University of Kisangani
  • Kisangani, Democratic Republic of the Congo
Recent publications
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.
Secondary forests constitute an increasingly important component of tropical forests worldwide. Although cycling of essential nutrients affects recovery trajectories of secondary forests, the effect of nutrient limitation on forest regrowth is poorly constrained. Here we use three lines of evidence from secondary forest succession sequences in central Africa to identify potential nutrient limitation in regrowing forests. First, we show that atmospheric phosphorus supply exceeds demand along forest succession, whereas forests rely on soil stocks to meet their base cation demands. Second, soil nutrient metrics indicate that available phosphorus increases along the succession, whereas available cations decrease. Finally, fine root, foliar and litter stoichiometry show that tissue calcium concentrations decline relative to those of nitrogen and phosphorus during succession. Taken together, these observations suggest that calcium becomes an increasingly scarce resource in central African forests during secondary succession. Furthermore, ecosystem calcium storage shifts from soil to woody biomass over succession, making it a vulnerable nutrient in the wake of land-use change scenarios that involve woody biomass export. Our results thus call for a broadened focus on elements other than nitrogen and phosphorus regarding tropical forest biogeochemical cycles and identify calcium as a scarce and potentially limiting nutrient in an increasingly disturbed and dynamic tropical forest landscape.
The world’s largest tropical peatland complex is found in the central Congo Basin. However, there is a lack of in situ measurements to understand the peatland’s distribution and the amount of carbon stored in it. So far, peat in this region has been sampled only in largely rain-fed interfluvial basins in the north of the Republic of the Congo. Here we present the first extensive field surveys of peat in the Democratic Republic of the Congo, which covers two-thirds of the estimated peatland area, including from previously undocumented river-influenced settings. We use field data from both countries to compute the first spatial models of peat thickness (mean 1.7 ± 0.9 m; maximum 5.6 m) and peat carbon density (mean 1,712 ± 634 MgC ha⁻¹; maximum 3,970 MgC ha⁻¹) for the central Congo Basin. We show that the peatland complex covers 167,600 km², 36% of the world’s tropical peatland area, and that 29.0 PgC is stored below ground in peat across the region (95% confidence interval, 26.3–32.2 PgC). Our measurement-based constraints give high confidence of globally significant peat carbon stocks in the central Congo Basin, totalling approximately 28% of the world’s tropical peat carbon. Only 8% of this peat carbon lies within nationally protected areas, suggesting its vulnerability to future land-use change.
Background : Following an outbreak of cases of vesicular-pustular rash with fever evocative of human monkeypox in Bas-Uélé province, Democratic Republic of Congo, surveillance was strengthened. Methods : Households with at least one active generalized vesicular-pustular rash case were visited, and contact and clinical history information was collected from all household members. Whenever possible, skin lesion were screened by PCR for the monkeypox virus, followed by the varicella-zoster virus when negative for the former. Results : PCR results were obtained for 77 suspect cases distributed in 138 households, of which 27.3% were positive for monkeypox, 58.4% for chickenpox, and 14.3% negative for both. Confirmed monkeypox cases presented more often with monomorphic skin lesions, on palms of hands, and on soles of feet. Integrating these three features into the case definition raised the specificity to 85%, but would miss 50% of true monkeypox cases. A predictive model fit on patient demographics and symptoms had 97% specificity and 80% sensitivity, but only 80% and 33% in predicting out-of-sample cases. Conclusion : Few discriminating features were identified and the performance of clinical case definitions was suboptimal. Rapid field diagnostics are needed to optimize worldwide early detection and surveillance of monkeypox.
Aquatic losses of nutrients are important loss vectors in the nutrient budgets of tropical forests. Traditionally, research has focused mainly on losses of inorganic nutrient forms, whereas the potential contribution of organic and particulate losses to the total nutrient export budget is much less constrained. In this study, we quantified full aquatic nitrogen (N) and phosphorus (P) exports, including inorganic, organic and particulate forms, from a moist tropical lowland forest and a semi-dry Miombo woodland forest within the Congo Basin. While particulate organic N (PON) was the highest N loss vector in the lowland stream (3.34 kg N ha⁻¹ y⁻¹; 44% of TN), dissolved organic N (DON) dominated the export in the Miombo stream (1.41 kg N ha⁻¹ y.−1; 47% of TN). Aquatic P export was dominated by dissolved organic P (DOP) in both streams, with yields of 0.29 kg P ha⁻¹ y⁻¹ (65% of TP) in the lowland and 0.24 kg P ha⁻¹ y⁻¹ (69% of TP) in the Miombo. Storm events were driving those losses, exporting disproportionally high N and P loads during short periods of stormflow conditions (32% and 47% of TN and 20% and 40% of TP in the lowland and Miombo, respectively). Our results highlight the need to take particulate and organic forms into account as important loss vectors in the nutrient balance of tropical forests. This finding is of particular importance considering the projected increasing rainfall intensities in many tropical regions which might exacerbate the export of these nutrient forms in the near future.
Background & objective: Sickle cell disease (SCD) is now a well-established cause of renal damage. In the northeast of the Democratic Republic of Congo (DRC), SCD is common. However, sickle cell nephropathy remains unstudied in this region. Thus, this study aimed to assess renal abnormalities in SCD patients in Kisangani (northeastern DRC). Methods: This cross-sectional study included 98 sickle cell patients selected from six health facilities in Kisangani and 89 healthy non-sickle cell subjects as the control group. Based on a survey form, a clinical examination and biological tests were performed to collect data related to the sex, age, weight, height, blood pressure, serum creatinine, serum uric acid, urinary albumin/creatinine ratio, and hemoglobin phenotype. We used a spectrophotometer to measure serum creatinine and uricemia, the sickle SCAN® device for hemoglobin phenotype, and an automatic multifunction analyzer for urine albumin/creatinine ratio. Data were entered into an Excel file and analyzed on SPSS 20.0. Results: The mean urine albumin-to-creatinine ratio was 11.79±9.03 mg/mmol in SCD patients, significantly higher than in AA (1.69±1.89 mg/mmol) and AS (2.97±4.46 mg/mmol) subjects. The decrease in glomerular filtration rate was more observed in SCD patients with hyperuricemia compared to those with normal uric acid levels. A significantly elevated prevalence of chronic kidney disease was observed among SCD patients (87.8%) compared to 23.8% in AS and 7.7% in AA subjects. Conclusions: This study highlighted that albuminuria and chronic kidney disease are common in SCD patients in Kisangani. More studies are needed to document these complications further. Keywords: Sickle cell disease, prevalence, sickle cell nephropathy, renal abnormalities, Democratic Republic of the Congo, sub-Saharan Africa.
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.
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126 members
Joris L Likwela
  • Department of Public Health
Mikwa Ngamba Jean-fiston
  • Forestry, Research Unit In Soil and Spatial Information systems ''RUSSIS''
Guy-Crispin Gembu Tungaluna
  • Ecologie et Gestion des Ressources Animales (Faculté des Sciences), Ecologie et Biodiversité des Ressources Terrestres (CSB)
Faustin Boyemba Bosela
  • Ecologie et Aménagement Forestier
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Kisangani, Democratic Republic of the Congo