Knowledge generation via publications on hypertension prevalence in population-based studies conducted in sub-Saharan Africa over 30 years: 1990 - 2019

Hypertension prevalence in sub-Saharan Africa (SSA) is high, is rising and has emerged as the most prevalent cardiovascular disease risk factor. Research is required to provide evidence-based findings to prioritise hypertension prevention and control. This systematic review aims to describe the distribution of and trends in scientific outputs on hypertension prevalence in population-based studies in SSA over the last three decades. Relevant English-language articles documenting hypertension prevalence in population-based studies in SSA, published between 1 January 1990 and 25 April 2019, were identified through a comprehensive electronic search of MEDLINE. Of the 3 795 citations retrieved, 414 fulfilled the inclusion criteria. Scientific outputs increased incrementally per 10-year period: 1990 - 1999: n=32; 2000 - 2009: n=65; and 2010 - 2019: n=317. The greatest number of scientific outputs over the 30-year period originated from South Africa (n=81) and Nigeria (n=74). Increasing scientific outputs on hypertension prevalence in SSA have not translated into optimal hypertension management, which remains inadequate

Growth and yield potential of Echinochloa pyramidalis (Lam.) Hitchc & Chase: A forage plant used in verticalflow constructed wetlands in Cameroon

This work aims at assessing growth and productivity of Echinochloa pyramidalis in the saline and saline-flooded processes of wetland treatment. Growth characteristics such as density, number of dead plants, height and number of new shoots and biomass production of the plant were studied using 24 laboratory-scale units of vertical-flow constructed wetlands fed with faecal sludge supernatant. Plants collected from the surrounding wetlands were subjected to four salinity levels with electrical conductivity of 2, 3, 6 and 9 dS.m-1 under both drained and flooded conditions for a 100 day period. The results revealed that salinity and flooding combined with salinity stresses had similar effect on plant survival, height and density, leading to growth and biomass reduction at the higher salinity level than under natural growth conditions. Despite these stress effects, E. pyramidalis remained healthy with no signs of salt or saline-flooding stress injury but higher biomass production. As E. pyramidalis is a forage plant its high biomass production in the wetland treatment systems shows the potential of wetland systems to create a local economy based on forage production and thus the opportunity to link sanitation stewardship to food production. This may contribute to sustain sanitation infrastructures at the same time as increasing food security, especially in developing countries.Key words: Constructed wetlands, Echinochloa pyramidalis, faecal sludge, flooding, growth, salinity, yield potential

Algal diversity and distribution in Waste Stabilization Ponds treating faecal sludge leachate from drying vegetated beds

Waste Stabilization Ponds (WSP) were tested at pilot scale for the polishing of faecal sludge leachate from planted drying beds in Yaoundé, Cameroon. Water was sampled at three different depths (10, 30, 45 cm) and three different hydraulic retention times (HRT) (4, 7 and 10 days) in two  maturation basins in series for physico-chemical and biological analyses. As a removal mechanism, algae diversity, density and biomass were assessed and correlated to the physical parameters within the ponds. Results showed the presence of nine algal species belonging to three divisions, four classes, six orders, eight families and eight genera. Among these species found in WSPs, Chlamydomonas globosa, Monoraphidium convolutum and pseudanabaena catena were the most abundant whatever the basin, the hydraulic retention time (HRT) and depth. PO4P, NH4N andthe total chlorophyll showed strong correlation with the algal biomass (0.582, 0.731 and 0.895 respectively) at the surface (0-15 cm) followed by TSS, temperature and COD (0.556, 0.509 and 0.533 respectively) at HRT 4days. These correlations were not observed at HRT 7 and 10 days.Keywords: Algal dynamic, Waste Stabilization Pond, faecal sludge leachate, depth, hydraulic retention time

The burden of high blood pressure and related risk factors in urban Sub-Saharan Africa: Evidences from Douala in Cameroon

Objective: To provide the current burden of high blood pressure and related risk factors in urban setting in Cameroon. Methods:We used the WHO STEPS approach for Surveillance of non-communicable diseases and their risk factors to collect data from 2,559 adults aged 15-99 years, residing at Cite des Palmiers in Douala, Cameroon. Results: The level of education was low with up to 60% of participants totalizing less than primary school. Smoking habits were 6 times more frequent in men (

Mass balance of nitrogen and potassium in urban groundwater in Central Africa, Yaounde/Cameroon

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Understanding of research, genetics and genetic research in a rapid ethical assessment in north west Cameroon

BACKGROUND There is limited assessment of whether research participants in low-income settings are afforded a full understanding of the meaning of medical research. There may also be particular issues with the understanding of genetic research. We used a rapid ethical assessment methodology to explore perceptions surrounding the meaning of research, genetics and genetic research in north west Cameroon. METHODS Eleven focus group discussions (including 107 adults) and 72 in-depth interviews were conducted with various stakeholders in two health districts in north west Cameroon between February and April 2012. RESULTS Most participants appreciated the role of research in generating knowledge and identified a difference between research and healthcare but gave varied explanations as to this difference. Most participants' understanding of genetics was limited to concepts of hereditary, with potential benefits limited to the level of the individual or family. Explanations based on supernatural beliefs were identified as a special issue but participants tended not to identify any other special risks with genetic research. CONCLUSION We demonstrated a variable level of understanding of research, genetics and genetic research, with implications for those carrying out genetic research in this and other low resource settings. Our study highlights the utility of rapid ethical assessment prior to complex or sensitive research

The economic potential of Echinochloa pyramidalis (Lam.) Hitchc & Chase forage plant used in liquid waste treatment in Cameroon: Opportunity to link sanitation to food security

Cameroon, like other developing countries, faces major problems in the urban centres such as high rate of population increase, food and ruminant feed shortages as well as inadequate access to sanitation. However, Echinochloa pyramidalis, well-known forage adapted to the drying vegetated beds for wastewater and faecal sludge treatments with similar characteristics as Typha sp., Phragmites sp., might be used in the dual purpose as animal feed and as support material in sanitation treatment. This study aimed at linking sanitation technology to forage production. A socio-economic survey conducted in Douala, Yaoundé and Garoua to evaluate the economic potential of E. pyramidalis showed the daily quantities of marketed forage between 5 and 8-tons of fresh weight (FW) respectively during dry and rainy season. The forage price varies with season and species from USD 0.1–0.2 to USD 0.2–0.3/kg FW with daily income of USD 800–1’600 and USD 500–1’500 respectively to rainy and dry season. While comparable to most tropical forages, the nutritional values of E. pyramidalis after 45 and 100 days of wetland treatment were only affected by the advancing maturity. Thus, E. pyramidalis can be easily grown in wetland systems and sold for animal feeding in the local market.Keywords: Echinochloa pyramidalis, economic potential, forage production, nutritional values, sanitation technology, vertical-flow constructed wetland

A new species in the major malaria vector complex sheds light on reticulated species evolution

Complexes of closely related species provide key insights into the rapid and independent evolution of adaptive traits. Here, we described and studied Anopheles fontenillei sp.n., a new species in the Anopheles gambiae complex that we 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. Particularly, we detected recent introgression, with Anopheles gambiae and Anopheles coluzzii, of genes directly involved in vectorial capacity. Moreover, genome analysis of the new species allowed us to clarify the evolutionary history of the 3La inversion. Overall, An. fontenillei sp.n. analysis improved our understanding of the relationship between species within the An. gambiae complex, and provided insight into the evolution of vectorial capacity traits that are relevant for the successful control of malaria in Africa

Anemia in patients on chronic hemodialysis in Cameroon: prevalence, characteristics and management in low resources setting

Background: Anemia is a common complication of chronic kidney disease. We investigated the prevalence, characteristics and management of anemia in patients on chronic hemodialysis and assessed the response to blood-transfusion based management in Cameroon.Methods: This was a cohort study of five months’ duration (August-December 2008) conducted at the Yaoundé General Hospital’s hemodialysis center, involving 95 patients (67 men, 70.5%) on chronic hemodialysis by a native arterio-venous fistula. A monthly evaluation included full blood counts, number of pints of red cell concentrates transfused, and vital status.Results: At baseline, 75 (79%) patients had anemia which was microcytic and hypochromic in 32 (43%). Anemia was corrected in 67 (70.5%) patients using blood transfusion only, while 28 (29.5%) patients were receiving erythropoietin (11 regularly, 39%). Only 77.2% of 342 pints (median 3.0, range 0-17 per patients) of red cell concentrates prescribed were effectively received during the follow-up at an unacceptably high cost to patients and families. Mean hemoglobin and mean corpuscular hemoglobin levels remained stable during follow-up, while mean corpuscular volume increased. Erythropoietin treatment was the main determinant of favorable trajectories of hematological markers.Conclusions: Patients on chronic hemodialysis have predominantly microcytic hypochromic anemia, with limited capacity for correction using blood transfusion.Key words: Anemia; Blood transfusion; End stage renal disease; Hemodialysis; Sub-Saharan Afric