Diversity and structure of the woody plant communities in the national park of Arly

La présente étude menée sur la végétation ligneuse du parc national d’Arly a pour objectif de caractériser la diversité et la structure des différents groupements végétaux en relation avec les conditions écologiques. 243 relevés phytosociologiques ont été réalisés. Ces relevés font ressortir 109 espèces ligneuses et 10 groupements par la méthode d’analyse DCA. La diversité des groupements végétaux a été caractérisée par le calcul des indices de diversité. Pour chaque groupement ligneux, 10 relevés ont été choisis de manière aléatoire pour des mesures dendrométriques. Les individus dont le diamètre à 1,3 m du sol est supérieur à 5 cm ont été mesurés. La structure des groupements a été décrite à travers la répartition des individus en classe de diamètre, le calcul de la densité et de la surface terrière. La relation entre la diversité et la structure des groupements a été établie sur la base d’analyse de corrélation. Les groupements ligneux distingués sont répartis suivant le gradient topographique. L’analyse de la structure démographique en classe de diamètre montre que les peuplements des différents groupements végétaux sont stables, ce qui traduit leur adaptation aux facteurs écologiques stationnelles telles que le feu et les conditions de sol. Les forêts claires à Tamarindus indica et Combretum paniculatum et les forêts galeries à Vitex chrysocarpa et Garcinia livingstonei sont les formations les plus denses et les groupements ligneux les plus diversifiés. A l’opposé, les savanes arbustives clairsemées à Euphorbia sudanica et Combretum niorense et celles à Acacia sieberiana sont moins denses et constituent les groupements les plus pauvres en espèces. Ainsi, il existe une relation entre la diversité et la structure des groupements des formations ligneuses. Les conditions édaphiques et topographiques occupées par ces groupements expliquent à la fois leur diversité et leur structure. Mots clés: groupements ligneux, relevés, stabilité, solThe diversity and structure of woody vegetation were studied in the national park of Arly in relation to the ecological conditions. After vegetation classification by DCA analysis, diversity parameters, density, basal area and size class distribution of each plant community were determined. We characterised 10 plant communities whose distribution is governed by a topo-edaphic gradient. The patterns of size class distribution show that the stands of all plant communities are in a stable situation. This result shows the adaptation of the vegetation units to the local environmental conditions as fire regime and soil properties. Woodlands of Tamarindus indica and Combretum paniculatum and riparian forests of Vitex chrysocarpa and Garcinia livingstonei possess the high est density and the highest diversity of tree species. In contrary, wooded grasslands of Euphorbia sudanica and Combretum niorense and humid wooded grasslands of Acacia sieberiana are very poor in species and their density is low. These results supported by correlation analysis show a significant relation between diversity and structure. Topo-edaphic conditions are one of the principal environmental factors which drive the diversity and the structure of plant communities. Key words: woody plant community, relevés, stability, soi

Assessing the competitive ability of the invader Senna obtusifolia with coexisting natives species under different water stress regimes

Invasive species tend to pose a threat to ecosystem biodiversity, functioning, and ecosystem service provision. This study was conducted in Burkina Faso to assess the competitiveness of an invasive species Senna obtusifolia that is a less palatable legume plant in West African Sahelian rangelands. To address the research hypothesis that the recurrent drought in the Sahel results in S. obtusifolia being more competitive in the land invasion, we conducted an interspecific competition involving S. obtusifolia and 3 herbaceous species (Andropogon gayanus, Chamaecrista mimosoides, and Pennisetum pedicellatum) in a greenhouse experiment under four water stress regimes using a replacement series design. The height and biomass of each species were measured throughout four months experiment. In the severe water regime, S. obtusifolia was the most sensitive to water deficit while the 3 other species were found to be resistant. In addition, in all water regimes, the aggressivity index revealed that S. obtusifolia was less competitive than the grass species A. gayanus and P. pedicellatum. Further, the study discovered that drought in the Sahel made S. obtusifolia more vulnerable than the other species. Hence the invasion of Sahelian rangelands by S. obtusifolia could be favored by overgrazing that reduces fodder species' dominance and competitiveness. Good management of sahelian rangelands by controlling grazing could help to reduce S. obtusifolia invasion and provide more fodder for livestock

Local Knowledge, Perceptions and Uses Values of Senna obtusifolia (L.) H.S. Irwin & Barneby, an Invasive Native Plant Species in Burkina Faso, West Africa

Invasive species are known to be a threat to agriculture and biodiversity. Thus, many studies have focused on the negative ecological impacts of invasive species, while their importance to livelihoods and human well-being has received little attention. This study aimed to explore people's ethno-ecological knowledge about the invasion of Senna obtusifolia and the importance of this species in some local ethnic groups according to two climate zones in Burkina Faso. Three hundred (300) people from eight (08) ethnic groups from surrounding villages of pastoral zones in two contrast climate zones were interviewed. The survey technique was semi-structured interviews, using a previously tested semi-structured questionnaire. A Generalized Linear Model (GLM) with the Poisson distribution was performed to determine the factors that influence the ethno-ecological knowledge of people. For informants, the most important dissemination drivers are animals in the Sahelian zone and humans in the Sudanian zone. Regarding usefulness, the species is harvested by people for 08 use categories with food (100%) and construction (46%) as the most use categories. In fact, use value of Senna obtusifolia differed significantly among climatic zones, ethnic groups (P < 0.001). Furthermore, a significant difference between the Mossi and Fulani of the Sahelian zone and those of the Sudanian zone was observed. This study revealed the usefulness of Senna obtusifolia for people and findings are essential to promote the species utilization, which could be considered as adaptation strategy to the negative ecological invasion of the species. Moreover, these findings could guide the formulation of management policies and how to valorise more the invasive species

Floristic diversity of classified forest and partial faunal reserve of Comoé-Léraba, southwest Burkina Faso

: The classified forest and partial faunal reserve of Comoé-Léraba belongs to the South Sudanian phytogeographical sector of Burkina Faso and is located in the most humid area of the country. This study aims to present a detailed list of the Comoé-Léraba reserve’s flora for a better knowledge and conservation. Floristic inventories have permitted to record 540 plant species belonging to 342 genera and 91 families, thus representing 26.12% of Burkina Faso’s phytodiversity (2067 species). Fabaceae and Poaceae with 89 and 51 species respectively, were the dominant families. The vegetation is characterized by the dominance of both phanerophytes (45.51%) and therophytes (32.73%). The importance of Guineo–­Con­golian species proves that the Comoé-Léraba flora belongs to the Sudano–Guinean transition sector. Comoé-Léraba also accounts the highest number of exclusive species followed by the reserve of Sahel in the country. Exclusive species bring out its value in flora conservation

Malaria vaccines: Genomic search for profiling naturally acquired immunity

Malaria remains a major public health problem worldwide. Despite many efforts to control or to eliminate the disease many malaria cases and deaths are still reported. The current measures to control malaria include quick diagnosis and treatment of malaria cases, vector control strategies, active research for malaria vaccine discovery and new drugs. Resistance of Plasmodium falciparum to the common and affordable antimalarial drugs as well as the resistance of the malaria vector to usual insecticides has been reported. An effective and affordable malaria vaccine would be the most important tool to control malaria. To date there is no licensed malaria vaccine. Traditional approaches toward malaria vaccine discovery have shown their limitations because of the limited number of proteins that were evaluated. The completion of the genome sequence of Plasmodium falciparum as well as the availability of the high throughput protein microarray immunoassay and other bioinformatic approaches offer the possibility to accelerate and to widen research on malaria vaccine candidates. The harnessing of the well-established model of the naturally acquired immunity (NAI) developed in people living in malaria endemic areas is an important way for the discovery of novel malaria vaccine candidates. Protein microarray is a high throughput technology, which allows the profiling of the humoral immune response to many proteins expressed at different stages of the Plasmodium life cycle in a single experiment. However, despite the hope generated by the sequencing of P. falciparum malaria genome no antigen identified by the protein microarray technology has yet been developed as a potential vaccine. On the other hand identification of structurally stable domains with limited or no polymorphism has led to the development of one candidate tested in phase 1a and 1b clinical trials

Evaluation of the 19 varieties and accessions of tomato against bacterial wilt in Bobo-Dioulasso, Burkina Faso

Bacterial wilt caused by Ralstonia solanacearum E. F. Smith is one of the most harmful phytobacteriosis in the world. The search for varieties resistant or tolerant to this disease is the main method of control. However, there is very little information on tomato accessions and varieties deemed resistant or tolerant to the disease in Burkina Faso, hence the resistance assessment of 19 tomato varieties and accessions in the field in order to improve the productivity of tomatoes in Burkina Faso. With respect to varietal screening, a completely randomized Fisher block was used and agromorphological parameters were evaluated. The evaluation has shown that CRA 66, F1 Platinum, NC72TR4-4, Hawaii 7996, BF-Okitsu and FBT4 are more resistant with respective incidences of 1.25%; 1.25; 1.47%; 2.50%; 2.95% and 4.37%; while L390 was the most sensitive (38.80%). In terms of production, F1 Platinum, F1 Mongal, FBT3 and FBT4 gave the best net yields of 25.85; 25.47; 20.6 and 20.34 tonnes.ha-1. On the other hand, some accessions (CRA66 and BF-Okitsu), which are less sensitive to the pathogen, gave derisory yields. In view of the results obtained, market gardeners in the city of Bobo-Dioulasso can be advised of INERA varieties FBT3 and FBT4 and the F1 Platinum and F1 Mongal hybrids for their good behavior in terms of resistance to the disease and/or of correct yield in infected soils.Keywords: Burkina Faso, R. solanacearum, tomato, varietal resistanc

Diversité et structure des groupements ligneux du parc national d’Arly (Est du Burkina Faso)

The diversity and structure of woody vegetation were studied in the national park of Arly in relation to the ecological conditions. After vegetation classification by DCA analysis, diversity parameters, density, basal area and size class distribution of each plant community were determined. We characterised 10 plant communities whose distribution is governed by a topo-edaphic gradient. The patterns of size class distribution show that the stands of all plant communities are in a stable situation. This result shows the adaptation of the vegetation units to the local environmental conditions as fire regime and soil properties. Woodlands of Tamarindus indica and Combretum paniculatum and riparian forests of Vitex chrysocarpa and Garcinia livingstonei possess the high est density and the highest diversity of tree species. In contrary, wooded grasslands of Euphorbia sudanica and Combretum niorense and humid wooded grasslands of Acacia sieberiana are very poor in species and their density is low. These results supported by correlation analysis show a significant relation between diversity and structure. Topo-edaphic conditions are one of the principal environmental factors which drive the diversity and the structure of plant communities.La présente étude menée sur la végétation ligneuse du parc national d’Arly a pour objectif de caractériser la diversité et la structure des différents groupements végétaux en relation avec les conditions écologiques. 243 relevés phytosociologiques ont été réalisés. Ces relevés font ressortir 109 espèces ligneuses et 10 groupements par la méthode d’analyse DCA. La diversité des groupements végétaux a été caractérisée par le calcul des indices de diversité. Pour chaque groupement ligneux, 10 relevés ont été choisis de manière aléatoire pour des mesures dendrométriques. Les individus dont le diamètre à 1,3 m du sol est supérieur à 5 cm ont été mesurés. La structure des groupements a été décrite à travers la répartition des individus en classe de diamètre, le calcul de la densité et de la surface terrière. La relation entre la diversité et la structure des groupements a été établie sur la base d’analyse de corrélation. Les groupements ligneux distingués sont répartis suivant le gradient topographique. L’analyse de la structure démographique en classe de diamètre montre que les peuplements des différents groupements végétaux sont stables, ce qui traduit leur adaptation aux facteurs écologiques stationnelles telles que le feu et les conditions de sol. Les forêts claires à Tamarindus indica et Combretum paniculatum et les forêts galeries à Vitex chrysocarpa et Garcinia livingstonei sont les formations les plus denses et les groupements ligneux les plus diversifiés. A l’opposé, les savanes arbustives clairsemées à Euphorbia sudanica et Combretum niorense et celles à Acacia sieberiana sont moins denses et constituent les groupements les plus pauvres en espèces. Ainsi, il existe une relation entre la diversité et la structure des groupements des formations ligneuses. Les conditions édaphiques et topographiques occupées par ces groupements expliquent à la fois leur diversité et leur structure

Molecular diagnosis of COVID-19 in Burkina Faso: successful challenge

COVID-19 has worsened the health situation in Burkina Faso. In fact, the country has known a peak of the second wave, which began in November, and ended around January 2021. Biological diagnosis has played a key role in the management of COVID-19. The aim of this review paper is to address the practical aspects that laboratories have faced in order to meet the challenge of SARS-CoV-2 diagnosis in Burkina Faso. According to international requirements, Burkina Faso has used real-time Reverse Transcription Polymerase Chain Reaction (rRT-PCR) as the “gold standard” for the diagnosis of COVID-19. From March 9, 2020 to July 31, 2021, in Burkina Faso, laboratories involved in COVID-19 diagnosis analyzed 226,189 samples by molecular tests and 2, 352 samples by rapid antigenic tests, whose peak was in January 2021 with 35,984 samples analyzed. The daily average rate of samples analysis was 456.02 tests. The majority of the individuals requesting COVID-19 tests were travelers (62.00%), followed by contact cases (18.42%), suspected cases (7.95%), voluntary screening (7.57%), and 4.06% of other applicants consisting of health care personnel and at-risk patients. In terms of prevention, vaccines are being administered to the general population. However, some efforts must be made to provide automated sample analysis equipment and complete sequencing of SARS-CoV-2 remains among the challenges

Etiology and risk factors for meningitis during an outbreak in Batié Health District, Burkina Faso, January-March 2016

Introduction: On 16 March 2016, Batié Health District notified the Burkina Faso Ministry of Health Surveillance unit of 12 suspected cases of meningitis. During the same period, Batié´s neighboring districts in Côte d'Ivoire and Ghana were experiencing a meningitis epidemic. We investigated to establish the etiology and risk factors for the disease and to recommend prevention and control measures. Methods: We conducted unmatched case control study. A case was any person living in Batié with fever (temp. ≥ 38.5°C) and any of the following: neck stiffness, neurological disorder, bulging fontanelle, convulsion during January to April 2016 with cerebrospinal fluid (CSF) positive to PCR. Controls were non sick household members, neighbors or friends to the cases. We analyzed the investigation and laboratory records. We included all confirmed cases and two neighborhood controls per case. We used a standard questionnaire to collect data. We analyzed data by Epi info 7 and calculated odds ratio (ORs),adjusted odds ratios (AOR) and 95% confidence interval. We proceeded to univariate, bivariate, multivariate and logistic regression analysis. Results: We interviewed 93 participants including 31 meningitis cases and 62 controls. The median age of cases was 8 years old [2 months-55 years] and 6.5 years old [5 months-51 years] for controls. Streptococcus pneumoniae 16(51.61%), Neisseria meningitidis W 14(45.16%) and Haemophilus influenzae b 1(3.23%) were the identified germs. The independent risk factors identified were travel to meningitis affected areas (Adjusted odd ratio(AOR)=12[2.3-60],p=0.0029); >5 persons sharing bedroom (AOR=5.7[1.5-22],p=0.012) and rhinopharyngitis (AOR=26[1.8-380],p=0.017). Conclusion: Streptococcus pneumoniae and Neisseria meningitidis W caused the outbreak in Batié. The risk factors were overcrowding, travel to affected areas, and rhinopharyngitis. We recommended reactive vaccination against Neisseria meningitidis W, limited travel to affected areas and ventilation of rooms