Cellulites cervico-faciales graves, morbidité et mortalité: à propos de 150 cas au CHU Yalgado Ouédraogo au Burkina Faso / Severe cervico-facial cellulitis, morbidity and mortality: concerning 150 cases at CHU Yalgado Ouedraogo in Burkina Faso

Introduction : Les cellulites cervico-faciales graves sont des infections redoutables de par leur extension locorégionale et à distance mais aussi de par le pronostic vital qu'elles peuvent engager. L'objectif de cette étude était d'étudier la morbi-mortalité des cellulites cervico-faciales graves. Méthode : Il s'est agi d'une étude transversale descriptive concernant tous les patients admis du 1er Janvier 2008 au 31 Décembre 2017 dans le service de Stomatologie/ Chirurgie Maxillo-Faciale du Centre Hospitalier Universitaire /Yalgado Ouédraogo pour cellulite cervico-faciale grave. Les variables étudiées étaient sociodémographiques, cliniques, paracliniques, thérapeutiques et évolutives. L'analysées a été faite grâce au logiciel Epi-Info 7. Résultats : La fréquence hospitalière annuelle était de 15 cas avec une moyenne d'âge de 36,9 ans et une prédominance masculine. Les facteurs favorisants étaient surtout la prise d'anti-inflammatoire non stéroïdien en monothérapie (65,3%). La tuméfaction concernait la région sous mentale dans 85,3% des cas. Des signes de compressions des voies aérodigestives supérieures étaient notés dans 22% des cas. La tomodensitométrie avait noté une diffusion cranioencéphalique chez 5,3% des patients. Le traitement a été médico-chirurgical avec une évolution clinique favorable. Il existait une corrélation entre le décès et le siège de la lésion, le sexe et le recours au traitement traditionnel. Conclusion : Les cellulites graves sont une urgence médico-chirurgicale et leur prise en charge est complexe et pluridisciplinaire. La prévention et le diagnostic précoce peuvent contribuer à réduire la morbi-mortalité.

Intermediate tree cover can maximize groundwater recharge in the seasonally dry tropics.

Water scarcity contributes to the poverty of around one-third of the world's people. Despite many benefits, tree planting in dry regions is often discouraged by concerns that trees reduce water availability. Yet relevant studies from the tropics are scarce, and the impacts of intermediate tree cover remain unexplored. We developed and tested an optimum tree cover theory in which groundwater recharge is maximized at an intermediate tree density. Below this optimal tree density the benefits from any additional trees on water percolation exceed their extra water use, leading to increased groundwater recharge, while above the optimum the opposite occurs. Our results, based on groundwater budgets calibrated with measurements of drainage and transpiration in a cultivated woodland in West Africa, demonstrate that groundwater recharge was maximised at intermediate tree densities. In contrast to the prevailing view, we therefore find that moderate tree cover can increase groundwater recharge, and that tree planting and various tree management options can improve groundwater resources. We evaluate the necessary conditions for these results to hold and suggest that they are likely to be common in the seasonally dry tropics, offering potential for widespread tree establishment and increased benefits for hundreds of millions of people.

The effect of trees on preferential flow and soil infiltrability in an agroforestry parkland in semiarid Burkina Faso.

Water scarcity constrains the livelihoods of millions of people in tropical drylands. Tree planting in these environments is generally discouraged due to the large water consumption by trees, but this view may neglect their potential positive impacts on water availability. The effect of trees on soil hydraulic properties linked to groundwater recharge is poorly understood. In this study, we performed 18 rainfall simulations and tracer experiments in an agroforestry parkland in Burkina Faso to investigate the effect of trees and associated termite mounds on soil infiltrability and preferential flow. The sampling points were distributed in transects each consisting of three positions: (i) under a single tree, (ii) in the middle of an open area, and (iii) under a tree associated with a termite mound. The degree of preferential flow was quantified through parameters based on the dye infiltration patterns, which were analyzed using image analysis of photographs. Our results show that the degree of preferential flow was highest under trees associated with termite mounds, intermediate under single trees, and minimal in the open areas. Tree density also had an influence on the degree of preferential flow, with small open areas having more preferential flow than large ones. Soil infiltrability was higher under single trees than in the open areas or under trees associated with a termite mound. The findings from this study demonstrate that trees have a positive impact on soil hydraulic properties influencing groundwater recharge, and thus such effects must be considered when evaluating the impact of trees on water resources in drylands. KEY POINTS: Trees in dryland landscapes increase soil infiltrability and preferential flow Termite mounds in association with trees further enhance preferential flow.