Key traveller groups of relevance to spatial malaria transmission: a survey of movement patterns in four sub-Saharan African countries

Background: As malaria prevalence declines in many parts of the world due to widescale control efforts and as drug-resistant parasites begin to emerge, a quantitative understanding of human movement is becoming increasingly relevant to malaria control. However, despite its importance, significant knowledge gaps remain regarding human movement, particularly in sub-Saharan Africa. Methods: A quantitative survey of human movement patterns was conducted in four countries in sub-Saharan Africa: Mali, Burkina Faso, Zambia, and Tanzania, with three to five survey locations chosen in each country. Questions were included on demographic and trip details, malaria risk behaviour, children accompanying travellers, and mobile phone usage to enable phone signal data to be better correlated with movement. A total of 4352 individuals were interviewed and 6411 trips recorded. Results: A cluster analysis of trips highlighted two distinct traveller groups of relevance to malaria transmission: women travelling with children (in all four countries) and youth workers (in Mali). Women travelling with children were more likely to travel to areas of relatively high malaria prevalence in Mali (OR = 4.46, 95 % CI = 3.42–5.83), Burkina Faso (OR = 1.58, 95 % CI = 1.23–1.58), Zambia (OR = 1.50, 95 % CI = 1.20–1.89), and Tanzania (OR = 2.28, 95 % CI = 1.71–3.05) compared to other travellers. They were also more likely to own bed nets in Burkina Faso (OR = 1.77, 95 % CI = 1.25–2.53) and Zambia (OR = 1.74, 95 % CI = 1.34 2.27), and less likely to own a mobile phone in Mali (OR = 0.50, 95 % CI = 0.39–0.65), Burkina Faso (OR = 0.39, 95 % CI = 0.30–0.52), and Zambia (OR = 0.60, 95 % CI = 0.47–0.76). Malian youth workers were more likely to travel to areas of relatively high malaria prevalence (OR = 23, 95 % CI = 17–31) and for longer durations (mean of 70 days cf 21 days, p < 0.001) compared to other travellers. Conclusions: Women travelling with children were a remarkably consistent traveller group across all four countries surveyed. They are expected to contribute greatly towards spatial malaria transmission because the children they travel with tend to have high parasite prevalence. Youth workers were a significant traveller group in Mali and are expected to contribute greatly to spatial malaria transmission because their movements correlate with seasonal rains and hence peak mosquito densities. Interventions aimed at interrupting spatial transmission of parasites should consider these traveller groups

Accroissement et diversification de l'offre de produits laitiers au Sénégal : la bataille industrielle du lait en poudre à Dakar et des minilaiteries à la conquête des marchés des villes secondaires

Les travaux d'analyse de l'évolution de l'offre de produits laitiers au Sénégal, entre 2000 et 2005, ont mis en évidence un certain cloisonnement géographique des marchés avec une tendance à la diversification de l'offre de produits sur le marché de Dakar. Cette évolution est liée à la croissance des importations de lait en poudre et au développement d'un tissu d'industries, et de petites et moyennes entreprises / industries. La bataille commerciale que se livrent les importateurs et transformateurs industriels révèle la croissance de la demande et l'enjeu économique du marché dakarois. La filière locale, caractérisée par un accroissement du nombre de petites unités de transformation, se développe surtout dans les régions. Cependant, le dynamisme de ce secteur échappe aux décideurs politiques à Dakar du fait du confinement des minilaiteries sur les marchés des villes secondaires où elles sont implantées. L'Etat a privilégié la couverture des besoins des consommateurs dakarois avec des tarifs douaniers particulièrement bas pour la poudre de lait transformée qui bénéficie, de plus, de subventions dans les pays producteurs. Ses interventions sur la filière locale, basées sur l'intensification (insémination artificielle), n'ont pas permis de lever les multiples contraintes (santé animale, alimentation, eau, gestion de la qualité, collecte du lait de brousse...). Il semble dès lors nécessaire dans l'élaboration des politiques laitières d'examiner la filière de manière plus globale et de favoriser une concertation avec l'ensemble des acteurs des deux sous-filières pour accroître l'impact des décisions politiques, notamment en termes de sécurité alimentaire et de lutte contre la pauvreté en milieu rural. (Résumé d'auteur

Development of frozen-fried yam slices: Optimization of the processing conditions

The research performed on yam processing mainly concerns the production of crisps and flour. However, its transformation into deep-frozen French fries does not necessitate any other equipment than those used for potatoes. The industrial process of production of frozen French fries traditionally includes a pre-frying step. These steps contribute to the development of color and crispness, and the oil partially absorbed inhibits dehydration during the freezing step. The aim of this study was tooptimize frying conditions of deep-frozen fried yam (Dioscorea cayenensis var Kponan) slices. The effect of pre-frying time and temperature, final frying time and temperature on the oil uptake, texture, dry matter and colour of the fried yam slices has been studied. Frying conditions optimized with Box-Behnken experimental design were short pre-frying and frying conditions at high temperature characterized by prefryingtemperature at 157-170°C during 5-9s and frying temperature at 181-188°C for 2min 15s-2min 30s; or long pre-frying and frying conditions at low temperature characterized by pre-frying temperature at 150-158°C during 10-15s and frying temperature 170-177°C for 3-3min 15s. An adiabatic system was also developed by means of an insulator in which the core temperature of fried yam slices can be maintained constant at about 55°C after 15min of cooling, facilitating texture measurements at constant temperature. The present results may help in choosing the yam slices frying condition to be applied in order to achieve the desirable fried yamslices quality, required for protection against certain diseases like obesity. These models may also provide guidance as to how to control these quality parameters by altering four key environmental factors, pre-frying temperature and time and, final frying temperature and time. This process can also be commercialized and does not necessitate any other cost for equipment than those used for potatoes French fries and might be an interesting way of added value processing for this highly perishable yamtuber

Synthesis and anthelmintic activity of some hybrid Benzimidazolyl-chalcone derivatives

Purpose: To synthesize hybrid benzimidazolyl-chalcone derivatives, evaluate their anthelmintic activity, and establish some structural elements which could lead to induction and enhancement of this activity.Methods: A series of 1-(1H-benzimidazol-2-yl)-3-aryl-2-propen-1-one compounds (6a-z) was synthesized by condensation reaction of 2-acetylbenzimidazole with aryl and heteroaryl aldehyde derivatives. The physicochemical characterization of these benzimidazolyl-chalcones was carried out by nuclear magnetic resonance spectroscopy (1H and 13C NMR) and mass spectroscopy (MS). All compounds were screened in vitro for their nematicidal activity against Haemonchus contortus in larval development assay. The anthelmintic activities obtained were compared with those of anthelmintic reference drugs (fenbendazole and ivermectin); 1,3-diphenyl-2-propen-1-one also used as reference for chalcone.Results: Compounds 6a, 6g, 6w and 6y showed good nematicidal activity (LC100) at 0.002 and 0.0092 &mu;g/ml. The activity of these four benzimidazolyl-chalcones is nearly equal to that of fenbendazole. It is also interesting to know that these compounds have anti-haemonchus activity which is equal or more efficient than ivermectin. Four other compounds (6d, 6h, 6o and 6t) possess interesting anthelmintic activities at 0.68 and 0.16 &mu;g/ml.Conclusion: Preliminary structure-activity relationship studies revealed that arylpropenone group in position 2 of the benzimidazole ring can be considered as new pharmacophore for nematicidal activity.Keywords: Benzimidazole, Chalcone, Anthelmintic activity, Haemonchus contortu

Feed the Future Mali: Scaling up technological and institutional livestock innovations

United States Agency for International Developmen

Vivre et penser le sida en Afrique = Experiencing and understanding AIDS in Africa

Dans un contraste de plus en plus accusé entre le Nord et le Sud, qui met en relief deux sortes de sida - l'un traitable et en voie de stabilisation, l'autre incurable et en voie d'expansion -, des chercheurs francophones et anglophones en sciences sociales tentent de répondre ici à une double exigence. Travaillant en Afrique subsaharienne sur une épidémie qui représente 70% des cas mondiaux, ils entendent contribuer à rendre intelligible les programmes d'information et de prévention. Se démarquant nettement des stéréotypes par trop répandus d'un continent où les cultures immémoriables et une certaine "promiscuité sexuelle" seraient le terreau de l'épidémie, leurs diverses approches mettent l'accent sur les contextes de vulnérabilité économique, sociale et politique des populations africaines et sur la façon dont celles-ci interprètent l'épidémie au regard de leurs conditions concrètes d'existence et des multiples difficultés et tensions auxquelles elles sont confrontées. Non réductible à un problème sanitaire, le "phénomène sida" appelle des politiques publiques qui ne se contentent pas de délivrer des messages de prévention sur le préservatif ou la fidélité, mais qui diversifient leurs interventions en fonction des situations sociales et des significations auxquelles le sida a déjà donné lieu. Mais cette démarche analytique des chercheurs en sciences sociales est prolongée d'un point de vue plus critique : parler de politiques publiques, c'est d'abord, pour eux, refuser que perdure en Afrique l'image d'un sida incurable et que ne soient pas transférés les progrès thérapeutiques qui ont considérablement modifié cette image au Nord. C'est par conséquent au prix d'une mobilisation de la communauté internationale que les Etats africains seront amenés eux-mêmes à manifester une plus grande volonté politique et à faire en sorte que le sida devienne un sujet central du débat public. (Résumé d'auteur

Dynamics of multiple insecticide resistance in the malaria vector Anopheles gambiae in a rice growing area in South-Western Burkina Faso

<p>Abstract</p> <p>Background</p> <p>Insecticide resistance of the main malaria vector, <it>Anopheles gambiae</it>, has been reported in south-western Burkina Faso, West Africa. Cross-resistance to DDT and pyrethroids was conferred by alterations at site of action in the sodium channel, the Leu-Phe <it>kdr </it>mutation; resistance to organophosphates and carbamates resulted from a single point mutation in the oxyanion hole of the acetylcholinesterase enzyme designed as <it>ace-1</it>^<it>R</it>.</p> <p>Methods</p> <p>An entomological survey was carried out during the rainy season of 2005 at Vallée du Kou, a rice growing area in south-western Burkina Faso. At the Vallée du Kou, both insecticide resistance mechanisms have been previously described in the M and S molecular forms of <it>An. gambiae</it>. This survey aimed i) to update the temporal dynamics and the circumsporozoite infection rate of the two molecular forms M and S of <it>An. gambiae </it>ii) to update the frequency of the Leu-Phe <it>kdr </it>mutation within these forms and finally iii) to investigate the occurrence of the <it>ace-1</it>^{<it>R </it>}mutation.</p> <p>Mosquitoes collected by indoor residual collection and by human landing catches were counted and morphologically identified. Species and molecular forms of <it>An. gambiae</it>, <it>ace-1</it>^{<it>R </it>}and Leu-Phe <it>kdr </it>mutations were determined using PCR techniques. The presence of the circumsporozoite protein of <it>Plasmodium falciparum </it>was determined using ELISA.</p> <p>Results</p> <p><it>Anopheles gambiae </it>populations were dominated by the M form. However the S form occurred in relative important proportion towards the end of the rainy season with a maximum peak in October at 51%. Sporozoite rates were similar in both forms. The frequency of the Leu-Phe <it>kdr </it>mutation in the S form reached a fixation level while it is still spreading in the M form. Furthermore, the <it>ace</it>-<it>1</it>^{<it>R </it>}mutation prevailed predominately in the S form and has just started spreading in the M form. The two mutations occurred concomitantly both in M and S populations.</p> <p>Conclusion</p> <p>These results showed that the Vallée du Kou, a rice growing area formerly occupied mainly by M susceptible populations, is progressively colonized by S resistant populations living in sympatry with the former. As a result, the distribution pattern of insecticide resistance mutations shows the occurrence of both resistance mechanisms concomitantly in the same populations. The impact of multiple resistance mechanisms in M and S populations of <it>An. gambiae </it>on vector control measures against malaria transmission, such as insecticide-treated nets (ITNs) and indoor residual spraying (IRS), in this area is discussed.</p

Etudes comparatives sur les bovins N'Dama de haute Casamance pour évaluer leur trypanotolérance en fonction de la couleur de leur robe

Les techniques les plus modernes pour la diagnose des trypanosomoses: (technique de Woo, examen sur lames, immunofluorescence, test micro ELISA, test immunospécifique par comptage enzymatique) ont été utilisées sur du bétail N'Dama de Haute-Casamance, au Sénégal, pour vérifier si la qualité de leur trypanotolérance est en relation avec la couleur de leur robe, compte tenu de la réputation qu'ont les N'Dama de couleur fauve d'être les plus résistants. Des observations faites, qui ont porté sur 210 sujets pour les examens hématologiques et parasitaires, et sur 260 pour les études de sérologie, il résulte que les N'Dama de couleur fauve ne sont ni plus ni moins trypanotolérants que ceux à robe blanche, noire ou pie, ces derniers ayant souvent, par ailleurs, une remarquable conformation d'animaux de trait ou de boucherie. Il n'y a donc apparemment aucune raison qui justifie le choix de la seule couleur fauve comme critère de race plus résistante aux trypanosomoses. Les auteurs préconisent donc l'abandon de ce critère racial, avec le bénéfice a en attendre au plan de la sélection et de la diffusion d'animaux de cette rac