scholarly journals Community-based surveys for Plasmodium falciparum pfhrp2 and pfhrp3 gene deletions in selected regions of mainland Tanzania

2020 ◽  
Vol 19 (1) ◽  
Author(s):  
Catherine Bakari ◽  
Sophie Jones ◽  
Gireesh Subramaniam ◽  
Celine I. Mandara ◽  
Mercy G. Chiduo ◽  
...  
Keyword(s):  
Plasmodium Falciparum ◽  
Single Gene ◽  
False Negative ◽  
Malaria Diagnosis ◽  
Positive Control ◽  
Cross Sectional Survey ◽  
Community Based ◽  
Cross Sectional ◽  
Gene Deletions ◽  
Antigen Assay

Abstract Background Histidine-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. Methods A 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. Results Of 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. Conclusions This 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.

scholarly journals Detection of high prevalence of Plasmodium falciparum histidine-rich protein 2/3 gene deletions in Assosa zone, Ethiopia: implication for malaria diagnosis

2021 ◽  
Vol 20 (1) ◽  
Author(s):  
Gezahegn Solomon Alemayehu ◽  
Kayla Blackburn ◽  
Karen Lopez ◽  
Cheikh Cambel Dieng ◽  
Eugenia Lo ◽  
...  
Keyword(s):  
Plasmodium Falciparum ◽  
Parasite Density ◽  
False Negative ◽  
Malaria Diagnosis ◽  
Dried Blood Spots ◽  
Northwest Ethiopia ◽  
Cross Sectional ◽  
Gene Deletions ◽  
Exon 2 ◽  
Flanking Regions

Abstract Background Rapid diagnostic tests (RDTs) targeting histidine rich protein 2(HRP2) are widely used for diagnosis of Plasmodium falciparum infections. Besides PfHRP2, the PfHRP3 antigen contributes to the detection of P. falciparum infections in PfHRP2 RDTs. However, the performance HRP2-based RDT is affected by pfhrp2/3 gene deletions resulting in false-negative test results. The objective of this study was to determine the presence and prevalence of pfhrp2/3 gene deletions including the respective flanking regions among symptomatic patients in Assosa zone, Northwest Ethiopia. Methods A health-facility based cross-sectional study was conducted in febrile patients seeking a malaria diagnosis in 2018. Blood samples were collected by finger-prick for microscopic examination of blood smears, malaria RDT, and molecular analysis using dried blood spots (DBS) prepared on Whatman filter paper. A total of 218 P. falciparum positive samples confirmed by quantitative PCR were included for molecular assay of pfhrp2/3 target gene. Results Of 218 P. falciparum positive samples, exon 2 deletions were observed in 17.9% of pfhrp2 gene and in 9.2% of pfhrp3 gene. A high proportion of deletions in short segments of pfhrp2 exon1-2 (50%) was also detected while the deletions of the pfhrp3 exon1-2 gene were 4.1%. The deletions were extended to the downstream and upstream of the flanking regions in pfhrp2/3 gene (above 30%). Of eighty-six PfHRP2 RDT negative samples, thirty-six lacked pfhrp2 exon 2. Five PfHRP2 RDT negative samples had double deletions in pfhrp2 exon 2 and pfhrp3 exon2. Of these double deletions, only two of the samples with a parasite density above 2000 parasite/µl were positive by the microscopy. Three samples with intact pfhrp3 exon2 in the pfhrp2 exon2 deleted parasite isolates were found to be positive by PfHRP2 RDT and microscopy with a parasite density above 10,000/µl. Conclusion This study confirms the presence of deletions of pfhrp2/3 gene including the flanking regions. Pfhrp2/3 gene deletions results in false-negative results undoubtedly affect the current malaria control and elimination effort in the country. However, further countrywide investigations are required to determine the magnitude of pfhrp2/3 gene deletions and its consequences on routine malaria diagnosis.

scholarly journals Community-based surveys for Plasmodium falciparum pfhrp2 and pfhrp3 gene deletions in selected regions of mainland Tanzania

2020 ◽  
Author(s):  
Catherine Bakari ◽  
Sophie Jones ◽  
Gireesh Subramaniam ◽  
Celine Isaack Mandara ◽  
Mercy G Chiduo ◽  
...  
Keyword(s):  
Plasmodium Falciparum ◽  
False Negative ◽  
Malaria Diagnosis ◽  
Positive Control ◽  
Gene Deletions ◽  
Negative Results ◽  
False Negative Results ◽  
Malaria Rapid Diagnostic Tests ◽  
The Status ◽  
Relationship Of

Background: Despite recent reports of false negative results among histidine-rich protein 2 (HRP2) based-malaria rapid diagnostic tests (mRDTs) caused by pfhrp2/3 gene deletions in different countries, there is paucity of data in Tanzania. Methods: This study assessed the status of pfhrp2/3 deletions in 7,543 blood sample using laboratory multiplex antigen detection (Plasmodium lactate dehydrogenase - pLDH, aldolase, and HRP2). Samples showing mRDT false negativity or aberrant relationship of HRP2 to pan-Plasmodium antigens were genotyped for pfhrp2/3 genes. Results: Of all samples, 2,417 (32.0%) were positive for any Plasmodium antigens while 5,126 (68.0%) were negative. About 99.8% (n=2,411) of antigen positive samples had HRP2, but 6 (0.2%) had only pLDH and/or pAldolase. Thirteen samples had atypical relationships between pan-Plasmodium antigens and HRP2, but were positive by PCR. An additional 16 samples with negative HRP2 mRDTs but positive by microscopy were also chosen; all giving 35 samples genotyped for pfhrp2/3. Of 35 samples, 4 (11.4%) failed to consistently amplify positive control genes (pfmsp1 and pfmsp2), and pfhrp2 and pfhrp3 genes were successfully amplified in 31 (88.6%) samples. Conclusions: Lack of pfhrp2 and/or pfhrp3 genes deletions in Plasmodium falciparum parasites supports continued use of HRP2-based mRDTs for routine malaria diagnosis in Tanzania.

scholarly journals No evidence of false-negative Plasmodium falciparum rapid diagnostic results in Monrovia, Liberia

2021 ◽  
Vol 20 (1) ◽  
Author(s):  
Mandella King ◽  
Alexander E. George ◽  
Pau Cisteró ◽  
Christine K. Tarr-Attia ◽  
Beatriz Arregui ◽  
...  
Keyword(s):  
Plasmodium Falciparum ◽  
False Negative ◽  
Malaria Diagnosis ◽  
Rapid Diagnostic Tests ◽  
Molecular Testing ◽  
False Negatives ◽  
Gene Deletions ◽  
History Of ◽  
Catholic Hospital ◽  
Or History

Abstract Background Malaria diagnosis in many malaria-endemic countries relies mainly on the use of rapid diagnostic tests (RDTs). The majority of commercial RDTs used in Africa detect the Plasmodium falciparum histidine-rich protein 2 (PfHRP2). pfhrp2/3 gene deletions can therefore lead to false-negative RDT results. This study aimed to evaluate the frequency of PCR-confirmed, false-negative P. falciparum RDT results in Monrovia, Liberia. Methods PfHRP2-based RDT (Paracheck Pf®) and microscopy results from 1038 individuals with fever or history of fever (n = 951) and pregnant women at first antenatal care (ANC) visit (n = 87) enrolled in the Saint Joseph’s Catholic Hospital (Monrovia) from March to July 2019 were used to assess the frequency of false-negative RDT results. True–false negatives were confirmed by detecting the presence of P. falciparum DNA by quantitative PCR in samples from individuals with discrepant RDT and microscopy results. Samples that were positive by 18S rRNA qPCR but negative by PfHRP2-RDT were subjected to multiplex qPCR assay for detection of pfhrp2 and pfhrp3. Results One-hundred and eighty-six (19.6%) and 200 (21.0%) of the 951 febrile participants had a P. falciparum-positive result by RDT and microscopy, respectively. Positivity rate increased with age and the reporting of joint pain, chills and shivers, vomiting and weakness, and decreased with the presence of coughs and nausea. The positivity rate at first ANC visit was 5.7% (n = 5) and 8% (n = 7) by RDT and microscopy, respectively. Out of 207 Plasmodium infections detected by microscopy, 22 (11%) were negative by RDT. qPCR confirmed absence of P. falciparum DNA in the 16 RDT-negative but microscopy-positive samples which were available for molecular testing. Among the 14 samples that were positive by qPCR but negative by RDT and microscopy, 3 only amplified pfldh, and among these 3 all were positive for pfhrp2 and pfhrp3. Conclusion There is no qPCR-confirmed evidence of false-negative RDT results due to pfhrp2/pfhrp3 deletions in this study conducted in Monrovia (Liberia). This indicates that these deletions are not expected to affect the performance of PfHRP2-based RDTs for the diagnosis of malaria in Liberia. Nevertheless, active surveillance for the emergence of PfHRP2 deletions is required.

scholarly journals Prevalence of plasmodium, leptospira and rickettsia species in Northern Tanzania: a community based survey

2020 ◽  
Vol 20 (1) ◽  
pp. 199-207
Author(s):  
Jaffu O Chilongola ◽  
Elias J Sabuni ◽  
Eliakimu Paul Kapyolo
Keyword(s):  
Infectious Diseases ◽  
Malaria Diagnosis ◽  
Plasmodium Infection ◽  
Cross Sectional Survey ◽  
Community Based ◽  
Cross Sectional ◽  
Rickettsia Species ◽  
Northern Tanzania ◽  
Leptospira Spp ◽  
Study Sites

Background: The overlap of symptoms, geographic and seasonal co-occurrence of Plasmodium, Leptospira and Rickettsia infections makes malaria diagnosis difficult, increasing the chances of misdiagnosis. The paucity of data on the prevalence Plasmodium, Leptospira and Rickettsia infections contributes to an overly diagnosis of malaria. We aimed to determine the prevalence and distribution of Plasmodium, Leptospira and Rickettsia infections in northern Tanzania. Methods: A community based, cross sectional survey was conducted in two sites in Northern Tanzania. PCR was used to detect Plasmodium, Leptospira and Rickettsia infections. Results: The prevalence of P. falciparum and Leptospira spp were 31/128 (24.2%) and 3/128 (2.3%), respectively. No Rickettsia infection was detected in any of the two sites. Taking study sites separately, Plasmodium infection was detected in 31/63(49.2%) of participants in Bondo while Leptospira infection was detected in 3/65(4.6%) of participants in Magugu. Plasmodium was not detected in Magugu while no Leptospira infections were detected in Bondo. Fever was significantly associated with Plasmodium infection (χ2= 12.44, p<0.001) and age (χ2=17.44, p=0.000). Conclusion: Results from this study indicate Plasmodium infection as the main cause of fever in the studied sites. While Plasmodium and Leptospira contribute to fevers, Rickettsia infection is an insignificant cause of fever in Northern Tanzania. Keywords: Neglected Infectious Diseases; Plasmodium; Leptospira; Rickettsia; co-occurrence; Tanzania.

scholarly journals Prevalence of Plasmodium falciparum Isolates Lacking the Histidine Rich Protein 2 Gene Among Symptomatic Malaria Patients in Kwilu Province, DR. Congo.

2020 ◽  
Author(s):  
Yannick Bazitama Munyeku ◽  
Alain Abera Musaka ◽  
Medard Ernest ◽  
Chris Smith ◽  
Paul Mankadi Mansiangi ◽  
...  
Keyword(s):  
Gene Deletion ◽  
Statistical Significance ◽  
False Negative ◽  
Secondary Data ◽  
Malaria Diagnosis ◽  
Malaria Prevention ◽  
Dr Congo ◽  
Cross Sectional ◽  
Gene Deletions ◽  
Symptomatic Malaria

Abstract BackgroundMalaria rapid diagnostic tests have become a primary and critical tool for malaria diagnosis in malaria-endemic countries where PfHRP2-based RDTs are widely used. However, in the last decade, the accuracy of PfHRP2-based RDTs has been challenged by the emergence of P. falciparum strains harbouring deletions of the pfhrp2 gene, resulting in false-negative results. In DR. Congo, little is known about the prevalence of the pfhrp2 gene deletion among P. falciparum isolates infecting symptomatic patients, especially in low to moderate transmission areas where pfhrp2 deletion parasites are assumed to emerge and spread. Here we determine the local prevalence and factors associated with pfhrp2 gene deletions among symptomatic malaria patients in the Kwilu province of the Democratic Republic of Congo, a low to moderate malaria transmission area.MethodsWe used secondary data from a prospective health facility-based cross-sectional study conducted on 684 individuals of all ages, seeking healthcare with symptoms suggestive of malaria from October to December 2018 in 34 randomly selected health facilities. Sociodemographic, malaria prevention and treatment practices, and clinical variables were collected using a pre-tested structured questionnaire. Patients’ medical records were used to collect additional clinical data. Blood was collected for microscopy, PfHRP2-RDT, and spotted onto Whatman filter paper for downstream genetic analysis. Genomic DNA was extracted and used to perform PCR assays for the detection and confirmation of pfhrp2 gene deletions. Data were entered and analysed using STATA15. Fischer’s exact and the Kruskal-Wallis tests were applied to look for associations between exposures and the pfhrp2 gene deletion with a level of statistical significance set at p < 0.05. ResultsThe overall prevalence of the pfhrp2 gene deletion was 9.2% (95% CI 6.7% – 12.1%). The deletion of the pfhrp2 gene was associated with health zone of origin (p=0.012) and age (p=0.019). Among false-negative PfHRP2-RDT results, only 9.9% were due to pfhrp2 gene deletion.ConclusionP. falciparum isolates with pfhrp2 gene deletions are relatively common among symptomatic patients in Kwilu province. Further investigations are needed to provide enough evidence for policy change. Meanwhile, the use of RDTs targeting PfHRP2 and pLDH antigens could limit the spread of deleted isolates.

scholarly journals Plasmodium falciparum Histidine-Rich Protein 2 and 3 Gene Deletions and Their Implications in Malaria Control

Diseases ◽  
2020 ◽  
Vol 8 (2) ◽  
pp. 15 ◽  
Author(s):  
Josphat Nyataya ◽  
John Waitumbi ◽  
Victor A. Mobegi ◽  
Ayman Noreddin ◽  
Mohamed E. El Zowalaty
Keyword(s):  
Plasmodium Falciparum ◽  
Case Management ◽  
Malaria Control ◽  
False Negative ◽  
Plasmodium Species ◽  
Malaria Diagnosis ◽  
Sub Saharan Africa ◽  
Metabolic Enzyme ◽  
Gene Deletions ◽  
Geographical Regions

Malaria remains the biggest threat to public health, especially among pregnant women and young children in sub-Saharan Africa. Prompt and accurate diagnosis is critical for effective case management and detection of drug resistance. Conventionally, microscopy and rapid diagnostic tests (RDTs) are the tools of choice for malaria diagnosis. RDTs are simple to use and have been extensively used in the diagnosis of malaria among travelers to malaria-endemic regions, routine case management, and surveillance studies. Most RDTs target the histidine-rich protein (PfHRP) which is exclusively found in Plasmodium falciparum and a metabolic enzyme Plasmodium lactate dehydrogenase (pLDH) which is common among all Plasmodium species. Other RDTs incorporate the enzyme aldolase that is produced by all Plasmodium species. Recently, studies have reported false-negative RDTs primarily due to the deletion of the histidine-rich protein (pfhrp2 and pfhrp3) genes in field isolates of P. falciparum. Herein, we review published literature to establish pfhrp2/pfhrp3 deletions, the extent of these deletions in different geographical regions, and the implication in malaria control. We searched for publications on pfhrp2/pfhrp3 deletions and retrieved all publications that reported on this subject. Overall, 20 publications reported on pfhrp2/pfhrp3 deletions, and most of these studies were done in Central and South America, with very few in Asia and Africa. The few studies in Africa that reported on the occurrence of pfhrp2/pfhrp3 deletions rarely evaluated deletions on the flanking genes. More studies are required to evaluate the existence and extent of these gene deletions, whose presence may lead to delayed or missed treatment. This information will guide appropriate diagnostic approaches in the respective areas.

scholarly journals Extensive Deletion and Sequence Variation of Plasmodium Falciparum Histidine Rich Protein 2/3 (pfhrp2/3) Genes in Ethiopia: Implication for RDT-based Malaria Diagnosis and Control

2020 ◽  
Author(s):  
Lemu Golassa ◽  
Alebachew Messele ◽  
Alfred Amambua-Ngwa ◽  
Gote Swedberg
Keyword(s):  
Plasmodium Falciparum ◽  
Sequence Variation ◽  
Public Health Problem ◽  
Malaria Diagnosis ◽  
Upstream Region ◽  
Cross Sectional ◽  
Gene Deletions ◽  
Upstream Gene ◽  
Blood Samples ◽  
Flanking Regions

Abstract Background: Despite remarkable malaria reduction in recent years, malaria remains a public health problem in Ethiopia. With the introduction of rapid diagnostic tests (RDTs), malaria diagnosis has been transformed. However, the Plasmodium falciparum histidine rich protein 2 ( hrp 2) that is targeted by the most widely used RDTs is prone to genetic mutations and gene deletions as observed in recent years. Patients infected with P. falciparum malaria parasites with a deletion in hrp 2/3 gene locus would remain undetected and results in ‘false-negatives’, which are not treated. Undoubtedly, these untreated infected patients are at risk of developing complicated disease and may further fuel parasite transmission. Hence, molecular targeting of the region across exons and flanking genes has been used to provide greater confirmatory evidence of gene deletions. This study was initiated to determine pfhrp2 /3 gene deletions including the flanking regions. Methods: A cross-sectional study was conducted to determine the prevalence of hrp 2/3 genes deletion.Finger-prick blood samples were collected from a total of 64 febrile patients attending Adama Malaria Diagnostic Centre in 2015. Thick and thin blood smears were prepared for microscopic slide readings, and parasitaemias were determined. Blood samples were spotted onto filter for parasite DNA extraction. Results: From a total of 64 microscopically and PCR confirmed P. falciparum infections, 50 were successfully analyzed for deletion of pfhrp2 , pfhrp3 and flanking regions. Extensive deletions were observed in the pfhrp2 gene with all 50(100%) isolates presenting a deletion. This deletion extended downstream towards the Pf3D7 0831900 (MAL7PI.230) gene in 11/50 (22%) cases. In contrast, only 2/50 (4%) of samples had deletions for the upstream gene Pf3D7 0831700 (MALPI.228). Similarly, all isolates had deleted the pfhrp3 gene (100%) and this in 40% of isolates extended to the downstream flanking region Pf3D7 13272400 (MAL13PI.485) where 40% samples showed absence of this region. However, the deletion also extended toward the upstream region Pf3D7 081372100 (MAL13PI.475). The deleted pfhrp 3 genomic region also extended upstream to the region Pf3D7 081372100 (MAL13PI.475) with 49/50 (95%) of the isolates exhibiting absence of the locus. Conclusion: As patient recruitment was not done on pfhrp 2/3-based RDTs, it is impossible to know if the isolates would test negative or positive in the absence of hrp 2/3 genes. Indeed, the sequence variation and high frequencies of deletion in pfhrp2 and pfhrp3 genes in Ethiopian isolates most likely will have a negative influence on the performance of currently used pfhrp2 RDTs. This study confirms the presence of that P. falciparum parasite population with extensive deletions of the pfhrp 2 and pfhrp3 genes in Ethiopia and this calls for a countrywide surveillance to determine the extent of these deletions and its effect on routine malaria diagnosis. Keywords: Plasmodium falciparum , Histidine rich protein 2/3, Deletion, RDTs, Microscopy, Ethiopia

scholarly journals High prevalence and extended deletions in Plasmodium falciparum hrp2/3 genomic loci in Ethiopia

PLoS ONE ◽  
2020 ◽  
Vol 15 (11) ◽  
pp. e0241807
Author(s):  
Lemu Golassa ◽  
Alebachew Messele ◽  
Alfred Amambua-Ngwa ◽  
Gote Swedberg
Keyword(s):  
Plasmodium Falciparum ◽  
Target Genes ◽  
False Negative ◽  
Malaria Diagnosis ◽  
Gene Deletions ◽  
Malaria Rapid Diagnostic Tests ◽  
High Prevalence ◽  
Filter Papers ◽  
Genomic Regions ◽  
Flanking Regions

Deletions in Plasmodium falciparum histidine rich protein 2(pfhrp2) gene threaten the usefulness of the most widely used HRP2-based malaria rapid diagnostic tests (mRDTs) that cross react with its structural homologue, PfHRP3. Parasites with deleted pfhrp2/3 genes remain undetected and untreated due to ‘false-negative’ RDT results. As Ethiopia recently launched malaria elimination by 2030 in certain selected areas, the availability of RDTs and the scale of their use have rapidly increased in recent years. Thus, it is important to explore the presence and prevalence of deletion in the target genes, pfhrp2 and pfhrp3. From a total of 189 febrile patients visited Adama Malaria Diagnostic centre, sixty-four microscopically-and polymerase chain reaction (PCR)-confirmed P. falciparum clinical isolates were used to determine the frequency of pfhrp2/3 gene deletions. Established PCR assays were applied to DNA extracted from blood spotted onto filter papers to amplify across pfhrp2/3 exons and flanking regions. However, analysis of deletions in pfhrp2, pfhrp3 and flanking genomic regions was successful for 50 of the samples. The pfhrp2 gene deletion was fixed in the population with all 50(100%) isolates presenting a deletion variant. This deletion extended downstream towards the Pf3D7 0831900 (MAL7PI.230) gene in 11/50 (22%) cases. In contrast, only 2/50 (4%) of samples had deletions for the Pf3D7 0831700 (MALPI.228) gene, upstream of pfhrp2. Similarly, the pfhrp3 gene was deleted in all isolates (100%), while 40% of the isolates had an extension of the deletion to the downstream flanking region that codes for Pf3D7 13272400 (MAL13PI.485).The pfhrp3 deletion also extended upstream to Pf3D7 081372100 (MAL13PI.475) region in 49/50 (95%) of the isolates, exhibiting complete absence of the locus. Although all samples showed deletions of pfhrp2 exon regions, amplification of an intron region was successful in five cases. Two different repeat motifs in the intron regions were observed in the samples tested. Pfhrp2/3 gene deletions are fixed in Ethiopia and this will likely reduce the effectiveness of PfHRP2-based mRDTs. It will be important to determine the sensitivity PfHRP 2/3-based RDTs in these populations and conduct a countrywide survey to determine the extent of these deletions and its effect on routine RDT-based malaria diagnosis.

Performance of PfHRP2 and PfPLDH Rapid Diagnostics Test for Diagnosis of Plasmodium falciparum in Assosa Zone, Northwest Ethiopia

2020 ◽  
Author(s):  
Gezahegn Solomon Alemayehu ◽  
Karen Lopez ◽  
Cheikh Dieng ◽  
Eugenia Lo ◽  
Daniel Janies ◽  
...  
Keyword(s):  
Plasmodium Falciparum ◽  
Predictive Value ◽  
False Negative ◽  
Reference Method ◽  
Malaria Diagnosis ◽  
Northwest Ethiopia ◽  
Blood Film ◽  
Limited Information ◽  
Rapid Diagnostics ◽  
Cross Sectional

Abstract Background Malaria is a life-threatening infectious disease particularly due to Plasmodium falciparum (P.falciparum ). Plasmodium falciparum Histidine-Rich Protein 2 (PfHRP-2) and Plasmodium falciparum specific Lactate Dehydrogenase (PfPLDH) based rapid diagnostic test are commonly used for malaria diagnosis in malaria endemic countries where microscopic examination is scarce. However, there is limited information on the performance of malaria RDT in rural and semi urban area of Assosa zone, Northwest Ethiopia. Thus, the aim of this study is to determine the performance of PfHRP2 and PfPLDH RDT for diagnosis of falciparum malaria against microscopy as reference method. Methods Health-facility based cross-sectional study design was conducted in Assosa zone, Northwest Ethiopia from November to December 2018. A total of four hundred and six malaria-suspected participants attending Bambasi, Sherkole, Kurmuk and Assosa health-centers were tested. Finger-prick blood samples were collected for microscopy blood film preparation, RDTs and molecular diagnosis. Statistical analyses were performed using SPSS version 20. Results Of the total study participants, 26.4% (107/406) were microscope confirmed P. falciparum positive. Using PfHRP2 and PfPLDH RDT, 30.3% (123/406) and 24.1% (98/406) were positive for P. falciparum, respectively. The sensitivity of PfHRP2 and PfPLDH was 96% and 89%, respectively, against microscope. The corresponding specificity rates of PfHRP2 and PfPLDH were 93% and 99%, respectively. Similarly, positive predictive value (PPV) and negative predictive value of PfHRP2 and PfPLDH RDT were 84%, 97%, 99% and 96%, respectively. There was an agreement between RDTs (PfPLDH and PfHRP2) and reference microscopy method with a kappa value of 0.86 and 0.90, respectively. Compared to qPCR, the specificity of PfHRP2 (93%) and PfPLDH RDT (98%) were high, though the respective sensitivity of PfHRP2(77%) and PfPLDH RDT(70%) were low. Conclusion PfHRP2 and PfPLDH showed reasonable agreement in detecting P. falciparum infections. Hence, currently used national malaria RDT kit can be continue to be used in certain malaria endemic areas in Ethiopia. However, Continuous monitoring the performance of PfHRP-2 RDT associated with false negative results is important to consider an alternative malaria RDT like PfPLDH RDT to support control and elimination of malaria in Ethiopia

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