Contamination des Laits Importés au Mali par l’Aflatoxine M1

Au Mali l’insuffisance de données scientifiques sur la contamination du lait par les aflatoxines a motivé la conduite de la présente étude. Les aflatoxines sont des métabolites secondaires synthétisés par des souches d'As. flavus, Asp. Parasiticus et Asp. Nomius. Aspergillus flavus produit principalement l’Aflatoxine B1 et B2.  AFM1 est retrouvée dans le lait des mammifères lorsque ceux-ci ont ingéré des aliments contaminés par l’Aflatoxine B1. L’hépatotoxité est la caractéristique majeure de l’aflatoxine B1.  AFM1 est reclassée par l'Agence Internationale pour la Recherche sur le Cancer de l'Organisation Mondiale de la Santé pour être dans le groupe 1 au lieu du groupe 2 considéré moins toxique. Contribuer à la connaissance de la qualité sanitaire du lait importé au Mali et conduire une évaluation des risques liés à l’Aflatoxine M1. Etude transversale et descriptive par sondage aléatoire simple. Un total de 150 échantillons de laits a été récolté dans le District de Bamako en 2015.La détermination des teneurs du lait en Aflatoxine M1 a été effectuée par Immunoafinité /HPLC INF selon la norme ISO 14501au CARSO-Laboratoire Santé Environnement Hygiène de Lyon en 2016.Les résultats ont montré que tous les 150 échantillons analysés sont contaminés par l’Aflatoxine M1 avec des taux allant de 30 à100 ng/Kg.Cepandant les taux de contamination étaient inférieures à la norme requise par le Codex Alimentarius qui est de l’ordre de 500ng/Kg. Les acteurs impliqués dans la sécurité sanitaire des aliments aux Mali sont interpellés pour prise de disposition

Assessment and enhancement of MERRA land surface hydrology estimates

The Modern-Era Retrospective Analysis for Research and Applications (MERRA) is a state-of-the-art reanalysis that provides, in addition to atmospheric fields, global estimates of soil moisture, latent heat flux, snow, and runoff for 1979 present. This study introduces a supplemental and improved set of land surface hydrological fields ("MERRA-Land") generated by rerunning a revised version of the land component of the MERRA system. Specifically, the MERRA-Land estimates benefit from corrections to the precipitation forcing with the Global Precipitation Climatology Project pentad product (version 2.1) and from revised parameter values in the rainfall interception model, changes that effectively correct for known limitations in the MERRA surface meteorological forcings. The skill (defined as the correlation coefficient of the anomaly time series) in land surface hydrological fields from MERRA and MERRA-Land is assessed here against observations and compared to the skill of the state-of-the-art ECMWF Re-Analysis-Interim (ERA-I). MERRA-Land and ERA-I root zone soil moisture skills (against in situ observations at 85 U.S. stations) are comparable and significantly greater than that of MERRA. Throughout the Northern Hemisphere, MERRA and MERRA-Land agree reasonably well with in situ snow depth measurements (from 583 stations) and with snow water equivalent from an independent analysis. Runoff skill (against naturalized stream flow observations from 18 U.S. basins) of MERRA and MERRA-Land is typically higher than that of ERA-I. With a few exceptions, the MERRA-Land data appear more accurate than the original MERRA estimates and are thus recommended for those interested in using MERRA output for land surface hydrological studies

Heliconiini butterflies can learn time-dependent reward associations.

For many pollinators, flowers provide predictable temporal schedules of resource availability, meaning an ability to learn time-dependent information could be widely beneficial. However, this ability has only been demonstrated in a handful of species. Observations of Heliconius butterflies suggest that they may have an ability to form time-dependent foraging preferences. Heliconius are unique among butterflies in actively collecting pollen, a dietary behaviour linked to spatio-temporally faithful 'trap-line' foraging. Time dependency of foraging preferences is hypothesized to allow Heliconius to exploit temporal predictability in alternative pollen resources. Here, we provide the first experimental evidence in support of this hypothesis, demonstrating that Heliconius hecale can learn opposing colour preferences in two time periods. This shift in preference is robust to the order of presentation, suggesting that preference is tied to the time of day and not due to ordinal or interval learning. However, this ability is not limited to Heliconius, as previously hypothesized, but also present in a related genus of non-pollen feeding butterflies. This demonstrates time learning likely pre-dates the origin of pollen feeding and may be prevalent across butterflies with less specialized foraging behaviours

Estimation du nombre de greffons produits par l’anacardier (Anacardium occidentale L.) : influence du genotype du porte-greffe et des parametres architecturaux

La demande en plants greffés des clones hauts producteurs d’anacardier (Anacardium occidentale L.), s’accroît au fil des années. Afin de mieux planifier la fourniture de plants greffés et satisfaire la demande, il s’avère nécessaire de mettre au point une méthode simple de détermination de la quantité maximale de greffons et de plants susceptibles d’être produits au cours d’une année. A cet effet, l’architecture des anacardiers issus du greffage du clone haut producteur LAX3264 sur trois porte-greffes a été étudiée. Les résultats ont révélé deux types d’architecture, semi-érigée ou érigéeouverte selon le génotype du porte-greffe. Ces deux types d’architecture n’influencent pas significativement la majorité des paramètres évalués. En revanche, le diamètre à 10 cm du sol et l’envergure moyenne de la plante greffée ont varié significativement selon le génotype du porte-greffe. Quel que soit le génotype du porte-greffe et le type d’architecture, l’envergure moyenne de la plante est un estimateur efficace du nombre de greffons produits par l’anacardier greffé. L’équation d’allométrie est de type : Y= 162,4755X-376,9773. Ainsi, cette étude a permis de mettre au point une méthode simple et fiable d’estimation du nombre de greffons par plante. Mots clés: Anacardier ; architecture ; envergure ; greffons, équation d’allométrie English Title: Estimate of the number of grafts produced by the cashew tree (Anacardium occidentale L.): influence of the genotype of the rootstock and architectural parameters English Abstract The demand for grafted seedlings of the high-producing clones of cashew tree (Anacardium occidentale L.), has increased over t he years. In order to better plan the supply of seedlings and meet the producer’s request, it proves to be necessary to develop a simple method for estimating the maximum quantity of scions and seedlings likely to be produced during one year. For this purpose the architecture of the cashew trees resulting from the grafting of the high-producing clone LA X3264 on three rootstocks was studied.The results showed two types of architecture, semi-erected or openerected, depending on the rootstock genotype.These two types of architecture did not influence significantly the parameters assessed. By contrast, the diameter at 10 cm from the ground and the average span of the grafted plant varied significantly according to the genotype of the rootstock. Whatever the genotype of the rootstock and the type of archi-tecture, the average plant span was an effective estimator of the scions produced by the grafted cashew tree. The allometric equation found was : Y=162.4755X-376.9773. Thus, this study provided a simple and reliable method for estimating the number of scions of grafted cashew tree. Keywords : Cashew tree ; architecture ; span ; scions, Allometric equatio

A randomised trial in Mali of the effectiveness of weekly iron supplements given by teachers on the haemoglobin concentrations of schoolchildren

Objective: To assess the effect on the haemoglobin concentrations of schoolchildren of weekly iron tablets administered by teachers. Design: Sixty schools were randomly assigned to two groups: in 30 schools children were given weekly for 10 weeks a tablet providing 65 mg of iron and 0.25 mg of folic acid; in the other 30 schools no iron tablets were given. All children were dewormed and given vitamin A before the study began. The haemoglobin concentration of up to 20 randomly selected children in each school was estimated before and 2 weeks after the end of treatment. Setting: Rural community schools in Kolondieba district of Mali. Subjects: Some 1113 schoolchildren aged 6-19 years with a mean of 11.4 years. Results: The haemoglobin concentration of treated children rose on average by 1.8 g l -1 (P < 0.001) and the prevalence of anaemia fell by 8.2% (P < 0.001); in untreated children the haemoglobin concentration fell by an average of 22.7 g l -1 (P < 0.001) and the prevalence of anaemia rose by 9.4% (P < 0:001). The fall in haemoglobin concentration among untreated girls of 24.0 g l21 was greater than in untreated boys (20.3 g l -1 (P < 0.001). Conclusions: Weekly iron tablets given by teachers prevented a general fall in the haemoglobin concentrations of untreated children, and led to a small but statistically significant rise among treated children (P < 0.001). Young children benefited more than children aged </=12 years, and girls benefited more than boys

Assimilation of MODIS Snow Cover Fraction Observations into the NASA Catchment Land Surface Model

The NASA Catchment land surface model (CLSM) is the land model component used for the Modern-Era Retrospective Analysis for Research and Applications (MERRA). Here, the CLSM versions of MERRA and MERRA-Land are evaluated using snow cover fraction (SCF) observations from the Moderate Resolution Imaging Spectroradiometer (MODIS). Moreover, a computationally-efficient empirical scheme is designed to improve CLSM estimates of SCF, snow depth, and snow water equivalent (SWE) through the assimilation of MODIS SCF observations. Results show that data assimilation (DA) improved SCF estimates compared to the open-loop model without assimilation (OL), especially in areas with ephemeral snow cover and mountainous regions. A comparison of the SCF estimates from DA against snow cover estimates from the NOAA Interactive Multisensor Snow and Ice Mapping System showed an improvement in the probability of detection of up to 28% and a reduction in false alarms by up to 6% (relative to OL). A comparison of the model snow depth estimates against Canadian Meteorological Centre analyses showed that DA successfully improved the model seasonal bias from 0.017 m for OL to 0.007 m for DA, although there was no significant change in root-mean-square differences (RMSD) (0.095 m for OL, 0.093 m for DA). The time-average of the spatial correlation coefficient also improved from 0.61 for OL to 0.63 for DA. A comparison against in situ SWE measurements also showed improvements from assimilation. The correlation increased from 0.44 for OL to 0.49 for DA, the bias improved from 0.111 m for OL to 0.100 m for DA, and the RMSD decreased from 0.186 m for OL to 0.180 m for DA

Rapid Molecular Assays for Specific Detection and Quantitation of Loa loa Microfilaremia

Loa loa is a filarial nematode that infects over 10 million people in Africa. Most infections cause no symptoms, but individuals with large numbers of blood-stage microfilariae are at risk for fatal reactions to ivermectin, an antiparasitic agent used to treat and prevent infections with Onchocerca volvulus, a related filarial parasite that may occur alongside L. loa. To address the urgent need for a point-of-care L. loa diagnostic assay, we screened a Loa microfilaria gene expression library and identified 18 Loa-specific DNA targets. From two targets, we developed a novel, rapid quantitative PCR assay for estimating L. loa microfilaria burden. The assay is highly sensitive (detects a single microfilaria in 20 µL of blood) and correlates well with microfilaria counts obtained with conventional microscopic techniques. The assay is species-specific for L. loa compared with related filarial parasites (including O. volvulus) and can be used in its current form in resource-rich areas as a diagnostic tool for L. loa infection. Although modifications will be required to make point-of-care use feasible, our assay provides a proof of concept for a potentially valuable tool to identify individuals at risk for adverse reactions to ivermectin and to facilitate the implementation of filarial control programs

Differential infectivity of gametocytes after artemisinin-based combination therapy of uncomplicated falciparum malaria

Background: Most malaria-endemic countries use artemisinin-based combination therapy (ACT) as their first-line treatment. ACTs are known to be highly effective on asexual stages of the malaria parasite. Malaria transmission and the spread of resistant parasites depend on the infectivity of gametocytes. The effect of the current ACT regimens on gametocyte infectivity is unclear. Objectives: This study aimed to determine the infectivity of gametocytes to Anopheles gambiae following ACT treatment in the field. Methods: During a randomised controlled trial in Bougoula-Hameau, Mali, conducted from July 2005 to July 2007, volunteers with uncomplicated malaria were randomised to receive artemether-lumefantrine, artesunate-amodiaquine, or artesunate-sulfadoxine/pyrimethamine. Volunteers were followed for 28 days, and gametocyte carriage was assessed. Direct skin feeding assays were performed on gametocyte carriers before and after ACT administration. Results: Following artemether-lumefantrine treatment, gametocyte carriage decreased steadily from Day 0 to Day 21 post-treatment initiation. In contrast, for the artesunate-amodiaquine and artesunate-sulfadoxine/pyrimethamine arms, gametocyte carriage increased on Day 3 and remained constant until Day 7 before decreasing afterward. Mosquito feeding assays showed that artemether-lumefantrine and artesunate-amodiaquine significantly increased gametocyte infectivity to Anopheles gambiae sensu lato (s.l.) (p < 10−4), whereas artesunate-sulfadoxine/pyrimethamine decreased gametocyte infectivity in this setting (p = 0.03). Conclusion: Different ACT regimens could lead to gametocyte populations with different capacity to infect the Anopheles vector. Frequent assessment of the effect of antimalarials on gametocytogenesis and gametocyte infectivity may be required for the full assessment of treatment efficacy, the potential for spread of drug resistance and malaria transmission in the field