Combining indoor residual spraying with chlorfenapyr and long-lasting insecticidal bed nets for improved control of pyrethroid-resistant Anopheles gambiae: an experimental hut trial in Benin.

BACKGROUND: Neither indoor residual spraying (IRS) nor long-lasting insecticidal nets (LLINs) are able to fully interrupt transmission in holoendemic Africa as single interventions. The combining of IRS and LLINs presents an opportunity for improved control and management of pyrethroid resistance through the simultaneous presentation of unrelated insecticides. METHOD: Chlorfenapyr IRS and a pyrethroid-impregnated polyester LLIN (WHO approved) were tested separately and together in experimental huts in southern Benin against pyrethroid resistant Anopheles gambiae and Culex quinquefasciatus. The bed nets were deliberately holed with either six or 80 holes to examine the effect of increasing wear and tear on protectiveness. Anopheles gambiae were genotyped for the kdr gene to assess the combination's potential to prevent the selection of pyrethroid resistance. RESULTS: The frequency of kdr was 84%. The overall mortality rates of An. gambiae were 37% and 49% with the six-hole and 80-hole LLINs, respectively, and reached 57% with chlorfenapyr IRS. Overall mortality rates were significantly higher with the combination treatments (82-83%) than with the LLIN or IRS individual treatments. Blood feeding (mosquito biting) rates were lowest with the 6-hole LLIN (12%), intermediate with the 80-hole LLIN (32%) and highest with untreated nets (56% with the 6-hole and 54% with the 80-hole nets). Blood feeding (biting) rates and repellency of mosquitoes with the combination of LLIN and chlorfenapyr IRS showed significant improvement compared to the IRS treatment but did not differ from the LLIN treatments indicating that the LLINs were the primary agents of personal protection. The combination killed significantly higher proportions of Cx. quinquefasciatus (51%, 41%) than the LLIN (15%, 13%) or IRS (32%) treatments. CONCLUSION: The chlorfenapyr IRS component was largely responsible for controlling pyrethroid-resistant mosquitoes and the LLIN component was largely responsible for blood feeding inhibition and personal protection. Together, the combination shows potential to provide additional levels of transmission control and personal protection against pyrethroid-resistant mosquitoes, thereby justifying the additional resources required. Chlorfenapyr has potential to manage pyrethroid resistance in the context of an expanding LLIN/IRS strategy

Physico- Chemical characteristics of compost (Cotonou, Benin, West Africa)

This work was led the town of Cotonou in Benin and particularly on the vegetable garden site of Houéyiho. It involved the valorization of the waste of this site by proceeding the aerobic composting of the biodegradable fraction of municipal solid waste collected in the markets. This consists among other rotten fruits of various plant debris and garbage obtained by initial sorting. After three months of biological decomposition, 48,531.78 kg of biodegradable waste was composted with a yield of 40,443.33 kg of fresh compost or approximately 83.33% compost. The moisture content of the biodegradable fraction is 65%. The physico-chemical characteristics of compost produced are as follow: 12.7594 ± 0.1006 mg / kg of heavy metals, the C / N ratio is 13% and the rate of total phosphorus is 0.34% and 61.18 meq/100 g of Dry Weight exchangeable bases. The humus of our compost has a high capacity of cationic exchange (CCE) and fixed mineral nutrient ions such as K+ and Ca2+ and phosphate in order to make them available for plant growth and development and proving the poverty of the soil of this site and their increased need of organic amendment.Keywords: Cotonou; biodegradable waste; compost; physico- chemical characteristics; poor soi

Use of the HEC RAS model for the analysis of exceptional floods in the Ouémé basin

The Ouémé River basin extends over almost half of Benin's territory, entirely located in a humid tropical climate. This river system includes a deltaic zone (delta of the Ouémé) known for its high agricultural potential and thus subject to a socio-economic development agenda. The Ouémé delta is facing recurrent floods that maintain rural agricultural population into a retrograding crisis with significant damages such as losses of properties. The objective of this study is to improve decision-making in the Ouémé basin through the simulation of exceptional floods using the HEC-RAS model. The HEC RAS model is a conceptual model, which works through mathematical and physical formulas to implement environmental phenomena for forecasting, understanding and analysis purposes. The model inputs used are basin GIS data, hydro-meteorological data, characteristics of existing hydraulic structures, etc. The targeted outputs include 1D/2D/3D view plans with support of satellite images, tables, graphs and curves. It is worth mentioning that the model provides outputs compatible with other tools, such as civil engineering (Civil 3D, Revit, Infraworks, etc.) and GIS, that help to expand the valorization fields. The implementation of the model in the Ouémé basin has made it possible to note: (i) that the recurring effect of losses and damages is justified by the settlement of the population on the river banks; (ii) that there is an important agricultural production in areas of high flood risk; (iii) that depending on the occurrence of the phenomenon, the flooded extent and the height of submersion remains variable, and more important for extreme flooding; (iv) about 12.07 % occurrence of river flood against 13.24 % for flash flood at a return period of 30 years. Moreover, it is very relevant to note that most of flood waters converge to the western part of the basin (an area with a low risk of flooding, stretched over 63.68 km2) and to the eastern part around the Damè-Wogon depression (an area at high risk of flooding, stretched over 10.49 km2).</p

Predicting the Current and Future Potential Distributions of Lymphatic Filariasis in Africa Using Maximum Entropy Ecological Niche Modelling

Modelling the spatial distributions of human parasite species is crucial to understanding the environmental determinants of infection as well as for guiding the planning of control programmes. Here, we use ecological niche modelling to map the current potential distribution of the macroparasitic disease, lymphatic filariasis (LF), in Africa, and to estimate how future changes in climate and population could affect its spread and burden across the continent. We used 508 community-specific infection presence data collated from the published literature in conjunction with five predictive environmental/climatic and demographic variables, and a maximum entropy niche modelling method to construct the first ecological niche maps describing potential distribution and burden of LF in Africa. We also ran the best-fit model against climate projections made by the HADCM3 and CCCMA models for 2050 under A2a and B2a scenarios to simulate the likely distribution of LF under future climate and population changes. We predict a broad geographic distribution of LF in Africa extending from the west to the east across the middle region of the continent, with high probabilities of occurrence in the Western Africa compared to large areas of medium probability interspersed with smaller areas of high probability in Central and Eastern Africa and in Madagascar. We uncovered complex relationships between predictor ecological niche variables and the probability of LF occurrence. We show for the first time that predicted climate change and population growth will expand both the range and risk of LF infection (and ultimately disease) in an endemic region. We estimate that populations at risk to LF may range from 543 and 804 million currently, and that this could rise to between 1.65 to 1.86 billion in the future depending on the climate scenario used and thresholds applied to signify infection presence

SINE RNA Induces Severe Developmental Defects in Arabidopsis thaliana and Interacts with HYL1 (DRB1), a Key Member of the DCL1 Complex

The proper temporal and spatial expression of genes during plant development is governed, in part, by the regulatory activities of various types of small RNAs produced by the different RNAi pathways. Here we report that transgenic Arabidopsis plants constitutively expressing the rapeseed SB1 SINE retroposon exhibit developmental defects resembling those observed in some RNAi mutants. We show that SB1 RNA interacts with HYL1 (DRB1), a double-stranded RNA-binding protein (dsRBP) that associates with the Dicer homologue DCL1 to produce microRNAs. RNase V1 protection assays mapped the binding site of HYL1 to a SB1 region that mimics the hairpin structure of microRNA precursors. We also show that HYL1, upon binding to RNA substrates, induces conformational changes that force single-stranded RNA regions to adopt a structured helix-like conformation. Xenopus laevis ADAR1, but not Arabidopsis DRB4, binds SB1 RNA in the same region as HYL1, suggesting that SINE RNAs bind only a subset of dsRBPs. Consistently, DCL4-DRB4-dependent miRNA accumulation was unchanged in SB1 transgenic Arabidopsis, whereas DCL1-HYL1-dependent miRNA and DCL1-HYL1-DCL4-DRB4-dependent tasiRNA accumulation was decreased. We propose that SINE RNA can modulate the activity of the RNAi pathways in plants and possibly in other eukaryotes

Sinusites maxillaires aiguës : Aspects epidemiologique, diagnostique et therapeutique (etude prospective a propos de 50 cas)

Introduction and objectives: The acute maxillary sinusitis represents 10-50% of sinuated complaints. Its development can be full of complications. The bibliography on this pathology is poor in Togo. In this situation it appeared to us necessary to carry out a prospective study on its epidemiological, diagnostic and therapeutic aspects in order to complete the local and regional literature on this subject.Methodology: This is a prospective study carried out on 50 patients over a period of 12 months in the ENT Department of the CHU Campus de Lomé.Results: The average age of our patients was 36.6 years (10-60 years). There was no gender predominance. The predisposing factors were mainly allergic (38%) and dental (14%). Headache(27.01%), nasal obstruction (23.56%), rhinorrhoea (13.79%) and insomnia (12.64%) were the principal reasons for consultation. The physical examination showed the hypertrophia of the inferior nasal concha (45.57%), the congestion of the nasal mucosa (30.38%) and the presence of pus in the middle meatus (24.05%). The seat was bilateral in 68% cases. The cephalosporins (46%) and the macrolides (34%) were the most widely used for a minimum period of 10 days. The recovery rate was 94%.Conclusion: The diagnosis of the acute maxillary sinusitis is clinical. An X-ray will be needed to find out what is favouring the local cause in the face of therapeutic failures. The cephalosporins or theassociation of amoxicillin-clavulanic acid used for a minimum period of 10 days allows to obtain a recovery rate more than 90%.Introduction et objectifs: La sinusite maxillaire aigue représente 10 à 50% des affections sinusiennes. Son évolution peut être émaillée de complications. La bibliographie sur cette pathologie est pauvre auTogo. Il nous a paru alors nécessaire de mener une étude prospective sur ses aspects épidémiologique, diagnostique et thérapeutique afin de compléter la littérature locale et régionale.Méthodologie : Il s’agi d’une étude prospective menée sur une période de 12 mois dans le serviced’ORL du CHU Campus de Lomé sur 50 patients.Résultats : L’âge moyen de nos patients était de 36,66 ans (10 à 60 ans). Il n’y avait pas de prédominance de sexe. Les facteurs favorisants étaient essentiellement allergiques (38%) et dentaire (14%). Céphalée (27,01%), obstruction nasale (23,56%), rhinorrhée (13,79%) et insomnie (12,64%) étaient les principaux motifs de consultations. L’examen physique a noté une hypertrophie du cornet inférieur (45,57%), une congestion de la muqueuse nasale (30,38%) et une présence de pus dans le méat moyen (24,05%). Le siège était bilatéral dans 68%. Les céphalosporines (46%) et les macrolides (34%)étaient les plus utilisés pendant une durée minimale de 10 jours. Le taux de guérison était de 94%.Conclusion : Le diagnostic de sinusite maxillaire aiguë est clinique. La radiographie sera demandée devant les échecs thérapeutiques à la recherche d’une cause locale favorisante. Les céphalosporines oul’association amoxicilline-acide clavulanique utilisées pendant une durée minimales de 10 jours permettent d’obtenir un taux de guérison dans plus de 90%