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Mahindra A, Janha O, Mapesa K, Sanchez-Azqueta A, Alam MM, Amambua-Ngwa A, Nwakanma DC, Tobin AB, Jamieson AG. Development of Potent PfCLK3 Inhibitors Based on TCMDC-135051 as a New Class of Antimalarials. J Med Chem 2020; 63:9300-9315. [PMID: 32787140 PMCID: PMC7497403 DOI: 10.1021/acs.jmedchem.0c00451] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2020] [Indexed: 12/20/2022]
Abstract
The protein kinase PfCLK3 plays a critical role in the regulation of malarial parasite RNA splicing and is essential for the survival of blood stage Plasmodium falciparum. We recently validated PfCLK3 as a drug target in malaria that offers prophylactic, transmission blocking, and curative potential. Herein, we describe the synthesis of our initial hit TCMDC-135051 (1) and efforts to establish a structure-activity relationship with a 7-azaindole-based series. A total of 14 analogues were assessed in a time-resolved fluorescence energy transfer assay against the full-length recombinant protein kinase PfCLK3, and 11 analogues were further assessed in asexual 3D7 (chloroquine-sensitive) strains of P. falciparum parasites. SAR relating to rings A and B was established. These data together with analysis of activity against parasites collected from patients in the field suggest that TCMDC-135051 (1) is a promising lead compound for the development of new antimalarials with a novel mechanism of action targeting PfCLK3.
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Affiliation(s)
- Amit Mahindra
- School
of Chemistry, University of Glasgow, Joseph Black Building, University
Avenue, Glasgow G12 8QQ, U.K.
| | - Omar Janha
- Centre
for Translational Pharmacology, Institute of Molecular Cell and Systems Biology, University of Glasgow, Davidson Building, Glasgow G12 8QQ, U.K.
| | - Kopano Mapesa
- School
of Chemistry, University of Glasgow, Joseph Black Building, University
Avenue, Glasgow G12 8QQ, U.K.
| | - Ana Sanchez-Azqueta
- Centre
for Translational Pharmacology, Institute of Molecular Cell and Systems Biology, University of Glasgow, Davidson Building, Glasgow G12 8QQ, U.K.
| | - Mahmood M. Alam
- Wellcome
Centre for Integrative Parasitology and Centre for Translational Pharmacology,
Institute of Infection Immunity and Inflammation, University of Glasgow, Glasgow G12 8TA, U.K.
| | - Alfred Amambua-Ngwa
- MRC
Unit The Gambia at LSHTM, Atlantic Boulevard,
Fajara, P. O. Box 273, Banjul, The Gambia
| | - Davis C. Nwakanma
- MRC
Unit The Gambia at LSHTM, Atlantic Boulevard,
Fajara, P. O. Box 273, Banjul, The Gambia
| | - Andrew B. Tobin
- Centre
for Translational Pharmacology, Institute of Molecular Cell and Systems Biology, University of Glasgow, Davidson Building, Glasgow G12 8QQ, U.K.
| | - Andrew G. Jamieson
- School
of Chemistry, University of Glasgow, Joseph Black Building, University
Avenue, Glasgow G12 8QQ, U.K.
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Alam MM, Sanchez-Azqueta A, Janha O, Flannery EL, Mahindra A, Mapesa K, Char AB, Sriranganadane D, Brancucci NMB, Antonova-Koch Y, Crouch K, Simwela NV, Millar SB, Akinwale J, Mitcheson D, Solyakov L, Dudek K, Jones C, Zapatero C, Doerig C, Nwakanma DC, Vázquez MJ, Colmenarejo G, Lafuente-Monasterio MJ, Leon ML, Godoi PHC, Elkins JM, Waters AP, Jamieson AG, Álvaro EF, Ranford-Cartwright LC, Marti M, Winzeler EA, Gamo FJ, Tobin AB. Validation of the protein kinase PfCLK3 as a multistage cross-species malarial drug target. Science 2019; 365:365/6456/eaau1682. [PMID: 31467193 DOI: 10.1126/science.aau1682] [Citation(s) in RCA: 34] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2018] [Revised: 03/15/2019] [Accepted: 07/12/2019] [Indexed: 12/26/2022]
Abstract
The requirement for next-generation antimalarials to be both curative and transmission-blocking necessitates the identification of previously undiscovered druggable molecular pathways. We identified a selective inhibitor of the Plasmodium falciparum protein kinase PfCLK3, which we used in combination with chemogenetics to validate PfCLK3 as a drug target acting at multiple parasite life stages. Consistent with a role for PfCLK3 in RNA splicing, inhibition resulted in the down-regulation of more than 400 essential parasite genes. Inhibition of PfCLK3 mediated rapid killing of asexual liver- and blood-stage P. falciparum and blockade of gametocyte development, thereby preventing transmission, and also showed parasiticidal activity against P. berghei and P. knowlesi Hence, our data establish PfCLK3 as a target for drugs, with the potential to offer a cure-to be prophylactic and transmission blocking in malaria.
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Affiliation(s)
- Mahmood M Alam
- Wellcome Centre for Integrative Parasitology, University of Glasgow, Glasgow G12 8QQ, UK
| | - Ana Sanchez-Azqueta
- Centre for Translational Pharmacology, Institute of Molecular Cell and Systems Biology, University of Glasgow, Glasgow G12 8QQ, UK
| | - Omar Janha
- Centre for Translational Pharmacology, Institute of Molecular Cell and Systems Biology, University of Glasgow, Glasgow G12 8QQ, UK
| | - Erika L Flannery
- Novartis Institute for Biomedical Research, Emeryville, CA 94608, USA
| | - Amit Mahindra
- School of Chemistry, University of Glasgow, Glasgow G12 8QQ, UK
| | - Kopano Mapesa
- School of Chemistry, University of Glasgow, Glasgow G12 8QQ, UK
| | - Aditya B Char
- Institute of Biodiversity, Animal Health and Comparative Medicine, College of Medical, Veterinary and Life Science, University of Glasgow, Glasgow G12 8QQ, UK
| | - Dev Sriranganadane
- Structural Genomics Consortium, Universidade Estadual de Campinas, Campinas, São Paulo 13083-886, Brazil
| | - Nicolas M B Brancucci
- Department of Medical Parasitology and Infection Biology, Swiss Tropical and Public Health Institute, 4051 Basel, Switzerland
| | - Yevgeniya Antonova-Koch
- Skaggs School of Pharmaceutical Sciences, UC Health Sciences Center for Immunology, Infection and Inflammation, University of California, San Diego, School of Medicine, La Jolla, CA 92093, USA
| | - Kathryn Crouch
- Wellcome Centre for Integrative Parasitology, University of Glasgow, Glasgow G12 8QQ, UK
| | - Nelson Victor Simwela
- Wellcome Centre for Integrative Parasitology, University of Glasgow, Glasgow G12 8QQ, UK
| | - Scott B Millar
- Wellcome Centre for Integrative Parasitology, University of Glasgow, Glasgow G12 8QQ, UK
| | - Jude Akinwale
- Medical Research Council Toxicology Unit, University of Leicester, Leicester LE1 9HN, UK
| | - Deborah Mitcheson
- Department of Molecular Cell Biology, University of Leicester, Leicester LE1 9HN, UK
| | - Lev Solyakov
- Medical Research Council Toxicology Unit, University of Leicester, Leicester LE1 9HN, UK
| | - Kate Dudek
- Medical Research Council Toxicology Unit, University of Leicester, Leicester LE1 9HN, UK
| | - Carolyn Jones
- Medical Research Council Toxicology Unit, University of Leicester, Leicester LE1 9HN, UK
| | - Cleofé Zapatero
- Diseases of the Developing World, GlaxoSmithKline, 28760 Tres Cantos, Madrid, Spain
| | - Christian Doerig
- Biomedical Science Cluster, School of Health and Biomedical Sciences, Royal Melbourne Institute of Technology, Melbourne, VIC 3000, Australia
| | | | - Maria Jesús Vázquez
- Diseases of the Developing World, GlaxoSmithKline, 28760 Tres Cantos, Madrid, Spain
| | - Gonzalo Colmenarejo
- Biostatistics and Bioinformatics Unit, IMDEA Food Institute, 28049 Madrid, Spain
| | | | - Maria Luisa Leon
- Diseases of the Developing World, GlaxoSmithKline, 28760 Tres Cantos, Madrid, Spain
| | - Paulo H C Godoi
- Structural Genomics Consortium, Universidade Estadual de Campinas, Campinas, São Paulo 13083-886, Brazil
| | - Jon M Elkins
- Structural Genomics Consortium, Nuffield Department of Clinical Medicine, University of Oxford, Oxford OX3 7DQ, UK
| | - Andrew P Waters
- Wellcome Centre for Integrative Parasitology, University of Glasgow, Glasgow G12 8QQ, UK
| | | | | | - Lisa C Ranford-Cartwright
- Institute of Biodiversity, Animal Health and Comparative Medicine, College of Medical, Veterinary and Life Science, University of Glasgow, Glasgow G12 8QQ, UK
| | - Matthias Marti
- Wellcome Centre for Integrative Parasitology, University of Glasgow, Glasgow G12 8QQ, UK
| | - Elizabeth A Winzeler
- Skaggs School of Pharmaceutical Sciences, UC Health Sciences Center for Immunology, Infection and Inflammation, University of California, San Diego, School of Medicine, La Jolla, CA 92093, USA
| | | | - Andrew B Tobin
- Centre for Translational Pharmacology, Institute of Molecular Cell and Systems Biology, University of Glasgow, Glasgow G12 8QQ, UK.
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Mukudu H, Martinson N, Sartorius B, Coetzee J, Dietrich J, Mokgatswana K, Jewkes R, Gray GE, Dugas M, Béhanzin L, Guédou FA, Gagnon MP, Alary M, Rutakumwa R, Mbonye M, Kiwanuka T, Nakamanya S, Muhumuza R, Nalukenge W, Seeley J, Atujuna M, Wallace M, Brown B, Bekker LG, Newman PA, Harryparsad R, Olivier AJ, Jaspan HB, Wilson D, Dietrich J, Martinson N, Mukudu H, Mkhize N, Morris L, Cianci G, Dinh M, Hope T, Passmore JAS, Gray CM, Henrick BM, Yao XD, Rosenthal KL, Henrick BM, Yao XD, Drannik AG, Abimiku A, Rosenthal KL, Chanzu N, Mwanda W, Oyugi J, Anzala O, Mbow M, Jallow S, Thiam M, Davis A, Diouf A, Ndour CT, Seydi M, Dieye TN, Mboup S, Goodier M, Rilley E, Jaye A, Yao XD, Omange RW, Henrick BM, Lester RT, Kimani J, Ball TB, Plummer FA, Rosenthal KL, Béhanzin L, Guédou FA, Geraldo N, Mastétsé EG, Sossa JC, Zannou MD, Alary M, Osawe S, Okpokoro E, Okolo F, Umaru S, Abimiku R, Audu S, Datong P, Abimiku A, Nyange J, Olenja J, Mutua G, Jaoko W, Omosa-Manyonyi G, Farah B, Khaniri M, Anzala O, Cockcroft A, Tonkin K, Girish I, Mhati P, Cunningham A, Andersson N, Farah B, Indangasi J, Jaoko W, Mutua G, Khaniri M, Nyange J, Anzala O, Diphoko T, Gaseitsiwe S, Maiswe V, Iketleng T, Maruapula D, Bedi K, Moyo S, Musonda R, Wainberg M, Makhema J, Novitsky V, Marlink R, Essex M, Okoboi S, Ssali L, Kalibala S, Birungi J, Egessa A, Wangisi J, Okullu LJ, Bakanda C, Obare F, Boer IMSD, Semvua HH, van den Boogaard J, Kiwango KW, Ngowi KM, Nieuwkerk PT, Aarnoutse RE, Kiwelu I, Muro E, Kibiki GS, Datiri R, Choji G, Osawe S, Okpokoro E, Okolo F, Umaru S, Abimiku R, Audu S, Datong P, Abimiku A, Fomsgaard A, Karlsson I, Jensen KJ, Jensen SS, Leo-Hansen C, Jespersen S, Da Silva Té D, Rodrigues CM, da Silva ZJ, Janitzek CM, Gerstoft J, Kronborg G, Okpokoro E, Osawe S, Daitiri R, Choji G, Umaru S, Okolo F, Datong P, Abimiku A, Emily N, Joyce O, Robert LR, Anzala A, Viljoen K, Wendoh J, Kidzeru E, Karaoz U, Brodie E, Botha G, Mulder N, Gray C, Cameron W, Stintzi A, Jaspan H, Levett PN, Alexander D, Gulzar N, Grewal PS, Poon AFY, Brumme Z, Harrigan PR, Brooks JI, Sandstrom PA, Calvez S, Sanche SE, Scott JK, Swartz L, Kagee A, Lesch A, Kafaar Z, De Wet A, Okpokoro E, Osawe S, Daitiri R, Choji G, Umaru S, Okolo F, Datong P, Abimiku A, Dietrich J, Smith T, Cotton L, Hornschuh S, van der Watt M, Miller CL, Gray G, Smit J, Jaggernath M, Ndung’u T, Brockman M, Kaida A, Akolo M, Kimani J, Gelmon L, Chitwa M, Osero J, Cockcroft A, Marokoane N, Kgakole L, Maswabi B, Mpofu N, Ansari U, Andersson N, Nakinobe E, Miiro GM, Zalwango F, Nakiyingi-Miiro J, Kaleebu P, Semwanga JR, Nyanzi E, Musoke SN, Nakinobe E, Miiro G, Mbidde EK, Lutalo T, Kaleebu P, Handema R, Chianzu GP, Thiam M, Diagne-Gueye D, Ndiaye MK, Mbow M, Ndiaye BP, Traore I, Dia MC, Thomas G, Tour-Kane C, Mboup S, Jaye A, Nyanzi E, Mbidde EK, Kaleebu P, Mpendo J, Kimani J, Birungi J, Muyindike W, Kambugu A, Sebastian H, Ray H, Mike C, Bertin KJ, Modest M, Thiam M, Janha O, Davis A, Amambua-Ngwa A, Nwakanma DC, Mboup S, Jaye A, Jespersen S, Hønge BL, Esbjörnsson J, Medina C, Da Silva TÉ D, Correira FG, Laursen AL, Østergaard L, Andersen A, Aaby P, Erikstrup C, Wejse C, Dieye S, Sarr M, Sy H, Mbodj HD, Ndiaye M, Ndiaye A, Moussa S, Jaye A, Mboup S, Nyombi BM, Shao ER, Chilumba IB, Moyo S, Gaseitsiwe S, Musonda R, Datong P, Inyang B, Osawe S, Izang A, Cole C, Okolo F, Cameron B, Rosenthal K, Gray C, Jaspan H, Abimiku A, Seraise B, Andrea-Marobela K, Moyo S, Musonda R, Makhema J, Essex M, Gaseitsiwe S. Afri-Can Forum 2. BMC Infect Dis 2016; 16 Suppl 2:315. [PMID: 27410689 PMCID: PMC4943497 DOI: 10.1186/s12879-016-1466-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/02/2022] Open
Abstract
A1 Introduction to the 2nd synchronicity forum of GHRI/CHVI-funded Canadian and African HIV prevention and vaccine teams O1 Voluntary medical male circumcision for prevention of heterosexual transmission of HIV in adult males in Soweto: What do indicators and incidence rate show? Hillary Mukudu, Neil Martinson, Benn Sartorius O2 Developing a peer-led community mobilization program for sex workers in Soweto: HIV risk and demographics Jenny Coetzee, Janan Dietrich, Kgaugelo Mokgatswana, Rachel Jewkes, Glenda E. Gray O3 Salient beliefs about adherence: A qualitative survey conducted as part of the demonstration study on "treatment as prevention" (TasP) and "pre-exposure prophylaxis" (PrEP) among female sex workers (FSWS) in Cotonou, Benin Marylène Dugas, Luc Béhanzin, Fernand A. Guédou, Marie-Pierre Gagnon, Michel Alary O4 Relative perception of risk as a driver of unsafe sexual practices among key populations: Cases of fisherfolk and women and their partners involved in multiple sexual partnerships in Uganda Rwamahe Rutakumwa, Martin Mbonye, Thadeus Kiwanuka, Sarah Nakamanya, Richard Muhumuza, Winfred Nalukenge, Janet Seeley O5 Exploring the acceptability of new biomedical HIV prevention technologies among MSM, adolescents and heterosexual adults in South Africa Millicent Atujuna, Melissa Wallace, Ben Brown, Linda Gail Bekker, Peter A. Newman O6 HIV-susceptible target cells in foreskins after voluntary medical male circumcision in South Africa Rushil Harryparsad, Abraham J. Olivier, Heather B. Jaspan, Douglas Wilson, Janan Dietrich, Neil Martinson, Hillary Mukudu, Nonhlanhla Mkhize, Lynn Morris, Gianguido Cianci, Minh Dinh, Thomas Hope, Jo-Ann S. Passmore, Clive M. Gray O7 HIV-1 proteins activate innate immune responses via TLR2 heterodimers Bethany M. Henrick, Xiao-Dan Yao, Kenneth L. Rosenthal, the INFANT Study Team O8 Characterization of an innate factor in human milk and mechanisms of action against HIV-1 Bethany M. Henrick, Xiao-Dan Yao, Anna G. Drannik, Alash’le Abimiku, Kenneth L. Rosenthal, the INFANT Study Team O9 Secretor status and susceptibility to HIV infections among female sex workers in Nairobi, Kenya Nadia Chanzu, Walter Mwanda, Julius Oyugi, Omu Anzala O10 Natural Killer cell recall responsiveness to Gag-HIV-1 peptides of HIV-1 exposed but uninfected subjects are associated with peripheral CXCR6+ NK cell subsets Moustapha Mbow, Sabelle Jallow, Moussa Thiam, Alberta Davis, Assane Diouf, Cheikh T. Ndour, Moussa Seydi, Tandakha N. Dieye, Souleymane Mboup, Martin Goodier, Eleanor Rilley, Assan Jaye O11 Profiles of resistance: Local innate mucosal immunity to HIV-1 in commercial sex workers Xiao-Dan Yao, RW. Omange, Bethany M. Henrick, Richard T. Lester, Joshua Kimani, T. Blake Ball, Francis A. Plummer, Kenneth L. Rosenthal O12 Early antiretroviral therapy and pre-exposure prophylaxis for HIV prevention among female sex workers in Cotonou, Benin: A demonstration project Luc Béhanzin, Fernand A. Guédou, Nassirou Geraldo, Ella Goma Mastétsé, Jerôme Charles Sossa, Marcel Djimon Zannou, Michel Alary O13 Building capacity for HIV prevention trials: Preliminary data from a Nigerian cohort of HIV exposed sero-negatives (HESN) Sophia Osawe, Evaezi Okpokoro, Felicia Okolo, Stephen Umaru, Rebecca Abimiku, Sam Audu, Pam Datong, Alash’le Abimiku O14 Equipping healthcare professionals with skills required for the conduct of clinical trials in an effort to build capacity. Lessons learned Jacquelyn Nyange, Joyce Olenja, Gaudensia Mutua, Walter Jaoko, Gloria Omosa-Manyonyi, Bashir Farah, Maureen Khaniri, Omu Anzala O15 Educational technology to support active learning for HIV researchers and planners Anne Cockcroft, Kendra Tonkin, Indu Girish, Puna Mhati, Ashley Cunningham, Neil Andersson O16 From Lake Kivu (Rwanda) and Lake Malawi (Tanzania) to the shores of Lake Victoria (Uganda): Strengthening laboratory capacity through Good Clinical Laboratory Practice training Bashir Farah, Jackton Indangasi, Walter Jaoko, Gaudensia Mutua, Maureen Khaniri, Jacquelyn Nyange, Omu Anzala O17 Rilpivirine and etravirine resistance mutations in HIV-1 subtype C infected patients on a non-nucleoside reverse transcriptase inhibitor-based combination antiretroviral therapy in Botswana Thabo Diphoko, Simani Gaseitsiwe, Victoria Maiswe, Thato Iketleng, Dorcas Maruapula, Keabetswe Bedi, Sikhulile Moyo, Rosemary Musonda, Mark Wainberg, Joseph Makhema, Vladimir Novitsky, Richard Marlink, Max Essex O18 From home-based HIV testing to initiation of treatment: The AIDS Support Organization (TASO) Experience with Home-based HIV Counselling and Testing (HBHCT) among Adolescents in Uganda, 2005-2011 Stephen Okoboi, Livingstone Ssali, Sam Kalibala, Josephine Birungi, Aggrey Egessa, Jonathan Wangisi, Lyavala Joanne Okullu, Celestin Bakanda, Francis Obare41 O19 Feasibility study on using real time medication monitoring among HIV infected and Tuberculosis patients in Kilimanjaro, Tanzania I. Marion Sumari-de Boer, Hadija H. Semvua, Jossy van den Boogaard, Krisanta W. Kiwango, Kennedy M. Ngowi, Pythia T. Nieuwkerk, Rob E. Aarnoutse, Ireen Kiwelu, Eva Muro, Gibson S. Kibiki O20 Deaths still among sero-discordant cohort in Nigeria despite Access to treatment Ruth Datiri, Grace Choji, Sophia Osawe, Evaezi Okpokoro, Felicia Okolo, Stephen Umaru, Rebecca Abimiku, Samuel Audu, Pam Datong, Alash’le Abimiku O21 Therapeutic HIV-1 vaccine trials in Denmark and Guinea-Bissau Fomsgaard A, Karlsson I, Jensen KJ, Jensen SS, Leo-Hansen C, Jespersen S, Da Silva Té D, Rodrigues CM, da Silva ZJ, Janitzek CM, Gerstoft J, Kronborg G, the WAPHIR Group O22 Willingness to participate in a HIV vaccine Trial among HIV exposed sero-negative (HESN) persons in Jos, Nigeria Evaezi Okpokoro, Sophia Osawe, Ruth Daitiri, Grace Choji, Stephen Umaru, Felicia Okolo, Pam Datong, Alash'le Abimiku O23 Clinical research volunteers’ perceptions and experiences of screening for enrolment at KAVI-Institute of Clinical Research, Kenya Nyariki Emily, Olenja Joyce, Lorway R. Robert, Anzala Anzala O24 Gut microbiome, HIV-exposure, and vaccine responses in South African infants Katie Viljoen, Jerome Wendoh, Elvis Kidzeru, Ulas Karaoz, Eoin Brodie, Gerrit Botha, Nicola Mulder, Clive Gray, William Cameron, Alain Stintzi, Heather Jaspan, for the INFANT study team O25 Analysis of HIV pol diversity in the concentrated HIV epidemic in Saskatchewan Paul N. Levett, David Alexander, Naveed Gulzar, Prabvir S. Grewal, Art F. Y. Poon, Zabrina Brumme, P. Richard Harrigan, James I. Brooks, Paul A. Sandstrom, Stryker Calvez, Stephen E. Sanche, Jamie K. Scott P1 Evaluating a HIV vaccine research community engagement programme at two HIV prevention research centres in the Western Cape Leslie Swartz, Ashraf Kagee, Anthea Lesch, Zuhayr Kafaar, Anneliese De Wet P2 Validating HIV acquisition risk score using a cohort HIV exposed sero-negative persons in a discordant relationship in Jos, Nigeria, West Africa Evaezi Okpokoro, Sophia Osawe, Ruth Daitiri, Grace Choji, Stephen Umaru, Felicia Okolo, Pam Datong, Alash'le Abimiku P3 Bridging the gap between adults and adolescents and youth adults (AYA) – Employing a youth-centred approach to investigate HIV risk among AYA in Soweto and Durban, South Africa Janan Dietrich, Tricia Smith, Laura Cotton, Stefanie Hornschuh, Martin van der Watt, Cari L. Miller, Glenda Gray, Jenni Smit, Manjeetha Jaggernath, Thumbi Ndung’u, Mark Brockman, Angela Kaida, on behalf of the AYAZAZI study teams P4 Neighbours to sex workers: A key population that has been ignored Maureen Akolo, Joshua Kimani, Prof Larry Gelmon, Michael Chitwa, Justus Osero P5 Young women’s access to structural support programmes in a district of Botswana Anne Cockcroft, Nobantu Marokoane, Leagajang Kgakole, Boikhutso Maswabi, Neo Mpofu, Umaira Ansari, Neil Andersson P6 Voices for action from peri-urban Ugandan students, teachers and parents on HIV/STI prevention: Qualitative research results Nakinobe Elizabeth, Miiro George Mukalazi, Zalwango Flavia, Nakiyingi-Miiro Jessica, Kaleebu Potiano P7 Engaging Social Media as an education tool on the fly: The use of Facebook for HIV and Ebola prevention and awareness amongst adolescents in Uganda John Ross Semwanga, Emily Nyanzi, Saidat Namuli Musoke, Elizabeth Nakinobe, George Miiro, Edward Katongole Mbidde, Tom Lutalo, Pontiano Kaleebu P8 Circulating HIV-1 subtypes among sexual minority populations in Zambia Ray Handema, Graham P. Chianzu P9 The Development of HIV Bio-bank resource management to support clinical trial and Intervention research: WAPHIR experience Moussa Thiam, Diabou Diagne-Gueye, Mame K. Ndiaye, Moustapha Mbow, Birahim P. Ndiaye, Ibrahima Traore, Mamadou C. Dia, Gilleh Thomas, Coumba Tour-Kane, Souleymane Mboup, Assan Jaye P10 Capacity building for clinical trials as a novel approach for scaling up HIV prevention research initiatives in East Africa: achievements and challenges Emily Nyanzi, Edward Katongole Mbidde, Pontiano Kaleebu, Juliet Mpendo, Joshua Kimani, Josephine Birungi, Winnie Muyindike, Andrew Kambugu P11 Community and media perspective of research; an advocacy workshop on HIV prevention research Hachizovu Sebastian, Handema Ray, Chaponda Mike, Kabuya Jean Bertin, Mulenga Modest P12 Development of a quantitative HIV-1 and HIV-2 real time PCR (qRT-PCR) viral load assay Moussa Thiam, Omar Janha, Alberta Davis, Alfred Amambua-Ngwa, Davis C. Nwakanma, Souleymane Mboup, Assan Jaye P13 Differential effects of sex in a West African Cohort of HIV-1, HIV-2 and HIV-1/2 dual infected patients: Men are worse off Sanne Jespersen, Bo Langhoff Hønge, Joakim Esbjörnsson, Candida Medina, David Da Silva TÉ, Faustino Gomes Correira, Alex Lund Laursen, Lars Østergaard, Andreas Andersen, Peter Aaby, Christian Erikstrup, Christian Wejse, for the Bissau HIV Cohort study group P14 HIV-infected adolescents in transition from pediatric to adult HIV care in Dakar, Senegal: sample characteristics and immunological and virological profiles Siry Dieye, Moussa Sarr, Haby Sy, Helene D Mbodj, Marianne Ndiaye, Amy Ndiaye, Seydi Moussa, Assan Jaye, Souleymane Mboup100 P15 Molecular characterization of vertically transmitted HIV-1 among children born to HIV-1 seropositive mothers in Northern Tanzania Balthazar M. Nyombi, Elichilia R. Shao, Innocent B. Chilumba, Sikhulile Moyo, Simani Gaseitsiwe, Rosemary Musonda P16 Breast-fed HIV-1 exposed infants play catch up. A preliminary report Pam Datong, Bucky Inyang, Sophia Osawe, Abel Izang, Chundung Cole, Felicia Okolo, Bill Cameron, Kenneth Rosenthal, Clive Gray, Heather Jaspan, Alash’le Abimiku, the INFANT study team P17 The frequency of N348I mutation in patient failing combination antiretroviral treatment In Botswana Boitumelo Seraise, Kerstin Andrea-Marobela, Sikhulile Moyo, Rosemary Musonda, Joseph Makhema, Max Essex, Simani Gaseitsiwe
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Oriero EC, Van Geertruyden JP, Nwakanma DC, D'Alessandro U, Jacobs J. Novel techniques and future directions in molecular diagnosis of malaria in resource-limited settings. Expert Rev Mol Diagn 2015; 15:1419-26. [PMID: 26413727 DOI: 10.1586/14737159.2015.1090878] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Despite being preventable and treatable, malaria remains a global health concern with approximately 1.2 billion people at high risk of being infected, 90% of whom are in the resource-limited settings of sub-Saharan Africa. The continued decline in malaria cases globally has rekindled the possibility of elimination in certain regions. As humans constitute the main reservoir of malaria, prompt and accurate diagnosis by microscopy or rapid diagnostic tests is part not only of effective disease management but also of control measures. However, for malaria elimination, more sensitive diagnostic tools are needed to detect asymptomatic and sub-microscopic infections that contribute to transmission. Molecular techniques, which involve amplification of nucleic acids, are being developed and modified to suit this purpose. This report provides a summary of the nucleic acid amplification tests that are currently available for diagnosis of malaria, with current improvements and adaptations for use in resource-limited settings.
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Affiliation(s)
- Eniyou Cheryll Oriero
- a 1 Medical Research Council Unit , Fajara, The Gambia.,b 2 International Health Unit, University of Antwerp , Antwerp, Belgium.,c 3 Institute of Tropical Medicine , Antwerp, Belgium
| | | | | | - Umberto D'Alessandro
- a 1 Medical Research Council Unit , Fajara, The Gambia.,c 3 Institute of Tropical Medicine , Antwerp, Belgium.,d 4 London School of Tropical Medicine and Hygiene , London, UK
| | - Jan Jacobs
- c 3 Institute of Tropical Medicine , Antwerp, Belgium.,e 5 Department of Microbiology and Immunology, University of Leuven , Leuven, Belgium
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Santolamazza F, Caputo B, Nwakanma DC, Fanello C, Petrarca V, Conway DJ, Weetman D, Pinto J, Mancini E, della Torre A. Remarkable diversity of intron-1 of the para voltage-gated sodium channel gene in an Anopheles gambiae/Anopheles coluzzii hybrid zone. Malar J 2015; 14:9. [PMID: 25604888 PMCID: PMC4308935 DOI: 10.1186/s12936-014-0522-1] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2014] [Accepted: 12/20/2014] [Indexed: 11/26/2022] Open
Abstract
Background Genomic differentiation between Anopheles gambiae and Anopheles coluzzii - the major malaria vectors in sub-Saharan Africa - is localized into large “islands” toward the centromeres of chromosome-X and the two autosomes. Linkage disequilibrium between these genomic islands was first detected between species-specific polymorphisms within ribosomal DNA genes (IGS-rDNA) on the X-chromosome and a single variant at position 702 of intron 1 (Int-1702) of the para Voltage-Gated Sodium Channel (VGSC) gene on chromosome arm 2 L. Intron-1 sequence data from West and Central Africa revealed two clearly distinct and species-specific haplogroups, each characterized by very low polymorphism, which has been attributed to a selective sweep. The aim of this study was to analyse Int-1 sequence diversity in A. gambiae and A. coluzzii populations from the Far-West of their range, in order to assess whether this selective-sweep signature could persist in a zone of high interspecific hybridization. Methods A 531 bp region of VGSC Int-1 was sequenced in 21 A. coluzzii, 31 A. gambiae, and 12 hybrids from The Gambia and Guinea Bissau, located within the Far-West geographical region, and in 53 A. gambiae s.l. samples from the rest of the range. Results Far-West samples exhibit dramatic Int-1 polymorphism, far higher within each country than observed throughout the rest of the species range. Moreover, patterning of haplotypes within A. coluzzii confirms previous evidence of a macro-geographic subdivision into a West and a Central African genetic cluster, and reveals a possible genetic distinction of A. coluzzii populations from the Far-West. Conclusions The results suggest a relaxation of selective pressures acting across the VGSC gene region in the hybrid zone. Genetic differentiation in the Far-West could be attributable to a founder effect within A. coluzzii, with subsequent extensive gene flow with secondarily-colonizing A. gambiae, potentially yielding a novel insight on the dynamic processes impacting genetic divergence of these key malaria vectors. Electronic supplementary material The online version of this article (doi:10.1186/s12936-014-0522-1) contains supplementary material, which is available to authorized users.
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Affiliation(s)
| | | | | | | | | | | | | | | | - Emiliano Mancini
- Dipartimento di Sanità Pubblica e Malattie Infettive, Istituto Pasteur-Fondazione Cenci-Bolognetti, Università "Sapienza", Piazzale Aldo Moro 5, Rome, 00185, Italy.
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Oyebola MK, Idowu ET, Nyang H, Olukosi YA, Otubanjo OA, Nwakanma DC, Awolola ST, Amambua-Ngwa A. Microsatellite markers reveal low levels of population sub-structuring of Plasmodium falciparum in southwestern Nigeria. Malar J 2014; 13:493. [PMID: 25496185 PMCID: PMC4300683 DOI: 10.1186/1475-2875-13-493] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2014] [Accepted: 12/09/2014] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Genetic diversity studies provide evidence of Plasmodium falciparum differentiation that could affect fitness and adaptation to drugs and target antigens for vaccine development. This study describes the genetic structure of P. falciparum populations in urban and rural sites from southwestern Nigeria. METHODOLOGY Ten neutral microsatellite loci were genotyped in 196 P. falciparum infections from three localities: Aramoko-Ekiti, a rural community; Lekki, an urban location and Badagry, a peri-urban border settlement. Analysis was performed on the genetic diversity, linkage disequilibrium, population structure and inter-population differentiation. RESULTS Allelic diversity values were similar across all populations, with mean expected heterozygosity (HE) values between 0.65 and 0.79. No matching multilocus haplotypes were found and analysis of multilocus LD showed no significant index of association. Genetic differentiation between populations was low (ΦPT = 0.017). CONCLUSION The absence of detectable population structure of P. falciparum in southwestern Nigeria is evident in the lack of significant differentiation between populations separated by about 200 km. This implies that a fairly uniform malaria control strategy may be effective over a wide geographic range in this highly endemic region. However, more wide-scale survey across the country will be required to inform malaria control in this large and densely populated endemic region.
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Mobegi VA, Duffy CW, Amambua-Ngwa A, Loua KM, Laman E, Nwakanma DC, MacInnis B, Aspeling-Jones H, Murray L, Clark TG, Kwiatkowski DP, Conway DJ. Genome-wide analysis of selection on the malaria parasite Plasmodium falciparum in West African populations of differing infection endemicity. Mol Biol Evol 2014; 31:1490-9. [PMID: 24644299 PMCID: PMC4032133 DOI: 10.1093/molbev/msu106] [Citation(s) in RCA: 85] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Locally varying selection on pathogens may be due to differences in drug pressure, host immunity, transmission opportunities between hosts, or the intensity of between-genotype competition within hosts. Highly recombining populations of the human malaria parasite Plasmodium falciparum throughout West Africa are closely related, as gene flow is relatively unrestricted in this endemic region, but markedly varying ecology and transmission intensity should cause distinct local selective pressures. Genome-wide analysis of sequence variation was undertaken on a sample of 100 P. falciparum clinical isolates from a highly endemic region of the Republic of Guinea where transmission occurs for most of each year and compared with data from 52 clinical isolates from a previously sampled population from The Gambia, where there is relatively limited seasonal malaria transmission. Paired-end short-read sequences were mapped against the 3D7 P. falciparum reference genome sequence, and data on 136,144 single nucleotide polymorphisms (SNPs) were obtained. Within-population analyses identifying loci showing evidence of recent positive directional selection and balancing selection confirm that antimalarial drugs and host immunity have been major selective agents. Many of the signatures of recent directional selection reflected by standardized integrated haplotype scores were population specific, including differences at drug resistance loci due to historically different antimalarial use between the countries. In contrast, both populations showed a similar set of loci likely to be under balancing selection as indicated by very high Tajima’s D values, including a significant overrepresentation of genes expressed at the merozoite stage that invades erythrocytes and several previously validated targets of acquired immunity. Between-population FST analysis identified exceptional differentiation of allele frequencies at a small number of loci, most markedly for five SNPs covering a 15-kb region within and flanking the gdv1 gene that regulates the early stages of gametocyte development, which is likely related to the extreme differences in mosquito vector abundance and seasonality that determine the transmission opportunities for the sexual stage of the parasite.
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Affiliation(s)
- Victor A Mobegi
- Pathogen Molecular Biology Department, London School of Hygiene and Tropical Medicine, London, United KingdomMedical Research Council Unit, Fajara, Banjul, The Gambia
| | - Craig W Duffy
- Pathogen Molecular Biology Department, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | | | - Kovana M Loua
- National Institute of Public Health, Conakry, Republic of Guinea
| | - Eugene Laman
- National Institute of Public Health, Conakry, Republic of Guinea
| | | | - Bronwyn MacInnis
- The Wellcome Trust Sanger Institute, Hinxton, Cambridge, United Kingdom
| | - Harvey Aspeling-Jones
- Pathogen Molecular Biology Department, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Lee Murray
- Pathogen Molecular Biology Department, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Taane G Clark
- Pathogen Molecular Biology Department, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Dominic P Kwiatkowski
- The Wellcome Trust Sanger Institute, Hinxton, Cambridge, United KingdomWellcome Trust Centre for Human Genetics, University of Oxford, Oxford, United Kingdom
| | - David J Conway
- Pathogen Molecular Biology Department, London School of Hygiene and Tropical Medicine, London, United KingdomMedical Research Council Unit, Fajara, Banjul, The Gambia
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Nwakanma DC, Duffy CW, Amambua-Ngwa A, Oriero EC, Bojang KA, Pinder M, Drakeley CJ, Sutherland CJ, Milligan PJ, Macinnis B, Kwiatkowski DP, Clark TG, Greenwood BM, Conway DJ. Changes in malaria parasite drug resistance in an endemic population over a 25-year period with resulting genomic evidence of selection. J Infect Dis 2013; 209:1126-35. [PMID: 24265439 PMCID: PMC3952670 DOI: 10.1093/infdis/jit618] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Background. Analysis of genome-wide polymorphism in many organisms has potential to identify genes under recent selection. However, data on historical allele frequency changes are rarely available for direct confirmation. Methods. We genotyped single nucleotide polymorphisms (SNPs) in 4 Plasmodium falciparum drug resistance genes in 668 archived parasite-positive blood samples of a Gambian population between 1984 and 2008. This covered a period before antimalarial resistance was detected locally, through subsequent failure of multiple drugs until introduction of artemisinin combination therapy. We separately performed genome-wide sequence analysis of 52 clinical isolates from 2008 to prospect for loci under recent directional selection. Results. Resistance alleles increased from very low frequencies, peaking in 2000 for chloroquine resistance-associated crt and mdr1 genes and at the end of the survey period for dhfr and dhps genes respectively associated with pyrimethamine and sulfadoxine resistance. Temporal changes fit a model incorporating likely selection coefficients over the period. Three of the drug resistance loci were in the top 4 regions under strong selection implicated by the genome-wide analysis. Conclusions. Genome-wide polymorphism analysis of an endemic population sample robustly identifies loci with detailed documentation of recent selection, demonstrating power to prospectively detect emerging drug resistance genes.
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Thézénas ML, Huang H, Njie M, Ramaprasad A, Nwakanma DC, Fischer R, Digleria K, Walther M, Conway DJ, Kessler BM, Casals-Pascual C. PfHPRT: A New Biomarker Candidate of Acute Plasmodium falciparum Infection. J Proteome Res 2013; 12:1211-22. [DOI: 10.1021/pr300858g] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Marie L. Thézénas
- Wellcome Trust Centre for Human
Genetics and Henry Wellcome Building for Molecular Physiology, Nuffield
Department of Medicine, University of Oxford, Oxford OX3 7BN, U. K
| | - Honglei Huang
- Wellcome Trust Centre for Human
Genetics and Henry Wellcome Building for Molecular Physiology, Nuffield
Department of Medicine, University of Oxford, Oxford OX3 7BN, U. K
| | - Madi Njie
- Malaria Programme, MRC Unit, Banjul, The
Gambia
| | - Abhinay Ramaprasad
- Wellcome Trust Centre for Human
Genetics and Henry Wellcome Building for Molecular Physiology, Nuffield
Department of Medicine, University of Oxford, Oxford OX3 7BN, U. K
- King Abdulla University of Science and Technology, Saudi Arabia
| | | | - Roman Fischer
- Wellcome Trust Centre for Human
Genetics and Henry Wellcome Building for Molecular Physiology, Nuffield
Department of Medicine, University of Oxford, Oxford OX3 7BN, U. K
| | - Katalin Digleria
- Weatherall Institute of Molecular
Medicine, Nuffield Department of Medicine, University of Oxford, Oxford, U. K
| | - Michael Walther
- National Institutes of Health, National Institute of Allergy and Infectious
Diseases, Rockville, Maryland, United States
| | - David J. Conway
- London School of Hygiene and Tropical Medicine, London, U. K
| | - Benedikt M. Kessler
- Wellcome Trust Centre for Human
Genetics and Henry Wellcome Building for Molecular Physiology, Nuffield
Department of Medicine, University of Oxford, Oxford OX3 7BN, U. K
| | - Climent Casals-Pascual
- Wellcome Trust Centre for Human
Genetics and Henry Wellcome Building for Molecular Physiology, Nuffield
Department of Medicine, University of Oxford, Oxford OX3 7BN, U. K
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Mobegi VA, Loua KM, Ahouidi AD, Satoguina J, Nwakanma DC, Amambua-Ngwa A, Conway DJ. Population genetic structure of Plasmodium falciparum across a region of diverse endemicity in West Africa. Malar J 2012; 11:223. [PMID: 22759447 PMCID: PMC3425276 DOI: 10.1186/1475-2875-11-223] [Citation(s) in RCA: 82] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2012] [Accepted: 07/03/2012] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Malaria parasite population genetic structure varies among areas of differing endemicity, but this has not been systematically studied across Plasmodium falciparum populations in Africa where most infections occur. METHODS Ten polymorphic P. falciparum microsatellite loci were genotyped in 268 infections from eight locations in four West African countries (Republic of Guinea, Guinea Bissau, The Gambia and Senegal), spanning a highly endemic forested region in the south to a low endemic Sahelian region in the north. Analysis was performed on proportions of mixed genotype infections, genotypic diversity among isolates, multilocus standardized index of association, and inter-population differentiation. RESULTS Each location had similar levels of pairwise genotypic diversity among isolates, although there were many more mixed parasite genotype infections in the south. Apart from a few isolates that were virtually identical, the multilocus index of association was not significant in any population. Genetic differentiation between populations was low (most pairwise F(ST) values < 0.03), and an overall test for isolation by distance was not significant. CONCLUSIONS Although proportions of mixed genotype infections varied with endemicity as expected, population genetic structure was similar across the diverse sites. Very substantial reduction in transmission would be needed to cause fragmented or epidemic sub-structure in this region.
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Affiliation(s)
- Victor A Mobegi
- Department of Pathogen Molecular Biology, London School of Hygiene and Tropical Medicine, UK
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Estévez PT, Satoguina J, Nwakanma DC, West S, Conway DJ, Drakeley CJ. Human saliva as a source of anti-malarial antibodies to examine population exposure to Plasmodium falciparum. Malar J 2011; 10:104. [PMID: 21527045 PMCID: PMC3112448 DOI: 10.1186/1475-2875-10-104] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2011] [Accepted: 04/29/2011] [Indexed: 11/17/2022] Open
Abstract
Background Antibody responses to malaria antigens reflect exposure to parasites, and seroprevalence correlates with malaria transmission intensity. Antibodies are routinely measured in sera or on dried blood spots but a non-invasive method would provide extra utility in sampling general populations. Saliva is already in use in the detection of plasma-derived IgM and IgG to viral infections. In this study, antibodies to Plasmodium falciparum merozoite antigens were compared between blood and saliva samples from the same individuals in unlinked surveys conducted in Tanzania and The Gambia. Methods In Tanzania, 53 individuals provided paired fingerprick blood and saliva sample using two commercially available sampling devices. In the Gambia, archived plasma and saliva samples collected from 200 children in the Farafenni area in a cross-sectional survey were analyzed. IgG antibodies against P. falciparum antigens, Merozoite Surface Protein-1 (MSP-119) and Apical membrane Antigen (AMA-1) were measured by ELISA in paired saliva and blood samples from both sites. Antibody levels were compared as continuous optical density (OD) values and by sero-positivity. Results Significant correlations between saliva and plasma antibody levels were seen in Tanzania for both antigens, AMA-1(r2 range 0.93 to 0.89, p < 0.001) and MSP-119 (r2 range 0.93 to 0.75, p < 0.001), with a weaker correlation for results from The Gambia (r2range 0.64 to 0.63, p < 0.01). When assessed as seropositivity and compared with plasma, sensitivity and specificity were good with saliva antibody levels to both AMA-1 and MSP-119 (sensitivity range 64-77% and specificity range 91-100% & 47-67% and 90-97% respectively) over the different sample sets. Conclusions These data demonstrate anti-malarial antibodies can be detected in saliva and correlate strongly with levels in plasma. This non-invasive relatively simple collection method will be potentially useful for general population surveys, and particularly in migratory populations or those with infrequent contact with health services or opposed to blood withdrawal. Further studies will be needed to optimize collection methods, standardize volumes and content and develop controls.
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Caputo B, Santolamazza F, Vicente JL, Nwakanma DC, Jawara M, Palsson K, Jaenson T, White BJ, Mancini E, Petrarca V, Conway DJ, Besansky NJ, Pinto J, Torre AD. The "far-west" of Anopheles gambiae molecular forms. PLoS One 2011; 6:e16415. [PMID: 21347223 PMCID: PMC3039643 DOI: 10.1371/journal.pone.0016415] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2010] [Accepted: 12/15/2010] [Indexed: 11/18/2022] Open
Abstract
The main Afrotropical malaria vector, Anopheles gambiae sensu stricto, is undergoing a process of sympatric ecological diversification leading to at least two incipient species (the M and S molecular forms) showing heterogeneous levels of divergence across the genome. The physically unlinked centromeric regions on all three chromosomes of these closely related taxa contain fixed nucleotide differences which have been found in nearly complete linkage disequilibrium in geographic areas of no or low M-S hybridization. Assays diagnostic for SNP and structural differences between M and S forms in the three centromeric regions were applied in samples from the western extreme of their range of sympatry, the only area where high frequencies of putative M/S hybrids have been reported. The results reveal a level of admixture not observed in the rest of the range. In particular, we found: i) heterozygous genotypes at each marker, although at frequencies lower than expected under panmixia; ii) virtually all possible genotypic combinations between markers on different chromosomes, although genetic association was nevertheless detected; iii) discordant M and S genotypes at two X-linked markers near the centromere, suggestive of introgression and inter-locus recombination. These results could be indicative either of a secondary contact zone between M and S, or of the maintenance of ancestral polymorphisms. This issue and the perspectives opened by these results in the study of the M and S incipient speciation process are discussed.
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Affiliation(s)
- Beniamino Caputo
- Istituto Pasteur-Fondazione Cenci-Bolognetti, Dipartimento di Sanità Pubblica e Malattie Infettive, Università di Roma “Sapienza”, Rome, Italy
| | - Federica Santolamazza
- Istituto Pasteur-Fondazione Cenci-Bolognetti, Dipartimento di Sanità Pubblica e Malattie Infettive, Università di Roma “Sapienza”, Rome, Italy
| | - José L. Vicente
- Centro de Malária e outras Doenças Tropicais, UEI Malária and UEI Entomologia Médica, Instituto de Higiene e Medicina Tropical, Universidade Nova de Lisboa, Lisbon, Portugal
| | | | - Musa Jawara
- Medical Research Council Laboratories, Banjul, The Gambia
| | - Katinka Palsson
- Medical Entomology Unit, Department of Systematic Biology, Uppsala University, Uppsala, Sweden
| | - Thomas Jaenson
- Medical Entomology Unit, Department of Systematic Biology, Uppsala University, Uppsala, Sweden
| | - Bradley J. White
- Eck Institute for Global Health, Department of Biological Sciences, University of Notre Dame, Notre Dame, Indiana, United States of America
| | - Emiliano Mancini
- Istituto Pasteur-Fondazione Cenci-Bolognetti, Dipartimento di Sanità Pubblica e Malattie Infettive, Università di Roma “Sapienza”, Rome, Italy
| | - Vincenzo Petrarca
- Istituto Pasteur-Fondazione Cenci-Bolognetti, Dipartimento di Biologia e Biotecnologie “Charles Darwin”, Università di Roma “Sapienza”, Rome, Italy
| | | | - Nora J. Besansky
- Eck Institute for Global Health, Department of Biological Sciences, University of Notre Dame, Notre Dame, Indiana, United States of America
| | - João Pinto
- Centro de Malária e outras Doenças Tropicais, UEI Malária and UEI Entomologia Médica, Instituto de Higiene e Medicina Tropical, Universidade Nova de Lisboa, Lisbon, Portugal
| | - Alessandra della Torre
- Istituto Pasteur-Fondazione Cenci-Bolognetti, Dipartimento di Sanità Pubblica e Malattie Infettive, Università di Roma “Sapienza”, Rome, Italy
- * E-mail:
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Ceesay SJ, Casals-Pascual C, Nwakanma DC, Walther M, Gomez-Escobar N, Fulford AJC, Takem EN, Nogaro S, Bojang KA, Corrah T, Jaye MC, Taal MA, Sonko AAJ, Conway DJ. Continued decline of malaria in The Gambia with implications for elimination. PLoS One 2010; 5:e12242. [PMID: 20805878 PMCID: PMC2923605 DOI: 10.1371/journal.pone.0012242] [Citation(s) in RCA: 114] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2010] [Accepted: 07/03/2010] [Indexed: 11/18/2022] Open
Abstract
Background A substantial decline in malaria was reported to have occurred over several years until 2007 in the western part of The Gambia, encouraging consideration of future elimination in this previously highly endemic region. Scale up of interventions has since increased with support from the Global Fund and other donors. Methodology/Principal Findings We continued to examine laboratory records at four health facilities previously studied and investigated six additional facilities for a 7 year period, adding data from 243,707 slide examinations, to determine trends throughout the country until the end of 2009. We actively detected infections in a community cohort of 800 children living in rural villages throughout the 2008 malaria season, and assayed serological changes in another rural population between 2006 and 2009. Proportions of malaria positive slides declined significantly at all of the 10 health facilities between 2003 (annual mean across all sites, 38.7%) and 2009 (annual mean, 7.9%). Statistical modelling of trends confirmed significant seasonality and decline over time at each facility. Slide positivity was lowest in 2009 at all sites, except two where lowest levels were observed in 2006. Mapping households of cases presenting at the latter sites in 2007–2009 indicated that these were not restricted to a few residual foci. Only 2.8% (22/800) of a rural cohort of children had a malaria episode in the 2008 season, and there was substantial serological decline between 2006 and 2009 in a separate rural area. Conclusions Malaria has continued to decline in The Gambia, as indicated by a downward trend in slide positivity at health facilities, and unprecedented low incidence and seroprevalence in community surveys. We recommend intensification of control interventions for several years to further reduce incidence, prior to considering an elimination programme.
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Affiliation(s)
- Serign J. Ceesay
- Medical Research Council Laboratories, Fajara, Banjul, The Gambia
| | - Climent Casals-Pascual
- Medical Research Council Laboratories, Fajara, Banjul, The Gambia
- Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford, United Kingdom
| | | | - Michael Walther
- Medical Research Council Laboratories, Fajara, Banjul, The Gambia
| | | | - Anthony J. C. Fulford
- Medical Research Council Laboratories, Fajara, Banjul, The Gambia
- Department of Infectious & Tropical Diseases, London School of Hygiene & Tropical Medicine, London, United Kingdom
| | - Ebako N. Takem
- Medical Research Council Laboratories, Fajara, Banjul, The Gambia
| | - Sarah Nogaro
- Medical Research Council Laboratories, Fajara, Banjul, The Gambia
| | - Kalifa A. Bojang
- Medical Research Council Laboratories, Fajara, Banjul, The Gambia
| | - Tumani Corrah
- Medical Research Council Laboratories, Fajara, Banjul, The Gambia
| | - Momodou Cherno Jaye
- National Health Laboratory Services, Royal Victoria Teaching Hospital, Banjul, The Gambia
| | | | | | - David J. Conway
- Medical Research Council Laboratories, Fajara, Banjul, The Gambia
- Department of Infectious & Tropical Diseases, London School of Hygiene & Tropical Medicine, London, United Kingdom
- * E-mail:
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Jawara M, Smallegange RC, Jeffries D, Nwakanma DC, Awolola TS, Knols BGJ, Takken W, Conway DJ. Optimizing odor-baited trap methods for collecting mosquitoes during the malaria season in The Gambia. PLoS One 2009; 4:e8167. [PMID: 19997640 PMCID: PMC2780730 DOI: 10.1371/journal.pone.0008167] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2009] [Accepted: 10/21/2009] [Indexed: 11/18/2022] Open
Abstract
Background Baited traps are potential tools for removal or surveillance of disease vectors. To optimize the use of counter-flow traps baited with human odor (nylon socks that had been worn for a single day) to capture wild mosquitoes in the Gambia, investigations were conducted at a field experimental site. Methodology/Principal Findings Experiments employing Latin square design were conducted with a set of six huts to investigate the effects of the following on overnight mosquito trap catches: (1) placement of traps indoors or immediately outdoors, CO2 supply, and presence of a human subject in the hut; (2) trap height for collecting mosquitoes immediately outdoors; (3) height and distance from hut; (4) interaction between multiple traps around a single hut and entry of mosquitoes into huts. A total of 106,600 adult mosquitoes (9.1% Anopheles gambiae s.l., 4.0% other Anopheles species) were collected over 42 nights. The high numbers of An. gambiae s.l. and other mosquitoes collected by odor-baited traps required CO2 but were largely independent of the presence of a person sleeping in the hut or of trap placement indoors or outdoors. For outdoor collection that is considered less intrusive, traps opening 15 cm above the floor of the hut veranda were more highly effective than traps at other heights or further from the hut. There was no significant evidence of saturation or competition by the traps, with multiple traps around a hut each collecting almost as many mosquitoes as single traps and no effect on the numbers of mosquitoes entering the huts. Conclusions/Significance The outdoor trapping protocol is convenient to compare attractiveness of different odors or synthetic chemicals to malaria vectors and other wild mosquitoes. The finding that such traps are reliably attractive in the presence or absence of a human volunteer encourages their potential development as standardised surveillance tools.
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Affiliation(s)
- Musa Jawara
- Medical Research Council Laboratories, Fajara, Banjul, The Gambia
| | | | - David Jeffries
- Medical Research Council Laboratories, Fajara, Banjul, The Gambia
| | | | | | - Bart G. J. Knols
- Laboratory of Entomology, Wageningen University, Wageningen, The Netherlands
| | - Willem Takken
- Laboratory of Entomology, Wageningen University, Wageningen, The Netherlands
| | - David J. Conway
- Medical Research Council Laboratories, Fajara, Banjul, The Gambia
- * E-mail:
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Nwakanma DC, Gomez-Escobar N, Walther M, Crozier S, Dubovsky F, Malkin E, Locke E, Conway DJ. Quantitative detection of Plasmodium falciparum DNA in saliva, blood, and urine. J Infect Dis 2009; 199:1567-74. [PMID: 19432544 DOI: 10.1086/598856] [Citation(s) in RCA: 74] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022] Open
Abstract
BACKGROUND Current methods for detecting malaria parasites are invasive and associated with poor compliance when repeated sampling is required. New methods to detect and quantify parasites in a less-invasive manner would greatly enhance the potential for longitudinal surveillance in clinical trials. METHODS Saliva, urine, and blood samples from 386 Gambian outpatients with suspected malaria infections were analyzed by nested polymerase chain reaction (nPCR) to detect infection and to evaluate diagnostic accuracy in comparison to expert microscopy. The amount of parasite DNA in malaria-positive samples was estimated using real-time quantitative PCR (qPCR). RESULTS Blood parasite density as estimated by qPCR correlated well with parasite counts established by microscopy (p = 0.94; P < .001). qPCR results for saliva had a significant correlation with microscopy counts (p = 0.58; P < .001), whereas qPCR results for urine had a positive but poor correlation with microscopy counts (p = 0.20; P = .117). The mean amounts of parasite DNA quantified in blood were greater than the mean amounts quantified in saliva and urine samples obtained concurrently from the same individual, by approximately 600-fold and approximately 2500-fold, respectively. When nPCR results were compared with microscopy results, nPCR of saliva had a sensitivity of 73% and a specificity of 97%; its sensitivity increased to 82% in samples with a parasite density of > or = 1000 parasites/microL. nPCR of urine had a sensitivity of 32% and a specificity of 98%. CONCLUSION Saliva sampling is a promising less-invasive approach for detecting malaria infection.
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Affiliation(s)
- Davis C Nwakanma
- Medical Research Council (United Kingdom) Laboratories, Fajara, Banjul, The Gambia.
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16
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Jawara M, Pinder M, Drakeley CJ, Nwakanma DC, Jallow E, Bogh C, Lindsay SW, Conway DJ. Dry season ecology of Anopheles gambiae complex mosquitoes in The Gambia. Malar J 2008; 7:156. [PMID: 18710559 PMCID: PMC2533673 DOI: 10.1186/1475-2875-7-156] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2008] [Accepted: 08/18/2008] [Indexed: 11/10/2022] Open
Abstract
Background Malaria in The Gambia is highly seasonal, with transmission occurring as Anopheles gambiae s.l. populations expand during and immediately after a single annual rainy season that lasts from June to October. There has been very limited investigation of the ecology of vectors during the dry season, when numbers are very limited and distributions may be restricted. Methods Weekly adult mosquito collections (pyrethrum spray, light trap, and search collections from rooms, as well as light trap collections from animal shelters, abandoned wells and grain stores), and artificial sentinel breeding site surveys were performed in four villages near the upper tidal and partially saline part of the Gambia River in the last four months of an annual dry season (March to June). Mosquito species were identified by morphological and DNA analysis, and ELISA assays were performed to test for Plasmodium falciparum sporozoites and human blood meal components. Results Adults of An. gambiae s.l. were collected throughout the period, numbers increasing towards the end of the dry season when humidity was increasing. Adult collections were dominated by An. melas (86%), with An. gambiae s.s. (10%) and An. arabiensis (3%) also present throughout. Most females collected in room search and spray collections contained blood meals, but most from light traps were unfed. None of the females tested (n = 1709) contained sporozoites. Larvae (mostly An. gambiae s.s.) were recovered from artificial sentinel breeding sites in the two villages that had freshwater pools. These two villages had the highest proportions of An. gambiae s.s. adults, and experienced the most substantial increase in proportions of An. gambiae s.s. after the onset of rains. Conclusion During the dry season population minimum, An. melas was the predominant vector species, but differences among villages in availability of fresh-water breeding sites correlate with egg laying activity and relative numbers of An. gambiae s.s. adults, and with the increase in this species immediately after the beginning of the rains. Local variation in dry season vector persistence is thus likely to influence spatial heterogeneity of transmission intensity in the early part of the rainy season.
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Affiliation(s)
- Musa Jawara
- Medical Research Council Laboratories, Fajara, PO Box 273, Banjul, The Gambia.
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Nwakanma DC, Pillay M, Okoli BE, Tenkouano A. PCR-RFLP of the ribosomal DNA internal transcribed spacers (ITS) provides markers for the A and B genomes in Musa L. Theor Appl Genet 2003; 108:154-9. [PMID: 12955208 DOI: 10.1007/s00122-003-1402-1] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/02/2003] [Accepted: 07/15/2003] [Indexed: 05/21/2023]
Abstract
Musa acuminata Colla (AA genomes) and Musa balbisiana Colla (BB genomes) are the diploid ancestors of modern bananas that are mostly diploid or triploid cultivars with various combinations of the A and B genomes, including AA, AAA, BB, AAB and ABB. The objective of this study was to identify molecular markers that will facilitate discrimination of the A and B genomes, based on restriction-site variations in the internal transcribed spacers (ITS) of the nuclear ribosomal RNA genes. The ITS regions of seven M. acuminata and five M. balbisiana accessions were each amplified by PCR using specific primers. All accessions produced a 700-bp fragment that is equivalent in size to the ITS of most plants. This fragment was then digested with ten restriction enzymes ( AluI, CfoI, DdeI, HaeIII, HinfI, HpaII, MspI, RsaI, Sau3AI and TaqI) and fractionated in 2% agarose gels, stained with ethidium bromide and visualized under UV light. The RsaI digest revealed a single 530-bp fragment unique to the A genome and two fragments of 350-bp and 180-bp that were specific to the B genome. A further 56 accessions representing AA, AAA, AAB, AB and ABB cultivars, and synthetic hybrids, were amplified and screened with RsaI. All accessions with an exclusively A genome showed only the 530-bp fragment, while accessions having only the B-genome lacked the 530-bp fragment but had the 350-bp and 180-bp fragments. Interspecific cultivars possessed all three fragments. The staining intensity of the B-genome markers increased with the number of B-genome complements. These markers can be used to determine the genome constitution of Musa accessions and hybrids at the nursery stage, and, therefore, greatly facilitate genome classification in Musa breeding.
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Affiliation(s)
- D C Nwakanma
- International Institute of Tropical Agriculture, PMB 008 Nchia-Eleme, Port Harcourt, Nigeria
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Nwakanma DC, Pillay M, Okoli BE, Tenkouano A. Sectional relationships in the genus Musa L. inferred from the PCR-RFLP of organelle DNA sequences. Theor Appl Genet 2003; 107:850-856. [PMID: 12827254 DOI: 10.1007/s00122-003-1340-y] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/10/2003] [Accepted: 04/30/2003] [Indexed: 05/24/2023]
Abstract
The objective of this study was to construct a molecular phylogeny of the genus Musa using restriction-site polymorphisms of the chloroplast (cpDNA) and mitochondrial DNA (mtDNA). Six cpDNA and two mtDNA sequences were amplified individually in polymerase chain reaction (PCR) experiments in 13 species representing the four sections of Musa. Ensete ventricosum (W.) Ch. was used as the outgroup. The amplified products were digested with ten restriction endonucleases. A total of 79 restriction-site changes were scored in the sample. Wagner parsimony using the branch and bound option defined two lines of evolution in Musa. One lineage comprised species of the sections Australimusa and Callimusa which have a basic number of x = 10 chromosomes, while most species of sections Eumusa and Rhodochlamys ( x = 11) formed the other lineage. Musa laterita Cheesman ( Rhodochlamys) had identical organellar genome patterns as some subspecies of the Musa acuminata Colla complex. The progenitors of the cultivated bananas, M. acuminata and Musa balbisiana Colla, were evolutionarily distinct from each other. Musa balbisiana occupied a basal position in the cladogram indicating an evolutionarily primitive status. The close phylogenetic relationship between M. laterita and M. acuminata suggests that species of the section Rhodochlamys may constitute a secondary genepool for the improvement of cultivated bananas.
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Affiliation(s)
- D C Nwakanma
- International Institute of Tropical Agriculture, High Rainfall Station, P.M.B. 008, Nchia-Eleme (Port-Harcourt), Rivers State, Nigeria
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Abstract
Plantains and bananas (Musa spp. sect. eumusa) originated from intra- and interspecific hybridization between two wild diploid species, M. acuminata Colla. and M. balbisiana Colla., which contributed the A and B genomes, respectively. Polyploidy and hybridization have given rise to a number of diploid, triploid, and tetraploid clones with different permutations of the A and B genomes. Thus, dessert and highland bananas are classified mainly as AAA, plantains are AAB, and cooking bananas are ABB. Classification of Musa into genomic groups has been based on morphological characteristics. This study aimed to identify RAPD (random amplified polymorphic DNA) markers for the A and B genomes. Eighty 10-mer Operon primers were used to amplify DNA from M. acuminata subsp. burmannicoides clone 'Calcutta 4' (AA genomes) and M. balbisiana clone 'Honduras' (BB genomes). Three primers (A17, A18, and D10) that produced unique genome-specific fragments in the two species were identified. These primers were tested in a sample of 40 genotypes representing various genome combinations. The RAPD markers were able to elucidate the genome composition of all the genotypes. The results showed that RAPD analysis can provide a quick and reliable system for genome identification in Musa that could facilitate genome characterization and manipulations in breeding lines.
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Affiliation(s)
- M Pillay
- Plantain and Banana Improvement Project, International Institute of Tropical Agriculture, Nchia Eleme, Rivers State, Nigeria.
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