Centre Region Of Cameroon Research Articles

Epidemiological analysis of the incidence of COVID-19 among the population of the Republic of Cameroon using the quantum Geographic Information System (QGIS)

The results of a retrospective epidemiological analysis of the incidence of COVID-19 in the regions of the Republic of Cameroon in dynamics from 2020 to 2023 are presented. It was noted that COVID-19 cases were first reported in the Central Region of Cameroon, and then spread to the remaining 9 administrative regions of the country with an average weekly growth rate of 38.1 ± 18.6% in 2020, 15.3 ± 13.1% in 2021, and 13.4 ± 12.2% in 2022, respectively, however, the incidence rate varied significantly in time and space. Epidemiological analysis made it possible to rank the territory of Cameroon by the magnitude of the incidence rate. The highest rate was recorded in the North region (233.1‰), in the Coastal region (204.9‰) and in the Center region (173.7‰). The regions of Adamawa and the Far North had the lowest incidence rates (25.6‰ and 22.5‰, respectively). The results of a comparative analysis of the incidence of COVID-19 infection by time and territory and factors contributing to the rapid spread of infection are presented. Comparative mapping of reported COVID-19 cases in space and time was performed for the 10 administrative regions of the country using the full version of the QGIS (quantum GIS) LTR program; with the help of which the distribution of cases across the territory and dynamics over time was clearly shown. During the study period, the link between COVID-19 cases reported in Cameroon and neighboring African countries was demonstrated. It has been shown that the distribution of cases in the national territory does not always depend on the population density in administrative areas, but is also associated with other risk factors that may affect the occurrence and spread of COVID-19 cases.

Zootechnical Factors Affecting the Biosecurity Profile of Fish Farms in the Centre Region of Cameroon

In order to optimize the fish production by a better knowledge of preventive measures against fish diseases, a cross-sectional audit was carried out in Cameroon from March to April 2022 on the zootechnical factors affecting the biosecurity practice in fish farms from the Centre Region (3°55'- 4°67'N; 9°46-11°52'E). A total of 50 farms were selected using the "snowball" method, face-to-face interview of fish farmers using a semi-structured questionnaire and direct observation. The most practiced farming system was the semi-intensive production system (74%), non-integrated fish farming (100%), grow-out (66%), monoculture (54%), and the soil system (34% of farms with ponds). The compliance rate (40.98%) and adoption rate (41.00%) of biosecurity measures (BM) was intermediate. The most adopted BM were "sanitary lock" and "no exchange of materials with other farms", while the least adopted were "veterinary intervention", "dead fish incinerated" and "special outfit for visitors". The BM were significantly more observed in intensive, nursery farms and those whose culture facilities were fastanks + concrete tanks with 3 to 12 production cycles per year. A strong, positive and significant linear relationship was established between the compliance rate (y) and BM such as the protection of farms from wild animals, quarantine of new fish, number of production cycles per year (x). The linear regression model between y and x was y = 4.65x - 0.0417. The capacity of fish farmers should be built on biosecurity practices. Key words: Biosecurity practice, diseases, mortality, fish, Cameroon

Uses, Structures, and Biomass of Some Stands of Bambusa Vulgaris Schrad, ex J.C. Wendl in the Center Region of Cameroon

Uses, Structures, and Biomass of Some Stands of Bambusa Vulgaris Schrad, ex J.C. Wendl in the Center Region of Cameroon

Exposure to bovine livestock and latent tuberculosis infection in children: Investigating the zoonotic tuberculosis potential in a large urban and peri-urban area of Cameroon.

Bovine tuberculosis (bTB), a neglected zoonotic disease, is endemic in cattle in many Sub-saharan African countries, yet its contribution to tuberculosis (TB) burden is understudied. Rapid urbanisation and increase in demand for animal proteins, including dairy products, increases the risk of spill over. This study compared the latent tuberculosis infection (LTBI) risk in children, a proxy-measure for recent TB infection, in children living in high cattle density areas to children from the general population in Cameroon. Cross-sectional study in the Centre Region of Cameroon in 2021, recruiting 160 children aged 2-15 years, stratified by exposure to livestock, people treated for pulmonary TB (PTB) and the general community. Veinous blood was tested for LTBI using QuantiFERON-TB Gold-Plus. Prevalence were calculated and the association to exposure and other risk factors investigated using logistic regression models. The crude LTBI prevalence were 8.2% in the general population, 7.3% in those exposed to cattle and 61% in pulmonary TB household contacts. After adjusting for confounding and sampling design, exposure to cattle and exposure to pulmonary TB were associated with higher risk of LTBI than the general population (respectively odds ratio (OR): 3.56, 95%CI: 0.34 to 37.03; and OR: 10.36, 95%CI: 3.13 to 34.21). Children frequently consuming cow milk had higher risk of LTBI (OR: 3.35; 95%CI 0.18 to 60.94). Despite limited statistical power, this study suggests that children exposed to cattle in a setting endemic for bTB had higher risk of LTBI, providing indirect evidence that Mycobacterium bovis may contribute to TB burden.

Assessment of Woody Species Biodiversity and Carbon Stock Potentials in the Arboretum of National School of Water and Forests of Mbalmayo, Center Region of Cameroon

Assessing forest biodiversity is crucial for supporting sustainable forest planning. We investigated the potential for biodiversity and carbon sequestration in both artificial and natural forests of the arboretum of the National School of Water and Forests (ENEF) of Mbalmayo. A floristic inventory was carried out in 72 plots measuring 25m x 25m in the artificial forest covering an area of 4.5ha, and in a quadrat measuring 250m x 180m in the natural forest of the arboretum. Carbon stocks were determined by the non-destructive method using allometric equations. The results of the woody biodiversity inventories identified 77 species belonging to 69 genera and 33 families. This species richness varied from 69 species in the natural forest to 58 species in the artificial forest. Tree density was slightly higher in the artificial forest (616 ±339 ind/ha) than in the natural forest (312 ±176 ind/ha), without being significantly different. Basal area was constant in both types of forest studied, with an average of 55.97 ±36.28 m2/ha in the artificial forest and 58.33 ±19.42 m2/ha in the natural forest. The greatest quantity of sequestered carbon was found in the natural forest with 432±146.49 tC/ha compared with 400.69±328.37 tC/ha in the artificial forest. Nevertheless, these rates were not significantly different according to the ANOVA test. Given the importance of this massif in carbon sequestration and the needs of local populations, ENEF should support these populations in agroforestry practices and in the domestication of priority tree species.

Rainforest Alliance-UTZ cocoa certification scheme adoption: Determinants and financial implications for cocoa production in the Centre region of Cameroon

This study evaluates the level of adoption of the Rainforest Alliance-UTZ cocoa certification scheme in the Centre region of Cameroon, ascertains the drivers of adoption, and evaluates the financial implications of the levels of adoption. Using cross-sectional data obtained from 100 cocoa growers in the Central region of Cameroon and employing a Generalised Ordered Logit estimation technique alongside a one-way ANOVA test and Tukey’s test for post-hoc estimations, we show that 50%, 17%, and 33% of cocoa growers are complete adopters, partial adopters, and non-adopters of the Rainforest Alliance-UTZ cocoa certification scheme, respectively. The findings also reveal that the likelihood of having partial or complete adoption is higher among farmers who have introduced orange trees in their orchards, own more extensive orchards, and have more years of experience in cocoa farming. Furthermore, the likelihood of having complete adoption is higher for farmers with a lower planting density in their orchards and a tertiary level of schooling. Farmer’s age has a mitigated effect on the likelihood of adopting certification schemes by reducing the likelihood of having partial or complete adoption against non-adoption and at the same time raising the likelihood of complete adoption against no or partial adoption. The study also concludes that the financial performance of cocoa growers varies based on their level of adoption of the Rainforest Alliance-UTZ certification scheme. Farmers who have achieved certification status tend to have higher farm earnings. Based on these findings, non-adopters and partial adopters are encouraged to fully adhere to the Rainforest Alliance-UTZ certification standards. By doing so, they can increase their financial gains, enhance their livelihoods, and reduce the negative environmental impacts of cocoa farming.

Nesting ecology of chimpanzee (Pan troglodytes) in the Yoko Council Forest, Centre Cameroon: assessing nest characteristics and decay rate

ABSTRACT Lack of data on the population size of chimpanzees (Pan troglodytes) in the Yoko Council Forest (YCF), located in the Centre region of Cameroon has hindered the ability to develop conservation measures. The sustainable management of this species requires reliable knowledge of their ecology, habits and resource needs. This study was conducted from February–July 2022 to assess nesting ecology and to use nest decay rates to estimate population size. The retrospective method for studying the degradation of animal indices was used. The mean nest decay rate was 77.5 days and density was estimated at 69.3 [54.9 86.7] nests/ km2 to 113 chimpanzees per km2. We also found a high preference for nests in specific forest types, with 92% of nests in marantaceous forests, and a preference for nests to be on Khaya grandifolia (Meliaceae) (28.24%) or Uapaca guinensis (Euphorbiaceae) (27.06%) trees. The preferential position for construction of chimpanzee nests was on a branch (58.82%) as opposed to in a branch fork (40.39%), which is interesting since one would assume a fork would offer more nest stability. Our study offers crucial insights that can guide policymakers in formulating targeted conservation strategies for the substantial chimpanzee population in the YCF.

Lithological Impact on Radon Levels: A Study of Indoor and Soil Gas Radon in the Centre Region of Cameroon

AbstractThe objectives of the current study are to carry out soil gas radon (Rn) measurements, to evaluate the total inhalation effective dose, to determine risk levels over the lithological formations of the study area. The behavior investigation of Rn activity concentration distributions in dwellings and soils, and soil Rn mapping were also conducted. Soil gas Rn measurements were made at 102 sampling points by Markus 10 instrument. This data was combined with previously reported results from 140 indoor Rn RADTRAK dosimeters to determine the total inhalation effective dose and to conduct a statistical analysis. Overall, the Rn activity concentrations in soil and dwellings range from 4 to 66 kBq m−3 and from 15 to 140 Bq m−3, with averages of 31 ± 15 kBq m−3 and 41 ± 24 Bq m−3 respectively. The corresponding total inhalation effective dose ranges from 0.35 to 3.53 mSv y−1, with a mean value of 1.37 ± 0.58 mSv y−1. For soil gas Rn, the chlorite schist lithology showed the highest average concentration level. Which could be justified by the possible presence, within chlorite minerals, highly emitting zones of alpha particles, leading to the formation of radioactive halos. Normal and high‐risk level of Rn were found for about 82% and 11% of the total area surveyed respectively. These findings highlight the need for preventive measure against Rn exposure in homes within the investigated areas. This study contributes valuable insights into Rn distribution patterns and risk assessment, offering a basis for targeted interventions in the region.

Factors affecting decision-making to strengthen climate resilience of smallholder farms in the Centre region of Cameroon

This study examined the resilience to climate change of smallholder family farms in the Centre Region of Cameroon. Data were collected using a mixed-methods strategy and analyzed using descriptive, multivariate, and inferential statistics. Family farms exhibited a mean climate resilience index of 0.46 (medium), with the Ntui, Mbangassina, Batchenga, and Obala regions scoring 0.42, 0.44, 0.47, and 0.51, respectively. Family farmers had a high transformation capacity (59.07 ​%), a low adaptation capacity (32.10 ​%), and a very low absorption capacity (8.82 ​%). Logistic regression revealed significant causal relationships (p ​< ​0.05) between the capacity of the farms to adapt to climate fluctuations and change and annual income, access to agricultural inputs, access to agricultural machinery, and membership in a farmers organization. These are the primary factors that could significantly increase climate resilience in Cameroonian family farms. Consequently, policymakers in these regions and beyond should consider these as indicators when developing policies to strengthen the climate resilience of local agricultural systems. In doing so, they should also consider community monitoring and indigenous knowledge, which can help bridge the gap between local adverse impacts and the necessary adaptations to climate change.

Elaboration of the Land use Land Cover Plan of the Subdivision of Monatele in Cameroon

Over the past years, humans have directly or indirectly affected the Earth’s surface through various activities. These changes in terrestrial ecosystems are closely linked with the issue of the sustainability of socio- economic development since they affect essential parts of our natural capital such as climate, soils, vegetation, water resources and biodiversity. Land Cover has undergone several changes in Cameroon since its independence in 1960. One of the major drivers of this change is urbanization. Uncontrolled, rapid urbanization has had many negative impacts on the center region of Cameroon, around the continuum of its headquarter and in Cameroon metropolises such as anarchical constructions, pollution and traffic congestions. Faced with these urbanization issues, planners need to know the spatiotemporal trends of Land Use Land Cover for the past, present and have predictions of possible future patterns in order to better orient their planning. This is possible through the establishment of Land Use Land Cover maps. Remote sensing and Geographic Information Systems represent a cost-effective method for accomplishing this. In this work, we examine the case of Monatélé, a growing city around the Yaoundé metropolis. Satellite images from 2010, 2017, 2022 were downloaded and classified into five classes using the Support Vector Machine algorithm of image classification. It was found that between 2010 and 2022, settlements have increase continuously from 1.61% to 4.28%, water has decreased continuously from 9.81% to 6.72%, forest has experienced a net decrease from 73.77% to 68.25%, agriculture has experienced a net increase from 12.44% to 16.92%, while Bare Land has had a net increase from 2.38% to 3.82%. of the total surface area of the subdivision of Monatélé. Predictions made for 2029 and 2035 show that by 2035, settlements would have increased to 6.58%, water would have decreased to 4.58%, forest would have decreased to 61.22%, agriculture will take 25.19%, and bare land would have almost remained unvaried, taking up 2.43% of the surface area from 2010 to 2035. This will represent for Monatélé an increase in anarchical settlements, an increased loss in biodiversity, an increased pollution, an increase in demand for basic commodities, and an increased pressure on natural resources, if no planning measures are put in place, though it may represent an increase in human capital, an increase in local employment opportunities, a reduction of groceries expenditures.

Ethnobotanical investigation of nutraceuticals used in the Nyong and Kelle Division, Centre Region, Cameroon

This study presents an ethnobotanical investigation of nutraceuticals plants used by the people of the Nyong and Kelle Division, in the Centre Region of Cameroon, to address various ailments. A systematic survey was conducted in ten markets and ten villages, where food traders were interviewed using a semi-structured questionnaire to gather information on the medicinal uses of plants. Traditional healers, elders, and community members validated the collected information. A total of 56 plants with medicinal properties were identified, categorized as 30 fruit trees, 19 vegetables, and 7 spices, belonging to 32 botanical families. The Anacardiaceae and Solanaceae families were the most represented. These nutraceuticals were found to treat 28 different illnesses, with the leaves being the most commonly used plant organ. Decoctions were the primary therapeutic indication, and digestive system-related ailments were prevalent. This research contributes to the preservation and dissemination of ethnobotanical knowledge inherited from previous generations.

Demographic, Behavioural and Clinical Characteristics of HIV-infected Adults Initiating Antiretroviral Therapy in Rural ART Clinics in the Centre Region of Cameroon

Despite considerable progress in the scale-up of antiretroviral therapy programs in Cameroon, disparities persist between urban and rural settings. Understanding the characteristics of rural populations is crucial for designing effective, context-specific interventions that address barriers to early HIV care engagement. A retrospective cohort study was conducted of all HIV infected adults who initiated ART at 10 rural ART clinics in the Centre Region of Cameroon between June 2020 and May 2021. Patients’ medical records were reviewed for data collection. Of the 2 591 HIV infected adults included in the analysis, 983 (37.9%) were males and 1 608 (62.1%) females. Mean age at initiation was 38.91 ± 11.41 years with statistically significant difference between genders (p = 0.0002). A higher percentage of females (34.8%) initiated care in the 21-30 years age group than males (18.6%) (χ² = 87.163, p &lt; 0.0001). More females initiating ART had no formal education (10.3%) or primary education (42.3%) compared to their male counterparts (8.1% and 40.7%, respectively) (χ² = 13.213, p=0.021). Females (56.7%) were more likely not to disclose their HIV status to their partners than males (53.2%) (χ² = 9.380, p = 0.009*). Moreover, more females (71.1%) compared to males (41.1%) initiated ART with TDF/3TC/DTG (χ² = 35.509, p &lt; 0.0001*). The findings from the study show the complexity of demographic, behavioural and clinical factors influencing ART engagement emphasising the importance of tailored interventions to address the unique challenges faced by both males and females during this critical phase of care.

Site-Species Allometry Equation for Theobroma cacao L. Biomass Estimation in Agroforestry Systems of Cameroon

The accuracy of biomass estimates through mathematical expressions remains essential for the sustainability of the REDD+ process. The objective of this research was to develop allometric models by site species to evaluate the biomass of Theobroma cacao in agroforestry systems in the Central Region of Cameroon. Biomass data were obtained by the destructive method on a sample of 50 trees (5 cm ≤ D ≤ 27 cm). Allometric models were developed using aboveground (AGB), belowground (BGB), and total biomass (TB) as dependent variables and tree dendrometric parameters as independent variables. Nine linear models were adjusted based on the Akaike information criterion (AIC), residual standard error (RSE), coefficient of determination (R2), and various statistical tests including the normality test, heterogeneity, and autocorrelation for the analysis of residuals. The different results show that only the diameter appears to be a good predictor of biomass with an R2 greater than 0.94, 0.85, and 0.95, respectively, for aboveground biomass (M1: ln B = −1.613 + 1.83 × ln (D)), belowground biomass (M1: ln B = −2.611 + 1.65 × ln (D)), and total biomass (M1: ln B = −1.297 + 1.79 × ln (D)). Incorporating crown diameter and height into the models slightly improved the quality of adjusted. Comparison of the models in this study with pantropical equations previously used to estimate Theobroma cacao biomass shows that the models in this study provide a better estimate. The allometric equations developed in this work to estimate the AGB, BGB, and TB of Theobroma cacao can be used under the same environmental conditions to accurately predict the biomass accumulated in agroforestry systems by this species and thus allow the implementation of activities aimed at reducing emissions from deforestation and degradation (REDD+) for the benefit of local communities through the carbon market.

Physical integrity and bioefficacy of used long-lasting insecticidal nets in Makenene, Centre Region of Cameroon.

Long-lasting insecticide nets (LLINs) are the recommended tools against mosquito-borne diseases. However, their physical integrity and bioefficacy in the field could be affected by several factors. This study evaluated the physical integrity and bioefficacy of nets used in Makenene since 2016. Cross-sectional field surveys were carried out after 6 y. A questionnaire was first administered to the heads of households, and then the physical integrity of the LLINs was determined by calculating the proportional hole index (pHI). WHO cone bioassays were conducted to determine the bioefficacy of LLINs currently being used against wild strains of Anopheles gambiae s.l., Culex pipiens s.l., and laboratory-reared pyrethroid-susceptible strain of Anopheles coluzzii (Ngousso). Of the 167 LLINs examined in households, 39.5% were fairly good, 26.4% were acceptable, and 34.1% were damaged. The most torn faces of the nets were the sides used for entering and exiting. None of the 30 LLINs used for WHO cone bioassays was still effective against An. gambiae s.l. and Cx. pipiens s.l. while up to 85.7% of these LLINs were at least effective against the susceptible strain after 24 h, with a significant difference observed when comparing the mortality rates between wild and laboratory-susceptible strain of Anopheles (P-value < 0.01). Anopheles gambiae s.l. were all (100%) identified as An. gambiae s.s. by PCR. The LLINs distributed in Makenene since the 2016 campaign are only effective on susceptible strain and should be replaced for a better control of residual malaria transmission and the nuisance by Culex mosquitoes in the locality.

Evaluation of Non-response to Hepatitis B Vaccines in Individuals Over 15 Years in the Centre Region of Cameroon: A Cross-sectional Study

Background: To investigate the risks factors associated to the non-response of hepatitis B (HB) immunization in participants over the age of 15 years.&#x0D; Methods: From October 2020 to December 2021, data were collected from individuals aged over 15 years who receive at least one dose of vaccine. An algorithm consisted of three (03) tests researching anti-HBs whose detectability threshold was 10 IU/L and anti-HBc.&#x0D; Results: A total of 330 participants were included in this study, among which 158 received three doses of vaccine, of these 83.59% and 6,6% were found positive respectively to anti HBs and anti-HBc. We noted that, age [30 – 40] years [OR= 2.41; CI at 95% (1.24 – 4.80)]; single status [OR=10.80; CI at 95% (1.78 – 114.8)], obesity [OR=2.99; CI at 95% (1.13 – 7.27)], alcohol [OR=10.80; CI at 95% (1.78 – 114.8)]; HEPATITIS vaccine [OR=3.40; CI at 95% (1.24 – 9.10)] were associated with non-response to hepatitis B vaccines.&#x0D; Conclusion: Non-response to hepatitis B vaccination has been influenced by several risk factors that should be considered during the vaccination process.

Prevalence of Malaria and Helminth Infections and Their Link to Knowledge on Preventive Strategies among Asymptomatic Pupils in Rural-urban Cameroon

Aim: The aim of our study was to investigate the prevalence of malaria and helminth infection among asymptomatic primary school children in rural and urban Yaoundé-Cameroon, to assess pupils’ knowledge about malaria and STH infection, and to evaluate the association between this knowledge and actual disease prevalence.&#x0D; Study Design: This study was a cross-sectional and was carried out between October 2019 and December 2019 in six primary schools in the Centre region of Cameroon.&#x0D; Methodology:Pupils in classes 3 to six were recruited for the study. Blood and stool samples were collected and analysed to determine pupils’ disease prevalence. Questionnaires following the KAP and health belief model frameworks were administered to evaluate pupils’ health literacy in malaria and helminths.&#x0D; Results: 457 pupils from rural and urban zones participated in this study. 245 (53.6 %) were female and 212 (46.4 %) were male. The prevalence of anaemia was higher in urban than rural zones. Total malaria prevalence was 17.7%. Malaria parasitaemia prevalence classified according to settings revealed rural zones at 28.6% and urban zones at 13.9%. STH infection showed a total prevalence of 4.8% and 7.9% and 3.7% in rural and urban zones respectively. The prevalence of co-infection was 1.2%. Health-literacy gaps in malaria and helminths were identified. Schooling in rural settings and being older were predictors for having a good knowledge of the diseases. However, having good knowledge was not significantly associated to actual malaria parasitaemia or STH prevalence.&#x0D; Conclusion: Insights from this study are essential for the implementation of successful, sustainable and targeted health-promotion strategies to improve the health and well-being of pupils.

Determinants of Immunovirological Response among Children and Adolescents Living with HIV-1 in the Central Region of Cameroon.

About 90% of new HIV-1 infections in children occur in sub-Saharan Africa, where treatment monitoring remains suboptimal. We sought to ascertain factors associated with immunovirological responses among an ART-experienced paediatric population in Cameroon. A laboratory-based and analytical study was conducted from January 2017 throughout December 2020 wherein plasma viral load (PVL) analyses and CD4 cell counts were performed. Viral suppression (VS) was defined as PVL < 1000 copies/mL and immunological failure (IF) as CD4 < 500 cells/µL for participants ≤5 years and CD4 < 250 cells/µL for those >5 years; p < 0.05 was considered statistically significant. Overall, 272 participants were enrolled (median age: 13 [9-15.5] years; 54% males); median ART duration 7 [3-10] years. Globally, VS was achieved in 54.41%. VS was 56.96% in urban versus 40.48% in rural areas (p = 0.04). IF was 22.43%, with 15.79% among participants ≤5 years and 22.92% among those >5 years (p = 0.66). IF was 20.43% in urban versus 33.33% in rural areas (p = 0.10). Following ART, IF was 25.82% on first-line (non-nucleoside reverse transcriptase inhibitors; NNRTI-based) versus 10.17% on second-line (protease inhibitor-based) regimens (p = 0.01). Interestingly, IF was 7.43% among virally suppressed versus 40.32% among virally unsuppressed participants (p < 0.0001). A low VS indicates major challenges in achieving AIDS' elimination in this paediatric population, especially in rural settings and poor immune statuses. Scaling up NNRTI-sparing regimens alongside close monitoring would ensure optimal therapeutic outcomes.

Geoelectrical and Remote Sensing in the Characterization of the Pan-African Meta-sedimentary Basement Aquifer Systems: A Case Study at Nkoteng-Elap, Central Region of Cameroon

Abstract Nkoteng-Elap, a hamlet in the Central Region of Cameroon (Central Africa), has water issues, particularly with access to drinking water. The current study aims at (1) mapping the fracture networks of aquifers in the conceptual hydrogeological model and (2) delimiting the groundwater potential zones of the study area. A study combining remote sensing and geoelectrical measurements was carried out along profiles sub-perpendicular to the elongation of the geological bodies. Borehole and field geology data were used to validate the results obtained. The findings point to more than 300 linear structures about 0.065-74.89 km long, with two main directions: N80-100°E and N30-50-70°E. According to the Electrical Resistivity Tomography approach, there are three (03) geoelectric levels: conductive (less than 500 Ωm), semi-resistive (6500-12500 Ωm). resistive (more than 12500 Ωm), and resistant intrusive body (2050 Ωm). Existing drillings display three main lithological formations: the alteration zone, the fissured/altered zone, and micaceous quartzite. The correlation between the ERT data and drilling data reveals that the fissured or altered zone observed at 50 m is potentially aquifers. This structure is characterized by medium resistivity values (6500 Ω.m), flow rates of 1 to 3 m3/h for positive boreholes, and by low resistivity values (500 Ω.m), flow rates less than 1 m3/h for negative boreholes. The final map is categorized into five classes: very good, good, moderate, poor, and very poor groundwater potential zones. These results can help find basement aquifers and be useful in the planning and management of groundwater resources in a meta-sedimentary context.

Clinical description of dengue and chikungunya virus infections amongst acute febrile patients in a malaria endemic area of Mfou, the Centre region of Cameroon

This study aims to determine the frequency and clinical manifestations of dengue and chikungunya viral infections in the district hospital of Mfou, Centre region of Cameroon where malaria is endemic. Blood samples were collected from suspected cases and tested for Plasmodium parasites and for the molecular detection of viral RNAs (dengue, zika and chikungunya viruses) using TRIOPLEX qPCR. A total of 108 patients were clinically suspected among which 25 % were male and 50 % were less than 15.5 years old. Of these 14.8 % (16/108) and 2.8 % (3/108) had acute dengue and chikungunya fevers respectively. Co-infection with malaria was reported in 56.3 % (9/16) of Dengue cases and 33.3 % (1/3) of chikungunya cases. Clinical profiling further revealed that nausea and vomiting show a significant difference in dengue infected individuals to those of non-infected individuals (P = 0.027). The presence of dengue fever and chikungunya fever and the absence of specific clinical manifestations highlight the need to strengthen surveillance of acute febrile infections for a better estimation of the burden of arboviruses.

Dynamics of soil organic carbon pools following conversion of savannah to cocoa agroforestry systems in the Centre region of Cameroon

Afforestation of gramineous-woody savannah with cocoa agroforestry systems (cAFS) is a common farmer practice in Cameroon considered as sustainable. Nevertheless, the effects of afforestation of savannah with cAFS on soil organic carbon (SOC) turnover and content, and the factors controlling SOC accumulation and stabilization are unknown. SOC content at 0–10 cm soil layer, and SOC distribution in soil particle size fractions (0–20 μm fraction considered as mineral-associated organic carbon, MAOC; 50–2000 μm considered as particulate organic carbon, POC; and 20–50 μm), were compared in different systems settled on degraded savannah (orthic ferralsols). These systems included annual cropland (≈ 5 years old), cocoa monoculture (≈10 years old), and cAFS (from 20 to 60 years old) including different shade tree species such as Albizia adianthifolia, Canarium schweinfurthii, Dacryodes edulis, Milicia excelsa and Ceiba pentandra. Savannah and nearby secondary forest patches were also included in the design as controls. Soil 13C was analysed to investigate the soil carbon turnover after afforestation (C3 plants) of gramineous savannah (C4 plants).SOC significantly increased in the 0–10 cm depth from 10.6 ± 3.1 g C kg−1 in degraded savannah to 17.9 ± 5.6 g C kg−1 in cAFS reaching similar levels as in nearby secondary forests (16.3 ± 5.8 g C kg−1), while annual cropland and cocoa monoculture presented a non-significant decrease in SOC content. These changes were due to rapid loss of SOC derived from savannah plants (C4) – about 76% within the first 15 years after conversion, and higher gain of SOC derived from C3 plants in cAFS than in the other land uses (e.g. from 3.4 ± 1.5 g C kg−1 in savannah to 17.8 ± 5.7 g C kg−1 in cAFS). This SOC enrichment in cAFS was distributed in POC (64%), MAOC (30%) and the intermediate 20–50 μm soil fraction (6%). The higher annual litter input accumulated on a longer period in cAFS (20 to 60 years) than in cocoa monoculture (10 years) concomitant with the lower litter recalcitrance of associated trees compared to cocoa could explain the higher enrichment of SOC in all fractions in cAFS. The soil pH and exch. Ca2+ differed under the different shade tree species, and were positively correlated to SOC content. The highest contents of soil exch. Ca2+ induced by Ceiba and Milicia in the top 10 cm soil layer could contribute to increase SOC enrichment under those species through soil aggregation and related C stabilization. We found no strong evidence of the effect of soil texture on additional soil carbon accumulation in cAFS, especially for the more stable C pool (MAOC). Our results evidenced that savannah afforestation with cAFS appears as a valuable option for top soil carbon enrichment and should consider tree species associated to cocoa to enhance soil C sequestration, soil quality and cocoa production sustainability.