scholarly journals Molecular detection and quantification of Plasmodium falciparum gametocytes carriage in used RDTs in malaria elimination settings in northern Senegal

2020 ◽  
Author(s):  
Kiswendsida Thierry Guiguemde ◽  
Yakou Dieye ◽  
Aminata Collé Lô ◽  
Magatte Ndiaye ◽  
Aminata Lam ◽  
...  
Keyword(s):  
Plasmodium Falciparum ◽  
Malaria Transmission ◽  
Malaria Elimination ◽  
Large Scale ◽  
Molecular Techniques ◽  
Molecular Monitoring ◽  
Malaria Surveillance ◽  
Saint Louis ◽  
Gametocyte Carriage ◽  
Chelex 100

Abstract Background: Malaria surveillance requires powerful tools and strategies to achieve malaria elimination. Rapid diagnostic tests for malaria (RDTs) are easily deployed on a large scale and are helpful sources for the parasite's DNA. The application of sensitive molecular techniques to these RDTs is a modern tool for improving malaria case detection and drug resistance surveillance. Several studies have made it possible to extract the DNA of P. falciparum on these RDTs. The knowledge of gametocyte carriage in the population is important to better assess the level of parasite transmission in elimination settings. The aim of this study was to detect P. falciparum gametocytes from used RDTs by quantitative PCR technique in order to use this new tool for molecular monitoring of malaria transmission. Methods: DNA was extracted from 303 RDT devices (SD Bioline Malaria Pf) using the Chelex-100 protocol. qPCR was performed in a 20 μL reaction to detect and quantify transcripts of the pfs25 gene. The cycle threshold (Ct) was determined by the emission fluorescence corresponding to the initial amount of amplified DNA. Results: We found an overall prevalence of 53.47% with an average Ct of 32.12 ± 4.28 cycles. In 2018, the prevalence of gametocytes was higher in the Ranérou district (76.24%) than in the Saint-Louis district (67.33%) where an increase in the number of gametocyte carriers in 2018 was noted, in comparison with 2017. Conclusions: RDTs are a good source of DNA for molecular monitoring of gametocyte carriage. This method, described for the first time, is a simple and effective tool to better understand the level of malaria transmission and reach elimination. Keywords: Malaria, RDT, Gametocytes, DNA extraction, Quantification, Plasmodium falciparum , qPCR.

scholarly journals Molecular detection and quantification of Plasmodium falciparum gametocytes carriage in used RDTs in malaria elimination settings in northern Senegal

2020 ◽  
Author(s):  
Kiswendsida Thierry Guiguemde ◽  
Yakou Dieye ◽  
Aminata Collé Lô ◽  
Magatte Ndiaye ◽  
Aminata Lam ◽  
...  
Keyword(s):  
Plasmodium Falciparum ◽  
Malaria Transmission ◽  
Malaria Elimination ◽  
Large Scale ◽  
Molecular Techniques ◽  
Molecular Monitoring ◽  
Malaria Surveillance ◽  
Saint Louis ◽  
Gametocyte Carriage ◽  
Chelex 100

Abstract Background: Malaria surveillance requires powerful tools and strategies to achieve malaria elimination. Rapid diagnostic tests for malaria (RDTs) are easily deployed on a large scale and are helpful sources for the parasite's DNA. The application of sensitive molecular techniques to these RDTs is a modern tool for improving malaria case detection and drug resistance surveillance. Several studies have made it possible to extract the DNA of P. falciparum on these RDTs. The knowledge of gametocyte carriage in the population is important to better assess the level of parasite transmission in elimination settings. The aim of this study was to detect P. falciparum gametocytes from used RDTs by quantitative PCR technique in order to use this new tool for molecular monitoring of malaria transmission. Methods: DNA was extracted from 303 RDT devices (SD Bioline Malaria Pf) using the Chelex-100 protocol. qPCR was performed in a 20 μL reaction to detect and quantify transcripts of the pfs25 gene. The cycle threshold (Ct) was determined by the emission fluorescence corresponding to the initial amount of amplified DNA. Results: We found an overall prevalence of 53.47% with an average Ct of 32.12 ± 4.28 cycles. In 2018, the prevalence of gametocytes was higher in the Ranérou district (76.24%) than in the Saint-Louis district (67.33%) where an increase in the number of gametocyte carriers in 2018 was noted, in comparison with 2017. Conclusions: RDTs are a good source of DNA for molecular monitoring of gametocyte carriage. This method, described for the first time, is a simple and effective tool to better understand the level of malaria transmission and reach elimination. Keywords: Malaria, RDT, Gametocytes, DNA extraction, Quantification, Plasmodium falciparum , qPCR.

scholarly journals Molecular detection and quantification of Plasmodium falciparum gametocytes carriage in used RDTs in malaria elimination settings in northern Senegal

2019 ◽  
Author(s):  
Kiswendsida Thierry Guiguemde ◽  
Yakou Dieye ◽  
Aminata Collé Lô ◽  
Magatte Ndiaye ◽  
Aminata Lam ◽  
...  
Keyword(s):  
Plasmodium Falciparum ◽  
Malaria Elimination ◽  
Large Scale ◽  
Molecular Techniques ◽  
Molecular Monitoring ◽  
Malaria Surveillance ◽  
Saint Louis ◽  
Gametocyte Carriage ◽  
Chelex 100 ◽  
First Time

Abstract Background: Malaria surveillance requires powerful tools and strategies to achieve malaria elimination. Rapid diagnostic tests for malaria (RDTs) are easily deployed on a large scale and are helpful sources for the parasite's DNA. The application of sensitive molecular techniques to these RDTs is a modern tool for improving malaria case detection and drug resistance surveillance. However, the detection of the parasite with these RDT based tools has so far only concerned asexual forms of P. falciparum. The knowledge of gametocyte carriage in the population is important to better assess the level of parasite transmission in elimination settings. The aim of this study was to develop the quantitative real time PCR technique to detect gametocytes of P. falciparum from RDTs and to provide a new tool for the molecular monitoring of malaria transmission.Methods: DNA was extracted from 303 RDT devices (SD Bioline Malaria Pf) using the Chelex-100 protocol. qPCR was performed in a 20 μL reaction to detect and quantify transcripts of the pfs25 gene. The cycle threshold (Ct) was determined by the emission fluorescence corresponding to the initial amount of amplified DNA. Results: We found an overall prevalence of 53.47% with an average Ct of 32.12 ± 4.28 cycles. In 2018, the prevalence of gametocytes was higher in the Ranérou district (76.24%) than in the Saint-Louis district (67.33%) where an increase in the number of gametocyte carriers in 2018 was noted, in comparison with 2017. Conclusions: RDTs are a good source of DNA for molecular monitoring of gametocyte carriage. This method, described for the first time, is a simple and effective tool to better understand the level of malaria transmission and reach elimination. Keywords: Malaria, RDT, Gametocytes, DNA extraction, Quantification, Plasmodium falciparum, qPCR.

scholarly journals Studi Bioekologi Vektor Malaria di Daerah (Yang Mendapat Sertifikat) Eliminasi Malaria di Kabupaten Jembrana, Bengkalis dan Bulukumba

2020 ◽  
Vol 47 (4) ◽  
Author(s):  
Riyani Setiyaningsih
Keyword(s):  
Plasmodium Falciparum ◽  
Malaria Transmission ◽  
Malaria Vector ◽  
Malaria Elimination ◽  
Forest Ecosystems ◽  
Malaria Vectors ◽  
Vector Surveillance ◽  
South Sulawesi ◽  
Anopheles Barbirostris ◽  
Anopheles Vagus

Abstract The target of malaria elimination in Indonesia is expected to be achieved in 2030. One of the activities to support malaria elimination is vector surveillance. Several districts in Indonesia have certificates of malaria, including Jembrana, Bali Province, Bulukumba, South Sulawesi Province, and Bengkalis, Riau Province. Analysis of the presence of malaria vectors and Plasmodium needs to be done for the potential occurances of malaria transmission in eliminated malaria areas. Bioecology study of malaria vectors were conducted to determine receptivity status and others risk factors and the potential for malaria transmission based on ecosystems in Jembrana, Bulukumba and Bengkalis districts. As part of national research of disease vector and reservoir (Rikhus Vektora), mosquitoes and larval field-collection methods, molecular plasmodium detection and blood meal analyses were carried out according Rikhus vektora guidelines. The result showed that Anopheles kochi and An. tesselatus were positive confirmed with Plasmodium falciparum by using PCR in Jembrana, Bali province, which were found in non-forest ecosystems near settlements and beaches near settlements. In addition, Anopheles barbirostris, Anopheles vagus, and Anopheles peditaeniatus were also positive confirmed with P. falciparum by using similar methods in Bulukumba, South Sulawesi province. An. barbirostris was found in forest ecosystems near settlement, Anopheles vagus was found in remote forest ecosystems of settlements and beaches near settlements, and Anopheles peditaenistus was found in non-forest ecosystems near settlements. While Anopheles sinensis was confirmed positive with P. falciparum in Bengkalis, Riau province. Jembrana, Bulukumba and Bengkalis districts are recognized as receptive areas and have potential for re-transmission of malaria. Vector surveillance and the implementation of approriate vector control and migration surveillance are needed to ascertain wheter the positive Anopheles with positives Plasmodium falciparum getting the parasites from imported cases or there has been a local transmission (indigenous) in these areas. This information is needed to prevent malaria re-transmission in the eliminated areas. Keywords : elimination, malaria, vector Abstrak Target eliminasi malaria di Indonesia harapannya dapat dicapai tahun 2030. Salah satu kegiatan yang dilakukan untuk menunjang elimnasi malaria adalah surveilans vektor. Beberapa Kabupaten di Indonesia telah memperoleh serfikat eliminasi malaria diantaranya Kabupaten Jembrana Propinsi Bali, Bulukumba Propinsi Sulawesi Selatan, dan Bengkalis Propinsi Riau. Analisis keberadaan vektor dan patogen malaria perlu dilakukan untuk melihat potensi terjadinya penularan malaria kembali di daerah yang telah mendapatkan sertifikat eliminasi malaria. Studi bioekologi vektor malaria dilakukan untuk mengetahui status reseptivitas dan faktor risiko lainnya, serta potensi penularan malaria berbasis ekosistem di daerah tersebut. Sebagai bagian dari dari Riset khusus (rikhus) vektora, koleksi lapangan nyamuk dan jentik, prosedur deteksi melekuler plasmodium dan analisis pakan darah dilakukan dengan menggunakan pedoman Rikhus vektora. Hasil studi menunjukkan bahwa Anopheles kochi dan Anopheles tesselatus, yang masing-masing ditemukan di eksoistem non hutan dekat pemukiman dan pantai dekat pemukiman ditemukan positif mengandung Plasmodium falciparum di Kabupaten Jembrana, Bali. Sedangkan di Kabupaten Bulukumba, Sulawesi Selatan, Anopheles barbirostris, Anopheles vagus, dan Anopheles peditaeniatus merupakan spesies Anopheles yang terkonfirmasi positif mengandung P. falciparum. An. barbirostris ditemukan di ekosistem hutan dekat pemukiman, Anopheles vagus ditemukan di ekosistem hutan jauh pemukiman dan pantai dekat pemukiman, dan Anopheles peditaenistus ditemukan di ekosistem non hutan dekat pemukiman. Sedangkan Anopheles sinensis merupakan satu-satunya spesies Anopheles yang ditemukan positif mengandung P. falciparum di Kabupaten Bengkalis, Riau. Dari hasil studi menunjukkan, Kabupaten Jembrana, Bulukumba, dan Bengkalis merupakan daerah reseptif dan berpotensi terjadinya penularan kembali malaria. Surveilans vektor dan implementasi pengendalian vektor yang tepat serta surveilans migrasi secara ketat diperlukan untuk memastikan apakah Anopheles yang positif tersebut mendapatkan parasit P. falciparum dari kasus import ataukah memang sudah terjadi transmisi secara lokal (indigenous) di wilayah tersebut. Hal ini perlu dilakukan agar tidak terjadi penularan kembali malaria di daerah yang sudah tereliminasi tersebut. Kata kunci: eliminasi, malaria, vektor

scholarly journals Modeling the levels, trends, and connectivity of malaria transmission using genomic data from a health facility in Thiès, Senegal

2021 ◽  
Author(s):  
Albert Lee ◽  
Yaye Die Ndiaye ◽  
Aida Badiane ◽  
Awa Deme ◽  
Rachel F Daniels ◽  
...  
Keyword(s):  
Malaria Transmission ◽  
Malaria Parasite ◽  
Large Scale ◽  
Time Series Data ◽  
Model Fitting ◽  
Genetic Data ◽  
Series Data ◽  
Multiple Infections ◽  
Malaria Surveillance ◽  
Neighborhood Scale

Molecular data and analysis outputs are being integrated into malaria surveillance efforts to provide valuable programmatic insights for national malaria control programs (NMCPs). A plethora of studies from diverse geographies have demonstrated that malaria parasite genetic data can be an important tool for drug resistance monitoring, species identification, outbreak analysis, and transmission characterization. Despite many successful research efforts, there are still important knowledge gaps hindering practical translation of each of these use cases for NMCPs. Here, we leverage epidemiological modeling and time series data of 2035 genetic sequences collected in Thi`es, Senegal from 2006-2018 to provide a quantitative and setting-specific assessment of the levels, trends, and connectivity of malaria transmission. We also identify the genetic features that are the most informative for inferring transmission in Thi`es, such as the fraction of the population with multiple infections and the persistence of parasite lineages across multiple transmission seasons. The model fitting and uncertainty quantification framework also reveals a significant decrease in the level of malaria transmission around 2013. This difference coincides with a large-scale drought and bed net campaign by the NMCP and USAID and is independently corroborated by geo-spatial models of incidence in Thi`es. We find that genetically identical samples are more likely to be geographically clustered even at the neighborhood scale; and moreover, these lineages propagate non-randomly around the city. Our approach and results provide quantitative guidance for the interpretation of malaria parasite genetic data from Thi`es, Senegal and indicates the value of increased malaria genomic surveillance for NMCPs.

scholarly journals Spotlight on Plasmodium falciparum evolutionary system in the southeastern Atlantic forest

2017 ◽  
Vol 17 (3) ◽  
Author(s):  
Gabriel Zorello Laporta
Keyword(s):  
Public Health ◽  
Plasmodium Falciparum ◽  
Malaria Transmission ◽  
Atlantic Forest ◽  
Malaria Elimination ◽  
Evolutionary Perspective ◽  
Evolutionary System ◽  
Residual Malaria Transmission ◽  
Southeastern Atlantic

Abstract Malaria elimination is now set to occur in Brazil until 2030. While this achievement is feasible, as it is for other endemic regions worldwide, it is important to recognize resistance of parasites and vectors against anti-malarial interventions. Resistance against drugs and insecticides can lead to discontinuities of malaria transmission, known as residual malaria transmission. Herein, we described a novel phenomenon that is occurring in a residual malaria transmission scenario in the southeastern Atlantic forest. This novel phenomenon does not belong to what is known and therefore we decided to explain it based on an evolutionary perspective. Although it shall not be viewed as a threat to public health, the phenomenon has important aspects that should be highlighted. Specifically, it represents an adaptation of P. falciparum among vectors and hosts in the southeastern Atlantic forest. Knowledge about this phenomenon could be of importance, including to the on-going malaria elimination programs.

scholarly journals Antibody Responses to Crude Gametocyte Extract Predict Plasmodium falciparum Gametocyte Carriage in Kenya

2021 ◽  
Vol 11 ◽  
Author(s):  
Brian R. Omondi ◽  
Michelle K. Muthui ◽  
William I. Muasya ◽  
Benedict Orindi ◽  
Ramadhan S. Mwakubambanya ◽  
...  
Keyword(s):  
Plasmodium Falciparum ◽  
Logistic Regression ◽  
Malaria Transmission ◽  
Predictive Power ◽  
Antibody Responses ◽  
Asexual Parasite ◽  
Igg Antibody ◽  
Gametocyte Carriage ◽  
Multivariable Logistic Regression ◽  
Multivariable Models

BackgroundMalaria caused by Plasmodium falciparum remains a serious global public health challenge especially in Africa. Interventions that aim to reduce malaria transmission by targeting the gametocyte reservoir are key to malaria elimination and/or eradication. However, factors that are associated with gametocyte carriage have not been fully explored. Consequently, identifying predictors of the infectious reservoir is fundamental in the elimination campaign.MethodsWe cultured P. falciparum NF54 gametocytes (to stage V) and prepared crude gametocyte extract. Samples from a total of 687 participants (aged 6 months to 67 years) representing two cross-sectional study cohorts in Kilifi, Kenya were used to assess IgG antibody responses by ELISA. We also analyzed IgG antibody responses to the blood-stage antigen AMA1 as a marker of asexual parasite exposure. Gametocytemia and asexual parasitemia data quantified by microscopy and molecular detection (QT-NASBA) were used to determine the relationship with antibody responses, season, age, and transmission setting. Multivariable logistic regression models were used to study the association between antibody responses and gametocyte carriage. The predictive power of the models was tested using the receiver operating characteristic (ROC) curve.ResultsMultivariable logistic regression analysis showed that IgG antibody response to crude gametocyte extract predicted both microscopic (OR=1.81 95% CI: 1.06–3.07, p=0.028) and molecular (OR=1.91, 95% CI: 1.11–3.29, p=0.019) P. falciparum gametocyte carriage. Antibody responses to AMA1 were also associated with both microscopic (OR=1.61 95% CI: 1.08–2.42, p=0.020) and molecular (OR=3.73 95% CI: 2.03–6.74, p<0.001) gametocytemia. ROC analysis showed that molecular (AUC=0.897, 95% CI: 0.868–0.926) and microscopic (AUC=0.812, 95% CI: 0.758–0.865) multivariable models adjusted for gametocyte extract showed very high predictive power. Molecular (AUC=0.917, 95% CI: 0.891–0.943) and microscopic (AUC=0.806, 95% CI: 0.755–0.858) multivariable models adjusted for AMA1 were equally highly predictive.ConclusionIn our study, it appears that IgG responses to crude gametocyte extract are not an independent predictor of gametocyte carriage after adjusting for AMA1 responses but may predict gametocyte carriage as a proxy marker of exposure to parasites. Serological responses to AMA1 or to gametocyte extract may facilitate identification of individuals within populations who contribute to malaria transmission and support implementation of transmission-blocking interventions.

scholarly journals Gametocyte clearance in children, from western Kenya, with uncomplicated Plasmodium falciparum malaria after artemether–lumefantrine or dihydroartemisinin–piperaquine treatment

2019 ◽  
Vol 18 (1) ◽  
Author(s):  
Protus Omondi ◽  
Marion Burugu ◽  
Damaris Matoke-Muhia ◽  
Edwin Too ◽  
Eva A. Nambati ◽  
...  
Keyword(s):  
Plasmodium Falciparum ◽  
Malaria Transmission ◽  
Plasmodium Falciparum Malaria ◽  
Western Kenya ◽  
Transmission Season ◽  
Gametocyte Carriage ◽  
Qrt Pcr ◽  
Malaria Transmission Season ◽  
Significant Difference ◽  
Blocking Malaria Transmission

Abstract Background The efficacy and safety of artemether–lumefantrine (AL) and dihydroartemisinin–piperaquine (DP) against asexual parasites population has been documented. However, the effect of these anti-malarials on sexual parasites is still less clear. Gametocyte clearance following treatment is essential for malaria control and elimination efforts; therefore, the study sought to determine trends in gametocyte clearance after AL or DP treatment in children from a malaria-endemic site in Kenya. Methods Children aged between 0.5 and 12 years from Busia, western Kenya with uncomplicated Plasmodium falciparum malaria were assigned randomly to AL or DP treatment. A total of 334 children were enrolled, and dried blood spot samples were collected for up to 6 weeks after treatment during the peak malaria transmission season in 2016 and preserved. Plasmodium falciparum gametocytes were detected by qRT-PCR and gametocyte prevalence, density and mean duration of gametocyte carriage were determined. Results At baseline, all the 334 children had positive asexual parasites by microscopy, 12% (40/334) had detectable gametocyte by microscopy, and 83.7% (253/302) children had gametocytes by RT-qPCR. Gametocyte prevalence by RT-qPCR decreased from 85.1% (126/148) at day 0 to 7.04% (5/71) at day 42 in AL group and from 82.4% (127/154) at day 0 to 14.5% (11/74) at day 42 in DP group. The average duration of gametocyte carriage as estimated by qRT-PCR was slightly shorter in the AL group (4.5 days) than in the DP group (5.1 days) but not significantly different (p = 0.301). Conclusion The study identifies no significant difference between AL and DP in gametocyte clearance. Gametocytes persisted up to 42 days post treatment in minority of individuals in both treatment arms. A gametocytocidal drug, in combination with artemisinin-based combination therapy, will be useful in blocking malaria transmission more efficiently.

scholarly journals Ultrasensitive diagnostics for low density asymptomatic Plasmodium falciparum infections in low transmission settings

2020 ◽  
Author(s):  
Kayvan Zainabadi
Keyword(s):  
Plasmodium Falciparum ◽  
Malaria Elimination ◽  
Field Performance ◽  
Dried Blood Spots ◽  
Multidrug Resistant ◽  
Current Status ◽  
Malaria Surveillance ◽  
Low Transmission ◽  
Large Populations ◽  
Asymptomatic Individuals

The emergence of multidrug resistant Plasmodium falciparum malaria in Southeast Asia has accelerated regional malaria elimination efforts. Most malaria in this and other low transmission settings exists in asymptomatic individuals, which conventional diagnostic tests lack the sensitivity to detect. This has led to the development of new ultrasensitive diagnostics that are capable of detecting these low parasitemic infections. This review summarizes the current status of ultrasensitive technologies, including PCR and LAMP-based methods, as well as a newly developed ultrasensitive rapid diagnostic test (uRDT). The sensitivity, specificity, and field performance of these platforms will be examined, as well as their suitability for use in resource limited settings to aid in malaria elimination efforts. uRDTs, with their improved sensitivity, are now able to detect approximately half of asymptomatic infections, providing a useful point of contact tool for malaria surveillance. The increased sensitivity and high-throughput nature of PCR-based tests make them ideal for screening large populations in places where laboratory capacity exists, and the recent commercialization of malaria LAMP kits should facilitate their adoption as a public health tool in places where such infrastructure is lacking. Finally, recent advances with dried blood spots may enable the utilization of the extensive laboratory infrastructure of higher income countries to assist with molecular surveillance in support of malaria elimination. If malaria is to be eliminated in SEA and other low endemic regions, then ultrasensitive diagnostics may play a key role in identifying and clearing the vast asymptomatic pool of infections that are common to these regions.

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