Caractérisation agromorphologique des accessions de riz adventices (Oryza sp) collectés dans les rizières de la zone interfluve du Tchad

Le riz est la céréale de base des populations des Régions administratives de la Tandjilé et du Mayo- Kebbi Est, dans le sud du Tchad. Le rendement du riz est cependant relativement très bas (moins de 1 t/ha). Ceci est lié à plusieurs facteurs parmi lesquels la forte infestation des rizières par les riz adventices et la faible utilisation des semences des variétés améliorées haut rendement. Parmi les mauvaises herbes, les plus fréquentes et nocives pour le riz cultivé, sont les espèces comme Oryza sativa L., Oryza barthii (A Chev) et Oryza longistaminata (A. Chev et Roehr). Celles-ci montrent une forte dynamique de l'infestation dans les rizières des plaines inondées des Régions administratives de la Tandjilé et du Mayo-Kebbi Est. La caractérisation agromorphologique de 24 échantillons riz adventices issus des opérations de prospectioncollecte d'octobre 2005 à Mars 2006 a été réalisée. A partir d’un dispositif de Ficher à trois répétitions, une expérimentation a permis de mettre en évidence, par une analyse de variance , une classification ascendante hiérarchique et l'analyse factorielle discriminante, l'existence de cinq groupes de riz adventices

Effect of chemical fertilizers on production of yams (nyù) of passore in farmers’ environment

Nyù is the main morphotype of yams of Passoré. It is generally cultivated without chemical fertilizer. The study aims to determine the effect of one rate of chemical fertilizers on the yield of yams « nyù » of Passoré in farmers’ environment of Burkina Faso and to collect the appreciations of the various actors about tubers in the production chain. The results reveal that chemical fertilizer involved a better expression of the agro-morphological parameters and an increase of the tubers yield which reaches 42.5 t / ha compared to the field not fertilized where tuber yield is slow (9 t / ha). However, tubers obtained of treated field have not a good organoleptic quality whereas the tubers of untreated fields have good taste. Moreover, the chemical fertilizer changed also the morphology, taste and consistency of the tubers. These results could help all actors to choose the best method of nyù production according to their objectives.Keywords: nyù, yam, mineral fertlizer, Passoré, Burkina Fas

Prevalence of Escherichia coli virulence genes in patients with diarrhoea in Ouagadougou, Burkina Faso

Objective: Diarrhoeagenic E. coli (DEC) strains are important causes of diarrhoea in the developing world and, to a lesser extent, inthe developed world. In this study, we investigated the prevalence of the virulence genes specific for five major pathogroups of diarrheagenic Escherichia coli (DEC) in primary cultures from diarrhoeagenic patients in Burkina Faso.Methodology: From September 2016 to Mars 2017, a total of 211 faecal samples from diarrhoeagenic patients from urban hospitals of Ouagadou, Burkina Faso have been analysed. A 16-plex PCR was used to detect simultaneously, the five major DEC pathotypes (enteropathogenic E. coli (EPEC), enterotoxigenic E. coli (ETEC), Shiga toxin-producing E. coli (STEC), enteroaggregative E. coli (EAEC) and enteroinvasive E. coli (EIEC)).Results: At least one diarrhoeagenic E. Coli pathotype was detected in 31 samples (14.7%) in children and adults with diarrhoea. EAEC was the most common pathotype detected 9.5% (20/211), followed by EIEC2.4% (05/211) and STEC 0.5% (01/211). More than one DEC pathotype were detected in 2.4% (05/211) patients. EPEC and ETEC were not detected in single infection but in co-infection with others pathotypes.Conclusion: DEC, especially enteroaggregative, may be important responsible of diarrhoeas in Burkina Faso from all ages patient.Key Words: Diarrhoeagenic Escherichia coli, 16-plex PCR, Burkina Faso, human diarrhoeas stool

Seasonal use case for the RTS,S/AS01 malaria vaccine: a mathematical modelling study

BACKGROUND: A 2021 clinical trial of seasonal RTS,S/AS01E (RTS,S) vaccination showed that vaccination was non-inferior to seasonal malaria chemoprevention (SMC) in preventing clinical malaria. The combination of these two interventions provided significant additional protection against clinical and severe malaria outcomes. Projections of the effect of this novel approach to RTS,S vaccination in seasonal transmission settings for extended timeframes and across a range of epidemiological settings are needed to inform policy recommendations. METHODS: We used a mathematical, individual-based model of malaria transmission that was fitted to data on the relationship between entomological inoculation rate and parasite prevalence, clinical disease, severe disease, and deaths from multiple sites across Africa. The model was validated with results from a phase 3b trial assessing the effect of SV-RTS,S in Mali and Burkina Faso. We developed three intervention efficacy models with varying degrees and durations of protection for our population-level modelling analysis to assess the potential effect of an RTS,S vaccination schedule based on age (doses were delivered to children aged 6 months, 7·5 months, and 9 months for the first three doses, and at 27 months of age for the fourth dose) or season (children aged 5-17 months at the time of first vaccination received the first three doses in the 3 months preceding the transmission season, with any subsequent doses up to five doses delivered annually) in seasonal transmission settings both in the absence and presence of SMC with sulfadoxine-pyrimethamine plus amodiaquine. This is modelled as a full therapeutic course delivered every month for four or five months of the peak in transmission season. Estimates of cases and deaths averted in a population of 100 000 children aged 0-5 years were calculated over a 15-year time period for a range of levels of malaria transmission intensity (Plasmodium falciparum parasite prevalence in children aged 2-10 years between 10% and 65%) and over two west Africa seasonality archetypes. FINDINGS: Seasonally targeting RTS,S resulted in greater absolute reductions in malaria cases and deaths compared with an age-based strategy, averting an additional 14 000-47 000 cases per 100 000 children aged 5 years and younger over 15 years, dependent on seasonality and transmission intensity. We predicted that adding seasonally targeted RTS,S to SMC would reduce clinical incidence by up to an additional 42 000-67 000 cases per 100 000 children aged 5 years and younger over 15 years compared with SMC alone. Transmission season duration was a key determinant of intervention effect, with the advantage of adding RTS,S to SMC predicted to be smaller with shorter transmission seasons. INTERPRETATION: RTS,S vaccination in seasonal settings could be a valuable additional tool to existing interventions, with seasonal delivery maximising the effect relative to an age-based approach. Decisions surrounding deployment strategies of RTS,S in such settings will need to consider the local and regional variations in seasonality, current rates of other interventions, and potential achievable RTS,S coverage. FUNDING: UK Medical Research Council, UK Foreign Commonwealth & Development Office, The Wellcome Trust, and The Royal society

PlasmoView: A Web-based Resource to Visualise Global Plasmodium falciparum Genomic Variation

Malaria is a global public health challenge, with drug resistance a major barrier to disease control and elimination. To meet the urgent need for better treatments and vaccines, a deeper knowledge of Plasmodium biology and malaria epidemiology is required. An improved understanding of the genomic variation of malaria parasites, especially the most virulent Plasmodium falciparum (Pf) species, has the potential to yield new insights in these areas. High-throughput sequencing and genotyping is generating large amounts of genomic data across multiple parasite populations. The resulting ability to identify informative variants, particularly single-nucleotide polymorphisms (SNPs), will lead to the discovery of intra- and inter-population differences and thus enable the development of genetic barcodes for diagnostic assays and clinical studies. Knowledge of genetic variability underlying drug resistance and other differential phenotypes will also facilitate the identification of novel mutations and contribute to surveillance and stratified medicine applications. The PlasmoView interactive web-browsing tool enables the research community to visualise genomic variation and annotation (eg, biological function) in a geographic setting. The first release contains over 600 000 high-quality SNPs in 631 Pf isolates from laboratory strains and four malaria-endemic regions (West Africa, East Africa, Southeast Asia and Oceania)

PlasmoView: a web-based resource to visualise global Plasmodium falciparum genomic variation.

Malaria is a global public health challenge, with drug resistance a major barrier to disease control and elimination. To meet the urgent need for better treatments and vaccines, a deeper knowledge of Plasmodium biology and malaria epidemiology is required. An improved understanding of the genomic variation of malaria parasites, especially the most virulent Plasmodium falciparum (Pf) species, has the potential to yield new insights in these areas. High-throughput sequencing and genotyping is generating large amounts of genomic data across multiple parasite populations. The resulting ability to identify informative variants, particularly single-nucleotide polymorphisms (SNPs), will lead to the discovery of intra- and inter-population differences and thus enable the development of genetic barcodes for diagnostic assays and clinical studies. Knowledge of genetic variability underlying drug resistance and other differential phenotypes will also facilitate the identification of novel mutations and contribute to surveillance and stratified medicine applications. The PlasmoView interactive web-browsing tool enables the research community to visualise genomic variation and annotation (eg, biological function) in a geographic setting. The first release contains over 600,000 high-quality SNPs in 631 Pf isolates from laboratory strains and four malaria-endemic regions (West Africa, East Africa, Southeast Asia and Oceania)

VARIATION, CORRELATION AND HERITABILITY OF INTEREST CHARACTERS FOR SELECTION OF AFRICAN EGGPLANT

The eggplant ( Solanum aethiopicum ) is the species of the Solanum genus, whose geographical distribution is broadest. It is grown throughout tropical Africa, and includes three groups of cultivars commonly called African or indigenous eggplant. Kumba group or \u201cbitter eggplant\u201d is an important Solanaceous vegetable crop in Burkina Faso. The objective of this study was to determine genetic variability, strength of association and level of heritability among agronomic interest traits. Phenotypic and genotypic variations and heritability of 14 traits were estimated in 61 accessions at Institut de D\ue9veloppement Rural (IDR), Gampela in Burkina Faso. High phenotypic and genotypic coefficients of variation were observed for fruit diameter, number of seeds per fruit, fruit weight, leaf blade length and width, and height at flowering. In addition, genetic and phenotypic variances were high for the number of seed, fruit weight, plant height at flowering and days to 50% flowering. High heritability estimates were recorded for all traits. Fruit weight showed a positive association with fruit diameter and thickness. The fifty percent flowering cycle registered positive correlations with plant height and fruit diameter. Fruit number showed a negative association with fruit weight and diameter, and 50% flowering cyle.Solanum aethiopicum est une esp\ue8ce largement r\ue9pandue en Afrique tropicale. Au Burkina Faso, parmi les Solanac\ue9es, l\u2019aubergine africaine du cultivar Kumba est l\u2019une des plus importants l\ue9gumes. L\u2019objectif g\ue9n\ue9ral de cette \ue9tude est de contribuer \ue0 une meilleure connaissance de la plante \ue0 travers un certain nombre de caract\ue8res d\u2019int\ue9r\ueats. Ainsi, soixante-un accessions ont \ue9t\ue9 \ue9valu\ue9es selon un dispositif compl\ue8tement randomis\ue9 afin de d\ue9terminer la variabilit\ue9 g\ue9n\ue9tique, les corr\ue9lations et le niveau d\u2019h\ue9ritabilit\ue9 de 14 caract\ue8res d\u2019int\ue9r\ueats agromorphologiques. Pour se faire, les variances ph\ue9notypiques et g\ue9notypiques ainsi que l\u2019h\ue9ritabilit\ue9 de ces caract\ue8res ont \ue9t\ue9 estim\ue9es. De forts coefficients de variations ph\ue9notypique et g\ue9notypique ont \ue9t\ue9 observ\ue9s pour les caract\ue8res, diam\ue8tre du fruit, le nombre de graines par fruit, le poids du fruit, la longueur et la largeur de la feuilles, la longueur du p\ue9tiole et la hauteur de la plante \ue0 la floraison. En plus, les variances g\ue9notypiques et ph\ue9notypiques sont \ue9lev\ue9es pour le nombre de graines par fruit, le poids du fruit, la hauteur de la plante \ue0 la floraison et le cycle 50% floraison. L\u2019h\ue9ritabilit\ue9 estim\ue9e s\u2019est r\ue9v\ue9l\ue9e forte pour tous les caract\ue8res. Le poids du fruit est positivement corr\ue9l\ue9 aux dimensions du fruit. Quant au cycle 50% floraison, il est positivement corr\ue9lation \ue0 la hauteur de la plante \ue0 la floraison et le diam\ue8tre du fruit. Le nombre de fruit par plant indique une corr\ue9lation n\ue9gative avec les dimensions du fruit et le cycle 50% floraison. Le r\ue9sultat le plus remarquable est l\u2019absence de corr\ue9lation entre le nombre de graines par fruit et le diam\ue8tre du fruit. Cela sugg\ue8re la possibilit\ue9 d\u2019une s\ue9lection syst\ue9matique d\u2019accessions \ue0 gros fruits contenant moins de graines

A barcode of organellar genome polymorphisms identifies the geographic origin of Plasmodium falciparum strains

Malaria is a major public health problem that is actively being addressed in a global eradication campaign. Increased population mobility through international air travel has elevated the risk of re-introducing parasites to elimination areas and dispersing drug-resistant parasites to new regions. A simple genetic marker that quickly and accurately identifies the geographic origin of infections would be a valuable public health tool for locating the source of imported outbreaks. Here we analyse the mitochondrion and apicoplast genomes of 711 Plasmodium falciparum isolates from 14 countries, and find evidence that they are non-recombining and co-inherited. The high degree of linkage produces a panel of relatively few single-nucleotide polymorphisms (SNPs) that is geographically informative. We design a 23-SNP barcode that is highly predictive (~92%) and easily adapted to aid case management in the field and survey parasite migration worldwide

A barcode of organellar genome polymorphisms identifies the geographic origin of Plasmodium falciparum strains.

Malaria is a major public health problem that is actively being addressed in a global eradication campaign. Increased population mobility through international air travel has elevated the risk of re-introducing parasites to elimination areas and dispersing drug-resistant parasites to new regions. A simple genetic marker that quickly and accurately identifies the geographic origin of infections would be a valuable public health tool for locating the source of imported outbreaks. Here we analyse the mitochondrion and apicoplast genomes of 711 Plasmodium falciparum isolates from 14 countries, and find evidence that they are non-recombining and co-inherited. The high degree of linkage produces a panel of relatively few single-nucleotide polymorphisms (SNPs) that is geographically informative. We design a 23-SNP barcode that is highly predictive (~92%) and easily adapted to aid case management in the field and survey parasite migration worldwide