Douala Town Research Articles

Lost-Phase and Short-Circuit Impacts on Electrical Network Managed by a Dual IPCs 30P15

This work evaluates the impact of short-circuit and the phase-lost in a particular transmission network located in south division in Cameroon (Central Africa). This network is precisely located between two towns called Songloulou and Logbaba (douala Town). The chosen network is modelled in Matlab Simulink software. Further, the network currents and voltages undergo non periodical distortions when short-circuit and phase lost come into play. Those distortions are deleted when dual controllers’ system is introduced and the network is stabilized. It appears that dual IPCs (interphase power controllers) present good results. However, the dual system which is a combination of two IPCs improves the network stability. The investigation of dual IPCs’ system uses the phase shift method.

COVID-19 and Comorbidities in Douala, Cameroon

Aims: Coronavirus disease 2019 (COVID-19) caused by severe acute respiratory syndrome Coronavirus 2 (SARS-CoV-2) still negatively impacting the world. This study aimed at determining the prevalence of COVID-19 and comorbidities, associated factors, and evaluating the impact of these comorbidities on COVID-19 patients.
 Study Design: Cross-sectional hospital-based study.
 Place and Duration of Study: From January to March 2022, the present study was conducted at four health facilities in Douala town (Littoral Region, Cameroon).
 Methodology: Anthropometric, bioimpedance, physiological, blood and nasopharyngeal samples were used for diagnosing COVID-19, hepatitis B virus, diabetes, obesity and hypertension. SARS-CoV-2 genome were detected by retrotranscriptase quantitative polymerase chain reaction. Data were analyzed with StatView v5 and GraphPad v5.03 software, and statistical significance was set at p < 0.05.
 Results: A total of 178 patients, 139 Cameroonian and 39 foreigners, were finally included in the study. Lower COVID-19 vaccination coverage was seen in Cameroonians compared to foreigners (25.2% vs 43.6%, P = .02). No COVID-19 infection cases were found. The overall prevalence of diabetes, hypertension, obesity and HBV was 11.2%, 17.9%, 28.1% and 36.5%, respectively. Nearly 35% of patients were diagnosed with at least two of these comorbidities that significantly impacted on anthropometric, bioimpedance and physiological parameters. The risk of past COVID-infection was increased by 1.06 (95%CI 1.00 – 1.10, P = .03) and 2.81 (95%CI 1.65 – 5.77, P = .04) with one-unit increase in age and BMI, respectively. In contrast, risk of past COVID-19 infection was decreased by 94% (AOR = 0.06, 95%CI 0.01 – 0.76, P = .03) in foreigners compared to Cameroonians.
 Conclusion: This study outlines the importance to manage comorbidities in context of COVID-19 in Cameroon. Further studies should be conducted with more documented investigations about their epidemiology and impact on the natural history of COVID-19 in the country.

Content and Bioavailability of Minerals in Some Cameroonian Foods from Douala: Risks of Micronutrient Deficiencies

Malnutrition and micronutrient deficiencies rates among preschool children and women of childbearing age as the most groups affected, are still rising in Cameroon, despite large food production, which reflected food security over the past three decades. This work aimed at evaluating the nutrient composition of the main family and transitional foods of children in the Douala town of Cameroon for food based malnutrition approach. A food survey by interview using a structured questionnaire, including the recall of the last 24 hours food intakes, food frequency was carried out to over 500 women and caretakers in the city of Douala. Sixteen household dishes were selected from their high consumption frequencies and some traditional complementary foods were analyzed. Moisture and ash were determined by AOAC methods (1980). The following mineral contents: Fe, Zn, Ca, Mg, Mo, Mn, Cu, Cr, Al, Ni, Se, Sn, Cd, Pb, Hg, As were determined by HR-ICP-MS on the mineralized samples and Acid extracts determined to evaluate ‘in vitro’ bioavailability in all the samples. The results were analyzed statistically using the software “STATGRAPHICS” Centurion. For all the foods, the dry matter and ash content (g/100 g MF) ranged from 11.07±2.58 to 42.39±0.06 and from 3.56±0.21 to 8, 88±0.02 respectively. The contents of Ca, Mg, K, P Zn, Cu, Mn, Fe (mg / 100gMS) ranged from 32.01±0.1 to 878.33±128; from 48.67±3.5 to 616.3±150.00; from 22±3 to 142±5; 197±34 to 1346.33±137; 0.49±0.06 to 12.08±0.83; 0.12±0.001 and 0.33±0.02; 0.05±0.001 and 0.8±0.001; and from 1.42±0.55 to 6.61±2.25 respectively. The phytates / zinc ratio ranged from 0.00 to 51.62, thus suspecting a high inhibition of phytates on zinc and other divalent cations. All the foods samples had low mineral content and low bioavailability, which would explain the high prevalence of micronutrient deficiencies and the need to educate mothers and caregivers on dietary diversification in combination with micronutrient supplementation or fortification of infant foods with essential micronutrients where necessary.

Quantitative Ethobotany of Gnetum africanum Welw. (Gnetaceae) in Massoumboum, Littoral Region of Cameroon

Gnetum africanum Welw. is a plant specie of Central and West Africa, a Non Timber Forest Product (NTFP) with high nutritional, medicinal and economic value. In Cameroon, its leaves are recognized by the forestry administration as a special product. Strong demand combined with destructive harvesting techniques has resulted in its rarity in its distribution area. The objective of this work is to characterize the harvesting and trade of G. africanaum, and to assess its abundance (density and structure) in order to appreciate the economic value of the Lehman agroforest system (ALM) based in Massoumboum, a village located at 30 Km of Douala town, the economical capital of Cameroon. An ethnobotanical survey was conducted among harvesters and sellers of G. africanum in the ALM and in adjacent markets. An inventory of G. africanum stems and leaves was carried out at an overall sampling rate of 9.52%. The study revealed that, harvesting of G. africanum is freely done by women, youngers and elders. They start their activity early in the morning and convey their products to markets located in the periphery and inside the city of Douala. The price of the gramme is too high in the periphery than in the city, averaging 0.58 CFA franc. This price is high in the dry season due to the scarcity of other agricultural vegetables. The inventories conducted revealed densities of 6 191 stems/ha and 119 548 leaves/ha, with the high density of leaves obtained in less perturbed plots. The combination of field data (forest inventories) with those obtained in the markets (trade data), what we call « quantitative ethnobotany », allowed us to appreciate the temporal economic value (EV) of the ALM. This EV ranges from 500 000 - 700 000 CFA franc, for an average value of 37 059.9 CFA franc /ha. If well managed, G. africanum can contribute not only to the economy of the women-harvesters, but also to the economy of the ALM. The glaring development challenge of the background of what precedes is the development of non-detriment findings (NDF) for G. africanum in Cameroon. These consist of setting tools which aims to sustain the resource and trade such as the delimitation of Gnetum Allocation Units (GAU), as well as the development and implementation of simple management plans (SMPs).

Less effect of wells physicochemical properties on the antimicrobial susceptibility Pseudomonas aeruginosa isolated in equatorial region of Central Africa

This study aimed at assessing the impact of some wells abiotic factors on the antimicrobial susceptibility of Pseudomonas aeruginosa isolated. A total of 14 well waters of Douala and Yaoundé towns (Cameroon, Central Africa) were chosen. Fifteen antibiotics were used to test antimicrobial susceptibility with the majority belonging to β-lactam, aminoglycoside and quinolone groups. Result showed that in Douala, electrical conductivity of water ranged from 145.38 to 559.69 μS/cm in well, while in Yaoundé, it ranged from 172.5 to 710.2 μS/cm. Dissolved oxygen ranged from 2.5 to 5.5 mg/l and from 3.9 to 5.1 mg/l, respectively, in Douala and Yaoundé. Organic matter varied from 2.3 to 7.2 mg/l and 1.4 to 5.2 mg/l in Douala and Yaoundé, respectively. As for pH, it fluctuated between 5.56 and 6.66 CU and between 5.1 and 7.0, respectively, in Douala and Yaoundé. The sampled waters harbour multi-drug-resistant P. aeruginosa strains. About 20.40% of strains from wells in Yaoundé metropolis expressed resistance to at least 5 antibiotics, whereas from wells in Douala town, up to 33.33% of strains were resistant to at least 8 antibiotics including ticarcillin, ceftazidime and gentamicin. The effect of abiotic factors on the sensitivity to antibiotics was assessed using the multiple regression tests. In both towns, less than 5% in the changes of physicochemical parameters of well waters explained the variance in inhibition diameter values of antibiotics (p ≤ 0.05). The pH significantly impacts on antimicrobial susceptibility. Environmental conditions are less stressful for P. aeruginosa and fairly affect its antimicrobial susceptibility.

Geologic factors controlling groundwater chemistry in the coastal aquifer system of Douala/Cameroon: implication for groundwater system functioning

Douala city, located in the littoral province of Cameroon, receives abundant rainfall quantities due to its geographical position in the Gulf of Guinea and bears considerable surface water and groundwater resources. Due to socioeconomic development and rapid demographic growth in the city and its consequences of unplanned urbanization and improper sanitation system, these water resources are poorly protected and managed. Streams in the Wouri watershed receive large amounts of wastewater discharge, and hundreds of boreholes have been drilled into the aquifer system without any management plan. A detailed hydrodynamic and hydrogeochemistry study in Douala town and its environs was conducted to get a better insight into the groundwater system functioning in order to provide information for the sustainable management and protection of the groundwater resource. Two field campaigns were carried out with 187 samples collected and analyzed for major ions, stable isotopes (18O, 2H), and tritium 3H. The results of the sampling have shown that the weathering of silicate minerals is the dominant geochemical process affecting groundwater chemistry in this system. However, acid rainfall in the humid climate has also caused carbonate mineral dissolution, amorphous silica deposition, and ion exchange reactions to occur in aquifers in the region. The various water types identified were categorized into four major clusters C1 to C4, based on the major ion composition and the local hydrogeological conditions. Environmental isotope data reveal that modern-to-submodern waters occur in the phreatic Quaternary/Mio-Pliocene and Oligocene/Upper Eocene aquifers, respectively. These results corroborate with the conceptual model built where modern groundwater types indicated silicate mineral weathering and calcite dissolution (C1 and C2), whereas submodern groundwater mostly showed silica deposition, ion exchange, and, to a lesser extent, carbonate mineral dissolution (C3 and C4). This improved understanding of the aquifer system functioning is essential to provide a reasonable basis for effective control measures and sustainable water management.

WRF high resolution simulation of an extreme rainfall event over Douala (Cameroon): a case study

An unusual extreme precipitation affected the Douala town of Cameroon during 19–20 June 2015. 24-h accumulated rainfall recorded, exceeded 80 mm/day and led to flash floods, loss of life and severe damage in the area. This study presents the results of a numerical simulation of this event using the Weather Research and Forecasting (WRF) model over three domains with horizontal resolutions of 27, 9 and 3 km. Soundings from Douala International Airport show that this event was associated with the downpours, thunderstorms and high values of Vertical Integral of Water Vapour indicating the intense stormy episode. The values of the Convective Available Potential Energy obtained from the soundings clearly indicate that there was a persistent instability in Douala during this period. In addition the satellite images from infrared channel show that there was the clouds with strong vertical development showing the presence of a stormy area extending on the coasts of Cameroon and Nigeria. Using the WRF model, initialized and bounded by the National Center for Environmental Prediction Global Forecasting System 3 h products, the episode was successfully simulated. The model was able to reproduce the important meteorological features associated with this event, which include good simulation of the Vertical Integral of Water Vapour with the magnitude similar to that obtained from soundings. Relative humidity and low level wind at 850 hPa were also well simulated by the model compared to the ERAI reanalyses data. The surface air was almost saturated in Douala and its surroundings. The prevailing wind was southwest (monsoon) indicating a permanent supply of moisture from the Atlantic Ocean to the continent. The simulated precipitation also compares favorably to the observation and Tropical Rainfall Measuring Mission in term of spatial and total accumulated amount. The WRF model appears to be a tool that might assist forecasters throughout rainy seasons in Central Africa to successfully predict such events.

LBPS 03-13 PROGNOSTIC IMPACT OF EARLY VASCULAR AGING ON MORTALITY IN ACUTE STROKE IN BLACK AFRICAN ANCESTRY

Objective: Evaluate the prognostic impact of PWV and AIx, both biomarkers of EVA on mortality in Cameroonian patients with acute stroke. Design and Method: We prospectively enrolled 138 patients admitted with acute stroke in the two main public teaching hospitals of Douala town, Cameroon (53.9 % females, mean age: 64 ± 13 years). The severity of stroke was assessed on admission with the National Institutes of Health Stroke Scale (NIHSS) score. Heart rate (HR), central blood pressures (BP), AI corrected for HR (AIx) and aortic PWV were measured (SphygmoCor) ≤ one week following stroke onset. The outcome was evaluated at discharge with in-hospital mortality and after discharge with community mortality within 30 days following stroke onset. Results: BP did not differ between died vs. survived patients (p > 0.05). PWV was faster in patients with NIHSS score >14 as compared to those with NIHSS score ≤ 14 on admission: 10.7 ± 2.3 m/s vs 9.7 ± 1.9 m/s, P = 0.012. PWV and AIx were greater in died vs. survived patients: 10.9 ± 2.2 m/s vs 9.7 ± 1.9 m/s P = 0.0022 and 31 ± 12% vs 26 ± 12% P = 0.023, respectively. PWV increased markedly with aging in patients who died as compared to those who survived (P = 0,014). Importantly, aged-adjusted PWV≥10 m/s was strongly associated with early and high mortality rate as compared to participants with PWV 0.05). Multivariate regression analysis revealed that PWV≥ 10 m/s, diabetes mellitus, Glasgow score≤ 8 and NIHSSscore >14, were independent predictors of mortality during acute stroke in our study population. Conclusions: Increased aortic PWV is associated with early and high mortality rate in black Cameroonian patients with acute stroke; independently of other known prognostic factors. EVA may be a potential underlying mechanism explaining severe burden of stroke in black African ancestry.

Formal and Informal Sector Workers Care in Cameroon-Need for Equitable Protection Approach based on Rational Assessment of Risks and Exposures through Carpenter?s Respiratory System Assessment

We explored respiratory symptoms in informal versus formal sector workers, in order to find out if there is a rational reason for selective care towards the latters. Methodology: This was a transversal analytic study comparing spirometry parameters of 35 carpenters from informal sector activity to 35 controls from official sector, all males, matched for body surface area, in Douala town in Cameroon, from March to May 2015. We performed spirometries and clinical examinations. We analyzed data with SPSS V.22. Results: The carpenters and controls showed respectively: average age was 35 vs 34 year; average years spent in function: 13 vs 9 years; systolic blood pressure: 120 vs 115 mmHg (p<0.05); diastolic blood pressure: 79 vs 76 mmHg; on spirometry, forced vital capacity: 92 vs 91; VEMS: 101 vs 96; VEMS/CVF: 108 vs 101; and PEF 91 vs 87. A negative correlation was found between duration on work in years and blood pressure in carpenters (R=- 0.37; p=0.029). A negative correlation was found in carpenters between length of stay at work in years and peak expiratory flow (R=-0.34; p=0.048). Conclusions: The spirometry parameters are more altered in the carpenters compared to controls. There are no abnormalities exclusively present in formal sector workers that could justify their selective care. This study highlights the need for real attention to all workers in terms of preventing their health problems by authorities.

Les plantes à alcaloïdes utilisées par les populations de la ville de Douala (Cameroun)

Objective: An ethnobotanical survey was conducted from January to February 2013 in Douala town relating to the various uses of alkaloids plants species by the people. Methodology and results: Ten districts were surveyed for the census alkaloid plants. These surveys helped conduct semi-structured surveys based on direct questions concerning the therapeutic uses of these plants by the targeted populations. A total of 73 alkaloid plant species were identified of which 21 were herbaceous and 52 woody. Among these species, 30 are indigenous and 43 exotic. They were distributed in 62 genera belonging to 40 families. The supply is provided from farms, secondary forests, gardens, fallows and markets. Solanaceae, Apocynaceae and Rubiaceae are rich in various alkaloids. Leaves, barks and roots are the plant parts mostly used in recipes for the treatment of various diseases. Drugs are mainly administered through the oral root. Secondary metabolites, including alkaloids are unevenly distributed in plants. They are produced at particular stages of development of the flower, fruit, seed or seedling in a specific organ, tissue or cell. Alkaloid plant species are used as major analgesics, antimalarial and to fight against excess uric acid. They are also used as drugs, laxatives, aphrodisiac and as cholinergic or as anticancer agents. They increased heart rate and stimulate the central nervous system with increased vigilance. Conclusion and application of results: All these properties can justify the inclusion of these non timber forest products in forest management programs for their sustainable exploitation.Keywords : Solanaceae; Apocynaceae; Rubiaceae; alkaloids; exploitation

Quality of Packaged Drinking Water Marketed in Douala - Cameroon

Quality and safety of water are very important for the health. The proliferation of conditioned drinking water in urban areas of Cameroon these years raises the problem of quality control. This research was then conducted in Douala town, to determine microbiological and physicochemical qualities of local and imported conditioned drinking water, in order to inform consumers and help them to make better choices. After the survey carried out with the population in Douala town, 32 drinking packaged water in polyethylene bags and bottles were collected and analyzed. The choice was made according to the amount of the persons using this water. The research of the total germs was done by the Plate Count Agar, the coliforms determined by the Eosin Methylen Blue and staphylococcus by the Chapman medium. The hardness, the concentration of calcium and magnesium were determined by complexometric method using tetra acetic diamine ethylen (EDTA). The pH, the turbidity and the conductivity were determined respectively by a pH meter, turbidimeter and a conductimeter. Chlorides and nitrates were measured by UV spectrometric method. According to the results obtained, consumers surveyed choose a type of brand water for economic reasons, 82 % of trademarks investigated had worst sanitary safety. The analytical results demonstrated that 76 % of water produced in Douala are soft (0°F 43°F) and highly mineralized. Water packed in bags harbored numerous species of bacteria including Pseudomonas cepacia, Acinetobacteria, and nonpathogenic Staphylococcus; their densities were respectively, 23x103 ± 3605,55 CFU.100 mL-1, 22x103 ± 1732,05 to 54x103 ± 4582,57 CFU.100 mL-1 and 23x103 ± 2000 CFU.100 mL-1. Conditioned water produced in Douala (in bags) had the worse microbiological quality than the imported water. On the contrary they are softer than imported water.

Medicinal plant knowledge of ethnic groups in Douala town, Cameroon

Plants have traditionally been used as a source of medicine in Cameroon since early times for the control of various ailments afflicting humans and their domestic animals. However, little work has been made in the past to properly document and promote the knowledge. Today medicinal plants and the associated knowledge in the country are threatened due to deforestation, environmental degradation and acculturation. Urgent ethnobotanical studies and subsequent conservation measures are, therefore, required to salvage these resources from further loss. The purpose of the present study was to record and analyse traditional medicinal plant knowledge of ethnic groups in Douala town, Cameroon. Semi-structured interviews were conducted with informants of 75 households selected during transect walks made to houses as well as those identified as knowledgeable and elders to gather data regarding local names of medicinal plants used, parts harvested, ailments treated, remedy preparation methods, administration routes, dosage and side effects. Purposive sampling method was used in the selection of study sites within the study region. The study revealed 94 medicinal plants that belonged to 46 families and 84 genera. The majority of medicinal plants were herbs and leaf was the most frequently used part in the preparation of remedies. Significantly higher average number of medicinal plants was claimed by men, older people and illiterate ones as compared to women, younger people and literate ones, respectively. The majority of the medicinal plants used in the study area were uncultivated ones. The study revealed acculturation as the major threat to the continuation of the traditional medical practice in the study area. Awareness should, therefore, be created among the ethnic groups, especially the young ones, by concerned organizations and individuals regarding the usefulness of the practice.

Inventory and Identification of Plants Used in the Treatment of Diabetes in Douala Town (Cameroon)

Currently, the International Diabetes Federation estimates that 194 million people live with diabetes worldwide are 5.1% of the adult population and this number is estimated at 333 million in 2025. In Africa, there are about 13.6 million people suffering from diabetes. Despite many discoveries made about his treatment, cost of drug prescriptions is very high to justify the continued inaccessibility to medicine for the population living below a dollar daily income per person. The use of medicinal plants is accessible to all strata of society contributing to health for all. This study focuses on the inventory, identification and use of medicinal plants in the treatment of diabetes in Douala town. The ethnobotanical survey conducted in 2009 has enabled the identification of 41 plant species belonging to 36 genera and grouped into 26 families. These plants have led to the establishment of 47 medicinal recipes and some of which have already been cited by other authors. Ten species are common for the treatment of diabetes. These are: Alluim cepa, Aloe vera, Alstonia boonei, Catharanthus roseus, Costus afer, Cassia occidentalis, Ceiba pentandra, Citrus limon, Mangifera indica and Persea americana. The recipes which are more effective to apply every day are: one to two glasses of juice of Brassica oleracea L., a half glass of juice Phaseolus vulgaris L., three glasses of juice made from one to two handfuls of dry beard Zea mays L. boiled in

Water supply, sanitation and health risks in Douala, Cameroon

With a view to contribute to the hygiene condition and improvement in the urban zones of Cameroon, a survey was carried out in March 2007 among 1400 households with respect to the water supply, sanitation and health risks in seven quarters of spontaneous habitat of Douala town. It results from this study that the majority of participants were married (76%). The populations are supplied with of water especially by CAMWATER network (49% of households) and wells (50% of households). The majority of participants evacuate solid waste in public refuse vats (56% of households). Household’s wastewater is especially discharged around the houses (21% of households) and in rivers (20% of households). The companies present in the quarters discharge their wastewater in the drains. 52% of households deposit their excrements in latrines. We noticed in these quarters a prevalence of residences made out of hard materials (43% of households). Cholera (88.5% of households), Diarrhoea (70% of households), Dysenteries (74% of households), Typhoid fever (72% of households), Malaria (32% of households) and skin diseases (76% of households) were the most frequent diseases. These results highlight problems for which, it would firstly be necessary to attack in the research of the improvement strategies for hygiene conditions in the populations of an urban environment. Key words: Environment, sanitation, water, diseases, Douala

Clinical and physiopathological features of cerebral malaria in Douala town, Cameroon

Cerebral malaria (CM) is the most severe neurological complication of infection with Plasmodium falciparum and is a major cause of acute non-traumatic encephalopathy in tropical countries. Insights into the processes leading to cerebral malaria might help to clearly define the patients at risk and identify risk factors for poor prognosis and fatal outcome, for a rapid and adequate intervention. We set out to describe the spectrum of cerebral malaria in our setting, and investigate some factors which may be characteristics of this severe form of the disease, and which may help in improving or accelerating the recognition of cerebral malaria.

Influence of malaria on the serum levels of vitamin A, zinc and calcium of children in Douala-Cameroon

Malaria is an endemic parasitic disease that prevails particularly in warm tropical regions of the world. Micronutrient malnutrition such as vitamin A and iron deficiencies which is a public health problem in Cameroon is usually highly prevalent in malaria endemic areas. Characterizing the relationship between micronutrient status (vitamin A, zinc and calcium) and malaria infection among children in Douala town (Cameroon), serum levels of zinc, calcium and vitamin A, were assayed in a total of 116 Cameroonian children (62 controls and 54 malaria patients infected by Plasmodium falciparum) less than six years old by colorimetric and high pressure liquid chromatography (HPLC) techniques respectively showed a significantly lower vitamin A and calcium concentrations (P < 0.01) among malaria patients (0.8 ± 0.4 µmol/l and 81.3 ± 23.7 mg/l) as compared to the controls (1.1 ± 0.6 µmol/l and 96.3 ± 16.7 mg/ml). Vitamin A, calcium and zinc status were lower in 51.85%, 51.85% and 27.27% of malaria patients respectively. Significant correlations (P<0.01) were observed when the following parameters were coupled: Vitamin A/zinc among infected children (r = 0.01), and vitamin A and zinc among uninfected children (r = 0.415). This study suggests that P. falciparum use vitamin A and calcium of its host for its proper metabolism, leading to a decrease in serum levels of these nutrients.