Role of Anopheles (Cellia) rufipes (Gough, 1910) and other local anophelines in human malaria transmission in the northern savannah of Cameroon: a crosssectional survey

Background As part of a study to determine the impact of insecticide resistance on the effectiveness of longlasting insecticide treated nets (LLINs) in the north of Cameroon, the unexpectedly high density and anthropophilic behaviour of Anopheles rufipes lead us to investigate this species bionomics and role in human malaria parasite transmission. Methods For four consecutive years (2011–2014), annual cross-sectional sampling of adult mosquitoes was conducted during the peak malaria season (September-October) in three health districts in northern Cameroon. Mosquitoes sampled by human landing catch and pyrethrum spray catch methods were morphologically identified, their ovaries dissected for parity determination and Anopheles gambiae siblings were identified by molecular assay. Infection with P. falciparum and blood meal source in residual fauna of indoor resting anopheline mosquitoes were determined by enzyme-linked-immunosorbent assays. Results Anopheles gambiae (sensu lato) (s.l.) comprised 18.4% of mosquitoes collected with An. arabiensis representing 66.27% of the sibling species. The proportion of An. rufipes (2.7%) collected was high with a humanbiting rate ranging between 0.441 and 11.083 bites/person/night (b/p/n) and an anthropophagic rate of 15.36%. Although overall the members of An. gambiae complex were responsible for most of the transmission with entomological inoculation rates (EIR) reaching 1.221 infective bites/person/night (ib/p/n), An. arabiensis and An.coluzzii were the most implicated. The roles of An. funestus, An. pharoensis and An. paludis were minor. Plasmodium falciparum circumsporozoite protein rate in Anopheles rufipes varied from 0.6 to 5.7% with EIR values between 0.010 and 0.481 ib/p/n Conclusions The study highlights the epidemiological role of An. rufipes alongside the members of the An.gambiae complex, and several other sympatric species in human malaria transmission during the wet season in northern Cameroon. For the first time in Cameroon, An. rufipes has been shown to be an important local malaria vector, emphasising the need to review the malaria entomological profile across the country as pre-requisite to effective vector management strategies

Role of Anopheles (Cellia) rufipes (Gough, 1910) and other local anophelines in human malaria transmission in the northern savannah of Cameroon: a crosssectional survey

Background As part of a study to determine the impact of insecticide resistance on the effectiveness of longlasting insecticide treated nets (LLINs) in the north of Cameroon, the unexpectedly high density and anthropophilic behaviour of Anopheles rufipes lead us to investigate this species bionomics and role in human malaria parasite transmission. Methods For four consecutive years (2011–2014), annual cross-sectional sampling of adult mosquitoes was conducted during the peak malaria season (September-October) in three health districts in northern Cameroon. Mosquitoes sampled by human landing catch and pyrethrum spray catch methods were morphologically identified, their ovaries dissected for parity determination and Anopheles gambiae siblings were identified by molecular assay. Infection with P. falciparum and blood meal source in residual fauna of indoor resting anopheline mosquitoes were determined by enzyme-linked-immunosorbent assays. Results Anopheles gambiae (sensu lato) (s.l.) comprised 18.4% of mosquitoes collected with An. arabiensis representing 66.27% of the sibling species. The proportion of An. rufipes (2.7%) collected was high with a humanbiting rate ranging between 0.441 and 11.083 bites/person/night (b/p/n) and an anthropophagic rate of 15.36%. Although overall the members of An. gambiae complex were responsible for most of the transmission with entomological inoculation rates (EIR) reaching 1.221 infective bites/person/night (ib/p/n), An. arabiensis and An.coluzzii were the most implicated. The roles of An. funestus, An. pharoensis and An. paludis were minor. Plasmodium falciparum circumsporozoite protein rate in Anopheles rufipes varied from 0.6 to 5.7% with EIR values between 0.010 and 0.481 ib/p/n Conclusions The study highlights the epidemiological role of An. rufipes alongside the members of the An.gambiae complex, and several other sympatric species in human malaria transmission during the wet season in northern Cameroon. For the first time in Cameroon, An. rufipes has been shown to be an important local malaria vector, emphasising the need to review the malaria entomological profile across the country as pre-requisite to effective vector management strategies

Identification and Phenotype of MAIT Cells in Cattle and Their Response to Bacterial Infections

Mucosal-associated invariant T (MAIT) cells are a population of innate-like T cells that utilize a semi-invariant T cell receptor (TCR) α chain and are restricted by the highly conserved antigen presenting molecule MR1. MR1 presents microbial riboflavin biosynthesis derived metabolites produced by bacteria and fungi. Consistent with their ability to sense ligands derived from bacterial sources, MAIT cells have been associated with the immune response to a variety of bacterial infections, such as Mycobacterium spp., Salmonella spp. and Escherichia coli. To date, MAIT cells have been studied in humans, non-human primates and mice. However, they have only been putatively identified in cattle by PCR based methods; no phenotypic or functional analyses have been performed. Here, we identified a MAIT cell population in cattle utilizing MR1 tetramers and high-throughput TCR sequencing. Phenotypic analysis of cattle MAIT cells revealed features highly analogous to those of MAIT cells in humans and mice, including expression of an orthologous TRAV1-TRAJ33 TCR α chain, an effector memory phenotype irrespective of tissue localization, and expression of the transcription factors PLZF and EOMES. We determined the frequency of MAIT cells in peripheral blood and multiple tissues, finding that cattle MAIT cells are enriched in mucosal tissues as well as in the mesenteric lymph node. Cattle MAIT cells were responsive to stimulation by 5-OP-RU and riboflavin biosynthesis competent bacteria in vitro. Furthermore, MAIT cells in milk increased in frequency in cows with mastitis. Following challenge with virulent Mycobacterium bovis, a causative agent of bovine tuberculosis and a zoonosis, peripheral blood MAIT cells expressed higher levels of perforin. Thus, MAIT cells are implicated in the immune response to two major bacterial infections in cattle. These data suggest that MAIT cells are functionally highly conserved and that cattle are an excellent large animal model to study the role of MAIT cells in important zoonotic infections

Military maladaptation : counterinsurgency and the politics of failure

Tactical learning is critical to battlefield success, especially in a counterinsurgency. This article tests the existing model of military adaption against a ‘most-likely’ case: the British Army’s counterinsurgency in the Southern Cameroons (1960–61). Despite meeting all preconditions thought to enable adaptation – decentralization, leadership turnover, supportive leadership, poor organizational memory, feedback loops, and a clear threat – the British still failed to adapt. Archival evidence suggests politicians subverted bottom-up adaptation, because winning came at too high a price in terms of Britain’s broader strategic imperatives. Our finding identifies an important gap in the extant adaptation literature: it ignores politics.PostprintPeer reviewe

Le Bassin du Lac Tchad face aux nouvelles formes de menace : la difficile dynamique de réponse régionale dans la lutte contre le groupe terroriste islamiste Boko Haram

Boko Haram est un groupe terroriste dont l’épicentre se situe au nord du Nigéria. Ce groupe qui avait au départ comme activité la dénonciation des tares de la société nigériane a plongé dans actions de terrorisme à partir de 2009 suite à la répression militaire de l’armée nigériane. Face à la difficulté du Nigéria de contenir Boko Haram, ce groupe s’est régionalisé, faisant ainsi ressortir les problèmes de coopération sécuritaire régionale dans le Bassin du Lac Tchad et au-delà. Malgré l’application de ces mécanismes régionaux de sécurité, Boko Haram a continué ses activités avec un bilan lourd : plus de 30 000 morts en sept années de conflit armé, plus 1.5 million de réfugiés et déplacés, 4.2 millions de personnes en situation d’insécurité alimentaire et sanitaire. Ceci nous amène à qualifier Boko Haram comme étant un des groupes terroristes islamistes les plus féroces des temps contemporains. En s’appuyant sur des ressources documentaires, ce mémoire vise à expliquer pourquoi les mécanismes régionaux de sécurité n’ont pas permis d’endiguer la menace Boko Haram. Ma démonstration se base sur deux arguments : tout d’abord, l’absence de leadership dans la lutte contre Boko Haram, manifesté par l’attitude du Nigéria au niveau régional et le manque d’intérêt du Tchad, a causé une difficulté d’alliance régionale. Le second argument stipule que la multiplication des organisations régionales dans le Bassin du Lac Tchad a créé des difficultés de coordination entre elles et des problèmes de monopole institutionnel empêchant à ces organisations d’agir efficacement contre le groupe terroriste Boko Haram.Boko Haram is a terrorist group from northern Nigeria. This group promoting the application of Sharia in northern Nigeria, became a terrorist group in 2009 after military repression by the Nigerian state. With the inability of the Nigerian army to contain this terrorist threat, Boko Haram increased its activities around the Lake Chad Basin and beyond. During several years of Boko Haram's atrocities, one of the most important problems comes from the failure of regional security mechanisms to stem this group. Despite the implementation of these regional security mechanisms, Boko Haram remains a serious threat that has taken a heavy toll: more than 20,000 deaths in seven years of armed conflict, more than 1.5 million refugees and displaced persons, 4.2 million facing health problems and food insecurity. This leads us to consider Boko Haram one of the most ferocious Islamist terrorist groups in modern times. Using resources such as books, scientific articles, newspapers, governments and NGO reports and documents published by international organizations, this thesis seeks to explain why the regional security mechanisms failed to contain Boko Haram. I focus on two arguments: first, the lack of leadership in the fight against Boko Haram, manifested by Nigeria's regional attitude and the lack of interest of Chad, led to the failure of collective action against the Boko Haram phenomenon. Then, the second argument states that the multiplication of regional organizations in the Lake Chad Basin created difficulties of coordination between them and problems of institutional monopoly, preventing these organizations from acting effectively against the terrorist group Boko Haram

Les relations financières entre le Cameroun et la France et l'image de la France au Cameroun (1946-1956)

Atangana Martin René. Les relations financières entre le Cameroun et la France et l'image de la France au Cameroun (1946-1956). In: Matériaux pour l'histoire de notre temps, n°32-33, 1993. Colonisations en Afrique , sous la direction de René Girault . pp. 47-52

Plongement multilingue non supervisée basé sur le mapping monolingue pour la traduction automatique neuronale des langues faiblement dotées

Limited data resources are the current problem for neural machine translation of low resources languages. In this paper we propose to use multilingual embedding as a method of representing words as input to a neural machine translator. This approach is then compared to word representation approaches in monolingual context used in the literature for neural machine translation. The results with multilingual embedding on a dataset of 7187 pairs of French-Ewondo parallel verses of the bible are promising because they are better than those obtained with the representation approaches used so far. We obtained 8.77% of blue for the unsupervised multilingual embedding,5.34% for the semi-supervised version and finally 4.92% for the word embedding with the skipgram architecture.Les ressources de données limitées sont le problème actuel de la traduction automatique neuronale des langues à faibles ressources. Dans cet article, nous proposons d'utiliser le plongement multilingue comme méthode de représentation des mots en entrée d'un traducteur neuronal. Cette approche est ensuite comparée aux approches de représentation de mots en contexte monolingue utilisées dans la littérature pour la traduction automatique neuronale. Les résultats avec le plongement multilingue sur un jeu de données de 7187 paires de versets parallèles français-éwondo de la bible sont prometteurs car ils sont meilleurs que ceux obtenus avec les approches de représentation utilisées jusqu'à présent. Nous avons obtenu 8,77% de bleu pour le plongement multilingue non supervisé, 5,34% pour la version semi-supervisée et enfin 4,92% pour le plongement de mots avec l'architecture skipgram