Eranga Bandara, Xueping Liang, Sachin Shetty, Wee Keong Ng, Peter Foytik, Nalin Ranasinghe, Kasun De Zoysa, Bård Langöy, David Larsson,
... building a blockchain-based document archive storage platform, "Lekana". The Lekana platform can be adopted by service providers that ... cloud-based e-invoicing provider in Europe. With Lekana we introduce a novel approach to store an ... by the customers in the blockchain. The proposed Lekana platform is built on top of Mystiko which ... data analytics and machine learning techniques into the Lekana platform by using the Mystiko-Ml machine learning service on Mystiko blockchain. By integrating the Lekana platform with blockchain technology, we have addressed major ...
Tópico(s): Cloud Computing and Resource Management
2020 - Springer Science+Business Media | Lecture notes in computer science
Dominique Fatima Voumbo-Matoumona, Lady Charlène Kouna, Marylin Madamet, Sydney Maghendji-Nzdondo, Bruno Pradines, Jean Bernard Lékana-Douki,
... 4 Bruno Pradines,2,5,6 Jean Bernard Lekana-Douki1,4 1Unit of Evolution, Epidemiology and Parasitic ...
Tópico(s): Hepatitis B Virus Studies
2018 - Dove Medical Press | Infection and Drug Resistance
Eduan Wilkinson, Marta Giovanetti, Houriiyah Tegally, James Emmanuel San, Richard Lessells, Diego F. Cuadros, Darren P. Martin, David A. Rasmussen, Abdel‐Rahman N. Zekri, Abdoul Karim Sangaré, Abdoul–Salam Ouédraogo, Abdul Karim Sesay, Priscilla Abechi, Adedotun-Sulaiman Kemi, Adewunmi M. Olubusuyi, Oluwapelumi O. Adeyemi, Adnène Hammami, Adrienne Amuri-Aziza, Ahmad Sayed, Ahmed E. O. Ouma, Aida Elargoubi, Nnennaya Anthony Ajayi, Ajogbasile F. Victoria, Kazeem Akano, Akpede George, Alexander J. Trotter, Yahaya Ali Ahmed, Alpha Kabinet Keïta, Amadou Diallo, A. Koné, Amal Souissi, Amel Chtourou, Ana Victoria Gutiérrez, Andrew J. Page, Anika Vinzé, Arash Iranzadeh, Arnold W. Lambisia, Arshad Ismail, Rosemary Audu, Augustina Angelina Sylverken, Femi Ayoade, Azeddine Ibrahimi, Baba M, Bamidele Soji Oderinde, Bankole Bolajoko, Beatrice Dhaala, Belinda L. Herring, Berthe‐Marie Njanpop‐Lafourcade, Bronwyn Kleinhans, Bronwyn McInnis, Bryan Tegomoh, Cara E. Brook, Catherine Pratt, Cathrine Scheepers, Chantal Akoua‐Koffi, Charles N. Agoti, Christophe N. Peyrefitte, Claudia Daubenberger, Collins M. Morang’a, D. James Nokes, Daniel G. Amoako, Daniel Lule Bugembe, Daniel J. Park, David Baker, Deelan Doolabh, Deogratius Ssemwanga, Derek Tshiabuila, Bassirou Diarra, Dominic S. Y. Amuzu, Dominique Goedhals, Donwilliams O. Omuoyo, Dorcas Maruapula, Ebenezer Foster-Nyarko, Eddy Kinganda-Lusamaki, Edgar Simulundu, Edidah M. Ong’era, Edith N. Ngabana, Edwin Shumba, Elmostafa El Fahime, Emmanuel Lokilo, Enatha Mukantwari, Eromon Philomena, Essia Belarbi, Etienne Simon‐Lorière, Etilé A. Anoh, Fabian H. Leendertz, F. Ajili, Fakayode O. Enoch, Wasfi Farès, Fatma Abdelmoula, Fausta Mosha, Faustinos Tatenda Takawira, Fawzi Derrar, Fériel Bouzid, Onikepe Folarin, Fowotade Adeola, Francisca Muyembe, Frank Tanser, Fred Athanasius Dratibi, Gabriel K. Mbunsu, Gaëtan Thilliez, Gemma L. Kay, George Githinji, Gert U. van Zyl, Gordon A. Awandare, Grit Schubert, Gugu Maphalala, Hafaliana C. Ranaivoson, Hajar Lemriss, Anise Happi, Haruka Abe, Héla Karray, Hellen Nansumba, Hesham A. Elgahzaly, Hlanai Gumbo, Ibtihel Smeti, Ikhlas Ben Ayed, Ikponmwosa Odia, Ilhem Boutiba Ben Boubaker, Imed Gaâloul, Inbal Gazy, Innocent Mudau, Isaac Ssewanyana, Iyaloo Konstantinus, Jean B. Lekana-Douk, Jean-Claude Makangara-Cigolo, Jean‐Jacques Muyembe Tamfum, Jean‐Michel Héraud, Jeffrey G. Shaffer, Jennifer Giandhari, Jingjing Li, Jiro Yasuda, Joana Q. Mends, Jocelyn Kiconco, John Mwita Morobe, John O. Gyapong, Johnson Okolie, John Kayiwa, Johnathan A. Edwards, Jones Gyamfi, Jouali Farah, Joweria Nakaseegu, Joyce M. Ngoi, Joyce Namulondo, Julia C. Andeko, Julius J. Lutwama, Justin O’Grady, Katherine J. Siddle, Kayode T. Adeyemi, Kefentse A. Tumedi, Khadija Said Mohammed, Hae‐Young Kim, Kwabena Obeng Duedu, Lahcen Belyamani, Lamia Fki‐Berrajah, Lavanya Singh, Leonardo de Oliveira Martins, Lynn Tyers, Magalutcheemee Ramuth, Maha Mastouri, Mahjoub Aouni, Mahmoud El Hefnawi, M.I. Matsheka, Malebogo Kebabonye, Mamadou Diop, Manel Turki, Mariétou F Paye, Martin M. Nyaga, Mathabo Mareka, Damaris Matoke-Muhia, Maureen W. Mburu, Maxmillian Mpina, Nwando Mba, Michael Owusu, Michael R. Wiley, Mirabeau T. Youtchou, Mitoha Ondo’o Ayekaba, Mohamed Abouelhoda, Mohamed G. Seadawy, Mohamed K. Khalifa, Mooko Sekhele, Mouna Ouadghiri, Moussa Moïse Diagne, Mulenga Mwenda, Mushal Allam, My V. T. Phan, Nabil Abid, Nadia Touil, Nadine Rujeni, Najla Kharrat, Nália Ismael, Ndongo Dia, Nédio Mabunda, Marvin Hsiao, Nelson Boricó Silochi, Ngoy Nsenga, Nicksy Gumede, Nicola Mulder, Nnaemeka Ndodo, Norosoa Harline Razanajatovo, Nosamiefan Iguosadolo, Judith U. Oguzie, Ojide C. Kingsley, Okogbenin Sylvanus, Okokhere Peter, Femi Oladiji, Idowu B. Olawoye, Testimony Olumade, Omoruyi Ewean Chukwuma, Onwe Emeka Ogah, Chika Onwuamah, Oshomah Cyril, Ousmane Faye, Oyewale Tomori, Pascale Ondoa, P Combe, Patrick Semanda, Paul E. Oluniyi, Paulo Arnaldo, Peter K. Quashie, Philippe Dussart, Phillip Armand Bester, Placide Mbala, Reuben Ayivor-Djanie, Richard Njouom, Richard Odame Phillips, Richmond Gorman, Robert A. Kingsley, Rosina Carr, Saâd El Kabbaj, Saba Gargouri, Saber Masmoudi, Safiétou Sankhe, Salako B. Lawal, Samar K. Kassim, Sameh Trabelsi, Samar Metha, S. Kammoun, Sanaâ Lemriss, Sara H. A. Agwa, Sébastien Calvignac‐Spencer, S. F. Schaffner, Seydou Doumbia, Sheila Makiala Mandanda, Sherihane Aryeetey, Shymaa S. Ahmed, Siham Elhamoumi, S. F. Andriamandimby, Sobajo Tope, Sonia Etenna Lekana-Douki, Sophie J. Prosolek, Soumeya Ouangraoua, Steve Ahuka Mundeke, Steven Rudder, Sumir Panji, Sureshnee Pillay, Susan Engelbrecht, Susan Nabadda, Sylvie Behillil, Sylvie L. Budiaki, Sylvie van der Werf, Tapfumanei Mashe, Tarik Aanniz, Thabo Mohale, Thanh Le-Viet, Tobias Schindler, Ugochukwu J. Anyaneji, Chinedu Ugwu, Upasana Ramphal, Uwanibe Jessica, Uwem E. George, Vagner Fonseca, Vincent Enouf, Vivianne Gorova, Wael H. Roshdy, William Ampofo, Wolfgang Preiser, Wonderful T. Choga, Yaw Bediako, Yeshnee Naidoo, Yvan Butera, Zaydah R. de Laurent, Amadou A. Sall, Ahmed Rebaï, Anne von Gottberg, Bouréma Kouriba, Carolyn Williamson, Daniel J. Bridges, Ihekweazu Chikwe, Jinal N. Bhiman, Madisa Mine, Matthew Cotten, Sikhulile Moyo, Simani Gaseitsiwe, Ngonda Saasa, Pardis C. Sabeti,
SARS-CoV-2 across Africa The impact of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic has been hard to track in African countries, largely because of patchy data. Wilkinson et al . curated viral genomes collected in 2021 from several countries across the continent. Outbreaks during 2020 in each African country were initiated by imported cases, mostly from Europe. As the pandemic developed, case numbers in African countries were likely many times higher than reported, and ...
American Association for the Advancement of Science
Houriiyah Tegally, James Emmanuel San, Matthew Cotten, Monika Moir, Bryan Tegomoh, Gerald Mboowa, Darren P. Martin, Cheryl Baxter, Arnold W. Lambisia, Amadou Diallo, Daniel G. Amoako, Moussa Moïse Diagne, Abay Sisay, Abdel‐Rahman N. Zekri, Abdou Salam Guèye, Abdoul Karim Sangaré, Abdoul–Salam Ouédraogo, Abdourahmane Sow, Abdualmoniem O. Musa, Abdul Karim Sesay, Abe G. Abias, Adam Elzagheid, Adamou Lagaré, Adedotun-Sulaiman Kemi, Aden Elmi Abar, Adeniji A. Johnson, Adeola Fowotade, Oluwapelumi O. Adeyemi, Adrienne Amuri-Aziza, Agnes Juru, Ahmed Kandeil, Ahmed Mostafa, Ahmed Rebaï, Ahmed Sayed, Kazeem Akano, Aladje Baldé, Alan Christoffels, Alexander J. Trotter, Allan Campbell, Alpha Kabinet Keïta, A. Koné, Amal Bouzid, Amal Souissi, Ambrose Agweyu, Amel Naguib, Ana Victoria Gutiérrez, Anatole Nkeshimana, Andrew J. Page, Anges Yadouléton, Anika Vinzé, Anise N. Happi, Anissa Chouikha, Arash Iranzadeh, Arisha Maharaj, Armel L. Batchi‐Bouyou, Arshad Ismail, Augustina Angelina Sylverken, Augustine Goba, Femi Ayoade, Ayotunde E. Sijuwola, Baba M, Babatunde Lawal Salako, Bamidele Soji Oderinde, Bankole Bolajoko, Bassirou Diarra, Belinda L. Herring, Benjamin Tsofa, Bernard Lekana-Douki, Bernard Mvula, Berthe‐Marie Njanpop‐Lafourcade, Blessing T. Marondera, Bouh Abdi Khaireh, Bouréma Kouriba, Bright Adu, Brigitte Pool, Bronwyn McInnis, Cara E. Brook, Carolyn Williamson, Cassien Nduwimana, Catherine Anscombe, Catherine Pratt, Cathrine Scheepers, Chantal Akoua‐Koffi, Charles N. Agoti, Chastel M. Mapanguy, Cheikh Loucoubar, Chika Onwuamah, Chikwe Ihekweazu, Christian Malaka, Christophe N. Peyrefitte, Chukwa Grace, Chukwuma Ewean Omoruyi, Clotaire Donatien Rafaï, Collins M. Morang’a, Cyril Erameh, Daniel Lule Bugembe, Daniel J. Bridges, Daniel Mukadi‐Bamuleka, Daniel J. Park, David A. Rasmussen, David Baker, D. James Nokes, Deogratius Ssemwanga, Derek Tshiabuila, Dominic S. Y. Amuzu, Dominique Goedhals, Donald S. Grant, Donwilliams O. Omuoyo, Dorcas Maruapula, Dorcas Wanjohi, Ebenezer Foster-Nyarko, Eddy Kinganda-Lusamaki, Edgar Simulundu, Edidah M. Ong’era, Edith N. Ngabana, Edward Okoth Abworo, Edward Otieno, Edwin Shumba, Edwine Barasa, El Bara Ahmed, Elhadi Abdalla Ahmed, Emmanuel Lokilo, Enatha Mukantwari, Eromon Philomena, Essia Belarbi, Etienne Simon‐Lorière, Etilé A. Anoh, Eusébio Manuel, Fabian H. Leendertz, Fahn Taweh, Wasfi Farès, Fatma Abdelmoula, Faustinos Tatenda Takawira, Fawzi Derrar, Fehintola V. Ajogbasile, Florette K. Treurnicht, Onikepe Folarin, Francine Ntoumi, Francisca Muyembe, Frank Edgard Zongo Ragomzingba, Fred Athanasius Dratibi, Fred-Akintunwa Iyanu, Gabriel K. Mbunsu, Gaetän Thilliez, Gemma L. Kay, George O. Akpede, Gert U. van Zyl, Gordon A. Awandare, Grace Kpeli, Grit Schubert, Gugu Maphalala, Hafaliana C. Ranaivoson, Hannah E. Omunakwe, Harris Onywera, Haruka Abe, Héla Karray, Hellen Nansumba, Henda Triki, Herve Albéric Adje Kadjo, Hesham A. Elgahzaly, Hlanai Gumbo, Hota Mathieu, Hugo Kavunga‐Membo, Ibtihel Smeti, Idowu B. Olawoye, Ifedayo Adetifa, Ikponmwosa Odia, Ilhem Boutiba Ben Boubaker, Iluoreh Ahmed Muhammad, Isaac Ssewanyana, Isatta Wurie, Iyaloo Konstantinus, Jacqueline Wemboo Afiwa Halatoko, James Ayei, Janaki Sonoo, Jean-Claude Makangara-Cigolo, Jean‐Jacques Muyembe Tamfum, Jean‐Michel Héraud, Jeffrey G. Shaffer, Jennifer Giandhari, Jennifer Musyoki, Jerome Nkurunziza, Jessica N. Uwanibe, Jinal N. Bhiman, Jiro Yasuda, Joana Morais, Jocelyn Kiconco, John Demby Sandi, John Huddleston, John Kofi Odoom, John Mwita Morobe, John O. Gyapong, John Kayiwa, Johnson Okolie, Joicymara S. Xavier, Jones Gyamfi, Joseph Francis Wamala, Joseph Humphrey Kofi Bonney, Joseph Nyandwi, Josie Everatt, Joweria Nakaseegu, Joyce M. Ngoi, Joyce Namulondo, Judith U. Oguzie, Julia C. Andeko, Julius J. Lutwama, Juma J. H. Mogga, Justin O’Grady, Katherine J. Siddle, Kathleen Victoir, Kayode T. Adeyemi, Kefentse A. Tumedi, Kevin Sanders Da Rosa Carvalho, Khadija Said Mohammed, Koussay Dellagi, Kunda Musonda, Kwabena Obeng Duedu, Lamia Fki‐Berrajah, Lavanya Singh, Lenora Kepler, Leon Biscornet, Leonardo de Oliveira Martins, Lucious Chabuka, Luicer A. Ingasia, Lul Deng Ojok, Lul Lojok Deng, Lynette Isabella Ochola‐Oyier, Lynn Tyers, Madisa Mine, Magalutcheemee Ramuth, Maha Mastouri, Mahmoud ElHefnawi, Maïmouna Mbanne, M.I. Matsheka, Malebogo Kebabonye, Mamadou Diop, Mambu Momoh, Maria da Luz Lima Mendonça, Marietjie Venter, Mariétou F Paye, Martin Faye, Martin M. Nyaga, Mathabo Mareka, Damaris Matoke-Muhia, Maureen W. Mburu, Maxmillian Mpina, Michael Owusu, Michael R. Wiley, Mirabeau Youtchou Tatfeng, Mitoha Ondo’o Ayekaba, Mohamed Abouelhoda, Mohamed Amine Beloufa, Mohamed G. Seadawy, Mohamed K. Khalifa, Mooko Marethabile Matobo, Mouhamed Kane, Mounérou Salou, Mphaphi B. Mbulawa, Mulenga Mwenda, Mushal Allam, My V. T. Phan, Nabil Abid, Nadine Rujeni, Nadir Abuzaid, Nália Ismael, Nancy Elguindy, Ndeye Marième Top, Ndongo Dia, Nédio Mabunda, Marvin Hsiao, Nelson Boricó Silochi, Ngiambudulu M. Francisco, Ngonda Saasa, Nicholas Bbosa, Nickson Murunga, Nicksy Gumede, Nicole Wolter, Nikita Sitharam, Nnaemeka Ndodo, Nnennaya Anthony Ajayi, Noël Tordo, Nokuzola Mbhele, Norosoa Harline Razanajatovo, Nosamiefan Iguosadolo, Nwando Mba, Ojide C. Kingsley, Okogbenin Sylvanus, Femi Oladiji, Moses Olubusuyi Adewumi, Testimony Olumade, Olusola Ogunsanya, Oluwatosin Fakayode, Onwe Emeka Ogah, Ope-Ewe Oludayo, Ousmane Faye, Pamela Smith-Lawrence,
Investment in severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) sequencing in Africa over the past year has led to a major increase in the number of sequences that have been generated and used to track the pandemic on the continent, a number that now exceeds 100,000 genomes. Our results show an increase in the number of African countries that are able to sequence domestically and highlight that local sequencing enables faster turnaround times and more-regular routine surveillance. Despite ...
American Association for the Advancement of Science
Sonia Etenna Lekana-Douki, Nadine N’dilimabaka, Anthony Levasseur, Philippe Colson, Julia C. Andeko, Ornella Zong Minko, Octavie Banga Mve-Ella, Pierre‐Edouard Fournier, Christian Devaux, Bertrand Mve Ondo, Falone Larissa Akombi, Laurianne Yacka Mouele Bolo, Audrey Michel Ngonga Dikongo, Abdoulaye Diané, Arsène Mabika Mabika, Jenny Francine Mathouet, Cresh Dzembo, Nick Chenis Atiga, Anicet Mouity Matoumba, Nal Kennedy Ndjangangoye, Ludivine Bréchard, Marielle Bedotto-Buffet, Joa Braïthe Mangombi Pambou, Marisca Kandet Yattara, Elvire Anita Mbongo Nkama, Armel Mintsa Ndong, Ayôla Akim Adégnika, Didier Raoult, Florence Fenollar, Jean-Bernard Lékana-Douki,
Since the onset of the COVID-19 pandemic, the SARS-CoV-2 viral dynamics in Africa have been less documented than on other continents. In Gabon, a Central African country, a total number of 37,511 cases of COVID-19 and 281 deaths have been reported as of December 8, 2021. After the first COVID-19 case was reported on March 12, 2020, in the capital Libreville, the country experienced two successive waves. The first one, occurred in March 2020 to August 2020, and the second one in January 2021 to May ...
Tópico(s): SARS-CoV-2 detection and testing
2022 - Frontiers Media | Frontiers in Medicine
Sonia Etenna Lekana-Douki, Pater Noster Sir-Ondo-Enguier, Octavie Banga-Mve-Ella, Roméo Karl Imboumy-Limoukou, Gaël Darren Maganga, Jean-Bernard Lékana-Douki, Nicolás Berthet,
Measles is one of the most infectious diseases with a high mortality rate worldwide. It is caused by the measles virus (MeV) which is a single stranded RNA virus with genetic diversity based on the nucleoprotein gene, including 24 genotypes. In Gabon, several outbreaks occurred in the past few years, especially in 2016 in Libreville and Oyem. A surveillance network of infectious diseases highlighted a measles outbreak which occurred in the south of Gabon from April to June 2017. Clinical specimens ...
Tópico(s): Vaccine Coverage and Hesitancy
2019 - BioMed Central | BMC Infectious Diseases
Carlo Fischer, Tongai Maponga, Anges Yadouléton, Nuro Abílio, Emmanuel Aboce, Praise Adewumi, Pedro Afonso, Jewelna Akorli, Soa Fy Andriamandimby, Latifa Anga, Yvonne Ashong, Mohamed Amine Beloufa, Aïcha Bensalem, Richard J. Birtles, Anicet Luc Magloire Boumba, Freddie Bwanga, Mike Chaponda, Paradzai Chibukira, R Matthew Chico, Justin Chileshe, Gershom Chongwe, Assana Cissé, Umberto D’Alessandro, Xavier de Lamballerie, Joana Morais, Fawzi Derrar, Ndongo Dia, Youssouf Diarra, Lassina Doumbia, Christian Drosten, Philippe Dussart, Richard Echodu, Yannik Eggers, Abdelmajid Eloualid, Ousmane Faye, Torsten Feldt, Anna Frühauf, Afiwa Halatoko, Pauliana-Vanessa Ilouga, Nália Ismael, Ronan Jambou, Sheikh Jarju, Antje Kamprad, Ben Katowa, John Kayiwa, Leonard Kingwara, Ousmane Koita, Vincent Lacoste, Adamou Lagaré, Olfert Landt, Sonia Etenna Lekana-Douki, Jean Bernard Lékana-Douki, Etuhole Iipumbu, Hugues Loemba, Julius J. Lutwama, Santou Mamadou, Issaka Maman, Brendon Manyisa, Pedro A. Martinez, Japhet Matoba, Lusia Mhuulu, Andrés Moreira‐Soto, Judy Mwangi, Nadine N ́dilimabaka, Charity Angella Nassuna, Mamadou Ousmane Ndiath, Emmanuel Nepolo, Richard Njouom, Jalal Nourlil, Steven Ger Nyanjom, Eddy Okoth Odari, Alfred Okeng, Jean Bienvenue Ouoba, Michael Owusu, Irene Owusu Donkor, Karabo Kristen Phadu, Richard Odame Phillips, Wolfgang Preiser, Vurayai Ruhanya, Fortune Salah, Sourakatou Salifou, Amadou Alpha Sall, Augustina Angelina Sylverken, Paul Alain Tagnouokam‐Ngoupo, Zékiba Tarnagda, Francis Olivier Tchikaya, Tafese Beyene Tufa, Jan Felix Drexler,
The geographic and evolutionary origins of the SARS-CoV-2 Omicron variant (BA.1), which was first detected mid-November 2021 in Southern Africa, remain unknown. We tested 13,097 COVID-19 patients sampled between mid-2021 to early 2022 from 22 African countries for BA.1 by real-time RT-PCR. By November-December 2021, BA.1 had replaced the Delta variant in all African sub-regions following a South-North gradient, with a peak Rt of 4.1. Polymerase chain reaction and near-full genome sequencing data ...
Tópico(s): Viral Infections and Outbreaks Research
2022 - American Association for the Advancement of Science | Science
Jean-Bernard Lékana Douki, Boubacar Traoré, Fábio Trindade Maranhão Costa, Thierry Fusaı̈, Bruno Pouvelle, Yvon Sterkers, Artur Scherf, Jürg Gysin,
Plasmodium falciparum parasites express variant adhesion molecules on the surface of infected erythrocytes (IEs), which act as targets for natural protection. Recently it was shown that IE sequestration in the placenta is mediated by binding to chondroitin sulfate A via the duffy binding-like (DBL)–γ3 domain ofP falciparum erythrocyte membrane protein 1 (PfEMP1CSA). Conventional immunization procedures rarely result in the successful production of monoclonal antibodies (mAbs) against such conformational ...
Tópico(s): Complement system in diseases
2002 - Elsevier BV | Blood
Peter Neuenschwander, J. d’A. Hughes, F. Ogbe, J. M. Ngatse, J. P. Legg,
... collected in August 1999 from nine fields in Lekana, N'Sah and Abala-Ndolo in the central ...
Tópico(s): Plant-Microbe Interactions and Immunity
2002 - Wiley | Plant Pathology
Fábio Trindade Maranhão Costa, Thierry Fusaı̈, Daniel Parzy, Yvon Sterkers, Marylin Torrentino, Jean-Bernard Lékana Douki, Boubacar Traoré, Stéphane Pêtres, Artur Scherf, Jürg Gysin,
Maternal malaria is associated with the sequestration, in the placenta, of Plasmodium falciparum-infected erythrocytes onto chondroitin sulfate A (CSA), via the duffy binding-like (DBL)-gamma3 domain of the P. falciparum erythrocyte membrane protein 1 (PfEMP1(CSA)) (DBL-gamma3(CSA)). The production of antibodies against CSA-binding infected erythrocytes (IEs(CSA)) is correlated with resistance to maternal malaria in multiparous women. We produced recombinant DBL-gamma3(CSA) (rDBL-gamma3(CSA)) in insect ...
Tópico(s): Research on Leishmaniasis Studies
2003 - Oxford University Press | The Journal of Infectious Diseases
Jean-Bernard Lekana Douki, Yvon Sterkers, Catherine Lépolard, Boubacar Traoré, Fábio Trindade Maranhão Costa, Artur Scherf, Jürg Gysin,
Abstract Recent findings have challenged the current view of Plasmodium falciparum (P falciparum) blood-stage biology by demonstrating the cytoadhesion of early ring-stage–infected erythrocytes (rIEs) to host endothelial cells and placental syncytiotrophoblasts. The adhesion of rIEs was observed only in parasites that bind to the placenta via chondroitin sulfate A (CSA). In this work, a panel of mouse monoclonal antibodies (mAbs) that specifically inhibit cytoadhesion of rIEs but not of mature IEs was ...
Tópico(s): Complement system in diseases
2003 - Elsevier BV | Blood
Sonia Lekana-Douki Etenna, Mélanie Caron, Guillaume Besson, Maria Makuwa, Antoine Gessain, A. Mahé, Mirdad Kazanji,
Human T-cell leukemia virus type 1 (HTLV-1) is highly endemic in areas of central Africa; mother-to-child transmission and sexual transmission are considered to be the predominant routes. To determine the prevalence and subtypes of HTLV-1/2 in pregnant women in Gabon, we conducted an epidemiological survey in the five main cities of the country. In 907 samples, the HTLV-1 seroprevalence was 2.1%, which is lower than that previously reported. Only one case of HTLV-2 infection was found. The HTLV-1 ...
Tópico(s): Vector-Borne Animal Diseases
2008 - American Society for Microbiology | Journal of Clinical Microbiology
Estelle S. Zang-Edou, Ulrick Bisvigou, Zacharie Taoufiq, Faustin Lékoulou, Jean Bernard Lékana-Douki, Yves Traoré, Dominique Mazier, Fousseyni Toure-Ndouo,
Plasmodium falciparum infection can abruptly progress to severe malaria, a life-threatening complication resulting from sequestration of parasitized red blood cells (PRBC) in the microvasculature of various organs such as the brain and lungs. PRBC adhesion can induce endothelial cell (EC) activation and apoptosis, thereby disrupting the blood-brain barrier. Moreover, hemozoin, the malarial pigment, induces the erythroid precursor apoptosis. Despite the current efficiency of antimalarial drugs in killing ...
Tópico(s): Hemoglobinopathies and Related Disorders
2010 - Public Library of Science | PLoS ONE
Mélanie Caron, Guillaume Besson, Sonia Lekana-Douki Etenna, Armel Mintsa-Ndong, Spyridon Mourtas, Antonia Radaelli, Carlo De Giuli Morghen, Roberta Loddo, Paolo La Colla, Sophia G. Antimisiaris, Mirdad Kazanji,
Tópico(s): Herpesvirus Infections and Treatments
2010 - Elsevier BV | Virology
Gilda Grard, Jan Felix Drexler, Sonia Etenna Lekana-Douki, M Caron, Alexander N. Lukashev, Dieudonné Nkoghe, Jean‐Paul Gonzalez, Christian Drosten, Eric M. Leroy,
An outbreak of flaccid paralysis syndrome in adults is ongoing in Congo. Molecular analysis of faecal, throat and cerebrospinal samples identified wildtype 1 poliovirus and an additional enterovirus C strain related to enterovirus 109 as the cause. As of 22 November, the cumulative number of cases was 409, of which 169 (41.3%) were fatal. This is one of the largest wild type 1 poliovirus outbreaks ever described associated with an unusually high case fatality rate.
Tópico(s): Whipple's Disease and Interleukins
2010 - European Centre for Disease Prevention and Control | Eurosurveillance
Jean Bernard Lékana-Douki, Jean Bernard Bongui, Sandrine Lydie Oyegue Liabagui, Sonya Estelle Zang Edou, Rafika Zatra, Ulrich Bisvigou, Pierre Druilhe, Jacques Lébibi, Fousseyni Samba Toure Ndouo, Maryvonne Kombila,
As part of a project to identify new compounds active on malarial parasites, we tested the in vitro antiplasmodial activity of nine plants traditionally used to treat malaria symptoms in Haut-Ogooué Province, South-East Gabon.Dichloromethane and methanolic extracts of each plant were tested for their antiplasmodial activity on two chloroquine-resistant strains of Plasmodium falciparum (FCB and W2), based on lactate dehydrogenase activity. Cytotoxicity was assessed with the MTT test on MRC-5 human ...
Tópico(s): African Botany and Ecology Studies
2010 - Elsevier BV | Journal of Ethnopharmacology
Marielle Karine Bouyou-Akotet, S. Nzenze-Afene, Edgard Brice Ngoungou, Éric Kendjo, Mathieu Owono-Medang, Jean-Bernard Lékana-Douki, Ghislaine Obono-Obiang, M Mounanga, Maryvonne Kombila,
The new recommendations to prevent malaria in pregnant women have recently been implemented in Gabon. There is little information on the pregnancy indicators that are useful for their evaluation. A cross-sectional study for the assessment of the prevalence of peripheral, placental, and cord malaria and anemia among delivering women was performed at the largest public hospital of Gabon. Malaria prevalence was 34.4%, 53.6%, and 18.2% for maternal peripheral, placental, and cord blood respectively, ...
Tópico(s): Mosquito-borne diseases and control
2010 - American Society of Tropical Medicine and Hygiene | American Journal of Tropical Medicine and Hygiene
Jean Bernard Lékana-Douki, Sylvatrie Danne Dinzouna Boutamba, Rafika Zatra, Sonya Estelle Zang Edou, Hervé Ekomy, Ulrick Bisvigou, Fousseyni Toure-Ndouo,
Despite global antimalarial measures, Plasmodium falciparum malaria remains a major public health problem. WHO has recommended the use of arteminisin-based combination therapy to limit the emergence of antimalarial drug resistance. However, ACT treatment failures have been linked to the selection of the wild types 86N genotype of P. falciparum multidrug resistance 1 (Pfmdr1) and the 76K genotype of P. falciparum chloroquine resistance (Pfcrt) genes. The aim of this study was to investigate the molecular ...
Tópico(s): Mosquito-borne diseases and control
2011 - Elsevier BV | Infection Genetics and Evolution
Jean Bernard Lékana-Douki, Sandrine Lydie Oyegue Liabagui, Jean Bernard Bongui, Rafika Zatra, Jacques Lébibi, Fousseyni Toure-Ndouo,
Malaria remains a major public health problem, especially in tropical and subtropical regions because of the emergence and widespread of antimalarial drug resistance. Traditional medicine represents one potential source of new treatments. Here, we investigated the in vitro antiplasmodial activity of bark extracts from two Fabaceae species (Tetrapleura tertaptera and Copaifera religiosa) traditionally used to treat malaria symptoms in Haut-Ogooué province, Gabon. The antiplasmodial activity of dichloromethane ...
Tópico(s): Ethnobotanical and Medicinal Plants Studies
2011 - BioMed Central | BMC Research Notes
Joseph Privat Ondo, Jean Bernard Lékana-Douki, Jean‐Bernard Bongui, E. S. Zang Edou, Rafika Zatra, Fousseyni Toure-Ndouo, Abdelhakim Elomri, Jacques Lébibi, Elisabeth Seguin,
Abstract Vitex madiensis Oliv. (Lamiaceae) is traditionally used to treat malaria symptoms in Haut‐Ogooué, Gabon. Leaves and stem barks extracts were obtained using dichloromethane (CH 2 Cl 2 ), ethyl acetate (EtOAc) and methanol (MeOH) as extraction solvents and fractionated on silica gel column. The in vitro antiplasmodial activity of CH 2 Cl 2 , EtOAc and MeOH extracts and fractions was evaluated against the chloroquine‐resistant FCB strain and field isolates of Plasmodium falciparum using the DELI test. ...
Tópico(s): Traditional and Medicinal Uses of Annonaceae
2011 - Wiley | Tropical Medicine & International Health
Gabin Mwande-Maguene, Jouda Jakhlal, Jean-Bernard Lékana-Douki, Elisabeth Mouray, Till Bousquet, Sylvain Pellegrini, Philippe Grellier, Fousseyni Samba Toure Ndouo, Jacques Lébibi, Lydie Pélinski,
An efficient synthesis of 1,4-benzodiazepin-2-ones is described by condensation between 2-aminobenzophenone and Boc-protected amino acids via microwave-assisted irradiation. This produces higher yields in shorter reaction times than with traditional methods. The antiplasmodial activity of the corresponding ferrocenyl benzodiazepines was evaluated in vitro against Plasmodium falciparum F32 (chloroquine-sensitive) and FCB1 and K1 (chloroquine-resistant) strains and gabonese clinical isolates.
Tópico(s): Synthesis and Biological Evaluation
2011 - Royal Society of Chemistry | New Journal of Chemistry
Jean-Bernard Lékana-Douki, Julie Pontarollo, Rafika Zatra, Fousseyni Toure-Ndouo,
Despite progress in the control of malaria, it remains a serious public health problem. Substantial declines in malaria transmission, morbidity and mortality have nonetheless been reported in several countries where new malaria control strategies have been implemented. We conducted this molecular and epidemiological analysis of malaria in the pediatric department of the Chinese-Gabon Friendship Hospital (HCGC) in Franceville in 2010. Franceville is the third largest town in Gabon, and malaria transmission ...
Tópico(s): Parasites and Host Interactions
2011 - John Libbey Eurotext | Cahiers de Santé
Rafika Zatra, Jean Bernard Lékana-Douki, Faustin Lékoulou, Ulrick Bisvigou, Edgard Brice Ngoungou, Fousseyni Samba Toure Ndouo,
Abstract Background Malaria remains a major public health problem, due largely to emergence and widespread P. falciparum drug resistance. WHO recommends artemisinine combination based therapy (ACT) to overcome P. falciparum drug resistance, but reports of declining ACT efficacy have been published. A thorough understanding of the molecular bases of P. falciparum resistance to existing drugs is therefore needed. The aims of this study were to analyze the in vitro sensitivity of P. falciparum field ...
Tópico(s): Computational Drug Discovery Methods
2012 - BioMed Central | BMC Infectious Diseases
Mélanie Caron, Sonia Etenna Lekana-Douki, Maria Makuwa, Guy-Patrick Obiang-Ndong, Olivia Biba, Dieudonné Nkoghe, Mirdad Kazanji,
Abstract Background In Africa, the wide genetic diversity of HIV has resulted in emergence of new strains, rapid spread of this virus in sub-Saharan populations and therefore spread of the HIV epidemic throughout the continent. Methods To determine the prevalence of antibodies to HIV among a high-risk population in Gabon, 1098 and 2916 samples were collected from pregnant women in 2005 and 2008, respectively. HIV genotypes were evaluated in 107 HIV-1-positive samples to determine the circulating ...
Tópico(s): HIV/AIDS Research and Interventions
2012 - BioMed Central | BMC Infectious Diseases
Mirdad Kazanji, Augustin Mouinga‐Ondémé, Sonia Lekana-Douki-Etenna, Mélanie Caron, Maria Makuwa, Renaud Mahieux, Antoine Gessain,
Of 78 Gabonese individuals who had received bites from nonhuman primates (NHPs) while hunting, 7 were infected with human T lymphotropic virus (HTLV-1). Five had been bitten by gorillas and were infected with subtype B strains; however, a 12-year-old girl who was severely bitten by a Cercopithecus nictitans was infected with a subtype D strain that was closely related to the simian T lymphotropic virus (STLV-1) that infects this monkey species. Her mother was infected with a subtype B strain. These ...
Tópico(s): Vector-Borne Animal Diseases
2014 - Oxford University Press | The Journal of Infectious Diseases
Sonia Etenna Lekana-Douki, Dieudonné Nkoghe, Christian Drosten, Edgar Brice Ngoungou, Jan Felix Drexler, Eric M. Leroy,
Surveillance of influenza-like illness (ILI) in Central Africa began only recently, and few data are therefore available on the circulation of influenza virus and other respiratory viruses. In Gabon, a Central African country, we established a surveillance network in four major towns in order to analyze cases of ILI among patients who visited health centers between March 2010 and June 2011, and to determine the viral etiology. Nasal swabs were sent for analysis to the Centre International de Recherches ...
Tópico(s): Viral Infections and Vectors
2014 - BioMed Central | BMC Infectious Diseases
Jan Felix Drexler, Gilda Grard, Alexander N. Lukashev, Liubov I. Kozlovskaya, Sindy Böttcher, Gökhan Uslu, Johan Reimerink, Anatoly P. Gmyl, Raphaël Taty-Taty, Sonia Etenna Lekana-Douki, Dieudonné Nkoghe, Anna Maria Eis‐Hübinger, Sabine Diedrich, Marion Koopmans, Eric M. Leroy, Christian Drosten,
Significance In 2010, a large outbreak of poliomyelitis involving 445 laboratory-confirmed cases occurred in the Republic of Congo. The 47% case-fatality rate was unusually high. Outbreak severity was attributed to low immunization coverage but vaccine-mediated immunity against the outbreak virus was never investigated. We isolated the poliovirus type 1 responsible for the outbreak and located its evolutionary origins to Southeast Asia. Fatal cases showed evidence for previous vaccination against ...
Tópico(s): SARS-CoV-2 and COVID-19 Research
2014 - National Academy of Sciences | Proceedings of the National Academy of Sciences
Gabin Mwande-Maguene, Jean-Bernard Lékana-Douki, Elisabeth Mouray, Till Bousquet, Philippe Grellier, Sylvain Pellegrini, Fousseyni Samba Toure Ndouo, Jacques Lébibi, Lydie Pélinski,
The aim of this study was to synthesize a series of ferrocenyl 4-aminoquinolines and to evaluate their activities against Plasmodium falciparum F32 (chloroquine-sensitive) and FCB1 and K1 (chloroquino-resistant). Some of the ferrocenyl compounds exhibited in vitro antiplasmodial activity in the nM range. In particular, (1R,4R)-N1-(7-chloroquinolin-4-yl)-N4-(ferrocenylmethyl)-N4-methylcyclohexane-1,4-diamine 17 presented the lowest IC50 value (26 nM) against CQ-resistant strains.
Tópico(s): Synthesis and Biological Evaluation
2014 - Elsevier BV | European Journal of Medicinal Chemistry
Oleg Mediannikov, Cristina Socolovschi, Sophie Edouard, Florence Fenollar, Nadjet Mouffok, Hubert Bassène, Georges Diatta, Adama Tall, Hamidou Niangaly, Ogobara K. Doumbo, Jean Bernard Lékana-Douki, Abir Znazen, M’hammed Sarih, Pavel Ratmanov, Hervé Richet, Mamadou Ousmane Ndiath, Cheikh Sokhna, Philippe Parola, Didier Raoult,
Abstract This study aimed to compare the epidemiology of Rickettsia felis infection and malaria in France, North Africa, and sub-Saharan Africa and to identify a common vector. Blood specimens from 3,122 febrile patients and from 500 nonfebrile persons were analyzed for R. felis and Plasmodium spp. We observed a significant linear trend (p<0.0001) of increasing risk for R. felis infection. The risks were lowest in France, Tunisia, and Algeria (1%), and highest in rural Senegal (15%). Co-infections ...
Tópico(s): Parasites and Host Interactions
2013 - Centers for Disease Control and Prevention | Emerging infectious diseases
Gaël Mourembou, Jean Bernard Lékana-Douki, Oleg Mediannikov, Sydney Maghendji Nzondo, Lady Charlène Kouna, Jean Claude Biteghe-Bi-Essone, Florence Fenollar, Didier Raoult,
Rickettsia felis has been reported to be a cause of fever in sub-Saharan Africa, but this association has been poorly evaluated in Gabon. We assessed the prevalence of this bacterium among children <15 years of age in 4 areas of Gabon; the locations were in urban, semiurban, and rural areas. DNA samples from 410 febrile children and 60 afebrile children were analyzed by quantitative PCR. Overall, the prevalence of R. felis among febrile and afebrile children was 10.2% (42/410 children) and 3.3% (2/ ...
Tópico(s): Yersinia bacterium, plague, ectoparasites research
2015 - Centers for Disease Control and Prevention | Emerging infectious diseases