Browsing by Author "Doumbo, O.K."
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Item A Research Agenda to Underpin Malaria Eradication(PLoS Medicine, 2011-01-25) Alonso, P.L.; Brown, G.; Arevalo-Herrera, M.; Binka, F.; Chitnis, C.; Collins, F.; Doumbo, O.K.; Greenwood, B.; Hall, B.F.; Levine, M.M.; Mendis, K.; Newman, R.D.; Plowe, C.V.; Rodrı´guez, M.H.; Sinden, R.; Slutsker, L.; Tanner, M.The interruption of malaria transmission worldwide is one of the greatest challenges for international health and development communities. The current expert view suggests that, by aggressively scaling up control with currently available tools and strategies, much greater gains could be achieved against malaria, including elimination from a number of countries and regions; however, even with maximal effort we will fall short of global eradication. The Malaria Eradication Research Agenda (malERA) complements the current research agenda—primarily directed towards reducing morbidity and mortality—with one that aims to identify key knowledge gaps and define the strategies and tools that will result in reducing the basic reproduction rate to less than 1, with the ultimate aim of eradication of the parasite from the human population. Sustained commitment from local communities, civil society, policy leaders, and the scientific community, together with a massive effort to build a strong base of researchers from the endemic areas will be critical factors in the success of this new agenda.Item A shared Asian origin of the triple-mutant dhfr allele in Plasmodium falciparum from sites across Africa(Journal of Infectious Diseases 196(1):165-72, 2007) Maïga, O.; Djimdé, A.A.; Hubert, V.; Renard, E.; Aubouy, A.; Kironde, F.; Nsimba, B.; Koram, K.A.; Doumbo, O.K.; Le Bras, J.; Clain, J.Usefulness of sulfadoxine-pyrimethamine as first-line therapy for uncomplicated Plasmodium falciparum malaria and intermittent preventive treatment in pregnancy throughout sub-Saharan Africa is compromised by the spread of dhfr alleles associated with pyrimethamine resistance. A predominant haplotype associated with the N51I+C59R+S108N triple-mutant dhfr allele has been reported recently in 4 African countries. A more comprehensive picture of the evolution of this mutant allele in Africa is lacking. METHODS: Seventy-five P. falciparum isolates carrying the wild-type dhfr allele and 204 carrying the triple-mutant dhfr allele from 11 African countries were selected. The genetic diversity of the chromosomes bearing these alleles was analyzed with 4 microsatellite markers closely linked to the dhfr gene. RESULTS: Seventy-three different 4-locus haplotypes carrying the wild-type dhfr allele were found. By contrast, 175 (85%) of 204 isolates carrying the triple-mutant dhfr allele shared a unique haplotype, identical to the one identified in Thailand. For the remaining triple-mutant isolates and one isolate with the quadruple-mutant dhfr allele N51I+C59R+S108N+I164L), haplotypes were closely related to the predominant haplotype by mutation or recombination. CONCLUSIONS: Migration of parasites carrying an ancestral triple-mutant dhfr allele drives the spread of dhfr alleles associated with pyrimethamine resistance throughout West and Central Africa.Item A shared Asian origin of the triple-mutant DHFR allele in plasmodium falciparum from sites across Africa.(2007-07-01) Maiga, O.; Djimde, A.A.; Hubert, V.; Renard, E.; Aubouy, A.; Kironde, F.; Nsimba, B.; Koram, K.A.; Doumbo, O.K.; Le Bras, J.; Clain, J.Background. Usefulness of sulfadoxine-pyrimethamine as first-line therapy for uncomplicated Plasmodium falciparum malaria and intermittent preventive treatment in pregnancy throughout sub-Saharan Africa is compromised by the spread of dhfr alleles associated with pyrimethamine resistance. A predominant haplotype associated with the N51I+C59R+S108N triple-mutant dhfr allele has been reported recently in 4 African countries. A more comprehensive picture of the evolution of this mutant allele in Africa is lacking. Methods. Seventy-five P. falciparum isolates carrying the wild-type dhfr allele and 204 carrying the triple-mutant dhfr allele from 11 African countries were selected. The genetic diversity of the chromosomes bearing these alleles was analyzed with 4 microsatellite markers closely linked to the dhfr gene. Results. Seventy-three different 4-locus haplotypes carrying the wild-type dhfr allele were found. By contrast, 175 (85%) of 204 isolates carrying the triple-mutant dhfr allele shared a unique haplotype, identical to the one identified in Thailand. For the remaining triple-mutant isolates and one isolate with the quadruple-mutant dhfr allele (N51I+C59R+S108N+I164L), haplotypes were closely related to the predominant haplotype by mutation or recombination. Conclusions. Migration of parasites carrying an ancestral triple-mutant dhfr allele drives the spread of dhfr alleles associated with pyrimethamine resistance throughout West and Central Africa. © 2007 by the Infectious Diseases Society of America. All rights reserved.