Recent publications
The transition from current production systems to sustainable soil and crop management practices is imperative for meeting increasing demands. This shift is essential for minimizing environmental impacts while enhancing productivity and resource efficiency. In this context, the use of beneficial soil microorganisms such as arbuscular mycorrhizal fungi (AMF) represents a promising avenue. The roles of AMF in improving crop growth, yield, and biofortification have been scientifically established, both under normal and extreme conditions. Additionally, the role of AMF in enhancing soil fertility by improving its physical, chemical, and biological properties has been recently elucidated in several experimental studies in Sub-Saharan Africa. However, the effective establishment of symbiosis and its impact are closely regulated by various factors, including the genetic characteristics of crop and AMF species, as well as environmental conditions. The lack of control over these parameters reduces crops responsiveness to AMF, thus limiting the full agronomic potential of this symbiosis. This review presents scientific evidence of the benefits of AMF in enhancing soil fertility, increasing yields, and crop biofortification, while examining the underlying mechanisms. Finally, we have identified the knowledge gaps that should be addressed by future research for optimal integration of AMF into cropping systems.
There is growing research interest in the fall armyworm (FAW) Spodoptera frugiperda, a polyphagous insect that is a major pest of maize crops worldwide. We investigated the relationship between planting date of maize and FAW infestation in South Kivu, eastern Democratic Republic of Congo, in two sampling seasons (September to October 2020 and February to March 2021). Five planting dates were considered for 45 fields in each season. The incidence, severity of attack and larval density of FAW were assessed at the 8-leaf stage (V8) of maize development in monoculture and intercropping systems. Planting period, classified as late or early, had a strong influence on FAW larval density, incidence and severity. The results showed that the late planting period (mainly on 30 October in season-1 and 30 March in season-2) had the highest larval density, incidence and severity of attack compared to the early planting period (15 September in season-1 and 01 Mars in season-2). During the season-1, five larval stages were found in the same field, whereas all larval stages were present in season-2, regardless of planting period. High densities of L4, L5 and L6 larvae were much more associated with late planting and incidence appeared to be highest when these larvae were present. The presence of L2 and L3 larval stages was observed in maize cropping systems intercropped with soybean and peanuts, while maize in monoculture and intercropped with cassava and beans was colonized by L4, L5 and L6 larvae. This study highlights the existence of different maize planting dates in South Kivu and demonstrates that late plantings have significant FAW infestations compared to early plantings. It provides a basis for developing climate-smart integrated pest management.
Motherhood occurs early in the Democratic Republic of the Congo (DRC). According to the 2007 and 2013/2014 Demographic and Health Surveys (DHS), about 19 and 21% of adolescents had at least one child during adolescence. In addition, during the First and Second Congo Wars, schools were closed, and many school-age girls dropped out of school as a result. This study aimed to analyze the variation in the risk of adolescent motherhood according to the war phases in the DRC and the effect of war exposure during primary school on the risk of adolescent motherhood. This study used pooled 2007 and 2013/2014 DRC DHS data, including 28,822 women. A discrete-time event history model was used to analyze changes in the probability of adolescent motherhood during the war phases. The Cox model was used to analyze the effect of exposure to war during primary school on the risk of adolescent motherhood. The findings showed a decrease in the probability of adolescent motherhood during the First Congo War and an increase during the Second Congo War, with a stronger effect in the Kivu region. In addition, exposure to war during primary school was associated with an increased risk of adolescent motherhood, with a less pronounced effect in Kivu. Teenage marriage and early sexual activity were the main mechanisms through which exposure to war during primary school increased the risk of adolescent motherhood. The First and Second Congo Wars caused girls in the DRC to drop out of school, exposing them to early sexual debut and adolescent marriages, which ultimately led to adolescent motherhood. To reduce the prevalence of adolescent motherhood, girls in the DRC need to be followed up and supported to complete their primary education.
Dementia is a global public health issue, with 57.5 million people living with at least one type of dementia in 2019 worldwide, and projected to rise to 152 million by 2050.
Objective
We assessed the cognitive function in diabetic patients aged 60 or older in Bukavu city, in the eastern Republic of the Congo (DRC).
Methods
This case-control study involved 123 patients with established diabetes mellitus (DM) and 123 controls over 60-year-olds also with high rates of illiteracy. Cognitive function was assessed using the Swahili version of the Community Screening Instrument for Dementia (CSI-D).
Results
Foremost, our study revealed language-related differences between Swahili spoken in other eastern African countries such as Tanzania and Kenya, where the Swahili CSI-D is readily applied, compared to the Swahili spoken in Bukavu (DRC). Our results also showed that cognitive impairment was present in 18.7% of the total 246 participants. Remarkably, the prevalence rate of cognitive impairment was higher in the non-diabetic group (12.2 versus 25.2%; p=0.009). Participants aged 80 or older were more likely to present with cognitive impairment compared to those aged less than 80 (adjusted odds ratio — aOR=70.27; 95% confidence interval — 95%CI 3.94–125.15; p=0.004). We also found that patients living with DM for more than 20 years were three times more likely to be impaired compared to those who were recently diagnosed with DM (aOR=3.63; 95%CI 1.70–18.81; p=0.026).
Conclusion
This study revealed that cognitive impairment was relatively high in Bukavu city. It emphasizes the lack of effective tools to assess cognitive function. This requires, therefore, that research be adapted to the intellect and cultural experiences of the patients.
Keywords:
Cognitive Dysfunction; Dementia; Diabetes Mellitus; Neuropsychology; Africa
Background Hepatitis B virus (HBV) significantly impacts public health, particularly among individuals with Human Immunodeficiency Virus (HIV). Co-infection can worsen HBV progression and increase chronic liver disease risks. This study assesses HBV marker frequency, viral load, and associated factors in HIV patients in South Kivu to understand the health implications of HBV-HIV co-infection. Methods This cross-sectional study, from July 1, 2019, to July 30, 2021, included 864 HIV patients aged 18 to 70 from General Referral Hospital of Panzi, Regional Military Hospital of Bukavu, and Fomulac Hospital. Participants, on antiretroviral therapy or newly diagnosed, consented for blood testing for hepatitis B using enzyme-linked immunosorbent assay (ELISA) and viral loads using GeneXpert. Data were analyzed with Stata SE 14.0. Ethical approval was secured from National Health Ethics Committee (CNES001/DPSK/124PP/2019). Results The study found 8.0% HBsAg positivity among HIV patients in South Kivu, with 41.3% and 14.1% showing anti-HBc and anti-HBs antibodies, respectively. HBs positivity was linked to male gender (AOR = 2.96; p = 0.007), rural origin (AOR = 4.32; p = 0.014), treatment at Fomulac Hospital (AOR = 4.87; p = 0.002), marital status (AOR = 4.55; p = 0.036), lower education (AOR = 57.25; p = 0.002), jaundice history (AOR = 3.98; p = 0.021), and < 5 years of unprotected sex (AOR = 10.96; p = 0.002). The HIV viral load averaged 1807 ± 3698 copies/ml, with no significant difference between HIV-only and co-infected individuals (p = 0.6642). 58.0% on ART had undetectable HIV loads. For HBV, 43.5% had undetectable, 49.3% low, and 7.2% high viral loads. A correlation existed between HIV and HBV loads; undetectable HIV corresponded to undetectable HBV in 62.5%, and high HIV loads to high HBV in 50.0%. Conclusion High HBV co-infection rates in HIV-positive individuals in South Kivu necessitate regular HBV monitoring and integrated prevention, screening, and vaccination strategies in HIV care. Despite ART managing both infections effectively, further research on HBV-related outcomes is essential for improving co-infected patient care.
It is widely predicted that climate change’s adverse effects will intensify in the future, and along with inadequate agricultural practices, settlement development, and other anthropic activities, could contribute to rapid wetland degradation and thus exert significant negative effects on local communities. This study sought to develop an approach based on the Integrated Water Resource Management (IWRM) in the Ruzizi Plain, eastern Democratic Republic of Congo (DRC), where adverse effects of the climate change are increasingly recurrent. Initially, we analyzed the trends of climate data for the last three decades (1990–2022). Subsequently, the Water Evaluation and Planning (WEAP) approach was employed on two contrasting watersheds to estimate current and future water demands in the region and how local wetlands could serve as reservoirs to meeting water demands. Results indicate that the Ruzizi Plain is facing escalating water challenges owing to climate change, rapid population growth, and evolving land-use patterns. These factors are expected to affect water quality and quantity, and thus, increase pressure on wetland ecosystems. The analysis of past data shows recurrence of dry years (SPI ≤ − 1.5), reduced daily low-intensity rainfall (Pmm < 10 mm), and a significant increase in extreme rainfall events (Pmm ≥ 25 mm). The WEAP outcomes revealed significant variations in future water availability, demand, and potential stressors across watersheds. Cropland and livestock are the main water consumers in rural wetlands, while households, cropland (at a lesser extent), and other urban uses exert significant water demands on wetlands located in urban environments. Of three test scenarios, the one presenting wetlands as water reservoirs seemed promising than those considered optimal (based on policies regulating water use) and rational (stationary inputs but with a decrease in daily allocation). These findings highlight the impact of climate change in the Ruzizi plain, emphasizing the urgency of implementing adaptive measures. This study advocates for the necessity of the IWRM approach to enhance water resilience, fostering sustainable development and wetland preservation under changing climate.
The traditional crop calendar for yam (Dioscorea spp.) in South-Kivu, eastern Democratic Republic of Congo (DRC), is becoming increasingly inadequate given the significant climatic variability observed over the last three decades. This study aimed at: (i) assessing trends in weather data across time and space to ascertain climate change, and (ii) optimizing the yam crop calendar for various South-Kivu agro-ecological zones (AEZs) to adapt to the changing climate. The 1990–2022 weather data series were downloaded from the NASA-MERRA platform, bias correction was carried out using local weather stations’ records, and analyses were performed using RClimDex 1.9. Local knowledge and CROPWAT 8.0 were used to define planting dates for yam in different AEZs. Results showed the existence of four AEZs in the South-Kivu province, with contrasting altitudes, temperatures, and rainfall patterns. Climate change is real in all these South-Kivu’s AEZs, resulting either in rainfall deficits in some areas, or extreme rainfall events in others, with significant temperature increases across all AEZs. Suitable yam planting dates varied with AEZs, September 15th and 20th were recommended for the AEZ 2 while October 15th was optimal for AEZ 1, AEZ 3, and AEZ 4. However, none of the planting date scenarios could meet the yam water requirements in AEZ1, AEZ3, and AEZ4, since the effective rainfall (Pmm) was always inferior to the plant water demand (ETc), meaning that soil water conservation practices are needed for optimum plant growth and yield in these AEZs. This study does not recommend planting yam during the short rainy season owing to prolonged droughts coinciding with critical growth phases of yam, unless supplemental irrigation is envisaged. This study provided insights on the nature of climate change across the past three decades and suggested a yam crop calendar that suits the changing climate of eastern DRC.
Extracellular vesicles (EVs) are heterogeneous, phospholipid membrane enclosed particles that are secreted by healthy and cancerous cells. EVs are present in diverse biological fluids and have been associated with the severity of diseases, which indicates their potential as biomarkers for diagnosis, prognosis and as therapeutic targets. This study investigated the phenotypic characteristics of EVs derived from peripheral blood (PB) and bone marrow (BM) in pediatric patients with B-cell acute lymphoblastic leukemia (B-ALL) during different treatment stages. PB and BM plasma were collected from 20 B-ALL patients at three time points during induction therapy, referred to as: diagnosis baseline (D0), day 15 of induction therapy (D15) and the end of the induction therapy (D35). In addition, PB samples were collected from 10 healthy children at a single time point. The EVs were measured using CytoFLEX S flow cytometer. Calibration beads were employed to ensure accurate size analysis. The following, fluorescent-labeled specific cellular markers were used to label the EVs: Annexin V (phosphatidylserine), CD235a (erythrocyte), CD41a (platelet), CD51 (endothelial cell), CD45 (leukocyte), CD66b (neutrophil), CD14 (monocyte), CD3 (T lymphocyte), CD19, CD34 and CD10 (B lymphoblast/leukemic blast). Our results demonstrate that B-ALL patients had a marked production of EV-CD51/61⁺, EV-CD10⁺, EV-CD19⁺ and EV-CD10⁺CD19⁺ (double-positive) with a decrease in EV-CD41a⁺ on D0. However, the kinetics and signature of production during induction therapy revealed a clear decline in EV-CD10⁺ and EV-CD19⁺, with an increase of EV-CD41a⁺ on D35. Furthermore, B-ALL patients showed a complex biological network, exhibiting distinct profiles on D0 and D35. Interestingly, fold change and ROC curve analysis demonstrated that EV-CD10⁺CD19⁺ were associated with B-ALL patients, exhibited excellent clinical performance and standing out as a potential diagnostic biomarker. In conclusion, our data indicate that EVs represent a promising field of investigation in B-ALL, offering the possibility of identifying potential biomarkers and therapeutic targets.
Objective
The goal was to understand how children born of rape in the Democratic Republic of Congo induce parental stress and how parents work together to care for these children.
Background
Abundant literature is devoted to children born of rape, but nothing is known about the stress undergone by their parents in the care process.
Method
Twenty‐four rape survivor couples and 26 control couples with children aged 6–17 were subjected to Parenting Alliance Inventory (PAI) and Parenting Stress Index (PSI) tests in the east part of the Democratic Republic of Congo.
Result s
The parental alliance of the rape survivor couples was comparable to that of the controls. However, for survivor couples, mothers received more support from their husbands for girls than for boys. Parental stress was low among fathers. It was high among mothers of boys and low among fathers of girls. Finally, it was high among mothers of boys compared with fathers.
Conclusion
Boys born of rape induce high parental stress compared with girls born of rape, and mothers experience more stress than fathers.
Implications
Support programs for families of rape survivors must be gender specific for both parents and children, and preferably a family‐centered approach should be considered.
Understanding the typology of smallholder maize farmers is crucial to elucidate the diversity in local farming systems, and therefore, devise effective interventions and policies that maximize the impact of agricultural innovations in South-Kivu province, eastern Democratic Republic of Congo (DRC). This study aimed at characterizing maize farmers in South-Kivu province and clustering them based on various socioeconomic and agronomic factors to identify specific production constraints and devise more effective interventions. A household survey among 300 South-Kivu maize farmers allowed to identify four distinct clusters based on farm size, land use, income, and agricultural technology adoption. The clusters ranged from resource-poor smallholder (Types 1 and 2) to medium-resource semi-innovative producers (Type 3) and highly equipped innovative farmers (Type 4). Key discriminative factors included total farm size, maize farm size, farming experience, access to agricultural credit, income, and innovation adoption rate. This study revealed specific constraints for each cluster, including low soil fertility, poor weed management, low market access, and labor scarcity. This study’s findings demonstrate the value of farm typology in guiding targeted interventions to address specific constraints and improve maize productivity, and suggest specific strategic directions for research and development projects in rural
areas of the South-Kivu province.
Livestock production in South Kivu is a major source of rural income. Increasing livestock productivity through improved livestock feeding is critical to alleviating poverty among smallholder farmers. The study aims to provide evidence-based recommendations for improving livestock productivity in South Kivu. It assesses the availability and use of feeds for livestock in Kabare, Uvira and Walungu. Current feeding practices are traditional, resulting in suboptimal animal nutrition. Livestock diets consist mainly of fodder and crop residues. Different botanical families provide essential fodder for livestock in the region. Disparities in forage availability affect animal nutrition and productivity, requiring targeted interventions. Additionally, a comprehensive SWOT and NOISE analysis were conducted to assess the current state and potential approaches for improving livestock feeding practices. Strengths include farmers' expertise and strategies to cope with forage scarcity, particularly in the dry season. Weaknesses include limited land tenure and limited adoption of intensive systems. Opportunities include diversification of food sources and farmer training. Challenges include climate variability and socioeconomic constraints. Proposed improvements focus on feed quality, nutritional supplements, and training. Strategic actions include policy advocacy and community involvement. Exceptions highlight the importance of tailoring practices to local contexts.
Edible insects are perceived as an incredible opportunity to mitigate the major challenge of sustainably producing healthy foods for a growing world population in the face of climate change uncertainties over the coming decade. In this study, we assessed the nutrient composition and sensory properties of Acheta domesticus, Apis mellifera, Gnathocera trivittata, Gryllotalpa africana, Imbrasia epimethea, Imbrasia oyemensis, Locusta migratoria, Macrotermes subhylanus, Nomadacris septemfasciata, Rhyncophorus phoenicis, Ruspolia differens and Rhynchophorus ferrugineus consumed in Eastern D. R. Congo. The investigated edible insects are highly appreciated and nutritious, with proteins (20.67–43.93 g/100 g) and fats (14.53–36.02 g/100 g) being the major macro-nutrients, proving their potential to improve diets through food enrichment. The high potassium (24–386.67 mg/100 g), sodium (152–257.82 mg/100 g), magnesium (32–64 mg/100 g), iron (5.3–16.13 mg/100 g), calcium (25–156.67 mg/100 g) and zinc (11–19.67 mg/100 g) content make the assessed edible insects a useful mineral-containing ingredient for preventing undernutrition in countries which are plagued by micronutrient deficiencies. A scatter plot of matrices and Pearson’s correlations between sensory attributes and nutritional composition showed a negative correlation (r = − 0.45) between protein and appearance. While no strong correlation was observed between nutritional attributes and sensory acceptance, a positive correlation was observed between potassium and aroma (r = 0.50), after-taste (r = 0.50) and acceptability (r = 0.52). Principal component analysis results indicated that the two axes accounted for up to 97.4% of the observed variability in the nutrient composition and sensory attributes of commonly consumed edible insects in the Eastern D. R. Congo. Given the significant delicacy and nutritional potential of edible insects highlighted in this paper, households can rely on the latter to meet their nutritional needs rather than conventional livestock, thus contributing to environmental and financial security through local business opportunities.
Introduction
Limited data are available on the prevalence rates of hepatitis B and acquired immunodeficiency syndrome (AIDS) among women survivors of sexual violence (WSSV) in South Kivu province, in the eastern part of the Democratic Republic of Congo (DRC), where armed conflicts persist. Here, we aimed to assess the prevalence of these two infections in this vulnerable local population.
Methods
A total of 1002 WSSV, aged from 18 to 70 years old were enrolled from May 2018 to May 2020 at three healthcare facilities (Panzi, Mulamba and Bulenga hospitals), which are called “The One-Stop Centre Care Model" for the management of sexual violence in South Kivu. Blood samples were collected and tested for hepatitis B virus (HBV) and human immunodeficiency virus (HIV) antigens and antibodies using enzyme-linked immunoassay (ELISA) methods. Subsequently, viral load quantification for HBV and HIV were performed using the GeneXpert. Univariate and multivariate logistic regression models were used to assess factors associated with HIV-positive and HBV-positive status.
Results
For HBV, overall prevalence was 8.9% (95% CI; 7.2–10.8%), 32.1% (95% CI; 29.3–35.0%), and 14.5% (95% CI; 12.3–16.8%) for HBsAg, anti-HBc and anti-HBs antibodies, respectively. Among the 89 HBsAg-positive patients, 17 (19.1%) were HBeAg-positive. The median age of individuals with a positive HBsAg test was higher than those with a negative test (median: 40 years (IQR 30–52) compared to 36 years (IQR 24–48)). Risk factors for HBV infection were age (≥35 years) (AOR = 1.83 [1.02–3.32]; p = 0.041), having no schooling (AOR = 4.14 [1.35–12.62]; p = 0.012) or only primary school-level (AOR = 4.88 [1.61–14.75]; p = 0.005), and multiple aggressors (AOR = 1.76 [1.09–2.84], p = 0.019). The prevalence of HIV was 4.3% [95% CI: 3.1–5.7%]. HIV/HBV co-infection occurred only in 5 individuals (0.5%). The HBV viral load was detectable (> 1 log10 UI/mL) in 61.8% of HBsAg-positive subjects and 64.8% HIV-positive subjects had a high viral load (≥ 3 log10 copies/mL).
Conclusion
This study revealed a high prevalence of HBV and HIV infections among WSSV in South Kivu. The results generated highlight the urgent need for systematic screening of HBV and HIV by integrating fourth-generation ELISA tests in HIV and HBV control programs.
Background
Studies on fertility desires among fistula patients in the Democratic Republic of Congo (DRC) have been conducted on fewer patients. Furthermore, these studies have adopted a univariate descriptive approach. This study aims to examine the determinants of fertility desires among patients with fistula in the DRC.
Methods
This cross-sectional study included women aged 15–49 whose fistulas were repaired by the Panzi Hospital mobile team in seven DRC regions between 2013 and 2018. Univariate and bivariate descriptive analyses were performed using the frequency distribution table and the chi-square test. Adjusted odds ratios with their 95 confidence intervals from logistic regression were used to analyze factors associated with fertility desire after fistula repair. All analyses were stratified by parity level for all women aged 15–49 and 20–34 years.
Results
Of the 1,646 women aged 15–49 and 808 aged 20–34, 948 (57.6%) and 597 (73.8%), respectively, wanted to have children after fistula repair. Among women aged 15–49 and 20–34 years, the desire to have children was parity-specific. It was negatively associated with age at all parity levels. In women with low parity, the desire for children was significantly negatively associated with a high number of surgeries, abortions, and fistula duration. It tended to decrease with time, but was particularly high in 2014 and 2017. It was high among the Protestant women. Among medium-parity women, it was significantly lower in urban areas and among widows, but higher among women who had more than two abortions. Among high-parity women, it was negatively associated with education level.
Conclusion
To help women with fistula achieve or approach their desired number of children, our findings suggest that (1) counseling is needed for women with a high desire for children; (2) the human, material, and financial resources needed to eliminate fistula in the DRC should be made available; and (3) medical and nursing staff should be sufficiently and effectively trained to minimize the number of unsuccessful surgeries performed on women with fistula.
Random forests (RF) have been widely used to predict spatial variables. Several studies have shown that spatial cross-validation (CV) methods consistently cause RF to yield larger prediction errors compared to standard CV methods. This study examined the impact of species characteristics and data features on the performance of the standard RF and spatial CV approaches for predicting species abundance distribution. It compared the standard 5-fold CV, design-based validation, and three different spatial CV methods, such as spatial buffering, environmental blocking, and spatial blocking. Validation samples were randomly selected for design-based validation without replacement. We evaluated their predictive performance (accuracy and discrimination metrics) using artificial species abundance data generated by a linear function of a constant term (β0) and a random error term following a zero-mean Gaussian process with a covariance matrix determined by an exponential correlation function. The model was tuned over multiple simulations to consider different mean levels of species abundance, spatial autocorrelation variation, and species detection probability. Here we found that the standard RF had poor predictive performance when spatial autocorrelation was high and the species probability of detection was low. Design-based validation and standard K-fold CV were found to be the most effective strategies for evaluating RF performance compared to spatial CV methods, even in the presence of high spatial autocorrelation and imperfect detection for random samples. For weakly or moderately clustered samples, they yielded good modelling efficiency but overestimated RF’s predictive power, while they overestimated modelling efficiency, predictive power, and accuracy for strongly clustered samples with high spatial autocorrelation. Globally, the checkerboard pattern in the allocation of blocks to folds in blocked spatial CV was found to be the most effective CV approach for clustered samples, whatever the degree of clustering, spatial autocorrelation, or species abundance class. The checkerboard pattern in spatial CV was found to be the best method for random or systematic samples with spatial autocorrelation, but less effective than non-spatial CV approaches. Failing to take data features into account when validating models can lead to unrealistic predictions of species abundance and related parameters and, therefore, incorrect interpretations of patterns and conclusions. Further research should explore the benefits of using blocked spatial K-fold CV with checkerboard assignment of blocks to folds for clustered samples with high spatial autocorrelation.
Damage caused by pests and diseases is one of constraints on crop production for food security. Based on the use of questionnaire and interviews that were conducted in Kabare territory (South-Kivu), this study was carried out to (i) assess farmers practices, attitudes, and knowledge about pesticides use, and (ii) assess the human health and physical environment effects using pesticides.Data was collected from 300 small-scale farmers in study area. Results showed that majority of our respondents were men (59 %) rather than women (41 %) and local knowledge of pesticide use was low (60 %). Education level had a significant influence (p < 0.01) on level of knowledge about pesticide use, time and dose of treatment, method of control, and persistence time. In addition, education level influence significantly farmers’ attitudes before and after pesticide treatment (p < 0.05). Pest management control, time of pesticide application, and packaging management method varied significantly with level of local knowledge (p < 0.01). Pesticides use by small-scale farmers has an effect on water, soil, and air quality. It also causes human pathologies such as vomiting, eye irritation, and even loss of life in event of heavy exposure. Inhalation and dermal exposure are main and most dangerous routes of pesticide exposure in ourstudy area, which lacks protective strategies. Finally, use of pesticides disrupts biodiversity through the disappearance of pollinators, predators, parasitoids, and soil microorganisms.Therefore, broad continuity of this study with integration of other scientific aspects would effectively contribute to the improvement of environmental quality.
For informed decision-making in biodiversity conservation and ecological management, accurate predictions of species abundance are essential. This study aimed to assess the predictive performance of random forest (RF) spatial variants in modelling species abundance distribution compared to standard RF, Poisson, their hybrid methods with ordinary kriging (OK), and the random generalised linear model (RGLM). Model performance in abundance modelling has rarely been quantified using a comprehensive index, except the existing single statistical indices. Therefore, modified Taylor diagrams were used to evaluate the model’s overall ability to predict species abundance spatial patterns, taking into account abundance class and detection probability. An exponential correlation function was used to generate spatially correlated random effects with and without a quadratic term and two variation strengths. Species abundance class and the relationship between abundance and independent variables determine which RF spatial variant performs the best. Spatial RF variants outperform conventional modelling in terms of prediction accuracy and power, particularly when spatial autocorrelation and species detection probabilities are high. RF spatial variants were less precise for common species than RGLM and GLM-OK, which better predicted species abundance for low or no spatial autocorrelation cases. However, none of the models outperformed the others for all prediction goals, highlighting the need for combining performance metrics to evaluate species abundance distribution models. The study highlights the importance of model specification in ecological research and cautions against the use of RF algorithms as a black box.
This study focused on quantifying and valorizing domestic waste in Bukavu, a rapidly growing city in eastern Democratic Republic of Congo (DRC). With increasing anthropogenic pressure, waste management has become a pressing issue, yet documentation in this area is still limited. This study aimed to fill this gap by providing comprehensive data on domestic waste generation, composition, and disposal practices in Bukavu city. Through field surveys and analysis, waste quantities and types were documented, revealing significant challenges in waste management infrastructure and practices. Additionally, the study explores opportunities for waste valorization, particularly through composting, given the region's agricultural potential and growing urban food demand. The findings revealed that ~ 5% of the domestic waste is biodegradable, with the majority consisting of metals and plastics. These wastes are predominantly used as livestock feed (10%), incinerated (66%), or buried (17%), with ~ 5% undergoing composting. Waste management is primarily handled by children (82%), with very few non-governmental organizations (NGOs) involved in such activities. Among the three composting methods evaluated, outputs from vermicomposting demonstrated superior qualities in terms of promoting crop growth, increasing yield, and achieving a high germination index. Overall, the application of composts improved plant growth and yield parameters of the two major legumes (common bean and soybean). Future interventions should explore the implementation of large-scale composting units at the household or citywide level, while also considering additional strategies to enhance the quality of the compost products. Such efforts are crucial in mitigating the environmental and health impacts of urban household waste and promoting sustainable practices in urban agriculture.
Background
The Central African Republic (CAR) is one of the countries with the highest prevalence of viral hepatitis infection in the world. Coinfection with HIV increases the morbidity and mortality beyond that of mono-infection with either hepatitis or HIV. The present study describes the geographic distribution of viral hepatitis infections and molecular characterization of these viruses in the CAR.
Methodology
Out of 12,599 persons enrolled during the fourth Multiple Indicator Cluster Survey of 2010 in the CAR, 10,621 Dried Blood Spot (DBS) samples were obtained and stored at -20°C. Of these DBS, 4,317 samples were randomly selected to represent all regions of the CAR. Serological tests for hepatitis B, D, and C viruses were performed using the ELISA technique. Molecular characterization was performed to identify strains.
Results
Of the 4,317 samples included, 53.2% were from men and 46.8% from women. The HBsAg prevalence among participants was 12.9% and that HBc-Ab was 19.7%. The overall prevalence of HCV was 0.6%. Co-infection of HIV/HBV was 1.1% and that of HBV/HDV was 16.6%. A total of 77 HBV, 6 HIV, and 6 HDV strains were successfully sequenced, with 72 HBV (93.5%) strains belonging to genotype E and 5 (6.5%) strains belonging to genotype D. The 6 HDV strains all belonged to clade 1, while 4 recombinants subtype were identified among the 6 strains of HIV.
Conclusion
Our study found a high prevalence of HBV, HBV/HDV and HBV/HIV co-infection, but a low prevalence of HCV. CAR remains an area of high HBV endemicity. This study’s data and analyses would be useful for establishing an integrated viral hepatitis and HIV surveillance program in the CAR.
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Bukavu, Democratic Republic of the Congo