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Paul KMM, Simpson SV, Nundu SS, Arima H, Yamamoto T. Genetic diversity of glutamate-rich protein (GLURP) in Plasmodium falciparum isolates from school-age children in Kinshasa, DRC. Parasitol Int 2024; 100:102866. [PMID: 38350548 DOI: 10.1016/j.parint.2024.102866] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2023] [Revised: 02/08/2024] [Accepted: 02/09/2024] [Indexed: 02/15/2024]
Abstract
Malaria infections in school-age children further make it difficult to control the disease's spread. Moreover, the genetic diversity of glutamate-rich protein, potentially a candidate for vaccine development, has not yet been investigated in the Democratic Republic of Congo. Therefore, we aimed to assess the genetic diversity of the immunodominant C-terminal repetitive region (R2) of Plasmodium falciparum glutamate-rich protein gene (pfglurp) among school-age children living in Kinshasa, DRC. We conducted nested PCR targeting R2 of pfglurp and the amplicon were directly sequenced. We summarized the prevalence of mutations of bases and amino acids and indicated the amino acid repeat sequence in the R2 region by the unit code. We then statistically analyzed whether there was a relationship between the number of mutations in the pfglurp gene and attributes. In 221 samples, haplotype 1 was the most common (n = 137, 61.99%), with the same sequence as the 3D7 strain. Regarding the number of base mutations, it was higher in urban areas than rural areas (p = 0.0363). When genetic neutrality was tested using data from 171 samples of the single strain, Tajima's D was -1.857 (p = 0.0059). In addition, FST as the genetic distance between all attributes was very small and no significant difference was observed. This study clarified the genetic mutation status and relevant patient attributes among School-age children in the DRC. We found that urban areas are more likely to harbour pfglurp mutations. Future research needs to clarify the reason and mechanism involved.
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Affiliation(s)
- Kambale Mathe Mowa Paul
- Department of International Health and Medical Anthropology, Institute of Tropical Medicine, Nagasaki University, Nagasaki, Japan; Program for Nurturing Global Leaders in Tropical and Emerging Communicable Diseases, Nagasaki University, Nagasaki, Japan
| | - Shirley V Simpson
- Department of International Health and Medical Anthropology, Institute of Tropical Medicine, Nagasaki University, Nagasaki, Japan; Program for Nurturing Global Leaders in Tropical and Emerging Communicable Diseases, Nagasaki University, Nagasaki, Japan
| | - Sabin S Nundu
- Institut National de Recherche Biomédicale, Kinshasa, Democratic Republic of Congo
| | - Hiroaki Arima
- Department of International Health and Medical Anthropology, Institute of Tropical Medicine, Nagasaki University, Nagasaki, Japan.
| | - Taro Yamamoto
- Department of International Health and Medical Anthropology, Institute of Tropical Medicine, Nagasaki University, Nagasaki, Japan; Program for Nurturing Global Leaders in Tropical and Emerging Communicable Diseases, Nagasaki University, Nagasaki, Japan
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Ewnetu Y, Badu K, Carlier L, Vera-Arias CA, Troth EV, Mutala AH, Afriyie SO, Addison TK, Berhane N, Lemma W, Koepfli C. A digital microscope for the diagnosis of Plasmodium falciparum and Plasmodium vivax, including P. falciparum with hrp2/hrp3 deletion. PLOS GLOBAL PUBLIC HEALTH 2024; 4:e0003091. [PMID: 38768243 PMCID: PMC11104649 DOI: 10.1371/journal.pgph.0003091] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/13/2023] [Accepted: 03/18/2024] [Indexed: 05/22/2024]
Abstract
Sensitive and accurate malaria diagnosis is required for case management to accelerate control efforts. Diagnosis is particularly challenging where multiple Plasmodium species are endemic, and where P. falciparum hrp2/3 deletions are frequent. The Noul miLab is a fully automated portable digital microscope that prepares a blood film from a droplet of blood, followed by staining and detection of parasites by an algorithm. Infected red blood cells are displayed on the screen of the instrument. Time-to-result is approximately 20 minutes, with less than two minutes hands-on time. We evaluated the miLab among 659 suspected malaria patients in Gondar, Ethiopia, where P. falciparum and P. vivax are endemic, and the frequency of hrp2/3 deletions is high, and 991 patients in Ghana, where P. falciparum transmission is intense. Across both countries combined, the sensitivity of the miLab for P. falciparum was 94.3% at densities >200 parasites/μL by qPCR, and 83% at densities >20 parasites/μL. The miLab was more sensitive than local microscopy, and comparable to RDT. In Ethiopia, the miLab diagnosed 51/52 (98.1%) of P. falciparum infections with hrp2 deletion at densities >20 parasites/μL. Specificity of the miLab was 94.0%. For P. vivax diagnosis in Ethiopia, the sensitivity of the miLab was 97.0% at densities >200 parasites/μL (RDT: 76.8%, microscopy: 67.0%), 93.9% at densities >20 parasites/μL, and specificity was 97.6%. In Ethiopia, where P. falciparum and P. vivax were frequent, the miLab assigned the wrong species to 15/195 mono-infections at densities >20 parasites/μL by qPCR, and identified only 5/18 mixed-species infections correctly. In conclusion, the miLab was more sensitive than microscopy and thus is a valuable addition to the toolkit for malaria diagnosis, particularly for areas with high frequencies of hrp2/3 deletions.
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Affiliation(s)
- Yalemwork Ewnetu
- Department of Medical Biotechnology, Institute of Biotechnology, University of Gondar, Gondar, Ethiopia
- University of Gondar Comprehensive Specialized Hospital, Gondar, Ethiopia
| | - Kingsley Badu
- Department of Theoretical and Applied Biology, Kwame Nkrumah University of Science and Technology, Kumasi, Ghana
| | | | - Claudia A. Vera-Arias
- Department of Biological Sciences & Eck Institute for Global Health, University of Notre Dame, Notre Dame, Indiana, United States of America
| | - Emma V Troth
- Department of Biological Sciences & Eck Institute for Global Health, University of Notre Dame, Notre Dame, Indiana, United States of America
| | - Abdul-Hakim Mutala
- Department of Theoretical and Applied Biology, Kwame Nkrumah University of Science and Technology, Kumasi, Ghana
| | - Stephen Opoku Afriyie
- Department of Theoretical and Applied Biology, Kwame Nkrumah University of Science and Technology, Kumasi, Ghana
| | - Thomas Kwame Addison
- Department of Theoretical and Applied Biology, Kwame Nkrumah University of Science and Technology, Kumasi, Ghana
| | - Nega Berhane
- Department of Medical Biotechnology, Institute of Biotechnology, University of Gondar, Gondar, Ethiopia
| | - Wossenseged Lemma
- Department of Medical Parasitology, School of Biomedical and Laboratory Sciences, Collage of Medicine and Health Sciences, University of Gondar, Gondar, Ethiopia
| | - Cristian Koepfli
- Department of Biological Sciences & Eck Institute for Global Health, University of Notre Dame, Notre Dame, Indiana, United States of America
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Srisutham S, Rattanakoch P, Kijprasong K, Sugaram R, Kantaratanakul N, Srinulgray T, Dondorp AM, Imwong M. A novel sensitive hexaplex high-resolution melt assay for identification of five human Plasmodium species plus internal control. Acta Trop 2023; 248:107020. [PMID: 37739253 PMCID: PMC10641754 DOI: 10.1016/j.actatropica.2023.107020] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2023] [Revised: 09/05/2023] [Accepted: 09/11/2023] [Indexed: 09/24/2023]
Abstract
BACKGROUND The diagnosis of malaria infection in humans remains challenging, further complicated by mixed Plasmodium species infections, potentially altering disease severity and morbidity. To facilitate appropriate control measures and treatment, rapid, sensitive, and specific detection assays, including those for the second minor species, would be required. This study aimed to develop a multiplex high-resolution melting (hexaplex PCR-HRM) assay with seven distinct peaks corresponding to five Plasmodium species of the Plasmodium genus, and an internal control to limit false negatives providing quality assurance testing results. METHODS Five species-specific primers for human malaria species were designed targeting on the Plasmodium 18 small subunit ribosomal RNA (18S rRNA) and mitochondrial genes. The hexaplex PCR-HRM was developed for the simultaneous and rapid detection and differentiation of five human Plasmodium spp. The limit of detection (LoD), sensitivity, and specificity of the assay were evaluated. Artificial mixing was used to assess the ability to determine the second minor species. Furthermore, a hexaplex PCR-HRM assay was used to identify 120 Plasmodium-infected clinical isolates from Kanchanaburi, Western Thailand, where malaria is endemic. RESULTS The hexaplex PCR-HRM assay detected the targeted genome of five Plasmodium species at levels as low as 2.354-3.316 copies/uL with 91.76 % sensitivity and 98.04 % specificity. In artificial mixing, the assay could detect minority parasite species at 0.001 % of the predominant parasite population. Plasmodium vivax infections (99 %) accounted for the majority of malaria cases in Kanchanaburi, Thailand. CONCLUSIONS The developed hexaplex PCR-HRM assay we present in this study is a novel approach for multiplexing the Plasmodium genus and detecting five Plasmodium species with the advantage of detecting second minority parasite species. The developed one-step assay without any nesting protocols would reduce the risks of cross-contamination. Moreover, it also provides a simple, sensitive, specific, and low-cost approach for optional molecular detection of malaria.
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Affiliation(s)
- Suttipat Srisutham
- Department of Clinical Microscopy, Faculty of Allied Health Sciences, Chulalongkorn University, Bangkok, Thailand.
| | - Paweesuda Rattanakoch
- Department of Clinical Microscopy, Faculty of Allied Health Sciences, Chulalongkorn University, Bangkok, Thailand
| | | | - Rungniran Sugaram
- Division of Vector Borne Diseases, Department of Disease Control, Ministry of Public Health, Nonthaburi, Thailand
| | | | | | - Arjen M Dondorp
- Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand; Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, Northern Ireland UK
| | - Mallika Imwong
- Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand; Department of Molecular Tropical Medicine and Genetics, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand.
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Pugliese N, Samarelli R, Lombardi R, Schiavone A, Crescenzo G, Circella E, Zizzadoro C, Lai O, Saleh MS, Prioletti M, Camarda A. A Safe and Effective Atovaquone-Proguanil Therapeutic Protocol for the Treatment of Avian Malaria by Plasmodium relictum in Snowy Owl ( Bubo scandiacus). Animals (Basel) 2023; 13:3457. [PMID: 38003076 PMCID: PMC10668658 DOI: 10.3390/ani13223457] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2023] [Revised: 11/06/2023] [Accepted: 11/06/2023] [Indexed: 11/26/2023] Open
Abstract
Avian malaria is a re-emerging threat to avian species worldwide. It is sustained by several protozoan species belonging to the genus Plasmodium, mainly Plasmodium relictum. The even wider diffusion of the disease, probably because of the increase in the areas covered by their mosquito vectors, may pose new risks for avian species lacking natural resistance (especially those from artic or sub-artic environments) or those hosted in structures like zoos and wildlife rescue centers. With that premise, this study describes the efficacy and safety of a therapeutic protocol to treat avian malaria in three snowy owls (Bubo scandiacus) hosted in a wildlife rescue center in Apulia, south of Italy, and affected by avian malaria by P. relictum. The protocol consisted of administering 10/4 mg/kg atovaquone/proguanil per os once a day for three consecutive days, repeating this seven days later. Seven days after the end of the treatment, P. relictum was not detected in the birds' blood and no adverse effects were observed during the 60 days of monitoring after the end of the treatment. Therefore, a therapeutic regimen of 10/4 mg/kg/day may be considered safe and effective in a valuable and endangered species such as B. scandiacus.
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Nabet C, Brossas JY, Poignon C, Bouzidi A, Paris L, Touafek F, Varlet-Marie E, Sterkers Y, Passebosc-Faure K, Dardé ML, Piarroux R, Denis JA. Assessment of Droplet Digital PCR for the Detection and Absolute Quantification of Toxoplasma gondii: A Comparative Retrospective Study. J Mol Diagn 2023; 25:467-476. [PMID: 37068735 DOI: 10.1016/j.jmoldx.2023.03.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2022] [Revised: 01/16/2023] [Accepted: 03/30/2023] [Indexed: 04/19/2023] Open
Abstract
Accurate tools for Toxoplasma gondii detection and quantification can be valuable for the early and effective management of toxoplasmosis. Droplet digital PCR (ddPCR) is a next-generation end-point PCR technique with high performance. The objective of the study was to evaluate the performance of ddPCR for the detection and absolute quantification of T. gondii. From January 2019 to October 2020, DNA samples collected at the Laboratory of Parasitology and Mycology of Pitié-Salpêtrière Hospital in Paris were retrospectively analyzed by ddPCR and real-time quantitative PCR (qPCR). To detect T. gondii with the best sensitivity possible, the REP-529 multicopy target was used. For absolute quantification of T. gondii, a specific single-copy target of α-tubulin was designed. T. gondii detection by ddPCR and qPCR was strongly correlated (R2 = 0.93), with a total concordance of 96.7% (n = 145/150). Quantification of T. gondii using ddPCR was successful for 15 of 35 samples showing a parasite load ≥170 copies/mL of DNA eluate using the α-tubulin target. The qPCR REP-529 quantification based on a standard curve was approximate and dependent on the strain genotype, which led to an estimate of parasite copy number 14- to 160-fold superior to the ddPCR result. In total, ddPCR is an effective molecular method for T. gondii detection that shows equivalent performance to qPCR. For robust T. gondii quantification, ddPCR is clearly more accurate than semiquantitative qPCR methods.
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Affiliation(s)
- Cécile Nabet
- Sorbonne University, INSERM, Pierre-Louis Institute of Epidemiology and Public Health (IPLESP), Assistance Publique-Hôpitaux de Paris (AP-HP), Pitié-Salpêtrière Hospital, Parasitology and Mycology Department, Paris, France.
| | - Jean-Yves Brossas
- Sorbonne University, Parasitology and Mycology Department, AP-HP, Pitié-Salpêtrière Hospital, Paris, France
| | - Corentin Poignon
- Sorbonne University, Parasitology and Mycology Department, AP-HP, Pitié-Salpêtrière Hospital, Paris, France
| | - Amira Bouzidi
- Sorbonne University, INSERM, Research Unit on Cardiovascular and Metabolic Disease, Institut of Cardiometabolism and Nutrition (ICAN), Department of Endocrine Biochemistry and Oncology, AP-HP, Pitié-Salpêtrière Hospital, Paris, France
| | - Luc Paris
- Sorbonne University, Parasitology and Mycology Department, AP-HP, Pitié-Salpêtrière Hospital, Paris, France
| | - Feriel Touafek
- Sorbonne University, Parasitology and Mycology Department, AP-HP, Pitié-Salpêtrière Hospital, Paris, France
| | - Emmanuelle Varlet-Marie
- University of Montpellier, Centre National de la Recherche Scientifique (CNRS), Institut de Rechercher pour le Développement (IRD), MiVEGEC, University Hospital of Montpellier, Molecular Biology Pole of the National Reference Centre (CNR) for Toxoplasmosis, Montpellier, France
| | - Yvon Sterkers
- University of Montpellier, Centre National de la Recherche Scientifique (CNRS), Institut de Rechercher pour le Développement (IRD), MiVEGEC, University Hospital of Montpellier, Molecular Biology Pole of the National Reference Centre (CNR) for Toxoplasmosis, Montpellier, France
| | - Karine Passebosc-Faure
- National Reference Centre (CNR) for Toxoplasmosis/Toxoplasma Biological Research Centre (BRC), Dupuytren University Hospital Centre, Limoges, France
| | - Marie-Laure Dardé
- National Reference Centre (CNR) for Toxoplasmosis/Toxoplasma Biological Research Centre (BRC), Dupuytren University Hospital Centre, Limoges, France; Limoges University, INSERM, University Hospital Centre Limoges, Institut de Recherche pour le Développement (IRD), Tropical Neuroepidemiology Unit, Institute of Epidemiology and Tropical Neurology, Limoges, France
| | - Renaud Piarroux
- Sorbonne University, INSERM, Pierre-Louis Institute of Epidemiology and Public Health (IPLESP), Assistance Publique-Hôpitaux de Paris (AP-HP), Pitié-Salpêtrière Hospital, Parasitology and Mycology Department, Paris, France
| | - Jérôme Alexandre Denis
- Sorbonne University, INSERM, Saint-Antoine Research Centre, Cancer Biology and Therapeutics, Department of Endocrine Biochemistry and Oncology, AP-HP, Pitié-Salpêtrière Hospital, Paris, France
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van Bergen KJM, Stuitje AR, Akkers RC, Vermeer HJ, Castel R, Mank TG. Performance of a novel melting curve-based qPCR assay for malaria parasites in routine clinical practice in non-endemic setting. Malar J 2023; 22:191. [PMID: 37349789 DOI: 10.1186/s12936-023-04617-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2023] [Accepted: 06/06/2023] [Indexed: 06/24/2023] Open
Abstract
BACKGROUND High-quality malaria diagnosis is essential for effective treatment and clinical disease management. Microscopy and rapid diagnostic tests are the conventional methods performed as first-line malaria diagnostics in non-endemic countries. However, these methods lack the characteristic to detect very low parasitaemia, and accurate identification of the Plasmodium species can be difficult. This study evaluated the performance of the MC004 melting curve-based qPCR for the diagnosis of malaria in routine clinical practice in non-endemic setting. METHODS AND RESULTS Whole blood samples were collected from 304 patients with clinical suspicion of malaria and analysed by both the MC004 assay and conventional diagnostics. Two discrepancies were found between the MC004 assay and microscopy. Repeated microscopic analysis confirmed the qPCR results. Comparison of the parasitaemia of nineteen Plasmodium falciparum samples determined by both microscopy and qPCR showed the potential of the MC004 assay to estimate the parasite load of P. falciparum. Eight Plasmodium infected patients were followed after anti-malarial treatment by the MC004 assay and microscopy. The MC004 assay still detected Plasmodium DNA although no parasites were seen with microscopy in post-treatment samples. The rapid decline in Plasmodium DNA showed the potential for therapy-monitoring. CONCLUSION Implementation of the MC004 assay in non-endemic clinical setting improved the diagnosis of malaria. The MC004 assay demonstrated superior Plasmodium species identification, the ability to indicate the Plasmodium parasite load, and can potentially detect submicroscopic Plasmodium infections.
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Affiliation(s)
- Kim J M van Bergen
- Result Laboratorium, Albert Schweitzer Hospital, Albert Schweitzerplaats 25, 3300 AK, Dordrecht, The Netherlands.
| | - Antoine R Stuitje
- MRC Holland, Willem Schoutenstraat 1, 1057 DL, Amsterdam, The Netherlands
| | - Robert C Akkers
- Result Laboratorium, Albert Schweitzer Hospital, Albert Schweitzerplaats 25, 3300 AK, Dordrecht, The Netherlands
| | - Henricus J Vermeer
- Result Laboratorium, Albert Schweitzer Hospital, Albert Schweitzerplaats 25, 3300 AK, Dordrecht, The Netherlands
| | - Rob Castel
- Result Laboratorium, Albert Schweitzer Hospital, Albert Schweitzerplaats 25, 3300 AK, Dordrecht, The Netherlands
| | - Theo G Mank
- Regional Laboratory for Medical Microbiology and Public Health, Boerhaavelaan 26, 2035 RC, Haarlem, The Netherlands
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Chen S, Yin X, Han J, Sun W, Yao H, Song J, Li X. DNA barcoding in herbal medicine: Retrospective and prospective. J Pharm Anal 2023; 13:431-441. [PMID: 37305789 PMCID: PMC10257146 DOI: 10.1016/j.jpha.2023.03.008] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2022] [Revised: 03/07/2023] [Accepted: 03/25/2023] [Indexed: 06/13/2023] Open
Abstract
DNA barcoding has been widely used for herb identification in recent decades, enabling safety and innovation in the field of herbal medicine. In this article, we summarize recent progress in DNA barcoding for herbal medicine to provide ideas for the further development and application of this technology. Most importantly, the standard DNA barcode has been extended in two ways. First, while conventional DNA barcodes have been widely promoted for their versatility in the identification of fresh or well-preserved samples, super-barcodes based on plastid genomes have rapidly developed and have shown advantages in species identification at low taxonomic levels. Second, mini-barcodes are attractive because they perform better in cases of degraded DNA from herbal materials. In addition, some molecular techniques, such as high-throughput sequencing and isothermal amplification, are combined with DNA barcodes for species identification, which has expanded the applications of herb identification based on DNA barcoding and brought about the post-DNA-barcoding era. Furthermore, standard and high-species coverage DNA barcode reference libraries have been constructed to provide reference sequences for species identification, which increases the accuracy and credibility of species discrimination based on DNA barcodes. In summary, DNA barcoding should play a key role in the quality control of traditional herbal medicine and in the international herb trade.
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Affiliation(s)
- Shilin Chen
- Institute of Herbgenomics, Chengdu University of Traditional Chinese Medicine, Chengdu, 611137, China
- Key Laboratory of Beijing for Identification and Safety Evaluation of Chinese Medicine, Institute of Chinese Materia Medica, China Academy of Chinese Medical Sciences, Beijing, 100700, China
| | - Xianmei Yin
- Institute of Herbgenomics, Chengdu University of Traditional Chinese Medicine, Chengdu, 611137, China
- State Key Laboratory of Southwestern Chinese Medicine Resources, Chengdu University of Traditional Chinese Medicine, Chengdu, 611137, China
| | - Jianping Han
- Institute of Medicinal Plant Development, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, 100193, China
| | - Wei Sun
- Key Laboratory of Beijing for Identification and Safety Evaluation of Chinese Medicine, Institute of Chinese Materia Medica, China Academy of Chinese Medical Sciences, Beijing, 100700, China
| | - Hui Yao
- Institute of Medicinal Plant Development, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, 100193, China
| | - Jingyuan Song
- Institute of Medicinal Plant Development, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, 100193, China
| | - Xiwen Li
- Key Laboratory of Beijing for Identification and Safety Evaluation of Chinese Medicine, Institute of Chinese Materia Medica, China Academy of Chinese Medical Sciences, Beijing, 100700, China
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Murthy S, Suresh A, Dandasena D, Singh S, Subudhi M, Bhandari V, Bhanot V, Arora JS, Sharma P. Multiplex ddPCR: A Promising Diagnostic Assay for Early Detection and Drug Monitoring in Bovine Theileriosis. Pathogens 2023; 12:pathogens12020296. [PMID: 36839568 PMCID: PMC9965958 DOI: 10.3390/pathogens12020296] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2022] [Revised: 12/26/2022] [Accepted: 12/29/2022] [Indexed: 02/16/2023] Open
Abstract
Accurate quantification based on nucleic acid amplification is necessary to avoid the spread of pathogens, making early diagnosis essential. Droplet digital PCR (ddPCR) stands out for absolute parasite quantification because it combines microfluidics with the TaqMan test. This helps deliver maximum accuracy without needing a reference curve. This study assessed the efficacy of ddPCR as a detection tool for the bovine theileriosis (BT) caused by Theileria parasites. We developed and validated a duplex ddPCR method that detects and quantifies the Theileria genus (18S rRNA) and identifies clinically significant Theileria annulata parasites (TaSP) in experimental and clinical samples. ddPCR was shown to be as effective as qPCR throughout a 10-fold sample dilution range. However, ddPCR was more sensitive than qPCR at lower parasite DNA concentrations and reliably assessed up to 8.5 copies/µL of the TaSP gene in the infected DNA (0.01 ng) samples. The ddPCR was very accurate and reproducible, and it could follow therapeutic success in clinical cases of theileriosis. In conclusion, our ddPCR assays were highly sensitive and precise, providing a valuable resource for the study of absolute parasite quantification, drug treatment monitoring, epidemiological research, large-scale screening, and the identification of asymptomatic parasite reservoirs in the pursuit of BT eradication.
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Affiliation(s)
- Shweta Murthy
- National Institute of Animal Biotechnology, Hyderabad 500032, India
| | - Akash Suresh
- National Institute of Animal Biotechnology, Hyderabad 500032, India
| | - Debabrata Dandasena
- National Institute of Animal Biotechnology, Hyderabad 500032, India
- Graduate Studies, Regional Centre for Biotechnology (RCB), Faridabad 121001, India
| | - Sakshi Singh
- National Institute of Animal Biotechnology, Hyderabad 500032, India
- Graduate Studies, Regional Centre for Biotechnology (RCB), Faridabad 121001, India
| | - Madhusmita Subudhi
- National Institute of Animal Biotechnology, Hyderabad 500032, India
- Graduate Studies, Regional Centre for Biotechnology (RCB), Faridabad 121001, India
| | - Vasundhra Bhandari
- National Institute of Animal Biotechnology, Hyderabad 500032, India
- Graduate Studies, Regional Centre for Biotechnology (RCB), Faridabad 121001, India
- National Institute of Pharmaceutical Education and Research (NIPER), Hyderabad 500037, India
| | - Vandna Bhanot
- Disease Investigation Laboratory, LUVAS (Hisar), Haryana 125011, India
| | | | - Paresh Sharma
- National Institute of Animal Biotechnology, Hyderabad 500032, India
- Correspondence:
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Dong L, Li W, Xu Q, Gu J, Kang Z, Chen J, Xu X, Zhang X, Zhang X, Jiang H, Guan M. A rapid multiplex assay of human malaria parasites by digital PCR. Clin Chim Acta 2023; 539:70-78. [PMID: 36495929 DOI: 10.1016/j.cca.2022.12.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2022] [Revised: 11/25/2022] [Accepted: 12/01/2022] [Indexed: 12/12/2022]
Abstract
BACKGROUND Blood smear examination through traditional optical microscopy is the gold standard for malaria diagnosis. However, it imposes strict requirements for operational staff and its sensitivity cannot perfectly satisfy the needs of clinical requirements. More sensitive and accurate modern technologies should be applied to this field. Digital PCR (dPCR), as an absolute quantification detection method, can serve as an effective tool to facilitate the diagnosis and classification of different malaria species. OBJECTIVE We aimed to establish a new multiplex dPCR detection system for four main Plasmodium species: P. vivax, P. falciparum, P. ovale and P. malariae, which can distinguish exact species of malaria by one PCR reaction. METHODS A total of 39 patients were identified as malaria-positive by microscopic examination in Huashan Hospital from 2016 to 2021; seventy blood samples from these patients were collected. Additionally, 20 healthy individuals, 20 patients with fever and 6 patients with other types of blood parasites infection were also included in this study. Each blood sample was subjected to examination by both blood smears and dPCR. By optimizing four different fluorescence-labeled probes in one reaction system, dPCR permitted the performance of accurate quantitation and working out the exact number of copies of malaria DNA per microliter in whole blood. Rapid diagnostic tests were also conducted to verify part of the results obtained by dPCR. RESULTS The dPCR system was able to make rapid diagnosis and quantification of malaria DNA samples. The analytical sensitivity of multiplex dPCR was as low as 0.557 copies/μL (95% CI 0.521 to 0.607), and it had a sensitivity of 98.0% and a specificity of 100% in clinical samples. Additionally, three multiple malaria co-infection samples have been detected by this dPCR system, including one triple malaria infection case. By testing consecutive daily blood samples of Patient 39, dPCR facilitated monitoring the efficacy of drug treatment. It showed that the DNA concentrations of P. falciparum ranged from 5474 copies/μL to 0 copies/μL, which can reflect the efficacy of antimalarials in real time. This study also found that haemocyte samples (plasma removed) rather than whole blood had higher malaria detection capability and an enhanced positive rate. CONCLUSION The multiplex dPCR system newly established here made a substantial contribution in detecting malaria infection at low concentrations. It is suitable for mixed-infection diagnosis and multi-sample continuous monitoring, and presents a promising candidate as an absolute quantitative tool in clinical practice.
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Affiliation(s)
- Liu Dong
- Department of Laboratory Medicine, Huashan Hospital, Fudan University, Shanghai, 200040, PR China
| | - Weijia Li
- Department of Equipment, Huashan Hospital, Fudan University, Shanghai, PR China
| | - Qianqian Xu
- Department of Laboratory Medicine, Huashan Hospital, Fudan University, Shanghai, 200040, PR China
| | - Jianfei Gu
- Department of Laboratory Medicine, Huashan Hospital, Fudan University, Shanghai, 200040, PR China
| | - Zhihua Kang
- Department of Radiation Oncology, Rutgers Cancer Institute of New Jersey, Rutgers University, New Brunswick, USA
| | - Jian Chen
- Department of Laboratory Medicine, Huashan Hospital, Fudan University, Shanghai, 200040, PR China
| | - Xiao Xu
- Central Laboratory, Huashan Hospital, Fudan University, Shanghai, PR China
| | - Xinju Zhang
- Central Laboratory, Huashan Hospital, Fudan University, Shanghai, PR China
| | - Xiuming Zhang
- Medical Laboratory of Shenzhen Luohu Hospital Group, Shenzhen Luohu People's Hospital, Shenzhen, PR China.
| | - Haoqin Jiang
- Department of Laboratory Medicine, Huashan Hospital, Fudan University, Shanghai, 200040, PR China.
| | - Ming Guan
- Department of Laboratory Medicine, Huashan Hospital, Fudan University, Shanghai, 200040, PR China.
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10
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Oduma CO, Ombok M, Zhao X, Huwe T, Ondigo BN, Kazura JW, Grieco J, Achee N, Liu F, Ochomo E, Koepfli C. Altitude, not potential larval habitat availability, explains pronounced variation in Plasmodium falciparum infection prevalence in the western Kenya highlands. PLOS GLOBAL PUBLIC HEALTH 2023; 3:e0001505. [PMID: 37068071 PMCID: PMC10109483 DOI: 10.1371/journal.pgph.0001505] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/21/2022] [Accepted: 03/03/2023] [Indexed: 04/18/2023]
Abstract
Progress in malaria control has stalled over the recent years. Knowledge on main drivers of transmission explaining small-scale variation in prevalence can inform targeted control measures. We collected finger-prick blood samples from 3061 individuals irrespective of clinical symptoms in 20 clusters in Busia in western Kenya and screened for Plasmodium falciparum parasites using qPCR and microscopy. Clusters spanned an altitude range of 207 meters (1077-1284 m). We mapped potential mosquito larval habitats and determined their number within 250 m of a household and distances to households using ArcMap. Across all clusters, P. falciparum parasites were detected in 49.8% (1524/3061) of individuals by qPCR and 19.5% (596/3061) by microscopy. Across the clusters, prevalence ranged from 26% to 70% by qPCR. Three to 34 larval habitats per cluster and 0-17 habitats within a 250m radius around households were observed. Using a generalized linear mixed effect model (GLMM), a 5% decrease in the odds of getting infected per each 10m increase in altitude was observed, while the number of larval habitats and their proximity to households were not statistically significant predictors for prevalence. Kitchen located indoors, open eaves, a lower level of education of the household head, older age, and being male were significantly associated with higher prevalence. Pronounced variation in prevalence at small scales was observed and needs to be taken into account for malaria surveillance and control. Potential larval habitat frequency had no direct impact on prevalence.
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Affiliation(s)
- Colins O Oduma
- Department of Biochemistry and Molecular Biology, Egerton University, Nakuru, Kenya
- Kenya Medical Research Institute, Centre for Global Health Research, Kisumu, Kenya
| | - Maurice Ombok
- Kenya Medical Research Institute, Centre for Global Health Research, Kisumu, Kenya
| | - Xingyuan Zhao
- Department of Applied and Computational Mathematics and Statistics, University of Notre Dame, Notre Dame, IN, United States of America
| | - Tiffany Huwe
- Department of Biological Sciences and Eck Institute for Global Health, University of Notre Dame, Notre Dame, IN, United States of America
| | - Bartholomew N Ondigo
- Department of Biochemistry and Molecular Biology, Egerton University, Nakuru, Kenya
- Kenya Medical Research Institute, Centre for Global Health Research, Kisumu, Kenya
| | - James W Kazura
- Case Western Reserve University, Center for Global Health and Diseases, Cleveland, OH, United States of America
| | - John Grieco
- Department of Biological Sciences and Eck Institute for Global Health, University of Notre Dame, Notre Dame, IN, United States of America
| | - Nicole Achee
- Department of Biological Sciences and Eck Institute for Global Health, University of Notre Dame, Notre Dame, IN, United States of America
| | - Fang Liu
- Department of Applied and Computational Mathematics and Statistics, University of Notre Dame, Notre Dame, IN, United States of America
- Department of Biological Sciences and Eck Institute for Global Health, University of Notre Dame, Notre Dame, IN, United States of America
| | - Eric Ochomo
- Kenya Medical Research Institute, Centre for Global Health Research, Kisumu, Kenya
| | - Cristian Koepfli
- Department of Biological Sciences and Eck Institute for Global Health, University of Notre Dame, Notre Dame, IN, United States of America
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11
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Roberds A, Kifude C, Oyieko J, Ocholla S, Mutunga J, Oullo D, Waga C, Li Z, Luckhart S, Stewart VA. Longitudinal impact of asymptomatic malaria/HIV-1 co-infection on Plasmodium falciparum gametocyte transcript expression and transmission to Anopheles mosquitoes. Front Cell Infect Microbiol 2022; 12:934641. [PMID: 36189366 PMCID: PMC9523792 DOI: 10.3389/fcimb.2022.934641] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2022] [Accepted: 08/25/2022] [Indexed: 11/28/2022] Open
Abstract
Despite significant developments towards malaria reduction, parasite transmission in the common context of HIV-1 co-infection and treatment for one or both infections has not been fully characterized. This is particularly important given that HIV-1 and malaria chemotherapies have the potential to alter gametocyte burden and mosquito infectivity. In this study, we examined 782 blood samples collected from a longitudinal cohort of 300 volunteers with asymptomatic parasitemia seeking HIV testing or treatment in the endemic region of Kisumu, Kenya, to define the impacts of HIV-1-malaria co-infection, antiretroviral therapy (ART) plus trimethoprim-sulfamethoxazole (TS) and the antimalarials artemether/lumefantrine (AL) on Plasmodium falciparum gametocyte transcript prevalence and parasite transmission to the African malaria mosquito Anopheles gambiae. Volunteers were assigned to three distinct HIV-1 groups: HIV-1 positive on treatment, HIV-1 positive newly diagnosed, and HIV-1 negative. Volunteers were monitored monthly over the course of six months. Using our highly sensitive digital droplet PCR (ddPCR) assay of three gametocyte specific transcript markers, we detected gametocyte transcripts in 51.1% of 18S positive volunteers across all study groups and time points. After correcting for multiple comparisons, the factors of HIV-1 status, time, CD4+ T-cell levels and hematocrit were not predictive of gametocyte prevalence or transmission. However, among those volunteers who were newly diagnosed with HIV-1 and malaria positive by rapid diagnostic test (RDT) at enrollment, the initiation of ART/TS and AL treatment was associated with a significant reduction in gametocyte transcript prevalence in the subsequent month when compared to HIV-1 negative volunteers treated with AL. To assess gametocyte transmissibility, volunteer blood samples were used in standard membrane feeding assays (SFMA) with laboratory-reared A. gambiae, with evidence of transmission confirmed by at least one of 25 dissected mosquitoes per sample positive for at least one midgut oocyst. HIV-1 status, CD4+ T-cell levels and hematocrit were not significantly associated with successful transmission to A. gambiae. Analysis of SMFA blood samples revealed that 50% of transmission-positive blood samples failed to test positive by Plasmodium-specific 18S ribosomal RNA quantitative PCR (qPCR) and 35% failed to test positive for any gametocyte specific transcript marker by droplet digital (ddPCR), documenting that transmission occurred in the absence of molecular parasite/gametocyte detection. Overall, these findings highlight the complexity of HIV-1 malaria co-infection and the need to further define the unpredictable role of asymptomatic parasitemia in transmission to mosquitoes.
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Affiliation(s)
- Ashleigh Roberds
- Department of Preventive Medicine and Biostatistics, Division of Global Public Health, Uniformed Services University of the Health Sciences, Bethesda, MD, United States
- *Correspondence: Ashleigh Roberds,
| | - Carolyne Kifude
- Kombewa Clinical Research Center, Kenya Medical Research Institute - United States Army Medical Research Directorate - Africa, Kisumu, Kenya
| | - Janet Oyieko
- Kombewa Clinical Research Center, Kenya Medical Research Institute - United States Army Medical Research Directorate - Africa, Kisumu, Kenya
| | - Stephen Ocholla
- Kombewa Clinical Research Center, Kenya Medical Research Institute - United States Army Medical Research Directorate - Africa, Kisumu, Kenya
| | - James Mutunga
- Department of Entomology and Vector Biology, United States Army Medical Research Directorate - Africa/Kenya Medical Research Institute, Kisumu, Kenya
- Department of Biological Sciences, Mount Kenya University, Thika, Kenya
| | - David Oullo
- Department of Entomology and Vector Biology, United States Army Medical Research Directorate - Africa/Kenya Medical Research Institute, Kisumu, Kenya
| | - Charles Waga
- Department of Entomology and Vector Biology, United States Army Medical Research Directorate - Africa/Kenya Medical Research Institute, Kisumu, Kenya
| | - Zhaozhang Li
- Biomedical Instrumentation Center, Uniformed Services University of the Health Sciences, Bethesda, MD, United States
| | - Shirley Luckhart
- Department of Entomology, Plant Pathology and Nematology and Department of Biological Sciences, University of Idaho, Moscow, ID, United States
| | - V. Ann Stewart
- Department of Preventive Medicine and Biostatistics, Division of Global Public Health, Uniformed Services University of the Health Sciences, Bethesda, MD, United States
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12
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Vera-Arias CA, Holzschuh A, Oduma CO, Badu K, Abdul-Hakim M, Yukich J, Hetzel MW, Fakih BS, Ali A, Ferreira MU, Ladeia-Andrade S, Sáenz FE, Afrane Y, Zemene E, Yewhalaw D, Kazura JW, Yan G, Koepfli C. High-throughput Plasmodium falciparum hrp2 and hrp3 gene deletion typing by digital PCR to monitor malaria rapid diagnostic test efficacy. eLife 2022; 11:72083. [PMID: 35762586 PMCID: PMC9246365 DOI: 10.7554/elife.72083] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2021] [Accepted: 06/05/2022] [Indexed: 01/11/2023] Open
Abstract
Most rapid diagnostic tests for Plasmodium falciparum malaria target the Histidine-Rich Proteins 2 and 3 (HRP2 and HRP3). Deletions of the hrp2 and hrp3 genes result in false-negative tests and are a threat for malaria control. A novel assay for molecular surveillance of hrp2/hrp3 deletions was developed based on droplet digital PCR (ddPCR). The assay quantifies hrp2, hrp3, and a control gene with very high accuracy. The theoretical limit of detection was 0.33 parasites/µl. The deletion was reliably detected in mixed infections with wild-type and hrp2-deleted parasites at a density of >100 parasites/reaction. For a side-by-side comparison with the conventional nested PCR (nPCR) assay, 248 samples were screened in triplicate by ddPCR and nPCR. No deletions were observed by ddPCR, while by nPCR hrp2 deletion was observed in 8% of samples. The ddPCR assay was applied to screen 830 samples from Kenya, Zanzibar/Tanzania, Ghana, Ethiopia, Brazil, and Ecuador. Pronounced differences in the prevalence of deletions were observed among sites, with more hrp3 than hrp2 deletions. In conclusion, the novel ddPCR assay minimizes the risk of false-negative results (i.e., hrp2 deletion observed when the sample is wild type), increases sensitivity, and greatly reduces the number of reactions that need to be run.
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Affiliation(s)
| | - Aurel Holzschuh
- University of Notre Dame, Notre Dame, United States.,Swiss Tropical and Public Health Institute, Allschwil, Switzerland
| | - Colins O Oduma
- Kenya Medical Research Institute-Centre for Global Health Research, Kisumu, Kenya.,Department of Biochemistry and Molecular Biology, Egerton University, Nakuru, Kenya
| | - Kingsley Badu
- Kwame Nkrumah University of Science and Technology, Kumasi, Ghana
| | | | | | - Manuel W Hetzel
- Swiss Tropical and Public Health Institute, Allschwil, Switzerland.,University of Basel, Basel, Switzerland
| | - Bakar S Fakih
- Swiss Tropical and Public Health Institute, Allschwil, Switzerland.,University of Basel, Basel, Switzerland.,Ifakara Health Institute, Dar es Salaam, United Republic of Tanzania
| | - Abdullah Ali
- Zanzibar Malaria Elimination Programme, Zanzibar, Zanzibar, United Republic of Tanzania
| | | | | | - Fabián E Sáenz
- Centro de Investigación para la Salud en América Latina, Facultad de Ciencias Exactas y Naturales, Pontificia Universidad Católica del Ecuador, Quito, Ecuador
| | - Yaw Afrane
- Department of Medical Microbiology, University of Ghana, Accra, Ghana
| | - Endalew Zemene
- Tropical and Infectious Diseases Research Center, Jimma University, Jimma, Ethiopia
| | - Delenasaw Yewhalaw
- Tropical and Infectious Diseases Research Center, Jimma University, Jimma, Ethiopia
| | - James W Kazura
- Case Western Reserve University, Cleveland, United States
| | - Guiyun Yan
- Program in Public Health, University of California, Irvine, Irvine, United States
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13
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Costa GL, Alvarenga DAM, Aguiar ACC, Louzada J, Pereira DB, de Oliveira TF, Fonseca Júnior AA, Carvalho LH, Ferreira Alves de Brito C, Nóbrega de Sousa T. Improving the Molecular Diagnosis of Malaria: Droplet Digital PCR-Based Method Using Saliva as a DNA Source. Front Microbiol 2022; 13:882530. [PMID: 35633683 PMCID: PMC9136408 DOI: 10.3389/fmicb.2022.882530] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2022] [Accepted: 04/20/2022] [Indexed: 12/20/2022] Open
Abstract
Malaria is an acute febrile disease caused by a protozoan of the genus Plasmodium. Light microscopy (LM) is the gold standard for the diagnosis of malaria. Despite this method being rapid and inexpensive, it has a low limit of detection, which hampers the identification of low parasitemia infections. By using multicopy targets and highly sensitive molecular techniques, it is possible to change this scenario. In this study, we evaluated the performance of droplet digital PCR (ddPCR) to detect Plasmodium DNA obtained from saliva samples (whole saliva and buccal swab) of 157 individuals exposed to malaria transmission from the Brazilian Amazon region. We used the highly sensitive ddPCR method with non-ribosomal multicopy targets for Plasmodium vivax (Pvr47) and Plasmodium falciparum (Pfr364). There was good concordance between the quantitative real-time PCR (qPCR) results from the saliva and blood, except for mixed-species infections. The sensitivity of qPCR was 93% for blood, 77% for saliva, and 47% for swabs. Parasite DNA was not detected in saliva samples in low-density infections compared with the detection in blood samples. ddPCR showed increased sensitivity for detecting Plasmodium in the blood and swabs (99% in blood, 73% in saliva, and 59% in swabs). Notably, ddPCR detected more mixed infections in the blood (15%), saliva (9%), and swabs (18%) than qPCR. Our data showed that the differences between ddPCR and qPCR were the result of a higher number of P. falciparum infections detected by ddPCR. Overall, there was a moderate correlation between parasite densities estimated by the different methods in the blood. Our findings highlight the possibility of using non-invasive sample collection methods for malaria diagnosis by targeting multicopy sequences combined with highly sensitive molecular methods.
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Affiliation(s)
- Gabriel Luíz Costa
- Molecular Biology and Malaria Immunology Research Group, Instituto René Rachou, Fundação Oswaldo Cruz (FIOCRUZ), Belo Horizonte, Brazil
| | - Denise Anete Madureira Alvarenga
- Molecular Biology and Malaria Immunology Research Group, Instituto René Rachou, Fundação Oswaldo Cruz (FIOCRUZ), Belo Horizonte, Brazil
| | | | - Jaime Louzada
- Health Sciences Center, Federal University of Roraima, Boa Vista, Brazil
| | | | | | | | - Luzia Helena Carvalho
- Molecular Biology and Malaria Immunology Research Group, Instituto René Rachou, Fundação Oswaldo Cruz (FIOCRUZ), Belo Horizonte, Brazil
| | - Cristiana Ferreira Alves de Brito
- Molecular Biology and Malaria Immunology Research Group, Instituto René Rachou, Fundação Oswaldo Cruz (FIOCRUZ), Belo Horizonte, Brazil
| | - Taís Nóbrega de Sousa
- Molecular Biology and Malaria Immunology Research Group, Instituto René Rachou, Fundação Oswaldo Cruz (FIOCRUZ), Belo Horizonte, Brazil
- *Correspondence: Taís Nóbrega de Sousa
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14
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Lee WC, Cheong FW, Amir A, Lai MY, Tan JH, Phang WK, Shahari S, Lau YL. Plasmodium knowlesi: the game changer for malaria eradication. Malar J 2022; 21:140. [PMID: 35505339 PMCID: PMC9066973 DOI: 10.1186/s12936-022-04131-8] [Citation(s) in RCA: 19] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2021] [Accepted: 03/18/2022] [Indexed: 11/12/2022] Open
Abstract
Plasmodium knowlesi is a zoonotic malaria parasite that has gained increasing medical interest over the past two decades. This zoonotic parasitic infection is prevalent in Southeast Asia and causes many cases with fulminant pathology. Despite several biogeographical restrictions that limit its distribution, knowlesi malaria cases have been reported in different parts of the world due to travelling and tourism activities. Here, breakthroughs and key information generated from recent (over the past five years, but not limited to) studies conducted on P. knowlesi were reviewed, and the knowledge gap in various research aspects that need to be filled was discussed. Besides, challenges and strategies required to control and eradicate human malaria with this emerging and potentially fatal zoonosis were described.
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Affiliation(s)
- Wenn-Chyau Lee
- Department of Parasitology, Faculty of Medicine, Universiti Malaya, Kuala Lumpur, Malaysia
| | - Fei Wen Cheong
- Department of Parasitology, Faculty of Medicine, Universiti Malaya, Kuala Lumpur, Malaysia
| | - Amirah Amir
- Department of Parasitology, Faculty of Medicine, Universiti Malaya, Kuala Lumpur, Malaysia
| | - Meng Yee Lai
- Department of Parasitology, Faculty of Medicine, Universiti Malaya, Kuala Lumpur, Malaysia
| | - Jia Hui Tan
- Department of Parasitology, Faculty of Medicine, Universiti Malaya, Kuala Lumpur, Malaysia
| | - Wei Kit Phang
- Department of Parasitology, Faculty of Medicine, Universiti Malaya, Kuala Lumpur, Malaysia
| | - Shahhaziq Shahari
- Department of Parasitology, Faculty of Medicine, Universiti Malaya, Kuala Lumpur, Malaysia
| | - Yee-Ling Lau
- Department of Parasitology, Faculty of Medicine, Universiti Malaya, Kuala Lumpur, Malaysia.
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15
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Wichianchot S, Hongsrichan N, Maneeruttanarungroj C, Pinlaor S, Iamrod K, Purisarn A, Donthaisong P, Karanis P, Nimsuphan B, Rucksaken R. A newly developed droplet digital PCR for Ehrlichia canis detection: comparisons to conventional PCR and blood smear techniques. J Vet Med Sci 2022; 84:831-840. [PMID: 35473801 PMCID: PMC9246678 DOI: 10.1292/jvms.22-0086] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Canine monocytic ehrlichiosis caused by Ehrlichia canis infection is a life-threatening vector-borne disease in dogs worldwide. Routine blood smear has very low sensitivity and cannot accurately provide a quantitative result. Conventional PCR (cPCR) and real-time PCR (qPCR) are widely used as molecular methods for E. canis detection. qPCR is quantitative but relies on standard curves of known samples. To overcome this difficulty, this study developed a new E. canis quantitative detection method, using droplet digital polymerase chain reaction (ddPCR). ddPCR was evaluated against cPCR and blood smears. PCR amplicons and genomic DNA (gDNA) from 12 microscopic positive samples were used to identify the limits of detection (LODs) in ddPCR and cPCR. Our ddPCR was assessed in 92 field samples, it was compared with cPCR and blood smears. ddPCR showed LOD = 1.6 copies/reaction, or 78 times more sensitive than cPCR (LOD = 126 copies/reaction), using PCR amplicons as a template, whereas both ddPCR and cPCR had equal LODs at 0.02 ng gDNA/reaction. In addition, ddPCR had 100% sensitivity and 75% specificity for E. canis detection compared to cPCR and no cross-reaction with other blood pathogens was observed. ddPCR identified more positive samples than cPCR and blood smear. ddPCR improved the overall performance of E. canis detection, with a better LOD and comparable sensitivity and specificity to cPCR. The technique might be helpful for diagnosis of E. canis in light infection, evaluating the number of E. canis and follow-up after treatment.
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Affiliation(s)
- Sakulchit Wichianchot
- Department of Veterinary Technology, Faculty of Veterinary Technology, Kasetsart University
| | | | - Cherdsak Maneeruttanarungroj
- Department of Biology, School of Science, King Mongkut's Institute of Technology Ladkrabang.,Bioenergy Research Unit, School of Science, King Mongkut's Institute of Technology Ladkrabang
| | - Somchai Pinlaor
- Department of Parasitology, Faculty of Medicine, Khon Kaen University
| | - Kantapong Iamrod
- Department of Parasitology, Faculty of Medicine, Khon Kaen University
| | - Andaman Purisarn
- Department of Veterinary Technology, Faculty of Veterinary Technology, Kasetsart University
| | - Peerawich Donthaisong
- Department of Veterinary Technology, Faculty of Veterinary Technology, Kasetsart University
| | - Panagiotis Karanis
- University of Cologne, Medical Faculty and University Hospital Cologne.,University of Nicosia Medical School, Department of Basic and Clinical Sciences
| | - Burin Nimsuphan
- Department of Parasitology, Faculty of Veterinary Medicine, Kasetsart University
| | - Rucksak Rucksaken
- Department of Veterinary Technology, Faculty of Veterinary Technology, Kasetsart University
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16
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Mpina M, Stabler TC, Schindler T, Raso J, Deal A, Acuche Pupu L, Nyakarungu E, Del Carmen Ovono Davis M, Urbano V, Mtoro A, Hamad A, Lopez MSA, Pasialo B, Eyang MAO, Rivas MR, Falla CC, García GA, Momo JC, Chuquiyauri R, Saverino E, Preston Church LW, Kim Lee Sim B, Manguire B, Tanner M, Maas C, Abdulla S, Billingsley PF, Hoffman SL, Jongo S, Richie TL, Daubenberger CA. Diagnostic performance and comparison of ultrasensitive and conventional rapid diagnostic test, thick blood smear and quantitative PCR for detection of low-density Plasmodium falciparum infections during a controlled human malaria infection study in Equatorial Guinea. Malar J 2022; 21:99. [PMID: 35331251 PMCID: PMC8943516 DOI: 10.1186/s12936-022-04103-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2021] [Accepted: 02/23/2022] [Indexed: 12/02/2022] Open
Abstract
Background Progress towards malaria elimination has stagnated, partly because infections persisting at low parasite densities comprise a large reservoir contributing to ongoing malaria transmission and are difficult to detect. This study compared the performance of an ultrasensitive rapid diagnostic test (uRDT) designed to detect low density infections to a conventional RDT (cRDT), expert microscopy using Giemsa-stained thick blood smears (TBS), and quantitative polymerase chain reaction (qPCR) during a controlled human malaria infection (CHMI) study conducted in malaria exposed adults (NCT03590340). Methods Blood samples were collected from healthy Equatoguineans aged 18–35 years beginning on day 8 after CHMI with 3.2 × 103 cryopreserved, infectious Plasmodium falciparum sporozoites (PfSPZ Challenge, strain NF54) administered by direct venous inoculation. qPCR (18s ribosomal DNA), uRDT (Alere™ Malaria Ag P.f.), cRDT [Carestart Malaria Pf/PAN (PfHRP2/pLDH)], and TBS were performed daily until the volunteer became TBS positive and treatment was administered. qPCR was the reference for the presence of Plasmodium falciparum parasites. Results 279 samples were collected from 24 participants; 123 were positive by qPCR. TBS detected 24/123 (19.5% sensitivity [95% CI 13.1–27.8%]), uRDT 21/123 (17.1% sensitivity [95% CI 11.1–25.1%]), cRDT 10/123 (8.1% sensitivity [95% CI 4.2–14.8%]); all were 100% specific and did not detect any positive samples not detected by qPCR. TBS and uRDT were more sensitive than cRDT (TBS vs. cRDT p = 0.015; uRDT vs. cRDT p = 0.053), detecting parasitaemias as low as 3.7 parasites/µL (p/µL) (TBS and uRDT) compared to 5.6 p/µL (cRDT) based on TBS density measurements. TBS, uRDT and cRDT did not detect any of the 70/123 samples positive by qPCR below 5.86 p/µL, the qPCR density corresponding to 3.7 p/µL by TBS. The median prepatent periods in days (ranges) were 14.5 (10–20), 18.0 (15–28), 18.0 (15–20) and 18.0 (16–24) for qPCR, TBS, uRDT and cRDT, respectively; qPCR detected parasitaemia significantly earlier (3.5 days) than the other tests. Conclusions TBS and uRDT had similar sensitivities, both were more sensitive than cRDT, and neither matched qPCR for detecting low density parasitaemia. uRDT could be considered an alternative to TBS in selected applications, such as CHMI or field diagnosis, where qualitative, dichotomous results for malaria infection might be sufficient. Supplementary Information The online version contains supplementary material available at 10.1186/s12936-022-04103-y.
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Affiliation(s)
- Maxmillian Mpina
- Swiss Tropical and Public Health Institute, Basel, Switzerland. .,University of Basel, Basel, Switzerland. .,Ifakara Health Institute, Ifakara, Tanzania.
| | - Thomas C Stabler
- Swiss Tropical and Public Health Institute, Basel, Switzerland.,University of Basel, Basel, Switzerland
| | - Tobias Schindler
- Swiss Tropical and Public Health Institute, Basel, Switzerland.,University of Basel, Basel, Switzerland
| | - Jose Raso
- Medical Care Development International, Malabo, Equatorial Guinea.,Equatorial Guinea Ministry of Health and Social Welfare, Malabo, Equatorial Guinea
| | - Anna Deal
- Swiss Tropical and Public Health Institute, Basel, Switzerland.,University of Basel, Basel, Switzerland
| | | | - Elizabeth Nyakarungu
- Ifakara Health Institute, Ifakara, Tanzania.,Medical Care Development International, Malabo, Equatorial Guinea
| | | | - Vicente Urbano
- Medical Care Development International, Malabo, Equatorial Guinea.,Equatorial Guinea Ministry of Health and Social Welfare, Malabo, Equatorial Guinea
| | - Ali Mtoro
- Ifakara Health Institute, Ifakara, Tanzania.,Medical Care Development International, Malabo, Equatorial Guinea
| | - Ali Hamad
- Ifakara Health Institute, Ifakara, Tanzania.,Medical Care Development International, Malabo, Equatorial Guinea
| | - Maria Silvia A Lopez
- Medical Care Development International, Malabo, Equatorial Guinea.,Equatorial Guinea Ministry of Health and Social Welfare, Malabo, Equatorial Guinea
| | - Beltran Pasialo
- Medical Care Development International, Malabo, Equatorial Guinea.,Equatorial Guinea Ministry of Health and Social Welfare, Malabo, Equatorial Guinea
| | - Marta Alene Owono Eyang
- Medical Care Development International, Malabo, Equatorial Guinea.,Equatorial Guinea Ministry of Health and Social Welfare, Malabo, Equatorial Guinea
| | - Matilde Riloha Rivas
- Equatorial Guinea Ministry of Health and Social Welfare, Malabo, Equatorial Guinea
| | | | | | - Juan Carlos Momo
- Medical Care Development International, Malabo, Equatorial Guinea.,Equatorial Guinea Ministry of Health and Social Welfare, Malabo, Equatorial Guinea
| | - Raul Chuquiyauri
- Medical Care Development International, Malabo, Equatorial Guinea.,Sanaria Inc., 9800 Medical Center Drive, Rockville, MD, 20850, USA
| | | | | | - B Kim Lee Sim
- Sanaria Inc., 9800 Medical Center Drive, Rockville, MD, 20850, USA
| | | | - Marcel Tanner
- Swiss Tropical and Public Health Institute, Basel, Switzerland.,University of Basel, Basel, Switzerland
| | - Carl Maas
- Marathon EG production Ltd., Houston, USA
| | | | | | | | - Said Jongo
- Ifakara Health Institute, Ifakara, Tanzania.,Medical Care Development International, Malabo, Equatorial Guinea
| | - Thomas L Richie
- Sanaria Inc., 9800 Medical Center Drive, Rockville, MD, 20850, USA
| | - Claudia A Daubenberger
- Swiss Tropical and Public Health Institute, Basel, Switzerland. .,University of Basel, Basel, Switzerland.
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17
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Groen K, Trimbos KB, Hein S, Blaauw AI, van Bodegom PM, Hahne J, Jacob J. Establishment of a fecal DNA quantification technique for rare and cryptic diet constituents in small mammals. Mol Ecol Resour 2022; 22:2220-2231. [PMID: 35297564 DOI: 10.1111/1755-0998.13609] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2021] [Revised: 02/25/2022] [Accepted: 03/04/2022] [Indexed: 11/27/2022]
Abstract
DNA-based approaches have highly improved the applicability of dietary studies aimed at investigating ecological processes. These studies have provided direct insights into, otherwise difficult to measure, interactions between species and trophic levels, food web structure and ecosystem functioning. However, despite these advances, DNA-based methods have been struggling to accurately quantify the whole breadth of diet constituents because of methodological biases, such as amplification bias and digestive processes. This study is, to our knowledge, the first diet study that used droplet digital PCR to quantify diet constituents. We manipulated the diet of wild caught wood mice (Apodemus sylvaticus) by feeding them with a known amount of small vegetable seeds (onion and carrot) and quantified the DNA traces of these diet constituents in fecal samples. The sensitivity of the technique combined with the control on the experimental design allowed mitigation of methodological bias. We were able to accurately determine DNA concentrations of small vegetable seeds in the diet of wood mice. Quantification of target DNA demonstrated significant differences in DNA content when one vs. five seeds were consumed. These differences remained significant when the age, sex, and other diet constituents of the mice were altered. Different DNA markers, targeting different parts of the chloroplast, influenced onion DNA detectability. However, all onion and carrot markers showed higher DNA content for higher seed numbers. Overall, the sensitive DNA based approach developed in this study allows for minimally-invasive quantification of small diet constituents in feces, which would otherwise be undetectable with traditional methods.
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Affiliation(s)
- Kevin Groen
- Environmental Biology, Institute of Environmental Sciences, Leiden University, Leiden, Van Steenis Building Einsteinweg 2, 2333 CC, The Netherlands
| | - Krijn B Trimbos
- Environmental Biology, Institute of Environmental Sciences, Leiden University, Leiden, Van Steenis Building Einsteinweg 2, 2333 CC, The Netherlands
| | - Susanne Hein
- Vertebrate Research, Institute for Plant Protection in Horticulture and Forests, Julius Kühn-Institute (JKI) Federal Research Institute for Cultivated Plants, Toppheideweg 88, 48161, Münster, Germany.,Present address: BASF SE, Agricultural Solutions - Global Ecotoxicology, Limburgerhof, Germany
| | - Astrid I Blaauw
- Environmental Biology, Institute of Environmental Sciences, Leiden University, Leiden, Van Steenis Building Einsteinweg 2, 2333 CC, The Netherlands
| | - Peter M van Bodegom
- Environmental Biology, Institute of Environmental Sciences, Leiden University, Leiden, Van Steenis Building Einsteinweg 2, 2333 CC, The Netherlands
| | - Joerg Hahne
- Bayer AG, Crop Science Division, Terrestrial Vertebrates, Monheim am Rhein, Germany
| | - Jens Jacob
- Vertebrate Research, Institute for Plant Protection in Horticulture and Forests, Julius Kühn-Institute (JKI) Federal Research Institute for Cultivated Plants, Toppheideweg 88, 48161, Münster, Germany
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18
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Tenfold difference in DNA recovery rate: systematic comparison of whole blood vs. dried blood spot sample collection for malaria molecular surveillance. Malar J 2022; 21:88. [PMID: 35292038 PMCID: PMC8922754 DOI: 10.1186/s12936-022-04122-9] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2022] [Accepted: 03/07/2022] [Indexed: 02/06/2023] Open
Abstract
BACKGROUND Molecular and genomic surveillance is becoming increasingly used to track malaria control and elimination efforts. Blood samples can be collected as whole blood and stored at - 20 °C until DNA extraction, or as dried blood spots (DBS), circumventing the need for a cold chain. Despite the wide use of either method, systematic comparisons of how the method of blood sample preservation affects the limit of detection (LOD) of molecular diagnosis and the proportion of DNA recovered for downstream applications are lacking. METHODS Extractions based on spin columns, magnetic beads, Tween-Chelex, and direct PCR without prior extraction were compared for whole blood and dried blood spots (DBS) using dilution series of Plasmodium falciparum culture samples. Extracted DNA was quantified by qPCR and droplet digital PCR (ddPCR). RESULTS DNA recovery was 5- to 10-fold higher for whole blood compared to DBS, resulting in a 2- to 3-fold lower LOD for both extraction methods compared to DBS. For whole blood, a magnetic bead-based method resulted in a DNA recovery rate of 88-98% when extracting from whole blood compared to 17-33% for a spin-column based method. For extractions from DBS, the magnetic bead-based method resulted in 8-20% DNA recovery, while the spin-column based method resulted in only 2% DNA recovery. The Tween-Chelex method was superior to other methods with 15-21% DNA recovery, and even more sensitive than extractions from whole blood samples. The direct PCR method was found to have the lowest LOD overall for both, whole blood and DBS. CONCLUSIONS Pronounced differences in LOD and DNA yield need to be considered when comparing prevalence estimates based on molecular methods and when selecting sampling protocols for other molecular surveillance applications.
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Tan LL, Loganathan N, Agarwalla S, Yang C, Yuan W, Zeng J, Wu R, Wang W, Duraiswamy S. Current commercial dPCR platforms: technology and market review. Crit Rev Biotechnol 2022; 43:433-464. [PMID: 35291902 DOI: 10.1080/07388551.2022.2037503] [Citation(s) in RCA: 37] [Impact Index Per Article: 18.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Digital polymerase chain reaction (dPCR) technology has provided a new technique for molecular diagnostics, with superior advantages, such as higher sensitivity, precision, and specificity over quantitative real-time PCRs (qPCR). Eight companies have offered commercial dPCR instruments: Fluidigm Corporation, Bio-Rad, RainDance Technologies, Life Technologies, Qiagen, JN MedSys Clarity, Optolane, and Stilla Technologies Naica. This paper discusses the working principle of each offered dPCR device and compares the associated: technical aspects, usability, costs, and current applications of each dPCR device. Lastly, up-and-coming dPCR technologies are also presented, as anticipation of how the dPCR device landscape may likely morph in the next few years.
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Affiliation(s)
- Li Ling Tan
- Singapore Institute of Manufacturing Technology, Singapore, Singapore.,Materials Science and Engineering School, Nanyang Technological University, Singapore, Singapore
| | - Nitin Loganathan
- Singapore Institute of Manufacturing Technology, Singapore, Singapore
| | - Sushama Agarwalla
- Department of Chemical Engineering, Indian Institute of Technology Hyderabad, Hyderabad, India
| | - Chun Yang
- Mechanical and Aerospace Engineering School, Nanyang Technological University, Singapore, Singapore
| | - Weiyong Yuan
- Faculty of Materials & Energy, Institute for Clean Energy and Advanced Materials, Southwest University, Chongqing, China.,Chongqing Key Laboratory for Advanced Materials and Technologies of Clean Energies, Chongqing, China
| | - Jasmine Zeng
- Singapore Institute of Manufacturing Technology, Singapore, Singapore
| | - Ruige Wu
- Singapore Institute of Manufacturing Technology, Singapore, Singapore
| | - Wei Wang
- Singapore Institute of Manufacturing Technology, Singapore, Singapore
| | - Suhanya Duraiswamy
- Department of Chemical Engineering, Indian Institute of Technology Hyderabad, Hyderabad, India
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20
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Zhao Y, Zhao Y, Sun Y, Fan L, Wang D, Wang H, Sun X, Zheng Z. A direct, sensitive and high-throughput genus and species-specific molecular assay for large-scale malaria screening. Infect Dis Poverty 2022; 11:25. [PMID: 35255983 PMCID: PMC8900325 DOI: 10.1186/s40249-022-00948-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2021] [Accepted: 02/17/2022] [Indexed: 12/26/2022] Open
Abstract
Background Infectious disease diagnostics often requires sensitive molecular assays that identify at both genus and species levels. For large scale screening, such as malaria screening for elimination, diagnostic assay can be a challenge, as both the throughput and cost of the assay must be considered. The requirement of nucleic acid extraction hampers the throughput of most molecular assays. Co-amplification of multiple species or multiplex identification either can result in missed diagnosis or are too costly for large-scale screening. A genus- and species-specific diagnostic assay with simplified procedure, high sensitivity and throughput is still needed. This study aimed to develop a sensitive and high-throughput approach for large-scale infectious disease screening. Methods We developed multi-section Capture and Ligation Probe PCR (mCLIP-PCR) for the direct detection of RNA without extraction and reverse transcription. Multiple tailed sandwich hybridization probes were used to bind at genus- and species-specific sections of the target RNA to cooperatively capture the target onto a 96-well plate. After enzymatic ligation of the bound probes, a single-stranded DNA formed at each section with distinct tail sequence at the ends. They were separately PCR-amplified with primers corresponding to tail sequences for genus or species identification. We applied the method to the active screening of Plasmodium infections of 4,580 asymptomatic dried blood spot samples collected in malaria endemic areas and compared the results with standard qPCR using linear regression. Results With multi-section cooperative capture but separate amplification strategy, we accurately identified genus Plasmodium and species P. falciparum and P. vivax without RNA extraction, with favorable sensitivities among the published reports. In the active screening, our method identified all 53 positive infections including two mixed infections, and two P. vivax infections that were missed by standard qPCR. Conclusions mCLIP-PCR provides a sensitive and high-throughput approach to large-scale infectious disease screening with low cost and labor, making it a valuable tool for malaria elimination in endemic region. Graphical Abstract ![]()
Supplementary Information The online version contains supplementary material available at 10.1186/s40249-022-00948-2.
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21
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Fitri LE, Widaningrum T, Endharti AT, Prabowo MH, Winaris N, Nugraha RYB. Malaria diagnostic update: From conventional to advanced method. J Clin Lab Anal 2022; 36:e24314. [PMID: 35247002 PMCID: PMC8993657 DOI: 10.1002/jcla.24314] [Citation(s) in RCA: 22] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2020] [Revised: 02/11/2022] [Accepted: 02/16/2022] [Indexed: 01/12/2023] Open
Abstract
BACKGROUND Update diagnostic methods play essential roles in dealing with the current global malaria situation and decreasing malaria incidence. AIM Global malaria control programs require the availability of adequate laboratory tests in the quick and convenient field. RESULTS There are several methods to find out the existence of parasites within the blood. The oldest one is by microscopy, which is still a gold standard, although rapid diagnostic tests (RDTs) have rapidly become a primary diagnostic test in many endemic areas. Because of microscopy and RDTs limitation, novel serological and molecular methods have been developed. Many kinds of polymerase chain reaction (PCR) provide rapid results and higher specificity and sensitivity. The loop-mediated isothermal amplification (LAMP) and biosensing-based molecular techniques as point of care tests (POCT) will become a cost-effective approach to advance diagnostic testing. CONCLUSION Despite conventional techniques are still being used in the field, the exploration and field implementation of advanced techniques for the diagnosis of malaria are still being developed rapidly.
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Affiliation(s)
- Loeki Enggar Fitri
- Department of Parasitology, Faculty of Medicine Universitas Brawijaya, Malang, Indonesia.,Malaria Research Group, Faculty of Medicine Universitas Brawijaya, Malang, Indonesia
| | - Tarina Widaningrum
- Malaria Research Group, Faculty of Medicine Universitas Brawijaya, Malang, Indonesia.,Department of Pharmacology, Faculty of Medicine Universitas Brawijaya, Malang, Indonesia
| | - Agustina Tri Endharti
- Department of Parasitology, Faculty of Medicine Universitas Brawijaya, Malang, Indonesia
| | - Muhammad Hatta Prabowo
- Department of Pharmacy, Faculty of Science Universitas Islam Indonesia, Sleman, Indonesia
| | - Nuning Winaris
- Department of Parasitology, Faculty of Medicine Universitas Brawijaya, Malang, Indonesia.,Malaria Research Group, Faculty of Medicine Universitas Brawijaya, Malang, Indonesia
| | - Rivo Yudhinata Brian Nugraha
- Department of Parasitology, Faculty of Medicine Universitas Brawijaya, Malang, Indonesia.,Malaria Research Group, Faculty of Medicine Universitas Brawijaya, Malang, Indonesia
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22
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Niyukuri D, Sinzinkayo D, Troth EV, Oduma CO, Barengayabo M, Ndereyimana M, Holzschuh A, Vera-Arias CA, Gebre Y, Badu K, Nyandwi J, Baza D, Juma E, Koepfli C. Performance of highly sensitive and conventional rapid diagnostic tests for clinical and subclinical Plasmodium falciparum infections, and hrp2/3 deletion status in Burundi. PLOS GLOBAL PUBLIC HEALTH 2022; 2:e0000828. [PMID: 36962426 PMCID: PMC10022336 DOI: 10.1371/journal.pgph.0000828] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/09/2022] [Accepted: 06/30/2022] [Indexed: 11/18/2022]
Abstract
Rapid diagnostic tests (RDTs) are a key tool for the diagnosis of malaria infections among clinical and subclinical individuals. Low-density infections, and deletions of the P. falciparum hrp2/3 genes (encoding the HRP2 and HRP3 proteins detected by many RDTs) present challenges for RDT-based diagnosis. The novel Rapigen Biocredit three-band Plasmodium falciparum HRP2/LDH RDT was evaluated among 444 clinical and 468 subclinical individuals in a high transmission setting in Burundi. Results were compared to the AccessBio CareStart HRP2 RDT, and qPCR with a sensitivity of <0.3 parasites/μL blood. Sensitivity compared to qPCR among clinical patients for the Biocredit RDT was 79.9% (250/313, either of HRP2/LDH positive), compared to 73.2% (229/313) for CareStart (P = 0.048). Specificity of the Biocredit was 82.4% compared to 96.2% for CareStart. Among subclinical infections, sensitivity was 72.3% (162/224) compared to 58.5% (131/224) for CareStart (P = 0.003), and reached 88.3% (53/60) in children <15 years. Specificity was 84.4% for the Biocredit and 93.4% for the CareStart RDT. No (0/362) hrp2 and 2/366 hrp3 deletions were observed. In conclusion, the novel RDT showed improved sensitivity for the diagnosis of P. falciparum.
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Affiliation(s)
- David Niyukuri
- Doctoral School, University of Burundi, Bujumbura, Burundi
- South African DSI-NRF Centre of Excellence in Epidemiological Modelling and Analysis, Stellenbosch University, Stellenbosch, South Africa
| | - Denis Sinzinkayo
- Doctoral School, University of Burundi, Bujumbura, Burundi
- National Malaria Control Program, Bujumbura, Burundi
| | - Emma V Troth
- Eck Institute for Global Health and Department of Biological Sciences, University of Notre Dame, Notre Dame, Indiana, United States of America
| | | | | | | | - Aurel Holzschuh
- Eck Institute for Global Health and Department of Biological Sciences, University of Notre Dame, Notre Dame, Indiana, United States of America
| | - Claudia A Vera-Arias
- Eck Institute for Global Health and Department of Biological Sciences, University of Notre Dame, Notre Dame, Indiana, United States of America
| | - Yilekal Gebre
- Eck Institute for Global Health and Department of Biological Sciences, University of Notre Dame, Notre Dame, Indiana, United States of America
| | - Kingsley Badu
- Kwame Nkrumah University of Science and Technology, Kumasi, Ghana
| | - Joseph Nyandwi
- Doctoral School, University of Burundi, Bujumbura, Burundi
- National Institute of Public Health, Bujumbura, Burundi
| | | | | | - Cristian Koepfli
- Eck Institute for Global Health and Department of Biological Sciences, University of Notre Dame, Notre Dame, Indiana, United States of America
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Iamrod K, Chaidee A, Rucksaken R, Kopolrat KY, Worasith C, Wongphutorn P, Intuyod K, Pinlaor S, Sithithaworn J, Sithithaworn P, Hongsrichan N. Development and Efficacy of Droplet Digital PCR for Detection of Strongyloides stercoralis in Stool. Am J Trop Med Hyg 2022; 106:312-319. [PMID: 34662861 PMCID: PMC8733496 DOI: 10.4269/ajtmh.21-0729] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2021] [Accepted: 09/01/2021] [Indexed: 01/03/2023] Open
Abstract
Human strongyloidiasis is one of the neglected tropical diseases caused by infection with soil-transmitted helminth Strongyloides stercoralis. Conventional stool examination, a method commonly used for diagnosis of S. stercoralis, has low sensitivity, especially in the case of light infections. Herein, we developed the droplet digital polymerase chain reaction (ddPCR) assay to detect S. stercoralis larvae in stool and compared its performance with real-time PCR and stool examination techniques (formalin ethyl-acetate concentration technique [FECT] and agar plate culture [APC]). The ddPCR results showed 98% sensitivity and 90% specificity, and real-time PCR showed 82% sensitivity and 76.7% specificity when compared with the microscopic methods. Moreover, ddPCR could detect a single S. stercoralis larva in feces, and cross-reactions with other parasites were not observed. In conclusion, a novel ddPCR method exhibited high sensitivity and specificity for detection of S. stercoralis in stool samples. This technique may help to improve diagnosis, particularly in cases with light infection. In addition, ddPCR technique might be useful for screening patients before starting immunosuppressive drug therapy, and follow-up after treatment of strongyloidiasis.
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Affiliation(s)
- Kantapong Iamrod
- Department of Parasitology, Faculty of Medicine, Khon Kaen University, Khon Kaen, Thailand
| | - Apisit Chaidee
- Department of Parasitology, Faculty of Medicine, Khon Kaen University, Khon Kaen, Thailand;,Cholangiocarcinoma Research Institute, Faculty of Medicine, Khon Kaen University, Khon Kaen, Thailand
| | - Rucksak Rucksaken
- Department of Veterinary Technology, Faculty of Veterinary Technology, Kasetsart University, Bangkok, Thailand
| | - Kulthida Y. Kopolrat
- Department of Parasitology, Faculty of Medicine, Khon Kaen University, Khon Kaen, Thailand;,Cholangiocarcinoma Research Institute, Faculty of Medicine, Khon Kaen University, Khon Kaen, Thailand
| | - Chanika Worasith
- Department of Parasitology, Faculty of Medicine, Khon Kaen University, Khon Kaen, Thailand;,Cholangiocarcinoma Research Institute, Faculty of Medicine, Khon Kaen University, Khon Kaen, Thailand
| | - Phattharaphon Wongphutorn
- Cholangiocarcinoma Research Institute, Faculty of Medicine, Khon Kaen University, Khon Kaen, Thailand;,Biomedical Science Program, Graduate School, Khonkaen University, Khon Kaen, Thailand
| | - Kitti Intuyod
- Cholangiocarcinoma Research Institute, Faculty of Medicine, Khon Kaen University, Khon Kaen, Thailand;,Department of Pathology, Faculty of Medicine, Khon Kaen University, Khon Kaen, Thailand
| | - Somchai Pinlaor
- Department of Parasitology, Faculty of Medicine, Khon Kaen University, Khon Kaen, Thailand;,Cholangiocarcinoma Research Institute, Faculty of Medicine, Khon Kaen University, Khon Kaen, Thailand
| | | | - Paiboon Sithithaworn
- Department of Parasitology, Faculty of Medicine, Khon Kaen University, Khon Kaen, Thailand;,Cholangiocarcinoma Research Institute, Faculty of Medicine, Khon Kaen University, Khon Kaen, Thailand
| | - Nuttanan Hongsrichan
- Department of Parasitology, Faculty of Medicine, Khon Kaen University, Khon Kaen, Thailand;,Cholangiocarcinoma Research Institute, Faculty of Medicine, Khon Kaen University, Khon Kaen, Thailand;,Address correspondence to Nuttanan Hongsrichan, Department of Parasitology, Faculty of Medicine, Khon Kaen University, Khon Kaen 40002, Thailand. E-mail:
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24
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Dahal P, Khanal B, Rai K, Kattel V, Yadav S, Bhattarai NR. Challenges in Laboratory Diagnosis of Malaria in a Low-Resource Country at Tertiary Care in Eastern Nepal: A Comparative Study of Conventional vs. Molecular Methodologies. J Trop Med 2021; 2021:3811318. [PMID: 34992661 PMCID: PMC8727160 DOI: 10.1155/2021/3811318] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2021] [Accepted: 12/13/2021] [Indexed: 11/17/2022] Open
Abstract
For ongoing malaria elimination programmes, available methods such as microscopy and rapid diagnostic tests (RDTs) cannot detect all malaria cases in acute febrile illness. These methods are entirely dependent on the course of infection, parasite load, and skilled technical resources. Our study objectives were to estimate the performance of light microscopy and a RDT as well as real-time PCR for the detection of the Plasmodium parasite. Altogether, 52 blood samples collected from patients with acute febrile illness were tested by microscopy, RDT, and real-time PCR. The results were compared in terms of sensitivity and specificity. Microscopy detected the malaria parasite in 5.8% of the blood samples whereas 13.5% were detected by the RDT and 27% by real-time PCR. Considering real-time PCR as the gold standard method, microscopy had a sensitivity of 21.4% and a specificity of 100%, and the RDT had a sensitivity of 28.6% and a specificity of 92.1%. Microscopy together with the RDT successfully detected malaria positive cases in blood samples of Ct value below 20, but both were unable to detect malaria cases between 26-40 Ct value ranges amplified by real-time PCR. Despite various diagnostic tools being available, microscopy still remains the method of choice for diagnosis, while the RDT is user-friendly when applied at the point of care. However, our preliminary results emphasize the need to implement the test with higher sensitivity and specificity in the context of a malaria elimination programme. Such programmes can be a crucial opportunity to understand the species prevalent in a low-endemic region. However, these results should be further verified with a large cohort study to document the submicroscopic infection.
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Affiliation(s)
- Pragyan Dahal
- Department of Microbiology, B. P. Koirala Institute of Health Sciences, Dharan, Nepal
| | - Basudha Khanal
- Department of Microbiology, B. P. Koirala Institute of Health Sciences, Dharan, Nepal
| | - Keshav Rai
- Department of Microbiology, B. P. Koirala Institute of Health Sciences, Dharan, Nepal
| | - Vivek Kattel
- Department of Internal Medicine, B. P. Koirala Institute of Health Sciences, Dharan, Nepal
| | - Satish Yadav
- Department of Pediatrics, B. P. Koirala Institute of Health Sciences, Dharan, Nepal
| | - Narayan Raj Bhattarai
- Department of Microbiology, B. P. Koirala Institute of Health Sciences, Dharan, Nepal
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25
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Review of the Current Landscape of the Potential of Nanotechnology for Future Malaria Diagnosis, Treatment, and Vaccination Strategies. Pharmaceutics 2021; 13:pharmaceutics13122189. [PMID: 34959470 PMCID: PMC8706932 DOI: 10.3390/pharmaceutics13122189] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2021] [Revised: 12/13/2021] [Accepted: 12/14/2021] [Indexed: 12/24/2022] Open
Abstract
Malaria eradication has for decades been on the global health agenda, but the causative agents of the disease, several species of the protist parasite Plasmodium, have evolved mechanisms to evade vaccine-induced immunity and to rapidly acquire resistance against all drugs entering clinical use. Because classical antimalarial approaches have consistently failed, new strategies must be explored. One of these is nanomedicine, the application of manipulation and fabrication technology in the range of molecular dimensions between 1 and 100 nm, to the development of new medical solutions. Here we review the current state of the art in malaria diagnosis, prevention, and therapy and how nanotechnology is already having an incipient impact in improving them. In the second half of this review, the next generation of antimalarial drugs currently in the clinical pipeline is presented, with a definition of these drugs' target product profiles and an assessment of the potential role of nanotechnology in their development. Opinions extracted from interviews with experts in the fields of nanomedicine, clinical malaria, and the economic landscape of the disease are included to offer a wider scope of the current requirements to win the fight against malaria and of how nanoscience can contribute to achieve them.
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26
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Hiillos A, Thonig A, Knott KE. Droplet digital PCR as a tool for investigating dynamics of cryptic symbionts. Ecol Evol 2021; 11:17381-17396. [PMID: 34938515 PMCID: PMC8668802 DOI: 10.1002/ece3.8372] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2021] [Revised: 10/28/2021] [Accepted: 10/29/2021] [Indexed: 12/11/2022] Open
Abstract
Interactions among symbiotic organisms and their hosts are major drivers of ecological and evolutionary processes. Monitoring the infection patterns among natural populations and identifying factors affecting these interactions are critical for understanding symbiont-host relationships. However, many of these interactions remain understudied since the knowledge about the symbiont species is lacking, which hinders the development of appropriate tools. In this study, we developed a digital droplet PCR (ddPCR) assay based on apicomplexan COX1 gene to detect an undescribed agamococcidian symbiont. We show that the method gives precise and reproducible results and enables detecting cryptic symbionts in low target concentration. We further exemplify the assay's use to survey seasonally sampled natural host (Pygospio elegans) populations for symbiont infection dynamics. We found that symbiont prevalence differs spatially but does not show seasonal changes. Infection load differed between populations and was low in spring and significantly increased towards fall in all populations. We also found that the symbiont prevalence is affected by host length and population density. Larger hosts were more likely to be infected, and high host densities were found to have a lower probability of infection. The observed variations could be due to characteristics of both symbiont and host biology, especially the seasonal variation in encounter rates. Our findings show that the developed ddPCR assay is a robust tool for detecting undescribed symbionts that are otherwise difficult to quantify, enabling further insight into the impact cryptic symbionts have on their hosts.
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Affiliation(s)
- Anna‐Lotta Hiillos
- Department of Biological and Environmental ScienceUniversity of JyväskyläJyväskyläFinland
| | - Anne Thonig
- Department of Biological and Environmental ScienceUniversity of JyväskyläJyväskyläFinland
- Department of Science and EnvironmentRoskilde UniversityRoskildeDenmark
| | - Karelyn Emily Knott
- Department of Biological and Environmental ScienceUniversity of JyväskyläJyväskyläFinland
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27
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Competitiveness of Quantitative Polymerase Chain Reaction (qPCR) and Droplet Digital Polymerase Chain Reaction (ddPCR) Technologies, with a Particular Focus on Detection of Antibiotic Resistance Genes (ARGs). Appl Microbiol 2021. [DOI: 10.3390/applmicrobiol1030028] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
With fast-growing polymerase chain reaction (PCR) technologies and various application methods, the technique has benefited science and medical fields. While having strengths and limitations on each technology, there are not many studies comparing the efficiency and specificity of PCR technologies. The objective of this review is to summarize a large amount of scattered information on PCR technologies focused on the two majorly used technologies: qPCR (quantitative polymerase chain reaction) and ddPCR (droplet-digital polymerase chain reaction). Here we analyze and compare the two methods for (1) efficiency, (2) range of detection and limitations under different disciplines and gene targets, (3) optimization, and (4) status on antibiotic resistance genes (ARGs) analysis. It has been identified that the range of detection and quantification limit varies depending on the PCR method and the type of sample. Careful optimization of target gene analysis is essential for building robust analysis for both qPCR and ddPCR. In our era where mutation of genes may lead to a pandemic of viral infectious disease or antibiotic resistance-induced health threats, this study hopes to set guidelines for meticulous detection, quantification, and analysis to help future prevention and protection of global health, the economy, and ecosystems.
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28
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Koepfli C, Nguitragool W, de Almeida ACG, Kuehn A, Waltmann A, Kattenberg E, Ome-Kaius M, Rarau P, Obadia T, Kazura J, Monteiro W, Darcy AW, Wini L, Bassat Q, Felger I, Sattabongkot J, Robinson LJ, Lacerda M, Mueller I. Identification of the asymptomatic Plasmodium falciparum and Plasmodium vivax gametocyte reservoir under different transmission intensities. PLoS Negl Trop Dis 2021; 15:e0009672. [PMID: 34449764 PMCID: PMC8428688 DOI: 10.1371/journal.pntd.0009672] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2020] [Revised: 09/09/2021] [Accepted: 07/21/2021] [Indexed: 11/25/2022] Open
Abstract
Background Understanding epidemiological variables affecting gametocyte carriage and density is essential to design interventions that most effectively reduce malaria human-to-mosquito transmission. Methodology/Principal findings Plasmodium falciparum and P. vivax parasites and gametocytes were quantified by qPCR and RT-qPCR assays using the same methodologies in 5 cross-sectional surveys involving 16,493 individuals in Brazil, Thailand, Papua New Guinea, and Solomon Islands. The proportion of infections with detectable gametocytes per survey ranged from 44–94% for P. falciparum and from 23–72% for P. vivax. Blood-stage parasite density was the most important predictor of the probability to detect gametocytes. In moderate transmission settings (prevalence by qPCR>5%), parasite density decreased with age and the majority of gametocyte carriers were children. In low transmission settings (prevalence<5%), >65% of gametocyte carriers were adults. Per survey, 37–100% of all individuals positive for gametocytes by RT-qPCR were positive by light microscopy for asexual stages or gametocytes (overall: P. falciparum 178/348, P. vivax 235/398). Conclusions/Significance Interventions to reduce human-to-mosquito malaria transmission in moderate-high endemicity settings will have the greatest impact when children are targeted. In contrast, all age groups need to be included in control activities in low endemicity settings to achieve elimination. Detection of infections by light microscopy is a valuable tool to identify asymptomatic blood stage infections that likely contribute most to ongoing transmission at the time of sampling. Plasmodium vivax and Plasmodium falciparum cause the vast majority of all human malaria cases. Across all transmission settings, a large proportion of infections of the two species remain asymptomatic. These infections are not diagnosed and treated by control programs focusing on clinical cases. They can carry gametocytes, the sexual stage of the parasite that establishes infections in mosquitos, thus asymptomatic infections contribute to transmission. In order to determine who is likely to contribute to transmission, gametocyte densities were measured by sensitive molecular methods in afebrile individuals in four countries. The proportion of infections with gametocytes varied greatly among surveys, and was higher in regions that had experienced low transmission for extended periods of time. In moderate-high transmission settings, gametocyte densities were particularly high in children below six years, highlighting the importance that interventions to reduce transmission include this age group. The majority of gametocyte carriers was positive by light microscopy. The comprehensive data on gametocyte carriage presented here lays the foundation for the development of more effective screen and treat activities to reduce malaria transmission.
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Affiliation(s)
- Cristian Koepfli
- Population Health & Immunity Division, Walter & Eliza Hall Institute, Parkville, Australia
- Department of Medical Biology, University of Melbourne, Parkville, Australia
- University of Notre Dame, Eck Institute for Global Health, Department of Biological Sciences, Notre Dame, Indiana, United States of America
- * E-mail:
| | - Wang Nguitragool
- Department of Molecular Tropical Medicine and Genetics, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Anne Cristine Gomes de Almeida
- Fundação de Medicina Tropical Dr. Heitor Vieira Dourado (FMT-HVD), Manaus, Brazil
- Universidade do Estado do Amazonas, Manaus, Brazil
| | - Andrea Kuehn
- ISGlobal, Hospital Clínic—Universitat de Barcelona, Barcelona, Spain
| | - Andreea Waltmann
- Population Health & Immunity Division, Walter & Eliza Hall Institute, Parkville, Australia
- Department of Medical Biology, University of Melbourne, Parkville, Australia
| | - Eline Kattenberg
- Population Health & Immunity Division, Walter & Eliza Hall Institute, Parkville, Australia
- Papua New Guinea Institute of Medical Research, Madang, Papua New Guinea
| | - Maria Ome-Kaius
- Population Health & Immunity Division, Walter & Eliza Hall Institute, Parkville, Australia
- Department of Medical Biology, University of Melbourne, Parkville, Australia
- Papua New Guinea Institute of Medical Research, Madang, Papua New Guinea
| | - Patricia Rarau
- Papua New Guinea Institute of Medical Research, Madang, Papua New Guinea
| | - Thomas Obadia
- Hub de Bioinformatique et Biostatistique, Département Biologie Computationnelle, Institut Pasteur, Paris, France
- Unité Malaria: parasites et Hôtes, Département Parasites et Insectes Vecteurs, Institut Pasteur, Paris, France
| | - James Kazura
- Centre for Global Health & Diseases, Case Western Reserve University, Cleveland, Ohio, United States of America
| | - Wuelton Monteiro
- Fundação de Medicina Tropical Dr. Heitor Vieira Dourado (FMT-HVD), Manaus, Brazil
- Universidade do Estado do Amazonas, Manaus, Brazil
| | - Andrew W. Darcy
- National Health Training and Research Institute, Ministry of Health, Honiara, Solomon Islands
| | - Lyndes Wini
- Vector Borne Diseases Program, Ministry of Health, Honiara, Solomon Islands
| | - Quique Bassat
- ISGlobal, Hospital Clínic—Universitat de Barcelona, Barcelona, Spain
- Centro de Investigação em Saúde de Manhiça (CISM), Maputo, Mozambique
- ICREA, Barcelona, Spain
- Pediatric Infectious Diseases Unit, Pediatrics Department, Hospital Sant Joan de Déu (University of Barcelona), Barcelona, Spain
- Consorcio de Investigación Biomédica en Red de Epidemiología y Salud Pública (CIBERESP), Madrid, Spain
| | - Ingrid Felger
- Swiss Tropical and Public Health Institute, Basel, Switzerland
| | - Jetsumon Sattabongkot
- Mahidol Vivax Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Leanne J. Robinson
- Population Health & Immunity Division, Walter & Eliza Hall Institute, Parkville, Australia
- Papua New Guinea Institute of Medical Research, Madang, Papua New Guinea
| | - Marcus Lacerda
- Fundação de Medicina Tropical Dr. Heitor Vieira Dourado (FMT-HVD), Manaus, Brazil
| | - Ivo Mueller
- Population Health & Immunity Division, Walter & Eliza Hall Institute, Parkville, Australia
- Department of Medical Biology, University of Melbourne, Parkville, Australia
- Unité Malaria: parasites et Hôtes, Département Parasites et Insectes Vecteurs, Institut Pasteur, Paris, France
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Assessment of Associations between Malaria Parasites and Avian Hosts-A Combination of Classic System and Modern Molecular Approach. BIOLOGY 2021; 10:biology10070636. [PMID: 34356491 PMCID: PMC8301060 DOI: 10.3390/biology10070636] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/06/2021] [Revised: 06/20/2021] [Accepted: 07/01/2021] [Indexed: 11/28/2022]
Abstract
Simple Summary Throughout history, frequent outbreaks of diseases in humans have occurred following transmission from animals. While some diseases can jump between birds and mammals, others are stuck to closely related species. Understanding the mechanisms of host–parasite associations will enable us to predict the outbreaks of diseases and will therefore be important to society and ecological health. For decades, scientists have attempted to reveal how host–parasite associations are formed and persist. The key is to assess the ability of the parasite to infect and reproduce within the host without killing the host. Related studies have faced numerous challenges, but technical advances are providing solutions and are gradually broadening our understanding. In this review, I use bird malaria and related blood parasites as a model system and summarize the important advances in techniques and perspectives and how they provide new approaches for understanding the evolution of host–parasite associations to further predict disease outbreaks. Abstract Avian malaria and related haemosporidian parasites are responsible for fitness loss and mortality in susceptible bird species. This group of globally distributed parasites has long been used as a classical system for investigating host–parasite associations. The association between a parasite and its hosts can be assessed by the prevalence in the host population and infection intensity in a host individual, which, respectively, reflect the ability of the parasite to infect the host and reproduce within the host. However, the latter has long been poorly investigated due to numerous challenges, such as lack of general molecular markers and limited sensitivity of traditional methods, especially when analysing naturally infected birds. The recent development of genetic databases, together with novel molecular methodologies, has shed light on this long-standing problem. Real-time quantitative PCR has enabled more accurate quantification of avian haemosporidian parasites, and digital droplet PCR further improved experimental sensitivity and repeatability of quantification. In recent decades, parallel studies have been carried out all over the world, providing great opportunities for exploring the adaptation of haemosporidian parasites to different hosts and the variations across time and space, and further investigating the coevolutionary history between parasites and their hosts. I hereby review the most important milestones in diagnosis techniques of avian haemosporidian parasites and illustrate how they provide new insights for understanding host–parasite associations.
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Towards a more healthy conservation paradigm: integrating disease and molecular ecology to aid biological conservation †. J Genet 2021. [PMID: 33622992 PMCID: PMC7371965 DOI: 10.1007/s12041-020-01225-7] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Parasites, and the diseases they cause, are important from an ecological and evolutionary perspective because they can negatively affect host fitness and can regulate host populations. Consequently, conservation biology has long recognized the vital role that parasites can play in the process of species endangerment and recovery. However, we are only beginning to understand how deeply parasites are embedded in ecological systems, and there is a growing recognition of the important ways in which parasites affect ecosystem structure and function. Thus, there is an urgent need to revisit how parasites are viewed from a conservation perspective and broaden the role that disease ecology plays in conservation-related research and outcomes. This review broadly focusses on the role that disease ecology can play in biological conservation. Our review specifically emphasizes on how the integration of tools and analytical approaches associated with both disease and molecular ecology can be leveraged to aid conservation biology. Our review first concentrates on disease-mediated extinctions and wildlife epidemics. We then focus on elucidating how host–parasite interactions has improved our understanding of the eco-evolutionary dynamics affecting hosts at the individual, population, community and ecosystem scales. We believe that the role of parasites as drivers and indicators of ecosystem health is especially an exciting area of research that has the potential to fundamentally alter our view of parasites and their role in biological conservation. The review concludes with a broad overview of the current and potential applications of modern genomic tools in disease ecology to aid biological conservation.
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Lei S, Chen S, Zhong Q. Digital PCR for accurate quantification of pathogens: Principles, applications, challenges and future prospects. Int J Biol Macromol 2021; 184:750-759. [PMID: 34171259 DOI: 10.1016/j.ijbiomac.2021.06.132] [Citation(s) in RCA: 28] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2021] [Revised: 06/16/2021] [Accepted: 06/18/2021] [Indexed: 12/25/2022]
Abstract
Pathogens pose a severe threat to food safety and human health. The traditional methods for pathogen detection can't meet the growing diagnosis and control need. Digital PCR (dPCR) attracts a considerable attention for its ability to absolutely quantify pathogens with features of high selectivity, simplicity, accuracy and rapidity. The dPCR technique that achieves absolute quantification based on end-point measurement without standard curve offers a guideline for further genetic analysis and molecular diagnosis. It could contribute to the quantification of low level of nucleic acid, early detection and timely prevention of pathogenic diseases. In this review, 1442 publications about dPCR were selected and the detections of various pathogens by dPCR were reviewed comprehensively, including viruses, bacteria, parasites and fungi. A number of examples are cited to illustrate that dPCR is a new powerful tool with desired accuracy, sensitivity, and reproducibility for quantification of different types of pathogens. Moreover, the benefits, challenges and future prospects of the dPCR were also highlighted in this review.
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Affiliation(s)
- Shuwen Lei
- Guangdong Provincial Key Laboratory of Food Quality and Safety, College of Food Science, South China Agricultural University, Guangzhou 510642, China; Guangdong Laboratory of Lingnan Modern Agriculture, South China Agricultural University, Guangzhou 510642, China
| | - Song Chen
- Guangdong Provincial Key Laboratory of Food Quality and Safety, College of Food Science, South China Agricultural University, Guangzhou 510642, China; Guangdong Laboratory of Lingnan Modern Agriculture, South China Agricultural University, Guangzhou 510642, China
| | - Qingping Zhong
- Guangdong Provincial Key Laboratory of Food Quality and Safety, College of Food Science, South China Agricultural University, Guangzhou 510642, China; Guangdong Laboratory of Lingnan Modern Agriculture, South China Agricultural University, Guangzhou 510642, China.
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Gimenez AM, Marques RF, Regiart M, Bargieri DY. Diagnostic Methods for Non-Falciparum Malaria. Front Cell Infect Microbiol 2021; 11:681063. [PMID: 34222049 PMCID: PMC8248680 DOI: 10.3389/fcimb.2021.681063] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2021] [Accepted: 05/31/2021] [Indexed: 11/13/2022] Open
Abstract
Malaria is a serious public health problem that affects mostly the poorest countries in the world, killing more than 400,000 people per year, mainly children under 5 years old. Among the control and prevention strategies, the differential diagnosis of the Plasmodium-infecting species is an important factor for selecting a treatment and, consequently, for preventing the spread of the disease. One of the main difficulties for the detection of a specific Plasmodium sp is that most of the existing methods for malaria diagnosis focus on detecting P. falciparum. Thus, in many cases, the diagnostic methods neglect the other non-falciparum species and underestimate their prevalence and severity. Traditional methods for diagnosing malaria may present low specificity or sensitivity to non-falciparum spp. Therefore, there is high demand for new alternative methods able to differentiate Plasmodium species in a faster, cheaper and easier manner to execute. This review details the classical procedures and new perspectives of diagnostic methods for malaria non-falciparum differential detection and the possibilities of their application in different circumstances.
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Affiliation(s)
- Alba Marina Gimenez
- Department of Parasitology, Institute of Biomedical Sciences, University of São Paulo, São Paulo, Brazil
| | - Rodolfo F. Marques
- Department of Clinical and Toxicological Analyses, School of Pharmaceutical Sciences, University of São Paulo, São Paulo, Brazil
| | - Matías Regiart
- Department of Fundamental Chemistry, Institute of Chemistry, University of São Paulo, São Paulo, Brazil
| | - Daniel Youssef Bargieri
- Department of Parasitology, Institute of Biomedical Sciences, University of São Paulo, São Paulo, Brazil
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Tarbiat B, Enweji N, Baltrusis P, Halvarsson P, Osterman-Lind E, Jansson DS, Höglund J. A novel duplex ddPCR assay for detection and differential diagnosis of Ascaridia galli and Heterakis gallinarum eggs from chickens feces. Vet Parasitol 2021; 296:109499. [PMID: 34144378 DOI: 10.1016/j.vetpar.2021.109499] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2021] [Revised: 06/06/2021] [Accepted: 06/07/2021] [Indexed: 11/30/2022]
Abstract
Since the EU ban on battery cages, many studies have listed Ascaridia galli and Heterakis gallinarum as the most common roundworms in the European laying hen population. A complicating factor is that the eggs of these parasites are almost identical. Thus, lack of molecular diagnostic approaches has driven epidemiological studies to take on necropsy for species discrimination, which is labor and cost intensive. Here, we describe a novel diagnostic tool based on droplet digital PCR for simultaneous identification and absolute quantification of the eggs of both of these ascarids in chickens' droppings using two different genus-specific primer-probe sets targeting the second internal transcribed spacer region (ITS-2) in the nuclear ribosomal (rRNA) gene array. No cross-reaction was observed when different combinations of DNA and species-specific primers and probes were tested. The lowest obtained frequency threshold for the detection of H. gallinarum in the presence of a constant A. galli DNA concentration was determined to be 0.8 %. After validation, we used the assay to analyze field samples collected from several Swedish laying hen farms. Out of 134 samples, 86 (64 %) were positive for A. galli while 11 (8.3 %) samples were positive for H. gallinarum. These samples were initially analyzed with flotation technique for detection of ascarid eggs. The results of the Cohen's kappa indicated substantial agreement (85.8 %) between the two tests. In conclusion, we have validated a novel molecular-based diagnostic tool for quantification and differentiation between intestinal parasites of major importance in chickens with high precision. Although this study focuses on identification of parasites of laying hens, the findings may well have a bearing on all types of chicken production systems. The present study lays the groundwork for future research into epidemiology of these two important chicken parasite species.
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Affiliation(s)
- B Tarbiat
- Department of Biomedical Sciences and Veterinary Public Health, Section for Parasitology, Swedish University of Agricultural Sciences (SLU), P.O. Box 7036, SE-750 07, Uppsala, Sweden.
| | - N Enweji
- Department of Biomedical Sciences and Veterinary Public Health, Section for Parasitology, Swedish University of Agricultural Sciences (SLU), P.O. Box 7036, SE-750 07, Uppsala, Sweden
| | - P Baltrusis
- Department of Biomedical Sciences and Veterinary Public Health, Section for Parasitology, Swedish University of Agricultural Sciences (SLU), P.O. Box 7036, SE-750 07, Uppsala, Sweden
| | - P Halvarsson
- Department of Biomedical Sciences and Veterinary Public Health, Section for Parasitology, Swedish University of Agricultural Sciences (SLU), P.O. Box 7036, SE-750 07, Uppsala, Sweden
| | - E Osterman-Lind
- Department of Microbiology, Section for Parasitological Diagnostics, National Veterinary Institute (SVA), SE-751 89, Uppsala, Sweden
| | - D S Jansson
- Department of Clinical Sciences, Swedish University of Agricultural Sciences (SLU), Box 7054, SE-750 07, Uppsala, Sweden; Department of Animal Health and Antimicrobial Strategies, National Veterinary Institute (SVA), SE751 89, Uppsala, Sweden
| | - J Höglund
- Department of Biomedical Sciences and Veterinary Public Health, Section for Parasitology, Swedish University of Agricultural Sciences (SLU), P.O. Box 7036, SE-750 07, Uppsala, Sweden
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Wang CYT, Ballard EL, Pava Z, Marquart L, Gaydon J, Murphy SC, Whiley D, O'Rourke P, McCarthy JS. Analytical validation of a real-time hydrolysis probe PCR assay for quantifying Plasmodium falciparum parasites in experimentally infected human adults. Malar J 2021; 20:181. [PMID: 33838672 PMCID: PMC8035755 DOI: 10.1186/s12936-021-03717-y] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2020] [Accepted: 03/29/2021] [Indexed: 11/10/2022] Open
Abstract
Background Volunteer infection studies have become a standard model for evaluating drug efficacy against Plasmodium infections. Molecular techniques such as qPCR are used in these studies due to their ability to provide robust and accurate estimates of parasitaemia at increased sensitivity compared to microscopy. The validity and reliability of assays need to be ensured when used to evaluate the efficacy of candidate drugs in clinical trials. Methods A previously described 18S rRNA gene qPCR assay for quantifying Plasmodium falciparum in blood samples was evaluated. Assay performance characteristics including analytical sensitivity, reportable range, precision, accuracy and specificity were assessed using experimental data and data compiled from phase 1 volunteer infection studies conducted between 2013 and 2019. Guidelines for validation of laboratory-developed molecular assays were followed. Results The reportable range was 1.50 to 6.50 log10 parasites/mL with a limit of detection of 2.045 log10 parasites/mL of whole blood based on a parasite diluted standard series over this range. The assay was highly reproducible with minimal intra-assay (SD = 0.456 quantification cycle (Cq) units [0.137 log10 parasites/mL] over 21 replicates) and inter-assay (SD = 0.604 Cq units [0.182 log10 parasites/mL] over 786 qPCR runs) variability. Through an external quality assurance program, the QIMR assay was shown to generate accurate results (quantitative bias + 0.019 log10 parasites/mL against nominal values). Specificity was 100% after assessing 164 parasite-free human blood samples. Conclusions The 18S rRNA gene qPCR assay is specific and highly reproducible and can provide reliable and accurate parasite quantification. The assay is considered fit for use in evaluating drug efficacy in malaria clinical trials. Supplementary Information The online version contains supplementary material available at 10.1186/s12936-021-03717-y.
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Affiliation(s)
- Claire Y T Wang
- Centre for Children's Health Research, Children's Health Queensland, Brisbane, Australia. .,Child Health Research Centre, The University of Queensland, Brisbane, Australia.
| | - Emma L Ballard
- QIMR Berghofer Medical Research Institute, Brisbane, Australia
| | - Zuleima Pava
- QIMR Berghofer Medical Research Institute, Brisbane, Australia
| | - Louise Marquart
- QIMR Berghofer Medical Research Institute, Brisbane, Australia
| | - Jane Gaydon
- Centre for Children's Health Research, Children's Health Queensland, Brisbane, Australia.,Child Health Research Centre, The University of Queensland, Brisbane, Australia
| | - Sean C Murphy
- Departments of Laboratory Medicine and Microbiology, University of Washington, Seattle, WA, USA.,Center for Emerging and Re-Emerging Infectious Diseases, University of Washington, Seattle, WA, USA
| | - David Whiley
- Centre for Children's Health Research, Children's Health Queensland, Brisbane, Australia.,UQ Centre for Clinical Research, Faculty of Medicine, The University of Queensland, Brisbane, Australia
| | - Peter O'Rourke
- QIMR Berghofer Medical Research Institute, Brisbane, Australia
| | - James S McCarthy
- QIMR Berghofer Medical Research Institute, Brisbane, Australia.,School of Medicine, The University of Queensland, Brisbane, Australia
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Srisutham S, Suwannasin K, Sugaram R, Dondorp AM, Imwong M. Measurement of gene amplifications related to drug resistance in Plasmodium falciparum using droplet digital PCR. Malar J 2021; 20:120. [PMID: 33639924 PMCID: PMC7916280 DOI: 10.1186/s12936-021-03659-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2020] [Accepted: 02/19/2021] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Copy number variations (CNVs) of the Plasmodium falciparum multidrug resistance 1 (pfmdr1), P. falciparum plasmepsin2 (pfplasmepsin2) and P. falciparum GTP cyclohydrolase 1 (pfgch1) genes are associated with anti-malarial drug resistance in P. falciparum malaria. Droplet digital PCR (ddPCR) assays have been developed for accurate assessment of CNVs in several human genes. The aim of the present study was to develop and validate ddPCR assays for detection of the CNVs of P. falciparum genes associated with resistance to anti-malarial drugs. METHODS A multiplex ddPCR assay was developed to detect the CNVs in the pfmdr1 and pfplasmepsin2 genes, while a duplex ddPCR assay was developed to detect CNV in the pfgch1 gene. The gene copy number (GCN) quantification limit, as well as the accuracy and precision of the ddPCR assays were determined and compared to conventional quantitative PCR (qPCR). In order to reduce the cost of testing, a multiplex ddPCR assay of two target genes, pfmdr1 and pfplasmepsin2, was validated. In addition, the CNVs of genes of field samples collected from Thailand from 2015 to 2019 (n = 84) were assessed by ddPCR and results were compared to qPCR as the reference assay. RESULTS There were no significant differences between the GCN results obtained from uniplex and multiplex ddPCR assays for detection of CNVs in the pfmdr1 and pfplasmepsin2 genes (p = 0.363 and 0.330, respectively). Based on the obtained gene copy number quantification limit, the accuracy and percent relative standard deviation (%RSD) value of the multiplex ddPCR assay were 95% and 5%, respectively, for detection of the CNV of the pfmdr1 gene, and 91% and 5% for detection of the CNV of the pfplasmepsin2 gene. There was no significant difference in gene copy numbers assessed by uniplex or duplex ddPCR assays regarding CNV in the pfgch1 gene (p = 0.276). The accuracy and %RSD value of the duplex ddPCR assay were 95% and 4%, respectively, regarding pfgch1 GCN. In the P. falciparum field samples, pfmdr1 and pfplasmepsin2 GCNs were amplified in 15% and 27% of samples from Ubon Ratchathani, Thailand, while pfgch1 GCN was amplified in 50% of samples from Yala, Thailand. There was 100% agreement between the GCN results obtained from the ddPCR and qPCR assays (κ = 1.00). The results suggested that multiplex ddPCR assay is the optional assay for the accurate detection of gene copy number without requiring calibration standards, while the cost and required time are reduced. Based on the results of this study, criteria for GCN detection by ddPCR analysis were generated. CONCLUSIONS The developed ddPCR assays are simple, accurate, precise and cost-effective tools for detection of the CNVs in the pfmdr1, pfplasmepsin2 and pfgch1 genes of P. falciparum. The ddPCR assay is a useful additional tool for the surveillance of anti-malarial drug resistance.
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Affiliation(s)
- Suttipat Srisutham
- Department of Clinical Microscopy, Faculty of Allied Health Sciences, Chulalongkorn University, Bangkok, Thailand
| | - Kanokon Suwannasin
- Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Rungniran Sugaram
- Division of Vector Borne Diseases, Department of Disease Control, Ministry of Public Health, Nonthaburi, Thailand
| | - Arjen M Dondorp
- Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, UK
| | - Mallika Imwong
- Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand.
- Department of Molecular Tropical Medicine and Genetics, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand.
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Oduma CO, Ogolla S, Atieli H, Ondigo BN, Lee MC, Githeko AK, Dent AE, Kazura JW, Yan G, Koepfli C. Increased investment in gametocytes in asymptomatic Plasmodium falciparum infections in the wet season. BMC Infect Dis 2021; 21:44. [PMID: 33422001 PMCID: PMC7797145 DOI: 10.1186/s12879-020-05761-6] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2020] [Accepted: 12/30/2020] [Indexed: 11/10/2022] Open
Abstract
Background Transmission stemming from asymptomatic infections is increasingly being recognized as a threat to malaria elimination. In many regions, malaria transmission is seasonal. It is not well understood whether Plasmodium falciparum modulates its investment in transmission to coincide with seasonal vector abundance. Methods We sampled 1116 asymptomatic individuals in the wet season, when vectors are abundant, and 1743 in the dry season, in two sites in western Kenya, representing different transmission intensities (Chulaimbo, moderate transmission, and Homa Bay, low transmission). Blood samples were screened for P. falciparum by qPCR, and gametocytes by pfs25 RT-qPCR. Results Parasite prevalence by qPCR was 27.1% (Chulaimbo, dry), 48.2% (Chulaimbo, wet), 9.4% (Homabay, dry), and 7.8% (Homabay, wet). Mean parasite densities did not differ between seasons (P = 0.562). pfs25 transcripts were detected in 119/456 (26.1%) of infections. In the wet season, fewer infections harbored detectable gametocytes (22.3% vs. 33.8%, P = 0.009), but densities were 3-fold higher (wet: 3.46 transcripts/uL, dry: 1.05 transcripts/uL, P < 0.001). In the dry season, 4.0% of infections carried gametocytes at moderate-to-high densities likely infective (> 1 gametocyte per 2 uL blood), compared to 7.9% in the wet season. Children aged 5–15 years harbored 76.7% of infections with gametocytes at moderate-to-high densities. Conclusions Parasites increase their investment in transmission in the wet season, reflected by higher gametocyte densities. Despite increased gametocyte densities, parasite density remained similar across seasons and were often below the limit of detection of microscopy or rapid diagnostic test, thus a large proportion of infective infections would escape population screening in the wet season. Seasonal changes of gametocytemia in asymptomatic infections need to be considered when designing malaria control measures. Supplementary Information The online version contains supplementary material available at 10.1186/s12879-020-05761-6.
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Affiliation(s)
- Colins O Oduma
- Department of Biochemistry and Molecular Biology, Egerton University, P. O Box 536, Nakuru, 20115, Kenya.,Kenya Medical Research Institute/Centre for Global Health Research, P. O Box 1578, Kisumu, 40100, Kenya
| | - Sidney Ogolla
- Kenya Medical Research Institute/Centre for Global Health Research, P. O Box 1578, Kisumu, 40100, Kenya
| | - Harrysone Atieli
- School of Public Health, Maseno University, P. O Box 3275, Maseno, 40100, Kenya.,International Center of Excellence for Malaria Research, P. O Box 199, Homa Bay, 40300, Kenya
| | - Bartholomew N Ondigo
- Department of Biochemistry and Molecular Biology, Egerton University, P. O Box 536, Nakuru, 20115, Kenya.,Laboratory of Malaria Immunology and Vaccinology, National Institute of Allergy and Infectious Diseases, National Institute Health, Bethesda, MD, 20892, USA
| | - Ming-Chieh Lee
- Program in Public Health, College of Health Sciences, University of California, Irvine, CA, 92697, USA
| | - Andrew K Githeko
- International Center of Excellence for Malaria Research, P. O Box 199, Homa Bay, 40300, Kenya
| | - Arlene E Dent
- Case Western Reserve University, Center for Global Health and Diseases, LC 4983, Cleveland, OH, 44106, USA
| | - James W Kazura
- Case Western Reserve University, Center for Global Health and Diseases, LC 4983, Cleveland, OH, 44106, USA
| | - Guiyun Yan
- Program in Public Health, College of Health Sciences, University of California, Irvine, CA, 92697, USA
| | - Cristian Koepfli
- Eck Institute for Global Health and Department of Biological Sciences, University of Notre Dame, Notre Dame, IN, 46556-0369, USA.
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Modernizing the Toolkit for Arthropod Bloodmeal Identification. INSECTS 2021; 12:insects12010037. [PMID: 33418885 PMCID: PMC7825046 DOI: 10.3390/insects12010037] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/08/2020] [Revised: 12/30/2020] [Accepted: 12/31/2020] [Indexed: 11/24/2022]
Abstract
Simple Summary The ability to identify the source of vertebrate blood in mosquitoes, ticks, and other blood-feeding arthropod vectors greatly enhances our knowledge of how vector-borne pathogens are spread. The source of the bloodmeal is identified by analyzing the remnants of blood remaining in the arthropod at the time of capture, though this is often fraught with challenges. This review provides a roadmap and guide for those considering modern techniques for arthropod bloodmeal identification with a focus on progress made in the field over the past decade. We highlight genome regions that can be used to identify the vertebrate source of arthropod bloodmeals as well as technological advances made in other fields that have introduced innovative new ways to identify vertebrate meal source based on unique properties of the DNA sequence, protein signatures, or residual molecules present in the blood. Additionally, engineering progress in miniaturization has led to a number of field-deployable technologies that bring the laboratory directly to the arthropods at the site of collection. Although many of these advancements have helped to address the technical challenges of the past, the challenge of successfully analyzing degraded DNA in bloodmeals remains to be solved. Abstract Understanding vertebrate–vector interactions is vitally important for understanding the transmission dynamics of arthropod-vectored pathogens and depends on the ability to accurately identify the vertebrate source of blood-engorged arthropods in field collections using molecular methods. A decade ago, molecular techniques being applied to arthropod blood meal identification were thoroughly reviewed, but there have been significant advancements in the techniques and technologies available since that time. This review highlights the available diagnostic markers in mitochondrial and nuclear DNA and discusses their benefits and shortcomings for use in molecular identification assays. Advances in real-time PCR, high resolution melting analysis, digital PCR, next generation sequencing, microsphere assays, mass spectrometry, and stable isotope analysis each offer novel approaches and advantages to bloodmeal analysis that have gained traction in the field. New, field-forward technologies and platforms have also come into use that offer promising solutions for point-of-care and remote field deployment for rapid bloodmeal source identification. Some of the lessons learned over the last decade, particularly in the fields of DNA barcoding and sequence analysis, are discussed. Though many advancements have been made, technical challenges remain concerning the prevention of sample degradation both by the arthropod before the sample has been obtained and during storage. This review provides a roadmap and guide for those considering modern techniques for arthropod bloodmeal identification and reviews how advances in molecular technology over the past decade have been applied in this unique biomedical context.
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Lei S, Gu X, Zhong Q, Duan L, Zhou A. Absolute quantification of Vibrio parahaemolyticus by multiplex droplet digital PCR for simultaneous detection of tlh, tdh and ureR based on single intact cell. Food Control 2020. [DOI: 10.1016/j.foodcont.2020.107207] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
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Huang X, Huang D, Liang Y, Zhang L, Yang G, Liu B, Peng Y, Deng W, Dong L. A new protocol for absolute quantification of haemosporidian parasites in raptors and comparison with current assays. Parasit Vectors 2020; 13:354. [PMID: 32680557 PMCID: PMC7368712 DOI: 10.1186/s13071-020-04195-y] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2020] [Accepted: 06/17/2020] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Accurate quantification of infection intensity is essential to estimate infection patterns of avian haemosporidian parasites in order to understand the evolution of host-parasite associations. Traditional microscopy is cost-effective but requires high-quality blood smears and considerable experience, while the widely used semi-quantitative qPCR methods are mostly employed with ideal, laboratory-based golden samples and standard curves, which may limit the comparison of parasitemia from different laboratories. METHODS Here we present a digital droplet PCR (ddPCR) protocol for absolute quantification of avian haemosporidians in raptors. Novel primers were designed that target a conserved fragment of a rRNA region of the mitochondrial genome of the parasites. Sensitivity and repeatability were evaluated compared to qPCR and other assays. RESULTS This ddPCR assay enables accurate quantification of haemosporidian parasites belonging to Plasmodium, Haemoproteus and Leucocytozoon with minimum infection quantities of 10-5 (i.e. one parasite copy in 105 host genomes) without the use of standard curves. Quantities assessed by ddPCR were more accurate than qPCR using the same primers through reduction of non-specific amplification in low-intensity samples. The ddPCR technique was more consistent among technical duplicates and reactions, especially when infection intensities were low, and this technique demonstrated equal sensitivity with high correspondence (R2 = 0.97) compared to the widely used qPCR assay. Both ddPCR and qPCR identified more positive samples than the standard nested PCR protocol for the cytb gene used for barcoding avian haemosporidians. CONCLUSIONS We developed a novel ddPCR assay enabling accurate quantification of avian haemosporidians without golden samples or standard curves. This assay can be used as a robust method for investigating infection patterns in different host-parasite assemblages and can facilitate the comparison of results from different laboratories.
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Affiliation(s)
- Xi Huang
- College of Life Sciences, Beijing Normal University, Beijing, China.,MOE Key Laboratory for Biodiversity Sciences and Ecological Engineering, Beijing Normal University, Beijing, China
| | - Di Huang
- College of Life Sciences, Beijing Normal University, Beijing, China
| | - Yuge Liang
- College of Life Sciences, Beijing Normal University, Beijing, China
| | - Linlin Zhang
- College of Life Sciences, Beijing Normal University, Beijing, China
| | - Guocheng Yang
- College of Life Sciences, Beijing Normal University, Beijing, China
| | - Boye Liu
- Shaanxi Institute of Zoology, Xi'an, China
| | - Yangyang Peng
- College of Life Sciences, Beijing Normal University, Beijing, China
| | - Wenhong Deng
- College of Life Sciences, Beijing Normal University, Beijing, China. .,MOE Key Laboratory for Biodiversity Sciences and Ecological Engineering, Beijing Normal University, Beijing, China.
| | - Lu Dong
- College of Life Sciences, Beijing Normal University, Beijing, China. .,MOE Key Laboratory for Biodiversity Sciences and Ecological Engineering, Beijing Normal University, Beijing, China.
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Mahendran P, Liew JWK, Amir A, Ching XT, Lau YL. Droplet digital polymerase chain reaction (ddPCR) for the detection of Plasmodium knowlesi and Plasmodium vivax. Malar J 2020; 19:241. [PMID: 32650774 PMCID: PMC7350699 DOI: 10.1186/s12936-020-03314-5] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2019] [Accepted: 07/04/2020] [Indexed: 12/15/2022] Open
Abstract
BACKGROUND Plasmodium knowlesi and Plasmodium vivax are the predominant Plasmodium species that cause malaria in Malaysia and play a role in asymptomatic malaria disease transmission in Malaysia. The diagnostic tools available to diagnose malaria, such as microscopy and rapid diagnostic test (RDT), are less sensitive at detecting lower parasite density. Droplet digital polymerase chain reaction (ddPCR), which has been shown to have higher sensitivity at diagnosing malaria, allows direct quantification without the need for a standard curve. The aim of this study is to develop and use a duplex ddPCR assay for the detection of P. knowlesi and P. vivax, and compare this method to nested PCR and qPCR. METHODS The concordance rate, sensitivity and specificity of the duplex ddPCR assay were determined and compared to nested PCR and duplex qPCR. RESULTS The duplex ddPCR assay had higher analytical sensitivity (P. vivax = 10 copies/µL and P. knowlesi = 0.01 copies/µL) compared to qPCR (P. vivax = 100 copies/µL and P. knowlesi = 10 copies/µL). Moreover, the ddPCR assay had acceptable clinical sensitivity (P. vivax = 80% and P. knowlesi = 90%) and clinical specificity (P. vivax = 87.84% and P. knowlesi = 81.08%) when compared to nested PCR. Both ddPCR and qPCR detected more double infections in the samples. CONCLUSIONS Overall, the ddPCR assay demonstrated acceptable efficiency in detection of P. knowlesi and P. vivax, and was more sensitive than nested PCR in detecting mixed infections. However, the duplex ddPCR assay still needs optimization to improve the assay's clinical sensitivity and specificity.
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Affiliation(s)
- Punitha Mahendran
- Department of Biomedical Science, Faculty of Medicine, University of Malaya, 50603, Kuala Lumpur, Malaysia
| | - Jonathan Wee Kent Liew
- Department of Parasitology, Faculty of Medicine, University of Malaya, 50603, Kuala Lumpur, Malaysia
| | - Amirah Amir
- Department of Parasitology, Faculty of Medicine, University of Malaya, 50603, Kuala Lumpur, Malaysia
| | - Xiao-Teng Ching
- Canvio Sdn. Bhd, Setia Alam, 40170, Shah Alam, Selangor, Malaysia
| | - Yee-Ling Lau
- Department of Parasitology, Faculty of Medicine, University of Malaya, 50603, Kuala Lumpur, Malaysia.
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Pomari E, Silva R, Moro L, La Marca G, Perandin F, Verra F, Bisoffi Z, Piubelli C. Droplet Digital PCR for the Detection of Plasmodium falciparum DNA in Whole Blood and Serum: A Comparative Analysis with Other Molecular Methods. Pathogens 2020; 9:pathogens9060478. [PMID: 32560386 PMCID: PMC7350319 DOI: 10.3390/pathogens9060478] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2020] [Revised: 06/08/2020] [Accepted: 06/15/2020] [Indexed: 12/24/2022] Open
Abstract
Background: The estimation of Plasmodium falciparum parasitaemia can vary according to the method used. Recently, droplet digital PCR (ddPCR) has been proposed as a promising approach in the molecular quantitation of Plasmodium, but its ability to predict the actual parasitaemia on clinical samples has not been largely investigated. Moreover, the possibility of applying the ddPCR-sensitive method to serum samples has never been explored. Methods: We used, for the first time, ddPCR on both blood and serum to detect the DNA of P. falciparum in 52 paired samples from 26 patients. ddPCR was compared with loop-mediated isothermal amplification (LAMP) and rtPCR. The correlation between the ddPCR results, microscopy, and clinical parameters was examined. Results: ddPCR and microscopy were found to be strongly correlated (ρ(26) = 0.83111, p < 0.0001) in blood. Samples deviating from the correlation were partially explained by clinical parameters. In serum samples, ddPCR revealed the best performance in detecting P. falciparum DNA, with 77% positive samples among malaria subjects. Conclusion: Absolute quantitation by ddPCR can be a flexible technique for Plasmodium detection, with potential application in the diagnosis of malaria. In particular, ddPCR is a powerful approach for Plasmodium DNA analysis on serum when blood samples are unavailable.
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Affiliation(s)
- Elena Pomari
- Department of Infectious, Tropical Diseases and Microbiology, IRCCS Sacro Cuore Don Calabria Hospital, Negrar di Valpolicella, 37024 Verona, Italy; (R.S.); (L.M.); (G.L.M.); (F.P.); (F.V.); (Z.B.)
- Correspondence: (E.P.); (C.P.)
| | - Ronaldo Silva
- Department of Infectious, Tropical Diseases and Microbiology, IRCCS Sacro Cuore Don Calabria Hospital, Negrar di Valpolicella, 37024 Verona, Italy; (R.S.); (L.M.); (G.L.M.); (F.P.); (F.V.); (Z.B.)
| | - Lucia Moro
- Department of Infectious, Tropical Diseases and Microbiology, IRCCS Sacro Cuore Don Calabria Hospital, Negrar di Valpolicella, 37024 Verona, Italy; (R.S.); (L.M.); (G.L.M.); (F.P.); (F.V.); (Z.B.)
| | - Giulia La Marca
- Department of Infectious, Tropical Diseases and Microbiology, IRCCS Sacro Cuore Don Calabria Hospital, Negrar di Valpolicella, 37024 Verona, Italy; (R.S.); (L.M.); (G.L.M.); (F.P.); (F.V.); (Z.B.)
| | - Francesca Perandin
- Department of Infectious, Tropical Diseases and Microbiology, IRCCS Sacro Cuore Don Calabria Hospital, Negrar di Valpolicella, 37024 Verona, Italy; (R.S.); (L.M.); (G.L.M.); (F.P.); (F.V.); (Z.B.)
| | - Federica Verra
- Department of Infectious, Tropical Diseases and Microbiology, IRCCS Sacro Cuore Don Calabria Hospital, Negrar di Valpolicella, 37024 Verona, Italy; (R.S.); (L.M.); (G.L.M.); (F.P.); (F.V.); (Z.B.)
| | - Zeno Bisoffi
- Department of Infectious, Tropical Diseases and Microbiology, IRCCS Sacro Cuore Don Calabria Hospital, Negrar di Valpolicella, 37024 Verona, Italy; (R.S.); (L.M.); (G.L.M.); (F.P.); (F.V.); (Z.B.)
- Department of Diagnostics and Public Health, University of Verona, 37134 Verona, Italy
| | - Chiara Piubelli
- Department of Infectious, Tropical Diseases and Microbiology, IRCCS Sacro Cuore Don Calabria Hospital, Negrar di Valpolicella, 37024 Verona, Italy; (R.S.); (L.M.); (G.L.M.); (F.P.); (F.V.); (Z.B.)
- Correspondence: (E.P.); (C.P.)
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Maganira JD, Kidima W, Mwita CJ, Halvarsson P, Höglund J. Soil contamination by Taenia solium egg DNA in rural villages in Kongwa district, Tanzania. Infect Ecol Epidemiol 2020; 10:1772668. [PMID: 32922689 PMCID: PMC7448889 DOI: 10.1080/20008686.2020.1772668] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
The presence ofTaenia solium DNA from eggs in soils around the households in four Tanzanian villages in Kongwa district were analysed in relation to seasonal fluctuations and infection risk implications. A total of 192 pooled soil samples from five sampling points per household were examined by droplet digital Polymerase Chain Reaction (ddPCR) from 96 pig-keeping households both during the dry and rainy seasons. The pooled samples were first processed by a flotation-double sieving technique, followed by screening for worm DNA employing universal primers targeting the mitochondrial cytochrome c oxidase subunit I (cox1) gene of human taeniid species and some other helminths. All DNA positive samples were later confirmed by a specific ddPCR probe assay targeting the mitochondrial cox1 gene of T. solium. A total of 17.2% (n = 33) samples were positive with the universal ddPCR, whereas T. solium DNA was confirmed by the specific ddPCR only in 3.1% (n = 3) of the surveyed households. The detection of T. solium DNA in this study spells out a low risk of exposure to T. solium eggs from contaminated household soil. Based on our results, ddPCR seems to be a promising technology for screening T. solium eggs in soil.
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Affiliation(s)
- Justine Daudi Maganira
- Department of Biosciences, Sokoine University of Agriculture, Morogoro, Tanzania.,Department of Biomedical Sciences and Veterinary Public Health, Swedish University of Agricultural Sciences, Uppsala, Sweden
| | - Winifrida Kidima
- Department of Zoology and Wildlife Conservation, University of Dar Es Salaam, Dar Es Salaam, Tanzania
| | - Chacha John Mwita
- Department of Aquatic Sciences and Fisheries Technology, University of Dar Es Salaam, Dar Es Salaam, Tanzania
| | - Peter Halvarsson
- Department of Biomedical Sciences and Veterinary Public Health, Swedish University of Agricultural Sciences, Uppsala, Sweden
| | - Johan Höglund
- Department of Biomedical Sciences and Veterinary Public Health, Swedish University of Agricultural Sciences, Uppsala, Sweden
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43
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Ristaino JB, Saville AC, Paul R, Cooper DC, Wei Q. Detection of Phytophthora infestans by Loop-Mediated Isothermal Amplification, Real-Time LAMP, and Droplet Digital PCR. PLANT DISEASE 2020; 104:708-716. [PMID: 31967506 DOI: 10.1094/pdis-06-19-1186-re] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Phytophthora infestans is the causal agent of potato late blight, a devastating disease of tomato and potato and a threat to global food security. Early detection and intervention is essential for effective management of the pathogen. We developed a loop-mediated isothermal amplification (LAMP) assay for P. infestans and compared this assay to conventional PCR, real-time LAMP, and droplet digital PCR for detection of P. infestans. The LAMP assay was specific for P. infestans on potato and tomato and did not amplify other potato- or tomato-infecting Phytophthora species or other fungal and bacterial pathogens that infect potato and tomato. The detection threshold for SYBR Green LAMP and real-time LAMP read with hydroxynaphthol blue and EvaGreen was 1 pg/µl. In contrast, detection by conventional PCR was 10 pg/µl. Droplet digital PCR had the lowest detection threshold (100 fg/µl). We adapted the LAMP assay using SYBR Green and a mobile reader (mReader) for use in the field. Detection limits were 584 fg/µl for SYBR Green LAMP read on the mReader, which was more sensitive than visualization with the human eye. The mobile platform records geospatial coordinates and data from positive pathogen detections can be directly uploaded to a cloud database. Data can then be integrated into disease surveillance networks. This system will be useful for real-time detection of P. infestans and will improve the timeliness of reports into surveillance systems such as USABlight or EuroBlight.
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Affiliation(s)
- Jean B Ristaino
- Department of Entomology and Plant Pathology, North Carolina State University, Raleigh, NC 27695
- Emerging Plant Disease and Global Food Security Cluster, North Carolina State University, Raleigh, NC 27695
| | - Amanda C Saville
- Department of Entomology and Plant Pathology, North Carolina State University, Raleigh, NC 27695
| | - Rajesh Paul
- Department of Chemical and Biomolecular Engineering, North Carolina State University, Raleigh, NC 27695
| | | | - Qingshan Wei
- Emerging Plant Disease and Global Food Security Cluster, North Carolina State University, Raleigh, NC 27695
- Department of Chemical and Biomolecular Engineering, North Carolina State University, Raleigh, NC 27695
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44
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Peng Z, Wu T. High-throughput Droplet Array Generated by Roller Nanoimprint Lithography with Biomimetic Surfaces. ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. ANNUAL INTERNATIONAL CONFERENCE 2020; 2019:1074-1077. [PMID: 31946080 DOI: 10.1109/embc.2019.8857579] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
For the first time, we exploited a novel pump-free and high-throughput droplet generation method using the roller nanoimprint technology on biomimetic peristome surface of nepenthes. The biomimetic nepenthes peristome surfaces with oblique re-entrant microcavities and sharp edges led to facile directional liquid filling and high-efficiency droplet generation under the roller embossing, and the sealant on polyethylene terephthalate (PET) substrate encapsulated thousands of microcavities to form a high-density droplet array with good uniformity.
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45
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Salipante SJ, Jerome KR. Digital PCR—An Emerging Technology with Broad Applications in Microbiology. Clin Chem 2019; 66:117-123. [DOI: 10.1373/clinchem.2019.304048] [Citation(s) in RCA: 54] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2019] [Accepted: 09/18/2019] [Indexed: 01/10/2023]
Abstract
Abstract
BACKGROUND
The PCR and its variant, quantitative PCR (qPCR), have revolutionized the practice of clinical microbiology. Continued advancements in PCR have led to a new derivative, digital PCR (dPCR), which promises to address certain limitations inherent to qPCR.
CONTENT
Here we highlight the important technical differences between qPCR and dPCR, and the potential advantages and disadvantages of each. We then review specific situations in which dPCR has been implemented in clinical microbiology and the results of such applications. Finally, we attempt to place dPCR in the context of other emerging technologies relevant to the clinical laboratory, including next-generation sequencing.
SUMMARY
dPCR offers certain clear advantages over traditional qPCR, but these are to some degree offset by limitations of the technology, at least as currently practiced. Laboratories considering implementation of dPCR should carefully weigh the potential advantages and disadvantages of this powerful technique for each specific application planned.
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Affiliation(s)
| | - Keith R Jerome
- Department of Laboratory Medicine, University of Washington, Seattle, WA
- Vaccine and Infectious Disease Division, Fred Hutchinson Cancer Research Center, Seattle, WA
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46
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Gitta B, Kilian N. Diagnosis of Malaria Parasites Plasmodium spp. in Endemic Areas: Current Strategies for an Ancient Disease. Bioessays 2019; 42:e1900138. [PMID: 31830324 DOI: 10.1002/bies.201900138] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2019] [Revised: 11/05/2019] [Indexed: 12/14/2022]
Abstract
Fast and effective detection of the causative agent of malaria in humans, protozoan Plasmodium parasites, is of crucial importance for increasing the effectiveness of treatment and to control a devastating disease that affects millions of people living in endemic areas. The microscopic examination of Giemsa-stained blood films still remains the gold-standard in Plasmodium detection today. However, there is a high demand for alternative diagnostic methods that are simple, fast, highly sensitive, ideally do not rely on blood-drawing and can potentially be conducted by the patients themselves. Here, the history of Plasmodium detection is discussed, and advantages and disadvantages of diagnostic methods that are currently being applied are assessed.
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Affiliation(s)
- Brian Gitta
- Matibabu, 120 Semawata Rd, Ntinda, Kampala, 00256, Uganda
| | - Nicole Kilian
- Centre for Infectious Diseases, Parasitology Heidelberg University Hospital, Im Neuenheimer Feld 324, 69120, Heidelberg, Germany
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47
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Validation of droplet digital Polymerase Chain Reaction for the detection and absolute quantification of Taenia solium eggs in spiked soil samples. Acta Trop 2019; 200:105175. [PMID: 31526776 DOI: 10.1016/j.actatropica.2019.105175] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2019] [Revised: 09/12/2019] [Accepted: 09/13/2019] [Indexed: 02/07/2023]
Abstract
To enable the detection of taeniid eggs in environmental samples, a sensitive technology is required. In this study, we validated the effectiveness of a digital droplet Polymerase Chain Reaction (ddPCR) assay for detection, identification and absolute quantification of taeniid DNA from artificially contaminated soils with varying numbers of taeniid eggs using a set of universal primers, JB3 & JB4.5. The results showed that the number of cox1 copies detected increased gradually for both species with the number of taeniid eggs added to the different soil types. The highest cox1 DNA copies recovery for Taenia solium and T. lynciscapreoli was from the sand soil with lowest recovery being observed in clay soils. Therefore, ddPCR is a promising technology for screening of taeniid eggs from soil samples collected in the environment irrespective of the soil type and the number of eggs. The potential of the ddPCR protocol to detect taeniid egg DNA in spiked soil samples has great practical application for taeniid egg screening in soils from endemic areas. However, when universal primers are used in screening environmental samples, the identity of ddPCR positive samples must be confirmed by sequencing. In addition, more validation studies using species-specific primers and field soil samples is recommended.
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48
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Ballard E, Wang CYT, Hien TT, Tong NT, Marquart L, Pava Z, Tarning J, O'Rourke P, McCarthy JS. A validation study of microscopy versus quantitative PCR for measuring Plasmodium falciparum parasitemia. Trop Med Health 2019; 47:49. [PMID: 31485189 PMCID: PMC6712708 DOI: 10.1186/s41182-019-0176-3] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2019] [Accepted: 08/12/2019] [Indexed: 12/02/2022] Open
Abstract
Microscopy and 18S qPCR are the most common and field-friendly methods for quantifying malaria parasite density, and it is important that these methods can be interpreted as giving equivalent results. We compared results of quantitative measurement of Plasmodium falciparum parasitemia by microscopy and by 18S qPCR in a phase 2a study. Microscopy positive samples (n = 355; median 810 parasites/μL [IQR 40–10,471]) showed close agreement with 18S qPCR in mean log10/mL transformed parasitemia values by paired t test (difference 0.04, 95%CI − 0.01–0.10, p = 0.088). Excellent intraclass correlation (0.97) and no evidence of systematic or proportional differences by Passing–Bablok regression were observed. 18S qPCR appears to give equivalent parasitemia values to microscopy, which indicates 18S qPCR is an appropriate alternative method to quantify parasitemia in clinical trials.
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Affiliation(s)
- Emma Ballard
- 1QIMR Berghofer Medical Research Institute, Brisbane, Australia
| | - Claire Y T Wang
- Queensland Paediatric Infectious Diseases Laboratory, Centre for Children's Health Research, Brisbane, Australia
| | - Tran Tinh Hien
- 3Oxford University Clinical Research Unit-Hospital for Tropical Diseases, Ho Chi Minh City, Vietnam
| | - Nguyen Thanh Tong
- 3Oxford University Clinical Research Unit-Hospital for Tropical Diseases, Ho Chi Minh City, Vietnam
| | - Louise Marquart
- 1QIMR Berghofer Medical Research Institute, Brisbane, Australia
| | - Zuleima Pava
- 1QIMR Berghofer Medical Research Institute, Brisbane, Australia
| | - Joel Tarning
- 4Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand.,5Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, Oxford University, Oxford, UK
| | - Peter O'Rourke
- 1QIMR Berghofer Medical Research Institute, Brisbane, Australia
| | - James S McCarthy
- 1QIMR Berghofer Medical Research Institute, Brisbane, Australia.,6The University of Queensland, Brisbane, Australia
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49
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Development of a film-based immunochromatographic microfluidic device for malaria diagnosis. Biomed Microdevices 2019; 21:86. [PMID: 31451957 DOI: 10.1007/s10544-019-0431-8] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
In this study, a novel film-based immunochromatographic microfluidic device (IMD) has been developed for malaria diagnosis. A microfluidic channel was patterned on a polyethylene terephthalate (PET) double-sided adhesive film using a plotting cutter and was assembled with a polycarbonate (PC) film. The PC film used for the probe immobilization layer was activated using oxygen plasma treatment to modify the film surface with avidin-biotin linker to immobilize a capture antibody. A fluorescent labeled Pan type mAb conjugate was prepared for signal indicator after undergoing a sandwich enzyme-linked immunosorbent assay (ELISA). Target antigens include Plasmodium falciparum (P. falciparum) lactate dehydrogenase (LDH) and Plasmodium vivax (P. vivax) LDH which were injected into the sample inlet. Target antigens combined with the conjugate and then flowed to the detection chamber where two test dots and a control dot (Ctrl) exist. In the presence of P. falciparum LDH, three detection dots including test dot 1 (T1), test dot 2 (T2) and Ctrl revealed fluorescence signals where P. falciparum mAb, Pan type pLDH mAb and goat anti-mouse IgG were immobilized, respectively. When P. vivax LDH was present, T2 and Ctrl dots showed fluorescence signals while no signal was detected with the negative control. P. falciparum LDH and P. vivax LDH were successfully detected on the IMD with a detection limit of 50 ng/mL and 100 ng/mL, respectively. The IMD provides a point-of-care diagnosis platform which is able to analyze pathogenic bacteria and viruses that can be applied in the field of clinical diagnosis and food safety testing.
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50
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Lin Y, Ye J, Luo M, Hu B, Wu D, Wen J, Yang C, Li Y, Ning Y. Group B Streptococcus DNA Copy Numbers Measured by Digital PCR Correlates with Perinatal Outcomes. Anal Chem 2019; 91:9466-9471. [PMID: 31269399 DOI: 10.1021/acs.analchem.8b05872] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Group B Streptococcus (GBS) is a one of the main causes of perinatal disease, yet the method for GBS detection, broth-enriched culture, is time-consuming and has low sensitivity and accuracy. We aimed to develop a GBS digital PCR (GBS-dPCR) assay for detecting GBS colonization. More rapid and accurate detection of GBS colonization could increase GBS diagnosis and treatment closer to delivery. A single-center, retrospective, case-controlled study was performed. A total of 182 rectovaginal swabs from pregnant women, who were undergoing prenatal screening by broth-enriched culture, were evaluated using GBS-dPCR targeting the cfb gene of GBS. Pregnant women with GBS colonization were followed up for correlation analysis between GBS DNA copy numbers and perinatal outcomes. The results of the GBS-dPCR assay were compared to those from the broth-enriched culture, which is the gold standard for GBS detection. The sensitivity and specificity of GBS-dPCR were 98% and 92.5%, respectively. By discrepant result analysis, the specificity of GBS-dPCR was raised to 97.4%. The incidence of premature rupture of membrane (PROM) and neonatal infection were statistically significantly positively correlated with GBS DNA copy numbers. GBS-dPCR has the advantage of directly detecting GBS colonization from swabs with high specificity and sensitivity, while reducing turnaround time (<4 h). Analysis of clinical samples with GBS-dPCR shows that GBS DNA copy numbers are positively correlated with the incidence of PROM and neonatal infection, suggesting that dPCR is a promising method for detection of GBS colonization during pregnancy.
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Affiliation(s)
- Yanqing Lin
- School of Laboratory Medicine and Biotechnology , Southern Medical University , Guangzhou 510515 , People's Republic of China.,Affiliated Shenzhen Maternity & Healthcare Hospital , Southern Medical University , Shenzhen 518028 , People's Republic of China
| | - Jianbin Ye
- School of Laboratory Medicine and Biotechnology , Southern Medical University , Guangzhou 510515 , People's Republic of China.,Zhuhai SMU Biomedicine Public Service Platform LLC , Zhuhai 519040 , People's Republic of China
| | - Meiqun Luo
- School of Laboratory Medicine and Biotechnology , Southern Medical University , Guangzhou 510515 , People's Republic of China
| | - Bingxin Hu
- School of Laboratory Medicine and Biotechnology , Southern Medical University , Guangzhou 510515 , People's Republic of China
| | - Danlin Wu
- School of Laboratory Medicine and Biotechnology , Southern Medical University , Guangzhou 510515 , People's Republic of China
| | - Junjie Wen
- School of Laboratory Medicine and Biotechnology , Southern Medical University , Guangzhou 510515 , People's Republic of China
| | - Chuanzhong Yang
- Affiliated Shenzhen Maternity & Healthcare Hospital , Southern Medical University , Shenzhen 518028 , People's Republic of China
| | - Yan Li
- School of Laboratory Medicine and Biotechnology , Southern Medical University , Guangzhou 510515 , People's Republic of China
| | - Yunshan Ning
- School of Laboratory Medicine and Biotechnology , Southern Medical University , Guangzhou 510515 , People's Republic of China
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