Objectives: Sickle cell disease (SCD) encompasses health complications, primarily affecting the hematologic system and leading to high death rates in childhood. As a rule, the World Health Organisation (WHO) stepwise gold-standard about the strategies for prevention, diagnosis, and treatment of SCD must be multidimensional. This overview aimed to highlight current advances and challenges linked to strategic issues, diagnosis, the prevalence, and treatment of pediatric cases in Sub-Saharan Africa, particularly the Democratic Republic of the Congo. Methods: We searched data on Google Scholar, Medline, PubMed, Science Direct, Scopus, and ResearchGate. Results: The laboratory diagnosis of SCD has progressed from conventional electrophoresis to rapid point-of-care tests that allows early neonate screening. HemoTypeSCTM is an affordable test for neonatal screening in DRC. The pediatric SCD prevalence in Sub-Saharan Africa lay within 1–7.7% of homozygous(SS) and 15–40% of the heterozygous(AS) forms of SCD, depending on the method used and the ethnic population tested. Various supportive management protocols for comorbidities and complications exist, but they are not standardized in the Region. Conclusion: Notwithstanding some progress accomplished, the disease is still challenging in Sub-Saharan Africa due to limited early diagnostic testing and a lack of specific medications. There is a need for harmonizing therapeutic protocols and conducting controlled valid clinical trials. © 2022 The Author(s). Published by Informa UK Limited, trading as Taylor & Francis Group.
Background The accuracy and reliability of rapid diagnostic tests are critical for monitoring and diagnosing SARS-CoV-2 infection in the general population. This study aimed to evaluate the analytical performance of the BIOSYNEX COVID-19 Ag BSS (Biosynex Swiss SA, Fribourg, Switzerland) antigen rapid diagnostic test (BIOSYNEX Ag-RDT), which targets the SARS-CoV-2 N-nucleocapsid protein for the diagnosis of COVID-19. The Ag-RDT was compared with a real-time RT-PCR (rtRT-PCR) as gold standard for performance measurement. Methods Two nasopharyngeal flocked swabs were prospectively collected simultaneously in March and April 2021 from 967 individuals aged ≥ 18 years tested for SARS-CoV-2 in two private laboratories, Paris, France. Results Overall, the Ag-RDT demonstrated high sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of 81.8%, 99.6%, 96.6%, and 97.5%, respectively. The agreement (97.0%), reliability assessed using Cohen’s κ-coefficient (0.87), and accuracy evaluated using Youden index (J) (81.6%) in detecting SARS-CoV-2 were high. The analytical performance of the Ag-RDT remained high when there was significant viral shedding (i.e., N gene Ct values ≤ 33 on reference RT-PCR). The sensitivity was only 55.2% in case of low or very low viral excretion (Ct > 33). Conclusions The BIOSYNEX Ag-RDT is a promising, potentially simple diagnostic tool, especially in symptomatic COVID-19 patients with substantial viral excretion in the nasopharynx.
Metallic nanoparticles (MNPs) produced by green synthesis using plant extracts have attracted huge interest in the scientific community due to their excellent antibacterial, antifungal and antibiofilm activities. To evaluate these pharmacological properties, several methods or protocols have been successfully developed and implemented. Although these protocols were mostly inspired by the guidelines from national and international regulatory bodies, they suffer from a glaring absence of standardization of the experimental conditions. This situation leads to a lack of reproducibility and comparability of data from different study settings. To minimize these problems, guidelines for the antimicrobial and antibiofilm evaluation of MNPs should be developed by specialists in the field. Being aware of the immensity of the workload and the efforts required to achieve this, we set out to undertake a meticulous literature review of different experimental protocols and laboratory conditions used for the antimicrobial and antibiofilm evaluation of MNPs that could be used as a basis for future guidelines. This review also brings together all the discrepancies resulting from the different experimental designs and emphasizes their impact on the biological activities as well as their interpretation. Finally, the paper proposes a general overview that requires extensive experimental investigations to set the stage for the future development of effective antimicrobial MNPs using green synthesis.
Background Across the tropics, the share of secondary versus primary forests is strongly increasing. The high rate of biomass accumulation during this secondary succession relies on the availability of essential nutrients, such as nitrogen (N). Nitrogen primarily limits many young secondary forests in the tropics. However, recent studies have shown that forests of the Congo basin are subject to high inputs of atmospheric N deposition, potentially alleviating this N limitation in early succession. Methods To address this hypothesis, we assessed the N status along a successional gradient of secondary forests in the Congo basin. In a set-up of 18 plots implemented along six successional stages, we quantified year-round N deposition, N leaching, N2O emission and the N flux of litterfall and fine root assimilation. Additionally, we determined the N content and C:N stoichiometry for canopy leaves, fine roots, and litter, as well as δ¹⁵N of canopy leaves. Results We confirmed that these forests receive high amounts of atmospheric N deposition, with an increasing deposition as forest succession proceeds. Additionally, we noted lower C:N ratios, and higher N leaching losses, N2O emission, and foliar δ¹⁵N in older secondary forest (60 years). In contrast, higher foliar, litter and root C:N ratios, and lower foliar δ¹⁵N, N leaching, and N2O emission in young (< 20 years) secondary forest were observed. Conclusions Altogether, we show that despite high N deposition, this early forest succession still shows conservative N cycling characteristics, which are likely indicating N limitation early on in secondary forest succession. As secondary succession advances, the N cycle gradually becomes more open.
The assessment of population vulnerability under climate change is crucial for planning conservation as well as for ensuring food security. Coffea canephora is, in its native habitat, an understorey tree that is mainly distributed in the lowland rainforests of tropical Africa. Also known as Robusta, its commercial value constitutes a significant revenue for many human populations in tropical countries. Comparing ecological and genomic vulnerabilities within the species’ native range can provide valuable insights about habitat loss and the species’ adaptive potential, allowing to identify genotypes that may act as a resource for varietal improvement. By applying species distribution models, we assessed ecological vulnerability as the decrease in climatic suitability under future climatic conditions from 492 occurrences. We then quantified genomic vulnerability (or risk of maladaptation) as the allelic composition change required to keep pace with predicted climate change. Genomic vulnerability was estimated from genomic environmental correlations throughout the native range. Suitable habitat was predicted to diminish to half its size by 2050, with populations near coastlines and around the Congo River being the most vulnerable. Whole‐genome sequencing revealed 165 candidate SNPs associated with climatic adaptation in C. canephora, which were located in genes involved in plant response to biotic and abiotic stressors. Genomic vulnerability was higher for populations in West Africa and in the region at the border between DRC and Uganda. Despite an overall low correlation between genomic and ecological vulnerability at broad scale, these two components of vulnerability overlap spatially in ways that may become damaging. Genomic vulnerability was estimated to be 23% higher in populations where habitat will be lost in 2050 compared to regions where habitat will remain suitable. These results highlight how ecological and genomic vulnerabilities are relevant when planning on how to cope with climate change regarding an economically important species. We characterized the ecological and genomic vulnerability of the wild Robusta coffee (Coffea canephora). Using species distribution modelling, we predicted a loss of ~50% in suitable habitat area in 2050. We detected 165 genetic markers that could be involved in facilitating adaptation to future climate conditions. Yet, we estimated that genomic vulnerability was higher for populations at the West and East margins of the current distribution and ~23% higher in populations where habitat will be lost in 2050. Our study highlights how ecological and genomic vulnerabilities are relevant for conservation policies and when planning for varietal improvement.
Yams (Dioscorea spp.) possess the potential to contribute to food security and poverty al-leviation in DR Congo; however, yam production is limited by several constraints, including the lack of yam improvement programs to address challenges relating to yield improvement, resistance to foliar diseases, and post-harvest tuber quality. Identification of a superior genotype for these traits and reservoirs of genes for improvement would guide yams' improvement. This study aims to evaluate and identify landraces with superior performance for farmers and consumers. We evaluated 191 accessions from six yam species, and significant variation in the performances was observed at p < 0.05. Accessions of D. alata were superior for tuber oxidative browning (−0.01), D. cay-enensis for high yield potential (29 t/ha), D. bulbifera for yam mosaic virus (YMV) tolerance (AUDPC = 3.88), and D. rotundata for tuber dry matter content (37%). A high genotypic and phenotypic coefficient of variation (>40) was observed for tuber yield, number of tubers per plots, tuber flesh oxi-dative browning, and tuber flesh texture. High broad-sense heritability estimates (>60) were similarly observed for all the assessed parameters except number of tubers per plot. Tuber size was identified as the best predictor for tuber yield (b = 2.64, p < 0.001) and tuber dry matter content (b = 2.21, p < 0.001). The study identified twenty stable landrace accessions from three Dioscorea species (D. alata (7); D. cayenensis (2); D. rotundata (11)). These accessions combined high yield potential, high tuber dry matter, high tolerance to YMV and YAD, and low tuber flesh oxidation. The accessions could be considered for the establishment of a yam improvement program in DR Congo.
Objective: To determine the prevalence of gestational diabetes and associated risk factors in the eastern region of the Democratic Republic of Congo (DRC). Methods: A cross-sectional study was conducted in Goma city, Idjwi, Ngungu and Rutshuru districts between April 2019 and February 2021. Were included, pregnant women between 24 to 28 weeks of amenorrhea who consented to participate in the study. Blood sugar, anthropometric parameters and obstetrical and family history were studied. Gestational diabetes was defined as blood glucose level between 92 and 125mg/dL. Results: The overall prevalence was 21.2% (n=391) and was higher in Rutshuru [27.2% (n=92)] and Goma [26.9% (n=134)] compared to Ngungu [10.0% (n=110)] (p=0.005). An increased risk was associated with a history of a newborn weighing ≥ 4000g [OR 2.4 95% CI (1.3 – 4.4)] or family diabetes [OR 2.9 95% CI (2.0 – 4.9)]. Median age in the pathological group was not different from that with normal blood glucose [25.0 (16.0 – 44.0) Vs 26.0 (16.0 – 44.0)] (p = 0.67). The prevalence tended to increase for pregnant women with a mid-upper arm circumference ≥ 280 mm [28.1% (n = 57)] Vs [19.3% (n=322)] if < 280 mm, [OR (95% CI)] [1.5 (0.9 - 2.3)] (p = 0.13). Conclusion: Gestattional diabetes was found in one out of five pregnant women regardless their age. The history of macrosomia birth and diabetes in the family were the main risk factors.
The assessment of water quality in Bukavu urban rivers (Kahuwa (KW), Wesha (WS), Tshula (TL), Bwindi (BN), and Nyamuhinga (NG)) was conducted twice a month from 2017 to 2019 at low and high frequencies following standard sampling techniques. Results showed that water temperature (WT), dissolved oxygen (DO), and electrical conductivity (EC) were within WHO standards for surface waters, except pH for some stations on KW and NG rivers, where it was highly alkaline. However, PO4³⁻, NH4⁺, NO2⁻ and NO3⁻ concentrations increased gradually from upstream to downstream and were very high compared to the WHO standards, which means the river waters were heavily polluted. The highest nutrients concentrations were recorded in the dry season for all rivers, except KW and NG rivers at the midstream and downstream stations. The nutrient average fluxes collected at low-frequency (FLF) and high-frequency (FHF) downstream of each river were 95% correlated. Flux variations regarding PO4³⁻, NH4⁺, NO2⁻ and NO3⁻ were significant for all rivers except PO4³⁻ in the NG river. The number of nutrients exported to Lake Kivu was estimated to average 0.6 t km⁻² of PO4³⁻, 2.4 t km⁻² of NH4⁺, 1.0 t km⁻² of NO2⁻ and 41.0 t km⁻² of NO3⁻ per year. Given the current deterioration status of water quality in Bukavu urban rivers, there is an urgent need to improve liquid and solid waste management strategy in the area, to set up efficient wastewater treatment plants and sewage systems in various catchments to mitigate cumulative pollution of the rivers and the lake.
1. Organisms of all species must balance their allocation to growth, survival and recruitment. Among tree species, evolution has resulted in different life‐history strategies for partitioning resources to these key demographic processes. Life‐history strategies in tropical forests have often been shown to align along a trade‐off between fast growth and high survival, i.e. the well‐known fast‐slow continuum. In addition, an orthogonal trade‐off has been proposed between tall stature – resulting from fast growth and high survival – and recruitment success, i.e. a stature−recruitment trade‐off. However, it is not clear if these two independent dimensions of life‐history variation structure tropical forests worldwide. 2. We used data from 13 large‐scale and long‐term tropical forest monitoring plots in three continents to explore the principal trade‐offs in annual growth, survival and recruitment as well as tree stature. These forests included relatively undisturbed forests as well as typhoon‐disturbed forests. Life‐history variation in twelve forests was structured by two orthogonal trade‐offs, the growth−survival trade‐off and the stature−recruitment trade‐off. Pairwise Procrustes analysis revealed a high similarity of demographic relationships among forests. The small deviations were related to differences between African and Asian plots. 3. Synthesis. The fast‐slow continuum and tree stature are two independent dimensions structuring many, but not all tropical tree communities. Our discovery of the consistency of demographic trade‐offs and life‐history strategies across different forest types from three continents substantially improves our ability to predict tropical forest dynamics worldwide.
Acute kidney injury (AKI) is a complex condition that can occur in both community and hospital settings and has many aetiologies. These aetiologies may be infectious, toxic, surgical, or related to the different management methods. Although it is a major public health problem worldwide, it must be emphasised that both its incidence and mortality rate appear to be very high in sub-Saharan African (SSA) countries compared to developed countries. The profile of AKI is very different from that of more developed countries. There are no reliable statistics on the incidence of AKI in SSA. Infections (malaria, HIV, diarrhoeal, and other diseases), nephrotoxins, and obstetric and surgical complications are the main aetiologies in Africa. The management of AKI is costly and associated with high rates of prolonged hospitalisation and in-hospital mortality.
Tree size shapes forest carbon dynamics and determines how trees interact with their environment, including a changing climate. Here, we conduct the first global analysis of among‐site differences in how aboveground biomass stocks and fluxes are distributed with tree size. We analyzed repeat tree censuses from 25 large‐scale (4–52 ha) forest plots spanning a broad climatic range over five continents to characterize how aboveground biomass, woody productivity, and woody mortality vary with tree diameter. We examined how the median, dispersion, and skewness of these size‐related distributions vary with mean annual temperature and precipitation. In warmer forests, aboveground biomass, woody productivity, and woody mortality were more broadly distributed with respect to tree size. In warmer and wetter forests, aboveground biomass and woody productivity were more right skewed, with a long tail towards large trees. Small trees (1–10 cm diameter) contributed more to productivity and mortality than to biomass, highlighting the importance of including these trees in analyses of forest dynamics. Our findings provide an improved characterization of climate‐driven forest differences in the size structure of aboveground biomass and dynamics of that biomass, as well as refined benchmarks for capturing climate influences in vegetation demographic models.
Yam ( Dioscorea spp.) is cultivated in many villages of DR Congo as a means to sustain food security and alleviate poverty. However, the extent of the existing diversity has not been studied in details thus, considered as an orphan. A survey covering 540 farmers in 54 villages was conducted in six major yam growing territories covering three provinces in DR Congo to investigate the diversity, management and utilization of yam landraces using pre-elaborate questionnaires. Subject to synonymy, a total of 67 landraces from five different species were recorded. Farmers’ challenges limiting yam production were poor tuber qualities (69%), harvest pest attack (7%), difficulty in harvesting (6%), poor soil status (6%). The overall diversity was moderate among the recorded yam germplasm maintained at the household level (1.32) and variability exist in diversity amongst the territories and provinces. Farmers’ in territories of Tshopo and Mongala provinces maintained higher level of germplasm diversity (2.79 and 2.77) compared to the farmers in territories of Bas-Uélé (1.67). Some yam landraces had limited abundance and distribution due to loss of production interest in many villages attributable to poisons contained hence, resulting in possible extinction. Farmers’ most preferred seed source for cultivation were backyard (43%) and exchange with neighboring farmers (31%) with the objective of meeting food security and generating income. In villages where yam production is expanding, farmers are relying on landraces with good tuber qualities and high yield even though they are late maturing. This study revealed the knowledge of yam landrace diversity, constraints to production and farmers’ preferences criteria as a guide for collection and conservation of yam germplasm for yam improvement intervention.
We elucidate the value orientations (VOs) towards wild meat/wildlife in the Tshopo Province of the Democratic Republic of Congo, distinguishing between the provincial capital and rural areas. Based on stories prompted by four primary emotions, the most frequently encountered VOs were: concern for safety, nutrition and taste, and caring/respect. Rural people were more likely to express anthropocentric VOs. However, their stories did not necessarily associate negatively with caring/respect, suggesting that wildlife users may also be sensitive to biocentric values. Age, gender, and wealth were good predictors for biocentric VOs, with young women from the city more likely to express biocentric values. VOs and emotions related differently to specific wildlife species. Mutualism was not frequently elucidated in the stories. The associations we found provide crucial information to understand differences in value orientations across groups, identify barriers to change, and tailor behavior change campaigns to the local context.
The growth and survival of individual trees determine the physical structure of a forest with important consequences for forest function. However, given the diversity of tree species and forest biomes, quantifying the multitude of demographic strategies within and across forests and the way that they translate into forest structure and function remains a significant challenge. Here, we quantify the demographic rates of 1,961 tree species from temperate and tropical forests and evaluate how demographic diversity (DD) and demographic composition (DC) differ across forests, and how these differences in demography relate to species richness, aboveground biomass, and carbon residence time. We find wide variation in DD and DC across forest plots, patterns that are not explained by species richness or climate variables alone. There is no evidence that DD has an effect on either aboveground biomass or carbon residence time. Rather, the DC of forests, specifically the relative abundance of large statured species, predicted both biomass and carbon residence time. Our results demonstrate the distinct demographic compositions of globally distributed forests, reflecting biogeography, recent history, and current plot conditions. Linking the demographic composition of forests to resilience or vulnerability to climate change, will improve the precision and accuracy of predictions of future forest composition, structure and function.
Globally, tropical forests are assumed to be an important source of atmospheric nitrous oxide (N 2 O) and sink for methane (CH 4). Yet, although the Congo Basin comprises the second largest tropical forest and is considered the most pristine large basin left on Earth, in situ N 2 O and CH 4 flux measurements are scarce. Here, we provide multi-year data derived from on-ground soil flux (n = 1558) and riverine dissolved gas concentration (n = 332) measurements spanning montane, swamp, and lowland forests. Each forest type core monitoring site was sampled at least for one hydrological year between 2016-2020 at a frequency of 7-14 days. We estimate a terrestrial CH 4 uptake (in kg CH 4-C ha −1 yr −1) for montane (−4.28) and lowland forests (−3.52) and a massive CH 4 release from swamp forests (non-inundated 2.68; inundated 341). All investigated forest types were a N 2 O source (except for inundated swamp forest) with 0.93, 1.56, 3.5, and −0.19 kg N 2 ON ha −1 yr −1 for montane, lowland, non-inundated swamp, and inundated swamp forests, respectively.
Objective The contribution of African authors to the biomedical literature is small. We evaluated the African and non-African scientific production published in the international literature on the COVID-19 in Africa during the first year of the epidemic (2020). Methods Papers on COVID-19 in Africa were extracted from the Medline (Pubmed) database for bibliometric analysis including the proportions of three leading and last authors by study type, study country, authors’ and laboratories/institutions’ countries of affiliation, and journal ranking. Results A total of 160 articles fulfilling the inclusion criteria was analyzed. The majority (91.3%) was produced by half (53.7%) of African countries, with important regional disparities, and generally without sources of funding mentioned. The majority (>85.0) of authors in lead positions (first, second, third, and last authors) were Africans. Only a small number (8.7%) of studies on COVID-19 in Africa were carried out by laboratories not on the African continent (mainly Europe, USA and China) and generally received funding. The last and first authors were more frequently of non-African origin in journals with an Impact Factor ranking ≥1, and more frequently of African origin in journals with a lower ranking (< 1). The first and last non-African authors tended to report their studies in high-ranking ≥1 journals. Conclusions Our study demonstrates the emergence of promising African research capable of publishing in indexed but low-impact factor medical journals and reveals the persistence of a North-South asymmetry in international cooperation in biomedical research with Africa.
Although patients infected with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), influenza A, influenza B and respiratory syncytial virus (RSV) show comparable or very similar manifestations, the therapeutic approaches of these respiratory viral infections are different, which requires an accurate diagnosis. Recently, the novel multiplex real-time reverse transcription-polymerase chain reaction assay AMPLIQUICK ® Respiratory Triplex (BioSynex SA, Illkirch-Graffenstaden, France) allows simultaneous detection and differentiation of SARS-CoV-2, influenza A, influenza B, and RSV in respiratory tract samples. We herein evaluated the performance of the AMPLIQUICK ® Respiratory Triplex for the detection of the four viruses in respiratory specimens, using Allplex™ Respiratory Panel 1 and 2019-nCoV assays (Seegene, Seoul, Korea) as reference comparator assays. A total of 359 archived predetermined respiratory samples, including 83, 145, 19 and 95 positive specimens for SARS-CoV-2, influenza A, influenza B and RSV respectively, were included. The AMPLIQUICK ® Respiratory Triplex showed high concordance with the reference assays, with an overall agreement for SARS-CoV-2, influenza A, influenza B, and RSV at 97.6%, 98.8%, 98.3% and 100.0%, respectively, and high κ values ranging from 0.93 to 1.00, indicating an almost perfect agreement between assays. Furthermore, high correlations of cycle threshold (C t ) values were observed for positive samples of the four viruses between the AMPLIQUICK ® Respiratory Triplex and comparator assays, with an overall high agreement between C t values assessed by Bland-Altman analyses. In conclusion, these observations demonstrate that the multiplex AMPLIQUICK ® Respiratory Triplex is a reliable assay for the qualitative detection and differentiation of SARS-CoV-2, influenza A, influenza B, and RSV in respiratory specimens, which may prove useful for streamlining diagnostics during the winter influenza-seasons.
Most Central African rainforests are characterized by a remarkable abundance of light-demanding canopy species: long-lived pioneers (LLP) and non-pioneer light demanders (NPLD). A popular explanation is that these forests are still recovering from intense slash-and-burn farming activities, which abruptly ended in the 19th century. This “human disturbance” hypothesis has never been tested against spatial distribution patterns of these light demanders. Here, we focus on the 28 most abundant LLP and NPLD from 250 one-ha plots distributed along eight parallel transects (~50 km) in the Yangambi forest. Four species of short-lived pioneers (SLP) and a single abundant shade-tolerant species (Gilbertiodendron dewevrei) were used as reference because they are known to be strongly aggregated in recently disturbed patches (SLP) or along watercourses (G. dewevrei). Results show that SLP species are strongly aggregated with clear spatial autocorrelation of their diameter. This confirms that they colonized the patch following a one-time disturbance event. In contrast, LLP and NPLD species have random or weakly aggregated distribution, mostly without spatial autocorrelation of their diameter. This does not unambiguously confirm the “human disturbance” hypothesis. Alternatively, their abundance might be explained by their deciduousness, which gave them a competitive advantage during long-term drying of the late Holocene. Additionally, a canonical correspondence analysis showed that the observed LLP and NPLD distributions are not explained by environmental variables, strongly contrasting with the results for the reference species G. dewevrei, which is clearly aggregated along watercourses. We conclude that the abundance of LLP and NPLD species in Yangambi cannot be unambiguously attributed to past human disturbances or environmental variables. An alternative explanation is that present-day forest composition is a result of adaptation to late-Holocene drying. However, results are inconclusive and additional data are needed to confirm this alternative hypothesis.
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