Biological activities of four essential oils against Anopheles gambiae in Burkina Faso and their in vitro inhibition of acetylcholinesterase

The control of malaria is still a challenge partly due to mosquito’s resistance to current available insecticides. The aim of this work was to evaluate the ovicidal, larvicidal and repellent activities of Lantana camara, Hyptis suaveolens, Hyptis spicigera and Ocimum canum essential oils against  Anopheles gambiae s.l.  according to the World Health Organization standard method. The in vitro acetylcholinesterase inhibition activity of these oils was also evaluated. The repellent effect using the method of “separated arms” was evaluated. Lantana camara oil was more effective on both eggs and larvae. The LD50 and LD90 values observed in this oil solution were respectively 53.59 and 170.89 ppm on eggs whereas LD50 and LD90 were 61 and 125 ppm respectively on larvae. All oils exhibited repellent activities against adult mosquitoes. The most effective repellent was the oil of Hyptis suaveolens with a 50% efficacy dose value of 67 ppm. The highest  cetylcholinesterase inhibitory activity was observed with O. canum and H. suaveolens essential oils which IC50 was 0.21 and 0.55 μg/ml respectively. Results suggest that these essential oils have a potential for vector control and can be considered as a source of natural and ecofriendly substances for malaria vector control.Keywords: Anopheles gambiae s.l., malaria, essential oil, acetylcholinesterase, insecticidal activity

Research and development partnerships for a large-scale diffusion of technologies for sorghum and millet systems in Mali

The objective of this work is to improve production systems based on sorghum and pearl millet in the Mopti and Sikasso regions of Mali, by strengthening research and development partnerships for large-scale utilization of proven technologies with potential for improving nutrition, benefiting women and children, and enhancing the sustainability of smallholder agriculture. At the farm level, the focus has been to improve production by increasing access to selected new technologies, and enhancing awareness and ‘knowhow’ for the use of existing technologies to enhance sorghum and millet production. In the Mopti and Sikasso regions of Mali, the major technologies targeted for dissemination include: i) the use of seed treatment such as Apron Star 42WS, ii) seed of improved varieties of pearl millet, sorghum (both hybrid and open pollinated varieties), groundnut and cowpea adapted to the Sahelian environmental conditions, iii) integrated Striga and soil-fertility management practices; and iv) biological control of the millet head-miner. Seed treatment of pearl millet with Apron Star significantly reduced the incidence and severity of diseases. Grain yield was 20% higher when seed was treated. Further, the practice increases yield by 39% relative to farmers’ current practice

Analysis of stakeholder perceptions and practices related to climate change adaptation in Burkina Faso

Burkina Faso, like other Sahelian countries, has experienced a profound change in its climatic regime, with the new context characterised by high rainfall variability with an overall downward trend and a shortening of the seasons. The future rainfall pattern anticipates a decrease in the frequency of low rainfall (0.1 to 5 mm per day), a lengthening of the average duration of dry sequences, and an early end and late start of rainy seasons. The objective of this study was to perform an in-depth analysis of stakeholder perceptions about agricultural water (AgWater) resources sustainability, practices in the context of climate variability and change in Burkina Faso. Interviews were held with institutional actors involved in water resources decision making and initiatives (Government, Research, Non-Governmental Organisations) in the country. In addition, based on four main criteria (climate condition, type of farm and crop, type of AgWater sources, reliability of AgWater), three agricultural sites were investigated using household surveys. The results showed that organisations and farmers in Burkina Faso were aware of climate impacts and had initiated and implemented for many years, diverse options and water control mechanisms for AgWater adaptation. However, there were still gaps in strategies for adapting the water sector to climate threats. Institutional bodies had not got yet attained capacity to sustainably anticipate the effects of climate change on AgWater. There was a lack of mainstreaming hydroclimate services at farm levels, especially for the dry season crops; lack of on-farm flood control mechanisms, absence of a clear gender approach and no standardised monitoring system, Farmers also lacked anticipatory resilience strategies, particularly those who used water sources that were considered as \u201creliable\u201d then. In general, most of the climate adaptation initiatives implemented lacked synergies, sustainability, and were uncertain about sound water resource management such as moving towards \u201cno regret\u201d and \u201cwin-win\u201d options.Le Burkina Faso, \ue0 l\u2019instar des pays du Sahel, a connu un changement consid\ue9rable de son r\ue9gime climatique. Le nouveau contexte climatique est caract\ue9ris\ue9 par une forte variabilit\ue9 et une baisse de la fr\ue9quence des pr\ue9cipitations (0,1 \ue0 5 mm par jour), un allongement de la dur\ue9e moyenne des s\ue9quences s\ue8ches, une fin pr\ue9coce et un d\ue9but tardif des saisons des pluies. L\u2019objectif de cette \ue9tude \ue9tait donc d\u2019effectuer une analyse approfondie des perceptions et pratiques des acteurs au regard de la s\ue9curit\ue9 en eau agricole dans un contexte de changement climatique au Burkina Faso. Des entretiens semi-structur\ue9s ont \ue9t\ue9 conduits avec les acteurs institutionnels impliqu\ue9s dans la gestion de l\u2019eau agricole (d\ue9cideurs, chercheurs, praticiens). Aussi, sur la base de quatre crit\ue8res principaux (conditions climatiques, type d\u2019exploitation et de cultures, type de sources d\u2019eau agricole, fiabilit\ue9 de la source d\u2019eau), trois sites agricoles ont \ue9t\ue9 s\ue9lectionn\ue9s et des enqu\ueates conduites aupr\ue8s des agriculteurs. Les r\ue9sultats ont montr\ue9 que l\u2019ensemble des acteurs institutionnels ou usagers exp\ue9rimentent les effets du climat sur l\u2019eau agricole. En outre, de nombreuses initiatives et m\ue9canismes, qui contribuent \ue0 l\u2019adaptation de cette ressource, ont \ue9t\ue9 mis en \u153uvre depuis de nombreuses ann\ue9es. Toutefois, il existe encore de nombreuses lacunes dans les strat\ue9gies pour une adaptation durable de l\u2019eau agricole aux menaces climatiques. Les acteurs institutionnels n\u2019ont pas encore la capacit\ue9 d\u2019anticiper efficacement les effets des changements climatiques. Il n\u2019existe pas encore de services hydroclimatiques au niveau des exploitations agricoles, notamment pour les cultures de saison s\ue8che ; de m\ueame que l\u2019absence de m\ue9canismes de maitrise des inondations sur ces exploitations agricoles, la promotion d\u2019une approche genre sp\ue9cifique et le manque d\u2019un syst\ue8me standard de suivi de la r\ue9silience. Les agriculteurs manquent de strat\ue9gies anticipatives d\u2019adaptation, en particulier autour des sources d\u2019eau consid\ue9r\ue9es comme \u201cfiables\u201d. En g\ue9n\ue9ral, la plupart des initiatives actuelles d\u2019adaptation au climat manquent de synergies, et la prise en compte de l\u2019incertitude climatique comme l\u2019orientation vers les \u201c options sans \u201cregret\u201d ou \u201cgagnant-gagnant\u201d

Distance to care, care seeking and child mortality in rural Burkina Faso: findings from a population-based cross-sectional survey.

OBJECTIVE: Although distance has been identified as an important barrier to care, evidence for an effect of distance to care on child mortality is inconsistent. We investigated the association of distance to care with self-reported care seeking behaviours, neonatal and post-neonatal under-five child mortality in rural areas of Burkina Faso. METHODS: We performed a cross-sectional survey in 14 rural areas from November 2014 to March 2015. About 100 000 women were interviewed on their pregnancy history and about 5000 mothers were interviewed on their care seeking behaviours. Euclidean distances to the closest facility were calculated. Mixed-effects logistic and Poisson regressions were used respectively to compute odds ratios for care seeking behaviours and rate ratios for child mortality during the 5 years prior to the survey. RESULTS: Thirty per cent of the children lived more than 7 km from a facility. After controlling for confounding factors, there was a strong evidence of a decreasing trend in care seeking with increasing distance to care (P ≤ 0.005). There was evidence for an increasing trend in early neonatal mortality with increasing distance to care (P = 0.028), but not for late neonatal mortality (P = 0.479) and post-neonatal under-five child mortality (P = 0.488). In their first week of life, neonates living 7 km or more from a facility had an 18% higher mortality rate than neonates living within 2 km of a facility (RR = 1.18; 95%CI 1.00, 1.39; P = 0.056). In the late neonatal period, despite the lack of evidence for an association of mortality with distance, it is noteworthy that rate ratios were consistent with a trend and similar to or larger than estimates in early neonatal mortality. In this period, neonates living 7 km or more from a facility had an 18% higher mortality rate than neonates living within 2 km of a facility (RR = 1.18; 95%CI 0.92, 1.52; P = 0.202). Thus, the lack of evidence may reflect lower power due to fewer deaths rather than a weaker association. CONCLUSION: While better geographic access to care is strongly associated with increased care seeking in rural Burkina Faso, the impact on child mortality appears to be marginal. This suggests that, in addition to improving access to services, attention needs to be paid to quality of those services

A watershed approach to managing rainfed agriculture in the semiarid region of southern Mali: integrated research on water and land use

Soil and water conservation (SWC) practices like that of erosion control and soil fertility measures were commonly practiced in the semiarid region of southern Mali since the 1980s. The SWC practices were mainly meant to increase water availability in the subsurface, reduce farm water runoff and gully formation and improve nutrient content of the soil, thereby increasing crop yield. Despite such efforts to promote at scale SWC practices, the landscape of southern Mali is still affected by high rates of runoff and soil erosion and low crop yield in farmers’ fields. Data are lacking on previous beneficial SWC practices that could be adapted for wider application. In this paper, a watershed approach to managing rainfed agriculture is presented to show potential benefits of SWC practices at field and watershed scales. The approach included (1) community participation in establishing and monitoring new sets of hydro-meteorological monitoring stations and field experiments; (2) studying the dynamics and consumptive water uses of different land uses over time; and (3) evaluating the biophysical and economic advantages of SWC practices implemented in the watershed. Results showed that over a period of 34 years (1980–2014) cropping area and consumptive water uses of crops (sorghum and cotton) increased at the expenses of natural vegetation. However, the yield of these crops remained low, indicating that soil fertility management and soil moisture were insufficient. In such cases, implementation of more SWC practices can help provide the additional soil moisture required

Translation of liver stage activity of M5717, a Plasmodium elongation factor 2 inhibitor: from bench to bedside

© The Author(s) 2022. Open Access This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. The images or other third party material in this article are included in the article’s Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit http://creativecommons.org/licenses/by/4.0/. The Creative Commons Public Domain Dedication waiver (http://creativeco mmons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated in a credit line to the data.Background: Targeting the asymptomatic liver stage of Plasmodium infection through chemoprevention could become a key intervention to reduce malaria-associated incidence and mortality. Methods: M5717, a Plasmodium elongation factor 2 inhibitor, was assessed in vitro and in vivo with readily accessible Plasmodium berghei parasites. In an animal refinement, reduction, replacement approach, the in vitro IC99 value was used to feed a Population Pharmacokinetics modelling and simulation approach to determine meaningful effective doses for a subsequent Plasmodium sporozoite-induced volunteer infection study. Results: Doses of 100 and 200 mg would provide exposures exceeding IC99 in 96 and 100% of the simulated population, respectively. Conclusions: This approach has the potential to accelerate the search for new anti-malarials, to reduce the number of healthy volunteers needed in a clinical study and decrease and refine the animal use in the preclinical phase.This work was funded by the healthcare business of Merck KGaA, Darmstadt, Germany (CrossRef Funder ID: https://doi.org/10.13039/100009945). F.A. is the recipient of an individual Ph.D. fellowship funded by FCT (PD/BD/128371/2017).info:eu-repo/semantics/publishedVersio

Dengue vector habitats in Ouagadougou, Burkina Faso, 2020: an unintended consequence of the installation of public handwashing stations for COVID-19 prevention

Correspondenc

Putative pleiotropic effects of the knockdown resistance (L1014F) allele on the life-history traits of Anopheles gambiae.

Background Existing mechanisms of insecticide resistance are known to help the survival of mosquitoes following contact with chemical compounds, even though they could negatively affect the life-history traits of resistant malaria vectors. In West Africa, the knockdown resistance mechanism kdrR (L1014F) is the most common. However, little knowledge is available on its effects on mosquito life-history traits. The fitness effects associated with this knockdown resistance allele in Anopheles gambiae sensu stricto (s.s.) were investigated in an insecticide-free laboratory environment. Methods The life-history traits of Kisumu (susceptible) and KisKdr (kdr resistant) strains of An. gambiae s.s. were compared. Larval survivorship and pupation rate were assessed as well as fecundity and fertility of adult females. Female mosquitoes of both strains were directly blood fed through artificial membrane assays and then the blood-feeding success, blood volume and adult survivorship post-blood meal were assessed. Results The An. gambiae mosquitoes carrying the kdrR allele (KisKdr) laid a reduced number of eggs. The mean number of larvae in the susceptible strain Kisumu was three-fold overall higher than that seen in the KisKdr strain with a significant difference in hatching rates (81.89% in Kisumu vs 72.89% in KisKdr). The KisKdr larvae had a significant higher survivorship than that of Kisumu. The blood-feeding success was significantly higher in the resistant mosquitoes (84%) compared to the susceptible ones (34.75%). However, the mean blood volume was 1.36 µL/mg, 1.45 µL/mg and 1.68 µL/mg in Kisumu, homozygote and heterozygote KisKdr mosquitoes, respectively. After blood-feeding, the heterozygote KisKdr mosquitoes displayed highest survivorship when compared to that of Kisumu. Conclusions The presence of the knockdown resistance allele appears to impact the life-history traits, such as fecundity, fertility, larval survivorship, and blood-feeding behaviour in An. gambiae. These data could help to guide the implementation of more reliable strategies for the control of malaria vectors

Classification of Inhibitors of Hepatic Organic Anion Transporting Polypeptides (OATPs): Influence of Protein Expression on Drug–Drug Interactions

ABSTRACT: The hepatic organic anion transporting poly-peptides (OATPs) influence the pharmacokinetics of several drug classes and are involved in many clinical drug−drug interactions. Predicting potential interactions with OATPs is, therefore, of value. Here, we developed in vitro and in silico models for identification and prediction of specific and general inhibitors of OATP1B1, OATP1B3, and OATP2B1. The maximal transport activity (MTA) of each OATP in human liver was predicted from transport kinetics and protein quantification. We then used MTA to predict the effects of a subset of inhibitors on atorvastatin uptake in vivo. Using a data set of 225 drug-like compounds, 91 OATP inhibitors were identified. In silico models indicated that lipophilicity and polar surface area are key molecular features of OATP inhibition. MTA predictions identified OATP1B1 and OATP1B3 as major determinants of atorvastatin uptake in vivo. The relative contributions to overall hepatic uptake varied with isoform specificities of the inhibitors