Strength development and self-desiccation of saline cemented paste backfill

Given that many mines around the world are located in areas where fresh water is scarce, and companies are being held to increasingly stringent sustainability and environmental responsibility standards, many mines are looking to use locally available saline groundwater or seawater as mixing water in cemented paste backfill (CPB). However, the impacts of this decision on key engineering properties of CPB (e.g. strength and self-desiccation) that affect its mechanical stability need to be better understood to allow confident selection of this practical and more sustainable solution. Thus, the effect of mixing water salinity and binder type on the strength (unconfined compressive strength, UCS) development and self-desiccation (measured by suction and volumetric water content) of CPB is explored in this research. NaCl concentrations from 0 to 300 g/L were used in CPB made with silica tailings and Portland cement type I (PC). Concentrations of 10 and 35 g/L were found to moderately increase UCS, while a concentration of 100 g/L had comparable UCS to non-saline CPB and a concentration of 300 g/L was found to significantly decrease UCS over all curing times. The overall trend is 10 g/L > 35 g/L > 0 g/L > 100 g/L > 300 g/L. The UCS of the 60-day-old CPB with a NaCl of 300 g/L is significantly lower, registering a 26% decrease compared to the UCS of the 60-day-old CPB without salt. In contrast, the UCS of the 60-day-old CPBs containing 10 g/L and 35 g/L of salt exhibits a notable improvement, being 15% and 10% higher, respectively, than the UCS of the 60-day-old CPB without salt. Water content and suction monitoring were conducted up to 28 days of curing time, and it was found that suction only slightly contributed to UCS gain of the saline CPB, and high salt contents (100 and 300 g/L) significantly inhibited the self-desiccation ability of CPB due to inhibition of cement hydration by the excessive amount of salt. The increase in strength of both saline and non-saline samples was attributed primarily to the increase in cement hydration products, while the increased strength of the samples with salinities of 10 and 35 g/L was mainly attributed to the enhancement of the binder hydration due to the low amount of salt and the presence of Friedel's salt in the pores. The effect of PC replacement by 25 to 75% with slag on CPB with 35 g/L mixing water salinity was also studied. Slag replacement of 50% and higher resulted in significantly higher UCS over most curing times. Suction likely moderately contributed to UCS of the saline CPB with slag, in addition to the presence of Friedel's salt in the pores and the acceleration of cement and slag hydration by the presence of NaCl.

First report of Alstroemeria necrotic streak virus infecting greenhouse bell pepper (Capsicum annuum) in Canada

Alstroemeria necrotic streak virus (ANSV) is an Orthotospovirus that has been isolated from symptomatic Alstroemeria plant in 2010 (Hassani-Mehraban et al. 2010). It has been shown to infect crops of bell pepper (Capsicum annuum) and tomato (Solanum lycopersicum) (Olaya et al. 2017) which are two of the three biggest greenhouse crops in Canada in terms of production volume and value (Statistic Canada. 2020). In July of 2022, the entire production of bell pepper (all plants) from a greenhouse in Québec was presenting necrotic rings and discoloration in fruit and seemingly healthy leaves. Samples from these infected bell pepper were found to be negative for twenty two common viruses infecting bell pepper by ELISA immunoassay by the Laboratoire d'expertise et de diagnostic en phytoprotection (LEDP) (Québec, Canada). To identify the causal agent, double-stranded RNA was extracted from leaf and fruit of one plant to form two separate samples (leaf and fruit) and used for cDNA library preparations with Nextera XT DNA Sample Prep kit (Illumina, USA). The libraries were sequenced using Illumina Miseq (Fall et al. 2020). The same dsRNA were also sequenced with MinION nanopore sequencing method as described previously (Javaran et al. 2021; Javaran et al. 2023). The obtained raw FASTQ data were processed following the methodology described in Fall et al. 2020 and Javaran et al. 2023. The Miseq sequencing yielded over 2 million reads per sample with a percentage of mapped viral reads ranging from 26.92 to 47.29% of the total number of reads. The leaf samples were positive to Bell pepper endornavirus (BPEV) with the full genome covered 16713 times and Alstroemeria necrotic streak virus (ANSV) with 98% of the genome covered 4929 times. The MinION sequencing yielded 1,028,460 reads and the same viruses were detected with 1288 long reads (mean length of 745bp) assigned to ANSV genome. Both viruses were detected in the leaf and fruit samples. The complete ANSV genome comprising three segments (L, M, and S) was assembled and deposited in GenBank: (OQ261731-OQ261733). These L, M and S segments shown 99% nt identity with an isolate from the Columbia (GenBank: MF469036, MF469037, MF469038). It is interesting that read coverage at near the 2000th position of the S segment, was very low. This phenomenon may suggest a cleavage site nearby by a viral or host factor. ANSV was mainly found in leaf samples and very low numbers of reads in fruit samples. The presence of ANSV was confirmed by RT-PCR using the primers specific to the ANSV nucleocapsid gene Tospo_S_F (5'- CAG AAT CAG GCT GCA TTT AAT TTC C-3') and Tospo_S_R (5'-CAA CGC TTC CTT TAG CAT TAG G-3') (Gallo et al. 2019). The sequences of ∼600 bp amplicons were determined using Sanger sequencing and showed 100% nt identity with Miseq-derived sequences of ANSV. The virus has previously been detected in Colombia (Hassani-Mehraban et al. 2010) and then in California in 2018 (Tian et al. 2020). This is to our knowledge the first detection of ANSV in Canada. Bell pepper is one of the most important crops in Canada and the ANSV vector, the western flower thrips (Frankliniella occidentalis), known to spread the tomato spotted wilt virus (TSWV) is established in Canada (Allen et al. 1986). The detection of ANSV in Canada is line with the hypothesis of an international spread of this virus (Tian et al. 2020) as is it not known to spread through seeds.

Household level of air pollution and its impact on the occurrence of Acute Respiratory Illness among children under five: secondary analysis of Demographic and Health Survey in West Africa

BACKGROUND

One out of ten deaths of children under five are attributable to indoor air pollution. And Acute Respiratory Illness (ARI) is among the direct causes.

OBJECTIVE

This study showed the possibilities of characterizing indoor air pollution in West African Economic and Monetary Union (WAEMU) area and it also made it possible to estimate its impact on the occurrence of ARI in children under five.

METHODS

It has been a secondary analysis based on Demographic and Health Surveys (DHSs) from WAEMU countries' data.. "Household level of air pollution" is the created composite variable, from questions on the degradation factors of indoor air quality (domestic combustion processes) which served to characterize indoor air pollution and to measure its impact by a logistic regression.

RESULTS

Burkina Faso stands out with a greater number of households with a high level of pollution (63.7%) followed by Benin (43.7%) then Togo (43.0%). The main exposure factor "Household level of air pollution" was associated with ARI symptoms (Togo: prevalence = 51.3%; chi-squared test's p-value < 0.001). Exposure to high level of pollution constitutes a risk (AOR [95 CI]), even though it is not significant ( Ivory Coast: 1.29 [0.72-2.30], Senegal: 1.39 [0.94-2.05] and Togo: 1.15 [0.67-1.95]) and this could be explained by the high infectious etiology of the ARI.

Assessment of the global toxicity of marine sediments from the Dakar peninsula (Senegal, West Africa)

Marine pollution in West Africa is major threat particularly around coastal megacities. We assess the chemical and ecotoxicological quality of the marine sediments in various submerged sampling sites of Dakar. Analysis revealed that sediments were slightly basic in which fine and coarse sands predominated. High percentages of total organic carbon were found sometime above 6%. Higher levels of heavy metal were reported than in previous studies. Chromium and nickel were above the Probable Effect Concentration. Low trophic level appeared not affected by the overall toxicity, while medium trophic level was more affected. Indeed, the vast majority (91%) of sites studied revealed a net percentage of Magallana gigas embryolarval developmental abnormality over 20%. The assessment of the global toxicity of marine sediments from the Dakar sites Studied (n = 11) seemed, almost, as a whole, to be in a poor ecotoxicological state calling to take measures to improve the sanitary condition of this marine feature.

Water, sanitation, and hygiene access in Senegal and its impact on the occurrence of diarrhea in children under 5 years old

Diarrheal diseases are the second leading cause of child mortality worldwide, occurring in about one in every nine child deaths, and were associated with water, sanitation, and hygiene (WASH) access. In this study, we provided an overview of WASH indicators' evolution from 2000 to 2017 and their impact on the occurrence of diarrhea in children under 5 years old in Senegal. It was a retrospective cross-sectional study, in which we did a secondary analysis of data from the Joint Monitoring Program (JMP) for water supply and sanitation and from the Senegal Demographic and Health Survey 2018. Our results showed that access to safely managed services increased by 18.1 and 19.1%, respectively, for water and sanitation. The prevalence of diarrhea estimated at 18.16% was associated with straining water through a cloth (adjusted odds ratio (AOR) [95% confidence interval (CI)]: 1.21 [1.00-1.45]) and getting water supplies from a source not located in a dwelling (AOR [95% CI]: 1.59 [1.21-2.09]). The prevalence of diarrhea among children under 5 years old was still relatively high in Senegal and was significantly associated with a lack of WASH access. Although the latter continues to increase, additional efforts to make water safer to drink will significantly reduce the occurrence of diarrheal diseases among children under 5 years old in Senegal.

Investigating the metal contamination status from recycling e-waste sites from Dakar, Senegal

In Senegal, processes employed for recycling e-wastes result in release of so-called heavy metals in the environment. In this study, the metal distribution and concentrations of soils collected from four e-waste recycling areas located in the Dakar area are presented. Measurements are performed using portable X-ray fluorescence and laser-induced breakdown spectroscopy (LIBS) to obtain a complete analysis of the soil, including major and trace elements (i.e., mg/kg). Levels of zinc, copper, manganese, and iron in soils are high but contrasted ranging from 66 mg/kg for Cu in Mbeubeuss landfill to more than 1000 mg/kg for Mn and 10,000 mg/kg for Zn. Lower values are obtained for chromium and lead (Cr = 207 mg/kg and Pb = 181 mg/kg). The most elevated average lead values (i.e., 2935 mg/kg and 1427 mg/kg) are obtained from the e-waste recycling sites located in the urban area of Dakar: Reubeuss and Pikine, respectively. Specific element fingerprints are obtained from each of the studied areas. To evaluate human exposure to the main metals, vegetables grown outside the large e-waste landfill were analyzed. The values obtained for Cr, Cu, Fe, Mn, Sr, and Zn are low, ranging from 0.11 to 9.66 mg/kg for chromium in turnip and iron in beetroots, respectively. The calculated health risk index remains below unit for all vegetables, which means no potential risk of vegetable consumption for human health. The data provided useful information to estimate contaminations and their origin. Therefore, in order to ensure food safety, continuous monitoring of the vegetables grown in the vicinity of recycling areas is needed.

Speciation of metals by sequential extractions of agricultural soils located near a dumpsite for prediction of element availability to vegetables

In this paper heavy metal pollution has been investigated by comparing total concentrations and speciation of heavy metals (Cr, Cu, Mn, Zn, Pb and Sr) in soils from four agricultural fields (S1, S2, S3, S4) located in the direct vicinity of the largest landfill in Senegal. The sequential test allowed discriminating between various fractions of heavy metals, namely the acid-extractable fraction, the fraction bound to Fe oxides, the fraction bound to organic matter and the residual fraction. It was proven that the most important fractions of metals (Cr, Cu, Pb, Mn, Sr and Zn) are bound to the residual fraction, more than 50% for most sites, and thus they may be relatively hardly liberated into the environment. The results also showed that the metal pollution in S3 and S4 were more severe than in other sampling sites, especially for Mn and Zn. In addition, the exchangeable fraction, which is the most available, represents from 10 to 47% of the total concentration for Sr, Mn and Zn, indicating that a non-negligible part of these elements may be easily released. Matrix correlation between soil characteristics and the elemental concentrations was tested to study and to detect a possible trend of metal mobilization from organic matter or oxides to agricultural soils. Vegetable grown from the four sampling sites were analyzed, Cr, Zn and Pb concentrations were high in many studied foodstuffs, (up to 54 mg/kg; 45.8 mg/kg and 3.4 mg/kg for Mn, Zn and Pb respectively) and higher than the threshold values of FAO/WHO. Calculation of hazard indexes suggested no potential health risks associated with consuming the vegetables with the exception of cassava and cassava leaves.

Dynamic response of thickened tailings in shaking table testing

In this study, an instrumented thickened tailings deposit model was designed, built and employed to evaluate the behaviour of layered thickened tailings to dynamic loading by using a shaking table equipment. The thickened tailings were deposited subsequently in three thin layers in a flexible laminar shear box mounted on top of the shaking table. Cyclic loading with a peak horizontal acceleration of 0.13 g and a frequency of 1 Hz was applied to the layered tailings deposit. Different types of sensors were placed to monitor the accelerations, displacements, volumetric water content and pore water pressures at the intermediate depth of each layer. Results indicated that the acceleration for the bottom and middle layers were similar to that of the base of the shaking table; but, this was not the case for the top layer. The measurements of vertical displacements indicated that all layers of thickened tailings experienced initially contraction and subsequently dilation during the shaking. The excess pore water pressure ratios were found to exceed unity through all layers of thickened tailings when the shaking ended. In other words, the results showed that the layered thickened tailings are susceptible to liquefaction under the considered testing conditions. It is also found that upward pore water migration to the top layer and downward pore water flow to the bottom layer occurred in the thickened tailings deposit. This water migration generated additional pore water pressure and also impacted the vertical displacement and liquefaction susceptibility of the thickened tailings material. The results of this study give a better understanding of the dynamic behaviour of thickened tailings, which is crucial for the safety of thickened tailings systems as well as sustainable mining.

Physicochemical factors affecting the diversity and abundance of Afrotropical Culicoides species in larval habitats in Senegal

Biting midges of the genus Culicoides (Diptera: Ceratopogonidae) are the biological vectors of arboviruses of global importance in animal health. We characterized the physicochemical parameters that determine the density and composition of the main Culicoides species of veterinary interest in larval habitats of the Niayes region of Senegal. For this purpose, we combined larval and substrate sampling in the field in different habitat types with adult emergence and physicochemical analyses in the laboratory. Three major habitat types were identified, conditioning the predominant species of Culicoides and pH and the amount of organic matter were positively correlated with the abundance of larvae and emerging Culicoides, as opposed to salinity. The diversity of emerging Culicoides was positively correlated with pH while it was negatively correlated with salinity. Culicoides distinctipennis was the predominant species in the larval habitat group of freshwater lake edges. In the larval habitat group of pond and puddle edges, C. oxystoma and C. nivosus were predominant; both species were again most abundant in the larval habitat group of saltwater lake edges. These variabilities in physicochemical parameters support the distribution of different Culicoides species in different habitat groups. These results make it possible to implement effective, selective and environmental-friendly control measures but also to improve current models for estimating the abundance of adult vector populations at a local scale.

First report of Grapevine yellow speckle viroid 1 infecting grapevine (Vitis vinifera L.) in Canada

Quebec is the third largest wine grape producer in Canada in acreage, tonnage, and wine grape sales (Carisse et al. 2017; Ben Moussa et al. 2019). To evaluate the diversity of viruses infecting grapevine in Quebec, a total of 77 leaf tissue samples (cv. Vidal) were collected from July to October in 2020 in three different vineyards located in Frelighsburg, Hemmingford and Saint-Jacques-le-Mineur in Quebec, Canada. Double-stranded RNA was extracted from each sample and used for cDNA library preparation with the Nextera XT DNA Library Preparation Kit (Illumina) as described previously (Kesanakurti et al. 2016). High-throughput sequencing (HTS, 2x300 bp) was conducted on dual-indexed libraries in a v3 flow cell using the Illumina MiSeq platform (Adkar-Purushothama et al. 2020). The obtained raw FASTQ data was de-multiplexed into 154 separate sequence files, and the adapters and barcode sequences were trimmed. The quality of the sequences was verified using Trimmomatic V.0.32 and the "clean" sequences were analyzed using Virtool and VirFind virus detection pipelines described elsewhere (Ho and Tzanetakis 2014; Rott et al. 2017) to screen for all possible viruses in the databases. Over 100,000 reads per sample were obtained with a percentage of mapped viral reads ranging from 1.47 to 19.43% of total number of reads. Out of 77 samples, 16 revealed the sequence of grapevine yellow speckle viroid 1 (GYSVd-1), for which the length coverage ranged from 98.5 to 99.1%; the depth ranged from 2X to 856X. The GYSVd-1 positive sequence files were subjected to whole genome assembly on CLC genomics Workbench v20.0.4 with the isolate SY-BR from Brazil (KU880715) used as reference. Seven complete genomes of GYSVd-1 of 366-368 nucleotides (nt) in size were deposited (GenBank Acc. MW732682 to MW732688). BLASTN analysis of the sequences showed 98-100% nt identities with isolate SY-BR. Other viruses and viroids such as Grapevine fleck virus, Grapevine rupestris stem pitting-associated virus, Grapevine rupestris vein feathering virus and Hop stunt viroid were also detected. To confirm GYSVd-1 presence in Quebec vineyards, seven of the 16 HTS-positive grapevine leaf tissue samples were subjected to total RNA extraction, followed by RT-PCR assay as before (Adkar-Purushothama et al. 2015; Sahana et al. 2013); all were positive by RT-PCR. The PCR products were directly Sanger-sequenced, and they showed 100% nt identity to the HTS derived sequences. Three of the seven GYSVd-1 positive grapevines exhibited yellow leaf spots and flecks and tiny yellow leaves, but their mixed infection status makes definitive symptoms association difficult to determine. Previously, Hop stunt viroid was reported from grapevines in Canada (Xiao et al. 2019; Fall et al. 2020) but to the best of our knowledge, this is the first report of GYSVd-1 infecting grapevines in Canada, specifically in the province of Quebec. Further research is required to assess the GYSVd-1 related yield loss. Monitoring and testing for GYSVd-1 infection is necessary to prevent propagation of infected materials, spread, and potential negative impact for the Canadian grapevine industry.

High HIV-1 Virological Failure and Drug Resistance among Adult Patients Receiving First-Line ART for At least 12 Months at a Decentralized Urban HIV Clinic Setting in Senegal before the Test-and-Treat

Background:

The feasibility of antiretroviral therapy (ART) monitoring remains problematic in decentralized HIV clinic settings of sub-Saharan Africa. We assessed the rates and correlates of HIV-1 virological failure (VF) and drug resistance (DR) in 2 pre-test-and-treat urban clinic settings of Senegal.

Methods:

Consenting HIV-1-infected adults (⩾18 years) receiving first-line ART for ⩾12 months were cross-sectionally enrolled between January and March 2015, at the referral outpatient treatment center of Dakar (n = 151) and decentralized regional hospital of Saint-Louis (n = 127). In the 12 months preceding plasma specimens’ collection patients at Saint-Louis had no viral load (VL) testing. Significant predictors of VF (VL ⩾ 1000 copies/ml) and DR (clinically relevant mutations) were determined using binomial logistic regression in R software.

Results:

Of the 278 adults on EFV-/NVP-based regimens, 32 (11.5% [95%CI: 8.0-15.9]) experienced VF. Failing and non-failing patients had comparable median time [interquartile] on ART (69.5 [23.0-89.5] vs 64.0 [34.0-99.0] months; P = .46, Mann–Whitney U-test). Of the 27 viraemic isolates successfully genotyped, 20 (74.1%) carried DR mutations; most frequent were M184VI (55.6%), K103N (37.1%), thymidine analog mutations (29.6%), Y181CY (22.2%). The pattern of mutations did not always correspond to the ongoing treatment. The adjusted odds of VF was significantly associated with the decentralized clinic site (P < .001) and CD4 < 350 cells/mm³ (P < .006). Strong correlates of DR also included Saint-Louis (P < .009), CD4 < 350 cells/mm³ (P <. 001), and nevirapine-based therapies (comparator: efavirenz-based therapies; P < .027). In stratification analyses by site, higher rate of VF at Saint-Louis (20.5% [95%CI: 13.8-28.5] vs 4.0% [95%CI: 1.5-8.5] in Dakar) was associated with nevirapine-based therapies (OR = 3.34 [1.07-11.75], P = .038), self-reported missing doses (OR = 3.30 [1.13-10.24], P = .029), and medical appointments (OR = 2.91 [1.05-8.47], P = .039) in the last 1 and 12 months(s), respectively. The higher rate of DR at Saint-Louis (12.9% [95%CI: 7.6-20.1] vs 2.7% [95%CI: 0.7-6.7] in Dakar) was associated with nevirapine-based therapies (OR = 5.13 [1.12-37.35], P = .035).

Conclusion:

At decentralized urban settings, there is need for enhanced virological monitoring and adherence support. HIV programs in Senegal should intensify early HIV diagnosis for effective test-and-treat. These interventions, in addition to the superiority of efavirenz-based therapies provide a favorable framework for transitioning to the recommended potent drug dolutegravir, thereby ensuring its long-term use.

Renal impairment assessment on adults living nearby a landfill: Early kidney dysfunction biomarkers linked to the environmental exposure to heavy metals

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Health risk of the neighboring population of the Mbeubeuss landfill (Senegal).

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Assessment of the impact of Cd/Pb exposure through dysfunction renal biomarkers.

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Specific increases of a set of early dysfunction renal biomarkers in exposed subjects.

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Glomerular and tubular dysfunction in exposed subjects.

The aim of this study was to assess the integrity and kidney overall functional capacity of subjects exposed to landfill emissions. Urine and blood levels of Pb and Cd, and several of the newly biomarkers of nephrotoxicity (Kim Injury Molecule 1 (KIM-1), alpha-1 Microglobulin (α1 M), beta-2 Microglobulin (β2 M), Cystatin-C (Cyst C), Clusterin, alpha-glutathione S-transferase (GSTα), pi-glutathione S-transferase (GSTπ), Tissue Inhibitor of Metalloproteinase-1 (TIMP1), Calbindin, Neutrophil Gelatinase-Associated Lipocalin (NGAL), Osteopontin (OPN), (Retinol Binding Protein(RBP), Liver-type Fatty Acid-Binding Protein (FABP-1), Trefoil Factor 3 (TFF3), Collagen VI) were measured in order to assess glomerular and tubule damage in adults living near a landfill.

Our results indicate glomerular dysfunction in exposed subjects, and supported evidence of necrosis of proximal and distal tubule epithelial cells as specific biomarkers began to appear in the urine.

Positive correlation by Pearson test were obtained between : blood Pb and B-OPN, B-Cyst C, Calbindin, U-KIM-1, TIMP1, U-OPN, and U-Clusterin; and also, between urinary Cd and TIMP1, B-Clusterin, U-OPN, FABP-1, Albumin, and U-Clusterin. The relation between biomarkers of Cd/Pb exposure and early effect biomarkers in this study clearly predicts the future risk of severe kidney injury in subjects living close to the landfill.

[Intradetrusor injections of botulinum toxin A to treat urinary incontinence due to bladder overactivity during idiopathic Parkinson's disease]

INTRODUCTION

During idiopathic Parkinson's disease (IPD), lower urinary tract symptoms and dysfunctions are frequent, dominated by overactive bladder and detrusor overactivity (OAB, DO). Intradetrusor Injection (IDI) of Botulinum Toxin A (BTA) is recommended as second-line treatment for neurogenic urinary incontinence related to DO in multiple sclerosis or spinal cord injury patients. However, there is little data on BTA IDI to treat incontinence owing to OAB and DO during idiopathic Parkinson's disease. The objective of this study is to evaluate efficacy and tolerance of BTA IDI in patients suffering IPD.

PATIENTS AND METHODS

We conducted a retrospective study in IPD patients treated with BTA IDI from 2012 to 2018. For each patient we compared patient clinical and urodynamic data at baseline before the first injection and 8 weeks following the injection. We defined 3 levels of effects (perfect, improved, failure), corresponding to 3-dimension composite criteria: clinical, quality of life (Likert scale), urodynamics.

RESULTS

Sixteen patients were included from 2012 to 2018. The median age was 73 (70-78.25). The median number of micturition/day before and after TBA was 13 (10-16) and 9 (6.75-13.25) (p=0.022). The median number of pad used/day before and after BTA was 5.4 (2-5) and 1 (0-5) (p=0.035). Median USP scores for OAB was 15.5 (11.75-20) and 14 (6.75-15.25). Median score on the Likert scale was 1 (0-1.5) meaning "slight improvement" felt by the patient. The median maximum cystometric capacity raised from 130cm³ (41.25-187.75) to 217cm³ (165-376.75) (p=0,013). Among the patients, 20% had a perfect result, 40% were significantly improved and in 40% TBA injections failed. After TBA 4/14 patients (28%) needed intermittent self-catheterization. No severe side effect was observed.

CONCLUSION

In this retrospective study we observe some short-term efficacy of TBA IDI to treat urinary incontinence owing to OAB/DO in patients with IPD in 60% of patients. These results are consistent with findings from previous retrospective studies. Prospective data coming from larger cohorts are now tremendously needed to clarify the best patient responders profiles, the actual TBA dose, and eventually to define TBA IDI place in the therapeutic algorithm of IPD patients' incontinence.

LEVEL OF EVIDENCE

4.

Curing temperature dependency of the release of arsenic from cemented paste backfill made with Portland cement

In this research, the effect of curing temperature on the metalloid (As) leachability of cemented paste backfill (CPB; a mix of tailings, cement and water) is studied. ASTM C 1308 leaching protocol is used to determine the leachability of CPB samples subjected to different curing temperatures (2, 20 and 35 °C). In addition, the effect of curing temperature on the microstructure of CPB is assessed to determine if the temperature dependence of the leaching characteristics of CPB is related to variations in the microstructure of the cement matrix. The microstructural techniques used include, powder x-ray diffraction, mercury intrusion porosimetry, and scanning electron microscopy techniques. The results obtained indicate that the curing temperature has a significant effect on the leachability of CPB. It is found that as curing temperature increased from 2 °C to 35 °C the performance of the CPB for arsenic immobilization decreased. The magnitude of this temperature-induced change in As-leachability of CPB depends on the curing temperature range (low (≤20 °C) or elevated (35 °C) temperatures). This curing temperature dependency of the leachability of CPB is attributable to the temperature-induced changes in the pore structure of CPB, formation/development of hydration products and pH in the CPBs during the curing process. The results also indicate that diffusion dominates as the leaching mechanism through the studied temperature range and is independent of curing temperature. However, curing temperature does control the availability for arsenic to leach. The new findings presented in this paper will contribute to design more environmental-friendly cemented paste backfill materials and structures, which is vital for sustainable mining.

Individual exposure level following indoor and outdoor air pollution exposure in Dakar (Senegal)

The consequences of indoor and outdoor air pollution on human health are of great concern nowadays. In this study, we firstly evaluated indoor and outdoor air pollution levels (CO, CO₂, NO, NO₂, PM₁₀) at an urban site in Dakar city center and at a rural site. Then, the individual exposure levels to selected pollutants and the variations in the levels of biomarkers of exposure were investigated in different groups of persons (bus drivers, traders working along the main roads and housemaids). Benzene exposure levels were higher for housemaids than for bus drivers and traders. High indoor exposure to benzene is probably due to cooking habits (cooking with charcoal), local practices (burning of incense), the use of cleaning products or solvent products which are important emitters of this compound. These results are confirmed by the values of S-PMA, which were higher in housemaids group compared to the others. Urinary 1-HOP levels were significantly higher for urban site housemaids compared to semirural district ones. Moreover, urinary levels of DNA oxidative stress damage (8-OHdG) and inflammatory (interleukin-6 and -8) biomarkers were higher in urban subjects in comparison to rural ones. The air quality measurement campaign showed that the bus interior was more polluted with PM₁₀, CO, CO₂ and NO than the market and urban or rural households. However, the interior of households showed higher concentration of VOCs than outdoor sites confirming previous observations of higher indoor individual exposure level to specific classes of pollutants.

Physico-chemical characterization and in vitro inflammatory and oxidative potency of atmospheric particles collected in Dakar city's (Senegal)

Exposure to atmospheric pollutants has been recognized as a major risk factor of respiratory and cardiovascular diseases. Fine particles (PM_2.5) and a coarser fraction (PM_>2.5) sampled at an urban site in Dakar (HLM), characterized by high road traffic emissions, were compared with particles sampled at a rural area, Toubab Dialaw located about 40 km from Dakar. The physicochemical characteristics of samples revealed that PMs differ for their physical (surface area) and chemical properties (in terms of CHN, metals, ions, paraffins, VOCs and PAHs) that were 65-75% higher in urban samples. Moreover the fine PMs contain higher amounts of anthropogenic related pollutants than the PM_>2.5 one. These differences are sustained by the ratios reported for the analysed PAHs which suggest as predominant primary emission sources vehicle exhausts at urban site and biomass combustion at the rural site. The inflammatory response and the oxidative damages were evaluated in BEAS-2B cells by the quantification of 4 selected inflammatory cytokines (TNF-α, IL-1β, IL-6, IL-8) and of total carbonylated proteins and the oxidative DNA adduct 8-OHdG after 8 or 24 h exposure. In accordance with the different sources and different physical and chemical properties, the inflammatory response and the oxidative damages were found higher in bronchial cells exposed to urban PMs. These data confirm the importance, also for West African countries, to evaluate the correlation between PM physico-chemical properties and potential biological impacts.

[Neuro-Behçet in a Sub-Saharan Africa Country: a Series of Sixteen Patients in Fann Teaching Hospital, Dakar, Senegal]

Neuro-Behçet (NB) African studies are mainly North African, but Sub-Saharan Africa is not to be outdone. Our aim was to describe diagnostic and therapeutic features of NB in a Senegalese series collected in Dakar. This was a descriptive and retrospective study conducted at the Neurology department of Fann Teaching Hospital in Dakar, Senegal. All patients who met the NB's diagnostic criteria were included. Sixteen patients were collected, 14 males and 2 females with an average age of 40 years [18-71]. The main neurological signs were motor deficit (13 cases), headache (10 cases), and language disorders (4 cases). Extra-neurological signs were dermatological (14 cases), ocular (2 cases), and articular (2 cases) with aseptic unilateral gonarthritis. Fever was present in 9 patients. Neurological involvement was mostly isolated parenchymal (8 cases) or mixed (6 cases). The main clinical forms of NB were rhombencephalitis (8 cases) and retrobulbar optic neuritis (4 cases). Seven patients had a cerebral angio-Behçet with cerebral venous thrombosis (3 cases), ischemic stroke (2 cases), and intracerebral hematoma (2 cases). Under prednisone (16 cases) and azathioprine (3 cases), the short-term clinical outcome was mostly favorable (14 cases) with a modified Rankin scale at 2. NB is an under-diagnosed adult male disease in Sub-Saharan Africa and further studies are needed.

Surveillance of transmitted HIV-1 antiretroviral drug resistance in the context of decentralized HIV care in Senegal and the Ebola outbreak in Guinea

Objectives

Disruption in HIV care provision may enhance the development and spread of drug resistance due to inadequate antiretroviral therapy. This study thus determined the prevalence of HIV-1 transmitted drug resistance (TDR) in settings of decentralized therapy and care in Senegal and, the Ebola outbreak in Guinea. Antiretroviral-naïve patients were enrolled following a modified WHO TDR Threshold Survey method, implemented in Senegal (January–March 2015) and Guinea (August–September 2015). Plasma and dried blood spots specimens, respectively from Senegalese (n = 69) and Guinean (n = 50) patients, were collected for direct sequencing of HIV-1 pol genes. The Stanford Calibrated Population Resistance program v6.0 was used for Surveillance Drug Resistance Mutations (SDRMs).

Results

Genotyping was successful from 54/69 (78.2%) and 31/50 (62.0%) isolates. In Senegal, TDR prevalence was 0% (mean duration since HIV diagnosis 4.08 ± 3.53 years). In Guinea, two patients exhibited SDRMs M184V (NRTI), T215F (TAM) and, G190A (NNRTI), respectively. TDR prevalence at this second site, however, could not be ascertained because of low sample size. Phylogenetic inference confirmed CRF02_AG predominance in Senegal (62.96%) and Guinea (77.42%). TDR prevalence in Senegal remains extremely low suggesting improved control measures. Continuous surveillance in both settings is mandatory and, should be done closest to diagnosis/transmission time and with larger sample size.

Prevention of isoniazid toxicity by NAT2 genotyping in Senegalese tuberculosis patients

Isoniazid (INH), recommended by WHO (World Health Organization) in the treatment of tuberculosis (TB), is metabolized primarily by the genetically polymorphic N-acetyltransferase 2 (NAT2) enzyme. The human population is divided into three different phenotypic groups according to acetylation rate: slow, intermediate, and fast acetylators. The objective of this study was to explore the relationship between NAT2 genotypes and the serum concentrations of INH. Blood samples from 96 patients with TB were taken for the analysis. NAT2 polymorphisms on coding region were examined by polymerase chain reaction (PCR) direct sequencing; the acetylation status was obtained by measuring isoniazid (INH) and its metabolite, acetylisoniazid (AcINH) in plasma was obtained by using the liquid chromatography coupled to mass spectrometry. TB patients were distributed into two groups of fast and slow acetylators according to the acetylation index calculated based on the plasma concentration of INH in the 3rd hour (T3) after an oral dose. Our PCR analysis identified several alleles, where NAT2*4, NAT2*5A, NAT2*6A, and NAT2*13A were the most important. The concentrations of INH varied between 1.10 mg/L and 13.10 mg/L at the 3rd hour and between 0.1 and 9.5 mg/L at the 6th hour. The use of the acetylating index I₃ allowed the classification of tested patients into two phenotypic groups: slow acetylators (44.3% of TB patients), and rapid acetylators (55.7%). Patient’s acetylation profile provides valuable information on their therapeutic, pharmacological, and toxicological responses.

Environmental lead exposure and its relationship to traffic density among Senegalese children: a pilot study

In Senegal, as in many developing countries, traffic density is increasing in urban areas; in Dakar more than 50% of vehicles use gasoline. Yet the extent and real magnitude of the problem has neither been recognized nor assessed in these countries. Systemic data assessment of lead pollution and people's exposure are not well known in Senegal. This study was also designed to determine the impregnation levels of the lead released by the exhaust of cars and the changes of some early biological markers in Senegalese children. Blood lead (BPb) levels showed that all the children enrolled were exposed. However, lead exposure levels (from 34.7 to 145.8 mg/L) were less important for children living in rural areas (60.99-18.3 mg/L) than for those living in urban areas (106.79-16.9 mg/L). These changes could be correlated to the difference in the automobile traffic between both these regions (P B-0.001). BPb mean levels found in boys were higher than those in girls (P B-0.05). Despite elevated BPb levels, all values for blood zinc protoporphyrin and urine delta-aminolevulinic acid were within physiological ranges. In addition, variations in some biological markers of oxidative stress and renal disorders were seen; however, they must be confirmed by a future epidemiological study.

Environmental lead exposure and its relationship to traffic density among Senegalese children: a cross-sectional study

Leaded-gasoline is probably the primary source of lead (Pb) exposure in Dakar (Senegal). The present cross sectional study was undertaken to investigate the levels of Pb in Senegalese children and to present helpful data on the relationship between Pb levels and changes in biological markers of heme biosynthesis and oxidative stress. A total of 330 children, living since birth either in rural or urban areas (ie, Khombole (n=162) and Dakar (n=168), respectively) were included. During this cross sectional study, the mean blood (B)-Pb level in all children was 7.32±5.33 ųg/dL, and was influenced by the area of residence and gender. In rural children, 27 subjects (16.7%), 18 boys (19.6%) and nine girls (12.9%), had a B-Pb level >10 ųg Pb/dL, whereas 99 urban children (58.9%), respectively, 66 boys (71.8%) and 33 girls (43.4%), had alarmingly high B-Pb levels. Accordingly, urine delta-aminolevulinic acid levels were higher in children living in the urban area than in the rural areas (P B±0.001), and closely correlated with the B-Pb levels (P B±0.01). Moreover, glutathione peroxidase (GPx) activity, selenium (Se) level, glutathione reductase (GR) activity, and glutathione status were significantly influenced by area of residence and/or by gender. GPx activity and Se level were not only negatively correlated with B-Pb levels, but also positively correlated together (P B±0.01). Taken together, the present results allow us to conclude that urban children have higher B-Pb levels than rural children, and that of these children, boys have higher B-Pb levels than girls, leading thereby to alterations of heme biosynthesis and pro-oxidant/antioxidant balance. We also suggest that exposure to Pb and the Pb-induced adverse effects merits attention and that the development of preventive actions are of increasing importance in Senegal.

Foraging range of arthropods with veterinary interest: New insights for Afrotropical Culicoides biting midges (Diptera: Ceratopogonidae) using the ring method

The identification of blood meal source of arthropod vector species contributes to the understanding of host-vector-pathogen interactions. The aim of the current work was to identify blood meal source in Culicoides biting midge species, biological vectors of internationally important arboviruses of livestock and equids, using a new ecological approach. We examined the correlation between blood meal source identified in engorged Culicoides females collected in a suction light trap and the available vertebrate hosts along four rings (200, 500, 1000 and 2000 m) centered at the trap site and described the foraging range of the three main vector species of veterinary interest present in the study area, Culicoides imicola, Culicoides kingi and Culicoides oxystoma. The study was performed in four sites localized in the Niayes region of Senegal (West Africa) where recent outbreaks of African horse sickness occurred. Blood meal source identification was carried out by species-specific multiplex PCRs with genomic DNA extracted from the abdomen of engorged females collected during nine night collections for twenty-six collections. The four most abundant hosts present in the studied area (horse, cattle, goat and sheep) were surveyed in each ring zone. The blood meal source varied according to Culicoides species and host availability in each site. C. oxystoma and C. imicola females mainly fed on horses readily available at 200 m maximum from the trap location whereas females of C. kingi fed mainly on cattle, at variable distances from the traps (200 to 2000 m). C. oxystoma may also feed on other vertebrates. We discuss the results in relation with the transmission of Culicoides-borne arboviruses and the species dispersion capacities.

[Tooth decay: epidemiological and therapeutic aspects in dental service of University Teaching Hospital Yalgado Ouedraogo and Municipal Centre of Oral Health]

INTRODUCTION

In order to improve the prevention and treatment of dental caries in Burkina Faso, we conducted a study on the epidemiological and therapeutic aspects of dental caries in the dental services of University Teaching Hospital Yalgado Ouedraogo and in the Municipal Centre of Oral Health of Ouagadougou.

MATERIAL AND METHODS

A prospective and descriptive study from October, 15th 2012 to January, 15th 2013 was conducted on a sample of 191 patients. The variables recorded were: patient's identity, age, sex, area of residence, food mode, socioeconomic level, reason for consultation, oral hygiene, DMFT index, degree of tissue damage, the topography of the carious lesions and the applied therapy.

RESULTS

Caries prevalence was 93.19% more female consultations, with sex ratio at 0.77. The average age was 31 years for a sample often engaged in trade and the informal sector. Carious lesions were usually limited to less than 4 teeth. The main motivation for the consultation was pain at 82.20%.

CONCLUSION

The use of preventive care is quite low in our population. Extractions still occupy an important part of treatment. We need to improve oral hygiene and show to patients the necessity of routine visits to the dentist every year for early treatment.

Effects of environmental cadmium and lead exposure on adults neighboring a discharge: Evidences of adverse health effects

The purpose of the study was to determine Pb and Cd concentrations in humans and to assess the effect of co-exposure to these metals on biomarkers of oxidative stress and nephrotoxicity. Blood and urine levels of Pb and Cd, oxidative stress and urinary renal biomarkers were measured in 77 subjects neighboring a discharge and 52 in the control site. Exposed subjects showed significantly higher levels of lead and cadmium in blood and urine than the controls. Excessive production of reactive oxygen species induced by these metals in exposed subjects conducted to a decrease in antioxidant defense system (GPx, Selenium, GSH) and an increase in lipid peroxidation (MDA). Moreover, changes in markers of nephrotoxicity (high urinary concentrations of total protein, RBP and CC16, as well as GSTα and LDH increased activities) suggested the occurrence of discrete and early signs of impaired renal function for the discharge neighboring population.

[Urological emergencies in paediatric surgery: a survey of 40 cases]

AIMS

The objective of this study is to report our experience on the epidemiology of urological emergencies in pediatric surgery, and to analyze the diagnosis and therapeutic process.

MATERIALS AND METHODS

It was a prospective survey which was carried out between January 2010 and June 2011 in the pediatric service of Aristide Le Dantec Hospital (HALD). All the children who came for a urological emergency consultation were included in the study.

THE RESULTS

the urological emergencies accounted for forty cases which represented 2.57% of pediatric surgery emergencies. The average age of our patients was 4.5 years with extremes of 10 days and 15 years of age. 29 cases of severe big bursae were observed and among them there were strangulated hernia and ten cases of suspicious spermatic cord torsion. The other admission motives consisted of three cases of urine retention, two pyelonephritis cases, two cases of post circumcision glans sections, two paraphimosis cases, one tight phimosis case, one case of penis traumatism provoked by a game incident. The scrotum ultrasound performed on six patients helped find out a specificity of 66.6%. 60% of strangulated hernia have been reduced through under sedation taxis. In case of confirmed torsion, a detorsion followed by an orchidopexy were performed. Two orchidectomy were performed for a testicular necrosis.

CONCLUSION

the painful big bursa is the number one cause for a urology pediatric consultation. It implies a fast and adequate diagnosis and treatment so as not to miss a digestive or testicular pain.

Assessment of contamination, distribution and chemical speciation of trace metals in water column in the Dakar coast and the Saint Louis estuary from Senegal, West Africa

The water column from Dakar coast and Saint Louis estuary in Senegal, West Africa, was sampled in order to measure the contamination level by trace metals. The speciation of metals in water allowed performing a distribution between dissolved and particulate trace metals. For the dissolved metals, the metallic concentration and repartition between the organic fraction and the inorganic fraction were performed. The results show that the pollution of the estuary was more serious than in Dakar coast for Co, Cr, Ni, Pb and Zn; while, Cd and Cu were higher in Dakar coast. A strong affinity between metals and suspended particles has been revealed. Dissolved metals that have a tendency to form organic metal complexes are in decreasing order: Cd, Zn, Pb, Co=Cr=Mn, Cu and Ni. The results showed that the mobility of trace metals in estuary is controlled by dissolved organic carbon, while in coast it depends on chlorides.