Browsing by Author "Randrianarivelojosia, M."
Now showing 1 - 5 of 5
Results Per Page
Sort Options
Item K13-propeller polymorphisms in plasmodium falciparum parasites from sub-saharan Africa(Journal of Infectious Diseases, 2015-01) Kamau, E.; Campino, S.; Amenga-Etego, L.; Drury, E.; Ishengoma, D.; Johnson, K.; Mumba, D.; Kekre, M.; Yavo, W.; Mead, D.; Bouyou-Akotet, M.; Apinjoh, T.; Golassa, L.; Randrianarivelojosia, M.; Andagalu B, B.; Maiga-Ascofare, O.; Amambua-Ngwa, A.; Tindana, P.; Ghansah, A.; Macinnis, B.; Kwiatkowski, D.; Djimde, A.A.Mutations in the Plasmodium falciparum K13-propeller domain have recently been shown to be important determinants of artemisinin resistance in Southeast Asia. This study investigated the prevalence of K13-propeller polymorphisms across sub-Saharan Africa. A total of 1212 P. falciparum samples collected from 12 countries were sequenced. None of the K13-propeller mutations previously reported in Southeast Asia were found, but 22 unique mutations were detected, of which 7 were nonsynonymous. Allele frequencies ranged between 1% and 3%. Three mutations were observed in >1 country, and the A578S was present in parasites from 5 countries. This study provides the baseline prevalence of K13-propeller mutations in sub-Saharan Africa. © 2015 The Author. Published by Oxford University Press on behalf of the Infectious Diseases Society of America. All rights reserved.Item Major subpopulations of Plasmodium falciparum in sub-Saharan Africa(Science, 2019-08-23) Amenga-Etego, L.; Amambua-Ngwa, A.; Kamau, E.; Amato, R.; Ghansah, A.; Golassa, L.; Randrianarivelojosia, M.; Ishengoma, D.; Apinjoh, T.; Maïga-Ascofaré, O.; Andagalu, B.; Yavo, W.; Bouyou-Akotet, M.; Kolapo, O.; Mane, K.; Worwui, A.; Jeffries, D.; Simpson, V.; D’Alessandro, U.; Kwiatkowski, D.; Djimde, A.A.Understanding genomic variation and population structure of Plasmodium falciparum across Africa is necessary to sustain progress toward malaria elimination. Genome clustering of 2263 P. falciparum isolates from 24 malaria-endemic settings in 15 African countries identified major western, central, and eastern ancestries, plus a highly divergent Ethiopian population. Ancestry aligned to these regional blocs, overlapping with both the parasite’s origin and with historical human migration. The parasite populations are interbred and shared genomic haplotypes, especially across drug resistance loci, which showed the strongest recent identity-by-descent between populations. A recent signature of selection on chromosome 12 with candidate resistance loci against artemisinin derivatives was evident in Ghana and Malawi. Such selection and the emerging substructure may affect treatment-based intervention strategies against P. falciparum malaria.Item Monitoring parasite diversity for malaria elimination in sub-Saharan Africa(Science, 2014-09) Ghansah, A.; Amenga-Etego, L.; Amambua-Ngwa, A.; Andagalu, B.; Apinjoh, T.; Bouyou-Akotet, M.; Cornelius, V.; Golassa, L.; Andrianaranjaka, V.H.; Ishengoma, D.; Johnson, K.; Kamau, E.; Maïga-Ascofaré, O.; Mumba, D.; Tindana, P.; Tshefu-Kitoto, A.; Randrianarivelojosia, M.; William, Y.; Kwiatkowski, D.P.; Djimde, A.A.The African continent continues to bear the greatest burden of malaria and the greatest diversity of parasites, mosquito vectors, and human victims. The evolutionary plasticity of malaria parasites and their vectors is a major obstacle to eliminating the disease. Of current concern is the recently reported emergence of resistance to the front-line drug, artemisinin, in South-East Asia in Plasmodium falciparum, which calls for preemptive surveillance of the African parasite population for genetic markers of emerging drug resistance. Here we describe the Plasmodium Diversity Network Africa (PDNA), which has been established across 11 countries in sub-Saharan Africa to ensure that African scientists are enabled to work together and to play a key role in the global effort for tracking and responding to this public health threat.Item An open dataset of Plasmodium falciparum genome variation in 7,000 worldwide samples(2021) MalariaGEN; Ahouidi, A.; Ali, M.; Almagro-Garcia, J.; Amambua-Ngwa, A.; Amaratunga, C.; Amato, R.; Amenga-Etego, L.; Andagalu, B.; Anderson, T.J.C.; Andrianaranjaka, V.; Apinjoh, T.; Ariani, C.; Ashley, E.A.; Auburn, S.; Awandare, G.A.; Ba, H.; Baraka, V.; Barry, A.E.; Bejon, P.; Bertin, G.I.; Boni, M.F.; Borrmann, S.; Bousema, T.; Branch, O.; Bull, P.C.; Busby, G.B.J.; Chookajorn, T.; Chotivanich, K.; Claessens, A.; Conway, D.; Craig, A.; D'Alessandro, U.; Dama, S.; Day, N.P.J.; Denis, B.; Diakite, M.; Djimdé, A.; Dolecek, C.; Dondorp, A.M.; Drakeley, C.; Drury, E.; Duffy, P.; Echeverry, D.F.; Egwang, T.G.; Erko, B.; Fairhurst, R.M.; Faiz, A.; Fanello, C.A.; Fukuda, M.M.; Gamboa, D.; Ghansah, A.; Golassa, L.; Goncalves, S.; Hamilton, W.L.; Harrison, G.L.A.; Hart, L.; Henrichs, C.; Hien, T.T.; Hill, C.A.; Hodgson, A.; Hubbart, C.; Imwong, M.; Ishengoma, D.S.; Jackson, S.A.; Jacob, C.G.; Jeffery, B.; Jeffreys, A.E.; Johnson, K.J.; Jyothi, D.; Kamaliddin, C.; Kamau, E.; Kekre, M.; Kluczynski, K.; Kochakarn, T.; Konaté, A.; Kwiatkowski, D.P.; Kyaw, M.P.; Lim, P.; Lon, C.; Loua, K.M.; Maïga-Ascofaré, O.; Malangone, C.; Manske, M.; Marfurt, J.; Marsh, K.; Mayxay, M.; Miles, A.; Miotto, O.; Mobegi, V.; Mokuolu, O.A.; Montgomery, J.; Mueller, I.; Newton, P.N.; Nguyen, T.; Nguyen, T.; Noedl, H.; Nosten, F.; Noviyanti, R.; Nzila, A.; Ochola-Oyier, L.I.; Ocholla, H.; Oduro, A.; Omedo, I.; Onyamboko, M.A.; Ouedraogo, J.; Oyebola, K.; Pearson, R.D.; Peshu, N.; Phyo, A.P.; Plowe, C.V.; Price, R.N.; Pukrittayakamee, S.; Randrianarivelojosia, M.; Rayner, J.C.; Ringwald, P.; Rockett, K.A.; Rowlands, K.; Ruiz, L.; Saunders, D.; Shayo, A.; Siba, P.; Simpson, V.J.; Stalker, J.; Su, X.; Sutherland, C.; Takala-Harrison, S.; Tavul, L.; Thathy, V.; Tshefu, A.; Verra, F.; Vinetz, J.; Wellems, T.E.; Wendler, J.; White, N.J.; Wright, I.; Yavo, W.; Ye, H.MalariaGEN is a data-sharing network that enables groups around the world to work together on the genomic epidemiology of malaria. Here we describe a new release of curated genome variation data on 7,000 Plasmodium falciparum samples from MalariaGEN partner studies in 28 malaria-endemic countries. High-quality genotype calls on 3 million single nucleotide polymorphisms (SNPs) and short indels were produced using a standardised analysis pipeline. Copy number variants associated with drug resistance and structural variants that cause failure of rapid diagnostic tests were also analysed. Almost all samples showed genetic evidence of resistance to at least one antimalarial drug, and some samples from Southeast Asia carried markers of resistance to six commonly-used drugs. Genes expressed during the mosquito stage of the parasite life-cycle are prominent among loci that show strong geographic differentiation. By continuing to enlarge this open data resource we aim to facilitate research into the evolutionary processes affecting malaria control and to accelerate development of the surveillance toolkit required for malaria elimination.Item Targeted Next Generation Sequencing for malaria research in Africa: current status and outlook(Malaria Journal, 2019-09-23) Ghansah, A.; Kamau, E.; Amambua‑Ngwa, A.; Ishengoma, D.S.; Maiga‑Ascofare, O.; Amenga‑Etego, L.; Deme, A.; Yavo, W.; Randrianarivelojosia, M.; Ochola‑Oyier, L.I.; Helegbe, G.K.; Bailey, J.; Alifrangis, M.; Djimde, A.Targeted Next Generation Sequencing (TNGS) is an efficient and economical Next Generation Sequencing (NGS) platform and the preferred choice when specific genomic regions are of interest. So far, only institutions located in middle and high-income countries have developed and implemented the technology, however, the efficiency and cost savings, as opposed to more traditional sequencing methodologies (e.g. Sanger sequencing) make the approach potentially well suited for resource-constrained regions as well. In April 2018, scientists from the Plasmodium Diversity Network Africa (PDNA) and collaborators met during the 7th Pan African Multilateral Initiative of Malaria (MIM) conference held in Dakar, Senegal to explore the feasibility of applying TNGS to genetic studies and malaria surveillance in Africa. The group of scientists reviewed the current experience with TNGS platforms in sub-Saharan Africa (SSA) and identified potential roles the technology might play to accelerate malaria research, scientific discoveries and improved public health in SSA. Research funding, infrastructure and human resources were highlighted as challenges that will have to be mitigated to enable African scientists to drive the implementation of TNGS in SSA. Current roles of important stakeholders and strategies to strengthen existing networks to effectively harness this powerful technology for malaria research of public health importance were discussed