STRUCTURE GENETIQUE DES POPULATIONS D’ANOPHELES NILI S.S VECTEUR DU PALUDISME EN MILIEU RURAL ET PERIURBAIN DE COTE D’IVOIRE

In Côte d’Ivoire, the Anopheles nili s.s species plays an important role in malaria transmission. However, the transmission of malaria by the populations of An. nili s.s in different regions of Côte d’Ivoire exhibits heterogeneous patterns. The study was initiated to find out whether the diversity of malaria vectorial transmission with An. nili s.s from different regions was linked to a heterogeneity of these species populations in Côte d’Ivoire. To better conduct this study, 134 individuals of An. nili s.s mosquitoes were obtained from a human landing collection and a study on the structure of the populations was carried out by isoenzyme analysis of 7 loci (IDH1, IDH2, PGI, GOT, ME, MDH, PGM). The study sites include Ganse (rural, shrubby savannah), Gbatta, Gouliako (rural, forest zone), Nambekaha (rural, Sudanian savannah), and Kpehiri (peri-urban, forest zone). The An. nilis.s populations in Côte d’Ivoire have on average 1.5 to2.5 alleles per locu and were at Hardy–Weinberg equilibrium. The comparison of the populations shows over the 7 loci, no significant difference between the pairs of populations. The comparison of the An. nili s.s populations from Kpehiri to that of Ganse shows over all loci a significant difference (Fst = 0,1086 ; P= 0,0147). The structure of the An. nili s.s populations in Côte d’Ivoire is not linked to the distribution of the large vegetal groups (forest, shrubby savannah Sudanian savannah). Yet, there is a difference between the Ganse population, in a rural zone, located close to the Comoe National Park and that of Kpehiri in the peri-urban area

Anemia in type 2 diabetic patients and correlation with kidney function in a tertiary care sub-Saharan African hospital: a cross-sectional study

BackgroundAnemia is common in diabetic patients and increases morbidity and mortality, but its burden has been less well characterized in sub-Saharan Africans. We determined the prevalence of anemia and investigated the related factors, with a particular focus on the role of declining renal function, in type 2 diabetic patients attending a tertiary health care institution in Cameroon.MethodsHemoglobin (Hb) levels were measured in a consecutive sample of patients with type 2 diabetes, who reported for annual review at the outpatient section of the Douala General Hospital in 2013. Patients were classified as anemic according to the World Health Organisation criteria (Hb < 12g/dl for females and Hb < 13g/dl for males). Estimated glomerular filtration rate (eGFR) was calculated using the abbreviated Modification of Diet in Renal Disease Study Group formula. Determinants of Hb concentration and anemia were investigated using multivariable logistic regressions.ResultsA total of 636 patients were examined including 263 (prevalence rate 41.4%) who had anemia. The prevalence of anemia increased significantly with deteriorating kidney function, although up to 31.9% of patients with normal kidney function had anemia. Compared with their non-anemic counterparts, anemic diabetic patients were older, had longer duration of diabetes, lower eGFR, higher prevalence of proteinuria and diabetic retinopathy (all p < 0.05). In multivariable logistic regressions, eGFR (p = 0.001) and presence of retinopathy (p = 0.023) were the independent determinants of prevalent anemia.ConclusionsThe prevalence of anemia is high in type 2 diabetic patients attending referral institutions in Cameroon, including among those without chronic kidney disease. Routine screening for anemia in all diabetic patients may aid early identification and correction as appropriate

Co-composting of sewage sludge and Echinochloa pyramidalis (Lam.) Hitchc. & Chase plant material from a constructed wetland system treating domestic wastewater in Cameroon

Trials were conducted at the Cité-Verte domestic wastewater treatment station (Yaoundé-Cameroon) in order to assess the effect of three sewage sludge: Macrophyte ratios on the co-composting process and compost quality. The ratios were T1: 25 kg of plant material (Echinochloa pyramidalis) and 75 kg sludge; T2: 50 kg of plant material and 50 kg sludge, and T3: 75 kg of plant material and 25 kg of sludge. The assessment parameters of the co-composting process included the daily evolution of temperature, the pH and water content for each month. The quality of the mature compost obtained was analysed based on their C/N ratio, Ca, Mg, P, K, trace elements and helminth eggs content. During cocomposting, maximum temperatures ranged from 45.3 ± 4.7°C (T1) to 70.77 ± 2.76°C (T3). Mature cocompost was obtained after 3 months (T1), 4 months (T2) and 5 months (T3). Mean pH and C/N ratio of co-composts respectively ranged from 7.26 to 7.62 and from 10 to 15. In mature compost, the average values of organic matter, N and P respectively were 3323 ± 405 mg/kg, 165 ± 32 mg/kg and 36 ± 5 mg/kg for T1; 2945 ± 128 mg/kg, 152 ± 30 mg/kg and 27 ± 6 mg/kg for T2; and 228 ± 103 mg/kg, 105 ± 48 mg/kg and 7 ± 1 mg/kg for T3. K content was 1 mg/kg in all three co-composts. Heavy metals were found at trace levels. Helminth eggs concentration in compost was 0.2 ± 0.03 egg/g (T1), 0.1 ± 0.02 egg/g (T2) and 0.007 ± 0.01 egg/g (T3). All these co-composts did not present a significant hygienic risk with regards to WHO guidelines (2006) for safe reuse of faecal matter or faecal sewage in agriculture (less than 1 egg/g TS). For a given amount of plant harvested, it was concluded that the quickest way to produce a compost safe of parasites will be to mix them with 3/4 of sludge from the digestion tank.Key words: Co-composting, Cameroon, compost quality, Echinochloa pyramidalis, hygienic risk, sewage sludge

Comparison of different blood pressure indices for the prediction of prevalent diabetic nephropathy in a sub-Saharan African population with type 2 diabetes

Background: The association between blood pressure (BP) and diabetic kidney diseases in Africans has been less well investigated. We assessed and compared the strength of the association and discriminatory capability of systolic (SBP), diastolic (DBP) BP, pulse pressure (PP) and mean arterial blood pressure (MAP) for nephropathy risk in sub-Saharan Africans with type 2 diabetes. Methods: Participants were 420 consecutive individuals (49% men) with type 2 diabetes receiving chronic care in two main referral centres in the two major cities of Cameroon. Logistic regression models were used to compute the odd ratio (OR) and 95% confidence interval (95% CI) for a standard deviation (SD) higher level of SBP (25 mmHg), DBP (13), PP (18) and MAP (16) with nephropathy risk. Discrimination was assessed and compared with c-statistics and relative integrated discrimination improvement (RIDI, %). Results: The adjusted OR (95% CI) for nephropathy with each SD higher BP variable were: 1.45 (1.15-1.84) for SBP, 1.33 (1.06-1.66) for DBP, 1.35 (1.06-1.71) for PP and 1.42 (1.13-1.78) for MAP. C-statistic comparison showed no difference in discrimination of models with each of the BP variables (p-values B 0.69 for c-statistics comparison). However, RIDI statistic always showed and enhancement in models discrimination when other BP variables were replaced with SBP, although such an enhancement was marginal for MAP. Using BP combination modestly improved models? discrimination. Conclusion: SBP was the best predictor of prevalent nephropathy in this population, while DBP was the less effective. This may have implication for kidney disease risk stratification and protection

Epidemiology of histologically proven Glomerulonephritis in Africa: A systematic review and meta-analysis

Background and aim: Glomerulonephritis (GN) is a leading cause of end-stage renal disease (ESRD) in Africa. Data on epidemiology and outcomes of glomerular diseases from Africa is still limited. We conducted a systematic review on the epidemiology of histologically proven glomerular diseases in Africa between 1980 and 2014. Materials and methods We searched literature using PubMed, AfricaWide, the Cumulative Index to Nursing and Allied Health Literature on EBSCO Host, Scopus, African Journals online databases, and the African Index Medicus, for relevant studies. The review was conducted using standard methods and frameworks using only biopsy-confirmed data. RESULTS: Twenty four (24) studies comprising 12,093 reported biopsies from 13 countries were included in this analysis. The median number of biopsies per study was 127.0 (50-4436), most of the studies (70.0%) originated from North Africa and the number of performed kidney biopsies varied from 5.2 to 617 biopsies/year. Nephrotic syndrome was the commonest indication of renal biopsy. The frequency of reported primary pathologic patterns included, minimal change disease (MCD); 16.5% (95%CI: 11.2-22.6), focal segmental glomerulosclerosis (FSGS); 15.9% (11.3-21.1), mesangiocapillary GN (MCGN); 11.8% (9.2-14.6), crescentic GN; 2.0% (0.9-3.5) and IgA nephropathy 2.8% (1.3-4.9). Glomerular diseases related to hepatitis B and systemic lupus erythematosus had the highest prevalence among assessed secondary diseases: 8.4% (2.0-18.4) and 7.7% (4.5-11.7) respectively. There was no evidence of publication bias and regional differences were seen mostly for secondary GNs. CONCLUSIONS: Glomerular diseases remain poorly characterized in sub-Saharan Africa due to declining renal biopsy rates and consequent paucity of data on pathologic patterns of key renal diseases. Development of renal biopsy registries in Africa is likely to enable adequate characterization of the prevalence and patterns of glomerular diseases; this could have a positive impact on chronic kidney disease evaluation and treatment in the African continent since most glomerulopathies are amenable to treatment

Validation of the Friedewald formula for the estimation of low density lipoprotein cholesterol in a sub-Saharan African population.

BACKGROUND: Low density lipoprotein cholesterol (LDL-C) levels are used to estimate cardiovascular disease (CVD) risk and to guide prescriptions. To circumvent the challenges of direct LDL-C measurement, guidelines recommend the use of Friedewald formula derived LDL-C levels. Despite reported limitations of this formula, its validity in sub-Saharan Africans has not been adequately investigated. OBJECTIVE: To assess the validity of the Friedewald formula derived against directly (homogeneous) measured LDL-C in adult Cameroonians. METHODS: We reviewed the fasting lipid profiles of 2500 patients, performed between March 2012 and January 2016 using enzymatic colorimetric method (reference), at the Douala General Hospital laboratory. The Friedewald formula was used to calculate LDL-C from total cholesterol, high density lipoprotein cholesterol and triglyceride levels. Calculated LDL-C values were compared to the reference values, and clinical significance of differences between the two methods was assessed using total error allowable (TEa). RESULTS: The difference between means of calculated and the reference LDL-C values was neither statistically nor clinically significant (3.33±1.51 vs. 3.33±1.25mmol/l; p=0.704). The calculated LDL-C correlated positively with the measured LDL-C value (r=0.749) and both methods showed a good agreement on Bland-Altman plot. Conversely, there was only moderate agreement (kappa=0.478, 95% CI: 0.455-0.502) between the two values in the stratification of cardiovascular risk according to the National Cholesterol Education Program/Adult Treatment Panel III. Consequently, 40.6% of the participants were misclassified. CONCLUSION: Friedewald formula is technically accurate but has a modest clinical accuracy which can translate into a substantial misclassification of patients' cardiovascular risk and subsequent inappropriate therapeutic decisions

A cross-sectional study of malaria transmission in suggests the existence of a potential bridge vector susceptible of ensuring the transfer of simian malaria parasites to humans

Introduction: Despite all the efforts made to control or even eliminate malaria, the disease continues to claim the highest number of victims of vector-borne pathogens in the world and Sub-Saharan countries bear the heaviest burden. The lack of knowledge of the role of various protagonists involved in the transmission of this parasitic disease, such as mosquito vectors and the plasmodial species they transmit as well as the host species they infect in a locality, constitutes one of the main causes of the persistence of malaria. In Gabon, in several areas, entomological data on malaria transmission remain poorly known. Thus, this study aimed to determine the diversity of Anopheles involved in malaria transmission in different environments of the province of Nyanga in southwest Gabon.Methods: For this, an entomological study was carried out in the four main localities of the province of Nyanga to provide answers to these shortcomings. Mosquitoes were collected over several nights using the human landing catch method. The identification of Anopheles and malaria parasites circulating in the different sites was achieved by combining morphological and molecular analysis tools.Results: A total of five hundred and ninety-one (591) mosquitoes belonging to the Culicidae family were collected. From this collection of adult mosquitoes, nine species of Anopheles mosquitoes notably species of the Anopheles nili complex (53.46%) followed by those of Anopheles gambiae complex (22.01%), Anopheles funestus group (18.24%), Anopheles moucheti complex (5.66%) and Anopheles hancocki (0.63%). Approximately 18 percent of these Anopheles species were infected with Plasmodium spp. Anopheles funestus, known to be involved in malaria transmission to humans, and An. moucheti-like, recently discovered in Gabon, and whose status in Plasmodium transmission is not yet elucidated, were found to be infected with great ape Plasmodium.Discussion: Our results raise the question of the potential switch of simian malaria parasites to humans. If these observations are confirmed in the future, and the infective capacity of the bridge vectors is demonstrated, this new situation could ultimately constitute an obstacle to progress in the fight against malaria

Antibacterial and antifungal activity of the essential oil extracted by hydro-distillation from Artemesia Annua grown in

Abstract: This study was carried out to assess the in vitro antimicrobial potential of the Essential Oil (EO) extracted by hydro-distillation from the variety of A. annua grown in West Cameroon. This evaluation was conducted by testing the microbial growth inhibition through agar diffusion, minimal inhibitory and minimal lethal concentrations. Tested microorganisms included bacteria isolates belonging to the following categories: Staphylococcus aureus, Escherichia coli, Salmonella Enteritidis, Shigella flexneri, Proteus mirabilis, Pseudomonas aeruginosa, Klebsiella pneumoniae and Vibrio cholerae. This activity was also tested on a dimorphic fungal species, Candida albicans. Data analysis revealed that the EO possessed an intrinsic antimicrobial activity that was potentiated by the solvent (DMSO). Inhibition zone diameters varied from 6 (Pseudomonas aeruginosa and Shigella flexneri) to 45 mm (Vibrio cholerae). It was also observed that Vibrio cholerae was susceptible to the lowest concentration of the essential oil used (0.3 mg/mL), while Pseudomonas aeruginosa was shown to tolerate the highest (80 mg/mL). Also, the minimal inhibitory and lethal concentrations were equal (MLC/MIC = 1), implying the absolute lethal property of the oil. This lethal potential on fungi, Gram-negative and Gram-positive bacteria makes of this plant an appropriate candidate for new conventional antimicrobial drug production and infectious disease prevention. Well exploited, it might be used to control the current epidemics of Vibrio cholerae-associated cholera in Cameroon. Additional studies should also be conducted to lay down reliable basis for comprehensive test interpretations that take into account correlations between these in vitro test results and the ones that would be obtained with conventional antimicrobials

An effective organic waste recycling through vermicomposting technology for sustainable agriculture in tropics

peer reviewedPurpose The management of household wastes has been a real challenge for the capital city of Cameroon for some years now. In order to adopt ecological and sustainable strategies for better management of organic fraction of solid wastes, the present work was aimed to propose a sustainable alternative for the recycling of household organic waste through a vermicomposting process. Method A vermicomposting of household organic waste was carried out during 46 days, preceded by 23 days of pre-composting. Then, three treatments were established by mixing epigeic earthworms with different proportion of pre-composted waste. Maturation parameters such as pH, electrical conductivity (EC), C/N ratio, ammonium (N-NH4+ ) and total organic matter (TOM) were monitored about four weeks. The agronomic quality of the vermicompost was also determined at the end. Results During pre-composting, the temperature reached a maximum of 54.3±5.4°C suitable for the elimination of potential pathogen. The pH varied between 9.44 and 8.53 leading towards neutrality at the end of the vermi-composting process. The obtained mean values of C/N ratio and the TOM were respectively 11.04-11.68 and 25.82-27.19% in line with the AFNOR (NFU 44-051) guideline. The obtained vermicompost revealed high levels of nutrients such as N, P, K, Ca and Mg. The phytotoxicity test on lettuce showed germination rates above 50%, revealing the non-toxic nature of the vermicompost produced. Conclusion The vermicompost were rich in nutrients and exhibited the non-phytotoxicity. Thus, vermicomposting can be applied in the context of Cameroon to transform organic waste into organic fertiliser suitable for sustainable agriculture

A new species in the Anopheles gambiae complex reveals new evolutionary relationships between vector and non-vector species

Complexes of closely related species provide key insights about the rapid and independent evolution of adaptive traits. Here, we described and studied a presumably new species in the Anopheles gambiae complex, Anopheles fontenillei, recently discovered in the forested areas of Gabon, Central Africa. Our analysis placed the new taxon in the phylogenetic tree of the An. gambiae complex, revealing important introgression events with other members of the complex. In particular, we detected recent introgression with An. gambiae and An. coluzzii of genes directly involved in vectorial capacity. Moreover, genome analysis of the new species also allowed us to resolve the evolutionary history of inversion 3La. Overall, Anopheles fontenillei has implemented our understanding about the relationship of species within the gambiae complex and provides insight into the evolution of vectorial capacity traits, relevant for the successful control of malaria in Africa.Funding was provided by the “Institut de Recherche pour le Developpément”, the “Agence Universitaire de la Francophonie” (grant: OKANDA), the “Centre National de la Recherche Scientifique” (CNRS) and the “Consejo Superior de Investigaciones Cientificas” (CSIC) (grant PICS ANCESTRAL to DA and JG), the “ANR” (grant ANR--18-CE35-0002-01-WILDING to DA), and the “Ministerio de Ciencia, Innovación y Universidades/AEI” (grant BFU2017-82937-P to JG).N