagnostic Test Kits and Frequency of Pfhrp2 Gene Deletion in Plasmodium falciparum Isolates of Osogbo, Southwestern Nigeria

2021 ◽  
pp. 20-25
Author(s):  
A. S. Nassar ◽  
A. S. Bakarey ◽  
A. A. Abdulazeez ◽  
O. O. Fayemi
Keyword(s):  
Plasmodium Falciparum ◽  
Diagnostic Test ◽  
Gene Deletion ◽  
False Negative ◽  
University Teaching ◽  
Pcr Analysis ◽  
Southwestern Nigeria ◽  
Blood Samples ◽  
Negative Results ◽  
Test Kit

Introduction: The introduction of P. falciparum encoded HRP-2 based malaria Rapid Diagnostic Test (RDT) kits is widely accepted in Nigeria and worldwide as a simplified form of diagnosis and a cheaper alternative to the microscopy technique (gold standard). However, deletion of Pfhrp2 gene contributes to false negative results and large number of such deletions has been reported in advanced countries thereby highlighting the importance of surveillance to detect such deletions in our local environment. Methodology: Microscopy as well as RDT techniques (using Rapid malaria test kit: SD BIOLINE Malaria Ag P.f/Pv, South Korea) were carried out on the blood samples of three hundred and twenty-three (323) febrile subjects attending Ladoke Akintola University Teaching Hospital, Osogbo, Osun State Nigeria. PCR analysis was also conducted on 50 blood samples that were positive for microscopy but negative for RDT. Results: The results from the study revealed that microscopy had a sensitivity of 99% and specificity of 99.2%. The RDT however had a sensitivity of 100% and a specificity of 60.1%. Fifty (50) samples that were positive for microscopy but negative for RDT were subjected to further PCR examination to detect the possible deletion of the Pfhrp-2 gene and the result revealed that the gene was present in 39 (78%) of the blood samples while remaining 11 (22%) samples lacked the gene which could possibly be the reason for the negative results obtained using the RDT kits. Conclusion: This study provides evidence of low level of presence of Pfhrp-2 gene deletion of Plasmodium falciparum parasites in our healthcare facility setting in Osogbo, Nigeria.

scholarly journals Investigation of HRPF2 Gene Deletion in Plasmodium Falciparum in Northwestern Nigeria

2021 ◽  
Vol 4 (1) ◽  
pp. 10-20
Author(s):  
Dayyabu Shehu ◽  
Farida Muhammad Aminu ◽  
Shehu Danlami ◽  
Jamila Ahmed Mashi
Keyword(s):  
Plasmodium Falciparum ◽  
Gene Deletion ◽  
False Negative ◽  
Malaria Diagnosis ◽  
Housekeeping Genes ◽  
Single Copy ◽  
Blood Film ◽  
Malaria Rapid Diagnostic Tests ◽  
Thick Blood Film ◽  
Strip Test

Abstract Malaria Rapid Diagnostic Tests (RDTs) plays an important role in malaria management and control. The Pf HRP2 based RDT kit is the most widely used RDT for malaria diagnosis in Nigeria but is affected by the deletion of HRP2 gene in Plasmodium falciparum parasites. Therefore, identifying the prevalence and distribution of Plasmodium falciparum parasites with deleted Pf HRP2 is important for malaria control. Pf HRP2 gene deletion was assessed in this study by first carrying out Giemsa stained thick blood film microscopy and Pf HRP2 RDT strip test. The samples were further analyzed for molecular examination by PCR assay for multiple single–copy genes (Pf Cox3, Pf HRP2, Pf HRP3 and Pf Beta tubulin). This study found the existence of eight (8) Plasmodium falciparum isolates lacking the HRP2 gene in the samples analyzed, this necessitates the need to develop a unique RDT Kit targeting other housekeeping genes unique for Plasmodium falciparum with far greater sensitivity than the current ones as to reduce the chances of false negative RDT result as well as developing unique RDT Kits targeting both PfHRP2 and PfHRP3 genes concomitantly in order to reduce the chances of having a false positive RDT results.

scholarly journals Plasmodium falciparum isolate with histidine-rich protein 2 gene deletion from Nyala City, Western Sudan

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Mohammed A. Boush ◽  
Moussa A. Djibrine ◽  
Ali Mussa ◽  
Mustafa Talib ◽  
A. Maki ◽  
...  
Keyword(s):  
Plasmodium Falciparum ◽  
Gene Deletion ◽  
Falciparum Isolate

Gene deletion from Plasmodium falciparum using FLP and Cre recombinases: Implications for applied site-specific recombination

2011 ◽  
Vol 41 (1) ◽  
pp. 117-123 ◽  
Author(s):  
Matthew T. O’Neill ◽  
Thuan Phuong ◽  
Julie Healer ◽  
Dave Richard ◽  
Alan F. Cowman
Keyword(s):  
Plasmodium Falciparum ◽  
Gene Deletion ◽  
Site Specific ◽  
Site Specific Recombination

scholarly journals Evaluation of Histidine-Rich Proteins 2 and 3 Gene Deletions in Plasmodium falciparum in Endemic Areas of the Brazilian Amazon

2020 ◽  
Vol 18 (1) ◽  
pp. 123
Author(s):  
Leandro Góes ◽  
Nathália Chamma-Siqueira ◽  
José Mário Peres ◽  
José Maria Nascimento ◽  
Suiane Valle ◽  
...  
Keyword(s):  
Plasmodium Falciparum ◽  
Gene Deletion ◽  
Brazilian Amazon ◽  
Amazon Region ◽  
The State ◽  
Molecular Surveillance ◽  
Gene Deletions ◽  
Exon 2 ◽  
Brazilian Amazon Region ◽  
Endemic Areas

Histidine-rich proteins 2 and 3 gene (pfhrp2 and pfhrp3) deletions affect the efficacy of rapid diagnostic tests (RDTs) based on the histidine-rich protein 2 (HRP2), compromising the correct identification of the Plasmodium falciparum species. Therefore, molecular surveillance is necessary for the investigation of the actual prevalence of this phenomenon and the extent of the disappearance of these genes in these areas and other South American countries, thus guiding national malaria control programs on the appropriate use of RDTs. This study aimed to evaluate the pfhrp2 and pfhrp3 gene deletion in P. falciparum in endemic areas of the Brazilian Amazon. Aliquots of DNA from the biorepository of the Laboratory of Basic Research in Malaria, Evandro Chagas Institute, with a positive diagnosis for P. falciparum infection as determined by microscopy and molecular assays, were included. Monoinfection was confirmed by nested-polymerase chain reaction assay, and DNA quality was assessed by amplification of the merozoite surface protein-2 gene (msp2). The pfhrp2 and pfhrp3 genes were amplified using primers for the region between exons 1 and 2 and for all extension of exon 2. Aliquots of DNA from 192 P. falciparum isolates were included in the study, with 68.7% (132/192) from the municipality of Cruzeiro do Sul (Acre) and 31.3% (60/192) from Manaus (Amazonas). Of this total, 82.8% (159/192) of the samples were considered of good quality. In the state of Acre, 71.7% (71/99) showed pfhrp2 gene deletion and 94.9% (94/99) showed pfhrp3 gene deletion, while in the state of Amazonas, 100.0% (60/60) of the samples showed pfhrp2 gene deletion and 98.3% (59/60) showed pfhrp3 gene deletion. Moreover, 79.8% (127/159) of isolates displayed gene deletion. Our findings confirm the presence of a parasite population with high frequencies of pfhrp2 and pfhrp3 gene deletions in the Brazilian Amazon region. This suggests reconsidering the use of HRP2-based RDTs in the Acre and Amazonas states and calls attention to the importance of molecular surveillance and mapping of pfhrp2/pfhrp3 deletions in this area and in other locations in the Amazon region to guarantee appropriate patient care, control and ultimately contribute to achieving P. falciparum malaria elimination.

scholarly journals A Comprehensive Analysis of the Genetic Diversity of Plasmodium falciparum Histidine-Rich Protein 2 (PfHRP2) in the Brazilian Amazon

2021 ◽  
Vol 11 ◽  
Author(s):  
Gabriel Luíz Costa ◽  
Maria Eduarda Pereira Mascarenhas ◽  
Thamires Oliveira Gasquez Martin ◽  
Laura Guimarães Fortini ◽  
Jaime Louzada ◽  
...  
Keyword(s):  
Plasmodium Falciparum ◽  
French Guiana ◽  
Gene Deletion ◽  
Point Of Care ◽  
Brazilian Amazon ◽  
Comprehensive Analysis ◽  
Conventional Pcr ◽  
Similar Sequence ◽  
Routine Diagnosis ◽  
Sequence Patterns

Early diagnosis and treatment are fundamental to the control and elimination of malaria. In many endemic areas, routine diagnosis is primarily performed microscopically, although rapid diagnostic tests (RDTs) provide a useful point-of-care tool. Most of the commercially available RDTs detect histidine-rich protein 2 (HRP2) of Plasmodium falciparum in the blood of infected individuals. Nonetheless, parasite isolates lacking the pfhrp2 gene are relatively frequent in some endemic regions, thereby hampering the diagnosis of malaria using HRP2-based RDTs. To track the efficacy of RDTs in areas of the Brazilian Amazon, we assessed pfhrp2 deletions in 132 P. falciparum samples collected from four malaria-endemic states in Brazil. Our findings show low to moderate levels of pfhrp2 deletion in different regions of the Brazilian Amazon. Overall, during the period covered by this study (2002-2020), we found that 10% of the P. falciparum isolates were characterized by a pfhrp2 deletion. Notably, however, the presence of pfhrp2-negative isolates has not been translated into a reduction in RDT efficacy, which in part may be explained by the presence of polyclonal infections. A further important finding was the discrepancy in the proportion of pfhrp2 deletions detected using two assessed protocols (conventional PCR versus nested PCR), which reinforces the need to perform a carefully planned laboratory workflow to assess gene deletion. This is the first study to perform a comprehensive analysis of PfHRP2 sequence diversity in Brazilian isolates of P. falciparum. We identified 10 PfHRP2 sequence patterns, which were found to be exclusive of each of the assessed regions. Despite the small number of PfHRP2 sequences available from South America, we found that the PfHRP2 sequences identified in Brazil and neighboring French Guiana show similar sequence patterns. Our findings highlight the importance of continuously monitoring the occurrence and spread of parasites with pfrhp2 deletions, while also taking into account the limitations of PCR-based testing methods associated with accuracy and the complexity of infections.

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