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61.
Ilboudo H Jamonneau V Camara M Camara O Dama E Léno M Ouendeno F Courtin F Sakande H Sanon R Kaboré J Coulibaly B N'Dri L Diarra A N'Goran E Bucheton B 《Microbes and infection / Institut Pasteur》2011,13(11):943-952
At a time when human African trypanosomiasis (HAT) elimination again seems a reachable goal in many parts of sub-Saharan Africa, it is becoming increasingly important to characterise the factors involved in disease resurgence or maintenance to develop sustainable control strategies. In this study conducted in the Forecariah mangrove focus in Guinea, HAT patients and serological suspects (SERO) were identified through mass screening of the population with the Card Agglutination Test for Trypanosomiasis (CATT) and were followed up for up to 2 years. Analysis of the samples collected during the follow-up of HAT patients and SERO was performed with PCR (TBR1/TBR2) and the trypanolysis serological test (TL) in order to clarify the role played by these individuals in the epidemiology of HAT. PCR positivity was higher in TL+ than in SERO TL− (50% vs. 18%, respectively). Whereas CATT plasma titres decreased both in treated HAT patients and SERO TL−, SERO TL+ maintained high CATT titres. Four out of 17 SERO TL+ developed HAT during the study. These results strongly suggest that SERO TL+ individuals are asymptomatic carriers. In the context where disease prevalence is sufficiently low, treating SERO TL+ individual may thus be of crucial importance in order to cut transmission. 相似文献
62.
LE Merchant H Rempel T Forge T Kannangara S Bittman P Delaquis E Topp KA Ziebell MS Diarra 《Canadian journal of microbiology》2012,58(9):1084-1098
The objective of this study was to characterize antimicrobial resistance and virulence determinants of Escherichia coli from soil amended with litter from 36-day-old broiler chickens ( Gallus gallus domesticus ) fed with diets supplemented with a variety of antimicrobial agents. Soil samples were collected from plots before and periodically after litter application in August to measure E. coli numbers. A total of 295 E.?coli were isolated from fertilized soil samples between August and March. Antibiotic susceptibility was determined by Sensititre, and polymerase chain reaction was performed to detect the presence of resistance and virulence genes. The results confirmed that E.?coli survived and could be quantified by direct plate count for at least 7 months in soil following litter application in August. The effects of feed supplementation were observed on E.?coli numbers in November and January. Among the 295 E.?coli, the highest antibiotic resistance level was observed against tetracycline and β-lactams associated mainly with the resistance genes tetB and bla(CMY-2), respectively. Significant treatment effects were observed for phylogenetic groups, antibiotic resistance profiles, and virulence gene frequencies. Serotyping, phylogenetic grouping, and pulsed-field gel electrophoresis confirmed that multiple-antibiotic-resistant and potentially pathogenic E.?coli can survive in soil fertilized with litter for several months regardless of antimicrobials used in the feed. 相似文献
63.
Mark A. Travassos Berhane Beyene Zenaw Adam James D. Campbell Nigisti Mulholland Seydou S. Diarra Tassew Kassa Lisa Oot Jenny Sequeira Mardi Reymann William C. Blackwelder Yukun Wu Inna Ruslanova Jaya Goswami Samba O. Sow Marcela F. Pasetti Robert Steinglass Amha Kebede Myron M. Levine 《PloS one》2016,11(3)
Objective
Demographic and health surveys, immunization coverage surveys and administrative data often divergently estimate vaccination coverage, which hinders pinpointing districts where immunization services require strengthening. We assayed vaccination coverage in three regions in Ethiopia by coverage surveys and linked serosurveys.Methods
Households with children aged 12–23 (N = 300) or 6–8 months (N = 100) in each of three districts (woredas) were randomly selected for immunization coverage surveys (inspection of vaccination cards and immunization clinic records and maternal recall) and linked serosurveys. IgG-ELISA serologic biomarkers included tetanus antitoxin ≥ 0.15 IU/ml in toddlers (receipt of tetanus toxoid) and Haemophilus influenzae type b (Hib) anti-capsular titers ≥ 1.0 mcg/ml in infants (timely receipt of Hib vaccine).Findings
Coverage surveys enrolled 1,181 children across three woredas; 1,023 (87%) also enrolled in linked serosurveys. Administrative data over-estimated coverage compared to surveys, while maternal recall was unreliable. Serologic biomarkers documented a hierarchy among the districts. Biomarker measurement in infants provided insight on timeliness of vaccination not deducible from toddler results.Conclusion
Neither administrative projections, vaccination card or EPI register inspections, nor parental recall, substitute for objective serological biomarker measurement. Including infants in serosurveys informs on vaccination timeliness. 相似文献64.
65.
Renata Servan de Almeida Saliha Hammoumi Patricia Gil Fran?ois-Xavier Briand Sophie Molia Nicolas Gaidet Julien Cappelle Véronique Chevalier Gilles Balan?a Abdallah Traoré Colette Grillet Olivier Fridolin Maminiaina Samia Guendouz Marthin Dakouo Kassim Samaké Ould El Mamy Bezeid Abbas Diarra Hassen Chaka Flavie Goutard Peter Thompson Dominique Martinez Véronique Jestin Emmanuel Albina 《PloS one》2013,8(10)
Newcastle disease (ND) is one of the most lethal diseases of poultry worldwide. It is caused by an avian paramyxovirus 1 that has high genomic diversity. In the framework of an international surveillance program launched in 2007, several thousand samples from domestic and wild birds in Africa were collected and analyzed. ND viruses (NDV) were detected and isolated in apparently healthy fowls and wild birds. However, two thirds of the isolates collected in this study were classified as virulent strains of NDV based on the molecular analysis of the fusion protein and experimental in vivo challenges with two representative isolates. Phylogenetic analysis based on the F and HN genes showed that isolates recovered from poultry in Mali and Ethiopia form new groups, herein proposed as genotypes XIV and sub-genotype VIf with reference to the new nomenclature described by Diel’s group. In Madagascar, the circulation of NDV strains of genotype XI, originally reported elsewhere, is also confirmed. Full genome sequencing of five African isolates was generated and an extensive phylogeny reconstruction was carried out based on the nucleotide sequences. The evolutionary distances between groups and the specific amino acid signatures of each cluster allowed us to refine the genotype nomenclature. 相似文献
66.
Cosma D. Dellisanti Borna Ghosh Susan M. Hanson James M. Raspanti Valerie A. Grant Gaoussou M. Diarra Abby M. Schuh Kenneth Satyshur Candice S. Klug Cynthia Czajkowski 《PLoS biology》2013,11(11)
Pentameric ligand-gated ion channels (pLGICs) are neurotransmitter-activated receptors that mediate fast synaptic transmission. In pLGICs, binding of agonist to the extracellular domain triggers a structural rearrangement that leads to the opening of an ion-conducting pore in the transmembrane domain and, in the continued presence of neurotransmitter, the channels desensitize (close). The flexible loops in each subunit that connect the extracellular binding domain (loops 2, 7, and 9) to the transmembrane channel domain (M2–M3 loop) are essential for coupling ligand binding to channel gating. Comparing the crystal structures of two bacterial pLGIC homologues, ELIC and the proton-activated GLIC, suggests channel gating is associated with rearrangements in these loops, but whether these motions accurately predict the motions in functional lipid-embedded pLGICs is unknown. Here, using site-directed spin labeling (SDSL) electron paramagnetic resonance (EPR) spectroscopy and functional GLIC channels reconstituted into liposomes, we examined if, and how far, the loops at the ECD/TMD gating interface move during proton-dependent gating transitions from the resting to desensitized state. Loop 9 moves ∼9 Å inward toward the channel lumen in response to proton-induced desensitization. Loop 9 motions were not observed when GLIC was in detergent micelles, suggesting detergent solubilization traps the protein in a nonactivatable state and lipids are required for functional gating transitions. Proton-induced desensitization immobilizes loop 2 with little change in position. Proton-induced motion of the M2–M3 loop was not observed, suggesting its conformation is nearly identical in closed and desensitized states. Our experimentally derived distance measurements of spin-labeled GLIC suggest ELIC is not a good model for the functional resting state of GLIC, and that the crystal structure of GLIC does not correspond to a desensitized state. These findings advance our understanding of the molecular mechanisms underlying pLGIC gating. 相似文献
67.
Fatima Zohra Hamlili Fatou Thiam Maureen Laroche Adama Zan Diarra Souleymane Doucour Papa Mouhamadou Gaye Cheikh Binetou Fall Babacar Faye Cheikh Sokhna Doudou Sow Philippe Parola 《PLoS neglected tropical diseases》2021,15(9)
Freshwater snails of the genera Biomphalaria, Bulinus, and Oncomelania are intermediate hosts of schistosomes that cause human schistosomiasis, one of the most significant infectious neglected diseases in the world. Identification of freshwater snails is usually based on morphology and potentially DNA-based methods, but these have many drawbacks that hamper their use. MALDI-TOF MS has revolutionised clinical microbiology and has emerged in the medical entomology field. This study aims to evaluate MALDI-TOF MS profiling for the identification of both frozen and ethanol-stored snail species using protein extracts from different body parts. A total of 530 field specimens belonging to nine species (Biomphalaria pfeifferi, Bulinus forskalii, Bulinus senegalensis, Bulinus truncatus, Bulinus globosus, Bellamya unicolor, Cleopatra bulimoides, Lymnaea natalensis, Melanoides tuberculata) and 89 laboratory-reared specimens, including three species (Bi. pfeifferi, Bu. forskalii, Bu. truncatus) were used for this study. For frozen snails, the feet of 127 field and 74 laboratory-reared specimens were used to validate the optimised MALDI-TOF MS protocol. The spectral analysis yielded intra-species reproducibility and inter-species specificity which resulted in the correct identification of all the specimens in blind queries, with log-score values greater than 1.7. In a second step, we demonstrated that MALDI-TOF MS could also be used to identify ethanol-stored snails using proteins extracted from the foot using a specific database including a large number of ethanol preserved specimens. This study shows for the first time that MALDI-TOF MS is a reliable tool for the rapid identification of frozen and ethanol-stored freshwater snails without any malacological expertise. 相似文献
68.
Seasonal decline of the tomato leafminer,Tuta absoluta,in the shifting landscape of a vegetable‐growing area 下载免费PDF全文
Serigne Sylla Oumar Seydi Karamoko Diarra Thierry Brévault 《Entomologia Experimentalis et Applicata》2018,166(8):638-647
Insect pest populations exhibit seasonal dynamics in response to changes in resource availability or other environmental factors such as climatic conditions, natural enemies, and intra‐ or interspecific competition. Understanding such dynamics is critical for developing effective integrated pest management strategies. The objective of the present study was to identify factors driving the seasonal decline of the tomato leafminer, Tuta absoluta (Meyrick) (Lepidoptera: Gelechiidae), in the shifting landscape of a vegetable‐growing area in Senegal. A set of 42 tomato fields was monitored for the number of T. absoluta adults caught in pheromone traps and for the incidence of larvae, during 5 months from June to November 2016 in the Niayes area (Senegal). The surface of solanaceous host crops, climatic conditions, and abundance of natural enemies were also monitored. A drastic decline in T. absoluta abundance was observed during the rainy season. The decrease in resource availability, especially tomato crops, in the surrounding landscape of monitored fields was the main factor affecting the population dynamics during the rainy season. However, alternative host crops such as eggplant and Ethiopian eggplant, can provide ‘reservoirs’ for residual populations of the pest. For applied purpose, it would be interesting to focus the management efforts on residual populations during the rainy season, to make more difficult the reconstitution of populations during the dry season. 相似文献
69.
Alphonse Ouédraogo Alfred B. Tiono Amidou Diarra Souleymane Sanon Jean Baptiste Yaro Esperance Ouedraogo Edith C. Bougouma Issiaka Soulama Adama Gansané Amathe Ouedraogo Amadou T. Konate Issa Nebie Nora L. Watson Megan Sanza Tina J. T. Dube Sodiomon Bienvenu Sirima 《PloS one》2013,8(1)
Background
Malariometric parameters are often primary endpoints of efficacy trials of malaria vaccine candidates. This study aims to describe the epidemiology of malaria prior to the conduct of a series of drug and vaccine trials in a rural area of Burkina Faso.Methods
Malaria incidence was prospectively evaluated over one year follow-up among two cohorts of children aged 0–5 years living in the Saponé health district. The parents of 1089 children comprising a passive case detection cohort were encouraged to seek care from the local health clinic at any time their child felt sick. Among this cohort, 555 children were randomly selected for inclusion in an active surveillance sub-cohort evaluated for clinical malaria during twice weekly home visits. Malaria prevalence was evaluated by cross-sectional survey during the low and high transmission seasons.Results
Number of episodes per child ranged from 0 to 6 per year. Cumulative incidence was 67.4% in the passive and 86.2% in the active cohort and was highest among children 0–1 years. Clinical malaria prevalence was 9.8% in the low and 13.0% in the high season (p>0.05). Median days to first malaria episode ranged from 187 (95% CI 180–193) among children 0–1 years to 228 (95% CI 212, 242) among children 4–5 years. The alternative parasite thresholds for the malaria case definition that achieved optimal sensitivity and specificity (70–80%) were 3150 parasites/µl in the high and 1350 parasites/µl in the low season.Conclusion
Clinical malaria burden was highest among the youngest age group children, who may represent the most appropriate target population for malaria vaccine candidate development. The pyrogenic threshold of parasitaemia varied markedly by season, suggesting a value for alternative parasitaemia levels in the malaria case defintion. Regional epidemiology of malaria described, Sapone area field centers are positioned for future conduct of malaria vaccine trials. 相似文献70.
Malik Coulibaly Nicolas Meda Caroline Yonaba Sylvie Ouedraogo Malika Congo Mamoudou Barry Elisabeth Thio Issa Siribié Fla Koueta Diarra Ye Ludovic Kam Stéphane Blanche Phillipe Van De Perre Valériane Leroy MONOD Study Group ANRS 《PloS one》2014,9(10)