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La Porta E, Baiardi P, Fassina L, Faragli A, Perna S, Tovagliari F, Tallone I, Talamo G, Secondo G, Mazzarello G, Esposito V, Pasini M, Lupo F, Deferrari G, Bassetti M, Esposito C. The role of kidney dysfunction in COVID-19 and the influence of age. Sci Rep 2022; 12:8650. [PMID: 35606394 PMCID: PMC9125966 DOI: 10.1038/s41598-022-12652-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2021] [Accepted: 05/06/2022] [Indexed: 12/15/2022] Open
Abstract
COVID-19 is strongly influenced by age and comorbidities. Acute kidney injury (AKI) is a frequent finding in COVID-19 patients and seems to be associated to mortality and severity. On the other hand, the role of kidney dysfunction in COVID-19 is still debated. We performed a retrospective study in a cohort of 174 hospitalized COVID-19 patients in Italy from March 3rd to May 21st 2020, to investigate the role of kidney dysfunction on COVID-19 severity and mortality. Moreover, we examined in depth the relationship between kidney function, age, and progression of COVID-19, also using different equations to estimate the glomerular filtration rate (GFR). We performed logistic regressions, while a predictive analysis was made through a machine learning approach. AKI and death occurred respectively in 10.2% and 19.5%, in our population. The major risk factors for mortality in our cohort were age [adjusted HR, 6.2; 95% confidence interval (CI) 1.8-21.4] and AKI [3.36 (1.44-7.87)], while, in these relationships, GFR at baseline mitigated the role of age. The occurrence of AKI was influenced by baseline kidney function, D-dimer, procalcitonin and hypertension. Our predictive analysis for AKI and mortality reached an accuracy of ≥ 94% and ≥ 91%, respectively. Our study scales down the role of kidney function impairment on hospital admission , especially in elderly patients. BIS-1 formula demonstrated a worse performance to predict the outcomes in COVID-19 patients when compared with MDRD and CKD-EPI.
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Affiliation(s)
- Edoardo La Porta
- Division of Nephrology, Dialysis and Transplantation, Scientific Institute for Research and Health Care, IRCCS Istituto Giannina Gaslini, via Gerolamo Gaslini 5, 16147, Genoa, Italy.
- Department of Internal Medicine (DiMi), University of Genoa, Genoa, Italy.
| | - Paola Baiardi
- Scientific Direction, Istituti Clinici Scientifici Maugeri IRCCS, Pavia, Italy
| | - Lorenzo Fassina
- Department of Electrical, Computer and Biomedical Engineering, University of Pavia, Pavia, Italy
| | - Alessandro Faragli
- Department of Cardiology, Charité-University Medicine Berlin, Campus Virchow Klinikum, Berlin, Germany
| | - Simone Perna
- Department of Biology, Sakhir Campus, College of Science, University of Bahrain, Sakhir, Bahrain
| | | | - Ilaria Tallone
- Nephrology Department, Ospedale San Paolo, Savona, Italy
| | | | | | - Giovanni Mazzarello
- Infectious Disease Clinic Genoa University, Ospedale San Martino, Genoa, Italy
| | - Vittoria Esposito
- Nephrology and Dialysis Unit, Istituti Clinici Scientifici Maugeri IRCCS, Pavia, Italy
| | - Matteo Pasini
- Department of Cardionephrology, Istituto Clinico Ligure Di Alta Specialità (ICLAS), GVM Care and Research, Rapallo, GE, Italy
| | - Francesca Lupo
- Department of Cardionephrology, Istituto Clinico Ligure Di Alta Specialità (ICLAS), GVM Care and Research, Rapallo, GE, Italy
| | - Giacomo Deferrari
- Department of Internal Medicine (DiMi), University of Genoa, Genoa, Italy
- Department of Cardionephrology, Istituto Clinico Ligure Di Alta Specialità (ICLAS), GVM Care and Research, Rapallo, GE, Italy
| | - Matteo Bassetti
- Infectious Disease Clinic Genoa University, Ospedale San Martino, Genoa, Italy
| | - Ciro Esposito
- Nephrology and Dialysis Unit, Istituti Clinici Scientifici Maugeri IRCCS, Pavia, Italy
- University of Pavia, Pavia, Italy
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Animut A, Lindtjørn B. Use of epidemiological and entomological tools in the control and elimination of malaria in Ethiopia. Malar J 2018; 17:26. [PMID: 29329545 PMCID: PMC5767068 DOI: 10.1186/s12936-018-2172-1] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2017] [Accepted: 01/08/2018] [Indexed: 11/13/2022] Open
Abstract
Malaria is the leading public health problem in Ethiopia where over 75% of the land surface is at risk with varying intensities depending on altitude and season. Although the mortality because of malaria infection has declined much during the last 15–20 years, some researchers worry that this success story may not be sustainable. Past notable achievements in the reduction of malaria disease burden could be reversed in the future. To interrupt, or even to eliminate malaria transmission in Ethiopia, there is a need to implement a wide range of interventions that include insecticide-treated bed nets, indoor residual spraying, improved control of residual malaria transmission, and improved diagnostics, enhanced surveillance, and methods to deal with the emergence of resistance both to drugs and to insecticides. Developments during the past years with increasing awareness about the role of very low levels of malaria prevalence can sustain infections, may also demand that tools not used in the routine control efforts to reduce or eliminate malaria, should now be made available in places where malaria transmission occurs.
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Affiliation(s)
- Abebe Animut
- Aklilu Lemma Institute of Pathobiology, Addis Ababa University, P. O. Box 1176, Addis Ababa, Ethiopia.
| | - Bernt Lindtjørn
- Center for International Health, University of Bergen, Bergen, Norway
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Abstract
Basic science holds enormous power for revealing the biological mechanisms of disease and, in turn, paving the way toward new, effective interventions. Recognizing this power, the 2011 Research Agenda for Malaria Eradication included key priorities in fundamental research that, if attained, could help accelerate progress toward disease elimination and eradication. The Malaria Eradication Research Agenda (malERA) Consultative Panel on Basic Science and Enabling Technologies reviewed the progress, continuing challenges, and major opportunities for future research. The recommendations come from a literature of published and unpublished materials and the deliberations of the malERA Refresh Consultative Panel. These areas span multiple aspects of the Plasmodium life cycle in both the human host and the Anopheles vector and include critical, unanswered questions about parasite transmission, human infection in the liver, asexual-stage biology, and malaria persistence. We believe an integrated approach encompassing human immunology, parasitology, and entomology, and harnessing new and emerging biomedical technologies offers the best path toward addressing these questions and, ultimately, lowering the worldwide burden of malaria.
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Fu C, Lopes S, Mellor S, Aryal S, Sovannaroth S, Roca-Feltrer A. Experiences From Developing and Upgrading a Web-Based Surveillance System for Malaria Elimination in Cambodia. JMIR Public Health Surveill 2017; 3:e30. [PMID: 28615155 PMCID: PMC5489705 DOI: 10.2196/publichealth.6942] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2016] [Revised: 03/01/2017] [Accepted: 03/29/2017] [Indexed: 11/18/2022] Open
Abstract
Strengthening the surveillance component is key toward achieving country-wide malaria elimination in Cambodia. A Web-based upgraded malaria information system (MIS) was deemed to essentially act as the central component for surveillance strengthening. New functionality (eg, data visualization) and operational (eg, data quality) attributes of the system received particular attention. However, building from the lessons learned in previous systems’ developments, other aspects unique to Cambodia were considered to be equally important; for instance, feasibility issues, particularly at the field level (eg, user acceptability at various health levels), and sustainability needs (eg, long-term system flexibility). The Cambodian process of identifying the essential changes and critical attributes for this new information system can provide a model for other countries at various stages of the disease control and elimination continuum. Sharing these experiences not only facilitates the establishment of “best practices” but also accelerates global and regional malaria elimination efforts. In this article, Cambodia’s experience in developing and upgrading its MIS to remain responsive to country-specific needs demonstrates the necessity for considering functionality, operationalization, feasibility, and sustainability of an information system in the context of malaria elimination.
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Affiliation(s)
| | | | | | - Siddhi Aryal
- Malaria Consortium Asia Regional OfficeBangkokThailand
| | - Siv Sovannaroth
- The National Center for Parasitology, Entomology and Malaria ControlPhnom PenhCambodia
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5
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López-Gutiérrez B, Dinglasan RR, Izquierdo L. Sugar nucleotide quantification by liquid chromatography tandem mass spectrometry reveals a distinct profile in Plasmodium falciparum sexual stage parasites. Biochem J 2017; 474:897-905. [PMID: 28104756 PMCID: PMC5340172 DOI: 10.1042/bcj20161030] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2016] [Revised: 01/12/2017] [Accepted: 01/18/2017] [Indexed: 11/17/2022]
Abstract
The obligate intracellular lifestyle of Plasmodium falciparum and the difficulties in obtaining sufficient amounts of biological material have hampered the study of specific metabolic pathways in the malaria parasite. Thus, for example, the pools of sugar nucleotides required to fuel glycosylation reactions have never been studied in-depth in well-synchronized asexual parasites or in other stages of its life cycle. These metabolites are of critical importance, especially considering the renewed interest in the presence of N-, O-, and other glycans in key parasite proteins. In this work, we adapted a liquid chromatography tandem mass spectrometry (LC-MS/MS) method based on the use of porous graphitic carbon (PGC) columns and MS-friendly solvents to quantify sugar nucleotides in the malaria parasite. We report the thorough quantification of the pools of these metabolites throughout the intraerythrocytic cycle of P. falciparum The sensitivity of the method enabled, for the first time, the targeted analysis of these glycosylation precursors in gametocytes, the parasite sexual stages that are transmissible to the mosquito vector.
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Affiliation(s)
- Borja López-Gutiérrez
- ISGlobal, Barcelona Ctr. Int. Health Res. (CRESIB), Hospital Clínic - Universitat de Barcelona, Barcelona, Spain
| | - Rhoel R Dinglasan
- Department of Infectious Diseases & Pathology, The University of Florida Emerging Pathogens Institute, Gainesville, FL 32611, U.S.A
| | - Luis Izquierdo
- ISGlobal, Barcelona Ctr. Int. Health Res. (CRESIB), Hospital Clínic - Universitat de Barcelona, Barcelona, Spain
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Population genetics structure of Plasmodium vivax circumsporozoite protein during the elimination process in low and unstable malaria transmission areas, southeast of Iran. Acta Trop 2016; 160:23-34. [PMID: 27102931 DOI: 10.1016/j.actatropica.2016.04.006] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2015] [Revised: 04/14/2016] [Accepted: 04/15/2016] [Indexed: 11/20/2022]
Abstract
In Iran, the prevalence of Plasmodium falciparum and Plasmodium vivax has dropped after a national malaria elimination program was launched. To estimate the likelihood of success and to measure the outcome of malaria intervention tools during elimination programs (2008-2012), the population genetic surveys of Iranian P. vivax isolates (n=60) were carried out using the CSP genetic marker. The results were compared with a similar work that was carried out during a control phase (2000-2003) in the same study areas. Based on PCR-RFLP analysis, 49 (81.67%) of 60 studied samples were VK210 and 11 (18.33%) were VK247 with no mixed genotypes. However, 10.97% of P. vivax isolates of control phase harbored the mixed genotypes. Sequencing analysis of 50 pvcsp gene showed 14 distinct haplotypes, of which 11 and 3 were VK210 and VK247 types, respectively. However, during the control phase, 19 distinct subtypes (11 VK210 and 8 VK247) were reported. Also, 7 of 11 VK210 and the VK247F subtypes were new, and 3 out of 7 new VK210 and VK247F were isolated from the patients with Pakistani nationality. The lower nucleotide diversity per site (π=0.02017±0.00436 and π=0.04525±0.00255) and haplotype diversity (Hd=0.513±0.093 and Hd=0.691±0.128) as well as lower In/Del haplotype [Hd(i)=0.243 and 0] and nucleotide diversity [π(i)=0.00078 and 0] were recorded for VK210 and VK247of the elimination samples, respectively. In conclusion, the comparison of PRMs and RATs in CRR along with the polymorphism analysis of the sequence lengths, SNPs, and In/Del polymorphisms in all analyzed samples showed lower genetic diversity for PvCSP in the elimination samples. Also, although there is a turnover of P. vivax parasite genotypes in the study areas, reduction in genetic diversity and transmission was detected due to scaling-up of the intervention tools during an elimination program in Iran. This notable challenge of the elimination program must be taken into account and controlled by active surveillance for limiting both reintroductions of new allelic forms as well as the spread of drug-resistant parasite to prevent any disease outbreaks.
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Chen JH, Chen SB, Wang Y, Ju C, Zhang T, Xu B, Shen HM, Mo XJ, Molina DM, Eng M, Liang X, Gardner MJ, Wang R, Hu W. An immunomics approach for the analysis of natural antibody responses to Plasmodium vivax infection. MOLECULAR BIOSYSTEMS 2016; 11:2354-63. [PMID: 26091354 DOI: 10.1039/c5mb00330j] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
High throughput immunomics is a powerful platform to discover potential targets of host immunity and develop diagnostic tests for infectious diseases. We screened the sera of Plasmodium vivax-exposed individuals to profile the antibody response to blood-stage antigens of P. vivax using a P. vivax protein microarray. A total of 1936 genes encoding the P. vivax proteins were expressed, printed and screened with sera from P. vivax-exposed individuals and normal subjects. Total of 151 (7.8% of the 1936 targets) highly immunoreactive antigens were identified, including five well-characterized antigens of P. vivax (ETRAMP11.2, Pv34, SUB1, RAP2 and MSP4). Among the highly immunoreactive antigens, 5 antigens were predicted as adhesins by MAAP, and 11 antigens were predicted as merozoite invasion-related proteins based on homology with P. falciparum proteins. There are 40 proteins that have serodiagnostic potential for antibody surveillance. These novel Plasmodium antigens identified provide the clues for understanding host immune response to P. vivax infection and the development of antibody surveillance tools.
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Affiliation(s)
- Jun-Hu Chen
- National Institute of Parasitic Diseases, Chinese Center for Disease Control and Prevention, Key Laboratory of Parasite and Vector Biology of the Chinese Ministry of Health, WHO Collaborating Center for Malaria, Schistosomiasis and Filariasis, Shanghai 200025, People's Republic of China.
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Valzano M, Cecarini V, Cappelli A, Capone A, Bozic J, Cuccioloni M, Epis S, Petrelli D, Angeletti M, Eleuteri AM, Favia G, Ricci I. A yeast strain associated to Anopheles mosquitoes produces a toxin able to kill malaria parasites. Malar J 2016; 15:21. [PMID: 26754943 PMCID: PMC4709964 DOI: 10.1186/s12936-015-1059-7] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2015] [Accepted: 12/17/2015] [Indexed: 11/18/2022] Open
Abstract
Background Malaria control strategies are focusing on new approaches, such as the symbiotic control, which consists in the use of microbial symbionts to prevent parasite development in the mosquito gut and to block the transmission of the infection to humans. Several microbes, bacteria and fungi, have been proposed for malaria or other mosquito-borne diseases control strategies. Among these, the yeast Wickerhamomyces anomalus has been recently isolated from the gut of Anopheles mosquitoes, where it releases a natural antimicrobial toxin. Interestingly, many environmental strains of W. anomalus exert a wide anti-bacterial/fungal activity and some of these ‘killer’ yeasts are already used in industrial applications as food and feed bio-preservation agents. Since a few studies showed that W. anomalus killer strains have antimicrobial effects also against protozoan parasites, the possible anti-plasmodial activity of the yeast was investigated. Methods A yeast killer toxin (KT), purified through combined chromatographic techniques from a W. anomalus strain isolated from the malaria vector Anopheles stephensi, was tested as an effector molecule to target the sporogonic stages of the rodent malaria parasite Plasmodium berghei, in vitro. Giemsa staining was used to detect morphological damages in zygotes/ookinetes after treatment with the KT. Furthermore, the possible mechanism of action of the KT was investigated pre-incubating the protein with castanospermine, an inhibitor of β-glucanase activity. Results A strong anti-plasmodial effect was observed when the P. berghei sporogonic stages were treated with KT, obtaining an inhibition percentage up to around 90 %. Microscopy analysis revealed several ookinete alterations at morphological and structural level, suggesting the direct implication of the KT-enzymatic activity. Moreover, evidences of the reduction of KT activity upon treatment with castanospermine propose a β-glucanase-mediated activity. Conclusion The results showed the in vitro killing efficacy of a protein produced by a mosquito strain of W. anomalus against malaria parasites. Further studies are required to test the KT activity against the sporogonic stages in vivo, nevertheless this work opens new perspectives for the possible use of killer strains in innovative strategies to impede the development of the malaria parasite in mosquito vectors by the means of microbial symbionts. Electronic supplementary material The online version of this article (doi:10.1186/s12936-015-1059-7) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Matteo Valzano
- School of Biosciences and Veterinary Medicine, University of Camerino, 62032, Camerino, Italy.
| | - Valentina Cecarini
- School of Biosciences and Veterinary Medicine, University of Camerino, 62032, Camerino, Italy.
| | - Alessia Cappelli
- School of Biosciences and Veterinary Medicine, University of Camerino, 62032, Camerino, Italy.
| | - Aida Capone
- School of Biosciences and Veterinary Medicine, University of Camerino, 62032, Camerino, Italy.
| | - Jovana Bozic
- School of Biosciences and Veterinary Medicine, University of Camerino, 62032, Camerino, Italy.
| | - Massimiliano Cuccioloni
- School of Biosciences and Veterinary Medicine, University of Camerino, 62032, Camerino, Italy.
| | - Sara Epis
- Department of Veterinary Sciences and Public Health, University of Milan, 20133, Milan, Italy.
| | - Dezemona Petrelli
- School of Biosciences and Veterinary Medicine, University of Camerino, 62032, Camerino, Italy.
| | - Mauro Angeletti
- School of Biosciences and Veterinary Medicine, University of Camerino, 62032, Camerino, Italy.
| | - Anna Maria Eleuteri
- School of Biosciences and Veterinary Medicine, University of Camerino, 62032, Camerino, Italy.
| | - Guido Favia
- School of Biosciences and Veterinary Medicine, University of Camerino, 62032, Camerino, Italy.
| | - Irene Ricci
- School of Biosciences and Veterinary Medicine, University of Camerino, 62032, Camerino, Italy.
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Salinas JL, Kissinger JC, Jones DP, Galinski MR. Metabolomics in the fight against malaria. Mem Inst Oswaldo Cruz 2015; 109:589-97. [PMID: 25185001 PMCID: PMC4156452 DOI: 10.1590/0074-0276140043] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2014] [Accepted: 03/11/2014] [Indexed: 02/06/2023] Open
Abstract
Metabolomics uses high-resolution mass spectrometry to provide a chemical fingerprint of thousands of metabolites present in cells, tissues or body fluids. Such metabolic phenotyping has been successfully used to study various biologic processes and disease states. High-resolution metabolomics can shed new light on the intricacies of host-parasite interactions in each stage of the Plasmodium life cycle and the downstream ramifications on the host's metabolism, pathogenesis and disease. Such data can become integrated with other large datasets generated using top-down systems biology approaches and be utilised by computational biologists to develop and enhance models of malaria pathogenesis relevant for identifying new drug targets or intervention strategies. Here, we focus on the promise of metabolomics to complement systems biology approaches in the quest for novel interventions in the fight against malaria. We introduce the Malaria Host-Pathogen Interaction Center (MaHPIC), a new systems biology research coalition. A primary goal of the MaHPIC is to generate systems biology datasets relating to human and non-human primate (NHP) malaria parasites and their hosts making these openly available from an online relational database. Metabolomic data from NHP infections and clinical malaria infections from around the world will comprise a unique global resource.
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Affiliation(s)
- Jorge L Salinas
- Division of Infectious Diseases, Emory University School of Medicine, Emory University, Atlanta, GA, USA
| | - Jessica C Kissinger
- Department of Genetics, Institute of Bioinformatics, Center for Tropical and Emerging Global Diseases, University of Georgia, Athens, GA, USA
| | - Dean P Jones
- Division of Pulmonary Medicine, Department of Medicine, Emory University School of Medicine, Emory University, Atlanta, GA, USA
| | - Mary R Galinski
- Division of Infectious Diseases, Emory University School of Medicine, Emory University, Atlanta, GA, USA
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Val FF, Sampaio VS, Cassera MB, Andrade RT, Tauil PL, Monteiro WM, Lacerda MVG. Plasmodium vivax malaria elimination: should innovative ideas from the past be revisited? Mem Inst Oswaldo Cruz 2015; 109:522-4. [PMID: 25184997 PMCID: PMC4156444 DOI: 10.1590/0074-0276140240] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2014] [Accepted: 07/25/2014] [Indexed: 01/13/2023] Open
Abstract
In the 1950s, the strategy of adding chloroquine to food salt as a prophylaxis
against malaria was considered to be a successful tool. However, with the development
of Plasmodium resistance in the Brazilian Amazon, this control
strategy was abandoned. More than 50 years later, asexual stage resistance can be
avoided by screening for antimalarial drugs that have a selective action against
gametocytes, thus old prophylactic measures can be revisited. The efficacy of the old
methods should be tested as complementary tools for the elimination of malaria.
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Affiliation(s)
| | | | - Maria Belén Cassera
- Department of Biochemistry, Virginia Tech Center for Drug Discovery, Virginia Tech, Blacksburg, VA, USA
| | | | - Pedro Luiz Tauil
- Faculdade de Medicina, Universidade de Brasília, Brasília, DF, Brasil
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11
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Silal SP, Little F, Barnes KI, White LJ. Predicting the impact of border control on malaria transmission: a simulated focal screen and treat campaign. Malar J 2015; 14:268. [PMID: 26164675 PMCID: PMC4499227 DOI: 10.1186/s12936-015-0776-2] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2014] [Accepted: 06/28/2015] [Indexed: 12/31/2022] Open
Abstract
Background South Africa is one of many countries committed to malaria elimination with a target of 2018 and all malaria-endemic provinces, including Mpumalanga, are increasing efforts towards this ambitious goal. The reduction of imported infections is a vital element of an elimination strategy, particularly if a country is already experiencing high levels of imported infections. Border control of malaria is one tool that may be considered. Methods A metapopulation, non-linear stochastic ordinary differential equation model is used to simulate malaria transmission in Mpumalanga and Maputo province, Mozambique (the source of the majority of imported infections) to predict the impact of a focal screen and treat campaign at the Mpumalanga–Maputo border. This campaign is simulated by nesting an individual-based model for the focal screen and treat campaign within the metapopulation transmission model. Results The model predicts that such a campaign, simulated for different levels of resources, coverage and take-up rates with a variety of screening tools, will not eliminate malaria on its own, but will reduce transmission substantially. Making the campaign mandatory decreases transmission further though sub-patent infections are likely to remain undetected if the diagnostic tool is not adequately sensitive. Replacing screening and treating with mass drug administration results in substantially larger decreases as all (including sub-patent) infections are treated before movement into Mpumalanga. Conclusions The reduction of imported cases will be vital to any future malaria control or elimination strategy. This simulation predicts that FSAT at the Mpumalanga–Maputo border will be unable to eliminate local malaria on its own, but may still play a key role in detecting and treating imported infections before they enter the country. Thus FSAT may form part of an integrated elimination strategy where a variety of interventions are employed together to achieve malaria elimination. Electronic supplementary material The online version of this article (doi:10.1186/s12936-015-0776-2) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Sheetal P Silal
- Department of Statistical Sciences, University of Cape Town, Rondebosch, Cape Town, 7700, South Africa.
| | - Francesca Little
- Department of Statistical Sciences, University of Cape Town, Rondebosch, Cape Town, 7700, South Africa.
| | - Karen I Barnes
- Division of Clinical Pharmacology, Department of Medicine, University of Cape Town, Observatory, Cape Town, 7925, South Africa.
| | - Lisa J White
- Mahidol-Oxford Tropical Medicine Research Unit, Mahidol University, Bangkok, Thailand. .,Nuffield Department of Clinical Medicine, Centre for Tropical Medicine, Churchill Hospital, University of Oxford, Oxford, UK.
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12
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Prieto JH, Fischer E, Koncarevic S, Yates J, Becker K. Large-scale differential proteome analysis in Plasmodium falciparum under drug treatment. Methods Mol Biol 2014; 1201:269-79. [PMID: 25388121 DOI: 10.1007/978-1-4939-1438-8_17] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/21/2023]
Abstract
Here, we establish a methodology for large-scale quantitative proteomics using SIL (stable isotope labeling) to examine protein expression changes in trophozoite stages of the malaria parasite Plasmodium falciparum following drug treatment. For this purpose, exposure to (13)C6 (15)N1-isoleucine was optimized in order to obtain 99% atomic enrichment. Proteome fractionation with anion exchange chromatography was used to reduce sample complexity and increase quantitative coverage of protein expression. Tryptic peptides of subfractions were subjected to SCX/RP separation, measured by LC-MS/MS, and quantified using the software tool Census. In drug-treated parasites, we identified a total number of 1,253 proteins, thus increasing the overall number of proteins so far identified in the trophozoite stage by 30% in the previous literature. A relative quantification was obtained for more than 800 proteins. About 5% of proteins showed a clear up- or downregulation upon drug treatment.
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13
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Monteiro WM, Val FFA, Siqueira AM, Franca GP, Sampaio VS, Melo GC, Almeida ACG, Brito MAM, Peixoto HM, Fuller D, Bassat Q, Romero GAS, Maria Regina F O, Marcus Vinícius G L. G6PD deficiency in Latin America: systematic review on prevalence and variants. Mem Inst Oswaldo Cruz 2014; 109:553-68. [PMID: 25141282 PMCID: PMC4156449 DOI: 10.1590/0074-0276140123] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2014] [Accepted: 07/02/2014] [Indexed: 01/14/2023] Open
Abstract
Plasmodium vivax radical cure requires the use of primaquine (PQ), a drug that induces haemolysis in glucose-6-phosphate dehydrogenase deficient (G6PDd) individuals, which further hampers malaria control efforts. The aim of this work was to study the G6PDd prevalence and variants in Latin America (LA) and the Caribbean region. A systematic search of the published literature was undertaken in August 2013. Bibliographies of manuscripts were also searched and additional references were identified. Low prevalence rates of G6PDd were documented in Argentina, Bolivia, Mexico, Peru and Uruguay, but studies from Curaçao, Ecuador, Jamaica, Saint Lucia, Suriname and Trinidad, as well as some surveys carried out in areas of Brazil, Colombia and Cuba, have shown a high prevalence (> 10%) of G6PDd. The G6PD A-202A mutation was the variant most broadly distributed across LA and was identified in 81.1% of the deficient individuals surveyed. G6PDd is a frequent phenomenon in LA, although certain Amerindian populations may not be affected, suggesting that PQ could be safely used in these specific populations. Population-wide use of PQ as part of malaria elimination strategies in LA cannot be supported unless a rapid, accurate and field-deployable G6PDd diagnostic test is made available.
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Affiliation(s)
- Wuelton M Monteiro
- Gerência de Malária, Fundação de Medicina Tropical Dr Heitor Vieira
Dourado, Manaus, AM, Brasil
- Escola Superior de Ciências da Saúde, Universidade do Estado do
Amazonas, Manaus, AM, Brasil
| | - Fernando FA Val
- Gerência de Malária, Fundação de Medicina Tropical Dr Heitor Vieira
Dourado, Manaus, AM, Brasil
- Escola Superior de Ciências da Saúde, Universidade do Estado do
Amazonas, Manaus, AM, Brasil
| | - André M Siqueira
- Gerência de Malária, Fundação de Medicina Tropical Dr Heitor Vieira
Dourado, Manaus, AM, Brasil
- Escola Superior de Ciências da Saúde, Universidade do Estado do
Amazonas, Manaus, AM, Brasil
| | - Gabriel P Franca
- Gerência de Malária, Fundação de Medicina Tropical Dr Heitor Vieira
Dourado, Manaus, AM, Brasil
| | - Vanderson S Sampaio
- Gerência de Malária, Fundação de Medicina Tropical Dr Heitor Vieira
Dourado, Manaus, AM, Brasil
- Escola Superior de Ciências da Saúde, Universidade do Estado do
Amazonas, Manaus, AM, Brasil
| | - Gisely C Melo
- Gerência de Malária, Fundação de Medicina Tropical Dr Heitor Vieira
Dourado, Manaus, AM, Brasil
- Escola Superior de Ciências da Saúde, Universidade do Estado do
Amazonas, Manaus, AM, Brasil
| | - Anne CG Almeida
- Gerência de Malária, Fundação de Medicina Tropical Dr Heitor Vieira
Dourado, Manaus, AM, Brasil
- Escola Superior de Ciências da Saúde, Universidade do Estado do
Amazonas, Manaus, AM, Brasil
| | - Marcelo AM Brito
- Gerência de Malária, Fundação de Medicina Tropical Dr Heitor Vieira
Dourado, Manaus, AM, Brasil
- Escola Superior de Ciências da Saúde, Universidade do Estado do
Amazonas, Manaus, AM, Brasil
| | - Henry M Peixoto
- Faculdade de Medicina, Universidade de Brasília, Brasília, DF,
Brasil
| | - Douglas Fuller
- Department of Geography and Regional Studies, University of Miami, Coral
Gables, FL, USA
| | - Quique Bassat
- Barcelona Centre for International Health Research, Hospital Clinic,
University of Barcelona, Barcelona, Spain
| | - Gustavo AS Romero
- Faculdade de Medicina, Universidade de Brasília, Brasília, DF,
Brasil
- Instituto Nacional de Ciência e Tecnologia para Avaliação de Tecnologias
em Saúde, Porto Alegre, RS, Brasil
| | - Oliveira Maria Regina F
- Faculdade de Medicina, Universidade de Brasília, Brasília, DF,
Brasil
- Instituto Nacional de Ciência e Tecnologia para Avaliação de Tecnologias
em Saúde, Porto Alegre, RS, Brasil
| | - Lacerda Marcus Vinícius G
- Gerência de Malária, Fundação de Medicina Tropical Dr Heitor Vieira
Dourado, Manaus, AM, Brasil
- Escola Superior de Ciências da Saúde, Universidade do Estado do
Amazonas, Manaus, AM, Brasil
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14
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Nunes JK, Woods C, Carter T, Raphael T, Morin MJ, Diallo D, Leboulleux D, Jain S, Loucq C, Kaslow DC, Birkett AJ. Development of a transmission-blocking malaria vaccine: progress, challenges, and the path forward. Vaccine 2014; 32:5531-9. [PMID: 25077422 DOI: 10.1016/j.vaccine.2014.07.030] [Citation(s) in RCA: 63] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2014] [Revised: 06/12/2014] [Accepted: 07/08/2014] [Indexed: 10/25/2022]
Abstract
New interventions are needed to reduce morbidity and mortality associated with malaria, as well as to accelerate elimination and eventual eradication. Interventions that can break the cycle of parasite transmission, and prevent its reintroduction, will be of particular importance in achieving the eradication goal. In this regard, vaccines that interrupt malaria transmission (VIMT) have been highlighted as an important intervention, including transmission-blocking vaccines that prevent human-to-mosquito transmission by targeting the sexual, sporogonic, or mosquito stages of the parasite (SSM-VIMT). While the significant potential of this vaccine approach has been appreciated for decades, the development and licensure pathways for vaccines that target transmission and the incidence of infection, as opposed to prevention of clinical malaria disease, remain ill-defined. This article describes the progress made in critical areas since 2010, highlights key challenges that remain, and outlines important next steps to maximize the potential for SSM-VIMTs to contribute to the broader malaria elimination and eradication objectives.
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Affiliation(s)
- Julia K Nunes
- PATH Malaria Vaccine Initiative, Washington, DC, USA
| | - Colleen Woods
- PATH Malaria Vaccine Initiative, Washington, DC, USA; PATH Malaria Vaccine Initiative, Seattle, WA, USA
| | | | | | | | | | | | - Sanjay Jain
- PATH Malaria Vaccine Initiative, Washington, DC, USA
| | | | - David C Kaslow
- PATH Malaria Vaccine Initiative, Washington, DC, USA; PATH, Seattle, WA, USA
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15
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Liehl P, Zuzarte-Luís V, Chan J, Zillinger T, Baptista F, Carapau D, Konert M, Hanson KK, Carret C, Lassnig C, Müller M, Kalinke U, Saeed M, Chora AF, Golenbock DT, Strobl B, Prudêncio M, Coelho LP, Kappe SH, Superti-Furga G, Pichlmair A, Vigário AM, Rice CM, Fitzgerald KA, Barchet W, Mota MM. Host-cell sensors for Plasmodium activate innate immunity against liver-stage infection. Nat Med 2013; 20:47-53. [PMID: 24362933 DOI: 10.1038/nm.3424] [Citation(s) in RCA: 205] [Impact Index Per Article: 18.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2013] [Accepted: 11/08/2013] [Indexed: 12/15/2022]
Abstract
Before they infect red blood cells and cause malaria, Plasmodium parasites undergo an obligate and clinically silent expansion phase in the liver that is supposedly undetected by the host. Here, we demonstrate the engagement of a type I interferon (IFN) response during Plasmodium replication in the liver. We identified Plasmodium RNA as a previously unrecognized pathogen-associated molecular pattern (PAMP) capable of activating a type I IFN response via the cytosolic pattern recognition receptor Mda5. This response, initiated by liver-resident cells through the adaptor molecule for cytosolic RNA sensors, Mavs, and the transcription factors Irf3 and Irf7, is propagated by hepatocytes in an interferon-α/β receptor-dependent manner. This signaling pathway is critical for immune cell-mediated host resistance to liver-stage Plasmodium infection, which we find can be primed with other PAMPs, including hepatitis C virus RNA. Together, our results show that the liver has sensor mechanisms for Plasmodium that mediate a functional antiparasite response driven by type I IFN.
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Affiliation(s)
- Peter Liehl
- Instituto de Medicina Molecular, Faculdade de Medicina Universidade de Lisboa, Lisboa, Portugal
| | - Vanessa Zuzarte-Luís
- Instituto de Medicina Molecular, Faculdade de Medicina Universidade de Lisboa, Lisboa, Portugal
| | - Jennie Chan
- 1] Department of Medicine, Division of Infectious Diseases and Immunology, University of Massachusetts Medical School, Worcester, Massachusetts, USA. [2]
| | - Thomas Zillinger
- 1] Institute of Clinical Chemistry and Clinical Pharmacology, University Hospital of Bonn, Bonn, Germany. [2]
| | - Fernanda Baptista
- Instituto de Medicina Molecular, Faculdade de Medicina Universidade de Lisboa, Lisboa, Portugal
| | - Daniel Carapau
- Instituto de Medicina Molecular, Faculdade de Medicina Universidade de Lisboa, Lisboa, Portugal
| | - Madlen Konert
- Instituto de Medicina Molecular, Faculdade de Medicina Universidade de Lisboa, Lisboa, Portugal
| | - Kirsten K Hanson
- Instituto de Medicina Molecular, Faculdade de Medicina Universidade de Lisboa, Lisboa, Portugal
| | - Céline Carret
- Instituto de Medicina Molecular, Faculdade de Medicina Universidade de Lisboa, Lisboa, Portugal
| | - Caroline Lassnig
- Institute of Animal Breeding and Genetics and Biomodels, Austria University of Veterinary Medicine Vienna, Vienna, Austria
| | - Mathias Müller
- Institute of Animal Breeding and Genetics and Biomodels, Austria University of Veterinary Medicine Vienna, Vienna, Austria
| | - Ulrich Kalinke
- Institute for Experimental Infection Research, TWINCORE, Centre for Experimental and Clinical Infection Research, Hannover Medical School and Helmholtz Centre for Infection Research, Hannover, Germany
| | - Mohsan Saeed
- Laboratory of Virology and Infectious Diseases, Center for the Study of Hepatitis C, The Rockefeller University, New York, New York, USA
| | - Angelo Ferreira Chora
- Instituto de Medicina Molecular, Faculdade de Medicina Universidade de Lisboa, Lisboa, Portugal
| | - Douglas T Golenbock
- Department of Medicine, Division of Infectious Diseases and Immunology, University of Massachusetts Medical School, Worcester, Massachusetts, USA
| | - Birgit Strobl
- Institute of Animal Breeding and Genetics and Biomodels, Austria University of Veterinary Medicine Vienna, Vienna, Austria
| | - Miguel Prudêncio
- Instituto de Medicina Molecular, Faculdade de Medicina Universidade de Lisboa, Lisboa, Portugal
| | - Luis P Coelho
- Instituto de Medicina Molecular, Faculdade de Medicina Universidade de Lisboa, Lisboa, Portugal
| | - Stefan H Kappe
- Seattle Biomedical Research Institute, Seattle, Washington, USA
| | - Giulio Superti-Furga
- CeMM Research Center for Molecular Medicine of the Austrian Academy of Sciences, Vienna, Austria
| | - Andreas Pichlmair
- CeMM Research Center for Molecular Medicine of the Austrian Academy of Sciences, Vienna, Austria
| | - Ana M Vigário
- 1] Instituto de Medicina Molecular, Faculdade de Medicina Universidade de Lisboa, Lisboa, Portugal. [2] Unidade de Ciências Médicas, Centro de compentência de ciências da vida, Universidade da Madeira, Funchal, Portugal
| | - Charles M Rice
- Laboratory of Virology and Infectious Diseases, Center for the Study of Hepatitis C, The Rockefeller University, New York, New York, USA
| | - Katherine A Fitzgerald
- Department of Medicine, Division of Infectious Diseases and Immunology, University of Massachusetts Medical School, Worcester, Massachusetts, USA
| | - Winfried Barchet
- Institute of Clinical Chemistry and Clinical Pharmacology, University Hospital of Bonn, Bonn, Germany
| | - Maria M Mota
- Instituto de Medicina Molecular, Faculdade de Medicina Universidade de Lisboa, Lisboa, Portugal
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16
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A small molecule glycosaminoglycan mimetic blocks Plasmodium invasion of the mosquito midgut. PLoS Pathog 2013; 9:e1003757. [PMID: 24278017 PMCID: PMC3836724 DOI: 10.1371/journal.ppat.1003757] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2013] [Accepted: 09/25/2013] [Indexed: 11/19/2022] Open
Abstract
Malaria transmission-blocking (T-B) interventions are essential for malaria elimination. Small molecules that inhibit the Plasmodium ookinete-to-oocyst transition in the midgut of Anopheles mosquitoes, thereby blocking sporogony, represent one approach to achieving this goal. Chondroitin sulfate glycosaminoglycans (CS-GAGs) on the Anopheles gambiae midgut surface are putative ligands for Plasmodium falciparum ookinetes. We hypothesized that our synthetic polysulfonated polymer, VS1, acting as a decoy molecular mimetic of midgut CS-GAGs confers malaria T-B activity. In our study, VS1 repeatedly reduced midgut oocyst development by as much as 99% (P<0.0001) in mosquitoes fed with P. falciparum and Plasmodium berghei. Through direct-binding assays, we observed that VS1 bound to two critical ookinete micronemal proteins, each containing at least one von Willebrand factor A (vWA) domain: (i) circumsporozoite protein and thrombospondin-related anonymous protein-related protein (CTRP) and (ii) vWA domain-related protein (WARP). By immunofluorescence microscopy, we observed that VS1 stains permeabilized P. falciparum and P. berghei ookinetes but does not stain P. berghei CTRP knockouts or transgenic parasites lacking the vWA domains of CTRP while retaining the thrombospondin repeat region. We produced structural homology models of the first vWA domain of CTRP and identified, as expected, putative GAG-binding sites on CTRP that align closely with those predicted for the human vWA A1 domain and the Toxoplasma gondii MIC2 adhesin. Importantly, the models also identified patches of electropositive residues that may extend CTRP's GAG-binding motif and thus potentiate VS1 binding. Our molecule binds to a critical, conserved ookinete protein, CTRP, and exhibits potent malaria T-B activity. This study lays the framework for a high-throughput screen of existing libraries of safe compounds to identify those with potent T-B activity. We envision that such compounds when used as partner drugs with current antimalarial regimens and with RTS,S vaccine delivery could prevent the transmission of drug-resistant and vaccine-breakthrough strains. To achieve malaria elimination, the consensus expert opinion is that new approaches to drug and vaccine design are desperately needed. We have undertaken a novel, comprehensive approach towards the development of a malaria transmission-blocking drug based on the strategy of inhibiting Plasmodium development in the mosquito by interfering with obligate cellular interactions between the parasite and the mosquito-midgut epithelium. We have successfully designed a potent transmission-blocking small molecule (VS1) that mimics the structure of molecules on the mosquito-midgut surface called glycosaminoglycans (GAG), which are thought to serve as ligands for parasite attachment prior to cell invasion. Using assays in which mosquitoes were fed with infectious blood, we tested the effect of VS1 on Plasmodium development in the mosquito and found that the GAG mimic dramatically reduced the intensity of infection in the midgut. Binding experiments and immunofluorescence microscopy indicate that VS1 binds to the circumsporozoite- and TRAP-related protein (CTRP), a micronemal protein expressed by ookinetes essential for midgut invasion. This interaction profoundly inhibits a key step of parasite development, thereby abrogating downstream events necessary for mosquito-to-human transmission. The work described lays the framework for bringing a truly novel transmission-blocking drug to fruition.
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17
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In vivo imaging in NHP models of malaria: challenges, progress and outlooks. Parasitol Int 2013; 63:206-15. [PMID: 24042056 PMCID: PMC7108422 DOI: 10.1016/j.parint.2013.09.001] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2012] [Revised: 08/30/2013] [Accepted: 09/06/2013] [Indexed: 12/22/2022]
Abstract
Animal models of malaria, mainly mice, have made a large contribution to our knowledge of host-pathogen interactions and immune responses, and to drug and vaccine design. Non-human primate (NHP) models for malaria are admittedly under-used, although they are probably closer models than mice for human malaria; in particular, NHP models allow the use of human pathogens (Plasmodium falciparum, Plasmodium vivax, Plasmodium malariae and Plasmodium knowlesi). NHPs, whether natural hosts or experimentally challenged with a simian Plasmodium, can also serve as robust pre-clinical models. Some simian parasites are closely related to a human counterpart, with which they may share a common ancestor, and display similar major features with the human infection and pathology. NHP models allow longitudinal studies, from the early events following sporozoite inoculation to the later events, including analysis of organs and tissues, particularly liver, spleen, brain and bone marrow. NHP models have one other significant advantage over mouse models: NHPs are our closest relatives and thus their biology is very similar to ours. Recently developed in vivo imaging tools have provided insight into malaria parasite infection and disease in mouse models. One advantage of these tools is that they limit the need for invasive procedures, such as tissue biopsies. Many such technologies are now available for NHP studies and provide new opportunities for elucidating host/parasite interactions. The aim of this review is to bring the malaria community up to date on what is currently possible and what soon will be, in terms of in vivo imaging in NHP models of malaria, to consider the pros and the cons of the various techniques, and to identify challenges.
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18
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Prommana P, Uthaipibull C, Wongsombat C, Kamchonwongpaisan S, Yuthavong Y, Knuepfer E, Holder AA, Shaw PJ. Inducible knockdown of Plasmodium gene expression using the glmS ribozyme. PLoS One 2013; 8:e73783. [PMID: 24023691 PMCID: PMC3758297 DOI: 10.1371/journal.pone.0073783] [Citation(s) in RCA: 149] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2013] [Accepted: 07/23/2013] [Indexed: 01/07/2023] Open
Abstract
Conventional reverse genetic approaches for study of Plasmodium malaria parasite gene function are limited, or not applicable. Hence, new inducible systems are needed. Here we describe a method to control P. falciparum gene expression in which target genes bearing a glmS ribozyme in the 3' untranslated region are efficiently knocked down in transgenic P. falciparum parasites in response to glucosamine inducer. Using reporter genes, we show that the glmS ribozyme cleaves reporter mRNA in vivo leading to reduction in mRNA expression following glucosamine treatment. Glucosamine-induced ribozyme activation led to efficient reduction of reporter protein, which could be rapidly reversed by removing the inducer. The glmS ribozyme was validated as a reverse-genetic tool by integration into the essential gene and antifolate drug target dihydrofolate reductase-thymidylate synthase (PfDHFR-TS). Glucosamine treatment of transgenic parasites led to rapid and efficient knockdown of PfDHFR-TS mRNA and protein. PfDHFR-TS knockdown led to a growth/arrest mutant phenotype and hypersensitivity to pyrimethamine. The glmS ribozyme may thus be a tool for study of essential genes in P. falciparum and other parasite species amenable to transfection.
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Affiliation(s)
- Parichat Prommana
- National Center for Genetic Engineering and Biotechnology (BIOTEC), Khlong Nueng, Khlong Luang, Pathum Thani, Thailand
| | - Chairat Uthaipibull
- National Center for Genetic Engineering and Biotechnology (BIOTEC), Khlong Nueng, Khlong Luang, Pathum Thani, Thailand
| | - Chayaphat Wongsombat
- National Center for Genetic Engineering and Biotechnology (BIOTEC), Khlong Nueng, Khlong Luang, Pathum Thani, Thailand
| | - Sumalee Kamchonwongpaisan
- National Center for Genetic Engineering and Biotechnology (BIOTEC), Khlong Nueng, Khlong Luang, Pathum Thani, Thailand
| | - Yongyuth Yuthavong
- National Center for Genetic Engineering and Biotechnology (BIOTEC), Khlong Nueng, Khlong Luang, Pathum Thani, Thailand
| | - Ellen Knuepfer
- Division of Parasitology, MRC National Institute for Medical Research, London, United Kingdom
| | - Anthony A. Holder
- Division of Parasitology, MRC National Institute for Medical Research, London, United Kingdom
| | - Philip J. Shaw
- National Center for Genetic Engineering and Biotechnology (BIOTEC), Khlong Nueng, Khlong Luang, Pathum Thani, Thailand
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19
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Burrows JN, van Huijsduijnen RH, Möhrle JJ, Oeuvray C, Wells TNC. Designing the next generation of medicines for malaria control and eradication. Malar J 2013; 12:187. [PMID: 23742293 PMCID: PMC3685552 DOI: 10.1186/1475-2875-12-187] [Citation(s) in RCA: 207] [Impact Index Per Article: 18.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2013] [Accepted: 05/29/2013] [Indexed: 11/10/2022] Open
Abstract
In the fight against malaria new medicines are an essential weapon. For the parts of the world where the current gold standard artemisinin combination therapies are active, significant improvements can still be made: for example combination medicines which allow for single dose regimens, cheaper, safer and more effective medicines, or improved stability under field conditions. For those parts of the world where the existing combinations show less than optimal activity, the priority is to have activity against emerging resistant strains, and other criteria take a secondary role. For new medicines to be optimal in malaria control they must also be able to reduce transmission and prevent relapse of dormant forms: additional constraints on a combination medicine. In the absence of a highly effective vaccine, new medicines are also needed to protect patient populations. In this paper, an outline definition of the ideal and minimally acceptable characteristics of the types of clinical candidate molecule which are needed (target candidate profiles) is suggested. In addition, the optimal and minimally acceptable characteristics of combination medicines are outlined (target product profiles). MMV presents now a suggested framework for combining the new candidates to produce the new medicines. Sustained investment over the next decade in discovery and development of new molecules is essential to enable the long-term delivery of the medicines needed to combat malaria.
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Affiliation(s)
- Jeremy N Burrows
- Medicines for Malaria Venture-MMV, PO Box 1826, Route de Pré-Bois 20, Geneva 151215, Switzerland
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20
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Arnott A, Barnadas C, Senn N, Siba P, Mueller I, Reeder JC, Barry AE. High genetic diversity of Plasmodium vivax on the north coast of Papua New Guinea. Am J Trop Med Hyg 2013; 89:188-94. [PMID: 23690553 DOI: 10.4269/ajtmh.12-0774] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
Despite having the highest Plasmodium vivax burden in the world, molecular epidemiological data from Papua New Guinea (PNG) for this parasite remain limited. To investigate the molecular epidemiology of P. vivax in PNG, 574 isolates collected from four catchment sites in East Sepik (N = 1) and Madang (N = 3) Provinces were genotyped using the markers MS16 and msp1F3. Genetic diversity and prevalence of P. vivax was determined for all sites. Despite a P. vivax infection prevalence in the East Sepik (15%) catchments less than one-half the prevalence of the Madang catchments (27-35%), genetic diversity was similarly high in all populations (He = 0.77-0.98). High genetic diversity, despite a marked difference in infection prevalence, suggests a large reservoir of diversity in P. vivax populations of PNG. Significant reductions in transmission intensity may, therefore, be required to reduce the diversity of parasite populations in highly endemic countries such as PNG.
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Affiliation(s)
- Alicia Arnott
- Walter and Eliza Hall Institute of Medical Research, Melbourne, Australia.
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21
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Noulin F, Borlon C, Van Den Abbeele J, D'Alessandro U, Erhart A. 1912-2012: a century of research on Plasmodium vivax in vitro culture. Trends Parasitol 2013; 29:286-94. [PMID: 23623759 DOI: 10.1016/j.pt.2013.03.012] [Citation(s) in RCA: 73] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2012] [Revised: 03/22/2013] [Accepted: 03/29/2013] [Indexed: 01/17/2023]
Abstract
The development of a continuous Plasmodium vivax blood cycle in vitro was first attempted 100 years ago. Since then, and despite the use of different methods, only short-term cultures have been achieved so far. The available literature has been reviewed in order to provide a critical overview of the currently available knowledge on P. vivax blood cycle culture systems and identify some unexplored ways forward. Results show that data accumulated over the past century remain fragmented and often contradictory, making it difficult to draw conclusions. There is the need for an international consortium on P. vivax culture able to collect, update, and share new evidence, including negative results, and thus better coordinate current efforts towards the establishment of a continuous P. vivax culture.
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Affiliation(s)
- Florian Noulin
- Unit of Malariology, Institute of Tropical Medicine, Antwerp, 2000, Belgium.
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22
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Sundararaman SA, Liu W, Keele BF, Learn GH, Bittinger K, Mouacha F, Ahuka-Mundeke S, Manske M, Sherrill-Mix S, Li Y, Malenke JA, Delaporte E, Laurent C, Mpoudi Ngole E, Kwiatkowski DP, Shaw GM, Rayner JC, Peeters M, Sharp PM, Bushman FD, Hahn BH. Plasmodium falciparum-like parasites infecting wild apes in southern Cameroon do not represent a recurrent source of human malaria. Proc Natl Acad Sci U S A 2013; 110:7020-5. [PMID: 23569255 PMCID: PMC3637760 DOI: 10.1073/pnas.1305201110] [Citation(s) in RCA: 51] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
Abstract
Wild-living chimpanzees and gorillas harbor a multitude of Plasmodium species, including six of the subgenus Laverania, one of which served as the progenitor of Plasmodium falciparum. Despite the magnitude of this reservoir, it is unknown whether apes represent a source of human infections. Here, we used Plasmodium species-specific PCR, single-genome amplification, and 454 sequencing to screen humans from remote areas of southern Cameroon for ape Laverania infections. Among 1,402 blood samples, we found 1,000 to be Plasmodium mitochondrial DNA (mtDNA) positive, all of which contained human parasites as determined by sequencing and/or restriction enzyme digestion. To exclude low-abundance infections, we subjected 514 of these samples to 454 sequencing, targeting a region of the mtDNA genome that distinguishes ape from human Laverania species. Using algorithms specifically developed to differentiate rare Plasmodium variants from 454-sequencing error, we identified single and mixed-species infections with P. falciparum, Plasmodium malariae, and/or Plasmodium ovale. However, none of the human samples contained ape Laverania parasites, including the gorilla precursor of P. falciparum. To characterize further the diversity of P. falciparum in Cameroon, we used single-genome amplification to amplify 3.4-kb mtDNA fragments from 229 infected humans. Phylogenetic analysis identified 62 new variants, all of which clustered with extant P. falciparum, providing further evidence that P. falciparum emerged following a single gorilla-to-human transmission. Thus, unlike Plasmodium knowlesi-infected macaques in southeast Asia, African apes harboring Laverania parasites do not seem to serve as a recurrent source of human malaria, a finding of import to ongoing control and eradication measures.
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Affiliation(s)
- Sesh A. Sundararaman
- Departments of Medicine and
- Microbiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104
| | | | - Brandon F. Keele
- The AIDS and Cancer Virus Program, Science Applications International Corporation–Frederick, Inc., Frederick National Laboratory for Cancer Research, Frederick, MD 21702
| | | | - Kyle Bittinger
- Microbiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104
| | - Fatima Mouacha
- Unité Mixte Internationale 233, Institut de Recherche pour le Développement and University of Montpellier 1, 34394 Montpellier, France
| | - Steve Ahuka-Mundeke
- Unité Mixte Internationale 233, Institut de Recherche pour le Développement and University of Montpellier 1, 34394 Montpellier, France
| | - Magnus Manske
- Sanger Institute Malaria Programme, The Wellcome Trust Sanger Institute, Hinxton, Cambridge CB10 1SA, United Kingdom
| | - Scott Sherrill-Mix
- Microbiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104
| | | | | | - Eric Delaporte
- Unité Mixte Internationale 233, Institut de Recherche pour le Développement and University of Montpellier 1, 34394 Montpellier, France
| | - Christian Laurent
- Unité Mixte Internationale 233, Institut de Recherche pour le Développement and University of Montpellier 1, 34394 Montpellier, France
| | - Eitel Mpoudi Ngole
- Centre de Recherches pour les Maladies Emergents et Ré-émergents and Institut de Recherches Médicales et d'Etudes des Plantes Médicinales, BP 906, Yaoundé, Cameroon; and
| | - Dominic P. Kwiatkowski
- Sanger Institute Malaria Programme, The Wellcome Trust Sanger Institute, Hinxton, Cambridge CB10 1SA, United Kingdom
| | - George M. Shaw
- Departments of Medicine and
- Microbiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104
| | - Julian C. Rayner
- Sanger Institute Malaria Programme, The Wellcome Trust Sanger Institute, Hinxton, Cambridge CB10 1SA, United Kingdom
| | - Martine Peeters
- Unité Mixte Internationale 233, Institut de Recherche pour le Développement and University of Montpellier 1, 34394 Montpellier, France
| | - Paul M. Sharp
- Institute of Evolutionary Biology and Centre for Immunity, Infection and Evolution, University of Edinburgh, Edinburgh EH9 3JT, United Kingdom
| | - Frederic D. Bushman
- Microbiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104
| | - Beatrice H. Hahn
- Departments of Medicine and
- Microbiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104
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23
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Wang S, Jacobs-Lorena M. Genetic approaches to interfere with malaria transmission by vector mosquitoes. Trends Biotechnol 2013; 31:185-93. [PMID: 23395485 PMCID: PMC3593784 DOI: 10.1016/j.tibtech.2013.01.001] [Citation(s) in RCA: 110] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2012] [Revised: 01/03/2013] [Accepted: 01/03/2013] [Indexed: 11/20/2022]
Abstract
Malaria remains one of the most devastating diseases worldwide, causing over 1 million deaths every year. The most vulnerable stages of Plasmodium development in the vector mosquito occur in the midgut lumen, making the midgut a prime target for intervention. Mosquito transgenesis and paratransgenesis are two novel strategies that aim at rendering the vector incapable of sustaining Plasmodium development. Mosquito transgenesis involves direct genetic engineering of the mosquito itself for delivery of anti-Plasmodium effector molecules. Conversely, paratransgenesis involves the genetic modification of mosquito symbionts for expression of anti-pathogen effector molecules. Here we consider both genetic manipulation strategies for rendering mosquitoes refractory to Plasmodium infection, and discuss challenges for the translation of laboratory findings to field applications.
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Affiliation(s)
- Sibao Wang
- Key Laboratory of Insect Developmental and Evolutionary Biology, Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200032, China.
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Transgenic fluorescent Plasmodium cynomolgi liver stages enable live imaging and purification of Malaria hypnozoite-forms. PLoS One 2013; 8:e54888. [PMID: 23359816 PMCID: PMC3554669 DOI: 10.1371/journal.pone.0054888] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2012] [Accepted: 12/17/2012] [Indexed: 01/29/2023] Open
Abstract
A major challenge for strategies to combat the human malaria parasite Plasmodium vivax is the presence of hypnozoites in the liver. These dormant forms can cause renewed clinical disease after reactivation through unknown mechanisms. The closely related non-human primate malaria P. cynomolgi is a frequently used model for studying hypnozoite-induced relapses. Here we report the generation of the first transgenic P. cynomolgi parasites that stably express fluorescent markers in liver stages by transfection with novel DNA-constructs containing a P. cynomolgi centromere. Analysis of fluorescent liver stages in culture identified, in addition to developing liver-schizonts, uninucleate persisting parasites that were atovaquone resistant but primaquine sensitive, features associated with hypnozoites. We demonstrate that these hypnozoite-forms could be isolated by fluorescence-activated cell sorting. The fluorescently-tagged parasites in combination with FACS-purification open new avenues for a wide range of studies for analysing hypnozoite biology and reactivation.
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Abstract
Invasion of the central nervous system (CNS) is a most devastating complication of a parasitic infection. Several physical and immunological barriers provide obstacles to such an invasion. In this broad overview focus is given to the physical barriers to neuroinvasion of parasites provided at the portal of entry of the parasites, i.e., the skin and epithelial cells of the gastrointestinal tract, and between the blood and the brain parenchyma, i.e., the blood-brain barrier (BBB). A description is given on how human pathogenic parasites can reach the CNS via the bloodstream either as free-living or extracellular parasites, by embolization of eggs, or within red or white blood cells when adapted to intracellular life. Molecular mechanisms are discussed by which parasites can interact with or pass across the BBB. The possible targeting of the circumventricular organs by parasites, as well as the parasites' direct entry to the brain from the nasal cavity through the olfactory nerve pathway, is also highlighted. Finally, examples are given which illustrate different mechanisms by which parasites can cause dysfunction or damage in the CNS related to toxic effects of parasite-derived molecules or to immune responses to the infection.
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Wang S, Ghosh AK, Bongio N, Stebbings KA, Lampe DJ, Jacobs-Lorena M. Fighting malaria with engineered symbiotic bacteria from vector mosquitoes. Proc Natl Acad Sci U S A 2012; 109:12734-9. [PMID: 22802646 PMCID: PMC3412027 DOI: 10.1073/pnas.1204158109] [Citation(s) in RCA: 184] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
The most vulnerable stages of Plasmodium development occur in the lumen of the mosquito midgut, a compartment shared with symbiotic bacteria. Here, we describe a strategy that uses symbiotic bacteria to deliver antimalaria effector molecules to the midgut lumen, thus rendering host mosquitoes refractory to malaria infection. The Escherichia coli hemolysin A secretion system was used to promote the secretion of a variety of anti-Plasmodium effector proteins by Pantoea agglomerans, a common mosquito symbiotic bacterium. These engineered P. agglomerans strains inhibited development of the human malaria parasite Plasmodium falciparum and rodent malaria parasite Plasmodium berghei by up to 98%. Significantly, the proportion of mosquitoes carrying parasites (prevalence) decreased by up to 84% for two of the effector molecules, scorpine, a potent antiplasmodial peptide and (EPIP)(4), four copies of Plasmodium enolase-plasminogen interaction peptide that prevents plasminogen binding to the ookinete surface. We demonstrate the use of an engineered symbiotic bacterium to interfere with the development of P. falciparum in the mosquito. These findings provide the foundation for the use of genetically modified symbiotic bacteria as a powerful tool to combat malaria.
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Affiliation(s)
- Sibao Wang
- Department of Molecular Microbiology and Immunology, Malaria Research Institute, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD 21205; and
| | - Anil K. Ghosh
- Department of Molecular Microbiology and Immunology, Malaria Research Institute, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD 21205; and
| | - Nicholas Bongio
- Department of Biological Sciences, Duquesne University, Pittsburgh, PA 15282
| | - Kevin A. Stebbings
- Department of Biological Sciences, Duquesne University, Pittsburgh, PA 15282
| | - David J. Lampe
- Department of Biological Sciences, Duquesne University, Pittsburgh, PA 15282
| | - Marcelo Jacobs-Lorena
- Department of Molecular Microbiology and Immunology, Malaria Research Institute, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD 21205; and
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Martínez-Barnetche J, Gómez-Barreto RE, Ovilla-Muñoz M, Téllez-Sosa J, López DEG, Dinglasan RR, Mohien CU, MacCallum RM, Redmond SN, Gibbons JG, Rokas A, Machado CA, Cazares-Raga FE, González-Cerón L, Hernández-Martínez S, López MHR. Transcriptome of the adult female malaria mosquito vector Anopheles albimanus. BMC Genomics 2012; 13:207. [PMID: 22646700 PMCID: PMC3442982 DOI: 10.1186/1471-2164-13-207] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2012] [Accepted: 05/30/2012] [Indexed: 11/22/2022] Open
Abstract
BACKGROUND Human Malaria is transmitted by mosquitoes of the genus Anopheles. Transmission is a complex phenomenon involving biological and environmental factors of humans, parasites and mosquitoes. Among more than 500 anopheline species, only a few species from different branches of the mosquito evolutionary tree transmit malaria, suggesting that their vectorial capacity has evolved independently. Anopheles albimanus (subgenus Nyssorhynchus) is an important malaria vector in the Americas. The divergence time between Anopheles gambiae, the main malaria vector in Africa, and the Neotropical vectors has been estimated to be 100 My. To better understand the biological basis of malaria transmission and to develop novel and effective means of vector control, there is a need to explore the mosquito biology beyond the An. gambiae complex. RESULTS We sequenced the transcriptome of the An. albimanus adult female. By combining Sanger, 454 and Illumina sequences from cDNA libraries derived from the midgut, cuticular fat body, dorsal vessel, salivary gland and whole body, we generated a single, high-quality assembly containing 16,669 transcripts, 92% of which mapped to the An. darlingi genome and covered 90% of the core eukaryotic genome. Bidirectional comparisons between the An. gambiae, An. darlingi and An. albimanus predicted proteomes allowed the identification of 3,772 putative orthologs. More than half of the transcripts had a match to proteins in other insect vectors and had an InterPro annotation. We identified several protein families that may be relevant to the study of Plasmodium-mosquito interaction. An open source transcript annotation browser called GDAV (Genome-Delinked Annotation Viewer) was developed to facilitate public access to the data generated by this and future transcriptome projects. CONCLUSIONS We have explored the adult female transcriptome of one important New World malaria vector, An. albimanus. We identified protein-coding transcripts involved in biological processes that may be relevant to the Plasmodium lifecycle and can serve as the starting point for searching targets for novel control strategies. Our data increase the available genomic information regarding An. albimanus several hundred-fold, and will facilitate molecular research in medical entomology, evolutionary biology, genomics and proteomics of anopheline mosquito vectors. The data reported in this manuscript is accessible to the community via the VectorBase website (http://www.vectorbase.org/Other/AdditionalOrganisms/).
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Affiliation(s)
- Jesús Martínez-Barnetche
- Centro de Investigación sobre Enfermedades Infecciosas, Instituto Nacional de Salud Pública, Cuernavaca, Morelos, México
| | - Rosa E Gómez-Barreto
- Centro de Investigación sobre Enfermedades Infecciosas, Instituto Nacional de Salud Pública, Cuernavaca, Morelos, México
| | - Marbella Ovilla-Muñoz
- Centro de Investigación sobre Enfermedades Infecciosas, Instituto Nacional de Salud Pública, Cuernavaca, Morelos, México
| | - Juan Téllez-Sosa
- Centro de Investigación sobre Enfermedades Infecciosas, Instituto Nacional de Salud Pública, Cuernavaca, Morelos, México
| | - David E García López
- Centro de Investigación sobre Enfermedades Infecciosas, Instituto Nacional de Salud Pública, Cuernavaca, Morelos, México
| | - Rhoel R Dinglasan
- Johns Hopkins Bloomberg School of Public Health. Department of Molecular Microbiology & Immunology, Johns Hopkins Malaria Research Institute, Baltimore, MD, 21205, USA
| | - Ceereena Ubaida Mohien
- Johns Hopkins Bloomberg School of Public Health. Department of Molecular Microbiology & Immunology, Johns Hopkins Malaria Research Institute, Baltimore, MD, 21205, USA
- Department of Molecular & Comparative Pathobiology, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Robert M MacCallum
- Division of Cell and Molecular Biology, Department of Life Sciences, Imperial College London, London, United Kingdom
| | - Seth N Redmond
- Pasteur Institut, 28 Rue Du Docteur Roux, Paris, 75015, France
| | - John G Gibbons
- Department of Biological Sciences, Vanderbilt University, Nashville, TN, USA
| | - Antonis Rokas
- Department of Biological Sciences, Vanderbilt University, Nashville, TN, USA
| | - Carlos A Machado
- Department of Biology, University of Maryland, College Park, MD, USA
| | - Febe E Cazares-Raga
- Departamento de Infectómica y Patogénesis Molecular, Cinvestav-IPN, México, DF, México
| | - Lilia González-Cerón
- Centro Regional de Investigación en Salud Pública, Instituto Nacional de Salud Pública, Tapachula, Chiapas, México
| | - Salvador Hernández-Martínez
- Centro de Investigación sobre Enfermedades Infecciosas, Instituto Nacional de Salud Pública, Cuernavaca, Morelos, México
| | - Mario H Rodríguez López
- Centro de Investigación sobre Enfermedades Infecciosas, Instituto Nacional de Salud Pública, Cuernavaca, Morelos, México
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28
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Innate recognition of malarial parasites by mammalian hosts. Int J Parasitol 2012; 42:557-66. [DOI: 10.1016/j.ijpara.2012.04.006] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2012] [Revised: 04/11/2012] [Accepted: 04/13/2012] [Indexed: 12/22/2022]
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29
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Lustigman S, Geldhof P, Grant WN, Osei-Atweneboana MY, Sripa B, Basáñez MG. A research agenda for helminth diseases of humans: basic research and enabling technologies to support control and elimination of helminthiases. PLoS Negl Trop Dis 2012; 6:e1445. [PMID: 22545160 PMCID: PMC3335859 DOI: 10.1371/journal.pntd.0001445] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Successful and sustainable intervention against human helminthiases depends on optimal utilisation of available control measures and development of new tools and strategies, as well as an understanding of the evolutionary implications of prolonged intervention on parasite populations and those of their hosts and vectors. This will depend largely on updated knowledge of relevant and fundamental parasite biology. There is a need, therefore, to exploit and apply new knowledge and techniques in order to make significant and novel gains in combating helminthiases and supporting the sustainability of current and successful mass drug administration (MDA) programmes. Among the fields of basic research that are likely to yield improved control tools, the Disease Reference Group on Helminth Infections (DRG4) has identified four broad areas that stand out as central to the development of the next generation of helminth control measures: 1) parasite genetics, genomics, and functional genomics; 2) parasite immunology; 3) (vertebrate) host–parasite interactions and immunopathology; and 4) (invertebrate) host–parasite interactions and transmission biology. The DRG4 was established in 2009 by the Special Programme for Research and Training in Tropical Diseases (TDR). The Group was given the mandate to undertake a comprehensive review of recent advances in helminthiases research in order to identify notable gaps and highlight priority areas. This paper summarises recent advances and discusses challenges in the investigation of the fundamental biology of those helminth parasites under the DRG4 Group's remit according to the identified priorities, and presents a research and development agenda for basic parasite research and enabling technologies that will help support control and elimination efforts against human helminthiases.
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Affiliation(s)
- Sara Lustigman
- Laboratory of Molecular Parasitology, Lindsley F. Kimball Research Institute, New York Blood Center, New York, New York, USA.
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30
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Affiliation(s)
- Jürg Utzinger
- Department of Epidemiology and Public Health, Swiss Tropical and Public Health Institute, Basel, Switzerland
- University of Basel, Basel, Switzerland
- * E-mail:
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31
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Mnyone LL, Lyimo IN, Lwetoijera DW, Mpingwa MW, Nchimbi N, Hancock PA, Russell TL, Kirby MJ, Takken W, Koenraadt CJM. Exploiting the behaviour of wild malaria vectors to achieve high infection with fungal biocontrol agents. Malar J 2012; 11:87. [PMID: 22449130 PMCID: PMC3337815 DOI: 10.1186/1475-2875-11-87] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2012] [Accepted: 03/26/2012] [Indexed: 12/20/2022] Open
Abstract
BACKGROUND Control of mosquitoes that transmit malaria has been the mainstay in the fight against the disease, but alternative methods are required in view of emerging insecticide resistance. Entomopathogenic fungi are candidate alternatives, but to date, few trials have translated the use of these agents to field-based evaluations of their actual impact on mosquito survival and malaria risk. Mineral oil-formulations of the entomopathogenic fungi Metarhizium anisopliae and Beauveria bassiana were applied using five different techniques that each exploited the behaviour of malaria mosquitoes when entering, host-seeking or resting in experimental huts in a malaria endemic area of rural Tanzania. RESULTS Survival of mosquitoes was reduced by 39-57% relative to controls after forcing upward house-entry of mosquitoes through fungus treated baffles attached to the eaves or after application of fungus-treated surfaces around an occupied bed net (bed net strip design). Moreover, 68 to 76% of the treatment mosquitoes showed fungal growth and thus had sufficient contact with fungus treated surfaces. A population dynamic model of malaria-mosquito interactions shows that these infection rates reduce malaria transmission by 75-80% due to the effect of fungal infection on adult mortality alone. The model also demonstrated that even if a high proportion of the mosquitoes exhibits outdoor biting behaviour, malaria transmission was still significantly reduced. CONCLUSIONS Entomopathogenic fungi strongly affect mosquito survival and have a high predicted impact on malaria transmission. These entomopathogens represent a viable alternative for malaria control, especially if they are used as part of an integrated vector management strategy.
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Affiliation(s)
- Ladslaus L Mnyone
- Biomedical and Environmental Group, Ifakara Health Institute, P.O. Box 53, Off Mlabani Passage, Ifakara, Tanzania
- Laboratory of Entomology, Wageningen University and Research Centre, P.O. Box 8031, 6700 EH Wageningen, The Netherlands
- Pest Management Centre, Sokoine University of Agriculture, P.O. Box 3110, Morogoro, Tanzania
| | - Issa N Lyimo
- Biomedical and Environmental Group, Ifakara Health Institute, P.O. Box 53, Off Mlabani Passage, Ifakara, Tanzania
- Faculty of Biomedical and Life Sciences, University of Glasgow, 120 University Place, G12 8TA Glasgow, UK
| | - Dickson W Lwetoijera
- Biomedical and Environmental Group, Ifakara Health Institute, P.O. Box 53, Off Mlabani Passage, Ifakara, Tanzania
| | - Monica W Mpingwa
- Biomedical and Environmental Group, Ifakara Health Institute, P.O. Box 53, Off Mlabani Passage, Ifakara, Tanzania
| | - Nuru Nchimbi
- Biomedical and Environmental Group, Ifakara Health Institute, P.O. Box 53, Off Mlabani Passage, Ifakara, Tanzania
| | | | - Tanya L Russell
- Biomedical and Environmental Group, Ifakara Health Institute, P.O. Box 53, Off Mlabani Passage, Ifakara, Tanzania
- The University of Queensland, School of Population Health, Australian Centre for Tropical and International Health, Brisbane 4006, Australia
- Vector Group, Liverpool School of Tropical Medicine, Liverpool L3 5QA, UK
| | - Matthew J Kirby
- Biomedical and Environmental Group, Ifakara Health Institute, P.O. Box 53, Off Mlabani Passage, Ifakara, Tanzania
- Laboratory of Entomology, Wageningen University and Research Centre, P.O. Box 8031, 6700 EH Wageningen, The Netherlands
| | - Willem Takken
- Laboratory of Entomology, Wageningen University and Research Centre, P.O. Box 8031, 6700 EH Wageningen, The Netherlands
| | - Constantianus JM Koenraadt
- Laboratory of Entomology, Wageningen University and Research Centre, P.O. Box 8031, 6700 EH Wageningen, The Netherlands
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Expression, immunogenicity, histopathology, and potency of a mosquito-based malaria transmission-blocking recombinant vaccine. Infect Immun 2012; 80:1606-14. [PMID: 22311924 DOI: 10.1128/iai.06212-11] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
Vaccines have been at the forefront of global research efforts to combat malaria, yet despite several vaccine candidates, this goal has yet to be realized. A potentially effective approach to disrupting the spread of malaria is the use of transmission-blocking vaccines (TBV), which prevent the development of malarial parasites within their mosquito vector, thereby abrogating the cascade of secondary infections in humans. Since malaria is transmitted to human hosts by the bite of an obligate insect vector, mosquito species in the genus Anopheles, targeting mosquito midgut antigens that serve as ligands for Plasmodium parasites represents a promising approach to breaking the transmission cycle. The midgut-specific anopheline alanyl aminopeptidase N (AnAPN1) is highly conserved across Anopheles vectors and is a putative ligand for Plasmodium ookinete invasion. We have developed a scalable, high-yield Escherichia coli expression and purification platform for the recombinant AnAPN1 TBV antigen and report on its marked vaccine potency and immunogenicity, its capacity for eliciting transmission-blocking antibodies, and its apparent lack of immunization-associated histopathologies in a small-animal model.
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33
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Breman JG, Brandling-Bennett AD. The challenge of malaria eradication in the twenty-first century: research linked to operations is the key. Vaccine 2012; 29 Suppl 4:D97-103. [PMID: 22284402 DOI: 10.1016/j.vaccine.2011.12.003] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2011] [Revised: 11/24/2011] [Accepted: 12/01/2011] [Indexed: 10/14/2022]
Abstract
Interest and support for malaria control, eradication, and research has increased greatly over the past decade. This has resulted from appreciation of the huge medical, social, and economic burden that malaria exacts from endemic populations. Recent breakthroughs in drug development (artemisinin-based combination treatments), preventive interventions (long-lasting, insecticide-treated bed nets), improved diagnosis (rapid diagnostic tests), and community mobilization have resulted in deployment of new antimalarial tools. National programs supported by the Global Fund to Fight AIDS, Tuberculosis and Malaria, the U.S. President's Malaria Initiative, and other donors have resulted in substantial reductions in malaria morbidity and mortality. Bill and Melinda Gates have given great impetus to eradication with support for the development of key research strategies and direct funding of innovative research projects, including malaria vaccine and drug discovery, that could decrease disease and transmission. Linking research to field operations is a strategy that succeeded for smallpox eradication and will be required for the demise of malaria.
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Affiliation(s)
- Joel G Breman
- Fogarty International Center, National Institutes of Health, 16 Center Drive, Bethesda, MD 20892, USA.
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34
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Arnott A, Barry AE, Reeder JC. Understanding the population genetics of Plasmodium vivax is essential for malaria control and elimination. Malar J 2012; 11:14. [PMID: 22233585 PMCID: PMC3298510 DOI: 10.1186/1475-2875-11-14] [Citation(s) in RCA: 85] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2011] [Accepted: 01/10/2012] [Indexed: 11/22/2022] Open
Abstract
Traditionally, infection with Plasmodium vivax was thought to be benign and self-limiting, however, recent evidence has demonstrated that infection with P. vivax can also result in severe illness and death. Research into P. vivax has been relatively neglected and much remains unknown regarding the biology, pathogenesis and epidemiology of this parasite. One of the fundamental factors governing transmission and immunity is parasite diversity. An understanding of parasite population genetic structure is necessary to understand the epidemiology, diversity, distribution and dynamics of natural P. vivax populations. In addition, studying the population structure of genes under immune selection also enables investigation of the dynamic interplay between transmission and immunity, which is crucial for vaccine development. A lack of knowledge regarding the transmission and spread of P. vivax has been particularly highlighted in areas where malaria control and elimination programmes have made progress in reducing the burden of Plasmodium falciparum, yet P. vivax remains as a substantial obstacle. With malaria elimination back on the global agenda, mapping of global and local P. vivax population structure is essential prior to establishing goals for elimination and the roll-out of interventions. A detailed knowledge of the spatial distribution, transmission and clinical burden of P. vivax is required to act as a benchmark against which control targets can be set and measured. This paper presents an overview of what is known and what is yet to be fully understood regarding P. vivax population genetics, as well as the importance and application of P. vivax population genetics studies.
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Affiliation(s)
- Alicia Arnott
- Centre for Population Health, Burnet Institute, Melbourne, Australia
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35
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Superinfection in malaria: Plasmodium shows its iron will. EMBO Rep 2011; 12:1233-42. [PMID: 22081142 DOI: 10.1038/embor.2011.213] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2011] [Accepted: 09/30/2011] [Indexed: 12/21/2022] Open
Abstract
After the bite of a malaria-infected mosquito, the Plasmodium sporozoite infects liver cells and produces thousands of merozoites, which then infect red blood cells, causing malaria. In malaria-endemic areas, several hundred infected mosquitoes can bite an individual each year, increasing the risk of superinfection. However, in infants that are yet to acquire immunity, superinfections are infrequent. We have recently shown that blood-stage parasitaemia, above a minimum threshold, impairs the growth of a subsequent sporozoite infection of liver cells. Blood-stage parasites stimulate the production of the host iron-regulatory factor hepcidin, which redistributes iron away from hepatocytes, reducing the development of the iron-dependent liver stage. This could explain why Plasmodium superinfection is not often found in young nonimmune children. Here, we discuss the impact that such protection from superinfection might have in epidemiological settings or in programmes for controlling malaria, as well as how the induction of hepcidin and redistribution of iron might influence anaemia and the outcome of non-Plasmodium co-infections.
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36
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Markus MB. Dormancy in mammalian malaria. Trends Parasitol 2011; 28:39-45. [PMID: 22118814 DOI: 10.1016/j.pt.2011.10.005] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2011] [Revised: 10/15/2011] [Accepted: 10/18/2011] [Indexed: 11/26/2022]
Abstract
This analysis principally concerns biological aspects of dormancy in mammalian malaria, with particular reference to the hypnozoite. Research is needed to reveal what happens to sporozoites of Plasmodium cynomolgi between the time of inoculation and when hypnozoites are first seen in the liver 36-40 h later. It is likely that hypnozoites of relapsing malarial parasites will prove to be directly sporozoite-derived rather than merozoite-derived. There is indirect evidence that, contrary to what is generally assumed, activation of hypnozoites might not be the only cause of recurrent Plasmodium vivax malaria. Latent stages pose a threat to success in eradicating malaria; some suggestions are therefore made for demystifying work on hypnozoites and quiescent merozoites.
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Affiliation(s)
- Miles B Markus
- School of Animal, Plant and Environmental Sciences, University of Witwatersrand, Johannesburg, South Africa.
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37
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Huijben S, Sim DG, Nelson WA, Read AF. The fitness of drug-resistant malaria parasites in a rodent model: multiplicity of infection. J Evol Biol 2011; 24:2410-22. [PMID: 21883612 PMCID: PMC3304104 DOI: 10.1111/j.1420-9101.2011.02369.x] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
Malaria infections normally consist of more than one clonally replicating lineage. Within-host interactions between sensitive and resistant parasites can have profound effects on the evolution of drug resistance. Here, using the Plasmodium chabaudi mouse malaria model, we ask whether the costs and benefits of resistance are affected by the number of co-infecting strains competing with a resistant clone. We found strong competitive suppression of resistant parasites in untreated infections and marked competitive release following treatment. The magnitude of competitive suppression depended on competitor identity. However, there was no overall effect of the diversity of susceptible parasites on the extent of competitive suppression or release. If these findings generalize, then transmission intensity will impact on resistance evolution because of its effect on the frequency of mixed infections, not because of its effect on the distribution of clones per host. This would greatly simplify the computational problems of adequately capturing within-host ecology in models of drug resistance evolution in malaria.
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Affiliation(s)
- S Huijben
- Department of Biology, Center for Infectious Disease Dynamics, Pennsylvania State University, University Park, PA 16802, USA.
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38
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Prudêncio M, Mota MM, Mendes AM. A toolbox to study liver stage malaria. Trends Parasitol 2011; 27:565-74. [PMID: 22015112 DOI: 10.1016/j.pt.2011.09.004] [Citation(s) in RCA: 96] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2011] [Revised: 09/09/2011] [Accepted: 09/20/2011] [Indexed: 01/28/2023]
Abstract
The first obligatory phase of mammalian infection by Plasmodium parasites, the causative agents of malaria, occurs in the liver of the host. This stage of Plasmodium infection bears enormous potential for anti-malarial intervention. Recent technological progress has strongly contributed to overcoming some of the long-standing difficulties in experimentally assessing hepatic infection by Plasmodium. Here, we review appropriate infection models and infection assessment tools, and provide a comprehensive description of recent advances in experimental strategies to investigate the liver stage of malaria. These issues are discussed in the context of current challenges in the field to provide researchers with the technical tools that enable effective experimental approaches to study liver stage malaria.
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Affiliation(s)
- Miguel Prudêncio
- Unidade de Malária, Instituto de Medicina Molecular, Faculdade de Medicina da Universidade de Lisboa, Av. Prof. Egas Moniz, 1649-028 Lisboa, Portugal.
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39
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Abstract
Malaria modeling can inform policy and guide research for malaria elimination and eradication from local implementation to global policy. A research and development agenda for malaria modeling is proposed, to support operations and to enhance the broader eradication research agenda. Models are envisioned as an integral part of research, planning, and evaluation, and modelers should ideally be integrated into multidisciplinary teams to update the models iteratively, communicate their appropriate use, and serve the needs of other research scientists, public health specialists, and government officials. A competitive and collaborative framework will result in policy recommendations from multiple, independently derived models and model systems that share harmonized databases. As planned, modeling results will be produced in five priority areas: (1) strategic planning to determine where and when resources should be optimally allocated to achieve eradication; (2) management plans to minimize the evolution of drug and pesticide resistance; (3) impact assessments of new and needed tools to interrupt transmission; (4) technical feasibility assessments to determine appropriate combinations of tools, an associated set of target intervention coverage levels, and the expected timelines for achieving a set of goals in different socio-ecological settings and different health systems; and (5) operational feasibility assessments to weigh the economic costs, capital investments, and human resource capacities required.
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Abstract
Vaccines could be a crucial component of efforts to eradicate malaria. Current attempts to develop malaria vaccines are primarily focused on Plasmodium falciparum and are directed towards reducing morbidity and mortality. Continued support for these efforts is essential, but if malaria vaccines are to be used as part of a repertoire of tools for elimination or eradication of malaria, they will need to have an impact on malaria transmission. We introduce the concept of "vaccines that interrupt malaria transmission" (VIMT), which includes not only "classical" transmission-blocking vaccines that target the sexual and mosquito stages but also pre-erythrocytic and asexual stage vaccines that have an effect on transmission. VIMT may also include vaccines that target the vector to disrupt parasite development in the mosquito. Importantly, if eradication is to be achieved, malaria vaccine development efforts will need to target other malaria parasite species, especially Plasmodium vivax, where novel therapeutic vaccines against hypnozoites or preventive vaccines with effect against multiple stages could have enormous impact. A target product profile (TPP) for VIMT is proposed and a research agenda to address current knowledge gaps and develop tools necessary for design and development of VIMT is presented.
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Alonso PL, Brown G, Arevalo-Herrera M, Binka F, Chitnis C, Collins F, Doumbo OK, Greenwood B, Hall BF, Levine MM, Mendis K, Newman RD, Plowe CV, Rodríguez MH, Sinden R, Slutsker L, Tanner M. A research agenda to underpin malaria eradication. PLoS Med 2011; 8:e1000406. [PMID: 21311579 PMCID: PMC3026687 DOI: 10.1371/journal.pmed.1000406] [Citation(s) in RCA: 487] [Impact Index Per Article: 37.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
The interruption of malaria transmission worldwide is one of the greatest challenges for international health and development communities. The current expert view suggests that, by aggressively scaling up control with currently available tools and strategies, much greater gains could be achieved against malaria, including elimination from a number of countries and regions; however, even with maximal effort we will fall short of global eradication. The Malaria Eradication Research Agenda (malERA) complements the current research agenda--primarily directed towards reducing morbidity and mortality--with one that aims to identify key knowledge gaps and define the strategies and tools that will result in reducing the basic reproduction rate to less than 1, with the ultimate aim of eradication of the parasite from the human population. Sustained commitment from local communities, civil society, policy leaders, and the scientific community, together with a massive effort to build a strong base of researchers from the endemic areas will be critical factors in the success of this new agenda.
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Affiliation(s)
- Pedro L Alonso
- Barcelona Centre for International Health Research (Hospital Clínic, Universitat de Barcelona), Barcelona, Spain.
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42
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Abstract
Many of malaria's signs and symptoms are indistinguishable from those of other febrile diseases. Detection of the presence of Plasmodium parasites is essential, therefore, to guide case management. Improved diagnostic tools are required to enable targeted treatment of infected individuals. In addition, field-ready diagnostic tools for mass screening and surveillance that can detect asymptomatic infections of very low parasite densities are needed to monitor transmission reduction and ensure elimination. Antibody-based tests for infection and novel methods based on biomarkers need further development and validation, as do methods for the detection and treatment of Plasmodium vivax. Current rapid diagnostic tests targeting P. vivax are generally less effective than those targeting Plasmodium falciparum. Moreover, because current drugs for radical cure may cause serious side effects in patients with glucose-6-phosphate dehydrogenase (G6PD) deficiency, more information is needed on the distribution of G6PD-deficiency variants as well as tests to identify at-risk individuals. Finally, in an environment of very low or absent malaria transmission, sustaining interest in elimination and maintaining resources will become increasingly important. Thus, research is required into the context in which malaria diagnostic tests are used, into diagnostics for other febrile diseases, and into the integration of these tests into health systems.
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