Efficacy of antimalarial treatment in Guinea: in vivo study of two artemisinin combination therapies in Dabola and molecular markers of resistance to sulphadoxine-pyrimethamine in N'Zérékoré

BACKGROUND: In the last five years, countries have been faced with changing their malaria treatment policy to an artemisinin-based combination therapy (ACT), many with no national data on which to base their decision. This is particularly true for a number of West African countries, including Guinea, where these studies were performed. Two studies were conducted in 2004/2005 in programmes supported by Medecins Sans Frontieres, when chloroquine was still national policy, but artesunate (AS)/sulphadoxine-pyrimethamine (SP) had been used in refugee camps for two years. METHODS: In Dabola (central Guinea), 220 children aged 6-59 months with falciparum malaria were randomized to receive either AS/amodiaquine (AQ) or AS/SP. In vivo efficacy was assessed following the 2003 World Health Organization guidelines. In a refugee camp in Laine (south of Guinea), where an in vivo study was not feasible due to the unstable context, a molecular genotyping study in 160 patients assessed the prevalence of mutations in the dihydrofolate reductase (dhfr) (codons 108, 51, 59) and dihydropteroate synthase (dhps) (codons 436, 437, 540) genes of Plasmodium falciparum, which have been associated with resistance to pyrimethamine and sulphadoxine, respectively. RESULTS: In Dabola, after 28 days of follow-up, Polymerase Chain Reaction (PCR)-adjusted failure rates were 1.0% (95%CI 0-5.3) for AS/AQ and 1.0% (95%CI 0-5.5) for AS/SP. In the refugee camp in Laine, the molecular genotyping study found three dhfr mutations in 85.6% (95%CI 79.2-90.7) patients and quintuple dhfr/dhps mutations in 9.6% (95%CI 5.2-15.9). CONCLUSION: Both AS/AQ and AS/SP are highly efficacious in Dabola, whereas there is molecular evidence of established SP resistance in Laine. This supports the choice of the national programme of Guinea to adopt AS/AQ as first line antimalarial treatment. The results highlight the difficulties faced by control programmes, which have gone through the upheaval of implementing ACTs, but cannot predict how long their therapeutic life will be, especially in countries which have chosen drugs also available as monotherapies

Cassava whitefly, Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae), in sub-Saharan African farming landscapes: a review of the factors determining abundance

Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae) is a pest species complex that causes widespread damage to cassava, a staple food crop for millions of smallholder households in Sub-Saharan Africa. Species in the complex cause direct feeding damage to cassava and are the vectors of multiple plant viruses. Whilst significant work has gone into developing virus-resistant cassava cultivars, there has been little research effort aimed at understanding the ecology of these insect vectors. In this review we critically assess the knowledge base relating to factors that may lead to high population densities of Sub-Saharan African (SSA) Bemisia tabaci species in cassava production landscapes of East Africa. We focus first on empirical studies that have examined biotic or abiotic factors that may lead to high populations. We then identify knowledge gaps that need to be filled to deliver long-term sustainable solutions to manage both the vectors and the viruses that they transmit. We found that whilst many hypotheses have been put forward to explain the increases in abundance witnessed since the early 1990s, there are little available published data and these tend to have been collected in a piecemeal manner. The most critical knowledge gaps identified were: (i) understanding how cassava cultivars and alternative host plants impact B. tabaci population dynamics and its natural enemies; (ii) the impact of natural enemies in terms of reducing the frequency of outbreaks and (iii) the use and management of insecticides to delay or avoid the development of resistance. In addition, there are several fundamental methodologies that need to be developed and deployed in East Africa to address some of the more challenging knowledge gaps

Guide pratique des plantations d'arbres des forêts denses humides d'Afrique

In Africa, tree plantations are likely to be developed for several reasons: restoration of production capacities and services provided by natural forests, enhancement of agroforestry lands, easier harvesting of wood and non-wood forest products, etc. As exotic species only provide specific services, it is important to revitalize the planting of local species. This is the purpose of this guide, which focuses on species of dense rainforests, capitalizing on the results of past and recent trials in six African countries, and on the This is the purpose of this guide, which focuses on species of dense rainforests, capitalizing on the results of past and recent trials in six African countries, and mobilizing individual skills and knowledge. The book provides a practical approach to the various stages of a silvicultural program: seed collection and management, nursery construction and management, and plantation installation and management. An estimate of the costs and profitability of such plantations is also provided. Finally, the book describes in detail the silvicultural itinerary of 50 tree species of the African rainforests. This guide is intended for a wide audience: managers, forestry technicians and engineers, students and scientists interested in tropical silviculture

CINEMATIQUE D’UNE TABLE HYDRAULIQUE DE MANUTENTION

International audienceDans l’objectif de faire un calcul de « dimensionnement d’une table hydraulique de manutention » nous faisons d’abord une étude cinématique de la machine en vue de déterminer les conditions que doivent remplir les différents paramètres géométriques et cinématiques pour réaliser les différentes liaisons entre les éléments

La cohabitation du français et des langues nationales en République démocratique du Congo est-elle harmonieuse ?

La République démocratique du Congo est un pays plurilingue et pluriethnique. Chaque ethnie – on compte à l’heure actuelle plus de 450 ethnies –, possède pratiquement sa langue. Le français, une langue étrangère, cohabite avec ces dernières et, principalement, avec les quatre langues nationales. Cette cohabitation est-elle conflictuelle ou harmonieuse, en d’autres termes est-elle possible ? Le présent article se propose d’analyser les conditions qui sont susceptibles de permettre la convivial..

Congolese National Police Patrols in Mbujimayi and the bottom of ‘the coffee operation’ : explanatory factors and possible outcomes

Abstract onlyFrench version available in IDRC Digital Library: Les patrouilles de la police nationale congolaise a Mbujimayi et les dessous de "l’Operation Cafe" : facteurs explicatifs et issues possiblesThe protection of individual rights is an important pillar of any society. The Congolese constitution spells out clear duties for the country’s National Police: they are responsible for, in times of peace, the economic, social and cultural development of the country and to protect its citizens and their goods. Despite these lofty goals, however, abuse of power is a common experience among patrolling cops in Mbujimayi, and instead of protecting the public, public spaces have become securitized by the presence of armed police. Researcher offer policy recommendations to the Congolese government, including more attention paid to individual disposition in the recruitment process, and adequate and appropriate training. They also highlight the importance of transparency and of conceptualizing the police as separate from the army