Diversité, nuisances et modes de gestion des termites (Isoptera) dans les agrosystèmes sénégalais

Ce travail présente la première liste des espèces de termites recensées, une revue de la littérature de leurs dégâts sur les essences botaniques et leurs modes de gestion dans les agrosystèmes au Sénégal entre 1966 et 2015. Elle a été faite sur la base d’une revue bibliographique existante et complétée par un récent inventaire dans 45 vergers. Au total, 90 espèces de termites sont recensées dont 54 sont rencontrées dans les vergers. La répartition de ces espèces est tributaire des conditions climatiques et édaphiques. Il est possible que cette diversité, relativement élevée, ait été sous-estimée à cause des difficultés liées à l’identification de certaines espèces de termites et à la faiblesse des inventaires dans certaines localités géographiques. Les récents inventaires dans les vergers ont d’ailleurs permis de signaler une nouvelle espèce, Amitermes guineensis précédemment signalée dans les jachères. Les termites champignonnistes et les xylophages sont dominants dans les vergers et 45 sur les 54 recensés dans les verges s’attaquent aux arbres fruitiers. Les termites causent des dégâts plus ou moins importants sur plusieurs essences botaniques. Leurs méthodes de gestion sont diverses et variées et l’efficacité de certaines d’entre elles doit être étudiée afin de promouvoir les plus efficaces.© 2016 International Formulae Group. All rights reserved.Mots clés: Termite, biodiversité, essence botanique, dégâts, méthode de gestion, vergersEnglish Title: Diversity, damages and management of termites (Isoptera) in Senegalese agrosystemsEnglish AbstractThis work presents the first species list of termites of Senegal based on a review of the literature the plants they cause damage and the methods of their management in Senegalese agroecosystems from 1966 to 2015. It was carried out based on a bibliographic review completed by a recent survey in 45 orchards. In sum, 90 termite species are recorded and 54 were collected in orchards based agroecosystems. The distribution of termite species is related to climatic and edaphic conditions. It might be possible that this high diversity of termites is under-estimated because of difficulties for identification of some species and the weak of the surveys in some geographic localities. The recent orchard surveys have more over allowed to signal a new species, Amitermes guineensis previously known in laying fallows. Mushroom grower termites and xylophagous termites are dominant in orchards and 45 species out of 54 are known as crop tree pests in orchards. Termites are responsible of important damages of a lot of botanical species. There are several and various management methods to termite pest species and the efficacy of some of them must be further studied in order to promote the better ones.© 2016 International Formulae Group. All rights reserved.Keywords: Termite, biodiversity, botanical species, damage, management methods, orchard

Evaluation of antimycobacterial activity of medicinal plants used by Malian traditional medicine practitioners to treat tuberculosis

Global Tuberculosis (TB) control is facing major challenges such as occurrence of multidrug-resistant (MDR) and extensively drug-resistant tuberculosis (XDR). The current TB drugs are getting less effective and associated with side effects limiting their use, especially with MDR and XDR infected patients. In Mali, many medicinal plants are used against various diseases including bacterial infections. The study aimed at studying the antimycobacterial activities of 60 extracts from 22 Malian medicinal. The antibacterial activity against Mycobacterium tuberculosis H37Rv was assessed employing micro-broth dilution method. Out of 60 extracts evaluated, eleven from nine different plants were found to be active against H37Rv strain. The minimal inhibitory concentrations (MICs) ranked from 125 μg/mL to 1250 μg/mL. The most active extracts (125 μg/mL) were represented by ethanolic extract of Saba senegalensis and Vitellaria paradoxa leaves, dichloromethane extract of Cola cordifolia leaves, Strychnos spinosa and Ximenia Americana roots. Ethanolic extract of Zizyphus mauritiana, Guiera senegalensis and methanolic extract of Anthocleista djalonensis also prevented the growth of H37Rv at 250 μg/mL. The results suggest that Saba senegalensis, Vitellaria paradoxa, Cola cordifolia, Strychnos spinosa and Ximenia Americana could be potential sources of antimycobacterial molecule

Evolution of Mycobacterium tuberculosis complex lineages and their role in an emerging threat of multidrug resistant tuberculosis in Bamako, Mali

In recent years Bamako has been faced with an emerging threat from multidrug resistant TB (MDR-TB). Whole genome sequence analysis was performed on a subset of 76 isolates from a total of 208 isolates recovered from tuberculosis patients in Bamako, Mali between 2006 and 2012. Among the 76 patients, 61(80.3%) new cases and 15(19.7%) retreatment cases, 12 (16%) were infected by MDR-TB. The dominant lineage was the Euro-American lineage, Lineage 4. Within Lineage 4, the Cameroon genotype was the most prevalent genotype (n = 20, 26%), followed by the Ghana genotype (n = 16, 21%). A sub-clade of the Cameroon genotype, which emerged ~22 years ago was likely to be involved in community transmission. A sub-clade of the Ghana genotype that arose approximately 30 years ago was an important cause of MDR-TB in Bamako. The Ghana genotype isolates appeared more likely to be MDR than other genotypes after controlling for treatment history. We identified a clade of four related Beijing isolates that included one MDR-TB isolate. It is a major concern to find the Cameroon and Ghana genotypes involved in community transmission and MDR-TB respectively. The presence of the Beijing genotype in Bamako remains worrying, given its high transmissibility and virulence

Diagnostic accuracy of Xpert® MTB/RIF Ultra for childhood tuberculosis in West Africa - a multicentre pragmatic study

OBJECTIVE: To evaluate the performance of Xpert MTB/RIF Ultra ('Ultra') for diagnosis of childhood tuberculosis (TB) within public health systems. METHODS: In this cross-sectional study, children aged <15 years with presumptive pulmonary TB were consecutively recruited and evaluated for TB at tertiary-level hospitals in Benin, Mali and Ghana. Bivariate random-effects models were used to determine the pooled sensitivity and specificity of Ultra against culture. We also estimated its diagnostic yield against a composite microbiological reference standard (cMRS) of positive culture or Ultra. RESULTS: Overall, 193 children were included in the analyses with a median (IQR) age of 4.0 (1.1 - 9.2) years, 88 (45.6%) were female, and 36 (18.7%) were HIV-positive. Thirty-one (16.1%) children had confirmed TB, 39 (20.2%) had unconfirmed TB, and 123 (63.7%) had unlikely TB. The pooled sensitivity and specificity of Ultra verified by culture were 55.0% (95% CI: 28.0 - 79.0%) and 95.0% (95% CI: 88.0 - 98.0%), respectively. Against the cMRS, the diagnostic yield of Ultra and culture were 67.7% (95% CI: 48.6 - 83.3%) and 70.9% (95% CI: 51.9 - 85.8%), respectively. CONCLUSION: Ultra has suboptimal sensitivity in children with TB that were investigated under routine conditions in tertiary-level hospitals in three West African countries

Failure to Recognize Nontuberculous Mycobacteria Leads to Misdiagnosis of Chronic Pulmonary Tuberculosis

BACKGROUND: Nontuberculous mycobacterial (NTM) infections cause morbidity worldwide. They are difficult to diagnose in resource-limited regions, and most patients receive empiric treatment for tuberculosis (TB). Our objective here is to evaluate the potential impact of NTM diseases among patients treated presumptively for tuberculosis in Mali. METHODS: We re-evaluated sputum specimens among patients newly diagnosed with TB (naïve) and those previously treated for TB disease (chronic cases). Sputum microscopy, culture and Mycobacterium tuberculosis drug susceptibility testing were performed. Identification of strains was performed using molecular probes or sequencing of secA1 and/or 16S rRNA genes. RESULTS: Of 142 patients enrolled, 61 (43%) were clinically classified as chronic cases and 17 (12%) were infected with NTM. Eleven of the 142 (8%) patients had NTM disease alone (8 M. avium, 2 M. simiae and 1 M. palustre). All these 11 were from the chronic TB group, comprising 11/61 (18%) of that group and all were identified as candidates for second line treatment. The remaining 6/17 (35.30%) NTM infected patients had coinfection with M. tuberculosis and all 6 were from the TB treatment naïve group. These 6 were candidates for the standard first line treatment regimen of TB. M. avium was identified in 11 of the 142 (8%) patients, only 3/11 (27.27%) of whom were HIV positive. CONCLUSIONS: NTM infections should be considered a cause of morbidity in TB endemic environments especially when managing chronic TB cases to limit morbidity and provide appropriate treatment

Host-Directed Therapies for tackling Multi-Drug Resistant TB – learning from the Pasteur-Bechamp debates

Tuberculosis (TB) remains a global emergency causing an estimated 1.5 million deaths annually. For several decades the major focus of TB treatment has been on antibiotic development targeting Mycobacterium tuberculosis (M.tb). The lengthy TB treatment duration and poor treatment outcomes associated with multi-drug resistant TB (MDR-TB) are of major concern. The sparse new TB drug pipeline and widespread emergence of MDR-TB signal an urgent need for more innovative interventions to improve treatment outcomes. Building on the historical Pasteur-Bechamp debates on the role of the ‘microbe’ versus the ‘host internal milieu’ in disease causation, we make the case for parallel investments into host-directed therapies (HDTs). A range of potential HDTs are now available which require evaluation in randomized controlled clinical trials as adjunct therapies for shortening the duration of TB therapy and improving treatment outcomes for drug-susceptible TB and MDR-TB. Funder initiatives that may enable further research into HDTs are described

Towards host-directed therapies for tuberculosis

The treatment of tuberculosis is based on combinations of drugs that directly target Mycobacterium tuberculosis. A new global initiative is now focusing on a complementary approach of developing adjunct host-directed therapies. Despite the availability of effective antibiotics for tuberculosis (TB) for the past half century, it remains an important global health problem; there are ~9 million active TB cases and ~1.5 million TB-induced deaths per year (see the World Health Organization (WHO) Global Tuberculosis Report in Further information). Health services around the world face major barriers to achieving optimal outcomes from current TB treatment regimens. These barriers include: the spread of multidrug-resistant TB (MDR-TB) and extensively drug-resistant TB (XDR-TB); complex and toxic treatment regimens for MDR-TB; HIV co-infection; pharmacokinetic interactions between TB drugs and antiretroviral drugs; relapse; permanent damage to lung and other tissues; long-term functional disability; immune reconstitution inflammatory syndrome (IRIS); and co-morbidity with non-communicable diseases such as diabetes and chronic obstructive airway diseases. Another fundamental problem is the long duration of TB drug treatment (6 months for drug-sensitive TB and at least 18 months for drug-resistant TB) to achieve a cure, owing to the presence of dormant Mycobacterium tuberculosis bacilli that are phenotypically resistant to current classes of anti-TB drugs, which can only target bacterial replication. There is therefore an urgent need for new TB treatments. However, the TB drug pipeline is thin1, 2. For the past 60 years, efforts to develop new treatments have focused on compounds and regimens that target M. tuberculosis directly. Recently, however, attention has focused on investigating a range of adjunct treatment interventions known as host-directed therapies (HDTs) that instead target the host response to infection. Here, we highlight the rationale for HDTs, the current portfolio of HDTs and their mechanisms of action, and a consortium-based approach to drive forward their evaluation in clinical trials