WorldWideScience

Sample records for cameroon west africa

  1. Common challenges in gum arabic production and commercialization in West Africa: a comparative study of Cameroon, Niger and Senegal

    NARCIS (Netherlands)

    Mujawamariya, G.; Madi, O.P.; Zoubeirou, A.M.; Sene, A.; Maisharou, A.; Haese, D' M.F.C.

    2013-01-01

    As gum arabic is widely used in food and non-food industries, demand is high all over the world. Still, smaller production countries in West Africa such as Cameroon, Niger and Senegal seem to have so many difficulties producing and commercializing gum arabic that their market shares have declined si

  2. Fallow practices in West Africa: A comparative importance of phenomenon in Cameroon and Nigeria

    OpenAIRE

    Nkamleu, Guy Blaise

    1999-01-01

    There is a clear need to understand the characteristics of fallow in order to seek appropriate alternatives. From a simultaneous study done in Cameroon and Nigeria, we assessed the specificity of fallow techniques in both countries and discovered that fallow practices remain important in traditional farming systems. Fallow is specifically applied in food crops and forest fields. There are less common in perennial fields and homegardens. Fallow practices remain the major land use technologies ...

  3. Structure of the Crust beneath Cameroon, West Africa, from the Joint Inversion of Rayleigh Wave Group Velocities and Receiver Functions

    Energy Technology Data Exchange (ETDEWEB)

    Tokam, A K; Tabod, C T; Nyblade, A A; Julia, J; Wiens, D A; Pasyanos, M E

    2010-02-18

    The Cameroon Volcanic Line (CVL) is a major geologic feature that cuts across Cameroon from the south west to the north east. It is a unique volcanic lineament which has both an oceanic and a continental sector and consists of a chain of Tertiary to Recent, generally alkaline volcanoes stretching from the Atlantic island of Pagalu to the interior of the African continent. The oceanic sector includes the islands of Bioko (formerly Fernando Po) and Sao Tome and Principe while the continental sector includes the Etinde, Cameroon, Manengouba, Bamboutos, Oku and Mandara mountains, as well as the Adamawa and Biu Plateaus. In addition to the CVL, three other major tectonic features characterize the region: the Benue Trough located northwest of the CVL, the Central African Shear Zone (CASZ), trending N70 degrees E, roughly parallel to the CVL, and the Congo Craton in southern Cameroon. The origin of the CVL is still the subject of considerable debate, with both plume and non-plume models invoked by many authors (e.g., Deruelle et al., 2007; Ngako et al, 2006; Ritsema and Allen, 2003; Burke, 2001; Ebinger and Sleep, 1998; Lee et al, 1994; Dorbath et al., 1986; Fairhead and Binks, 1991; King and Ritsema, 2000; Reusch et al., 2010). Crustal structure beneath Cameroon has been investigated previously using active (Stuart et al, 1985) and passive (Dorbath et al., 1986; Tabod, 1991; Tabod et al, 1992; Plomerova et al, 1993) source seismic data, revealing a crust about 33 km thick at the south-western end of the continental portion of the CVL (Tabod, 1991) and the Adamawa Plateau, and thinner crust (23 km thick) beneath the Garoua Rift in the north (Stuart et al, 1985) (Figure 1). Estimates of crustal thickness obtained using gravity data show similar variations between the Garoua rift, Adamawa Plateau, and southern part of the CVL (Poudjom et al., 1995; Nnange et al., 2000). In this study, we investigate further crustal structure beneath the CVL and the adjacent regions in

  4. Neotectonic earth movements related to the 1999 eruption of Cameroon Mountain, West Africa

    Institute of Scientific and Technical Information of China (English)

    C. E. Suh; S. N. Ayonghe; E. S. Njumbe

    2001-01-01

    @@ The 1999 eruption of Cameroon Mountain was restricted to two sites and controlled by fissures subparallel to one another. Brittle failure, vertical displacement, horizontal displacement and ground deflation are the main types of ground deformation around these sites. The eruptive vents at both sites have a NE-SW trend parallel to the principal eruptive fissures and brittle discontinuities in rock bodies in this vicinity. SH (greatest horizontal stress) is inferred to have a SW-NE trend parallel to the direction of vent migration and fracture propagation.

  5. West and Central Africa.

    Science.gov (United States)

    Lydie, N; Robinson, N J

    1998-01-01

    This article reviews scientific and other literature during the 1990s that links migration and mobility with the spread of sexually transmitted diseases (STDs), including HIV/AIDS. The focus is on key population groups linked to the spread of HIV and STDs in West and Central Africa: migrant laborers, truck drivers, itinerant traders, commercial sex workers (CSWs), and refugees. Countries with high emigration and immigration tend to have high levels of HIV infection, with the exception of Senegal. The main destination of immigrants are Senegal, Nigeria, and Cote d'Ivoire in West Africa and Cameroon, Congo, Gabon, and Congo in Central Africa. The risk of infection and the spread of HIV is variable among migrants. There is little in the literature that substantiates hypotheses about the strong association between migration and HIV-positive status. Information is needed on the duration, frequency of return visits, living conditions, sexual activities with multiple partners, and information before departure, along the routes, at final destination, and at the time of returns. Action-based research in five West African countries (Burkina Faso, Cote d'Ivoire, Mali, Niger, and Senegal) should produce results in late 1998. Comparable studies in Central Africa are unknown. Regional studies should be complemented by local studies. Prevention would benefit from studies on the relative size of these five population groups by geographic location.

  6. Does malaria epidemiology project Cameroon as `Africa in miniature'?

    Indian Academy of Sciences (India)

    Huguette Gaelle Ngassa Mbenda; Gauri Awasthi; Poonam K Singh; Inocent Gouado; Aparup Das

    2014-09-01

    Cameroon, a west-central African country with a ∼20 million population, is commonly regarded as ‘Africa in miniature’ due to the extensive biological and cultural diversities of whole Africa being present in a single-country setting. This country is inhabited by ancestral human lineages in unique eco-climatic conditions and diverse topography. Over 90% Cameroonians are at risk of malaria infection, and ∼41% have at least one episode of malaria each year. Historically, the rate of malaria infection in Cameroon has fluctuated over the years; the number of cases was about 2 million in 2010 and 2011. The Cameroonian malaria control programme faces an uphill task due to high prevalence of multidrug-resistant parasites and insecticide-resistant malaria vectors. Above all, continued human migration from the rural to urban areas as well as population exchange with adjoining countries, high rate of ecological instabilities caused by deforestation, poor housing, lack of proper sanitation and drainage system might have resulted in the recent increase in incidences of malaria and other vector-borne diseases in Cameroon. The available data on eco-environmental variability and intricate malaria epidemiology in Cameroon reflect the situation in the whole of Africa, and warrant the need for in-depth study by using modern surveillance tools for meaningful basic understanding of the malaria triangle (host-parasite-vector-environment).

  7. West Africa

    Science.gov (United States)

    2002-01-01

    With its vast expanses of sand, framed by mountain ranges and exposed rock, northwestern Africa makes a pretty picture when viewed from above. This image was acquired by the Moderate-resolution Imaging Spectroradiometer (MODIS), flying aboard NASA's Terra spacecraft. The Canary Islands can be seen on the left side of the image just off Africa's Atlantic shore. The light brown expanse running through the northern two thirds of the image is the Sahara Desert. The desert runs up against the dark brown Haut Atlas mountain range of Morocco in the northwest, the Atlantic Ocean to the west and the semi-arid (light brown pixels) Sahelian region in the South. The Sahara, however, isn't staying put. Since the 1960s, the desert has been expanding into the Sahelian region at a rate of up to 6 kilometers per year. In the 1980s this desert expansion, combined with over cultivation of the Sahel, caused a major famine across west Africa. Over the summer months, strong winds pick up sands from the Sahara and blow them across the Atlantic as far west as North America, causing air pollution in Miami and damaging coral reefs in the Bahamas and the Florida Keys. The white outlines on the map represent country borders. Starting at the top-most portion of the map and working clockwise, the countries shown are Morocco, Western Sahara, Mauritania, Senegal, Mali, Burkina Fasso, Nigeria, Mali (again), and Algeria. Image by Reto Stockli, Robert Simmon, and Brian Montgomery, NASA Earth Observatory, based on data from MODIS

  8. Epidemiology of HPV in HIV-Positive and HIV-Negative Fertile Women in Cameroon, West Africa

    Directory of Open Access Journals (Sweden)

    Andrew J. Desruisseau

    2009-01-01

    Full Text Available Background. HPV types vary by country and HIV status. There are no data on the prevalent HPV genotypes from Cameroon. Methods. We conducted a cross-sectional, observational study on 65 Cameroonian women. Samples were sent for HPV genotyping and Thin Prep analyses. Results. 41 out of 61 samples tested (67.2% had HPV subtypes detected. The most common high risk types encountered were: 45 (24.6% and 58 (21.5%. HIV-positive women were more likely to test positive for any HPV (P=.014, have more than one HPV subtype (P=.003, and to test positive for the high risk subtypes (P=.007. Of those with high risk HPV, HIV-positive women were more likely to have Thin Prep abnormalities than HIV-negative women (P=.013. Conclusions. Oncogenic HPV subtypes 45 and 58 were more prevalent than those subtypes carried in the quadrivalent vaccine. Further studies are needed to assess whether the current vaccine will be effective in this region.

  9. Epidemiology of HPV in HIV-Positive and HIV-Negative Fertile Women in Cameroon, West Africa

    Science.gov (United States)

    Desruisseau, Andrew J.; Schmidt-Grimminger, Delf; Welty, Edith

    2009-01-01

    Background. HPV types vary by country and HIV status. There are no data on the prevalent HPV genotypes from Cameroon. Methods. We conducted a cross-sectional, observational study on 65 Cameroonian women. Samples were sent for HPV genotyping and Thin Prep analyses. Results. 41 out of 61 samples tested (67.2%) had HPV subtypes detected. The most common high risk types encountered were: 45 (24.6%) and 58 (21.5%). HIV-positive women were more likely to test positive for any HPV (P = .014), have more than one HPV subtype (P = .003), and to test positive for the high risk subtypes (P = .007). Of those with high risk HPV, HIV-positive women were more likely to have Thin Prep abnormalities than HIV-negative women (P = .013). Conclusions. Oncogenic HPV subtypes 45 and 58 were more prevalent than those subtypes carried in the quadrivalent vaccine. Further studies are needed to assess whether the current vaccine will be effective in this region. PMID:20169094

  10. Dracaena in West Africa

    NARCIS (Netherlands)

    Bos, J.J.

    1984-01-01

    This taxonomic revision of the genus Dracaena L. (Liliaceae) in West Africa is another contribution towards a monograph on this group.Short general chapters contain historical, phytogeographical, morphological and phylogenetic observations. The taxonomic treatment contains a revised genus descriptio

  11. Drought in West Africa

    Science.gov (United States)

    2007-01-01

    Drought settled over West Africa's Ivory Coast region when wet season rains came late in 2007. Instead of beginning in February, the rainy season didn't start until March, and steady rains didn't start until late March, said the Famine Early Warning System Network. Though the rain had started to alleviate the drought, vegetation was still depressed in parts of Cote d'Ivoire (Ivory Coast) between March 22 and April 6, 2007, when the Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA's Terra satellite captured the data used to make this image. The image shows current vegetation conditions compared to average conditions recorded since 2000. Areas where plants are growing more slowly or more sparsely than average are brown, while areas where vegetation is denser than average are green. The brown tint that dominates the image indicates that plants through most of the country are more sparse than normal. Among the crops affected by the lack of rain was West Africa's cocoa crop. About 70 percent of the world's cocoa comes from West Africa, and Cote d'Ivoire is a top grower, said Reuters. Cocoa prices climbed as the crop fell short. Farmers called the drought the worst in living memory, Reuters said. The delay in rainfall also led to water shortages in parts of Cote d'Ivoire, according to the United Nations Office for the Coordination of Humanitarian Affairs.

  12. Determinants of outcome of children with type 1 diabetes in the North West Region of Cameroon

    OpenAIRE

    Niba, Loveline Lum

    2016-01-01

    Background: In sub-Saharan Africa the prognosis of children with type 1 diabetes is poor. Many are not diagnosed and those that are diagnosed have a reduced life expectancy (less than one year). This study set out to identify the factors that predict glucose control in children and adolescents with type 1 diabetes in the North West Region of Cameroon. Methods: A hospital based cross-sectional study involving 76 children/adolescents (41 girls and 35 boys, mean age of 15.1 ± 3.1 years) suf...

  13. Petrogenesis of the Neoproterozoic Ngondo Plutonic complex (Cameroon, west central Africa): a case of late-collisional ferro-potassic magmatism

    Science.gov (United States)

    Tagne-Kamga, Gabriel

    2003-04-01

    The Ngondo complex is a late-collisional pluton, which was emplaced around 600 Ma along a N030° E strike-slip shear zone in the southwestern part of the Neoproterozoic Fold Belt of Cameroon. It comprises three successively emplaced plutonic groups of rocks: (i) mafic to felsic intrusive rocks (MFR), (ii) fine-grained granites (FGG) and (iii) coarse-grained granites (CGG). Late aplitic and pegmatite dykes were emplaced along brittle fractures in these plutons. The complex is metaluminous to weakly peraluminous, high-K, calc-alkaline to " trans-alkaline" ferro-potassic, with mineralogical and geochemical characteristic of I-type granites. The plutonic rocks are characterised by high Ba, Sr, Rb and ∑REE concentrations and low Ni and Cr contents in the mafic members. They also display chondrite-normalised REE patterns characterised by variable LREE enrichment, moderate to minor HREE fractionation with moderate to pronounced negative Eu anomalies (Eu/Eu∗: 0.6-0.9 (MFR), 0.2-0.5 (FGG), 0.3-0.7 (CGG)). Trace element distribution patterns for the three plutonic groups are similar with a distinctive depletion in Nb, Sr and Ti relative to other trace elements and a greater enrichment in LILE compared to HFSE. These plutonic groups present distinct evolutionary trends precluding their origin from differentiation of a single parental magma. The geochemical and isotopic data indicate that they derived from partial melting of heterogeneous (meta)-igneous mafic lower crustal materials, having possibly the composition of amphibolitised high-K calc-alkaline basaltic andesites and andesitic metagreywackes. Petrographic evidences such as the presence of quartz-ocelli, xenocrysts of feldspar, fragments of country rocks (migmatitic gneisses) strongly indicate that crustal contamination may have played an important role in the genesis of the plutonic rocks. This contamination process is further supported by the variation of major and trace elements together with Sr-Nd isotopic data

  14. Trade networks in West Africa

    DEFF Research Database (Denmark)

    Walther, Olivier

    2014-01-01

    To date, most of the literature on trade networks in West Africa has considered networks in a metaphorical way. The aim of this paper is to go one step further by showing how social network analysis may be applied to the study of regional trade in West Africa. After a brief review of the literature......, this exploratory paper investigates two main issues related to regional trade. We start by discussing how recent developments in regional trade in West Africa have contributed to challenging the social structure of traders. We then discuss the changes that have affected the spatiality of regional trade by looking...

  15. Timing of Premarital Intercourse in Bandjoun (West Cameroon

    Directory of Open Access Journals (Sweden)

    Zacharie Tsala Dimbuene

    2013-03-01

    Full Text Available This article examined the effects of family environment on the risks of premarital intercourse for male and female youth. Previous research in sub-Saharan Africa (SSA on the linkages between family structures and sexual debut mainly utilized cross-sectional data. In a sample drawn from Cameroon Family and Health Survey (N = 2,166, descriptive and multivariate results showed that youth who resided in nuclear two-parent families, those who reported higher levels of parental monitoring and higher quality of parent–child relationships during childhood and/or adolescence, had significantly lower rates of premarital intercourse. Polygynous families, parent–child communication, orphanhood, and change in family structure were significantly associated with higher rates of premarital intercourse. Programmatic implications for reproductive health interventions in SSA are discussed.

  16. The politics of neoliberal reforms in Africa : State and civil society in Cameroon

    NARCIS (Netherlands)

    Konings, P.J.J.

    2011-01-01

    Neoliberalism has become the dominant development agenda in Africa, but neoliberal experiments have displayed a remarkable diversity in different countries. This book focuses on Cameroon, where the neoliberal project has been influenced by the nation's complex economic and political history. Current

  17. Cameroon.

    Science.gov (United States)

    1992-06-01

    The US profile of Cameroon indicates brief statistics on the population, geography, government, and economy and brief descriptions of the population, the history, government, political conditions, the economy, foreign relations, defense, and relations with the US. Principal government and US officials are furnished. The 1991 estimated population of Cameroon was 11.7 million of which 60% is rural. There are 200 different tribes who speak many African languages and dialects. The French and English languages both have official status. Muslims live in the north and Christians in the south. 80% live in the formerly French east. The growth rate is 3%. There is 65% literacy. Infant mortality is 20%. 70% are agricultural workers, 13% industrial and commercial, and 17% other. The government is an independent republic with an executive and legislative branch. Independence was achieved in 1960. There is 1 ruling party. Traditional courts administer the laws. Traditional rulers are treated as administrative adjuncts. Suffrage is universal adult. The central government budget is 1.4 billion of which 8.7% is for defense. There are 10 provinces and 4 major cities. The seaport city Douala is the largest at 1.5 million. Gross domestic product (GDP) is $12.5 billion with an annual growth rate of 4.3% and an inflation rate of 2%. Growth has been variable since 1988 and reached a low of 2.4% in 1988-89. Oil, natural gas, bauxite, iron core, and timber are natural resources. 27% of the GDP is in agricultural products (cocoa, coffee, cotton, fishing, and forestry). 13% of the GDP is manufacturing and 24% is industry. Exports are valued at $2.9 billion and imports at $2.2 billion. Major markets are France, Netherlands, and the US. Imports include intermediate goods, capital goods, fuel and lubricants, foodstuffs, beverages, and tobacco. Early inhabitants were the Pygmies, followed later by Bantu speakers, and Muslim Fulani. Political consolidation was achieved in 1970 after a period of

  18. Sustainable Development and Corporate Social Responsibility in Sub-Saharan Africa: Evidence from Industries in Cameroon

    Directory of Open Access Journals (Sweden)

    Oyewole Simon Oginni

    2016-05-01

    Full Text Available Present technological innovations and social organizations continue to impose risks and limitations on the efficient performance of the biosphere. Human activities have increasingly short-lived sustainable natural endowments, to the extent that, the multiplier effects have ripples beyond the traditional benefits of economic production and consumption. Therefore, this study addressed practical concerns on how industries in Sub-Saharan Africa promote sustainable development in their corporate social responsibility models, using industries in Cameroon as a case study; it examined economic, social, and environmental components of sustainable development and corporate social responsibility (CSR. Our sample consists of 335 business enterprises from the last Censure Survey of Enterprises in Cameroon. The study adopted a systematic analysis through the Adjusted Residual Test, and the Phi and Cramer’s V tests. Findings revealed that industries in Cameroon prioritize environmental and social dimensions over economic dimensions. However, a few large enterprises implement a broad CSR that promotes sustainable business practices, whereas smaller ones do not; industries in Cameroon implement environmental dimensions of CSR as a safe buffer and a social dimension as philanthropy. Hence, there is no concrete evidence that industries promote sustainable development via CSR in Cameroon. The implementation of a sustainable business model is a precondition for promoting sustainable development via CSR. Industries should realize the concrete value in implementing a sustainable business model that helps to adjust to the complex and increasingly changing business environment.

  19. Legume Diversity Patterns in West Central Africa

    NARCIS (Netherlands)

    Estrella, de la M.; Mateo, M.A.; Wieringa, J.J.; Mackinder, B.; Munoz, J.

    2012-01-01

    Objectives - Species Distribution Models (SDMs) are used to produce predictions of potential Leguminosae diversity in West Central Africa. Those predictions are evaluated subsequently using expert opinion. The established methodology of combining all SDMs is refined to assess species diversity withi

  20. An economic comparison of typical dairy farming systems in South Africa, Morocco, Uganda and Cameroon.

    Science.gov (United States)

    Ndambi, Oghaiki Asaah; Hemme, Torsten

    2009-08-01

    Population growth, urbanisation and increased per capita milk consumption are main reasons for recent increasing milk demand in Africa. Due to globalisation, it is important to know how competitive various production systems are, especially as most governments promote local production and disfavour dairy imports. The TIPI-CAL (Technology Impact, Policy Impact Calculations model) was used to analyse and compare costs and returns of predominant dairy farming systems in South Africa, Morocco, Uganda and Cameroon. Results show that, as farms grew larger in size, family resources (especially land and labour) became insufficient and there was need for their acquisition from external sources. Though extensive dairy farming systems had the lowest cost of milk production (Africa had relatively low costs (Investment (ROI) due to a higher efficiency of input utilisation. It was concluded that, intensification of dairy farming and simultaneously increasing the scale of production will greatly increase productivity of farm inputs, thus recommended for development of the dairy sector in African countries.

  1. A novel sickle cell mutation of yet another origin in Africa: the Cameroon type.

    Science.gov (United States)

    Lapouméroulie, C; Dunda, O; Ducrocq, R; Trabuchet, G; Mony-Lobé, M; Bodo, J M; Carnevale, P; Labie, D; Elion, J; Krishnamoorthy, R

    1992-05-01

    The sickle cell mutation (beta s) arose as at least three independent events in Africa and once in Asia, being termed the Senegal, Benin, Bantu and Indian types respectively. An investigation in Cameroon was carried out to determine whether the atypical sickle genes observed in the neighboring countries are the result of recombination or the presence of a sickle cell mutation of a different genetic origin. It was conducted on 40 homozygous SS patients followed at the Blood Transfusion Center in the capital city of Yaoundé. On 80 beta s chromosomes, 13 exhibited a novel polymorphic pattern that was observed three times in the homozygous state. This chromosome contains an A gamma T gene. The restriction fragment length polymorphism haplotype is different from all the other beta s chromosomes in both the 5' and 3' regions, but has previously been reported in sporadic cases. The (AT)8(T)5 sequence in the -500 region of the beta gene is specific and different from that of the Senegal, Benin, Bantu or Indian beta s genes. All the carriers of this specific chromosome belong to the Eton ethnic group and originate from the Sanaga river valley. This observation strongly argues for yet another independent origin of the sickle cell mutation in Africa, here referred to as the "Cameroon type". The Benin haplotype and a Benin/Bantu recombinant haplotype have been observed in the other studied populations: Ewondo, Bamiléké, Bassa, Yambassa and Boulou.

  2. Transcending Communication Barriers with West Africa.

    Science.gov (United States)

    Ampadu, Lena

    Americans doing business with West Africans are limited in their ability to communicate successfully in that part of the world because of language, stereotyping, and ethnocentrism. Americans must become accustomed to British patterns of speech and writing. Stereotypes of Africa, its people, and its cultures perpetuated by the media keep Americans…

  3. Epidemiology: Malaria in a warmer West Africa

    Science.gov (United States)

    Caminade, C.; Jones, A. E.

    2016-11-01

    Malaria risk in West Africa is expected to fall (western region) or remain the same (eastern region) in response to climate change over the twenty-first century. This is primarily due to extreme temperature conditions projected under a high greenhouse gas emissions scenario.

  4. Mastomys natalensis and Lassa fever, West Africa.

    Science.gov (United States)

    Lecompte, Emilie; Fichet-Calvet, Elisabeth; Daffis, Stéphane; Koulémou, Kékoura; Sylla, Oumar; Kourouma, Fodé; Doré, Amadou; Soropogui, Barré; Aniskin, Vladimir; Allali, Bernard; Kouassi Kan, Stéphane; Lalis, Aude; Koivogui, Lamine; Günther, Stephan; Denys, Christiane; ter Meulen, Jan

    2006-12-01

    PCR screening of 1,482 murid rodents from 13 genera caught in 18 different localities of Guinea, West Africa, showed Lassa virus infection only in molecularly typed Mastomys natalensis. Distribution of this rodent and relative abundance compared with M. erythroleucus correlates geographically with Lassa virus seroprevalence in humans.

  5. West Africa land use and land cover time series

    Science.gov (United States)

    Cotillon, Suzanne E.

    2017-02-16

    Started in 1999, the West Africa Land Use Dynamics project represents an effort to map land use and land cover, characterize the trends in time and space, and understand their effects on the environment across West Africa. The outcome of the West Africa Land Use Dynamics project is the production of a three-time period (1975, 2000, and 2013) land use and land cover dataset for the Sub-Saharan region of West Africa, including the Cabo Verde archipelago. The West Africa Land Use Land Cover Time Series dataset offers a unique basis for characterizing and analyzing land changes across the region, systematically and at an unprecedented level of detail.

  6. Lassa fever: another threat from West Africa.

    Science.gov (United States)

    Brosh-Nissimov, Tal

    2016-01-01

    Lassa fever, a zoonotic viral infection, is endemic in West Africa. The disease causes annual wide spread morbidity and mortality in Africa, and can be imported by travelers. Possible importation of Lassa fever and the potential for the use of Lassa virus as an agent of bioterrorism mandate clinicians in Israel and other countries to be vigilant and familiar with the basic characteristics of this disease. The article reviews the basis of this infection and the clinical management of patients with Lassa fever. Special emphasis is given to antiviral treatment and infection control.

  7. Usability and Interaction Design in West Africa

    DEFF Research Database (Denmark)

    Sørensen, Jannick Kirk

    , with a specific aim at the dissemination of knowledge in field of interaction design both in an academic context, as well as among practitioners. More specifically the paper discusses how interaction design knowledge can be disseminated in West Africa, particularly in Higher Education.......Good usability is important in all ICT solutions. To achieve good usability, a good praxis for interaction design is needed. Usability and interaction design have however emerged and established itself in a North European and US context. The ICT industry in Africa do not have the same resources...... in the field of interaction design as in the developed world. While good usability and good user experiences are important to all users of ICT, the question is whether the methods and techniques that were mainly developed in Scandinavia, Europe and US are suitable for ICT development in Africa? Can ideals...

  8. Survey of the mineral status of pastures and small ruminants in the West Region of Cameroon

    Directory of Open Access Journals (Sweden)

    Njwe, RM.

    1988-01-01

    Full Text Available Four dominant grass species (Hyparrhenia rufa, Melinis minutiflora, Pennisetum purpureum and Sporobolus africanus of natural pastures of the West Region of Cameroon were sampled at 60 sites between September and November of 1985. The grass samples were analysed for calcium, phosphorus, potassium, magnesium, sodium, iron, mangenese, copper and zinc. Serum was also collected from goats and sheep at the same locations where forages were sampled and analysed for calcium, phosphorus, magnesium, zinc and copper. Results showed that P, Mg, A/a, Zn and Cu in forages were generally below the critical level stipulated to satisfy the requirements of grazing livestock in the tropics. Calcium was inadequate in the sera of goats and sheep where as P, Mg, Zn and Cu were adequate. Use of salt licks to supplement intake of mineral elements from grasses by goats and sheep is necessary in the region.

  9. Oral Health Status of the Elderly at Tonga, West Region, Cameroon

    Science.gov (United States)

    Michele Lolita, Yotat; Ashu Michael, Agbor; Hubert, Ntumba; Florence, Djachechi; Jacques, Bolenge

    2015-01-01

    Objectives. The aim of this study was to determine the oral health status of elderly persons in Tonga, West Region of Cameroon. Methodology. This is a cross-sectional study of persons of at least 65 years, living in Tonga village, West Region of Cameroon. Results. A total of 183 persons aged between 65 and 94 years, mean age of 73 years ±7 s.d., 83 (45,4%) males, and 100 (54,6%) females participated in the study. The most represented age range was 65–74 years (60.1%); 86 (47.3%) and elders above 65 constituted 1.8% of the total population. More than a third 117 (41.4%) had visible dental plaque, 117 (48,6%) had periodontal pockets >4 mm, 153 (54,1%) had teeth with total crown destruction, 70 (38.3%) had not lost a tooth, 23 (12.6%) had lost 1 tooth, 19 (10.4%) have lost at least 2 teeth, 100 (55.7%) were partially edentulous at the maxilla and 98 (53.6%) at the mandible, 2 (1.1%) were completely edentulous at the maxilla and 3 (1.6%) at the mandible, and 3.8% had removable dentures. The mean DMF index was 6.11 and 69.4% had dental caries. Risk factors to dental caries were toothbrushing and tobacco consumption while dental plaque was associated to pocket depth of 4–6 mm. Barriers to oral health care included ignorance 47 (25.7%), financial difficulties 124 (67.8%), and distance to the nearest clinic 12 (6.5%). Conclusion. The oral status of the elderly was generally poor. PMID:26633972

  10. Oral Health Status of the Elderly at Tonga, West Region, Cameroon

    Directory of Open Access Journals (Sweden)

    Yotat Michele Lolita

    2015-01-01

    Full Text Available Objectives. The aim of this study was to determine the oral health status of elderly persons in Tonga, West Region of Cameroon. Methodology. This is a cross-sectional study of persons of at least 65 years, living in Tonga village, West Region of Cameroon. Results. A total of 183 persons aged between 65 and 94 years, mean age of 73 years ±7 s.d., 83 (45,4% males, and 100 (54,6% females participated in the study. The most represented age range was 65–74 years (60.1%; 86 (47.3% and elders above 65 constituted 1.8% of the total population. More than a third 117 (41.4% had visible dental plaque, 117 (48,6% had periodontal pockets >4 mm, 153 (54,1% had teeth with total crown destruction, 70 (38.3% had not lost a tooth, 23 (12.6% had lost 1 tooth, 19 (10.4% have lost at least 2 teeth, 100 (55.7% were partially edentulous at the maxilla and 98 (53.6% at the mandible, 2 (1.1% were completely edentulous at the maxilla and 3 (1.6% at the mandible, and 3.8% had removable dentures. The mean DMF index was 6.11 and 69.4% had dental caries. Risk factors to dental caries were toothbrushing and tobacco consumption while dental plaque was associated to pocket depth of 4–6 mm. Barriers to oral health care included ignorance 47 (25.7%, financial difficulties 124 (67.8%, and distance to the nearest clinic 12 (6.5%. Conclusion. The oral status of the elderly was generally poor.

  11. Typology of Natural Hazards and Assessment of Associated Risks in the Mount Bambouto Caldera (Cameroon Line, West Cameroon)

    Institute of Scientific and Technical Information of China (English)

    Ghislain T. ZANGMO; Armand D. KAGOU; David G. NKOUATHIO; Pierre WANDJI

    2009-01-01

    Mount Bambouto is a polygenic stratovoicano of the Cameroon Volcanic Line, built between 21 Ma and 4.5 Ma. It is situated approximately 200 km NE of Mount Cameroon, between 09°55' and 10°15' longitude east and, 05°25' and 05°50' latitude north. The volcano covers an area of (13×8 km). Mount Bambouto is characterized by several natural hazards of different origins: meteorological, such as landslides and rock falls; anthropogenic, such as bushfires, tribal wars and deforestation; and volcanological, such as volcanic eruption. The thematic map shows that 55-60% of the caldera has high probability of occurrence of mass movement. The caldera has a high population density (3000 inhabitants), which increases the level of risk, evaluated at approximately $US3.8 million for patrimony, 3000 civilian deaths and destruction of biodiversity.

  12. New emerging West Africa Ebola 2014: the present global threaten

    Directory of Open Access Journals (Sweden)

    Viroj Wiwanitkit

    2014-07-01

    Full Text Available New emerging West Africa Ebola 2014 is the present global threaten. It is a new emerging viral infection that primarily occurred in West Africa and poses the possible trend of worldwide pandemic. The 2014 West Africa Ebola outbreak is the most severe in recorded history in regards to both the number of human cases and fatalities. World Health Organization calls for global concern and attempts to stop the spread of this emerging viral infection. In this brief review, the author presents and discusses on the clinical feature of the new emerging West Africa Ebola 2014.

  13. New emerging West Africa Ebola 2014:the present global threaten

    Institute of Scientific and Technical Information of China (English)

    Viroj Wiwanitkit

    2014-01-01

    New emerging West Africa Ebola 2014 is the present global threaten. It is a new emerging viral infection that primarily occurred in West Africa and poses the possible trend of worldwide pandemic. The 2014 West Africa Ebola outbreak is the most severe in recorded history in regards to both the number of human cases and fatalities. World Health Organization calls for global concern and attempts to stop the spread of this emerging viral infection. In this brief review, the author presents and discusses on the clinical feature of the new emerging West Africa Ebola 2014.

  14. An Exploratory Multi-Method Analysis of Cybercrime Perpetrators' Perceptions to Combat Cyber Crime in Sub Saharan Africa: The Case of Cameroon

    Science.gov (United States)

    Akuta, Eric Agwe-Mbarika

    2012-01-01

    The past decade has projected much of Africa as a haven for cybercrime perpetration. This view was widely evidenced in Cameroon, a country regarded as a miniature Africa due to its diverse socio-cultural, economic and political characteristics. In spite of efforts by government to curb cybercrime, the perpetration rate has not declined due to a…

  15. Distribution of knock-down resistance mutations in Anopheles gambiae molecular forms in west and west-central Africa

    Directory of Open Access Journals (Sweden)

    Caccone Adalgisa

    2008-04-01

    Full Text Available Abstract Background Knock-down resistance (kdr to DDT and pyrethroids in the major Afrotropical vector species, Anopheles gambiae sensu stricto, is associated with two alternative point mutations at amino acid position 1014 of the voltage-gated sodium channel gene, resulting in either a leucine-phenylalanine (L1014F, or a leucine-serine (L1014S substitution. In An. gambiae S-form populations, the former mutation appears to be widespread in west Africa and has been recently reported from Uganda, while the latter, originally recorded in Kenya, has been recently found in Gabon, Cameroon and Equatorial Guinea. In M-form populations surveyed to date, only the L1014F mutation has been found, although less widespread and at lower frequencies than in sympatric S-form populations. Methods Anopheles gambiae M- and S-form specimens from 19 sites from 11 west and west-central African countries were identified to molecular form and genotyped at the kdr locus either by Hot Oligonucleotide Ligation Assay (HOLA or allele-specific PCR (AS-PCR. Results The kdr genotype was determined for about 1,000 An. gambiae specimens. The L1014F allele was found at frequencies ranging from 6% to 100% in all S-form samples (N = 628, with the exception of two samples from Angola, where it was absent, and coexisted with the L1014S allele in samples from Cameroon, Gabon and north-western Angola. The L1014F allele was present in M-form samples (N = 354 from Benin, Nigeria, and Cameroon, where both M- and S-forms were sympatric. Conclusion The results represent the most comprehensive effort to analyse the overall distribution of the L1014F and L1014S mutations in An. gambiae molecular forms, and will serve as baseline data for resistance monitoring. The overall picture shows that the emergence and spread of kdr alleles in An. gambiae is a dynamic process and that there is marked intra- and inter-form heterogeneity in resistance allele frequencies. Further studies are needed to

  16. Lithostratigraphy, volcanism, paleomagnetism and palynology of Quaternary lacustrine deposits from Barombi Mbo (West Cameroon): Preliminary results

    Science.gov (United States)

    Maley, J.; Livingstone, D. A.; Giresse, P.; Thouveny, N.; Brenac, P.; Kelts, K.; Kling, G.; Stager, C.; Haag, M.; Fournier, M.; Bandet, Y.; Williamson, D.; Zogning, A.

    1990-08-01

    We present preliminary results from the study of 23.50-m core from Lake Barombi Mbo, representing the last 25,000 years. The lake is in an explosion crater formed during Quaternary time. The very laminated sediment is composed mostly of clay containing 5-10% organic carbon. Each couplet is commonly composed of a basal lamina rich in quartz, plant debris, muscovite and sponge spicules, and of a more clayey upper lamina often with siderite. A perturbed section near the base of the core, before ca. 21,000 yr B.P., could be the result of a violent release of gas, such CO 2, comparable to the recent Nyos gas eruption. The paleomagnetic studies exhibit high-frequency oscillations interpreted as paleosecular variations of the local geomagnetic field. This first record obtained on the African continent can be closely compared to the type record obtained in Western Europe. The pollen results demonstrate the presence of a forest refuge in West Cameroon during the last great arid period, ca. 18,000 yr B.P. When equatorial forest was broken up, elements of montane vegetation spread to the lowlands. These phenomena resulted from a drying and cooling climate.

  17. [Epidemics and colonial medicine in West Africa].

    Science.gov (United States)

    Becker, C; Collignon, R

    1998-01-01

    We studied colonial medical practices and health policies in West Africa, which has faced endemics and epidemics that have affected entire societies. We found that attempts to centralize the organization of colonial medicine, which began in the late 19th Century, were limited until the end of World War I. Research and control programs expanded after 1920, concentrating on epidemics, but largely ignoring many major health problems, such as measles, whooping cough and malnutrition, the importance of which were not recognized until after World War II. This appraisal of colonial medicine highlights the difficulties of introducing modern medicine and its ideas into African societies. There have been various social reactions, resulting in the current duality in which traditional and modern medicine coexist.

  18. Vulnerability to climate change of cocoa in West Africa: Patterns, opportunities and limits to adaptation.

    Science.gov (United States)

    Schroth, Götz; Läderach, Peter; Martinez-Valle, Armando Isaac; Bunn, Christian; Jassogne, Laurence

    2016-06-15

    The West African cocoa belt, reaching from Sierra Leone to southern Cameroon, is the origin of about 70% of the world's cocoa (Theobroma cacao), which in turn is the basis of the livelihoods of about two million farmers. We analyze cocoa's vulnerability to climate change in the West African cocoa belt, based on climate projections for the 2050s of 19 Global Circulation Models under the Intergovernmental Panel on Climate Change intermediate emissions scenario RCP 6.0. We use a combination of a statistical model of climatic suitability (Maxent) and the analysis of individual, potentially limiting climate variables. We find that: 1) contrary to expectation, maximum dry season temperatures are projected to become as or more limiting for cocoa as dry season water availability; 2) to reduce the vulnerability of cocoa to excessive dry season temperatures, the systematic use of adaptation strategies like shade trees in cocoa farms will be necessary, in reversal of the current trend of shade reduction; 3) there is a strong differentiation of climate vulnerability within the cocoa belt, with the most vulnerable areas near the forest-savanna transition in Nigeria and eastern Côte d'Ivoire, and the least vulnerable areas in the southern parts of Cameroon, Ghana, Côte d'Ivoire and Liberia; 4) this spatial differentiation of climate vulnerability may lead to future shifts in cocoa production within the region, with the opportunity of partially compensating losses and gains, but also the risk of local production expansion leading to new deforestation. We conclude that adaptation strategies for cocoa in West Africa need to focus at several levels, from the consideration of tolerance to high temperatures in cocoa breeding programs, the promotion of shade trees in cocoa farms, to policies incentivizing the intensification of cocoa production on existing farms where future climate conditions permit and the establishment of new farms in already deforested areas.

  19. Markets, Climate Change and Food Security in West Africa

    Science.gov (United States)

    Brown, Molly E.; Hintermann, Beat; Higgins, Nathaniel

    2009-01-01

    West Africa is one of the most food insecure regions of the world. Sharply increased food and energy prices in 2008 brought the role of markets in food access and availability around the world into the spotlight, particularly in urban areas. The period of high prices had the immediate consequence of sharply increasing the number of hungry people in the region without boosting farmer incomes significantly. In this article, the interaction between markets, food prices, agricultural technology and development is explored in the context of West Africa. To improve food security in West Africa, sustained commitment to investment in the agriculture sector will be needed to provide some protection against global swings in both production and world markets. Climate change mitigation programs are likely to force global energy and commodity price increases in the coming decades, putting pressure on regions like West Africa to produce more food locally to ensure stability in food security for the most vulnerable.

  20. Influence of Processing Methods on Proximate Composition and Dieting of Two Amaranthus Species from West Cameroon

    Science.gov (United States)

    Suffo Kamela, Arnaud Landry; Mouokeu, Raymond Simplice; Ashish, Rawson; Maffo Tazoho, Ghislain; Glory Moh, Lamye; Pamo Tedonkeng, Etienne

    2016-01-01

    The effects of various processing methods on the proximate composition and dieting of Amaranthus hybridus and Amaranthus cruentus from West Cameroon were investigated in this study. Both amaranths leaves were subjected to same treatments (sun-dried and unsliced, sliced and cooked), milled, and analysed for their mineral and proximate composition. Thirty-Six Wistar albino rats of 21 to 24 days old were distributed in six groups and fed for 14 days with 10% protein based diets named D0 (protein-free diet), DI (egg white as reference protein), DII (sun-dried and unsliced A. hybridus), DIII (cooked and sliced A. hybridus), DIV (sun-dried and unsliced A. cruentus), and DV (cooked and sliced A. cruentus). The protein bioavailability and haematological and biochemical parameters were assessed in rats. The results showed that K, P, Mg, Zn, and Fe had the higher content in both samples regardless of processing method. The sun-dried and unsliced A. cruentus contained the highest value of crude protein 32.22 g/100 g DM (dry matter) while the highest crude lipid, 3.80 and 2.58%, was observed, respectively, in sun-dried and unsliced A. hybridus and cooked and sliced A. cruentus. Cooked and sliced A. hybridus and A. cruentus contained high crude fiber of 14 and 12.18%, respectively. Rats fed with diet DIII revealed the best protein bioavailability and haematological parameters whereas 100% mortality rate was recorded with group fed with diet DIV. From this study, it is evident that cooked and sliced A. hybridus and A. cruentus could play a role in weight reduction regimes. PMID:28078277

  1. The historiography of Islam in West Africa : an anthropologist's view

    NARCIS (Netherlands)

    Soares, B.F.

    2014-01-01

    In this article, I focus on the historiography of Islam in West Africa while also reflecting upon and assessing existing scholarship in the broader field of the study of Islam in Africa. My position as an anthropologist who conducts historical research informs my perspective in evaluating the curren

  2. Forest gradients in West Africa. A spatial gradient analysis.

    NARCIS (Netherlands)

    Rompaey, van R.S.A.R.

    1993-01-01

    The tropical rain forests of West Africa, west of the Dahomey interval, once covered some 40 million ha. Being on the western fringe of the African continent, they receive abundant rainfall from the SW monsoon. Further inland, rainfall gradually decreases and the forests give way to savanna and ulti

  3. Bacillus anthracis Diversity and Geographic Potential across Nigeria, Cameroon and Chad: Further Support of a Novel West African Lineage.

    Science.gov (United States)

    Blackburn, Jason K; Odugbo, Moses Ode; Van Ert, Matthew; O'Shea, Bob; Mullins, Jocelyn; Perreten, Vincent; Perrenten, Vincent; Maho, Angaya; Hugh-Jones, Martin; Hadfield, Ted

    2015-01-01

    Zoonoses, diseases affecting both humans and animals, can exert tremendous pressures on human and veterinary health systems, particularly in resource limited countries. Anthrax is one such zoonosis of concern and is a disease requiring greater public health attention in Nigeria. Here we describe the genetic diversity of Bacillus anthracis in Nigeria and compare it to Chad, Cameroon and a broader global dataset based on the multiple locus variable number tandem repeat (MLVA-25) genetic typing system. Nigerian B. anthracis isolates had identical MLVA genotypes and could only be resolved by measuring highly mutable single nucleotide repeats (SNRs). The Nigerian MLVA genotype was identical or highly genetically similar to those in the neighboring countries, confirming the strains belong to this unique West African lineage. Interestingly, sequence data from a Nigerian isolate shares the anthrose deficient genotypes previously described for strains in this region, which may be associated with vaccine evasion. Strains in this study were isolated over six decades, indicating a high level of temporal strain stability regionally. Ecological niche models were used to predict the geographic distribution of the pathogen for all three countries. We describe a west-east habitat corridor through northern Nigeria extending into Chad and Cameroon. Ecological niche models and genetic results show B. anthracis to be ecologically established in Nigeria. These findings expand our understanding of the global B. anthracis population structure and can guide regional anthrax surveillance and control planning.

  4. Bacillus anthracis Diversity and Geographic Potential across Nigeria, Cameroon and Chad: Further Support of a Novel West African Lineage.

    Directory of Open Access Journals (Sweden)

    Jason K Blackburn

    Full Text Available Zoonoses, diseases affecting both humans and animals, can exert tremendous pressures on human and veterinary health systems, particularly in resource limited countries. Anthrax is one such zoonosis of concern and is a disease requiring greater public health attention in Nigeria. Here we describe the genetic diversity of Bacillus anthracis in Nigeria and compare it to Chad, Cameroon and a broader global dataset based on the multiple locus variable number tandem repeat (MLVA-25 genetic typing system. Nigerian B. anthracis isolates had identical MLVA genotypes and could only be resolved by measuring highly mutable single nucleotide repeats (SNRs. The Nigerian MLVA genotype was identical or highly genetically similar to those in the neighboring countries, confirming the strains belong to this unique West African lineage. Interestingly, sequence data from a Nigerian isolate shares the anthrose deficient genotypes previously described for strains in this region, which may be associated with vaccine evasion. Strains in this study were isolated over six decades, indicating a high level of temporal strain stability regionally. Ecological niche models were used to predict the geographic distribution of the pathogen for all three countries. We describe a west-east habitat corridor through northern Nigeria extending into Chad and Cameroon. Ecological niche models and genetic results show B. anthracis to be ecologically established in Nigeria. These findings expand our understanding of the global B. anthracis population structure and can guide regional anthrax surveillance and control planning.

  5. How to win a football match in Cameroon : an anthropological study of Africa's most popular sport

    NARCIS (Netherlands)

    Pannenborg, A.

    2008-01-01

    Footballers Essomba and Ashu, team manager Kalla and spiritual adviser Zé are the key characters in this anthropological study of football in Cameroon, which is based on research carried out in 2003. It might seem that a well-organized club with professional executives, a team of talented players an

  6. The late holocene palaeoenvironment in the Lake Njupi area, west Cameroon: implications regarding the history of Lake Nyos

    Science.gov (United States)

    Zogning, Appolinaire; Giresse, Pierre; Maley, Jean; Gadel, François

    1997-04-01

    Lake Njupi, 1 km east of Lake Nyos, on the Cameroon Volcanic Line, was formed by the damming of a local crustal depression. Two cores from Lake Nyos were analysed which penetrated sediments at the margin of the lake. The older deposits give an age of 3400 years BP and this date is proposed as a minimum age for Lake Njupi. Sedimentological, palynological and geochemical studies of a 2 m section provide an opportunity to reconstruct the Late Holocene environmental history. It is an organic-rich deposit (organic carbon up to 30%) with an abundant Silicospongia spicules fraction. An obvious sedimentary homogeneity is interrupted by 5 fine to coarse layers with sandy quartz and lignitic remains. Such inputs were denoted by carbohydrate maxima or sometimes by phenolic compounds. This study confirms the evidence of an arid period culminating between 2500 and 2000 yrs BP. This crisis began around 3000 yrs BP in the rain forest area of West Cameroon and also further to the south in Congo. Lake Njupi, situated today in a mostly grassland savanna environment known as the "Grass Fields", provides evidence for environmental changes from a mosaic of forest and savanna before 2500 years BP to a savanna characterised by high grass pollen contents (75 to 85%), with small islands of forest. The mountain vegetation characterised by Podocarpus and Olea capensis retreated around 2300 years BP at the time Elaeis guineensis (the Oil Palm) began its extension as a pioneer tree, later providing opportunities for its domestication by man.

  7. Serosurveillance of viral pathogens circulating in West Africa

    OpenAIRE

    O’Hearn, Aileen E.; Voorhees, Matthew A.; Fetterer, David P.; Wauquier, Nadia; Coomber, Moinya R.; Bangura, James; Fair, Joseph N.; Gonzalez, Jean-Paul; Schoepp, Randal J.

    2016-01-01

    Background Sub-Saharan Africa is home to a variety of pathogens, but disease surveillance and the healthcare infrastructure necessary for proper management and control are severely limited. Lassa virus, the cause of Lassa fever, a severe hemorrhagic fever in humans is endemic in West Africa. In Sierra Leone at the Kenema Government Hospital Lassa Diagnostic Laboratory, up to 70 % of acute patient samples suspected of Lassa fever test negative for Lassa virus infection. This large amount of ac...

  8. Current practice of epidemiology in Africa: highlights of the 3rd conference of the African epidemiological association and 1st conference of the Cameroon society of epidemiology, Yaoundé, Cameroon, 2014.

    Science.gov (United States)

    Nkwescheu, Armand Seraphin; Fokam, Joseph; Tchendjou, Patrice; Nji, Akindeh; Ngouakam, Hermann; Andre, Bita Fouda; Joelle, Sobngwi; Uzochukwu, Benjamin; Akinroye, Kingsley; Mbacham, Wilfred; Colizzi, Vittorio; Leke, Rose; Victora, Cesar

    2015-01-01

    As the study of disease occurrence and health indicators in human populations, Epidemiology is a dynamic field that evolves with time and geographical context. In order to update African health workers on current epidemiological practices and to draw awareness of early career epidemiologists on concepts and opportunities in the field, the 3(rd) African Epidemiology Association and the 1st Cameroon Society of Epidemiology Conference was organized in June 2-6, 2014 at the Yaoundé Mont Febe Hotel, in Cameroon. Under the theme«Practice of Epidemiology in Africa: Stakes, Challenges and Perspectives», the conference attracted close to five hundred guest and participants from all continents. The two main programs were the pre-conference course for capacity building of African Early Career epidemiologists, and the conference itself, providing a forum for scientific exchanges on recent epidemiological concepts, encouraging the use of epidemiological methods in studying large disease burden and neglected tropical diseases; and highlighting existing opportunities.

  9. The lion in West Africa is critically endangered.

    Directory of Open Access Journals (Sweden)

    Philipp Henschel

    Full Text Available The African lion has declined to 500 km² PAs and compiled evidence of lion presence/absence for a further eight PAs. All PAs were situated within Lion Conservation Units, geographical units designated as priority lion areas by wildlife experts at a regional lion conservation workshop in 2005. Lions were confirmed in only 4 PAs, and our results suggest that only 406 (273-605 lions remain in West Africa, representing <250 mature individuals. Confirmed lion range is estimated at 49,000 km², or 1.1% of historical range in West Africa. PAs retaining lions were larger than PAs without lions and had significantly higher management budgets. We encourage revision of lion taxonomy, to recognize the genetic distinctiveness of West African lions and highlight their potentially unique conservation value. Further, we call for listing of the lion as critically endangered in West Africa, under criterion C2a(ii for populations with <250 mature individuals. Finally, considering the relative poverty of lion range states in West Africa, we call for urgent mobilization of investment from the international community to assist range states to increase management effectiveness of PAs retaining lions.

  10. Mapping of schistosomiasis and soil-transmitted helminthiasis in the regions of centre, East and West Cameroon.

    Directory of Open Access Journals (Sweden)

    Louis-Albert Tchuem Tchuenté

    Full Text Available BACKGROUND: Schistosomiasis and soil-transmitted helminthiasis (STH are widely distributed in Cameroon. Although mass drug administration (MDA of mebendazole is implemented nationwide, treatment with praziquantel was so far limited to the three northern regions and few health districts in the southern part of Cameroon, based on previous mapping conducted 25 years ago. To update the disease distribution map and determine where treatment with praziquantel should be extended, mapping surveys were conducted in three of the seven southern regions of Cameroon, i.e. Centre, East and West. METHODOLOGY: Parasitological surveys were conducted in April-May 2010 in selected schools in all 63 health districts of the three targeted regions, using appropriate research methodologies, i.e. Kato-Katz and urine filtration. PRINCIPAL FINDINGS: The results showed significant variation of schistosomiasis and STH prevalence between schools, villages, districts and regions. Schistosoma mansoni was the most prevalent schistosome species, with an overall prevalence of 5.53%, followed by S. haematobium (1.72% and S. guineensis (0.14%. The overall prevalence of schistosomiasis across the three regions was 7.31% (95% CI: 6.86-7.77%. The prevalence for Ascaris lumbricoides was 11.48 (95% CI: 10.93-12.04%, Trichuris trichiura 18.22% (95% CI: 17.56-18.90% and hookworms 1.55% (95% CI: 1.35-1.78%, with an overall STH prevalence of 24.10% (95% CI: 23.36-24.85% across the three regions. STH was more prevalent in the East region (46.57%; 95% CI: 44.41-48.75% in comparison to the Centre (25.12; 95% CI: 24.10-26.17% and West (10.49%; 95% CI: 9.57-11.51% regions. CONCLUSIONS/SIGNIFICANCE: In comparison to previous data, the results showed an increase of schistosomiasis transmission in several health districts, whereas there was a significant decline of STH infections. Based on the prevalence data, the continuation of annual or bi-annual MDA for STH is recommended, as well as an

  11. The lion in West Africa is critically endangered.

    Science.gov (United States)

    Henschel, Philipp; Coad, Lauren; Burton, Cole; Chataigner, Beatrice; Dunn, Andrew; MacDonald, David; Saidu, Yohanna; Hunter, Luke T B

    2014-01-01

    The African lion has declined to lions from other extant African populations. Interventions to save West African lions are urgently required. However formulating effective conservation strategies has been hampered by a lack of data on the species' current distribution, status, and potential management deficiencies of protected areas (PAs) harboring lions. Our study synthesized available expert opinion and field data to close this knowledge gap, and formulate recommendations for the conservation of West African lions. We undertook lion surveys in 13 large (>500 km²) PAs and compiled evidence of lion presence/absence for a further eight PAs. All PAs were situated within Lion Conservation Units, geographical units designated as priority lion areas by wildlife experts at a regional lion conservation workshop in 2005. Lions were confirmed in only 4 PAs, and our results suggest that only 406 (273-605) lions remain in West Africa, representing lion range is estimated at 49,000 km², or 1.1% of historical range in West Africa. PAs retaining lions were larger than PAs without lions and had significantly higher management budgets. We encourage revision of lion taxonomy, to recognize the genetic distinctiveness of West African lions and highlight their potentially unique conservation value. Further, we call for listing of the lion as critically endangered in West Africa, under criterion C2a(ii) for populations with lion range states in West Africa, we call for urgent mobilization of investment from the international community to assist range states to increase management effectiveness of PAs retaining lions.

  12. African women in political leadership : a comparative study of cameroon (1192-2011) and SOuth Africa (1994-2011) / G.M Ashu

    OpenAIRE

    Ashu, G M

    2012-01-01

    The main aim of the study was to compare the state of women's political representation in the leadership structures of South Africa and Cameroon after almost two decades of multi-party politics in these two African states. The objectives were: to examine the structures and mechanisms that have been put in place in both countries to promote and advance gender equality and women's empowerment; to find out the obstacles which inhibit women's political representation or their ad...

  13. Teaching in West Africa: Dig beneath the Surface

    Science.gov (United States)

    Briam, Carol

    2007-01-01

    In this article, the author shares her experience teaching English to adult learners at the American Cultural Center in Dakar, Senegal, a poor, primarily Muslim country and former French colony in West Africa. Her class was composed of about 30 students, whose age ranged from about 18 to 50. They were mostly men and mostly Senegalese, along with a…

  14. A characterization of rice-growing environments in West Africa.

    NARCIS (Netherlands)

    Andriesse, W.; Fresco, L.O.

    1991-01-01

    Building on past classifications, this article proposes a comprehensive characterization of rice-growing environments in West Africa on the basis of ecological and agronomic parameters. Using climate, soils, toposequence, land types and rice cropping system as classificatory principles, 18 different

  15. Fonio (Digitaria exilis) in West Africa: towards improving nutrient quality

    NARCIS (Netherlands)

    Koreissi, Y.

    2015-01-01

    Fonio (Digitaria exilis) in West Africa: Towards improving nutrient quality Abstract Hidden hunger affects a far greater percentage of the world’s population with iron and zinc deficiencies being the most common, particularly affecting women of reproductive ag

  16. West Africa Land Use Land Cover Time Series

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This series of three-period land use land cover (LULC) datasets (1975, 2000, and 2013) aids in monitoring change in West Africa’s land resources (exception is...

  17. Understanding the productivity of cassava in West Africa

    NARCIS (Netherlands)

    Ezui, Kodjovi Senam

    2017-01-01

    Drought stress and sub-optimal soil fertility management are major constraints to crop production in general and to cassava (Manihot esculenta Crantz) in particular in the rain-fed cropping systems in West Africa. Cassava is an important source of calories for millions of smallholder households in s

  18. The epidemiology and control of onchocerciasis in West-Africa

    NARCIS (Netherlands)

    J.H.F. Remme

    1989-01-01

    textabstractThe present thesis deals with research which has been undertaken since 1983 with the aim of finding answers to the three main epidemiological questions which have been discussed above, i.e. I.-What are the epidemiological patterns of ocular onchocerciasis in West Africa and what is the g

  19. West Africa's deepwater future

    Energy Technology Data Exchange (ETDEWEB)

    McLennan, James; Williams, Stewart

    2005-07-01

    The article surveys the development in the petroleum activities in Africa particularly in the dominating nations Angola ad Nigeria. Economic and social aspects are mentioned as well as the necessity of deepwater exploitation as the resources in more shallow waters become depleted.

  20. West Africa land use land cover time series

    Science.gov (United States)

    Tappan, G. Gray; Cushing, W. Matthew; Cotillon, Suzanne E.; Mathis, Melissa L.; Hutchinson, John A.; Dalsted, K. J.

    2016-01-01

    The West Africa Land Use Dynamics Project provides AGRHYMET and its 17 participating countries a comprehensive two-kilometer (2-km) resolution land use land cover (LULC) dataset of the region for three time periods; 1975, 2000, and 2013. Hundreds of Landsat images were visually interpreted to develop a 2-km LULC dataset for each of the three time periods. To assist in validating the interpretations, thousands of aerial photographs and high-resolution satellite images were used. From the initial datasets produced by national teams, the U.S. Geological Survey (USGS) conducted an independent, detailed review of the interpretations. In concurrence with the respective country teams, the data have been revised to produce an accurate and consistent LULC assessment from within the countries and respective transboundary areas. This West Africa Land Use Dynamics Project represents an effort to document and quantify the impacts of change in both time and space, of the environmental and land resource trends across West Africa. The project was carried out through the AGRHYMET Regional Center in Niamey, Niger, in partners from 17 participating countries, the Sahel Institute (INSAH), the USGS Earth Resources Observation and Science (EROS), and with major support from the U.S. Agency for International Development (USAID) West Africa Regional Program. The overarching goal of the West Africa Land Use Dynamics Project is to promote the awareness of the trends and use of spatial information about natural resource trends among national and regional decision-makers. For a complete description of project visit https://eros.usgs.gov/westafrica

  1. Education and Koranic Literacy in West Africa

    OpenAIRE

    Easton, Peter

    1999-01-01

    The note examines the practical, and literate skills that students acquire at different levels in West African Koranic schools. It is a long-standing parallel system of education, yet, relatively unknown to development planers, thus seldom taken into explicit account in their policies, and strategies. Islamic educational systems have been present since the seventh century, and by the tenth ...

  2. Potential Climate Effects of Dust Aerosols' over West Africa

    Science.gov (United States)

    JI, Z.; Wang, G.; Pal, J. S.; Yu, M.

    2014-12-01

    Climate in West Africa is under the influence of the West African monsoon circulation and mineral dust emitted from the Sahara desert (which is the world's largest source of mineral dust emission). Dust aerosols alter the atmospheric radiative fluxes and act as cloud condensation nuclei in the process of emission, transportation and deposition. However, our understanding regarding how dust aerosols influence the present-day and future climate of West Africa is very limited. In this study, a regional climate model RegCM4.3.4-CLM4.5 is used to investigate the potential climatic effects of dust aerosols both in present (1981-2000) and future (2081-2100) periods over WA. First, the model performance and dust climatic effects are evaluated. The contribution of dust climatic effects under RCP8.5 scenario and their confounding effects with land use change are assessed. Our results indicate that the model can reproduce with reasonable accuracy the spatial and temporal distribution of climatology, aerosol optical depth and surface concentration over WA. The shortwave radiative forcing of dust is negative in the surface and positive in the atmosphere, with greater changes in JJA and MAM compared to those in SON and DJF. Over most of West Africa, cooling is the dominant effect on temperature. Their impact on precipitation features a dipole pattern, with decrease in the north and increase in the south of West Africa. Despite the dust-induced decrease of precipitation amount, dusts cause extreme precipitation to increase. To evaluate the uncertainties surrounding our modeling results, sensitivity experiments driven by ICBC from MIROC-ESM and CESM and their dynamic downscaling results are used for comparisons. Results from these sensitivity experiments indicate that the impact of dust aerosols on present and future climate is robust.

  3. Mobile pastoralists in Central and West Africa: between conflict, mobile telephony and (im)mobility.

    Science.gov (United States)

    De Bruijn, M; Amadou, A; Lewa Doksala, E; Sangaré, B

    2016-11-01

    The livelihoods of the Fulani mobile pastoralists in the Sahel, West and Central Africa are characterised by mobility (related to the needs of their animals), extensive social networks, and a focus on social ties as the basis of status and influence ('wealth in people'). The Sahel environment in which many Fulani nomads live has become embroiled in jihadism, conflict, and violence; at the same time, this region has experienced an increase in opportunities to connect through the wireless mobile communication system. This paper analyses the triangle of mobility, communication, and insecurity in order to understand the present-day situation of the nomadic and semi-nomadic Fulani pastoralists and their identity dynamics. The Fulani find themselves caught in between these conflicts, which end their mobility and often lead to the loss of their herds. Will they be able to keep their mobile lifestyle and identity? This article is based on qualitative case studies and the biographical narratives of nomadic and semi-nomadic pastoralists who have lived through conflict and violence in Cameroon, Chad and Mali. These case studies show that, despite the fact that mobile pastoralism has become difficult as a consequence of the conflicts and loss of cattle, the 'mobile' identity is very present and reinforced with the help of mobile telephony, through which social networks and 'wealth in people' are sustained.

  4. Heat impact on schoolchildren in Cameroon, Africa: potential health threat from climate change

    Directory of Open Access Journals (Sweden)

    Tord Kjellstrom

    2010-11-01

    Full Text Available Background: Health impacts related to climate change are potentially an increasing problem in Cameroon, especially during hot seasons when there are no means for protective and adaptive actions. Objective: To describe environmental conditions in schools and to evaluate the impact of heat on schoolchildren's health during school days in the Cameroon cities of Yaoundé and Douala. Methods: Schoolchildren (N=285 aged 12–16 years from public secondary schools completed a questionnaire about their background, general symptoms, and hot feelings in a cross-sectional study. In Yaoundé, 50 schoolchildren were individually interviewed during school days about hourly symptoms (fatigue, headache, and feeling very hot and performance. Lascar dataloggers were used to measure indoor classroom temperatures and humidity. Results: There was a significant correlation between daily indoor temperature and the percentages of schoolchildren who felt very hot, had fatigue, and headaches in Yaoundé. A high proportion of schoolchildren felt very hot (48%, had fatigue (76%, and headaches (38% in Yaoundé. Prevalences (% were higher among girls than boys for headaches (58 vs 39, feeling ‘very hot overall’ (37 vs 21, and ‘very hot in head’ (21 vs 18. Up to 62% were absentminded and 45% had slow writing speed. High indoor temperatures of 32.5°C in Yaoundé and 36.6°C in Douala were observed in school. Conclusions: Headache, fatigue, and feeling very hot associated with high indoor air temperature were observed among schoolchildren in the present study. Longitudinal data in schools are needed to confirm these results. School environmental conditions should be improved in order to enhance learning.

  5. Research needs for lion conservation in West and Central Africa.

    Science.gov (United States)

    Bauer, Hans; De Iongh, Hans H; Princée, Frank P; Ngantou, Daniel

    2003-08-01

    The lion has historically probably been widespread at low densities in West and Central Africa, nowadays they are largely restricted to small isolated populations inside protected areas. The total number is probably between 1200 and 2700, the best possible guesstimate would be 1700. Mankind is the main cause for the suspected decline of lion populations, both inside and outside protected areas. Very little research has been done on West and Central African lions a few examples are summarized here. The international community is slowly becoming aware of threats to lions in the region and some initiatives for lion conservation have started.

  6. Investigative Journalism and Human Trafficking in West Africa

    Directory of Open Access Journals (Sweden)

    Veronika Gyuracz

    2016-01-01

    Full Text Available Investigative journalism that aims to prise out information that the state or certain businesses want to keep undisclosed has been unthinkable under many postcolonial African regimes. However, since the promulgation of democratic constitutions, a generation of ambitious investigative journalists has grown up in Africa. In order to show how journalism has changed, the paper brings Anas Aremeyaw Anas’s activities into focus. Anas’s single-minded mission to bring justice has targeted organisations involved in human trafficking, smuggling, and forced labour in West African countries since 2010. Although his team’s way of gathering information raises moral concerns about undercover journalism, their efforts illustrate that human trafficking is widespread among the countries of West and Central Africa. Therefore, the author suggests that both the AU and ECOWAS must create a more stable legal environment for investigative journalists, as their reports can help these institutions and national governments protect human rights.

  7. Climate change impacts on runoff in West Africa: a review

    OpenAIRE

    Roudier, P.; A. Ducharne; Feyen, L.

    2014-01-01

    International audience; This review summarizes the impacts of climate change on runoff in West Africa, assesses the uncertainty in the projections and describes future research needs for the region. To do so, we constitute a meta-database made of 19 studies and 301 future runoff change values. The future tendency in streamflow developments is overall very uncertain (median of the 301 points is 0% and mean +5.2%), except for (i) the Gambia River, which exhibits a significant negative change (m...

  8. Intense convection over West Africa during AMMA SOP3 experiment

    Science.gov (United States)

    Lenouo, André; Sall, Saïdou Moustapha; Badiane, Daouda; Gaye, Amadou Thierno; Kamga Mkankam, F.

    2016-11-01

    ERA-Interim product from the European Center for Medium-Range Weather Forecast (ECMWF) assimilation of African Monsoon Multidisciplinary Analysis (AMMA) resources, Meteosat satellite images, and synoptic observations were used to study local- and regional-scale environments associated with intense convective systems during the AMMA-SOP3 experiment over West Africa in the Northern Hemisphere of summer 2006. The convective system, from the 21st to 23rd of August 2006, was more active at 0000 and 1800 UTC showing diurnal cycle of deep convection over West Africa where the African easterly waves (AEWs) are developed downstream. Downstream barotropic and baroclinic energy conversions associated with strong AEWs are important for the maintenance of AEW activity in West Africa. Barotropic energy conversions dominate south of the African easterly jet (AEJ), while baroclinic energy conversions are most important north of the AEJ. From a dynamical viewpoint, the low-level vorticity presents strong positive values over the sea and Sahara zone, indicating that exists on the cyclonic shear side of the African easterly jet, which is consistent with baroclinic growth. The 925-hPa equivalent potential temperature structure show a maximum over the Sahara which corresponds to the depression observed in this region. A mosaic of three hourly infrared (IR) satellite images, depicts a very distinct signal from an initial region of convection, developing through several stages and moving off the African coast. These observations, along with those available from the World Weather Watch, provide an opportunity to carry out numerical weather prediction (NWP) studies over West Africa utilizing high resolution limited area models.

  9. Incorporating vegetation feedbacks in regional climate modeling over West Africa

    Science.gov (United States)

    Erfanian, A.; Wang, G.; Yu, M.; Ahmed, K. F.; Anyah, R. O.

    2015-12-01

    Despite major advancements in modeling of the climate system, incorporating vegetation dynamics into climate models is still at the initial stages making it an ongoing research topic. Only few of GCMs participating in CMIP5 simulations included the vegetation dynamics component. Consideration for vegetation dynamics is even less common in RCMs. In this study, RegCM4.3.4-CLM4-CN-DV, a regional climate model synchronously coupled with a land surface component that includes both Carbon-Nitrogen (CN) and Dynamic-Vegetation (DV) processes is used to simulate and project regional climate over West Africa. Due to its unique regional features, West Africa climate is known for being susceptible to land-atmosphere interactions, enhancing the importance of including vegetation dynamics in modeling climate over this region. In this study the model is integrated for two scenarios (present-day and future) using outputs from four GCMs participating in CMIP5 (MIROC, CESM, GFDL and CCSM4) as lateral boundary conditions, which form the basis of a multi-model ensemble. Results of model validation indicates that ensemble of all models outperforms each of individual models in simulating present-day temperature and precipitation. Therefore, the ensemble set is used to analyze the impact of including vegetation dynamics in the RCM on future projection of West Africa's climate. Results from the ensemble analysis will be presented, together with comparison among individual models.

  10. Fifteen Years of Annual Mass Treatment of Onchocerciasis with Ivermectin Have Not Interrupted Transmission in the West Region of Cameroon

    Directory of Open Access Journals (Sweden)

    Moses N. Katabarwa

    2013-01-01

    Full Text Available We followed up the 1996 baseline parasitological and entomological studies on onchocerciasis transmission in eleven health districts in West Region, Cameroon. Annual mass ivermectin treatment had been provided for 15 years. Follow-up assessments which took place in 2005, 2006, and 2011 consisted of skin snips for microfilariae (mf and palpation examinations for nodules. Follow-up Simulium vector dissections for larval infection rates were done from 2011 to 2012. mf prevalence in adults dropped from 68.7% to 11.4%, and nodule prevalence dropped from 65.9% to 12.1%. The decrease of mf prevalence in children from 29.2% to 8.9% was evidence that transmission was still continuing. mf rates in the follow-up assessments among adults and in children levelled out after a sharp reduction from baseline levels. Only three health districts out of 11 were close to interruption of transmission. Evidence of continuing transmission was also observed in two out of three fly collection sites that had infective rates of 0.19% and 0.18% and ATP of 70 (Foumbot and 300 (Massangam, respectively. Therefore, halting of annual mass treatment with ivermectin cannot be done after 15 years as it might escalate the risk of transmission recrudescence.

  11. Reference, Coherence and Complexity in Students' Academic Writing: Examples from Cameroon and East-Africa Corpus

    Science.gov (United States)

    Schmied, Josef; Nkemleke, Daniel

    2011-01-01

    This contribution discusses problems of students' academic writing in Africa. It sketches the wide field of English for Academic Purposes (EAP) and argues that reference, coherence and complexity are key concepts for evaluating student writing at university level. It uses material from African corpora to substantiate this claim and to illustrate…

  12. Putting farmers first: reshaping agricultural research in West Africa

    Energy Technology Data Exchange (ETDEWEB)

    Pimbert, Michel

    2012-01-15

    How agricultural research is funded, organised, controlled and practised can have a huge impact on small-scale producers in the global South. In many countries, such research is driven by external funds, priorities and technological fixes, such as hybrid seeds, which can erode crop diversity. But food producers across the world are beginning to raise their voices to ensure that agricultural research better meets their needs and priorities. A series of farmer assessments and citizens' juries in West Africa has helped farmers assess existing approaches and articulate recommendations for policy and practice to achieve their own vision of agricultural research. In 2012, a high-level policy dialogue between farmers and the Alliance for a Green Revolution in Africa hopes to take this discussion to the next level and develop a shared agenda that can serve development and the public good.

  13. Comparative financial analysis of electricity utilities in West Africa

    Energy Technology Data Exchange (ETDEWEB)

    Fritsch, Remi, E-mail: fritschr@afd.fr [Centre d' Etudes Financieres, Economiques et Bancaires (CEFEB), BP 33401, 13567 Marseille cedex 02 (France)

    2011-10-15

    Access to electricity is a major issue in West Africa. Governments have a difficult equation to solve. They naturally seek to offer their people a cheap kWh. But they are constrained by a production based largely on oil and therefore highly volatile production costs. How to fix an acceptable tariff, taking into account the investment needs required to expand the network and increase production? This analysis should provide some answers. The study presented in this paper provides a financial analysis of electricity utilities in West Africa. It allows a comparison of performances on a number of key financial ratios related to operations (Earning Before Interest Taxes Debt and Amortization/sales, working capital requirement/sales, days of receivables or payables), investment (net fixed assets/gross fixed assets), bank financing (financial structure, debt/EBITDA, interest expense/EBITDA) and economic and financial returns (Return On Capital Employed, Return On Equity). The conclusion focuses on the growth opportunity that the electricity sector could represent for each country. But this opportunity may only materialize if the EBITDA margins are restored. The available options appear limited and must be assessed taking into account the context of each country: tariff increase, improvement of technical losses or diversification into means of production no longer based primarily on oil or gas. - Highlights: > The study provides a financial analysis of electricity distribution companies in West Africa. > The study highlights generally insufficient EBITDA margins. > The study raises the question of tariffs and contribution to Gross Domestic Product of the electricity sector. > The conclusion focuses on the growth opportunity that the electricity sector could represent for each country.

  14. Risk Maps of Lassa Fever in West Africa

    OpenAIRE

    Elisabeth Fichet-Calvet; David John Rogers

    2009-01-01

    BACKGROUND: Lassa fever is caused by a viral haemorrhagic arenavirus that affects two to three million people in West Africa, causing a mortality of between 5,000 and 10,000 each year. The natural reservoir of Lassa virus is the multi-mammate rat Mastomys natalensis, which lives in houses and surrounding fields. With the aim of gaining more information to control this disease, we here carry out a spatial analysis of Lassa fever data from human cases and infected rodent hosts covering the peri...

  15. Testing Modeling Assumptions in the West Africa Ebola Outbreak

    Science.gov (United States)

    Burghardt, Keith; Verzijl, Christopher; Huang, Junming; Ingram, Matthew; Song, Binyang; Hasne, Marie-Pierre

    2016-01-01

    The Ebola virus in West Africa has infected almost 30,000 and killed over 11,000 people. Recent models of Ebola Virus Disease (EVD) have often made assumptions about how the disease spreads, such as uniform transmissibility and homogeneous mixing within a population. In this paper, we test whether these assumptions are necessarily correct, and offer simple solutions that may improve disease model accuracy. First, we use data and models of West African migration to show that EVD does not homogeneously mix, but spreads in a predictable manner. Next, we estimate the initial growth rate of EVD within country administrative divisions and find that it significantly decreases with population density. Finally, we test whether EVD strains have uniform transmissibility through a novel statistical test, and find that certain strains appear more often than expected by chance. PMID:27721505

  16. Intestinal Parasitic Infections in HIV Infected and Non-Infected Patients in a Low HIV Prevalence Region, West-Cameroon

    OpenAIRE

    2013-01-01

    The magnitude of intestinal parasitic infection in acquired immunodeficiency syndrome patients requires careful consideration in the developing world where poor nutrition is associated with poor hygiene and several tropical diseases. However, there have been very few studies addressing this issue in Cameroon. This study was conducted to determine the prevalence of intestinal parasitosis in HIV/AIDS patients in Dschang -Cameroon. Stool and blood specimens from HIV/AIDS patients and control gro...

  17. Chemistry and origin of the Mayo Kila sapphires, NW region Cameroon (Central Africa): Their possible relationship with the Cameroon volcanic line

    Science.gov (United States)

    Paul Mbih, Kemeng; Meffre, Sebastien; Yongue, Rose Fouateu; Kanouo, Nguo Sylvestre; Jay, Thomson

    2016-06-01

    Mineralogical, chemical and geochronological studies constrained the origin of sapphires from Mayo Kila, Northwest Cameroon. The sapphires are mostly blue, with sizes ranging from 2 to 5 mm. The pale blue grains are transparent, whereas, other corundums are transparent to translucent and/or opaque. The sapphires are dominantly euhedral to sub-hedral with few polished lustrous grains, acquired features during moderate to short distance transport from a proximal source rock. Solid inclusions are limited to rutile and zircon. Trace element analysis of sapphires shows significant concentration (in ppm) in some elements: Fe (2208-14,473), Ti (82-1783), Ga (77-512), Mg (0.9-264.9), Cr (b.d.l -168) and V (1.3-82). The other elements (e.g. Sn, Nb, Ta, Th, Zr, Ni, Ce) are generally below 10 ppm. The calculated ratios for some of the selected elements show an extreme variation: Fe/Mg (43-3043), Fe/Ti (2-76), Ti/Mg (1-328), and Ga/Mg (0.4-363). They are dominantly corundum crystallized in alkaline magma (s) with few from metamorphic source (s). Trace elemental features with Hf (13,354-26,238 ppm), Th (4018-45,584 ppm) and U (7825-17,175 ppm), and Th/U (0.39-2.65) found in zircon inclusions are compatible with quantified values in magmatic crystallized zircons. The Cenozoic age (mean of 30.78 ± 0.28 Ma) obtained for zircon inclusions is close to the age of some igneous rocks found within the Cameroon Volcanic Line (e.g. rocks of the Mount Oku: 31-22 Ma), showing the same period of formation. The most probable source of the zircon host sapphires is the Oku Mountain located SW of Mayo Kila.

  18. Perspectives in Genetics and Sickle Cell Disease Prevention in Africa: Beyond the Preliminary Data from Cameroon.

    Science.gov (United States)

    Wonkam, Ambroise; Ngo Bitoungui, Valentina Josiane; Ngogang, Jeanne

    2015-01-01

    Management of sickle cell disease (SCD) in Africa needs to be accompanied by various preventive strategies, including early detection via prenatal genetic diagnosis (PND). Contrary to Cameroonian doctors who considered termination of an affected pregnancy (TAP) for SCD in 36.1%, the majority of parents (62.5%) with affected children accepted TAP in principle. In practice, most women opted for TAP (90%), justified by a huge psycho-social burden. The ethical and legal challenges of PND prompted the need to explore the use of genetics for secondary prevention of SCD. In 610 Cameroonian SCD patients, the genomic variations in two principal foetal haemoglobin-promoting loci were significantly associated with foetal haemoglobin levels. In addition, the co-inheritance of a 3.7-kb α-globin gene deletion and SCD was associated with a late disease onset and possibly improved survival: there was a much higher allele frequency of the 3.7-kb α-globin gene deletion in SCD patients (∼ 40%) than in haemoglobin AA controls (∼ 10%). The data indicate the urgent need to develop and implement policy actions in sub-Saharan Africa on at least four levels: (1) the implementation of SCD screening practices and early neonatal follow-up; (2) the development and incorporating of socio-economic support to alleviate the burden of SCD on affected families; (3) the exploration of the appropriateness of the medical abortion laws for SCD, and (4) the development of national plans for genetic medicine, including research on genomic variants that affect the phenotypes of SCD, in order to potentially use them for anticipatory guidance.

  19. Challenges in meeting biomass energy needs in West Africa

    Energy Technology Data Exchange (ETDEWEB)

    Dianka, M. [GAA/RPTES, Dakar (Senegal)

    2001-07-01

    Biomass energy represents conciderable potential for West Africa. However, the traditional methods of tapping into this biomass have not only had grave consequences for the environment, but have only been able to partially resolve the crucial issue of how to sustainably supply households with domestic fuels. Nevertheless, recent progress made in the improvement of technologies enhancing biomass energy provides a glimpse at interesting perspectives fostering the modernisating and better assesment of the biocombustible and biofuel industries. Reflection conducted over these past years by a group of African experts, brought together around the ASG at the instigation of the RPTES Programme and founded on a new approach to forest resource management, illustrates the attention public powers are granting increasingly to biomass energy, which had been relegated to the back burner for so long, to the benefit of more 'conventional' energy sources. Considering the complexity of biomass energy issues, and their direct links to poverty, it is evident that isolated actions will never succeed in solving the problems currently faced. Thus it is essential to promote regional collaboration and partnerships for more effective actions and to capitalise on experiences, with the aim of ensuring sustainable development for the continent of Africa. Today, given the economic potential of more than US$6 billion generated by African forests, this implies the introduction of sustainable strategies which will result in increasing incomes and improving welfare in general. West Africa, masthead of the continent, will certainly not be an isolated case. Consequently, vigorous action supporting the sustainable management of natural resources as part of poverty alleviation programmes should be undertaken post-haste, in compliance with the Abuja Treaty establishing the African Economic Community. (au)

  20. Mapping the potential of cross-border cooperation in West Africa

    DEFF Research Database (Denmark)

    Walther, Olivier; Vollmer, Sebastian

    2015-01-01

    Mapping the socio-economic potential of border regions can provide great insights as to where cross-border co-operation could be intensified in West Africa.......Mapping the socio-economic potential of border regions can provide great insights as to where cross-border co-operation could be intensified in West Africa....

  1. Reasons for hospitalization in HIV-infected children in West Africa

    DEFF Research Database (Denmark)

    Dicko, Fatoumata; Desmonde, Sophie; Koumakpai, Sikiratou

    2014-01-01

    -infected children in West Africa (IeDEA West Africa collaboration). METHODS: We performed a six-month prospective multicentre survey from April to October 2010 in five HIV-specialized paediatric hospital wards in Ouagadougou, Accra, Cotonou, Dakar and Bamako. Baseline and follow-up data during hospitalization were...

  2. Climate drives the meningitis epidemics onset in west Africa.

    Directory of Open Access Journals (Sweden)

    Benjamin Sultan

    2005-01-01

    Full Text Available BACKGROUND: Every year West African countries within the Sahelo-Sudanian band are afflicted with major meningococcal meningitis (MCM disease outbreaks, which affect up to 200,000 people, mainly young children, in one of the world's poorest regions. The timing of the epidemic year, which starts in February and ends in late May, and the spatial distribution of disease cases throughout the "Meningitis Belt" strongly indicate a close linkage between the life cycle of the causative agent of MCM and climate variability. However, mechanisms responsible for the observed patterns are still not clearly identified. METHODS AND FINDINGS: By comparing the information on cases and deaths of MCM from World Health Organization weekly reports with atmospheric datasets, we quantified the relationship between the seasonal occurrence of MCM in Mali, a West African country, and large-scale atmospheric circulation. Regional atmospheric indexes based on surface wind speed show a clear link between population dynamics of the disease and climate: the onset of epidemics and the winter maximum defined by the atmospheric index share the same mean week (sixth week of the year; standard deviation, 2 wk and are highly correlated. CONCLUSIONS: This study is the first that provides a clear, quantitative demonstration of the connections that exist between MCM epidemics and regional climate variability in Africa. Moreover, this statistically robust explanation of the MCM dynamics enables the development of an Early Warning Index for meningitis epidemic onset in West Africa. The development of such an index will undoubtedly help nationwide and international public health institutions and policy makers to better control MCM disease within the so-called westward-eastward pan-African Meningitis Belt.

  3. Impacts of drought and responses of rural populations in West Africa: a systematic review

    OpenAIRE

    Gautier, Denis; Denis, David; Locatelli, Bruno

    2016-01-01

    International audience; In West Africa, climate variations and droughts have always affected livelihoods but have also triggered adaptation strategies. A better understanding of the impacts of drought and the responses of West African populations is indispensable for researchers and decision makers in the current and future context of multiple socioeconomic and environmental changes, including climate change. We conducted a systematic review of the literature on drought in West Africa. In thi...

  4. Declining incidence of malaria imported into the UK from West Africa

    Directory of Open Access Journals (Sweden)

    Smith Valerie

    2008-11-01

    Full Text Available Abstract Background Two thirds of all falciparum malaria cases reported in the United Kingdom (UK are acquired in West Africa (WA. To ensure recommendations and guidelines for malaria prophylaxis in travellers to West Africa correlate to the risk of infection, a study was undertaken to examine recent trends and predict future patterns of imported malaria acquired by UK residents visiting West Africa and West African visitors to the UK between 1993 and 2006. Methods and Results Using passenger numbers and malaria surveillance reports, the data revealed a 2.3-fold increase in travel to West Africa with a five-fold increase in travelers visiting friends and relatives (VFR. Malaria incidence fell through the study period, the greatest decline noted in VFR with a fall from 196 cases/1,000 person-years to 52 cases/1,000 person-years, 9.8% per year p Discussion The reduction in incidence among all three groups of travellers may be explained by several factors; changing chemoprophylaxis usage and/or increased travel in urban areas where malaria risk has declined over the past decade, or widespread reduction in malaria transmission in West Africa. Conclusion With the reduction in malaria incidence seen in both visitors to and from West Africa, the most rational explanation for these findings is a fall in malaria transmission in West Africa, which may require a change in chemoprophylaxis policy for UK travelers over the next 5–10 years.

  5. Geostatistical model-based estimates of Schistosomiasis prevalence among individuals aged ≤ 20 years in West Africa.

    Directory of Open Access Journals (Sweden)

    Nadine Schur

    2011-06-01

    Full Text Available BACKGROUND: Schistosomiasis is a water-based disease that is believed to affect over 200 million people with an estimated 97% of the infections concentrated in Africa. However, these statistics are largely based on population re-adjusted data originally published by Utroska and colleagues more than 20 years ago. Hence, these estimates are outdated due to large-scale preventive chemotherapy programs, improved sanitation, water resources development and management, among other reasons. For planning, coordination, and evaluation of control activities, it is essential to possess reliable schistosomiasis prevalence maps. METHODOLOGY: We analyzed survey data compiled on a newly established open-access global neglected tropical diseases database (i to create smooth empirical prevalence maps for Schistosoma mansoni and S. haematobium for individuals aged ≤ 20 years in West Africa, including Cameroon, and (ii to derive country-specific prevalence estimates. We used Bayesian geostatistical models based on environmental predictors to take into account potential clustering due to common spatially structured exposures. Prediction at unobserved locations was facilitated by joint kriging. PRINCIPAL FINDINGS: Our models revealed that 50.8 million individuals aged ≤ 20 years in West Africa are infected with either S. mansoni, or S. haematobium, or both species concurrently. The country prevalence estimates ranged between 0.5% (The Gambia and 37.1% (Liberia for S. mansoni, and between 17.6% (The Gambia and 51.6% (Sierra Leone for S. haematobium. We observed that the combined prevalence for both schistosome species is two-fold lower in Gambia than previously reported, while we found an almost two-fold higher estimate for Liberia (58.3% than reported before (30.0%. Our predictions are likely to overestimate overall country prevalence, since modeling was based on children and adolescents up to the age of 20 years who are at highest risk of infection. CONCLUSION

  6. Application of Non-Thermal Plasma to the Treatment of Effluent Discharged Into River Choumlou in Bafoussam, West Cameroon

    Directory of Open Access Journals (Sweden)

    Estella T. Njoyim

    2016-07-01

    Full Text Available Most rivers in urban areas of developing countries are the of effluents discharged from industries. This is the case of River Choumlou (in Bafoussam-West Region, Cameroon which receives all discharges from “Brasseries du Cameroun”, Bafoussam branch. The objective of this work was to determine the level of organic contaminants in water samples and to treat the polluted samples using the non-thermal gliding arc plasma. Nonthermal plasma consists of charged particles, radicals and excited molecules. The aim was to show the interest of such a process for cleaning up of surface waters (real effluent and to cope with the protection of our environment. Due to the fact that pollution of streams and rivers from the discharge of sewage and industrial wastes poses a major problem to the environment, the researchers were particularly interested in investigating the oxidizing and acidifying properties of non-thermal plasma on polluted surface water. Samples were collected upstream and downstream from the brewery’s effluent outlet. Samples taken at the point R1 (downstream were first analyzed by volumetric and instrumental methods in order to determine the organoleptic, physico-chemical and organic parameters. These samples were then exposed to the gliding discharge in humid air for a time period of between 3-30 minutes. After 30 minutes of exposure, a decrease in turbidity (24.09%, BOD5 (44.93% and COD (48.92% were observed resulting in transparency apparition; with a decrease in pH (7.9 to 3 due to the formation of acidifying species in solution. These results reflect a considerable reduction in the pollution load of the water collected at R1. This work shows that the effectiveness of the Gliding Arc in wastewater treatment is attributed to the oxidizing power of the hydroxyl radical and acidifying power of the nitrogen monoxide radical formed in the plasma. Despite the low rate of reduction of COD and BOD5 in 30 min, it can be said that the plasma

  7. Ebola in West Africa:an international medical emergency

    Institute of Scientific and Technical Information of China (English)

    Yasir Waheed

    2014-01-01

    West Africa is facing the worst Ebola outbreak with 3 685 cases and 1 841 deaths reported from Liberia, Guinea, Senegal, Sierra Leona and Nigeria. There is no vaccine or direct treatment available to treat the patients with Ebola. World Health Organization (WHO) has approved the use of experimental drugs for Ebola patients. Health workers are at high risk. The governments and WHO are responsible to provide necessary protective equipment to health workers dealing with Ebola. There is a strong need to identify the invisible chains of virus transmission. World Bank pledges$200 million to fight against Ebola, while WHO said$430 million are needed to control the Ebola outbreak. Ebola can be contained by early detection and isolation of case, contact tracing, monitoring of contacts and adaptation of rigorous procedures for virus control.

  8. Ebola in West Africa:an international medical emergency

    Institute of Scientific and Technical Information of China (English)

    Yasir; Waheed

    2014-01-01

    West Africa is facing the worst Ebola outbreak with 3685 cases and 1841 deaths reported from Liberia,Cuinea,Senegal,Sierra Leona and Nigeria.There is no vaccine or direct treatment available to treat the patients with Ebola.World Health Organization(WHO) has approved the use of experimental drugs for Ebola patients.Health workers are at high risk.The governments and WHO are responsible to provide necessary protective equipment to health workers dealing with Ebola.There is a strong need to identify the invisible chains of virus transmission.World Bank pledges $200 million to fight against Ebola,while WHO said $430 million are needed to control the Ebola outbreak.Ebola can be contained by early detection and isolation of case,contact tracing,monitoring of contacts and adaptation of rigorous procedures for virus control.

  9. Remote sensing needs and capabilities in West Africa

    Institute of Scientific and Technical Information of China (English)

    Edward M.Osei,Jr.

    2004-01-01

    The greatest advantage of remote sensing over conventional measurements lies in the opportunity to carry out detailed spatio-temporal analysis of land and ocean features on a very frequent basis. This paper analyses the contribution of satellite imagery to atmospheric, geophysical and ocean studies and management in West Africa since the early 1980s.The detailed application of data from optical sensors (e.g. Meteosat,NOAA/AVHRR, SPOT,L andsat TM, etc.) for weather prediction, hydrogeological, landuse/cover and cartographic studies has been acknowledged. However, the use of microwave (e.g. SAR) and optical data for ocean monitoring and studies in the sub-region is still very limited. Even though sufficient remote sensing expertise and infrastructure is perceived in the region, no clearly defined networking or database exists.

  10. Atlantic forcing of persistent drought in West Africa.

    Science.gov (United States)

    Shanahan, T M; Overpeck, J T; Anchukaitis, K J; Beck, J W; Cole, J E; Dettman, D L; Peck, J A; Scholz, C A; King, J W

    2009-04-17

    Although persistent drought in West Africa is well documented from the instrumental record and has been primarily attributed to changing Atlantic sea surface temperatures, little is known about the length, severity, and origin of drought before the 20th century. We combined geomorphic, isotopic, and geochemical evidence from the sediments of Lake Bosumtwi, Ghana, to reconstruct natural variability in the African monsoon over the past three millennia. We find that intervals of severe drought lasting for periods ranging from decades to centuries are characteristic of the monsoon and are linked to natural variations in Atlantic temperatures. Thus the severe drought of recent decades is not anomalous in the context of the past three millennia, indicating that the monsoon is capable of longer and more severe future droughts.

  11. Regional Model Nesting Within GFS Daily Forecasts Over West Africa

    Science.gov (United States)

    Druyan, Leonard M.; Fulakeza, Matthew; Lonergan, Patrick; Worrell, Ruben

    2010-01-01

    The study uses the RM3, the regional climate model at the Center for Climate Systems Research of Columbia University and the NASA/Goddard Institute for Space Studies (CCSR/GISS). The paper evaluates 30 48-hour RM3 weather forecasts over West Africa during September 2006 made on a 0.5 grid nested within 1 Global Forecast System (GFS) global forecasts. September 2006 was the Special Observing Period #3 of the African Monsoon Multidisciplinary Analysis (AMMA). Archived GFS initial conditions and lateral boundary conditions for the simulations from the US National Weather Service, National Oceanographic and Atmospheric Administration were interpolated four times daily. Results for precipitation forecasts are validated against Tropical Rainfall Measurement Mission (TRMM) satellite estimates and data from the Famine Early Warning System (FEWS), which includes rain gauge measurements, and forecasts of circulation are compared to reanalysis 2. Performance statistics for the precipitation forecasts include bias, root-mean-square errors and spatial correlation coefficients. The nested regional model forecasts are compared to GFS forecasts to gauge whether nesting provides additional realistic information. They are also compared to RM3 simulations driven by reanalysis 2, representing high potential skill forecasts, to gauge the sensitivity of results to lateral boundary conditions. Nested RM3/GFS forecasts generate excessive moisture advection toward West Africa, which in turn causes prodigious amounts of model precipitation. This problem is corrected by empirical adjustments in the preparation of lateral boundary conditions and initial conditions. The resulting modified simulations improve on the GFS precipitation forecasts, achieving time-space correlations with TRMM of 0.77 on the first day and 0.63 on the second day. One realtime RM3/GFS precipitation forecast made at and posted by the African Centre of Meteorological Application for Development (ACMAD) in Niamey, Niger

  12. A Regional Model Study of Synoptic Features Over West Africa

    Science.gov (United States)

    Druyan, Leonard M.; Fulakeza, Matthew; Lonergan, Patrick; Saloum, Mahaman; Hansen, James E. (Technical Monitor)

    2001-01-01

    Synoptic weather features over West Africa were studied in simulations by the regional simulation model (RM) at the NASA/Goddard Institute for Space Studies. These pioneering simulations represent the beginning of an effort to adapt regional models for weather and climate prediction over West Africa. The RM uses a cartesian grid with 50 km horizontal resolution and fifteen vertical levels. An ensemble of four simulations was forced with lateral boundary conditions from ECMWF global analyses for the period 8-22 August 1988. The simulated mid-tropospheric circulation includes the skillful development and movement of several African wave disturbances. Wavelet analysis of mid-tropospheric winds detected a dominant periodicity of about 4 days and a secondary periodicity of 5-8 days. Spatial distributions of RM precipitation and precipitation time series were validated against daily rain gauge measurements and ISCCP satellite infrared cloud imagery. The time-space distribution of simulated precipitation was made more realistic by combining the ECMWR initial conditions with a 24-hr spin-up of the moisture field and also by damping high frequency gravity waves by dynamic initialization. Model precipitation "forecasts" over the Central Sahel were correlated with observations for about three days, but reinitializing with observed data on day 5 resulted in a dramatic improvement in the precipitation validation over the remaining 9 days. Results imply that information via the lateral boundary conditions is not always sufficient to minimize departures between simulated and actual precipitation patterns for more than several days. In addition, there was some evidence that the new initialization may increase the simulations' sensitivity to the quality of lateral boundary conditions.

  13. Ebola outbreak in West Africa: a neglected tropical disease

    Directory of Open Access Journals (Sweden)

    Alcides Troncoso

    2015-04-01

    Full Text Available Neglected tropical diseases (NTDs are remediable injustices of our times. Poverty is the starting point, and the ultimate outcome, of NTD. Ebola is just one of many NTDs that badly need attention. Ebola exacerbates West Africa's poverty crisis. The virus spreading in Guinea, Liberia and Sierra Leone has led to food shortages and neglect of other devastating tropical illnesses. A health crisis that was ignored for months until it was out of control is now beginning to get the attention required, if not the resources. So far, the world´s nations have contributed far less than the $ 1 billion. The U.N. estimates would need to control the epidemic before it becomes endemic. Past outbreaks of Ebola have flared up in remote, forested communities, disconnected from much of the outside world. But the outbreak in West Africa has not slowed yet, and it worsens there the chances of it spreading to other countries. Ebola draws attention to NTD. Ebola is not only a health emergency, but also it´s a poverty crisis. The current Global Ebola crisis presents a multitude of challenges in terms of our capacity to respond; the future is even less predictable. Ebola outbreak represents inequity in health as the occurrence of health differences considered unnecessary, avoidable, unfair, and unjust, thus adding a moral and ethical dimension to health inequalities. Health equity does not refer only to the fairness in the distribution of health or the provision of health care; rather, it is linked with the larger issues of fairness and justice in social arrangements.

  14. Crisis and neoliberal reforms in Africa : civil society and agro-industry in anglophone Cameroon's plantation economy

    NARCIS (Netherlands)

    Konings, P.J.J.

    2011-01-01

    This book discusses the consequences of the economic and financial crisis that befell the Cameroonian agro-industrial sector in the 1980s, using as a case study the plantation economy of the anglophone region of Cameroon. Two agro-industrial enterprises have dominated the plantation sector: a huge p

  15. Serosurveillance of Viral Pathogens Circulating in West Africa

    Science.gov (United States)

    2016-05-20

    ONNV in nearby Cameroon where approximately 47% of healthy adults 287 tested positive for CHIKV and/or ONNV (with noted overlap) (32). Our longitudinal...factors in their lifestyle , 305 geographic location, or workplace environment. Overall, our results indicate that in addition to 306 LASV, there is a

  16. Desertification, refugees and regional conflict in west Africa.

    Science.gov (United States)

    Nnoli, O

    1990-06-01

    This article documents the potential for inter-state conflict in the migration of hundreds of thousands of famine refugees across international borders in West Africa. Nigeria and Ghana, for example, have to deal not only with the effects of land degradation in their northern territories but also with the influx of famine victims from Mali, Niger, Chad and Burkino Faso. These migrations put an enormous extra burden on the fragile and already overstretched social and economic infrastructures of the host countries. The construction of dams for irrigation and electricity generation in international river basins, is another cause of inter-state conflict related to land degradation. The capacity of West African states to find peaceful solutions to these problems is being undermined by the increasing impoverishment and marginalisation of their populations. A self-serving neo-colonialist governing elite is caught in the economic stranglehold of the advanced capitalist nations. While there is thus no short term solution to the problem of land degradation, immediate steps should at least be taken to give legal protection to those who are forced to cross international borders because of drought and famine.

  17. An interventional model to develop health professionals in West Africa.

    Science.gov (United States)

    Sanou, Anselme Simeon; Awoyale, Florence Adeola; Diallo, Abdoulaye

    2014-01-01

    The health sector is characterized by a human resource base lacking in numbers, specialized skills, and management skills. West African Health Organization (WAHO) recognizes the need within the West Africa sub-region for bilingual professionals who are skilled in public health, management, leadership, and information technology to build human capacity in public health and developed the Young Professionals Internship Program (YPIP). Our study explores the evolution of the programme. YPIP program has successfully carried out its original aims and objectives to equip young professionals with basic principles of public health, management, and leadership, acquire competence in a second official language (French, English, and Portuguese), information and communication technology. Contributing factors towards this successful evaluation included positive ratings and commentary from previous interns about the relevance, usefulness, and quality of the programme, encouraging feedback from WAHO management, trainers, administrators, and intern employers on the impact of the YPIP program on young professionals, supporting evidence that demonstrates increased knowledge in professional skills and language competency.

  18. Maintenance Support of a Field Station in Sierra Leone, West Africa

    Science.gov (United States)

    1994-03-04

    AD-A279 136 ARMY PROJECT ORDER NO: 91PP1801 TITLE: MAINTENANCE SUPPORT OF A FIELD STATION IN SIERRA LEONE , WEST AFRICA PRINCIPAL INVESTIGATOR: Brian...SUBTITLE S. FUNDING NUMBERS Maintenance Support of a Field Station in Army Project Order Sierra Leone , West Africa 91PP1801 6. AUTHOR(S) Brian W.J. Mahy...Detrick Frederick, Maryland 21702-5012 11. SUPPLEMENTARY NOTES Subtitle: Maintenance Support of a FiLd Station in Sierra Leone , West Africa for Lassa

  19. Genetics, Morphology, Advertisement Calls, and Historical Records Distinguish Six New Polyploid Species of African Clawed Frog (Xenopus, Pipidae) from West and Central Africa.

    Science.gov (United States)

    Evans, Ben J; Carter, Timothy F; Greenbaum, Eli; Gvoždík, Václav; Kelley, Darcy B; McLaughlin, Patrick J; Pauwels, Olivier S G; Portik, Daniel M; Stanley, Edward L; Tinsley, Richard C; Tobias, Martha L; Blackburn, David C

    2015-01-01

    African clawed frogs, genus Xenopus, are extraordinary among vertebrates in the diversity of their polyploid species and the high number of independent polyploidization events that occurred during their diversification. Here we update current understanding of the evolutionary history of this group and describe six new species from west and central sub-Saharan Africa, including four tetraploids and two dodecaploids. We provide information on molecular variation, morphology, karyotypes, vocalizations, and estimated geographic ranges, which support the distinctiveness of these new species. We resurrect Xenopus calcaratus from synonymy of Xenopus tropicalis and refer populations from Bioko Island and coastal Cameroon (near Mt. Cameroon) to this species. To facilitate comparisons to the new species, we also provide comments on the type specimens, morphology, and distributions of X. epitropicalis, X. tropicalis, and X. fraseri. This includes significantly restricted application of the names X. fraseri and X. epitropicalis, the first of which we argue is known definitively only from type specimens and possibly one other specimen. Inferring the evolutionary histories of these new species allows refinement of species groups within Xenopus and leads to our recognition of two subgenera (Xenopus and Silurana) and three species groups within the subgenus Xenopus (amieti, laevis, and muelleri species groups).

  20. 77 FR 74265 - In the Matter of the Designation of Movement for Unity and Jihad in West Africa; Also Known as...

    Science.gov (United States)

    2012-12-13

    ... Matter of the Designation of Movement for Unity and Jihad in West Africa; Also Known as Movement for Oneness and Jihad in West Africa; Also Known as Unity Movement for Jihad in West Africa; Also Known as Jamat Tawhid Wal Jihad Fi Garbi Afriqqiya; Also Known as Tawhid Wal Jihad in West Africa; Also Known...

  1. West Nile Disease Epidemiology in North-West Africa: Bibliographical Review.

    Science.gov (United States)

    Benjelloun, A; El Harrak, M; Belkadi, B

    2016-12-01

    West Nile fever (WNF) or West Nile disease (WND) is a mosquito-borne viral disease that can affect birds, humans and horses. West Nile virus (WNV) is a member of the genus Flavivirus in the family Flaviviridae. WNV is maintained in a mosquito-bird-mosquito transmission cycle, whereas humans and horses are considered dead-end hosts. In human and horses, symptoms range from unapparent infection to mild febrile illness, meningitis, encephalitis or death. WNV has a wide geographical range that includes portions of Europe, Asia, Africa, Australia (Kunjin virus), and in North, Central and South America. Migratory birds are thought to be primarily responsible for virus dispersal, including reintroduction of WNV from endemic areas into regions that experience sporadic outbreaks (Fields Virology, 2001, Lippincott Williams and Wilkins, Philadelphia, Pennsylvania, USA, 1043-1125). The occurrence of disease in humans and animals along with birds and mosquitoes surveillance for WNV activity demonstrates that the virus range has dramatically expanded including North, Central and South America as well as Europe and countries facing the Mediterranean Basin. WND infection in humans has been reported in Morocco in 1996 (Virologie, 1, 1997, 248), in Tunisia in 2007 (Ann. N. Y. Acad., 951, 2001, 117) (Med. Trop., 61, 2001, 487) and 2003 (Epidémiologie de la fièvre West Nile, 2012, Thèse de doctorat, Université Montpellier II, Sciences et techniques du Langueduc, Montpellier, France), and in Algeria in 1994 (Rev. Sci. Tech., 31, 2012, 829). Outbreaks of equine encephalitis have been also reported in Morocco in 1996 (Bull. OIE, 11, 1996, 867), in 2003 (Emerg. Infect. Dis., 11, 2005, 306) and in 2010 (World Animal Health Information Database. WAHID, 2010). Serological evidence of WNV has been demonstrated in the three countries in many species. The aim of this review was to assess the epidemiological situation of WND in north-west Africa comprising Morocco, Algeria and Tunisia, with

  2. Molecular Surveillance Identifies Multiple Transmissions of Typhoid in West Africa

    Science.gov (United States)

    Wong, Vanessa K.; Holt, Kathryn E.; Okoro, Chinyere; Baker, Stephen; Pickard, Derek J.; Marks, Florian; Page, Andrew J.; Olanipekun, Grace; Munir, Huda; Alter, Roxanne; Fey, Paul D.; Feasey, Nicholas A.; Weill, Francois-Xavier; Le Hello, Simon; Hart, Peter J.; Kariuki, Samuel; Breiman, Robert F.; Gordon, Melita A.; Heyderman, Robert S.; Jacobs, Jan; Lunguya, Octavie; Msefula, Chisomo; MacLennan, Calman A.; Keddy, Karen H.; Smith, Anthony M.; Onsare, Robert S.; De Pinna, Elizabeth; Nair, Satheesh; Amos, Ben; Dougan, Gordon; Obaro, Stephen

    2016-01-01

    Background The burden of typhoid in sub-Saharan African (SSA) countries has been difficult to estimate, in part, due to suboptimal laboratory diagnostics. However, surveillance blood cultures at two sites in Nigeria have identified typhoid associated with Salmonella enterica serovar Typhi (S. Typhi) as an important cause of bacteremia in children. Methods A total of 128 S. Typhi isolates from these studies in Nigeria were whole-genome sequenced, and the resulting data was used to place these Nigerian isolates into a worldwide context based on their phylogeny and carriage of molecular determinants of antibiotic resistance. Results Several distinct S. Typhi genotypes were identified in Nigeria that were related to other clusters of S. Typhi isolates from north, west and central regions of Africa. The rapidly expanding S. Typhi clade 4.3.1 (H58) previously associated with multiple antimicrobial resistances in Asia and in east, central and southern Africa, was not detected in this study. However, antimicrobial resistance was common amongst the Nigerian isolates and was associated with several plasmids, including the IncHI1 plasmid commonly associated with S. Typhi. Conclusions These data indicate that typhoid in Nigeria was established through multiple independent introductions into the country, with evidence of regional spread. MDR typhoid appears to be evolving independently of the haplotype H58 found in other typhoid endemic countries. This study highlights an urgent need for routine surveillance to monitor the epidemiology of typhoid and evolution of antimicrobial resistance within the bacterial population as a means to facilitate public health interventions to reduce the substantial morbidity and mortality of typhoid. PMID:27657909

  3. Child fostering in West Africa: New perspectives on theory and practices

    NARCIS (Netherlands)

    Alber, E.; Martin, J.; Notermans, C.D.

    2013-01-01

    Introduction / Erdmute Alber, Jeannett Martin and Catrien Notermans -- A framework for the analysis of parent roles / Esther Goody -- Adoption, fosterage and marriage / Suzanne Lallemand -- The transfer of belonging: theories on child fostering in West Africa reviewed / Erdmute Alber -- Experiencing

  4. Bacillus anthracis Diversity and Geographic Potential across Nigeria, Cameroon and Chad: Further Support of a Novel West African Lineage

    OpenAIRE

    2015-01-01

    Zoonoses, diseases affecting both humans and animals, can exert tremendous pressures on human and veterinary health systems, particularly in resource limited countries. Anthrax is one such zoonosis of concern and is a disease requiring greater public health attention in Nigeria. Here we describe the genetic diversity of Bacillus anthracis in Nigeria and compare it to Chad, Cameroon and a broader global dataset based on the multiple locus variable number tandem repeat (MLVA-25) genetic typing ...

  5. Ebola outbreak in West Africa: a neglected tropical disease

    Institute of Scientific and Technical Information of China (English)

    Alcides; Troncoso

    2015-01-01

    Neglected tropical diseases(NTDs) are remediable injustices of our times. Poverty is the starting point, and the ultimate outcome, of NTD. Ebola is just one of many NTDs that badly need attention. Ebola exacerbates West Africa’s poverty crisis. The virus spreading in Guinea,Liberia and Sierra Leone has led to food shortages and neglect of other devastating tropical illnesses. A health crisis that was ignored for months until it was out of control is now beginning to get the attention required, if not the resources. So far, the world′s nations have contributed far less than the $ 1 billion. The U.N. estimates would need to control the epidemic before it becomes endemic. Past outbreaks of Ebola have flared up in remote, forested communities, disconnected from much of the outside world. But the outbreak in West Africa has not slowed yet, and it worsens there the chances of it spreading to other countries. Ebola draws attention to NTD. Ebola is not only a health emergency, but also it′s a poverty crisis.The current Global Ebola crisis presents a multitude of challenges in terms of our capacity to respond; the future is even less predictable. Ebola outbreak represents inequity in health as the occurrence of health differences considered unnecessary, avoidable, unfair, and unjust, thus adding a moral and ethical dimension to health inequalities. Health equity does not refer only to the fairness in the distribution of health or the provision of health care; rather, it is linked with the larger issues of fairness and justice in social arrangements.

  6. The Impact of Vulnerability and Resilience to Environmental Changes on Mobility Patterns in West Africa

    OpenAIRE

    Zickgraf, Caroline; Vigil Diaz Telenti, Sara; De Longueville, Florence; Ozer, Pierre; Gemenne, François

    2016-01-01

    From the Sahel to the coast, West Africa is experiencing a variety of climate change impacts, including sea level rise, soil salinization, floods, drought, and desertification, while simultaneously suffering from other forms of environmental degradation. Together, these environmental changes are significantly influencing migration patterns in and out of West Africa. This paper seeks to analyze vulnerability and resilience to environmental changes as they affect and are affected by mobility pa...

  7. The possible role of local air pollution in climate change in West Africa

    OpenAIRE

    Knippertz, P; Evans, MJ; Field, PR; Fink, AH; C. Liousse; Marsham, JH

    2015-01-01

    The climate of West Africa is characterized by a sensitive monsoon system that is associated with marked natural precipitation variability. This region has been and is projected to be subject to substantial global and regional-scale changes including greenhouse-gas-induced warming and sea-level rise, land-use and land-cover change, and substantial biomass burning. We argue that more attention should be paid to rapidly increasing air pollution over the explosively growing cities of West Africa...

  8. An empirical analysis of the Ebola outbreak in West Africa

    CERN Document Server

    Khaleque, Abdul

    2016-01-01

    The data for the Ebola outbreak that occurred in 2014-2016 in three countries of West Africa are analysed within a common framework. The analysis is made using the results of an agent based Susceptible-Infected-Removed (SIR) model on a Euclidean network, where nodes at a distance $l$ are connected with probability $P(l) \\propto l^{-\\delta }$ in addition to nearest neighbors. The cumulative density of infected population here has the form $R(t) = \\frac{a\\exp(t/T)}{1+c\\exp(t/T)}$, where the parameters depend on $\\delta$ and the infection probability $q$. This form is seen to fit well with the data. Using the best fitting parameters, the time at which the peak is reached is estimated and is shown to be consistent with the data. We also show that in the Euclidean model, one can choose $\\delta$ and $q$ values which reproduce the data for the three countries qualitatively. These choices are correlated with population density, control schemes and other factors.

  9. An empirical analysis of the Ebola outbreak in West Africa

    Science.gov (United States)

    Khaleque, Abdul; Sen, Parongama

    2017-02-01

    The data for the Ebola outbreak that occurred in 2014–2016 in three countries of West Africa are analysed within a common framework. The analysis is made using the results of an agent based Susceptible-Infected-Removed (SIR) model on a Euclidean network, where nodes at a distance l are connected with probability P(l) ∝ l‑δ, δ determining the range of the interaction, in addition to nearest neighbors. The cumulative (total) density of infected population here has the form , where the parameters depend on δ and the infection probability q. This form is seen to fit well with the data. Using the best fitting parameters, the time at which the peak is reached is estimated and is shown to be consistent with the data. We also show that in the Euclidean model, one can choose δ and q values which reproduce the data for the three countries qualitatively. These choices are correlated with population density, control schemes and other factors. Comparing the real data and the results from the model one can also estimate the size of the actual population susceptible to the disease. Rescaling the real data a reasonably good quantitative agreement with the simulation results is obtained.

  10. Mites associated with stored grain commodities in Benin, West Africa.

    Science.gov (United States)

    Zannou, Ignace D; Adebo, Habib O; Zannou, Elisabeth; Hell, Kerstin

    2013-12-01

    After insects, mites are the major arthropod pests that inhabit stored agricultural products worldwide. To determine the acarofauna that infests cowpea, maize, paddy rice and sorghum in Benin (West Africa), surveys were conducted in some principal markets (Dantokpa, Glazoue and Parakou) of this country. A total of 555 samples of grains and debris were collected in May and September 2011. More than 56 species belonging to 24 mite families were recorded in the four products. These mite species included predators, parasites, fungivorous, phytophagous and other groups whose feeding habits are not well known. The family Cheyletidae was the most prevalent and the most diverse predatory mite family encountered, in which Cheyletus malaccensis Oudemans was the most abundant species. Several families of mite pests and mites responsible for allergies (Acaridae, Glycyphagidae, Pyroglyphidae, Pyemotidae and Saproglyphidae) were also detected. The three most dominant and frequent species were C. malaccensis, Suidasia nesbitti (Hughes) and Suidasia sp. Statistical analysis showed that densities of these three mite species were higher in Parakou than in Glazoue and Dantokpa, on one hand, and higher in debris than in grains, on the other hand. The densities of S. nesbitti and Suidasia sp. decreased significantly during the dry season, whereas C. malaccensis remained stable throughout the two samplings. Of all grains, sorghum was the least infested with mites. This study shows that in Benin mites are present in stored agricultural products to which they cause serious damage, and may cause various allergies to people.

  11. Multi-level governance and adaptive capacity in West Africa

    Directory of Open Access Journals (Sweden)

    Maria Brockhaus

    2012-08-01

    Full Text Available In most regions in West Africa, livelihoods depend heavily on forest ecosystem goods and services, often in interplay with agricultural and livestock production systems. Numerous drivers of change are creating a range of fundamental economic, ecological, social and political challenges for the governance of forest commons. Climate change and its impacts on countries’ and regions’ development add a new dimension to an already challenging situation. Governance systems are challenged to set a frame for formulating, financing and implementing adaptation strategies at multiple layers, often in a context of ongoing institutional changes such as decentralisation. A deeper understanding of actors, institutions and networks is needed to overcome barriers in socio-ecological systems to adaptation and enable or enhance adaptive capacity. In this paper, we explore the relationship between governance and adaptive capacity, and characterise and assess the effects of a set of variables and indicators related to two core variables: Institutional flexibility, and individual and organisational understandings and perceptions. We present a comparative analysis with multiple methods based on a number of case studies undertaken at different levels in Burkina Faso and Mali. One of the key findings indicates the importance and influence of discourses and narratives, and how they affect adaptive capacity at different levels. Revealing the ideological character of discourses can help to enable adaptive capacity, as it would break the influence of the actors that employ these narratives to pursuit their own interests.

  12. Data Integration for Climate Vulnerability Mapping in West Africa

    Directory of Open Access Journals (Sweden)

    Alex de Sherbinin

    2015-11-01

    Full Text Available Vulnerability mapping reveals areas that are likely to be at greater risk of climate-related disasters in the future. Through integration of climate, biophysical, and socioeconomic data in an overall vulnerability framework, so-called “hotspots” of vulnerability can be identified. These maps can be used as an aid to targeting adaptation and disaster risk management interventions. This paper reviews vulnerability mapping efforts in West Africa conducted under the USAID-funded African and Latin American Resilience to Climate Change (ARCC project. The focus is on the integration of remotely sensed and socioeconomic data. Data inputs included a range of sensor data (e.g., MODIS NDVI, Landsat, SRTM elevation, DMSP-OLS night-time lights as well as high-resolution poverty, conflict, and infrastructure data. Two basic methods were used, one in which each layer was transformed into standardized indicators in an additive approach, and another in which remote sensing data were used to contextualize the results of composite indicators. We assess the benefits and challenges of data integration, and the lessons learned from these mapping exercises.

  13. Precipitation chemistry and wet deposition in a remote wet savanna site in West Africa: Djougou (Benin)

    Science.gov (United States)

    Akpo, A. B.; Galy-Lacaux, C.; Laouali, D.; Delon, C.; Liousse, C.; Adon, M.; Gardrat, E.; Mariscal, A.; Darakpa, C.

    2015-08-01

    , biomass burning and biofuel combustions. The second highest contribution is the calcium ion (13.3 μeq·L-1), characteristic of dust aerosols from terrigenous sources, Calcium contributes up to 46% of the precipitation chemistry in Djougou. Finally, these results are compared to those obtained for other selected African sites representative of other main natural ecosystems: dry savanna and forest. The study of the African ecosystem transect indicates a pH gradient with more acidic pH in the forested ecosystem. Nitrogenous contribution to the chemical composition of rain in Lamto, wet savanna, (24%) is equivalent to the one estimated in Djougou (24%). The last contribution concerns organic acidity, which represents 7% of total ionic content of precipitation at Djougou. The relative particulate contribution PC and the relative gaseous contribution GC are calculated using the mean chemical composition measured in Djougou for the studied period. The comparison with other African sites gives 40% and 43% PC in wet savannas of Lamto (Côte d'Ivoire) and Djougou (Benin) respectively, 20% PC in the equatorial forest of Zoetele (Cameroon) and 80% PC in dry savanna of Banizoumbou (Niger). The results shown here indicate the existence of a North-South gradients of organic, marine, terrigenous and nitrogenous contributions along the transect in West and Central Africa.

  14. Qur'anic and "Ajami" Literacies in Pre-Colonial West Africa

    Science.gov (United States)

    Diallo, Ibrahima

    2012-01-01

    Traditional African literacy practices have often been ignored in the wake of European colonialism and the educational policies of colonial governments. Nonetheless, literacy had been established in parts of Africa following the introduction of Islam. This paper will examine the developments of literacy in pre-colonial West Africa. In this region,…

  15. International trends in health science librarianship part 15: West Africa (Ghana, Nigeria, Senegal).

    Science.gov (United States)

    Sulemani, Solomon Bayugo; Afarikumah, Ebenezer; Aggrey, Samuel Bentil; Ajuwon, Grace A; Diallo, Ousmane

    2015-09-01

    This is the 15th in a series of articles exploring international trends in health science librarianship in the 21st century. It is the third of four articles pertaining to different regions in the African continent. The present issue focuses on countries in West Africa (Ghana, Nigeria and Senegal). The next feature column will investigate trends in North Africa. JM.

  16. Modelling the impacts of deforestation on monsoon rainfall in West Africa

    Energy Technology Data Exchange (ETDEWEB)

    Abiodun, B J [Department of Environmental and Geographical Science, University of Cape Town (South Africa); Pal, J S [Department of Civil Engineering and Environmental Science, Loyola Marymount University, California (United States); Afiesimama, E A [WMO Regional Research and Training Institute, Lagos (Nigeria); Gutowski, W J [Department of Geological and Atmospheric Sciences, Iowa State University, Iowa (United States); Adedoyin, A, E-mail: babiodun@csag.uct.ac.z [Department of Physics, University of Botswana, Gaborone (Botswana)

    2010-08-15

    The study found that deforestation causes more monsoon moisture to be retained in the mid-troposphere, thereby reducing the northward transport of moisture needed for rainfall over West Africa. Hence, deforestation has dynamical impacts on the West African monsoon and rainfall.

  17. Batrachochytrium dendrobatidis in amphibians of Cameroon, including first records for caecilians.

    Science.gov (United States)

    Doherty-Bone, T M; Gonwouo, N L; Hirschfeld, M; Ohst, T; Weldon, C; Perkins, M; Kouete, M T; Browne, R K; Loader, S P; Gower, D J; Wilkinson, M W; Rödel, M O; Penner, J; Barej, M F; Schmitz, A; Plötner, J; Cunningham, A A

    2013-02-28

    Amphibian chytrid fungus Batrachochytrium dendrobatidis (Bd) has been hypothesised to be an indigenous parasite of African amphibians. In Cameroon, however, previous surveys in one region (in the northwest) failed to detect this pathogen, despite the earliest African Bd having been recorded from a frog in eastern Cameroon, plus one recent record in the far southeast. To reconcile these contrasting results, we present survey data from 12 localities across 6 regions of Cameroon from anurans (n = 1052) and caecilians (n = 85) of ca. 108 species. Bd was detected in 124 amphibian hosts at 7 localities, including Mt. Oku, Mt. Cameroon, Mt. Manengouba and lowland localities in the centre and west of the country. None of the hosts were observed dead or dying. Infected amphibian hosts were not detected in other localities in the south and eastern rainforest belt. Infection occurred in both anurans and caecilians, making this the first reported case of infection in the latter order (Gymnophiona) of amphibians. There was no significant difference between prevalence and infection intensity in frogs and caecilians. We highlight the importance of taking into account the inhibition of diagnostic qPCR in studies on Bd, based on all Bd-positive hosts being undetected when screened without bovine serum albumin in the qPCR mix. The status of Bd as an indigenous, cosmopolitan amphibian parasite in Africa, including Cameroon, is supported by this work. Isolating and sequencing strains of Bd from Cameroon should now be a priority. Longitudinal host population monitoring will be required to determine the effects, if any, of the infection on amphibians in Cameroon.

  18. How can small hydro energy and other renewable energy mitigate impact of climate change in remote Central Africa: Cameroon case study.

    Science.gov (United States)

    Kenfack, Joseph; Bignom, Blaise

    2015-04-01

    Central Africa owns important renewable energy potential, namely hydro, solar and biomass. This important potential is still suffering from poor development up to the point where the sub region is still abundantly using the fossil energy and biomass as main power source. This is harmful to the climate and the situation is still ongoing. The main cause of the poor use of renewable energy is the poor management of resources by governments who have not taken the necessary measures to boost the renewable energy sector. Since the region is experiencing power shortage, thermal plants are among other solutions planned or under construction. Firewood is heavily used in remote areas without a sustainability program behind. This solution is not environment friendly and hence is not a long term solution. Given the fact that the region has the highest hydro potential of the continent, up to one-quarter of the world's tropical forest, important oil production with poor purchase power, the aim of this paper is to identify actions for improved access to sustainable, friendly, affordable energy services to users as well as a significant improvement of energy infrastructure in Central Africa and the promotion of small hydro and other renewable energy. The work will show at first the potential for the three primary energy sources which are solar, biomass and hydro while showing where available the level of development, with an emphasis on small hydro. Then identified obstacles for the promotion of clean energy will be targeted. From lessons learned, suggestions will be made to help the countries develop an approach aiming at developing good clean energy policy to increase the status of renewable energy and better contribute to fight against climate change. Cameroon has a great renewable energy potential and some data are available on energy. From the overview of institutional structure reform of the Cameroon power sector and assessments, specific suggestions based on the weaknesses

  19. Evaluation of rainfall simulations over West Africa in dynamically downscaled CMIP5 global circulation models

    Science.gov (United States)

    Akinsanola, A. A.; Ajayi, V. O.; Adejare, A. T.; Adeyeri, O. E.; Gbode, I. E.; Ogunjobi, K. O.; Nikulin, G.; Abolude, A. T.

    2017-03-01

    This study presents evaluation of the ability of Rossby Centre Regional Climate Model (RCA4) driven by nine global circulation models (GCMs), to skilfully reproduce the key features of rainfall climatology over West Africa for the period of 1980-2005. The seasonal climatology and annual cycle of the RCA4 simulations were assessed over three homogenous subregions of West Africa (Guinea coast, Savannah, and Sahel) and evaluated using observed precipitation data from the Global Precipitation Climatology Project (GPCP). Furthermore, the model output was evaluated using a wide range of statistical measures. The interseasonal and interannual variability of the RCA4 were further assessed over the subregions and the whole of the West Africa domain. Results indicate that the RCA4 captures the spatial and interseasonal rainfall pattern adequately but exhibits a weak performance over the Guinea coast. Findings from the interannual rainfall variability indicate that the model performance is better over the larger West Africa domain than the subregions. The largest difference across the RCA4 simulated annual rainfall was found in the Sahel. Result from the Mann-Kendall test showed no significant trend for the 1980-2005 period in annual rainfall either in GPCP observation data or in the model simulations over West Africa. In many aspects, the RCA4 simulation driven by the HadGEM2-ES perform best over the region. The use of the multimodel ensemble mean has resulted to the improved representation of rainfall characteristics over the study domain.

  20. Molecular Epidemiology of HIV Type 1 CRF02_AG in Cameroon and African Patients Living in Italy

    Science.gov (United States)

    Véras, Nazle Mendonca Collaço; Santoro, Maria Mercedes; Gray, Rebecca R.; Tatem, Andrew J.; Presti, Alessandra Lo; Olearo, Flaminia; Cappelli, Giulia; Colizzi, Vittorio; Takou, Desiré; Torimiro, Judith; Russo, Gianluca; Callegaro, Annapaola; Salpini, Romina; D'Arrigo, Roberta; Perno, Carlo-Federico; Goodenow, Maureen M.; Ciccozzi, Massimo

    2011-01-01

    Abstract HIV-1 CRF02_AG accounts for >50% of infected individuals in Cameroon. CRF02_AG prevalence has been increasing both in Africa and Europe, particularly in Italy because of migrations from the sub-Saharan region. This study investigated the molecular epidemiology of CRF02_AG in Cameroon by employing Bayesian phylodynamics and analyzed the relationship between HIV-1 CRF02_AG isolates circulating in Italy and those prevalent in Africa to understand the link between the two epidemics. Among 291 Cameroonian reverse transcriptase sequences analyzed, about 70% clustered within three distinct clades, two of which shared a most recent common ancestor, all related to sequences from Western Africa. The major Cameroonian clades emerged during the mid-1970s and slowly spread during the next 30 years. Little or no geographic structure was detected within these clades. One of the major driving forces of the epidemic was likely the high accessibility between locations in Southern Cameroon contributing to the mobility of the population. The remaining Cameroonian sequences and the new strains isolated from Italian patients were interspersed mainly within West and Central African sequences in the tree, indicating a continuous exchange of CRF02_AG viral strains between Cameroon and other African countries, as well as multiple independent introductions in the Italian population. The evaluation of the spread of CRF02_AG may provide significant insight about the future dynamics of the Italian and European epidemic. PMID:21453131

  1. Observations of OH and HO2 radicals over West Africa

    Directory of Open Access Journals (Sweden)

    D. E. Heard

    2010-03-01

    Full Text Available The hydroxyl radical (OH plays a key role in the oxidation of trace gases in the troposphere. However, observations of OH and the closely related hydroperoxy radical (HO2 have been sparse, especially in the tropics. Based on a low-pressure laser-induced fluorescence technique (FAGE – Fluorescence Assay by Gas Expansion, an instrument has been developed to measure OH and HO2 aboard the Facility for Airborne Atmospheric Measurement (FAAM BAe-146 research aircraft. The instrument is described and the calibration method is discussed. During the African Monsoon Multidisciplinary Analyses (AMMA campaign, observations of OH and HO2 (HOx were made in the boundary layer and free troposphere over West Africa on 13 flights during July and August 2006. Mixing ratios of both OH and HO2 were found to be highly variable but followed a diurnal cycle, with a median HO2/OH ratio of 95. Daytime OH observations were compared with the primary production rate of OH from ozone photolysis in the presence of water vapour. Daytime HO2 observations were generally reproduced by a simple steady-state HOx calculation, where HOx was assumed to be formed from the primary production of OH and lost through HO2 self-reaction. Deviations between the observations and this simple model were found to be grouped into a number of specific cases: (a in the presence of high levels of isoprene in the boundary layer, (b within a biomass burning plume and (c within cloud. In the forested boundary layer, HO2 was underestimated at altitudes below 500 m but overestimated between 500 m and 2 km. In the biomass burning plume, OH and HO2 were both significantly reduced compared to calculations. HO2 was sampled in and around cloud, with significant short-lived reductions of HO2 observed. HO2 observations were better reproduced by a steady state calculation with heterogeneous loss of HO2 onto cloud droplets included. Up to 9 pptv of HO2 was observed at night, increasing early in the morning

  2. A Multivariate Analysis of Freshwater Variability over West Africa

    Science.gov (United States)

    Andam-Akorful, S. A.; He, X.; Ferreira, V. G.; Quaye-Ballard, J. A.

    2015-12-01

    As one of the most vulnerable regions to climate change, West Africa (WA) has since the 1970s suffered sustained reduction in rainfall amounts, leading to droughts and associated negative impacts on its water resources. Although rainfall rates have been reported to have experienced a degree of recovery, dry conditions persist. Additionally, the region faces perennial flooding, thus resulting in a highly variable hydrologic regime due to the extreme climate conditions. This therefore necessitates routine monitoring of the WA's freshwater reserves and its response to climate variations at the short and long term scales to aid sustainable use and management. However, this monitoring is hampered by data deficiency issues within the region. Consequently, dynamics leading to changes in water availability over the region are not completely understood. In this work, the recent flux and state of freshwater availability over WA from 1979 to 2013 is assessed by investigating the coupled variability of GRACE-derived terrestrial water storage (TWS) and its changes (TWSC) estimates with rainfall, evapotranspiration, and land surface air temperature (LSAT), as well as, major global and regional teleconnection indices using complex principal component analysis and wavelet transforms. Since GRACE covers a relatively short period, and thereby present challenges for long to medium term analyses, Artificial Neural Network (ANN) is employed to extend the GRACE series to 1979. The results from the ANN proved to be robust upon evaluation; spatially-averaged series for major basins and sub-climatic zones, as well as, the whole of WA presented RMSE, Nash-Sutcliffe efficient, and coefficient of determination (R2) of 11.83 mm, 0.76 and 0.89 respectively. Overall, the results obtained from this study indicate that, sustained increase in water flux, in terms of TWSC, contributed to a resurgence in freshwater reserves in the 21st century over WA from the low levels in the late 20th century

  3. Risk maps of Lassa fever in West Africa.

    Directory of Open Access Journals (Sweden)

    Elisabeth Fichet-Calvet

    Full Text Available BACKGROUND: Lassa fever is caused by a viral haemorrhagic arenavirus that affects two to three million people in West Africa, causing a mortality of between 5,000 and 10,000 each year. The natural reservoir of Lassa virus is the multi-mammate rat Mastomys natalensis, which lives in houses and surrounding fields. With the aim of gaining more information to control this disease, we here carry out a spatial analysis of Lassa fever data from human cases and infected rodent hosts covering the period 1965-2007. Information on contemporary environmental conditions (temperature, rainfall, vegetation was derived from NASA Terra MODIS satellite sensor data and other sources and for elevation from the GTOPO30 surface for the region from Senegal to the Congo. All multi-temporal data were analysed using temporal Fourier techniques to generate images of means, amplitudes and phases which were used as the predictor variables in the models. In addition, meteorological rainfall data collected between 1951 and 1989 were used to generate a synoptic rainfall surface for the same region. METHODOLOGY/PRINCIPAL FINDINGS: Three different analyses (models are presented, one superimposing Lassa fever outbreaks on the mean rainfall surface (Model 1 and the other two using non-linear discriminant analytical techniques. Model 2 selected variables in a step-wise inclusive fashion, and Model 3 used an information-theoretic approach in which many different random combinations of 10 variables were fitted to the Lassa fever data. Three combinations of absenceratiopresence clusters were used in each of Models 2 and 3, the 2 absenceratio1 presence cluster combination giving what appeared to be the best result. Model 1 showed that the recorded outbreaks of Lassa fever in human populations occurred in zones receiving between 1,500 and 3,000 mm rainfall annually. Rainfall, and to a much lesser extent temperature variables, were most strongly selected in both Models 2 and 3, and

  4. Issues of Sustainability of Coastal Groundwater Resources: Benin, West Africa

    Directory of Open Access Journals (Sweden)

    Andrew D. Mullen

    2010-08-01

    Full Text Available The largest city in Benin, West Africa (Cotonou, is reliant upon groundwater for its public water supply. This groundwater is derived from the Godomey well field which is located approximately 5 Km north of the coast of the Atlantic Ocean and in close proximity to Lake Nokoue—a shallow lake containing water with elevated concentration of chloride and other elements. Historical data indicate increased chloride concentration in a number of wells nearest to the lake, with unknown contribution from groundwater encroachment from the coastal area. Hence, there is substantial interest in better characterizing this groundwater system for the purpose of determining appropriate management practices and degree of sustainability. Among the efforts attempted to date are a series of numerical models ranging from assessment of flow to a recent effort to include density-dependent transport from the lake. In addition, substantial field characterization has been pursued including assessment of shallow water chemistry along the region of the coastal lagoon and border of the lake, characterization of hydraulic response to pumpage in the aquifer system, estimation of the distribution of electrical resistivity with depth along the coastal lagoons, and installation of multi-level piezometers at seven locations in the lake. When integrated across methods, these numerical and field results indicate that the lake remains a primary concern in terms of a source of salinity in the aquifer. Further, the coastal region appears to be more complex than previously suggested and may represent a future source of salt-water encroachment as suggested by current presence of saline waters at relatively shallow depths along the coast. Finally, hydraulic testing suggests that both natural and pumping-based fluctuations in water levels are present in this system. Substantial additional characterization and modeling efforts may provide a significantly greater understanding of the

  5. Intestinal parasitic infections in HIV infected and non-infected patients in a low HIV prevalence region, West-Cameroon.

    Science.gov (United States)

    Nkenfou, Céline Nguefeu; Nana, Christelle Tafou; Payne, Vincent Khan

    2013-01-01

    The magnitude of intestinal parasitic infection in acquired immunodeficiency syndrome patients requires careful consideration in the developing world where poor nutrition is associated with poor hygiene and several tropical diseases. However, there have been very few studies addressing this issue in Cameroon. This study was conducted to determine the prevalence of intestinal parasitosis in HIV/AIDS patients in Dschang -Cameroon. Stool and blood specimens from HIV/AIDS patients and control group were screened respectively for intestinal parasites and for HIV antibodies. Intestinal parasites were identified using direct microscopy, formalin-ether concentration and Ziehl Neelsen methods. Out of 396 participants recruited among patients consulting at hospital, 42 (10.6%) were HIV positive, thirty of them treatment naïve. The overall prevalence of intestinal parasites was 14.64%. Out of 42 HIV/AIDS patients, 59.5% (25/42) were infected with intestinal parasites, while only 9.32% (33/354) of the HIV negative patients were infected with intestinal parasites. The parasites detected in our study population included Crystosporidium parvum (2.53%), Entamoeba histolytica (7.52%), Entamoeba coli (4.04%), Giardia lamblia (0.25%), Trichuris trichura (0.25%), Strongyloides stercoralis (0.25%) and Taenia spp. (0.25%). In the HIV infected group, Crystosporidium parvum (19.04%), Entamoeba histolytica (19.04%), Entamoeba coli (21.42%), Giardia lamblia (2.38%), Strongyloides stercoralis (0.25%) and Taenia spp. (0.25%) were found. Crystosporidium parvum was found to be significantly higher in HIV/AIDS patients than in controls (Pintestinal parasitosis. Routine examinations of stool samples for parasites would significantly benefit the HIV patients by contributing in reducing morbidity and improving the efficiency of antiretroviral treatment. Even after the introduction of free anti-retroviral drugs, opportunistic intestinal infections are still a threat. HIV patients should be screened

  6. Aid and Authoritarianism in Africa

    DEFF Research Database (Denmark)

    In 2013 almost half of Africa’s top aid recipients were ruled by authoritarian regimes. While the West may claim to promote democracy and human rights, in practice major bilateral and international donors, such as USAID , DFID , the World Bank and the European Commission, have seen their aid...... and Authoritarianism in Africa sheds light on the political intricacies and moral dilemmas raised by the relationship between foreign aid and autocratic rule in Africa. Through contributions by leading experts exploring the revival of authoritarian development politics in Ethiopia, Uganda, Rwanda, Cameroon, Mozambique...

  7. Modeling the impact of changes in Atlantic sea surface temperature on the climate of West Africa

    Science.gov (United States)

    Adeniyi, Mojisola O.

    2016-08-01

    This study assesses the impacts of warming/cooling of the Atlantic sea surface temperature (SST) on the climate of West Africa using Version 4.4 of Regional Climate Model (RegCM4.4) of International Center for Theoretical Physics, Trieste, Italy. The 1-2 K cooling and warming of the Atlantic SST both result in tripole temperature and precipitation change structure, having a northwest-southeast orientation over West Africa. Findings reveal that the responses of precipitation and temperature to the Atlantic SST cooling are opposite to those for the Atlantic SST warming and these responses intensify with increased warming/cooling of the Atlantic SST. The structure of the change in climate is attributed to the response of atmospheric/soil moisture gradient and orientation of orography in West Africa.

  8. What factors might have led to the emergence of Ebola in West Africa?

    Science.gov (United States)

    Alexander, Kathleen A; Sanderson, Claire E; Marathe, Madav; Lewis, Bryan L; Rivers, Caitlin M; Shaman, Jeffrey; Drake, John M; Lofgren, Eric; Dato, Virginia M; Eisenberg, Marisa C; Eubank, Stephen

    2015-01-01

    An Ebola outbreak of unprecedented scope emerged in West Africa in December 2013 and presently continues unabated in the countries of Guinea, Sierra Leone, and Liberia. Ebola is not new to Africa, and outbreaks have been confirmed as far back as 1976. The current West African Ebola outbreak is the largest ever recorded and differs dramatically from prior outbreaks in its duration, number of people affected, and geographic extent. The emergence of this deadly disease in West Africa invites many questions, foremost among these: why now, and why in West Africa? Here, we review the sociological, ecological, and environmental drivers that might have influenced the emergence of Ebola in this region of Africa and its spread throughout the region. Containment of the West African Ebola outbreak is the most pressing, immediate need. A comprehensive assessment of the drivers of Ebola emergence and sustained human-to-human transmission is also needed in order to prepare other countries for importation or emergence of this disease. Such assessment includes identification of country-level protocols and interagency policies for outbreak detection and rapid response, increased understanding of cultural and traditional risk factors within and between nations, delivery of culturally embedded public health education, and regional coordination and collaboration, particularly with governments and health ministries throughout Africa. Public health education is also urgently needed in countries outside of Africa in order to ensure that risk is properly understood and public concerns do not escalate unnecessarily. To prevent future outbreaks, coordinated, multiscale, early warning systems should be developed that make full use of these integrated assessments, partner with local communities in high-risk areas, and provide clearly defined response recommendations specific to the needs of each community.

  9. The Effect of Long Lasting Insecticide Bed Net Use on Malaria Prevalence in the Tombel Health District, South West Region-Cameroon

    Directory of Open Access Journals (Sweden)

    Eric B. Fokam

    2016-01-01

    Full Text Available Malaria remains a major public health problem in Africa, and its prevalence in Cameroon stands at 29%. Long Lasting Insecticide Nets (LLINs were distributed in 2011 to reduce malaria mortality and morbidity; however, assessment of this intervention is scanty. The present study in the Tombel health district (THD investigated the impact of this distribution on malaria prevalence. A total of 31,657 hospital records from 3 health facilities in 3 health areas for 2010–2013 were examined. Records for 2010 and 2011 provided predistribution baseline data, while those of 2012 and 2013 represented postdistribution data. 8,679 (27.4% patients were positive for malaria. Children below 5 years had the highest prevalence (40.7%. The number of confirmed cases was highest from June to August (peak rainy season. Malaria prevalence was higher in males (25.3% than in females (23.2%. Malaria prevalence increased in THD from 26.7% in 2010 to 30.7% in 2011 but dropped to 22.7% in 2012 and then increased in 2013 to 29.5%. There was an overall drop in the total number of confirmed malaria cases in 2012; this decrease was significant in Ebonji (p<0.001 and Nyasoso (p<0.015 health areas. The distribution of LLINs led to a short lived reduction in malaria prevalence in THD. LLIN distribution and other control activities should be reinforced to keep malaria prevalence low especially among the 0–5-year group.

  10. Robust features of future climate change impacts on sorghum yields in West Africa

    OpenAIRE

    Sultan, Benjamin; Guan, K; Kouressy, M.; Biasutti, M.; Piani, C.; Hammer, G.L.; McLean, G.; Lobell, D.B.

    2014-01-01

    International audience; West Africa is highly vulnerable to climate hazards and better quantification and understanding of the impact of climate change on crop yields are urgently needed. Here we provide an assessment of near-term climate change impacts on sorghum yields in West Africa and account for uncertainties both in future climate scenarios and in crop models. Towards this goal, we use simulations of nine bias-corrected CMIP5 climate models and two crop models (SARRA-H and APSIM) to ev...

  11. Impact of the Indian part of the summer MJO on West Africa using nudged climate simulations

    Energy Technology Data Exchange (ETDEWEB)

    Mohino, Elsa [Universite Pierre et Marie Curie, LOCEAN/IPSL, Paris Cedex 05 (France); Universidad de Sevilla, Sevilla (Spain); Janicot, Serge [Universite Pierre et Marie Curie, LOCEAN/IPSL, IRD, Paris Cedex 05 (France); Douville, Herve [Meteo-France/CNRM-GAME, Toulouse (France); Li, Laurent Z.X. [Universite Pierre et Marie Curie, LMD/IPSL, CNRS, Paris (France)

    2012-06-15

    Observational evidence suggests a link between the summer Madden Julian Oscillation (MJO) and anomalous convection over West Africa. This link is further studied with the help of the LMDZ atmospheric general circulation model. The approach is based on nudging the model towards the reanalysis in the Asian monsoon region. The simulation successfully captures the convection associated with the summer MJO in the nudging region. Outside this region the model is free to evolve. Over West Africa it simulates convection anomalies that are similar in magnitude, structure, and timing to the observed ones. In accordance with the observations, the simulation shows that 15-20 days after the maximum increase (decrease) of convection in the Indian Ocean there is a significant reduction (increase) in West African convection. The simulation strongly suggests that in addition to the eastward-moving MJO signal, the westward propagation of a convectively coupled equatorial Rossby wave is needed to explain the overall impact of the MJO on convection over West Africa. These results highlight the use of MJO events to potentially predict regional-scale anomalous convection and rainfall spells over West Africa with a time lag of approximately 15-20 days. (orig.)

  12. Genetic diversity, evolutionary history and implications for conservation of the lion (Panthera leo) in West and Central Africa

    NARCIS (Netherlands)

    Bertola, L. D.; Van Hooft, W. F.; Vrieling, K.; Uit de Weerd, D. R.; York, D. S.; Bauer, H.; Prins, H. H. T.; Funston, P. J.; Udo de Haes, H. A.; Leirs, H.; Van Haeringen, W. A.; Sogbohossou, E.; Tumenta, P. N.; De Iongh, H. H.

    2012-01-01

    Aim: In recent decades there has been a marked decline in the numbers of African lions (Panthera leo), especially in West Africa where the species is regionally endangered. Based on the climatological history of western Africa, we hypothesize that West and Central African lions have a unique evoluti

  13. The Challenge of Drug Trafficking to Democratic Governance and Human Security in West Africa

    Science.gov (United States)

    2013-05-01

    transformation. In the same spirit of bold curiosity that compelled the men and women who, like Letort, settled the American west, the Strategic...and methamphetamines, ecstasy, and ketamine from West Africa toward Asia (and Australia); these often tran- sit via Malaysia or Indonesia, to Japan...traders and business people: A successful individual entrepreneur invites one or more junior relatives or dependents to join him or her in a business

  14. Intestinal parasitic infections in HIV infected and non-infected patients in a low HIV prevalence region, West-Cameroon.

    Directory of Open Access Journals (Sweden)

    Céline Nguefeu Nkenfou

    Full Text Available The magnitude of intestinal parasitic infection in acquired immunodeficiency syndrome patients requires careful consideration in the developing world where poor nutrition is associated with poor hygiene and several tropical diseases. However, there have been very few studies addressing this issue in Cameroon. This study was conducted to determine the prevalence of intestinal parasitosis in HIV/AIDS patients in Dschang -Cameroon. Stool and blood specimens from HIV/AIDS patients and control group were screened respectively for intestinal parasites and for HIV antibodies. Intestinal parasites were identified using direct microscopy, formalin-ether concentration and Ziehl Neelsen methods. Out of 396 participants recruited among patients consulting at hospital, 42 (10.6% were HIV positive, thirty of them treatment naïve. The overall prevalence of intestinal parasites was 14.64%. Out of 42 HIV/AIDS patients, 59.5% (25/42 were infected with intestinal parasites, while only 9.32% (33/354 of the HIV negative patients were infected with intestinal parasites. The parasites detected in our study population included Crystosporidium parvum (2.53%, Entamoeba histolytica (7.52%, Entamoeba coli (4.04%, Giardia lamblia (0.25%, Trichuris trichura (0.25%, Strongyloides stercoralis (0.25% and Taenia spp. (0.25%. In the HIV infected group, Crystosporidium parvum (19.04%, Entamoeba histolytica (19.04%, Entamoeba coli (21.42%, Giardia lamblia (2.38%, Strongyloides stercoralis (0.25% and Taenia spp. (0.25% were found. Crystosporidium parvum was found to be significantly higher in HIV/AIDS patients than in controls (P<0.05. Multivariate analysis showed that the HIV status and the quality of water were the major risk factors for intestinal parasitosis. Routine examinations of stool samples for parasites would significantly benefit the HIV patients by contributing in reducing morbidity and improving the efficiency of antiretroviral treatment. Even after the introduction

  15. A preliminary analysis of some epidemiological factors involved in porcine cysticercosis in Bafut and Santa subdivisions, North West Region of Cameroon

    Institute of Scientific and Technical Information of China (English)

    Nchang Allo Nicoline Ngwing; J Wabo Pon; Mpoame Mbida; A Zoli Pagnah; H Njakoi; CF Bilong Bilong

    2012-01-01

    Objective:To examine the magnitude and some risk factors of porcine cysticercosis in Bafut and Santa, two sub-divisions noted for pig farming in the North West Region of Cameroon. Methods:A total of 499 pigs in 300 households were examined by tongue inspection and serologically by Ag-ELISA. Information was sought on the age and sex of the animals, prevailing husbandry systems, types of feed, the state of each pen and the state of toilets. Futhermore, a questionnaire was administered to the farmers to determine their awareness on taeniasis/cysticercosis and related factors. Results:The prevalence of the disease was significantly higher in Santa (10.2%) than in Bafut (4.2%), although there was a higher level of awareness in both localities (62.3%). Age of pigs, traditional rearing systems (roaming, tethered, earth floor pen, raised floor pen), faecal disposal in the environment and poor sanitation significantly influenced the seroprevalence of porcine cysticercosis in both localities. Most farmers (79.7%) used a combination of concentrate, grass and kitchen waste to feed pigs. Financial loss from porcine cysticercosis was estimated at 346 900 CFA representing 2% of total income. Conclusions: Control measures advanced here include sensitization campaigns, periodic examination and treatment of infected pigs by veterinarians, improved husbandry systems, proper use of standard latrines regularly inspected by sanitary officers, and sound hygienic and sanitary practices.

  16. Short communication: analysis of the integrase gene from HIV type 1-positive patients living in a rural area of West Cameroon.

    Science.gov (United States)

    Turriziani, Ombretta; Montagna, Claudia; Falasca, Francesca; Bucci, Mauro; Russo, Gianluca; Lichtner, Miriam; Sobze, Martin Sanou; Vullo, Vincenzo; Pistello, Mauro; Antonelli, Guido

    2012-12-01

    Major mutations associated with HIV-I integrase inhibitors (INI) resistance are rare in INI-naive patients. However, polymorphisms at positions that may influence the genetic barrier and/or drive the selection of specific INI resistance pathways are common in HIV non-B subtypes. The aim was to evaluate the presence of natural polymorphisms and/or INI resistance mutations in HIV-1 non-B subtype samples obtained from INI-naive patients living in rural west Cameroon. Thirty-three HIV-1 non-B samples were obtained from INI-naive African women and, as controls, 15 samples of HIV-1 subtype B were obtained from antiretroviral-naive Italian patients. The integrase gene was amplified and sequenced using Trugene Core Reagents. Several amino acid positions in B and non-B subtypes were found to be polymorphic. Interestingly, two patients infected with the CRF02_AG subtype had the resistance mutations N155H and E157Q/E and 12% of African samples had an amino acid substitution at position 143. Silent mutations leading to a higher increment of genetic barriers were detected at 140 and 151 positions in non B-subtypes. Although most polymorphisms may have little effect on INI susceptibility, the IN gene variations found in the present study should be taken into consideration as they may facilitate or delay the emergence of variants fully resistant to INIs.

  17. Seroprevalence and risk factors of human cysticercosis and taeniasis prevalence in a highly endemic area of epilepsy in Bangoua, west Cameroon.

    Science.gov (United States)

    Nkouawa, Agathe; Dschanou, Armel Romeo; Moyou-Somo, Roger; Sako, Yasuhito; Ito, Akira

    2017-01-01

    Cysticercosis caused by the larvae of Taenia solium is a serious and emerging threat to public health in the endemic areas as well as in the non-endemic areas. Neurocysticercosis, an affection of the central nervous system is a leading cause of epilepsy in endemic areas. This study was carried out to investigate human cysticercosis, taeniasis and risk factors, and also their association with epilepsy in Bangoua, west Cameroon where epilepsy is highly prevalent. Out of 384 people investigated, 12 (3.1%) exhibited antibody response against low molecular weight antigens of T. solium by ELISA. Immunoblot revealed that six persons (1.6%) were seropositive with the same antigens. Among 61 epileptic patients, only one was seropositive by immunoblot and the study did not find any statistically significant difference (P>0.05) in seropositivity to T. solium between epileptic persons (1/61, 1.6%) and non-epileptic group (5/323, 1.5%). In addition, cysticercosis was associated with households eating pork meat from pigs slaughtered at home, but not with other factors. The risk factors including pig farming, the consumption of pork meat, vegetables, and non-drinkable water were attenuated by the relatively good hygiene and pig husbandry practices of the population. No egg of Taenia was found in stool by microscopic examination. All data obtained in this study suggested that cysticercosis might not be the principal causative agent of epilepsy in this area.

  18. Magnetic fabrics of the Miocene ignimbrites from West-Cameroon: Implications for pyroclastic flow source and sedimentation

    Science.gov (United States)

    Gountié Dedzo, M.; Nédélec, A.; Nono, A.; Njanko, T.; Font, E.; Kamgang, P.; Njonfang, E.; Launeau, P.

    2011-06-01

    The Miocene ignimbrites of Mounts Bambouto and Bamenda located in the central part of Cameroon Volcanic Line are generally made of welded and non-welded massive lapilli tuff and lithic breccias. These discontinuous deposits cover a total area of 180 km 2 with thickness ranging from 25 to 200 m. The different facies contain several lithic fragments of mainly trachytic nature. The devitrified matrix of the welded ignimbrites is constituted by sanidine, anorthoclase, quartz, plagioclase, clinopyroxene, biotite, Fe-Ti oxides and devitrified fiammes. Anisotropy of magnetic susceptibility (AMS) is used to characterize magnetic fabrics and to provide an estimate of flow direction of each ignimbrite sheet. Magnetic mineralogy results from different flow units show that titanomagnetite, titanohematite, maghemite and goethite with grain size ranging from coarse MD to very fine SP are the main magnetic carriers of these ignimbrites. Inferred transport directions based on the AMS data and field indicators show that Bambouto caldera is the source of main pyroclastic deposits of Mount Bambouto. In southwestern Mount Bamenda, Santa-Mbu caldera or Bambouto caldera constituted the probable emission center of Mbengwi, Bamenda and Mbu ignimbrite sheets, whereas magnetic fabrics of Bambili, Sabga and Big Babanki ignimbrites demonstrate that these deposits were emitted from a northeastern source, namely Oku vent in Mount Oku. A small number of subvertical AMS fabrics correspond to rocks possibly modified by an elutriation process.

  19. Infection Prevention and Control for Ebola in Health Care Settings - West Africa and United States.

    Science.gov (United States)

    Hageman, Jeffrey C; Hazim, Carmen; Wilson, Katie; Malpiedi, Paul; Gupta, Neil; Bennett, Sarah; Kolwaite, Amy; Tumpey, Abbigail; Brinsley-Rainisch, Kristin; Christensen, Bryan; Gould, Carolyn; Fisher, Angela; Jhung, Michael; Hamilton, Douglas; Moran, Kerri; Delaney, Lisa; Dowell, Chad; Bell, Michael; Srinivasan, Arjun; Schaefer, Melissa; Fagan, Ryan; Adrien, Nedghie; Chea, Nora; Park, Benjamin J

    2016-07-08

    The 2014-2016 Ebola virus disease (Ebola) epidemic in West Africa underscores the need for health care infection prevention and control (IPC) practices to be implemented properly and consistently to interrupt transmission of pathogens in health care settings to patients and health care workers. Training and assessing IPC practices in general health care facilities not designated as Ebola treatment units or centers became a priority for CDC as the number of Ebola virus transmissions among health care workers in West Africa began to affect the West African health care system and increasingly more persons became infected. CDC and partners developed policies, procedures, and training materials tailored to the affected countries. Safety training courses were also provided to U.S. health care workers intending to work with Ebola patients in West Africa. As the Ebola epidemic continued in West Africa, the possibility that patients with Ebola could be identified and treated in the United States became more realistic. In response, CDC, other federal components (e.g., Office of the Assistant Secretary for Preparedness and Response) and public health partners focused on health care worker training and preparedness for U.S. health care facilities. CDC used the input from these partners to develop guidelines on IPC for hospitalized patients with known or suspected Ebola, which was updated based on feedback from partners who provided care for Ebola patients in the United States. Strengthening and sustaining IPC helps health care systems be better prepared to prevent and respond to current and future infectious disease threats.The activities summarized in this report would not have been possible without collaboration with many U.S. and international partners (http://www.cdc.gov/vhf/ebola/outbreaks/2014-west-africa/partners.html).

  20. Unravelling institutional determinants affecting change in agriculture in West Africa

    NARCIS (Netherlands)

    Struik, P.C.; Klerkx, L.W.A.; Hounkonnou, D.

    2014-01-01

    This paper compares lessons learned from nine studies that explored institutional determinants of innovation towards sustainable intensification of West African agriculture. The studies investigated issues relating to crop, animal, and resources management in Benin, Ghana, and Mali. The constraints

  1. Study Abroad in West Africa: An Interdisciplinary Program of International Education

    Science.gov (United States)

    Lowe, Tony B.; Dozier, Cheryl D.; Hunt-Hurst, Patricia; Smith, Bettye P.

    2008-01-01

    This article describes development of an interdisciplinary study abroad program to West Africa at the University of Georgia to help students gain a global perspective. The program is interdisciplinary with several disciplines including social work, clothing and textile, history, and teacher education. This article discusses/highlights a need for a…

  2. Potential impact of climate and socioeconomic changes on future agricultural land use in West Africa

    Directory of Open Access Journals (Sweden)

    K. F. Ahmed

    2015-07-01

    agricultural land use is primarily climate-driven in the western part of West Africa and socioeconomically driven in the eastern part. Analysis of results from multiple decision-making scenarios suggests that human adaptation characterized by science-informed decision making to minimize land use could be very effective in many parts of the region.

  3. Soil salinity and acidity: Spatial variability and effects on rice production in West Africa's mangrove zone.

    NARCIS (Netherlands)

    Sylla, M.

    1994-01-01

    In the mangrove environment of West Africa, high spatial and temporal variability of soil constraints (salinity and acidity) to rice production is a problem for the transfer and adoption of new agronomic techniques, for land use planning, and for soil and water management. Recently, several National

  4. Imaging suggestive of Pentososmiasis of lung in the forest region of Guinea in West Africa

    Institute of Scientific and Technical Information of China (English)

    Bafende Aombe Eric.; Guilavogui Agathe.; Kolié Cece

    2012-01-01

    The authors are reporting the first case of Human pentastomiasis in the forest region of Guinea in West Africa. The 52 years old man Guinean farmer has a history of eating snakes.The authors recommend to cook well snake before consumption and a moderation on the snake consumption.

  5. Characteristics of Zircon in Placer Deposits along the West Coast of South Africa

    NARCIS (Netherlands)

    Philander, C.; Rozendaal, A.; de Meijer, R.J.

    1999-01-01

    Mining along the west coast of South Africa is dominated by the exploitation of onshore and offshore diamond deposits. The relatively recent discovery of vast resources of heavy minerals in the area has resulted in the establishment of a major related industry. Today, Namakwa Sands is a 10-million-t

  6. World market or regional integration and food security in West Africa

    NARCIS (Netherlands)

    L.J. de Haan (Leo); A. Klaasse Bos (Andries); C. Lutz (Clemens)

    1994-01-01

    textabstractThe problem of food security in West Africa was put on the international agenda in 1974 at the international food conference in Rome following the Great Sahelian Drought of 1968-1973. In those years preoccupation with food security was limited mainly to the Sahel countries and concentrat

  7. Organised labour and neo-liberal economic and political reforms in West and Central Africa

    NARCIS (Netherlands)

    Konings, P.J.J.

    2003-01-01

    This article examines the impact of current neoliberal political reforms on trade union performance in West and Central Africa. To what extent have trade unions been involved in the political restructuring of the State? Has political liberalization constrained or enhanced their political influence a

  8. Cultural Issues in Secondary Education Development in West Africa: Away from Colonial Survivals, towards Neocolonial Influences.

    Science.gov (United States)

    Quist, Hubert O.

    2001-01-01

    In urban Ghana and Cote d'Ivoire (Ivory Coast), cultural factors arising from West Africa's "triple cultural heritage" (African, Euro-Christian, and Islamic) and globalization place considerable strains on secondary education and have implications for postcolonial nation-building and development. Surveys of 200 secondary students in the…

  9. Stochastic rainfall modeling in West Africa: Parsimonious approaches for domestic rainwater harvesting assessment

    Science.gov (United States)

    Cowden, Joshua R.; Watkins, David W., Jr.; Mihelcic, James R.

    2008-10-01

    SummarySeveral parsimonious stochastic rainfall models are developed and compared for application to domestic rainwater harvesting (DRWH) assessment in West Africa. Worldwide, improved water access rates are lowest for Sub-Saharan Africa, including the West African region, and these low rates have important implications on the health and economy of the region. Domestic rainwater harvesting (DRWH) is proposed as a potential mechanism for water supply enhancement, especially for the poor urban households in the region, which is essential for development planning and poverty alleviation initiatives. The stochastic rainfall models examined are Markov models and LARS-WG, selected due to availability and ease of use for water planners in the developing world. A first-order Markov occurrence model with a mixed exponential amount model is selected as the best option for unconditioned Markov models. However, there is no clear advantage in selecting Markov models over the LARS-WG model for DRWH in West Africa, with each model having distinct strengths and weaknesses. A multi-model approach is used in assessing DRWH in the region to illustrate the variability associated with the rainfall models. It is clear DRWH can be successfully used as a water enhancement mechanism in West Africa for certain times of the year. A 200 L drum storage capacity could potentially optimize these simple, small roof area systems for many locations in the region.

  10. Sorghum Quality, Organic Matter Amendments, and Health: Farmers' Perception in Burkina Faso, West Africa

    NARCIS (Netherlands)

    Traore, K.; Stroosnijder, L.

    2005-01-01

    In West Africa, many people suffer from micronutrient deficiencies. Current interventions have low chances of succeeding. Therefore, a food chain approach including local practices is proposed. This article takes local ecological, cultural, and socio-economic aspects into account through a household

  11. Ebola Virus RNA Stability in Human Blood and Urine in West Africa's Environmental Conditions.

    Science.gov (United States)

    Janvier, Frédéric; Delaune, Deborah; Poyot, Thomas; Valade, Eric; Mérens, Audrey; Rollin, Pierre E; Foissaud, Vincent

    2016-02-01

    We evaluated RNA stability of Ebola virus in EDTA blood and urine samples collected from infected patients and stored in West Africa's environmental conditions. In blood, RNA was stable for at least 18 days when initial cycle threshold values were <30, but in urine, RNA degradation occurred more quickly.

  12. Education and Economics in West Africa: From Unwritten Languages to the Internet

    Science.gov (United States)

    Alibrandi, Marsha; Bull, Prince Hycy

    2005-01-01

    Global distribution of West African goods--coffee, chocolate, gold, diamonds (and at one time, ivory)--has linked this region to the outside world for centuries, yet its development remains slow. Not simply the ancestral home of humankind, Africa's western legacies include colonization, partition, and loss of untold millions to slavery and wars of…

  13. A contribution to the knowledge of non-marine Mollusca of South West Africa

    NARCIS (Netherlands)

    Bruggen, van A.C.

    1970-01-01

    The moment to collate scattered notes on South West African non-marine molluscs arrived last year when Mr. B. H. Lamoral of the Natal Museum, Pietermaritzburg (South Africa), entrusted the present author with the study of material obtained during a Council of Scientific and Industrial Research (C.S.

  14. Soil quality improvement for crop production in semi-arid West Africa

    NARCIS (Netherlands)

    Ouédraogo, E.

    2004-01-01

    Soil quality maintenance and crop production improvement in semi-arid West Africa require appropriate cropping technologies, which are ecologically sound and economically viable. Thus, on-farm and on-station experiments have been carried out on the central plateau and in the south of Burkina Faso Th

  15. Epidemiological features and trends of Ebola virus disease in West Africa

    Directory of Open Access Journals (Sweden)

    Ligui Wang

    2015-09-01

    Full Text Available According to a World Health Organization report, the epidemiological features of Ebola virus disease (EVD have changed significantly in West Africa. In this study, the new epidemiological features and prevalence trends for EVD in Guinea, Liberia, and Sierra Leone are described. It was predicted that the Ebola outbreak would end in June 2015.

  16. Simulating malaria transmission in the current and future climate of West Africa

    Science.gov (United States)

    Yamana, T. K.; Bomblies, A.; Eltahir, E. A. B.

    2015-12-01

    Malaria transmission in West Africa is closely tied to climate, as rain fed water pools provide breeding habitat for the anopheles mosquito vector, and temperature affects the mosquito's ability to spread disease. We present results of a highly detailed, spatially explicit mechanistic modelling study exploring the relationships between the environment and malaria in the current and future climate of West Africa. A mechanistic model of human immunity was incorporated into an existing agent-based model of malaria transmission, allowing us to move beyond entomological measures such as mosquito density and vectorial capacity to analyzing the prevalence of the malaria parasite within human populations. The result is a novel modelling tool that mechanistically simulates all of the key processes linking environment to malaria transmission. Simulations were conducted across climate zones in West Africa, linking temperature and rainfall to entomological and epidemiological variables with a focus on nonlinearities due to threshold effects and interannual variability. Comparisons to observations from the region confirmed that the model provides a reasonable representation of the entomological and epidemiological conditions in this region. We used the predictions of future climate from the most credible CMIP5 climate models to predict the change in frequency and severity of malaria epidemics in West Africa as a result of climate change.

  17. Adolescent and Adult Reasoning about Gender Roles and Fairness in Benin, West Africa

    Science.gov (United States)

    Conry-Murray, Clare

    2009-01-01

    This study examined reasoning about gender roles in a traditional society in Benin, West Africa. Ninety-seven male and female adolescents and adults evaluated conflicts between a husband and a wife over gender norms to determine whether gender norms, are judged to be moral or conventional. Although most attributed decision-making power to the…

  18. Alien Planorbid (Mollusca, Gastropoda Pulmonata) from South West Africa erroneously recorded as Biomphalaria Pfeifferi

    NARCIS (Netherlands)

    Bruggen, van A.C.

    1974-01-01

    In 1970 I published a record of the freshwater snail Biomphalaria pfeifferi (Krauss, 1848) (fam. Planorbidae) for South West Africa: "Sandamap Farm, Spitzkoppe" (Van Bruggen, 1970: 45, figs. 1-13). Dr. D. S. Brown of the Medical Research Council (London) kindly drew my attention to the fact that jud

  19. Termite diversity across an anthropogenic disturbance gradient in the humid forest zone of West Africa

    NARCIS (Netherlands)

    Eggleton, P.; Bignell, D.E.; Hauser, S.; Dibog, L.; Norgrove, L.; Madong, B.

    2002-01-01

    Data are presented for termite assemblages across an anthropogenic disturbance gradient in the humid forest zone of West and Central Africa. Sampling was by standardised 100 mx2 m transects in: primary forest, several ages of regenerating forest, agroforestry plots, short fallows, mixed food crop fi

  20. Policy Review on Adult Learning: The Adult Non-Formal Education Policy of Mali, West Africa

    Science.gov (United States)

    Gadio, Moussa

    2011-01-01

    This article focuses on the issue of policy development for adult learning in Mali, West Africa. On January 2007, the Malian government adopted the "Adult Non-formal Education Policy Document," which was intended to regulate the adult learning sector and federate the actions of policy makers, adult education providers, and adult…

  1. Regional vegetation water effects on satellite soil moisture estimations for West Africa

    NARCIS (Netherlands)

    Friesen, J.C.

    2008-01-01

    Soil moisture information is a vital parameter for water resources planning and food production. In particular for West Africa, where income largely depends on rainfed agriculture, reliable information on available soil water is required for modeling and prediction. Over large areas and, specificall

  2. The current capacity for training in public health nutrition in West Africa

    NARCIS (Netherlands)

    Pepping, F.

    2010-01-01

    This article is based on a paper prepared for the Workshop on Establishing a Regional Institute for Public Health Nutrition Research and Training in West Africa, convened in Dakar, Senegal, 26-28 March, 2009. Information was gathered mainly prior to this workshop; several responses, however, came in

  3. Lassa fever in West Africa: evidence for an expanded region of endemicity.

    Science.gov (United States)

    Sogoba, N; Feldmann, H; Safronetz, D

    2012-09-01

    Lassa virus (LASV) is endemic in Sierra Leone, Guinea and Liberia (known as the Mano River region) and Nigeria and Lassa fever cases from these countries are being reported annually. Recent investigations have found evidence for an expanded endemicity zone between the two known Lassa endemic regions indicating that LASV is more widely distributed throughout the Tropical Wooded Savanna ecozone in West Africa.

  4. Formalisation of charcoal value chains and livelihood outcomes in Central- and West Africa

    NARCIS (Netherlands)

    Schure, J.M.; Ingram, V.J.; Sakho-Jimbira, M.S.; Levang, P.; Wiersum, K.F.

    2013-01-01

    This paper examines the link between formalisation of charcoal institutions and livelihoodoutcomes in Central- and WestAfrica. The woodfuel trade generally commenced informally, little controlled by legal or bureaucratic means. Developing formal institutions is often considered as a way of managing

  5. Formalisation of charcoal value chains and livelihood outcomes in Central- and West Africa

    NARCIS (Netherlands)

    Schure, J.; Ingram, V.; Sakho-Jimbira, M.S.; Levang, P.; Wiersum, K.F.

    2013-01-01

    This paper examines the link between formalisation of charcoal institutions and livelihood outcomes in Central- and West Africa. The woodfuel trade generally commenced informally, little controlled by legal or bureaucratic means. Developing formal institutions is often considered as a way of managin

  6. Climate factors play a limited role for past adaptation strategies in West Africa

    DEFF Research Database (Denmark)

    Mertz, Ole; Mbow, Cheikh; Nielsen, Jonas Østergaard;

    2010-01-01

    The Sudano-Sahelian zone of West Africa has experienced recurrent droughts since the mid-1970s and today there is considerable concern for how this region will be able to adapt to future climate change. To develop well targeted adaptation strategies, the relative importance of climate factors...... to be reflected in national adaptation strategies in the region....

  7. Termite- and mulch-mediated rehabilitation of vegetation on crusted soil in West Africa

    NARCIS (Netherlands)

    Mando, A.; Brussaard, L.; Stroosnijder, L.

    1999-01-01

    The rehabilitation of vegetation on structurally crusted soils by triggering termite activity through mulch was studied on three soil types in northern Burkina Faso, West Africa. A split-plot design was used in a fenced environment for the experiment. Insecticide (Dieldrin) was used at a rate of 500

  8. Food insecurity, soil degradation and agricultural markets in West Africa: why current policy approaches fail

    NARCIS (Netherlands)

    Koning, N.B.J.; Heerink, N.; Kauffman, S.

    2001-01-01

    The agricultural sector in West Africa is not at present capable of meeting the growing demand for food for its population and of reversing unfavourable trends in soil degradation. We argue that integrated soil management is an essential condition for sustainable agricultural development in the many

  9. Satellite-Based actual evapotranspiration over drying semiarid terrain in West-Africa

    NARCIS (Netherlands)

    Schuttemeyer, D.; Schillings, Ch.; Moene, A.F.; Bruin, de H.A.R.

    2007-01-01

    A simple satellite-based algorithm for estimating actual evaporation based on Makkink¿s equation is applied to a seasonal cycle in 2002 at three test sites in Ghana, West Africa: at a location in the humid tropical southern region and two in the drier northern region. The required input for the algo

  10. Life in Sierra Leone, West Africa. A Teaching Unit.

    Science.gov (United States)

    Corby, Richard A.

    This unit is designed for students in grades 6-12. The unit provides an introduction to Sierra Leone and the continent of Africa through basic concepts and a conceptual framework for learning. The unit is divided into 17 activities. Activities include: (1) "Stereotypes and Myths about African and Africans"; (2) "The Manding Name…

  11. The Suppression of Internal Unrest in South West Africa (Namibia 1921–1933

    Directory of Open Access Journals (Sweden)

    Andries M. Fokkens

    2013-02-01

    Full Text Available In 1915, the Union of South Africa was requested to administrate South West Africa (SWA (today Namibia on behalf of the British Crown and approved the South West Africa Mandate.  The policies of the Union strongly influenced the administration of SWA, and the administration met with indigenous opposition discontent with the maltreatment.  An attitude of master and servant was prevalent in the mandated territory and the maltreatment of the indigenous people in the mandated territory, racial prejudice, double standards in executing branding laws, enforced indentured labour, dog and hut tax were some of the grievances that the Bondelswarts, the Rehoboth Basters and the Ukuambi had against the SWA Administration.  The Administration perceived these actions as internal unrest and subdued it using police and military resources. Suppressing unrest through force was part of the military policing tradition prevalent in Southern Africa and abroad during the colonial era.  The tactical deployment of ground forces in conjunction with aircraft was an innovation that transformed future operations in SWA between the suppression of the Bondelswarts and the actions against Chief Ipumbu. This article discusses the utilisation of the Union Defence Force (UDF and South West Africa Forces against indigenous people of South West Africa between the two world wars focusing on three incidents over the period 1922 to 1932.  Tactical deployments of ground forces and the application of air power in support of ground forces to suppress internal unrest are explained and discussed.  These discussions provide the military historian with salient facts on physical conditions encountered, the tactics employed and the role of a new weapon system, aircraft, yet to be fully understood in its role as a force multiplier.

  12. Virtual Reference Service in Academic Libraries in West Africa

    Science.gov (United States)

    Sekyere, Kwabena

    2011-01-01

    As technology continues to advance, libraries in Europe and America continue to improve upon their virtual reference services by employing new Web technologies and applying them to existing services. West African academic libraries have begun providing resources electronically to their users but still typically lag behind in the services they…

  13. Forest climbing plants of West Africa: diversity, ecology and management

    NARCIS (Netherlands)

    Bongers, F.J.J.M.; Parren, M.P.E.; Traoré, D.

    2005-01-01

    Climbing plants, including lianas, represent a fascinating component of the ecology of tropical forests. This book focuses on the climbing plants of West African forests. Based on original research, it presents information on the flora (including a checklist), diversity (with overviews at several le

  14. Influence of Madden-Julian Oscillation (MJO) on Rainfall Variability over West Africa at Intraseasonal Timescale

    Science.gov (United States)

    Niang, C.

    2015-12-01

    Intraseasonal variability of rainfall over West Africa plays a significant role in the economy of the region and is highly linked to agriculture and water resources. This research study aims to investigate the relationship between Madden Julian Oscillation (MJO) and rainfall over West Africa during the boreal summer in the the state-of-the-art Atmospheric Model Intercomparison Project (AMIP) type simulations performed by Atmosphere General Circulation Models (GCMs) forced with prescribed Sea Surface Temperature (SST). It aims to determine the impact of MJO on rainfall and convection over West Africa and identify the dynamical processes which are involved in the state-of-the-art climate simulations. The simulations show in general good skills in capturing its main characteristics as well as its influence on rainfall over West Africa. On the global scale, most models simulated an eastward spatio-temporal propagation of enhanced and suppressed convection similar to the observed. However, over West Africa the MJO signal is weak in few of the models although there is a good coherence in the eastward propagation. The influence on rainfall is well captured in both Sahel and Guinea regions thereby adequately producing the transition between positive and negative rainfall anomalies through the different phases as seen in the observation. Furthermore, the results show that strong active convective phase is clearly associated with the African Easterly Jet (AEJ) but the weak convective phase is associated with a much weaker AEJ particularly over coastal Ghana. In assessing the mechanisms which are involved in the above impacts the convectively equatorial coupled waves (CCEW) are analysed separately. The analysis of the longitudinal propagation of zonal wind at 850hPa and outgoing longwave radiation (OLR) shows that the CCEW are very weak and their extention are very limited beyong West African region. It was found that the westward coupled equatorial Rossby waves are needed to

  15. Access to diagnostic tests and essential medicines for cardiovascular diseases and diabetes care: cost, availability and affordability in the West Region of Cameroon.

    Directory of Open Access Journals (Sweden)

    Ahmadou M Jingi

    Full Text Available To assess the availability and affordability of medicines and routine tests for cardiovascular disease (CVD and diabetes in the West region of Cameroon, a low-income setting.A survey was conducted on the availability and cost of twelve routine tests and twenty medicines for CVD and diabetes in eight health districts (four urban and four rural covering over 60% of the population of the region (1.8 million. We analyzed the percentage of tests and medicines available, the median price against the international reference price (median price ratio for the medicines, and affordability in terms of the number of days' wages it would cost the lowest-paid unskilled government worker for initial investigation tests and procurement for one month of treatment.The availability of tests varied between 10% for the ECG to 100% for the fasting blood sugar. The average cost for the initial investigation using the minimum tests cost 29.76 days' wages. The availability of medicines varied from 36.4% to 59.1% in urban and from 9.1% to 50% in rural settings. Only metformin and benzathine-benzylpenicilline had a median price ratio of ≤ 1.5, with statins being largely unaffordable (at least 30.51 days' wages. One month of combination treatment for coronary heart disease costs at least 40.87 days' wages.The investigation and management of patients with medium-to-high cardiovascular risk remains largely unavailable and unaffordable in this setting. An effective non-communicable disease program should lay emphasis on primary prevention, and improve affordable access to essential medicines in public outlets.

  16. Hydrogeochemistry and quality of surface water and groundwater in the vicinity of Lake Monoun, West Cameroon: approach from multivariate statistical analysis and stable isotopic characterization.

    Science.gov (United States)

    Kamtchueng, Brice T; Fantong, Wilson Y; Wirmvem, Mengnjo J; Tiodjio, Rosine E; Takounjou, Alain F; Ndam Ngoupayou, Jules R; Kusakabe, Minoru; Zhang, Jing; Ohba, Takeshi; Tanyileke, Gregory; Hell, Joseph V; Ueda, Akira

    2016-09-01

    With the use of conventional hydrogeochemical techniques, multivariate statistical analysis, and stable isotope approaches, this paper investigates for the first time surface water and groundwater from the surrounding areas of Lake Monoun (LM), West Cameroon. The results reveal that waters are generally slightly acidic to neutral. The relative abundance of major dissolved species are Ca(2+) > Mg(2+) > Na(+) > K(+) for cations and HCO3 (-) ≫ NO3 (-) > Cl(-) > SO4 (2-) for anions. The main water type is Ca-Mg-HCO3. Observed salinity is related to water-rock interaction, ion exchange process, and anthropogenic activities. Nitrate and chloride have been identified as the most common pollutants. These pollutants are attributed to the chlorination of wells and leaching from pit latrines and refuse dumps. The stable isotopic compositions in the investigated water sources suggest evidence of evaporation before recharge. Four major groups of waters were identified by salinity and NO3 concentrations using the Q-mode hierarchical cluster analysis (HCA). Consistent with the isotopic results, group 1 represents fresh unpolluted water occurring near the recharge zone in the general flow regime; groups 2 and 3 are mixed water whose composition is controlled by both weathering of rock-forming minerals and anthropogenic activities; group 4 represents water under high vulnerability of anthropogenic pollution. Moreover, the isotopic results and the HCA showed that the CO2-rich bottom water of LM belongs to an isolated hydrological system within the Foumbot plain. Except for some springs, groundwater water in the area is inappropriate for drinking and domestic purposes but good to excellent for irrigation.

  17. Illicit Drug Trafficking in West Africa -- Primary Surveillance Radar Introduction

    Science.gov (United States)

    2012-03-22

    rich-quick message and a devaluation of traditional values which have always kept these societies cohesive and united. This tension breeds violence...commodities, such as kola and cannabis . Imported American rum, French brandy and Dutch gin was also traded along these coasts for more than 500 5 years...Kola stimulant, cannabis and alcohol were all legally traded between Europe, the Middle East and the Sahara. Given West Africa’s long history of

  18. Assessment of future streamflow changes in major rivers of West Africa

    Science.gov (United States)

    Roudier, Philippe; Rojas, Rodrigo; Bisselink, Bernard; Feyen, Luc

    2013-04-01

    Although being one of the most vulnerable regions of the world to climate change, impact studies in West Africa, especially concerning water resources, are still scarce compared to other regions such as Europe, North-America or Asia. Therefore, we investigate in this study how climate change may affect the main rivers of West Africa (Niger, Volta, Senegal) using the global LISFLOOD model. This hydrological rainfall-runoff model, extensively used for pan-European assessments, has been recently set up and calibrated for Africa, allowing such impact analysis. Here, LISFLOOD is set up on a 0.1*0.1 degree grid for the period 1991-2050. Quantifying the uncertainty in climate impact studies is now a fundamental task, especially in West Africa where the agreement among rainfall projections is low. We therefore employ an ensemble of climate experiments originating from 8 different GCM/RCM combinations obtained from the EU FP6 ENSEMBLES project (SRES A1B scenario). Prior to forcing LISFLOOD, bias in the precipitation and temperature fields (Tmin, Tavg and Tmax) is removed with a quantile mapping method using as target the WATCH Forcing Data. In order to take into account the high population growth in West Africa we also account for projected changes in water use. Results first focus on changes in average streamflow conditions and how these changes affect water availability, expressed by the Water Exploitation Index. Second, and as underlined by the recent SREX IPCC report (2012), we show the impacts on extreme events (droughts and floods) using relevant indices such as the 100-year return period flood.

  19. Multimodel ensemble simulations of present and future climates over West Africa: Impacts of vegetation dynamics

    Science.gov (United States)

    Erfanian, Amir; Wang, Guiling; Yu, Miao; Anyah, Richard

    2016-09-01

    In this study, we take an ensemble modeling approach using the regional climate model RegCM4.3.4-CLM-CN-DV (RCM) to study the impact of including vegetation dynamics on model performance in simulating present-day climate and on future climate projections over West Africa. The ensemble consists of four global climate models (GCMs) as lateral boundary conditions for the RCM, and simulations with both static and dynamic vegetation are conducted. The results demonstrate substantial sensitivity of the simulated precipitation, evapotranspiration, and soil moisture to vegetation representation. Although including dynamic vegetation in the model eliminates potential inconsistencies between surface climate and the bioclimatic requirements of the prescribed vegetation, it enhances model biases causing climate drift. For present-day climate, the ensemble average generally outperforms individual members due to cancelation of model biases. For future changes, although the original GCMs project contradicting future rainfall trends over West Africa, the RCMs-produced trends are generally consistent. The multimodel ensemble projects significant decreases of rainfall over a major portion of West Africa and significant increases over eastern Sahel and East Africa. Projected future changes of evapotranspiration and soil moisture are consistent with those of precipitation, with significant decreases (increases) for western (eastern) Sahel. Accounting for vegetation-climate interactions has localized but significant impacts on projected future changes of precipitation, with a wet signal over a belt of projected increase of woody vegetation cover; the impact on the projected future changes of evapotranspiration and soil moisture over west and central Africa is much more profound.

  20. Drought modes in West Africa and how well CORDEX RCMs simulate them

    Science.gov (United States)

    Diasso, Ulrich; Abiodun, Babatunde J.

    2015-12-01

    This study presents the spatial-temporal structure of droughts in West Africa and evaluates the capability of CORDEX regional climate models in simulating the droughts. The study characterize droughts with the standardized evapo-transpiration index (SPEI) computed using the monthly rainfall and temperature data from the Climatic Research Unit (CRU) and CORDEX models simulation datasets. To obtain the spatial-temporal structure of the droughts, we applied the principal component analysis on the observed and simulated SPEIs and retained the first four principal factors as the leading drought modes over West Africa. The relationship between the drought modes and atmospheric teleconnections was studied using wavelet coherence analysis, while the ability of the CORDEX models to simulate the drought modes was quantified with correlation analysis. The analysis of the relationship between drought modes and atmospheric teleconnections is based on SPEI from observation dataset (CRU). The study shows that about 60 % of spatial-temporal variability in SPEI over West Africa can be grouped into four drought modes. The first drought mode features drought over east Sahel, the second over west Sahel, the third over the Savanna, and the fourth over the Guinea coast. Each drought mode is linked to sea surface temperature anomalies (SSTAs) over tropical areas of Pacific, Atlantic, and Indian Oceans. Most CORDEX models reproduce at least two of the drought modes, but only two models (REMO and CNRM) reproduce all the four drought modes. REMO and WRF give the best simulation of the seasonal variation of the drought mode over the Sahel in March-May and June-August seasons, while CNRM gives the best simulation of seasonal variation in the drought pattern over the Savanna. Results of this study may guide in selecting appropriate CORDEX models for seasonal prediction of droughts and for downscaling projected impacts of global warming on droughts in West Africa.

  1. Cocoa Intensification Scenarios and Their Predicted Impact on CO2 Emissions, Biodiversity Conservation, and Rural Livelihoods in the Guinea Rain Forest of West Africa

    Science.gov (United States)

    Gockowski, Jim; Sonwa, Denis

    2011-08-01

    The Guinean rain forest (GRF) of West Africa, identified over 20 years ago as a global biodiversity hotspot, had reduced to 113,000 km2 at the start of the new millennium which was 18% of its original area. The principal driver of this environmental change has been the expansion of extensive smallholder agriculture. From 1988 to 2007, the area harvested in the GRF by smallholders of cocoa, cassava, and oil palm increased by 68,000 km2. Field results suggest a high potential for significantly increasing crop yields through increased application of seed-fertilizer technologies. Analyzing land-use change scenarios, it was estimated that had intensified cocoa technology, already developed in the 1960s, been pursued in Cote d'Ivoire, Ghana, Nigeria and Cameroon that over 21,000 km2 of deforestation and forest degradation could have been avoided along with the emission of nearly 1.4 billion t of CO2. Addressing the low productivity of agriculture in the GRF should be one of the principal objectives of REDD climate mitigation programs.

  2. Understanding the nature and threats of drug trafficking to national and regional security in West Africa

    Directory of Open Access Journals (Sweden)

    Kwesi Aning

    2014-02-01

    Full Text Available Several West African states are threatened by increasingly powerful transnational organised criminal networks. Yet, scholarly work on the nature, characteristics and strength of these groups and how their activities threaten states remains sparse, leading to misunderstandings and inadequate appreciation of the precise nature of the threats they pose to West Africa. This paper seeks to fill these lacunae in our knowledge. It focuses on the nexus between drugs, crime and terrorism. It argues that, the financial spin-offs from criminal activities contribute to the development of opportunistic relationships between criminals and extremist groups that threatens West Africa’s fragile states. The analyses are based on evidence from several West African states, but employ the ongoing crisis in the Sahel, particularly Mali, as an empirical case, to demonstrate how ‘profitable collusion’ among different actors permits hollow states to become edifices that allows corruption, criminality and impunity to flourish.

  3. Rotavirus disease in Guinea-Bissau, West Africa: a review of longitudinal community and hospital studies

    DEFF Research Database (Denmark)

    Fischer, Thea Kølsen; Aaby, Peter; Mølbak, Kåre;

    2010-01-01

    Rotavirus is one of the most common causes of childhood diarrheal disease and deaths in sub-Saharan Africa. This article reviews community- and hospital-based surveillance of rotavirus disease in Bissau, Guinea-Bissau, West Africa. Here, rotavirus infections exhibit a seasonal pattern, with annual...... epidemics occurring during the relatively dry and cooler months, from January to April, and few cases registered from May to December. Most children (74%) experience their first infection before the age of 2 years, and rotavirus has been identified as the most pathogenic of all diarrheal agents during 2...

  4. Insecticide dissipation from soil and plant surfaces in tropical horticulture of southern Benin, West Africa.

    Science.gov (United States)

    Rosendahl, Ingrid; Laabs, Volker; Atcha-Ahowé, Cyrien; James, Braima; Amelung, Wulf

    2009-06-01

    In Sub-Saharan Africa, horticulture provides livelihood opportunities for millions of people, especially in urban and peri-urban areas. Although the vegetable agroecosystems are often characterized by intensive pesticide use, risks resulting therefrom are largely unknown under tropical horticultural conditions. The objective of this study therefore was to study the fate of pesticides in two representative horticultural soils (Acrisol and Arenosol) and plants (Solanum macrocarpon L.) after field application and thus to gain first insight on environmental persistence and dispersion of typical insecticides used in vegetable horticulture in Benin, West Africa. On plant surfaces, dissipation was rapid with half lives ranging from 2 to 87 h (alpha-endosulfan tropical environments.

  5. Reconstructing C3 and C4 vegetation cover using n-alkane carbon isotope ratios in recent lake sediments from Cameroon, Western Central Africa

    Science.gov (United States)

    Garcin, Yannick; Schefuß, Enno; Schwab, Valérie F.; Garreta, Vincent; Gleixner, Gerd; Vincens, Annie; Todou, Gilbert; Séné, Olivier; Onana, Jean-Michel; Achoundong, Gaston; Sachse, Dirk

    2014-10-01

    Trees and shrubs in tropical Africa use the C3 cycle as a carbon fixation pathway during photosynthesis, while grasses and sedges mostly use the C4 cycle. Leaf-wax lipids from sedimentary archives such as the long-chain n-alkanes (e.g., n-C27 to n-C33) inherit carbon isotope ratios that are representative of the carbon fixation pathway. Therefore, n-alkane δ13C values are often used to reconstruct past C3/C4 composition of vegetation, assuming that the relative proportions of C3 and C4 leaf waxes reflect the relative proportions of C3 and C4 plants. We have compared the δ13C values of n-alkanes from modern C3 and C4 plants with previously published values from recent lake sediments and provide a framework for estimating the fractional contribution (areal-based) of C3 vegetation cover (fC3) represented by these sedimentary archives. Samples were collected in Cameroon, across a latitudinal transect that accommodates a wide range of climate zones and vegetation types, as reflected in the progressive northward replacement of C3-dominated rain forest by C4-dominated savanna. The C3 plants analysed were characterised by substantially higher abundances of n-C29 alkanes and by substantially lower abundances of n-C33 alkanes than the C4 plants. Furthermore, the sedimentary δ13C values of n-C29 and n-C31 alkanes from recent lake sediments in Cameroon (-37.4‰ to -26.5‰) were generally within the range of δ13C values for C3 plants, even when from sites where C4 plants dominated the catchment vegetation. In such cases simple linear mixing models fail to accurately reconstruct the relative proportions of C3 and C4 vegetation cover when using the δ13C values of sedimentary n-alkanes, overestimating the proportion of C3 vegetation, likely as a consequence of the differences in plant wax production, preservation, transport, and/or deposition between C3 and C4 plants. We therefore tested a set of non-linear binary mixing models using δ13C values from both C3 and C4

  6. The current capacity for training in public health nutrition in West Africa.

    Science.gov (United States)

    Pepping, Fré

    2010-01-01

    This article is based on a paper prepared for the Workshop on Establishing a Regional Institute for Public Health Nutrition Research and Training in West Africa, convened in Dakar, Senegal, 26-28 March, 2009. Information was gathered mainly prior to this workshop; several responses, however, came in after the workshop and these have been included in the current paper. In completion of the article use was made of the views and opinions as expressed during this workshop. Objectives were to provide background information on academic programmes (undergraduate and graduate) and research institutions with a focus on human nutrition in West Africa, to describe the importance of foreign nutrition training programmes for West African students and to detail existing nutrition training activities currently in the region. Data were obtained from a survey of 15 UNICEF country offices in the West African region, previously published reports, United Nations University/International Union of Nutrition Sciences capacity development activities 1996-2009, personal communications and websites of relevant African institutions. Results indicate that West African nutrition academic programmes and research institutes do not adequately meet the demand for nutritionists and technical services in the region. Exceptions seem to be Benin, Ghana and Nigeria. Diploma courses and other short courses have been an important means of attracting people from a variety of disciplines to nutrition. A well-equipped regional institute could directly and indirectly bolster nutrition capacity in the region. To meet the regional nutrition research and training needs in West Africa, it is not necessary to make a choice between creating a new regional institution vs. expanding existing national institutions. Based on solid capacity development principles, both options need action.

  7. West Africa [in "State of the Climate in 2014"

    Energy Technology Data Exchange (ETDEWEB)

    Hagos, Samson M.; Ijampy, James A.; Sima, Fatou; Francis, Sabastine

    2015-08-06

    This chapter provides summaries of the 2014 temperature and precipitation conditions across seven broad regions: North America, Central America and the Caribbean, South America, Africa, Europe, Asia, and Oceania. In most cases, summaries of notable weather events are also included. Local scientists provided the annual summary for their respective regions and, unless otherwise noted, the source of the data used is typically the agency affiliated with the authors. Please note that different nations, even within the same section, may use unique periods to define their normals. Section introductions will typically define the prevailing practices for that section, and exceptions will be noted within the text. In a similar way, many contributing authors use languages other than English as their primary professional language. To minimize additional loss of fidelity through re-interpretation after translation, editors have been conservative and careful to preserve the voice of the author. In some cases, this may result in abrupt transitions in style from section to section.

  8. Education and Indigenous Knowledge in Africa: Traditional Bonesetting and Orthopaedic Medicine in West Africa

    Science.gov (United States)

    Ezeanya, Chika A.

    The underlying philosophy of education in contemporary Africa has been established to be alien, and detached from the indigenous knowledge of the people. Modern day formal education in sub-Saharan Africa came about, for the most part, as a result of missionary activities and colonial efforts of Europe. The education bequeathed to Africa was, therefore, fundamentally European in paradigm and lacking in authenticity. The end of colonialism across sub-Saharan Africa did not herald any tangible transformation in the curriculum of study. Education in Africa is still dependent on foreign input for sustainability, thereby stifling research, creativity and innovation. Sustainable development is founded on indigenous knowledge. When such grassroots knowledge assumes the foundation of learning, home-grown development is easily fostered in all sectors of a national economy. In the field of medicine, indigenous knowledge of healing has been considered unscientific by western biomedical practitioners. Since the days of the missionaries, many Africans have considered indigenous medicine to be fetish; the Christian converts would not be associated with its practice and patronage. However, traditional bonesetting has been proven to be highly efficacious with little supernatural content, it continues to attract huge patronage from Africans, cutting across social and religious boundaries. This study attempts an exploration of the disconnect between indigenous knowledge, practices and learning, on the one hand, and formal education in Africa, on the other. With a focus on traditional bonesetting, the study seeks to determine why that branch of indigenous medicine attracts huge patronage, but is granted very little recognition by modern orthopaedic medical education.

  9. Secondary Organic Aerosol from biogenic VOCs over West Africa during AMMA

    Directory of Open Access Journals (Sweden)

    G. Capes

    2009-01-01

    Full Text Available This paper presents measurements of organic aerosols above subtropical West Africa during the wet season using data from the UK Facility for Airborne Atmospheric Measurements (FAAM aircraft. Measurements of biogenic volatile organic compounds (BVOC at low altitudes over these subtropical forests were made during the African Monsoon Multidisciplinary Analysis (AMMA field experiment during July and August 2006 mainly above Benin, Nigeria and Niger. Data from an Aerodyne Quadrupole Aerosol Mass Spectrometer show a median organic aerosol loading of 1.08 μg m−3 over tropical West Africa, which represents the first regionally averaged assessment of organic aerosol mass (OM in this region during the wet season. This is in good agreement with predictions based on aerosol yields from isoprene and monoterpenes during chamber studies and model predictions based on partitioning schemes, contrasting markedly with the large under representations of OM in similar models when compared with data from mid latitudes.

  10. Cross-border Co-operation and Policy Networks in West Africa

    DEFF Research Database (Denmark)

    Trémolières, Marie; Walther, Olivier

    policy networks, showing that borders have notable and diverse impacts on exchanges of information and the relative power of networks. The report then analyses a range of regional indicators of co-operation potential, visually demonstrating that borders can also affect the ability of sub-regions within......This publication examines how policy actors involved in cross-border co-operation contribute to the regional integration process in West Africa. It uses a pioneering methodology, known as social network analysis, to visualise the formal and informal relationships between actors involved in cross-border...... West Africa to develop cross-border initiatives in a number of ways. Combining these two analyses with the perceptions of regional policy makers as to which border areas they consider as priorities for regional integration, the publication concludes with the analytical foundations for more effective...

  11. Disease patterns and causes of death of hospitalized HIV-positive adults in West Africa

    DEFF Research Database (Denmark)

    Lewden, Charlotte; Drabo, Youssoufou J; Zannou, Djimon M;

    2014-01-01

    OBJECTIVE: We aimed to describe the morbidity and mortality patterns in HIV-positive adults hospitalized in West Africa. METHOD: We conducted a six-month prospective multicentre survey within the IeDEA West Africa collaboration in six adult medical wards of teaching hospitals in Abidjan...... definitions. Factors associated with in-hospital mortality were studied with a logistic regression model. RESULTS: Among 823 hospitalized HIV-positive adults (median age 40 years, 58% women), 24% discovered their HIV infection during the hospitalization, median CD4 count was 75/mm(3) (IQR: 25-177) and 48% had......%), cerebral toxoplasmosis (10%), cryptococcosis (9%) and sepsis (7%). Older age, clinical WHO stage 3 and 4, low CD4 count, and AIDS-defining infectious diagnoses were associated with hospital fatality. CONCLUSIONS: AIDS-defining conditions, primarily tuberculosis, and bacterial infections were the most...

  12. Dirhinus giffardii (Hymenoptera: Chalcididae, parasitoid affecting Black Soldier Fly production systems in West Africa

    Directory of Open Access Journals (Sweden)

    Emilie Devic

    2015-12-01

    Full Text Available Interest for insect farming is currently growing globally. Conditions in West Africa appear suitable for developing such farming systems that can benefit communities by improving livelihoods, food and feed security or sanitation. In Ghana and Mali, the Black Soldier Fly (Hermetia illucens Linnaeus, 1758 is being produced for waste recycling and animal feed. In a two stages process (egg and larvae production, egg production was hampered by a pupal parasitoid, Dirhinus giffardii Silvestri, 1913 (Hymenoptera: Chalcididae, which reduced future broodstock by almost 72%. This is the first time D. giffardii is reported as a parasitoid of H. illucens pupae and one of the first reports of parasitism in this commercially important fly species. The introduction of precautionary measures is highly recommended for the success of H. illucens production systems in West Africa.

  13. The possible role of local air pollution in climate change in West Africa

    Science.gov (United States)

    Knippertz, Peter; Evans, Mat J.; Field, Paul R.; Fink, Andreas H.; Liousse, Catherine; Marsham, John H.

    2015-09-01

    The climate of West Africa is characterized by a sensitive monsoon system that is associated with marked natural precipitation variability. This region has been and is projected to be subject to substantial global and regional-scale changes including greenhouse-gas-induced warming and sea-level rise, land-use and land-cover change, and substantial biomass burning. We argue that more attention should be paid to rapidly increasing air pollution over the explosively growing cities of West Africa, as experiences from other regions suggest that this can alter regional climate through the influences of aerosols on clouds and radiation, and will also affect human health and food security. We need better observations and models to quantify the magnitude and characteristics of these impacts.

  14. Evaluating the performance of remotely sensed and reanalysed precipitation data over West Africa using HBV light

    Science.gov (United States)

    Jütten, Thomas; Jackisch, Dominik; Diekkrüger, Bernd; Kusche, Jürgen; Eicker, Annette; Springer, Anne

    2016-04-01

    Water is one of the most crucial natural resources in West Africa, where the livelihoods of large parts of the population rely heavily on rain-fed agriculture. Therefore, the modelling of the water balance is an important tool to aid in water resource management. Precipitation is one of most important atmospheric drivers of hydrological models. However, ground-based observation networks are sparse in Western Africa and a further decline in station numbers due to a variety of reasons such as the deterioration of stations or political unrest has been observed in recent years. In ungauged river basins, or basins with insufficiently available precipitation data, several studies have shown that remotely sensed or reanalysed precipitation data may be used to compliment or replace missing information. However, the uncertainties of these datasets over Western Africa are not well examined and a need for further studies is apparent. For validation purposes, precipitation datasets are traditionally compared to in-situ ground measurements. This is not possible in ungauged basins. A new approach to assess the quality of satellite and reanalysis data which is gaining popularity among researchers compares different precipitation datasets using hydrological models. In this so-called hydrological evaluation, ground-truth data is no longer necessary in order to validate a product. The chosen model is calibrated for different precipitation products and the simulated streamflow generated for each product is compared to the measured streamflow. Multiple state of the art satellite and reanalysis precipitation datasets with various spatial resolutions were used in this study, namely: CFSR (0.3125°), CHIRPS (0.05°), CMORPH (0.25°), PERSIANN (0.25°), RFE 2.0 (0.1°), TAMSAT (0.0375°), TRMM 3B42 v7 (0.25°) and TRMM 3B42RT (real time) (0.25°). These datasets were evaluated at the regional as well as local scale using the HBV light conceptual hydrological model for several basins

  15. The Burden of Orphans and Vulnerable Children Due to HIV/AIDS in Cameroon.

    Science.gov (United States)

    Nsagha, Dickson S; Bissek, Anne-Cécile Zk; Nsagha, Sarah M; Assob, Jules-Clement N; Kamga, Henri-Lucien F; Njamnshi, Dora M; Njunda, Anna L; Obama, Marie-Thérèse O; Njamnshi, Alfred K

    2012-01-01

    HIV/AIDS is a major public health problem in Cameroon and Africa, and the challenges of orphans and vulnerable children are a threat to child survival, growth and development. The HIV prevalence in Cameroon was estimated at 5.1% in 2010. The objective of this study was to assess the burden of orphans and vulnerable children due to HIV/AIDS in Cameroon. A structured search to identify publications on orphans and other children made vulnerable by AIDS was carried out. A traditional literature search on google, PubMed and Medline using the keywords: orphans, vulnerable children, HIV/AIDS and Cameroon was conducted to identify potential AIDS orphans publications, we included papers on HIV prevalence in Cameroon, institutional versus integrated care of orphans, burden of children orphaned by AIDS and projections, impact of AIDS orphans on Cameroon, AIDS orphans assisted through the integrated care approach, and comparism of the policies of orphans care in the central African sub-region. We also used our participatory approach working experience with traditional rulers, administrative authorities and health stakeholders in Yaounde I and Yaounde VI Councils, Nanga Eboko Health District, Isangelle and Ekondo Titi Health Areas, Bafaka-Balue, PLAN Cameroon, the Pan African Institute for Development-West Africa, Save the orphans Foundation, Ministry of Social Affairs, and the Ministry of Public Health. Results show that only 9% of all OVC in Cameroon are given any form of support. AIDS death continue to rise in Cameroon. In 1995, 7,900 people died from AIDS in the country; and the annual number rose to 25,000 in 2000. Out of 1,200,000 orphans and vulnerable children in Cameroon in 2010, 300,000(25%) were AIDS orphans. Orphans and the number of children orphaned by AIDS has increased dramatically from 13,000 in 1995 to 304,000 in 2010. By 2020, this number is projected to rise to 350,000. These deaths profoundly affect families, which often are split up and left without any

  16. Understanding changes in terrestrial water storage over West Africa between 2002 and 2014

    Science.gov (United States)

    Ndehedehe, Christopher; Awange, Joseph; Agutu, Nathan; Kuhn, Michael; Heck, Bernhard

    2016-02-01

    With the vast water resources of West Africa coming under threat due to the impacts of climate variability and human influence, the need to understand its terrestrial water storage (TWS) changes becomes very important. Due to the lack of consistent in-situ hydrological data to assist in the monitoring of changes in TWS, this study takes advantage of the Gravity Recovery and Climate Experiment (GRACE) monthly gravity fields to provide estimates of vertically integrated changes in TWS over the period 2002-2014, in addition to satellite altimetry data for the period 1993-2014. In order to understand TWS variability over West Africa, Principal Component Analysis (PCA), a second order statistical technique, and Multiple Linear Regression Analysis (MLRA) are employed. Results show that dominant patterns of GRACE-derived TWS changes are observed mostly in the West Sahel, Guinea Coast, and Middle Belt regions of West Africa. This is probably caused by high precipitation rates at seasonal and inter-annual time scales induced by ocean circulations, altitude and physiographic features. While the linear trend for the spatially averaged GRACE-derived TWS changes over West Africa for the study period shows an increase of 6.85 ± 1.67 mm/yr, the PCA result indicates a significant increase of 20.2 ± 5.78 mm/yr in Guinea, a region with large inter-annual variability in seasonal rainfall, heavy river discharge, and huge groundwater potentials. The increase in GRACE-derived TWS during this period in Guinea, though inconsistent with the lack of a significant positive linear trend in TRMM based precipitation, is attributed to a large water surplus from prolonged wet seasons and lower evapotranspiration rates, leading to an increase in storage and inundated areas over the Guinea region. This increase in storage, which is also the aftermath of cumulative increase in the volume of water not involved in surface runoff, forms the huge freshwater availability in this region. However, the

  17. Checklist of the lizards of Togo (West Africa), with comments on systematics, distribution, ecology, and conservation

    OpenAIRE

    Hoinsoude Segniagbeto, G.; Trape, Jean-François; Afiademanyo, K. M.; Rodel, M. O.; Ohler, A.; Dubois, A.; David, P.; Meirte, D.; Glitho, I. A.; Petrozzi, F.; L. Luiselli

    2015-01-01

    The lizard fauna of Togo, a country situated within a natural gap in the rainforest zone of West Africa, is reviewed and updated. In this article, we summarize all available data on the distribution, ecology, and conservation status of the 43 lizard species of Togo. Species richness is uneven between vegetation zones. The submontane forest (ecological zone IV), despite being the smallest, houses the greatest number of species (n = 27), followed by dry forest (ecological zone II, n = 21). Curr...

  18. Understanding the Root Causes of Military Coups and Governmental Instability in West Africa

    Science.gov (United States)

    2013-12-13

    due to the lack of education of the military with allusion to the subalterns. Facts however show that high ranking officers with noticeable high...education level, organize and execute most of the military coups in West Africa. The low ranking military personnel conduct very few military coups in...vote, the president wins a seven-year term and is eligible for a second term. Leopold Sedar Senghor is the first president of an independent Senegal

  19. Improving regional health care in West Africa using current space systems and technology

    Science.gov (United States)

    Jemison, Mae C.; Thomas, J. S.

    1992-01-01

    This paper discusses the issues involved with establishing an integrated satellite health network in West Africa based on currently available technology. The system proposed makes use of a central national facility capable of transmitting and receiving voice/data and video signals from the entire country. Regional, field and local facilities provides timely epidemiologic information, sharing of medical expertise through telemedical consultations, enhances optimized resource distribution and builds a framework for telecommunications for the entire country.

  20. Agriculture in West Africa in the twenty-first century : climate change and impacts scenarios, and potential for adaptation

    OpenAIRE

    Benjamin Sultan; Marco Gaetani

    2016-01-01

    International audience; West Africa is known to be particularly vulnerable to climate change due to high climate variability, high reliance on rain-fed agriculture and limited economic and institutional capacity to respond to climate variability and change. In this context, better knowledge of how climate will change in West Africa and how such changes will impact crop productivity is crucial to inform policies that may counteract the adverse effects. This review paper provides a comprehensiv...

  1. Climate change unlikely to increase malaria burden in West Africa

    Science.gov (United States)

    Yamana, Teresa K.; Bomblies, Arne; Eltahir, Elfatih A. B.

    2016-11-01

    The impact of climate change on malaria transmission has been hotly debated. Recent conclusions have been drawn using relatively simple biological models and statistical approaches, with inconsistent predictions. Consequently, the Intergovernmental Panel on Climate Change Fifth Assessment Report (IPCC AR5) echoes this uncertainty, with no clear guidance for the impacts of climate change on malaria transmission, yet recognizing a strong association between local climate and malaria. Here, we present results from a decade-long study involving field observations and a sophisticated model simulating village-scale transmission. We drive the malaria model using select climate models that correctly reproduce historical West African climate, and project reduced malaria burden in a western sub-region and insignificant impact in an eastern sub-region. Projected impacts of climate change on malaria transmission in this region are not of serious concern.

  2. Safe and Effective Deployment of Personnel to Support the Ebola Response - West Africa.

    Science.gov (United States)

    Rouse, Edward N; Zarecki, Shauna Mettee; Flowers, Donald; Robinson, Shawn T; Sheridan, Reed J; Goolsby, Gary D; Nemhauser, Jeffrey; Kuwabara, Sachiko

    2016-07-08

    From the initial task of getting "50 deployers within 30 days" into the field to support the 2014-2016 Ebola virus disease (Ebola) epidemic response in West Africa to maintaining well over 200 staff per day in the most affected countries (Guinea, Liberia, and Sierra Leone) during the peak of the response, ensuring the safe and effective deployment of international responders was an unprecedented accomplishment by CDC. Response experiences shared by CDC deployed staff returning from West Africa were quickly incorporated into lessons learned and resulted in new activities to better protect the health, safety, security, and resiliency of responding personnel. Enhanced screening of personnel to better match skill sets and experience with deployment needs was developed as a staffing strategy. The mandatory predeployment briefings were periodically updated with these lessons to ensure that staff were aware of what to expect before, during, and after their deployments. Medical clearance, security awareness, and resiliency programs became a standard part of both predeployment and postdeployment activities. Response experience also led to the identification and provision of more appropriate equipment for the environment. Supporting the social and emotional needs of deployed staff and their families also became an agency focus for care and communication. These enhancements set a precedent as a new standard for future CDC responses, regardless of size or complexity.The activities summarized in this report would not have been possible without collaboration with many U.S and international partners (http://www.cdc.gov/vhf/ebola/outbreaks/2014-west-africa/partners.html).

  3. International Commodity Markets, Local Food Prices and Environment in West Africa

    Science.gov (United States)

    Brown, M. E.; Hintermann, B.; Higgins, N.

    2008-12-01

    The recent massive increase in food and energy prices in the past five years, coupled with the awareness of the long term challenges of climate change to small holder agriculture in Africa has brought the issue of food security for the world's poorest people to the forefront once again. Asymmetric and limited integration of local commodity markets in West Africa highlights the weak position of Africa's rural countries in the face of climate change and demographic expansion. This paper will describe the functioning of local informal food markets in West African over the past twenty years and evaluate the impact of their limited integration with each other and with global commodity markets. Satellite remote sensing of vegetation has been used as a proxy for agricultural production in economic models to improve prediction of large swings in prices from year to year due to differences in supply. As demand increases, improvements in market functioning will be necessary to counter likely increases in production variability. Increasing Africa's stability in the face of climate change will require investment in agricultural production and transportation infrastructure in order to ensure an affordable flow of food to people in these extremely poor, landlocked countries.

  4. Mitochondrial DNA transit between West Asia and North Africa inferred from U6 phylogeography

    Directory of Open Access Journals (Sweden)

    Larruga José M

    2003-10-01

    Full Text Available Abstract Background World-wide phylogeographic distribution of human complete mitochondrial DNA sequences suggested a West Asian origin for the autochthonous North African lineage U6. We report here a more detailed analysis of this lineage, unraveling successive expansions that affected not only Africa but neighboring regions such as the Near East, the Iberian Peninsula and the Canary Islands. Results Divergence times, geographic origin and expansions of the U6 mitochondrial DNA clade, have been deduced from the analysis of 14 complete U6 sequences, and 56 different haplotypes, characterized by hypervariable segment sequences and RFLPs. Conclusions The most probable origin of the proto-U6 lineage was the Near East. Around 30,000 years ago it spread to North Africa where it represents a signature of regional continuity. Subgroup U6a reflects the first African expansion from the Maghrib returning to the east in Paleolithic times. Derivative clade U6a1 signals a posterior movement from East Africa back to the Maghrib and the Near East. This migration coincides with the probable Afroasiatic linguistic expansion. U6b and U6c clades, restricted to West Africa, had more localized expansions. U6b probably reached the Iberian Peninsula during the Capsian diffusion in North Africa. Two autochthonous derivatives of these clades (U6b1 and U6c1 indicate the arrival of North African settlers to the Canarian Archipelago in prehistoric times, most probably due to the Saharan desiccation. The absence of these Canarian lineages nowadays in Africa suggests important demographic movements in the western area of this Continent.

  5. Exon-Enriched Libraries Reveal Large Genic Differences Between Aedes aegypti from Senegal, West Africa, and Populations Outside Africa.

    Science.gov (United States)

    Dickson, Laura B; Campbell, Corey L; Juneja, Punita; Jiggins, Francis M; Sylla, Massamba; Black, William C

    2017-02-09

    Aedes aegypti is one of the most studied mosquito species, and the principal vector of several arboviruses pathogenic to humans. Recently failure to oviposit, low fecundity, and poor egg-to-adult survival were observed when Ae. aegypti from Senegal (SenAae) West Africa were crossed with Ae. aegypti (Aaa) from outside of Africa, and in SenAae intercrosses. Fluorescent in situ hybridization analyses indicated rearrangements on chromosome 1, and pericentric inversions on chromosomes 2 and 3. Herein, high throughput sequencing (HTS) of exon-enriched libraries was used to compare chromosome-wide genetic diversity among Aaa collections from rural Thailand and Mexico, a sylvatic collection from southeastern Senegal (PK10), and an urban collection from western Senegal (Kaolack). Sex-specific polymorphisms were analyzed in Thailand and PK10 to assess genetic differences between sexes. Expected heterozygosity was greatest in SenAae FST distributions of 15,735 genes among all six pairwise comparisons of the four collections indicated that Mexican and Thailand collections are genetically similar, while FST distributions between PK10 and Kaolack were distinct. All four comparisons of SenAae with Aaa indicated extreme differentiation. FST was uniform between sexes across all chromosomes in Thailand, but were different, especially on the sex autosome 1, in PK10. These patterns correlate with the reproductive isolation noted earlier. We hypothesize that cryptic Ae. aegypti taxa may exist in West Africa, and the large genic differences between Aaa and SenAae detected in the present study have accumulated over a long period following the evolution of chromosome rearrangements in allopatric populations that subsequently cause reproductive isolation when these populations became sympatric.

  6. The impact of civil war on forest wildlife in West Africa: Mammals in Gola Forest, Sierra Leone

    NARCIS (Netherlands)

    Lindsell, J.A.; Klop, E.; Siaka, A.M.

    2011-01-01

    Human conflicts may sometimes benefit wildlife by depopulating wilderness areas but there is evidence from Africa that the impacts tend to be negative. The forested states of West Africa have experienced much recent human conflict but there have been no assessments of impacts on the wildlife. We con

  7. Air mass origins influencing TTL chemical composition over West Africa during 2006 summer monsoon

    Directory of Open Access Journals (Sweden)

    K. S. Law

    2010-11-01

    Full Text Available Trace gas and aerosol data collected in the tropical tropopause layer (TTL between 12–18.5 km by the M55 Geophysica aircraft as part of the SCOUT-AMMA campaign over West Africa during the summer monsoon in August 2006 have been analysed in terms of their air mass origins. Analysis of domain filling back trajectories arriving over West Africa, and in the specific region of the flights, showed that the M55 flights were generally representative of air masses arriving over West Africa during the first 2 weeks of August, 2006. Air originating from the mid-latitude lower stratosphere was under-sampled (in the mid-upper TTL whilst air masses uplifted from central Africa (into the lower TTL were over-sampled in the latter part of the campaign. Signatures of recent (previous 10 days origins were superimposed on the large-scale westward flow over West Africa. In the lower TTL, air masses were impacted by recent local deep convection over Africa at the level of main convective outflow (350 K, 200 hPa and on certain days up to 370 K (100 hPa. Estimates of the fraction of air masses influenced by local convection vary from 10 to 50% depending on the method applied and from day to day during the campaign. The analysis shows that flights on 7, 8 and 11 August were more influenced by local convection than on 4 and 13 August allowing separation of trace gas and aerosol measurements into "convective" and "non-convective" flights. Strong signatures, particularly in species with short lifetimes (relative to CO2 like CO, NO and fine-mode aerosols were seen during flights most influenced by convection up to 350–365 K. Observed profiles were also constantly perturbed by uplift (as high as 39% of air masses from the mid to lower troposphere over Asia, India, and oceanic regions resulting in import of clean oceanic (e.g. O3-poor or polluted air masses from Asia (high O3, CO, CO2 into West Africa. Thus, recent uplift of CO

  8. Air mass origins influencing TTL chemical composition over West Africa during 2006 summer monsoon

    Science.gov (United States)

    Law, K. S.; Fierli, F.; Cairo, F.; Schlager, H.; Borrmann, S.; Streibel, M.; Real, E.; Kunkel, D.; Schiller, C.; Ravegnani, F.; Ulanovsky, A.; D'Amato, F.; Viciani, S.; Volk, C. M.

    2010-11-01

    Trace gas and aerosol data collected in the tropical tropopause layer (TTL) between 12-18.5 km by the M55 Geophysica aircraft as part of the SCOUT-AMMA campaign over West Africa during the summer monsoon in August 2006 have been analysed in terms of their air mass origins. Analysis of domain filling back trajectories arriving over West Africa, and in the specific region of the flights, showed that the M55 flights were generally representative of air masses arriving over West Africa during the first 2 weeks of August, 2006. Air originating from the mid-latitude lower stratosphere was under-sampled (in the mid-upper TTL) whilst air masses uplifted from central Africa (into the lower TTL) were over-sampled in the latter part of the campaign. Signatures of recent (previous 10 days) origins were superimposed on the large-scale westward flow over West Africa. In the lower TTL, air masses were impacted by recent local deep convection over Africa at the level of main convective outflow (350 K, 200 hPa) and on certain days up to 370 K (100 hPa). Estimates of the fraction of air masses influenced by local convection vary from 10 to 50% depending on the method applied and from day to day during the campaign. The analysis shows that flights on 7, 8 and 11 August were more influenced by local convection than on 4 and 13 August allowing separation of trace gas and aerosol measurements into "convective" and "non-convective" flights. Strong signatures, particularly in species with short lifetimes (relative to CO2) like CO, NO and fine-mode aerosols were seen during flights most influenced by convection up to 350-365 K. Observed profiles were also constantly perturbed by uplift (as high as 39%) of air masses from the mid to lower troposphere over Asia, India, and oceanic regions resulting in import of clean oceanic (e.g. O3-poor) or polluted air masses from Asia (high O3, CO, CO2) into West Africa. Thus, recent uplift of CO2 over Asia may contribute to the observed positive CO2

  9. Air mass origins influencing TTL chemical composition over West Africa during 2006 summer monsoon

    Directory of Open Access Journals (Sweden)

    K. S. Law

    2010-06-01

    Full Text Available Trace gas and aerosol data collected in the tropical tropopause layer (TTL between 12–18.5 km by the M55 Geophysica aircraft as part of the SCOUT-AMMA campaign over West Africa during the summer monsoon in August 2006 have been analysed in terms of their air mass origins. Analysis of domain filling back trajectories arriving over West Africa, and in the specific region of the flights, showed that the M55 flights were generally representative of air masses arriving over West Africa during the first 2 weeks of August, 2006. Air originating from the mid-latitude lower stratosphere was under-sampled (in the mid-upper TTL whilst air masses uplifted from central Africa (into the lower TTL were over-sampled in the latter part of the campaign. Signatures of recent (previous 10 days origins were superimposed on the large-scale westerly flow over West Africa. In the lower TTL, air masses were impacted by recent local deep convection over Africa at the level of main convective outflow (350 K, 200 hPa and on certain days up to 370 K (100 hPa. Estimates of the fraction of air masses influenced by local convection vary from 10 to 50% depending on the method applied and from day to day during the campaign. The analysis shows that flights on 7, 8 and 11 August were more influenced by local convection than on 4 and 13 August allowing separation of trace gas and aerosol measurements into ''convective'' and ''non-convective'' flights. Strong signatures, particularly in short-lived species like CO, NO and fine-mode aerosols were seen during flights most influenced by convection up to 350–365 K. Observed profiles were also constantly perturbed by uplift (as high as 39% of air masses from the mid to lower troposphere over Asia, India, and oceanic regions resulting in import of clean oceanic (e.g., O3-poor or polluted air masses from Asia (high O3, CO, CO2 into West Africa. Thus, recent uplift of CO2 over Asia may

  10. Impact of climate change on drylands with a focus on West Africa

    Energy Technology Data Exchange (ETDEWEB)

    Dietz, A.J.; Verhagen, A.; Ruben, R. (eds.) [Impact of Climate Change on Drylands ICCD, Wageningen (Netherlands)

    2001-07-01

    The research effort started with a geographical inventory of all tropical and sub-tropical drylands to map the diversity in aridity, land degradation, population densities and urbanisation of the world's drylands, and to put the drylands of West Africa in perspective. It also guided a choice of in-depth study regions within West Africa. The scenario analysis shows a wide variety of outcomes, but with rather strong suggestions that most of dryland West Africa is expected to become a lot dryer. The consequences of these projections are an increase in high-risk environments for agriculture, including a southward shift of the and and semi-arid zones. Changes in rainfall distribution could mean an additional stress on agricultural production in these areas. Simulation studies clearly reveal a shift of the onset of the growing season and lower yield levels. To understand farmers' behaviour in West African drylands in preparing (Insuring) for dryer conditions and for agro-climatological droughts, in coping with droughts and adverse production conditions, and in adapting to changed conditions afterwards, we looked at their performance before, during and after drought years in the past identifying several adaptation strategies and policy recommendations. The conclusions are not very grim, contrary to the much-painted 'picture of doom' for Africa. West Africa's shock experience in the 1970s and 1980s did have the result that it became much better prepared for possible new drought shocks, and that its agricultural production performance in the 1990s (when rainfall became considerably better) improved. The future for the Sahel is not necessarily gloomy. However, system breakdown can occur during droughts. One may fear that in those situations religion will be used as a major catalyst for political support to exclusive claims (Islam versus Christianity and religious sub-groups versus sub-groups) and may result in massive violence and rapid deterioration

  11. Forecasted Changes in West Africa Photovoltaic Energy Output by 2045

    Directory of Open Access Journals (Sweden)

    Serge Dimitri Yikwe Buri Bazyomo

    2016-10-01

    Full Text Available The impacts of climate change on photovoltaic (PV output in the fifteen countries of the Economic Community of West African States (ECOWAS was analyzed in this paper. Using a set of eight climate models, the trends of solar radiation and temperature between 2006–2100 were examined. Assuming a lifetime of 40 years, the future changes of photovoltaic energy output for the tilted plane receptor compared to 2006–2015 were computed for the whole region. The results show that the trends of solar irradiation are negative except for the Irish Centre for High-End Computing model which predicts a positive trend with a maximum value of 0.17 W/m2/year for Cape Verde and the minimum of −0.06 W/m2/year for Liberia. The minimum of the negative trend is −0.18 W/m2/year predicted by the Model for Interdisciplinary Research on Climate (MIROC, developed at the University of Tokyo Center for Climate System Research for Cape Verde. Furthermore, temperature trends are positive with a maximum of 0.08 K/year predicted by MIROC for Niger and minimum of 0.03 K/year predicted by Nature Conservancy of Canada (NCC, Max Planck Institute (MPI for Climate Meteorology at Hamburg, French National Meteorological Research Center (CNRM and Canadian Centre for Climate Modelling and Analysis (CCCMA for Cape Verde. Photovolataic energy output changes show increasing trends in Sierra Leone with 0.013%/year as the maximum. Climate change will lead to a decreasing trend of PV output in the rest of the countries with a minimum of 0.032%/year in Niger.

  12. Technical Education and Vocational Training in Central Africa. Feasibility Survey of the Regional Development of Rapid Vocational Training: Cameroon, Central African Republic, Chad, and Gabon.

    Science.gov (United States)

    Organization for Rehabilitation through Training, Geneva (Switzerland).

    This final report is the result of a survey requested by the United States Agency for International Development (USAID) and undertaken by the Organization for Rehabilitation through Training (ORT) of four countries (Cameroon, Chad, Central African Republic, and Gabon) and a conference on vocational training sponsored by the Economic and Customs…

  13. An update on distribution models for Rhipicephalus microplus in West Africa

    Directory of Open Access Journals (Sweden)

    Eva M. De Clercq

    2013-11-01

    Full Text Available The cattle tick, Rhipicephalus microplus, which reached the West African region approximately 8 years ago, has established viable populations in Côte d’Ivoire and Benin and spread rapidly from the assumed points of introduction. However, existing maps of its distribution range do not agree on the areas at risk, most probably due to suboptimal modelling approaches. Therefore, we undertook a re-investigation of the potential distribution range based on a high-quality dataset from West Africa that includes information on 104 farms located all over Benin. Focussing on climate suitability and applying advanced modelling, a subset of representative and uncorrelated climate variables was selected and fed into Maxent software to obtain an estimate of climate suitability for West Africa. The resulting map was validated using an independent dataset of 13 farms along the apparent distribution edge. The entire southern part of West Africa (covering southern Nigeria, Benin, Togo and Ghana features high climate suitability for R. microplus. All of Côte d’Ivoire is inside the distribution range of this tick and the southern rim of Burkina Faso is expected to be suitable for the establishment of R. microplus populations. The validation of the distribution, dated one year after the initial field visit, confirmed the predicted distribution range, although a small number of individuals of R. microplus were found north of the predicted limit. These low numbers might indicate that the climate is not suitable for the establishment of a viable tick population. An alternative explanation is the recent introduction by nomadic cattle herds passing through this location. In this region of the world, it is quite common for cattle owners to lead their livestock over distances of more than 500 km in search of food and water.

  14. An update on distribution models for Rhipicephalus microplus in West Africa.

    Science.gov (United States)

    De Clercq, Eva M; Estrada-Peña, Agustin; Adehan, S; Madder, Maxime; Vanwambeke, Sophie O

    2013-11-01

    The cattle tick, Rhipicephalus microplus, which reached the West African region approximately 8 years ago, has established viable populations in Côte d'Ivoire and Benin and spread rapidly from the assumed points of introduction. However, existing maps of its distribution range do not agree on the areas at risk, most probably due to suboptimal modelling approaches. Therefore, we undertook a re-investigation of the potential distribution range based on a high-quality dataset from West Africa that includes information on 104 farms located all over Benin. Focussing on climate suitability and applying advanced modelling, a subset of representative and uncorrelated climate variables was selected and fed into Maxent software to obtain an estimate of climate suitability for West Africa. The resulting map was validated using an independent dataset of 13 farms along the apparent distribution edge. The entire southern part of West Africa (covering southern Nigeria, Benin, Togo and Ghana) features high climate suitability for R. microplus. All of Côte d'Ivoire is inside the distribution range of this tick and the southern rim of Burkina Faso is expected to be suitable for the establishment of R. microplus populations. The validation of the distribution, dated one year after the initial field visit, confirmed the predicted distribution range, although a small number of individuals of R. microplus were found north of the predicted limit. These low numbers might indicate that the climate is not suitable for the establishment of a viable tick population. An alternative explanation is the recent introduction by nomadic cattle herds passing through this location. In this region of the world, it is quite common for cattle owners to lead their livestock over distances of more than 500 km in search of food and water.

  15. The WASCAL regional climate simulations for West Africa - how to add value to existing climate projections

    Science.gov (United States)

    Arnault, J.; Heinzeller, D.; Klein, C.; Dieng, D.; Smiatek, G.; Bliefernicht, J.; Sylla, M. B.; Kunstmann, H.

    2015-12-01

    With climate change being one of the most severe challenges to rural Africa in the 21st century, West Africa is facing an urgent need to develop effective adaptation and mitigation measures to protect its constantly growing population. WASCAL (West African Science Service Center on Climate Change and Adapted Land Use) is a large-scale research-focused program designed to enhance the resilience of human and environmental systems to climate change and increased variability. An integral part of its climate services is the provisioning of a new set of high resolution, ensemble-based regional climate change scenarios for the region of West Africa. In this contribution, we present the overall concept of the WASCAL regional climate projections and provide information on the dissemination of the data. We discuss the model performance over the validation period for two of the three regional climate models employed, the Weather Research & Forecasting Tool (WRF) and the Consortium for Small-scale Modeling Model COSMO in Climate Mode (COSMO-CLM), and give details about a novel precipitation database used to verify the models. Particular attention is paid to the representation of the dynamics of the West African Summer Monsoon and to the added value of our high resolution models over existing data sets. We further present results on the climate change signal obtained from the WRF model runs for the periods 2020-2050 and 2070-2100 and compare them to current state-of-the-art projections from the CORDEX project. As an example, the figure shows the different climate change signals obtained for the total annual rainfall with respect to the 1980-2010 mean (WRF-E: WASCAL 12km high-resolution run MPI-ESM + WRFV3.5.1, CORDEX-E: 50km medium-resolution run MPI-ESM + RCA4, CORDEX-G: 50km medium-resolution run GFDL-ESM + RCA4).

  16. Effects of vegetation feedback on future climate change over West Africa

    Science.gov (United States)

    Yu, Miao; Wang, Guiling; Pal, Jeremy S.

    2016-06-01

    This study investigates the impact of climate-vegetation interaction on future climate changes over West Africa using a regional climate model with synchronous coupling between climate and natural vegetation, the RegCM4.3.4-CLM-CN-DV. Based on the lateral boundary conditions supplied by MIROC-ESM and CESM under the greenhouse gas Representative Concentration Pathway 8.5, significant increase of vegetation density is projected over the southern part of Sahel, with an increase of leaf area index and a conversion from grass to woody plants around 7-10°N of Sahel. Regardless of whether the model treats vegetation as static or dynamic, it projects an increase of precipitation in eastern Sahel and decrease in the west. The feedback due to projected vegetation change tends to cause a wet signal, enhancing the projected increase or alleviate the decrease of precipitation in JJA in the areas of projected vegetation increase. Its impact is negligible in DJF. Vegetation feedback slightly enhances projected warming in most of West Africa during JJA, but has a significant cooling effect during DJF in regions of strong vegetation changes. Future changes of surface runoff are projected to follow the direction of precipitation changes. While dynamic vegetation feedback enhances the projected increase of soil water content in JJA, it has a drying effect in DJF. The magnitude of projected ET changes is reduced in JJA and increased in DJF due to vegetation dynamics. A high sensitivity of climate projection to dynamic vegetation feedback was found mainly in semiarid areas of West Africa, with little signal in the wet tropics.

  17. Measles outbreak in a poorly vaccinated region in Cameroon: a case series study, public health challenges and recommendations.

    Science.gov (United States)

    Njim, Tsi; Aminde, Leopold Ndemnge; Feteh, Fambombi Vitalis; Ngum, Joel Mbigha; Moustapha, Chandini Aliyou

    2015-01-01

    Measles is a highly contagious viral infection and still a leading cause of vaccine-preventable deaths in Africa; especially in unvaccinated populations. We reviewed the medical reports of the measles outbreak that occurred in Misaje, in the North west region of Cameroon from 11/03/2015 to 14/05/2015. Six measles cases were recorded during this period; three of them complicated by bacterial infections. Measles should be considered as a differential diagnosis for any febrile rash especially among poorly vaccinated populations. Primary preventive methods implemented by clinicians could help control outbreaks; especially with delays in public health intervention. Also, gaps in health policies in Cameroon should be addressed to scale up vaccination coverage in remote communities like Misaje to reduce the incidence of measles outbreaks.

  18. Forecasting droughts in West Africa: Operational practice and refined seasonal precipitation forecasts

    Science.gov (United States)

    Bliefernicht, Jan; Siegmund, Jonatan; Seidel, Jochen; Arnold, Hanna; Waongo, Moussa; Laux, Patrick; Kunstmann, Harald

    2016-04-01

    Precipitation forecasts for the upcoming rainy seasons are one of the most important sources of information for an early warning of droughts and water scarcity in West Africa. The meteorological services in West Africa perform seasonal precipitation forecasts within the framework of PRESAO (the West African climate outlook forum) since the end of the 1990s. Various sources of information and statistical techniques are used by the individual services to provide a harmonized seasonal precipitation forecasts for decision makers in West Africa. In this study, we present a detailed overview of the operational practice in West Africa including a first statistical assessment of the performance of the precipitation forecasts for drought situations for the past 18 years (1998 to 2015). In addition, a long-term hindcasts (1982 to 2009) and a semi-operational experiment for the rainy season 2013 using statistical and/or dynamical downscaling are performed to refine the precipitation forecasts from the Climate Forecast System Version 2 (CFSv2), a global ensemble prediction system. This information is post-processed to provide user-oriented precipitation indices such as the onset of the rainy season for supporting water and land use management for rain-fed agriculture. The evaluation of the individual techniques is performed focusing on water-scarce regions of the Volta basin in Burkina Faso and Ghana. The forecasts of the individual techniques are compared to state-of-the-art global observed precipitation products and a novel precipitation database based on long-term daily rain-gage measurements provided by the national meteorological services. The statistical assessment of the PRESAO forecasts indicates skillful seasonal precipitation forecasts for many locations in the Volta basin, particularly for years with water deficits. The operational experiment for the rainy season 2013 illustrates the high potential of a physically-based downscaling for this region but still shows

  19. Impact of immigration on HIV-1 molecular epidemiology in West Africa, Maghreb and Southern Europe.

    Science.gov (United States)

    Miri, Lamia; Wakrim, Lahcen; Kassar, Hassène; Hemminki, Kari; Khyatti, Meriem

    2014-01-01

    There is global concern about the relation between international migration and the course of the AIDS epidemic. Maghreb is a North African region, which lies between sub-Saharan Africa and Europe. It has been turned recently into a region of immigration, since there are more and more flows of West African migrants hoping to reach European countries. Here we provide an overview on HIV-1 molecular epidemiology particularly in West African countries, Maghreb (Morocco, Algeria, Tunisia) and southern European countries (Spain, France, and Italy). The studies conducted in several countries of the region revealed different features of HIV-1 molecular epidemiology, especially for the distribution of viral subtypes and for transmitted drug resistance profiles. Furthermore, migration from West Africa to Europe seems to be a potential source of non-B subtype mobility to Maghreb and eventually to southern Europe, where HIV-1 non-B variants significantly increased in the last 10 to 15 years. As genetic differences between subtypes might impact the drug resistance pathways, it is important to provide continuous surveillance programs for the early detection of new variants spreading in the population before they become more prevalent, and to identify resistance profiles in different infected populations, especially migrants.

  20. Assessing climate adaptation options and uncertainties for cereal systems in West Africa

    Science.gov (United States)

    Guan, K.; Sultan, B.; Biasutti, M.; Lobell, D. B.

    2015-12-01

    The already fragile agriculture production system in West Africa faces further challenges in meeting food security in the coming decades, primarily due to a fast increasing population and risks of climate change. Successful adaptation of agriculture should not only benefit in the current climate but should also reduce negative (or enhance positive) impacts for climate change. Assessment of various possible adaptation options and their uncertainties provides key information for prioritizing adaptation investments. Here, based on the several robust aspects of climate projections in this region (i.e. temperature increases and rainfall pattern shifts), we use two well-validated crop models (i.e. APSIM and SARRA-H) and an ensemble of downscaled climate forcing to assess five possible and realistic adaptation options (late sowing, intensification, thermal time increase, water harvesting and increased resilience to heat stress) in West Africa for the staple crop production of sorghum. We adopt a new assessment framework to account for both the impacts of adaptation options in current climate and their ability to reduce impacts of future climate change, and also consider changes in both mean yield and its variability. Our results reveal that most proposed "adaptation options" are not more beneficial in the future than in the current climate, i.e. not really reduce the climate change impacts. Increased temperature resilience during grain number formation period is the main adaptation that emerges. We also find that changing from the traditional to modern cultivar, and later sowing in West Sahel appear to be robust adaptations.

  1. [West Nile virus infection: serological investigation among horses in France and in Africa].

    Science.gov (United States)

    Cabre, O; Durand, J P; Prangé, A; Gomez, J; Maurizi, L; Tolou, H; Davoust, B

    2005-11-01

    This study was carried out in 2003 to detected serological evidence of West Nile virus infection in 190 Army horses kept nearby French troops stationed in Southeast France and in Africa (Chad, Côte d'Ivoire and Senegal). Both IgG and IgM antibodies were searched for using an ELISA assay. Specifiity of IgG antibodies was determined by western blot and plaque reduction seroneutraization. Finding showed that 79% of the Army horses (n=96) tested in Africa presented specific IgG antibodies. All horses that were seropositive for IgG were seronegative for IgM. None of the Army horses (n=94) tested in the Southeast France were seropositive for West Nile virus. This study indicates that West Nile virus has circulated in all three African countries but not recently. It also underscores the value of western blotting as a rapid, specific confirmation technique that could eliminate the need to use plaque reduction seroneutralization.

  2. Assessing forest products usage and local residents' perception of environmental changes in peri-urban and rural mangroves of Cameroon, Central Africa

    Directory of Open Access Journals (Sweden)

    Nfotabong-Atheull Adolphe

    2011-12-01

    Full Text Available Abstract Background Deforestation is one of the most ubiquitous forms of land degradation worldwide. Although remote sensing and aerial photographs can supply valuable information on land/use cover changes, they may not regularly be available for some tropical coasts (e.g., Cameroon estuary where cloud cover is frequent. With respect to mangroves, researchers are now employing local knowledge as an alternative means of understanding forest disturbances. This paper was primarily aimed at assessing the mangrove forest products usage, along with the local people's perceptions on environmental changes, between Littoral (Cameroon estuary and Southern (mouth of the Nyong River and Mpalla village regions of Cameroon. Methods The data from both locations were obtained through conducting household interviews and field observations. Results In the Cameroon estuary (Littoral region, 69.23% of respondents (mostly elders could distinguish two to four mangrove plants, whereas the informants (65.45% in the mouth of the Nyong River and Mpalla village (mostly young people interviewed from the Southern region are familiar with only one or two commonly found mangroves. Also, more respondents from the Cameroon estuary are depending on mangroves for fuelwood (Rhizophora spp. and housing (Rhizophora spp., Avicennia germinans (L. Stearn and Nypa fruticans (Thumb. Wurmb. purposes, in contrast to Nyong River mouth and Mpalla village. Although local people perceived wood extraction as a greater disruptive factor, there are several causes for mangrove depletion in the Cameroon estuary. Among others, over-harvesting, clear-felled corridors, sand extraction and housing were found important. Furthermore, a decline in mangrove fauna composition (in terms of fishery products was recorded in the Littoral as well as Southern regions. However, the causes of such perceived negative changes were not similar in both cases. Conclusions Findings of this study highlight the need to

  3. Discovering Karima (Euphorbiaceae, a New Crotonoid Genus from West Tropical Africa Long Hidden within Croton.

    Directory of Open Access Journals (Sweden)

    Martin Cheek

    Full Text Available Croton scarciesii (Euphorbiaceae-Crotonoideae, a rheophytic shrub from West Africa, is shown to have been misplaced in Croton for 120 years, having none of the diagnostic characters of that genus, but rather a set of characters present in no known genus of the family. Pollen analysis shows that the new genus Karima belongs to the inaperturate crotonoid group. Analysis of a concatenated molecular dataset combining trnL-F and rbcL sequences positioned Karima as sister to Neoholstia from south eastern tropical Africa in a well-supported clade comprised of genera of subtribes Grosserineae and Neoboutonieae of the inaperturate crotonoid genera. Several morphological characters support the relationship of Karima with Neoholstia, yet separation is merited by numerous characters usually associated with generic rank in Euphorbiaceae. Quantitative ecological data and a conservation assessment supplement illustrations and descriptions of the taxon.

  4. Discovering Karima (Euphorbiaceae), a New Crotonoid Genus from West Tropical Africa Long Hidden within Croton

    Science.gov (United States)

    Cheek, Martin; Challen, Gill; Lebbie, Aiah; Banks, Hannah; Barberá, Patricia; Riina, Ricarda

    2016-01-01

    Croton scarciesii (Euphorbiaceae-Crotonoideae), a rheophytic shrub from West Africa, is shown to have been misplaced in Croton for 120 years, having none of the diagnostic characters of that genus, but rather a set of characters present in no known genus of the family. Pollen analysis shows that the new genus Karima belongs to the inaperturate crotonoid group. Analysis of a concatenated molecular dataset combining trnL-F and rbcL sequences positioned Karima as sister to Neoholstia from south eastern tropical Africa in a well-supported clade comprised of genera of subtribes Grosserineae and Neoboutonieae of the inaperturate crotonoid genera. Several morphological characters support the relationship of Karima with Neoholstia, yet separation is merited by numerous characters usually associated with generic rank in Euphorbiaceae. Quantitative ecological data and a conservation assessment supplement illustrations and descriptions of the taxon. PMID:27049519

  5. Discovering Karima (Euphorbiaceae), a New Crotonoid Genus from West Tropical Africa Long Hidden within Croton.

    Science.gov (United States)

    Cheek, Martin; Challen, Gill; Lebbie, Aiah; Banks, Hannah; Barberá, Patricia; Riina, Ricarda

    2016-01-01

    Croton scarciesii (Euphorbiaceae-Crotonoideae), a rheophytic shrub from West Africa, is shown to have been misplaced in Croton for 120 years, having none of the diagnostic characters of that genus, but rather a set of characters present in no known genus of the family. Pollen analysis shows that the new genus Karima belongs to the inaperturate crotonoid group. Analysis of a concatenated molecular dataset combining trnL-F and rbcL sequences positioned Karima as sister to Neoholstia from south eastern tropical Africa in a well-supported clade comprised of genera of subtribes Grosserineae and Neoboutonieae of the inaperturate crotonoid genera. Several morphological characters support the relationship of Karima with Neoholstia, yet separation is merited by numerous characters usually associated with generic rank in Euphorbiaceae. Quantitative ecological data and a conservation assessment supplement illustrations and descriptions of the taxon.

  6. Ebola virus disease control in West Africa: an ecological, one health approach.

    Science.gov (United States)

    Meseko, Clement Adebajo; Egbetade, Adeniyi Olugbenga; Fagbo, Shamsudeen

    2015-01-01

    The 2013-2015 Ebola Virus Disease outbreak in West Africa had similar nuances with the 1976 outbreaks in Central Africa; both were caused by the Zaire Ebola Virus strain and originated from rural forested communities. The definitive reservoir host of Ebola virus still remains unknown till date. However, from ecological perspective, it is known that the virus first emerged from forest ecotypes interfacing with human activities. As at March 2015, the outbreak has claimed over 9000 lives, which is unprecedented. Though it remains unproved, the primary sources of infection for past and present outbreaks are forest dwelling, human-hunted fauna. Understanding the ecological factors at play in these forest ecotypes where wild fauna interface with human and causing pathogen spill over is important. A broad based One Health approach incorporating these ecological concepts in the control of Ebola Virus Disease can effectively ameliorate or forestall infection now and in the future.

  7. Comparison of five gridded precipitation products at climatological scales over West Africa

    Science.gov (United States)

    Akinsanola, A. A.; Ogunjobi, K. O.; Ajayi, V. O.; Adefisan, E. A.; Omotosho, J. A.; Sanogo, S.

    2016-12-01

    The paper aimed at assessing the capabilities and limitations of five different precipitation products to describe rainfall over West Africa. Five gridded precipitation datasets of the Tropical Rainfall Measurement Mission (TRMM) Multi-Platform Analysis (TMPA 3B43v7); University of Delaware (UDEL version 3.01); Climatic Research Unit (CRU version 3.1); Global Precipitation Climatology Centre (GPCC version 7) and African Rainfall Climatology (ARC version 2) were compared and validated with reference ground observation data from 81 stations spanning a 19-year period, from January 1990 to December 2008. Spatial investigation of the precipitation datasets was performed, and their capability to replicate the inter-annual and intra-seasonal variability was also assessed. The ability of the products to capture the El Nino and La Nina events were also assessed. Results show that all the five datasets depicted similar spatial distribution of mean rainfall climatology, although differences exist in the total rainfall amount for each precipitation dataset. Further analysis shows that the three distinct phases of the mean annual cycle of the West Africa Monsoon precipitation were well captured by the datasets. However, CRU, GPCC and UDEL failed to capture the little dry season in the month of August while UDEL and GPCC underestimated rainfall amount in the Sahel region. Results of the inter-annual precipitation anomalies shows that ARC2 fail to capture about 46% of the observed variability while the other four datasets exhibits a greater performance (r > 0.9). All the precipitation dataset except ARC2 were consistent with the ground observation in capturing the dry and wet conditions associated with El Nino and La Nina events, respectively. ARC2 tends to overestimate the El Nino event and failed to capture the La Nina event in all the years considered. In general GPCC, CRU and TRMM were found to be the most outstanding datasets and can, therefore, be used for precipitation

  8. Potential risk of regional disease spread in West Africa through cross-border cattle trade.

    Directory of Open Access Journals (Sweden)

    Anna S Dean

    Full Text Available BACKGROUND: Transboundary animal movements facilitate the spread of pathogens across large distances. Cross-border cattle trade is of economic and cultural importance in West Africa. This study explores the potential disease risk resulting from large-scale, cross-border cattle trade between Togo, Burkina Faso, Ghana, Benin, and Nigeria for the first time. METHODS AND PRINCIPAL FINDINGS: A questionnaire-based survey of livestock movements of 226 cattle traders was conducted in the 9 biggest cattle markets of northern Togo in February-March 2012. More than half of the traders (53.5% operated in at least one other country. Animal flows were stochastically simulated based on reported movements and the risk of regional disease spread assessed. More than three quarters (79.2%, range: 78.1-80.0% of cattle flowing into the market system originated from other countries. Through the cattle market system of northern Togo, non-neighbouring countries were connected via potential routes for disease spread. Even for diseases with low transmissibility and low prevalence in a given country, there was a high risk of disease introduction into other countries. CONCLUSIONS: By stochastically simulating data collected by interviewing cattle traders in northern Togo, this study identifies potential risks for regional disease spread in West Africa through cross-border cattle trade. The findings highlight that surveillance for emerging infectious diseases as well as control activities targeting endemic diseases in West Africa are likely to be ineffective if only conducted at a national level. A regional approach to disease surveillance, prevention and control is essential.

  9. AGRHYMET: A drought monitoring and capacity building center in the West Africa Region

    Directory of Open Access Journals (Sweden)

    Seydou B. Traore

    2014-06-01

    Full Text Available The AGRHYMET Regional Center, a specialized institution of the Permanent Interstates Committee for Drought Control in the Sahel (CILSS, was created in 1974 at the aftermaths of the severe droughts that affected this region in the early 1970s. The mission assigned to the Center was to train personnel, provide adequate equipment for the meteorological and hydrological stations networks, and set up regional and national multidisciplinary working groups to monitor the meteorological, hydrological, crops and pastures conditions during the rainy season. As such, it can be considered as the West Africa drought monitoring center, similarly to its younger counterparts in Eastern and Southern Africa. After 40 years of existence, AGRHYMET’s scope of activities expend now beyond the geographical boundaries of CILSS member states, to include the whole West Africa thanks to several initiatives it has been implementing on behalf of the Economic Commission of West African States (ECOWAS on food security and environmental issues, including climate change. Throughout the years, AGRHYMET developed, in collaboration with international research organizations, models and methodologies based on ground and satellite observations to monitor rainfall, food crop water requirements satisfaction and prospective yields, the progress of vegetation front and its seasonal and interannual variations. It has trained about 1200 new experts in agrometeorology, hydrology, equipment maintenance, and plant protection, and more than 6000 professionals on topics related to food security, climate change, and sustainable natural resources (land and water management. As of now, AGRHYMET staff is involved in several international initiatives on climate change, food security, and environmental monitoring that allow them keep abreast of the best available technologies and methods, and also contribute to generating knowledge on those issues.

  10. Potential impact of climate and socioeconomic changes on future agricultural land use in West Africa

    Science.gov (United States)

    Farzan Ahmed, Kazi; Wang, Guiling; You, Liangzhi; Yu, Miao

    2016-02-01

    Agriculture is a key component of anthropogenic land use and land cover changes that influence regional climate. Meanwhile, in addition to socioeconomic drivers, climate is another important factor shaping agricultural land use. In this study, we compare the contributions of climate change and socioeconomic development to potential future changes of agricultural land use in West Africa using a prototype land use projection (LandPro) algorithm. The algorithm is based on a balance between food supply and demand, and accounts for the impact of socioeconomic drivers on the demand side and the impact of climate-induced crop yield changes on the supply side. The impact of human decision-making on land use is explicitly considered through multiple "what-if" scenarios. In the application to West Africa, future crop yield changes were simulated by a process-based crop model driven with future climate projections from a regional climate model, and future changes of food demand is projected using a model for policy analysis of agricultural commodities and trade. Without agricultural intensification, the climate-induced decrease in crop yield together with future increases in food demand is found to cause a significant increase in cropland areas at the expense of forest and grassland by the mid-century. The increase in agricultural land use is primarily climate-driven in the western part of West Africa and socioeconomically driven in the eastern part. Analysis of results from multiple scenarios of crop area allocation suggests that human adaptation characterized by science-informed decision-making can potentially minimize future land use changes in many parts of the region.

  11. Climate variability and environmental stress in the Sudan-Sahel zone of West Africa

    DEFF Research Database (Denmark)

    Mertz, Ole; D'haen, Sarah Ann Lise; Maiga, Abdou;

    2012-01-01

    Environmental change in the Sudan-Sahel region of West Africa (SSWA) has been much debated since the droughts of the 1970s. In this article we assess climate variability and environmental stress in the region. Households in Senegal, Mali, Burkina Faso, Niger, and Nigeria were asked about climatic...... changes and their perceptions were compared across north–south and west–east rainfall gradients. More than 80% of all households found that rainfall had decreased, especially in the wettest areas. Increases in wind speeds and temperature were perceived by an overall 60–80% of households. Contrary...

  12. Dynamics in carbon exchange fluxes for a grazed semi-arid savanna ecosystem in West Africa

    DEFF Research Database (Denmark)

    Tagesson, Torbern; Fensholt, Rasmus; Cropley, Ford;

    2015-01-01

    The main aim of this paper is to study land-atmosphere exchange of carbon dioxide (CO2) for semi-arid savanna ecosystems of the Sahel region and its response to climatic and environmental change. A subsidiary aim is to study and quantify the seasonal dynamics in light use efficiency (ε) being a key...... variable in scaling carbon fluxes from ground observations using earth observation data. The net ecosystem exchange of carbon dioxide (NEE) 2010-2013 was measured using the eddy covariance technique at a grazed semi-arid savanna site in Senegal, West Africa. Night-time NEE was not related to temperature...

  13. Optimal control strategies for the spread of Ebola in West Africa

    CERN Document Server

    Rachah, Amira

    2016-01-01

    The spread of Ebola virus in 2014 is unprecedented. The epidemic is still affecting West Africa, exacerbated by extraordinary socioeconomic disadvantages and health system inadequacies. With the aim of understanding, predicting, and control the propagation of the virus in the populations of affected countries, it is crucial to model the dynamics of the virus and study several strategies to control it. In this paper, we present a very simple mathematical model that describes quite well the spread of Ebola. Then, we discuss several strategies for the control of the propagation of this lethal virus into populations, in order to predict the impact of vaccine programmes, treatment, and the impact of educational campaigns.

  14. From Assistance to Partnership: Morocco and Its Foreign Policy in West Africa

    Science.gov (United States)

    2015-11-01

    Policy Papers, Bretton Woods, NH: International Monetary Fund, December 18, 2014, available from www.imf.org/external/np/pp/eng/2014/121814.pdf. 14... POLICY IN WEST AFRICA Mohammed EI-Katiri U.S. ARMY WAR COLLEGE ~~~ ~O.L STRATEGIC STUDIES INSTITUTE Report Documentation Page Form ApprovedOMB No...collection of information if it does not display a currently valid OMB control number. 1. REPORT DATE NOV 2015 2. REPORT TYPE 3. DATES COVERED 00-00

  15. Uses of graminaceous plants as food by man in West Africa

    Directory of Open Access Journals (Sweden)

    M. S. Chuah

    1983-12-01

    Full Text Available The family Gramineae, with over 7 000 species is the fifth largest family in the plant kingdom, and has over the years played a very important role in providing food for man in the form of cereals among which the most important and well-known examples are rice, wheat, maize and others. The principal graminaceous plants in man’s diet in West Africa are rice (Oryza spp.; maize (Zea mays L. and a variety of species belonging to the sorghums and millets (species of Pennisetum, Digitaria and Eleusine. Plants collected in times of famine include species of  Echinochloa, Panicum, Paspalum etc.

  16. Ciguatera fish poisoning on the West Africa Coast: An emerging risk in the Canary Islands (Spain).

    Science.gov (United States)

    Boada, Luis D; Zumbado, Manuel; Luzardo, Octavio P; Almeida-González, Maira; Plakas, Steven M; Granade, Hudson R; Abraham, Ann; Jester, Edward L E; Dickey, Robert W

    2010-12-01

    Ciguatera fish poisoning (CFP) is endemic in certain tropical and subtropical regions of the world. CFP had not been described on the West Africa Coast until a 2004 outbreak in the Canary Islands. In 2008-2009, two additional outbreaks of ciguatera occurred. Individuals afflicted had consumed lesser amberjack (Seriola rivoliana) captured from nearby waters. Caribbean ciguatoxin-1 (C-CTX-1) was confirmed in fish samples by LC-MS/MS. Ciguatoxic fish in this region may pose a new health risk for the seafood consumer.

  17. Agriculture in West Africa in the Twenty-first Century: climate change and impacts scenarios, and potential for adaptation

    Directory of Open Access Journals (Sweden)

    Benjamin Sultan

    2016-08-01

    Full Text Available West Africa is known to be particularly vulnerable to climate change due to high climate variability, high reliance on rain-fed agriculture and limited economic and institutional capacity to respond to climate variability and change. In this context, better knowledge of how climate will change in West Africa and how such changes will impact crop productivity is crucial to inform policies that may counteract the adverse effects. This review paper provides a comprehensive overview of climate change impacts on agriculture in West Africa based on the recent scientific literature. West Africa is nowadays experiencing a rapid climate change, characterized by a widespread warming, a recovery of the monsoonal precipitation, and an increase in the occurrence of climate extremes. The observed climate tendencies are also projected to continue in the 21st century under moderate and high emission scenarios, although large uncertainties still affect simulations of the future West African climate, especially regarding the summer precipitation. However, despite diverging future projections of the monsoonal rainfall, which is essential for rain-fed agriculture, a robust evidence of yield loss in West Africa emerges. This yield loss is mainly driven by increased mean temperature while potential wetter or drier conditions as well as elevated CO2 concentrations can modulate this effect. Potential for adaptation is illustrated for major crops in West Africa through a selection of studies based on process-based crop models to adjust cropping systems (change in varieties, sowing dates and density, irrigation, fertilizer management to future climate. Results of the cited studies are crop and region specific and no clear conclusions can be made regarding the most effective adaptation options difficult. Further efforts are needed to improve modelling of the monsoon system and to better quantify the uncertainty in its changes under a warmer climate, the response of the

  18. Agriculture in West Africa in the Twenty-First Century: Climate Change and Impacts Scenarios, and Potential for Adaptation.

    Science.gov (United States)

    Sultan, Benjamin; Gaetani, Marco

    2016-01-01

    West Africa is known to be particularly vulnerable to climate change due to high climate variability, high reliance on rain-fed agriculture, and limited economic and institutional capacity to respond to climate variability and change. In this context, better knowledge of how climate will change in West Africa and how such changes will impact crop productivity is crucial to inform policies that may counteract the adverse effects. This review paper provides a comprehensive overview of climate change impacts on agriculture in West Africa based on the recent scientific literature. West Africa is nowadays experiencing a rapid climate change, characterized by a widespread warming, a recovery of the monsoonal precipitation, and an increase in the occurrence of climate extremes. The observed climate tendencies are also projected to continue in the twenty-first century under moderate and high emission scenarios, although large uncertainties still affect simulations of the future West African climate, especially regarding the summer precipitation. However, despite diverging future projections of the monsoonal rainfall, which is essential for rain-fed agriculture, a robust evidence of yield loss in West Africa emerges. This yield loss is mainly driven by increased mean temperature while potential wetter or drier conditions as well as elevated CO2 concentrations can modulate this effect. Potential for adaptation is illustrated for major crops in West Africa through a selection of studies based on process-based crop models to adjust cropping systems (change in varieties, sowing dates and density, irrigation, fertilizer management) to future climate. Results of the cited studies are crop and region specific and no clear conclusions can be made regarding the most effective adaptation options. Further efforts are needed to improve modeling of the monsoon system and to better quantify the uncertainty in its changes under a warmer climate, in the response of the crops to such

  19. Radar altimetry backscattering signatures at Ka, Ku, C, and S bands over West Africa

    Science.gov (United States)

    Frappart, F.; Fatras, C.; Mougin, E.; Marieu, V.; Diepkilé, A. T.; Blarel, F.; Borderies, P.

    This study presents a comprehensive comparison of radar altimetry signatures at Ka-, Ku-, C-, and S-bands using SARAL, ENVISAT and Jason-2 data over the major bioclimatic zones, soil and vegetation types encountered in West-Africa, with an emphasis on the new information at Ka-band provided by the recently launched SARAL-Altika mission. Spatio-temporal variations of the radar altimetry responses were related to changes in surface roughness, land cover and soil wetness. Analysis of time series of backscattering coefficients along the West African bioclimatic gradient shows that radar echoes at nadir incidence are well correlated to soil moisture in semi-arid savannah environments. Radar altimeters are able to detect the presence of water even under a dense canopy cover at all frequencies. But only measurements at Ka-band are able to penetrate underneath the canopy of non-inundated tropical evergreen forests.

  20. First report of sylvatic DENV-2-associated dengue hemorrhagic fever in West Africa.

    Directory of Open Access Journals (Sweden)

    Leticia Franco

    2011-08-01

    Full Text Available Dengue virus (DENV circulates in human and sylvatic cycles. Sylvatic strains are both ecologically and evolutionarily distinct from endemic viruses. Although sylvatic dengue cycles occur in West African countries and Malaysia, only a few cases of mild human disease caused by sylvatic strains and one single case of dengue hemorrhagic fever in Malaysia have been reported. Here we report a case of dengue hemorrhagic fever (DHF with thrombocytopenia (13000/µl, a raised hematocrit (32% above baseline and mucosal bleeding in a 27-year-old male returning to Spain in November 2009 after visiting his home country Guinea Bissau. Sylvatic DENV-2 West African lineage was isolated from blood and sera. This is the first case of DHF associated with sylvatic DENV-2 in Africa and the second case worldwide of DHF caused by a sylvatic strain.

  1. First report of sylvatic DENV-2-associated dengue hemorrhagic fever in West Africa.

    Science.gov (United States)

    Franco, Leticia; Palacios, Gustavo; Martinez, José Antonio; Vázquez, Ana; Savji, Nazir; De Ory, Fernando; Sanchez-Seco, María Paz; Martín, Dolores; Lipkin, W Ian; Tenorio, Antonio

    2011-08-01

    Dengue virus (DENV) circulates in human and sylvatic cycles. Sylvatic strains are both ecologically and evolutionarily distinct from endemic viruses. Although sylvatic dengue cycles occur in West African countries and Malaysia, only a few cases of mild human disease caused by sylvatic strains and one single case of dengue hemorrhagic fever in Malaysia have been reported. Here we report a case of dengue hemorrhagic fever (DHF) with thrombocytopenia (13000/µl), a raised hematocrit (32% above baseline) and mucosal bleeding in a 27-year-old male returning to Spain in November 2009 after visiting his home country Guinea Bissau. Sylvatic DENV-2 West African lineage was isolated from blood and sera. This is the first case of DHF associated with sylvatic DENV-2 in Africa and the second case worldwide of DHF caused by a sylvatic strain.

  2. On the politics and practice of Muslim fertility: comparative evidence from West Africa.

    Science.gov (United States)

    Johnson-Hanks, Jennifer

    2006-03-01

    Recent popular works have represented Muslim fertility as dangerously high, both a cause and consequence of religious fundamentalism. This article uses comparative, statistical methods to show that this representation is empirically wrong, at least in West Africa. Although religion strongly inflects reproductive practice, its effects are not constant across different communities. In West African countries with Muslim majorities, Muslim fertility is lower than that of their non-Muslim conationals; in countries where Muslims are in the minority, their apparently higher reproductive rates converge to those of the majority when levels of education and urban residence are taken into account. A similar pattern holds for infant mortality. By contrast, in all seven countries, Muslim women are more likely to report that their most recent child was wanted. The article concludes with a discussion of the relationship between autonomy and fertility desires.

  3. Robust features of future climate change impacts on sorghum yields in West Africa

    Science.gov (United States)

    Sultan, B.; Guan, K.; Kouressy, M.; Biasutti, M.; Piani, C.; Hammer, G. L.; McLean, G.; Lobell, D. B.

    2014-10-01

    West Africa is highly vulnerable to climate hazards and better quantification and understanding of the impact of climate change on crop yields are urgently needed. Here we provide an assessment of near-term climate change impacts on sorghum yields in West Africa and account for uncertainties both in future climate scenarios and in crop models. Towards this goal, we use simulations of nine bias-corrected CMIP5 climate models and two crop models (SARRA-H and APSIM) to evaluate the robustness of projected crop yield impacts in this area. In broad agreement with the full CMIP5 ensemble, our subset of bias-corrected climate models projects a mean warming of +2.8 °C in the decades of 2031-2060 compared to a baseline of 1961-1990 and a robust change in rainfall in West Africa with less rain in the Western part of the Sahel (Senegal, South-West Mali) and more rain in Central Sahel (Burkina Faso, South-West Niger). Projected rainfall deficits are concentrated in early monsoon season in the Western part of the Sahel while positive rainfall changes are found in late monsoon season all over the Sahel, suggesting a shift in the seasonality of the monsoon. In response to such climate change, but without accounting for direct crop responses to CO2, mean crop yield decreases by about 16-20% and year-to-year variability increases in the Western part of the Sahel, while the eastern domain sees much milder impacts. Such differences in climate and impacts projections between the Western and Eastern parts of the Sahel are highly consistent across the climate and crop models used in this study. We investigate the robustness of impacts for different choices of cultivars, nutrient treatments, and crop responses to CO2. Adverse impacts on mean yield and yield variability are lowest for modern cultivars, as their short and nearly fixed growth cycle appears to be more resilient to the seasonality shift of the monsoon, thus suggesting shorter season varieties could be considered a potential

  4. Distance, Borders, and Time: The Diffusion and Permeability of Political Violence in North and West Africa

    CERN Document Server

    Skillicorn, David; Zheng, Quan; Leuprecht, Christian

    2016-01-01

    This paper explores the spatial and temporal diffusion of political violence in North and West Africa. It does so by endeavoring to represent the mental landscape that lives in the back of a group leader's mind as he contemplates strategic targeting. We assume that this representation is a combination of the physical geography of the target environment, and the mental and physical cost of following a seemingly random pattern of attacks. Focusing on the distance and time between attacks and taking into consideration the transaction costs that state boundaries impose, we wish to understand what constrains a group leader to attack at a location other than the one that would seem to yield the greatest overt payoff. By its very nature, the research problem defies the collection of a full set of structural data. Instead, we leverage functional data from the Armed Conflict Location and Event Data project (ACLED) dataset that, inter alia, meticulously catalogues violent extremist incidents in North and West Africa si...

  5. Epidemiology and vectors of Dracunculus medinensis in northwest Burkina Faso, West Africa.

    Science.gov (United States)

    Steib, K; Mayer, P

    1988-04-01

    The epidemiology of the guinea worm, Dracunculus medinensis, was studied in the dry savanna zone of West Africa. The monthly incidence data collected over a period of four years showed peak transmission occurring in June and July at the beginning of the rainy season. The different types of local water sources (i.e. wells, periodic streams, seasonal cattle waterings, natural ponds and man-made ponds) were examined for infected cyclopoid copepods. Small hand-dug ponds or water-holes situated in the fields proved to be the most important sites of transmission. While the domestic water supply is obtained from draw-wells in the villages throughout the year, the villagers take additional drinking water from these ponds during the planting season when farm activities require long stays in the fields. Four cyclopoid species were found for the first time acting as natural intermediate hosts of D. medinensis. Thermocyclops inopinus was the most frequently infected cyclopoid, and small man-made ponds are the preferred habitats of this species. Occurrence of T. inopinus is confined to the first half of the rainy season, coinciding with peak transmission. The epidemiology of dracunculiasis in dry and humid regions of West Africa is compared with regard to seasonality. The use of protective water filters proved to be the only adequate method for guinea worm control in the project area.

  6. Genetic and linguistic affinities between human populations in Eurasia and West Africa.

    Science.gov (United States)

    Nettle, Daniel; Harriss, Louise

    2003-06-01

    This study examines the relationship between genetic distance and linguistic affiliation for five regional sets of populations from Eurasia and West Africa. Human genetic and linguistic diversity have been proposed to be generally correlated, either through a direct link, whereby linguistic and genetic affiliations reflect the same past population processes, or an indirect one, where the evolution of the two types of diversity is independent but conditioned by the same geographical factors. By controlling for proximity, indirect correlations due to common geography are eliminated, and any residual relationships found are likely to reflect common linguistic-genetic processes. Clear relationships between genetic distances and linguistic relatedness are detectable in Europe and East and Central Asia, but not in the Middle East, Southeast Asia, or West Africa. We suggest that linguistic and genetic affiliations will only be correlated under specific conditions, such as where there have been large-scale demic diffusions in the last few thousand years, and relative sedentism in the subsequent period.

  7. Summer Synoptic-Scale Waves over Tropical West Africa Observed by TRMM

    Science.gov (United States)

    Starr, David O. (Technical Monitor); Gu, Guojun; Adler, Robert F.; Huffman, George J.; Curtis, Scott

    2003-01-01

    A 5-year daily rainfall dataset (3B42) from TRMM (Tropical Rainfall Measuring Mission) is used to investigate the activity and properties of westward-propagating synoptic-scale waves over tropical West Africa. Evident wave signals appearing in wavenumber-frequency space show their modulations on the surface rainfall pattern during the boreal summer. Interannual variability exists in both their intensity and spectral properties, i. e., dominant frequency and wavenumber ranges. These variabilities can be partly ascribed to year-to-year variations of their embedded large-scale environment, especially the status of mid-tropospheric African easterly jet (AEJ). Generally, a stronger (weaker) AEJ indicates more (less) instability energy yielding a stronger (weaker) wave activity season. Seasonal mean rainfall has shown an impact on these waves in some years. However, the impact is not as clear and consistent as AEJ, implying the complexity of their relationship with large-scale environment. To fully understand interannual variability of synoptic-scale waves over tropical West Africa, including the variability in their preferred frequencies and wavenumbers, it is therefore necessary to examine possible intra-seasonal variations existing in both wave activity and large-scale fields, in addition to their structure, propagation, and associated convection.

  8. THE SPECTRUM OF STUDENT ENROLLMENT-RELATED OUTCOMES IN PHYSIOTHERAPY EDUCATION PROGRAMS IN WEST AFRICA

    Directory of Open Access Journals (Sweden)

    Joseph A. Balogun

    2016-12-01

    Full Text Available Background: This cross-sectional study investigated student enrollment-related outcomes from physiotherapy education programs in West Africa. Methods: The Head of Department of all physiotherapy education programs in Nigeria and Ghana universities (N=14 completed a questionnaire that sought information on admission capacity/goal, student enrollment, baccalaureate (BPT/BS and postgraduate (MS, Ph.D. degrees conferred and the student-core faculty ratio (SFR. Results: In Nigeria, 4,748 BPT, 325 MS and 50 Ph.D. degrees in physiotherapy were conferred over a 50 year period; 2,038 BPT, 160 MS, and 42 Ph.D. students are currently enrolled. In Ghana, over a 14 year period, 277 BS degrees were conferred and 162 students are currently enrolled. The mean SFR for the undergraduate program in Nigeria and Ghana was 17.6 and 13.5, respectively. In Nigeria, 83.3% of the physiotherapy programs are located in Federal owned university; while in Ghana 100% of the programs are in State-owned university (χ² = 8.556; p =.014. Admission goal and university ownership are significantly (p<.05 influenced by the number of students annually admitted, students enrolled and SFR. Conclusion: The number of physiotherapists currently produced by universities in West Africa is inadequate to meet the regional physiotherapist needs

  9. A study of the impact of mesoscale convective systems on GPS measurements in West Africa

    Science.gov (United States)

    Nahmani, S.; Bock, O.

    2012-12-01

    Six permanent GPS stations have been deployed in West Africa within the framework of the African Monsoon Multidisciplinary Analysis (AMMA) project in order to monitor precipitable water vapor (PWV) estimates. This quantity turns out to be relevant for computing water budgets to study atmospheric processes associated with the monsoon precipitations. 90% of annual rainfalls in Sahel are produced by Mesoscale Convective Systems (MCSs). During these extreme meteorological conditions, the residuals of GPS phase measurements show strong variations that are spatially and temporally correlated. To understand the behavior of these GPS measurements, we investigated the case of MCS over Niamey (Niger) on August 11, 2006. This is a strong weather event which has already been studied by several authors but without using GPS estimates. We analyzed this event using GPS PWV estimates and phase residuals, and in-situ observations of pressure, temperature and humidity, brightness temperatures from Meteosat and measurements of reflectivity from MIT C-band Doppler radar. The residuals of GPS phase measurements, which give insight into anomalies in the refractivity of the air, revealed clearly the passage of the MCS. We analyzed also the GPS measurements from other stations for the same event which reveal the displacement of the MCS over several thousands of kilometers. The study was completed with a systematic analysis of GPS phase residuals during the whole rainy season of 2006 over West Africa.

  10. Insecticide resistance in malaria vector mosquitoes at four localities in Ghana, West Africa

    Directory of Open Access Journals (Sweden)

    Kaiser Maria L

    2011-06-01

    Full Text Available Abstract Background Malaria vector control programmes that rely on insecticide-based interventions such as indoor house spraying with residual insecticides or insecticide treated bed nets, need to base their decision-making process on sound baseline data. More and more commercial entities in Africa, such as mining companies, are realising the value to staff productivity of controlling malaria transmission in their areas of operation. This paper presents baseline entomological data obtained during surveys conducted for four mining operations in Ghana, West Africa. Results The vast majority of the samples were identified as Anopheles gambiae S form with only a few M form specimens being identified from Tarkwa. Plasmodium falciparum infection rates ranged from 4.5 to 8.6% in An. gambiae and 1.81 to 8.06% in An. funestus. High survival rates on standard WHO bioassay tests were recorded for all insecticide classes except the organophosphates that showed reasonable mortality at all locations (i.e. > 90%. The West African kdr mutation was detected and showed high frequencies in all populations. Conclusions The data highlight the complexity of the situation prevailing in southern Ghana and the challenges facing the malaria vector control programmes in this region. Vector control programmes in Ghana need to carefully consider the resistance profiles of the local mosquito populations in order to base their resistance management strategies on sound scientific data.

  11. Climate change impacts on river discharge in West Africa: a review

    Directory of Open Access Journals (Sweden)

    P. Roudier

    2014-02-01

    Full Text Available This review summarizes the impacts of climate change on runoff in West Africa, assesses the uncertainty in the projections and describes future research needs for the region. To do so, we constitute a meta-database made of 19 studies and 301 future runoff change values. The future tendency in streamflow developments is overall very uncertain (median of the 301 points is 0% and mean +5.2%, except for (i the Gambia River which exhibits a significant negative change (median = −4.5% and (ii the Sassandra and the Niger Rivers where the change is much more positive (+14.4 and +6.1%. A correlation analysis revealed that runoff changes are tightly linked to changes in rainfall (R = 0.49, and to a smaller extent also to changes in PET. Other parameters than climate such as the carbon effect on plant water efficiency, land use dynamics or water withdrawals could also significantly impact on runoff, but they generally do not offset the effects of climate change. In view of the potential changes, the large uncertainty therein, and the high vulnerability of the region to such changes, there is an urgent need for integrated studies that quantify the potential effects of these processes on water resources in West Africa. We especially underline the lack of information concerning projections of future floods and droughts, and of inter-annual fluctuations in streamflows.

  12. Viral bioterrorism: Learning the lesson of Ebola virus in West Africa 2013-2015.

    Science.gov (United States)

    Cenciarelli, Orlando; Gabbarini, Valentina; Pietropaoli, Stefano; Malizia, Andrea; Tamburrini, Annalaura; Ludovici, Gian Marco; Carestia, Mariachiara; Di Giovanni, Daniele; Sassolini, Alessandro; Palombi, Leonardo; Bellecci, Carlo; Gaudio, Pasquale

    2015-12-02

    Among the potential biological agents suitable as a weapon, Ebola virus represents a major concern. Classified by the CDC as a category A biological agent, Ebola virus causes severe hemorrhagic fever, characterized by high case-fatality rate; to date, no vaccine or approved therapy is available. The EVD epidemic, which broke out in West Africa since the late 2013, has got the issue of the possible use of Ebola virus as biological warfare agent (BWA) to come to the fore once again. In fact, due to its high case-fatality rate, population currently associates this pathogen to a real and tangible threat. Therefore, its use as biological agent by terrorist groups with offensive purpose could have serious repercussions from a psychosocial point of view as well as on closely sanitary level. In this paper, after an initial study of the main characteristics of Ebola virus, its potential as a BWA was evaluated. Furthermore, given the spread of the epidemic in West Africa in 2014 and 2015, the potential dissemination of the virus from an urban setting was evaluated. Finally, it was considered the actual possibility to use this agent as BWA in different scenarios, and the potential effects on one or more nation's stability.

  13. The Cuban Response to the Ebola Epidemic in West Africa: Lessons in Solidarity.

    Science.gov (United States)

    Chaple, Enrique Beldarraín; Mercer, Mary Anne

    2017-01-01

    In December 2013 the first case of Ebola appeared in Guinea. In September 2014 the United Nations (UN) and its specialized agency the World Health Organization (WHO) issued a call for medical collaboration in response to the medical crisis and social disaster caused by the Ebola virus epidemic in West Africa. Cuban authorities responded immediately to the call by offering specialized help for the epidemic, in collaboration with WHO. A group of 256 Cuban doctors, nurses and other health professionals provided direct care during the Ebola epidemic in Sierra Leone, Liberia and Equatorial Guinea from October 2014 to April 2015. This paper explains the main features of the Cuban health system, describes the development of Cuba's international medical cooperation approach, and highlights the work done by Cuban health collaborators in addressing the damage caused by the Ebola epidemic. Information used includes reports and documents of the Ministry of Public Health of Cuba, reports of WHO and PAHO, and articles published in scientific journals and newspaper articles. The response of the Cuban medical teams to the Ebola epidemic in West Africa is only one example of the Cuban efforts to strengthening health care provision in areas of need throughout the world.

  14. The 1 Ma Lake Bosumtwi (West Africa) Paleoclimate Record: Comparisons to Marine and Polar Records

    Science.gov (United States)

    Peck, J. A.; Shanahan, T. M.; King, J. W.; Overpeck, J. T.; Scholz, C. A.; Heil, C.; Forman, S. L.; Amoako, P. Y.

    2007-12-01

    Lake Bosumtwi is a hydrologically closed lake occupying a 1.07 Ma impact crater in Ghana, West Africa. The lake lies beneath the path of the seasonal migration of the ITCZ and therefore can provide a sedimentary record of monsoon variability in West Africa. Scientific drilling recovered a 291-m long sediment section that spans the full 1 Ma history of the lake. This long continental record is ideal for comparison to long marine and ice-core records at both glacial-interglacial and abrupt-change timescales. Oxygen-isotope stratigraphy, derived from calcareous fossils, often provides age control and a way to place individual marine sediment cores into a global stratigraphic framework. Lacking a direct tie-in to the marine oxygen-isotope stratigraphy, individual lacustrine basins can present challenges for global correlation. Through radiocarbon, optically stimulated luminescence and paleomagnetic dating, limited age control has been established for the 1 Ma Lake Bosumtwi sediment sequence. Within a Bosumtwi sediment sequence that is mostly laminated occur intervals of non-laminated sediment having increased density, decreased organic content and a high-coercivity magnetic mineral assemblage. Some of these massive layers contain slump-folding and intraformational clasts. These lithologies are interpreted to represent lake-level lowstands when a diminished West African summer monsoon resulted in decreased moisture balance and lake-level regression. Some Bosumtwi lake-level lowstands match intervals of increased sea surface salinity in the Gulf of Guinea resulting from reduced river discharge (Weldeab et al. 2007, Science, 316, 1303-1307). However, during other intervals (MIS2) there are differences between the two records. Corresponding to glacial stages and stadials, increased amounts of high-coercivity magnetic minerals are present in the Lake Bosumtwi sediment. Elevated aerosol dust export from arid Sahel sources, possibly accompanied by enhanced magnetic

  15. Male Circumcision and the Epidemic Emergence of HIV-2 in West Africa

    Science.gov (United States)

    Hewlett, Barry Stephen; Camacho, Ricardo Jorge

    2016-01-01

    Background Epidemic HIV-2 (groups A and B) emerged in humans circa 1930–40. Its closest ancestors are SIVsmm infecting sooty mangabeys from southwestern Côte d'Ivoire. The earliest large-scale serological surveys of HIV-2 in West Africa (1985–91) show a patchy spread. Côte d'Ivoire and Guinea-Bissau had the highest prevalence rates by then, and phylogeographical analysis suggests they were the earliest epicenters. Wars and parenteral transmission have been hypothesized to have promoted HIV-2 spread. Male circumcision (MC) is known to correlate negatively with HIV-1 prevalence in Africa, but studies examining this issue for HIV-2 are lacking. Methods We reviewed published HIV-2 serosurveys for 30 cities of all West African countries and obtained credible estimates of real prevalence through Bayesian estimation. We estimated past MC rates of 218 West African ethnic groups, based on ethnographic literature and fieldwork. We collected demographic tables specifying the ethnic partition in cities. Uncertainty was incorporated by defining plausible ranges of parameters (e.g. timing of introduction, proportion circumcised). We generated 1,000 sets of past MC rates per city using Latin Hypercube Sampling with different parameter combinations, and explored the correlation between HIV-2 prevalence and estimated MC rate (both logit-transformed) in the 1,000 replicates. Results and Conclusions Our survey reveals that, in the early 20th century, MC was far less common and geographically more variable than nowadays. HIV-2 prevalence in 1985–91 and MC rates in 1950 were negatively correlated (Spearman rho = -0.546, IQR: -0.553–-0.546, p≤0.0021). Guinea-Bissau and Côte d'Ivoire cities had markedly lower MC rates. In addition, MC was uncommon in rural southwestern Côte d'Ivoire in 1930.The differential HIV-2 spread in West Africa correlates with different historical MC rates. We suggest HIV-2 only formed early substantial foci in cities with substantial uncircumcised

  16. Survey of the livestock ticks of the North West province, South Africa

    Directory of Open Access Journals (Sweden)

    Arthur M. Spickett

    2011-02-01

    Full Text Available Ticks, as vectors of disease and damage agents, impact directly and indirectly on the economy of the livestock industry in southern Africa. This study surveyed the occurrence and distribution of ticks infesting livestock across the North West province, South Africa. During three phases in consecutive years, officers of the provincial Veterinary Department collected specimens monthly from livestock hosts at specified sites across the province. Data analysis constituted the fourth phase of the study. A total of 1090 collections from 265 sites yielded 42 566 tick specimens, comprising 22 different tick species (18 ixodids, 4 argasids. The specimens represent all of the major tick vectors of disease that occur in South Africa. The major tick-borne diseases (i.e. heartwater, both African and Asiatic bovine babesiosis and anaplasmosis were found to be prevalent mainly in the north-eastern region of the province, which also displayed the highest tick species diversity. The central region appears transitory to some of the major vectors. Although some tick species were contained within specific regions, others were widespread across the province. Associated serology data show that most herds sampled in areas endemic for babesiosis and anaplasmosis in the north-eastern region are endemically unstable and at risk to these tick-borne diseases should vector control measures become ineffective.

  17. Lineage 2 west nile virus as cause of fatal neurologic disease in horses, South Africa.

    Science.gov (United States)

    Venter, Marietjie; Human, Stacey; Zaayman, Dewald; Gerdes, Gertruida H; Williams, June; Steyl, Johan; Leman, Patricia A; Paweska, Janusz Tadeusz; Setzkorn, Hildegard; Rous, Gavin; Murray, Sue; Parker, Rissa; Donnellan, Cynthia; Swanepoel, Robert

    2009-06-01

    Serologic evidence suggests that West Nile virus (WNV) is widely distributed in horses in southern Africa. However, because few neurologic cases have been reported, endemic lineage 2 strains were postulated to be nonpathogenic in horses. Recent evidence suggests that highly neuroinvasive lineage 2 strains exist in humans and mice. To determine whether neurologic cases are being missed in South Africa, we tested 80 serum or brain specimens from horses with unexplained fever (n = 48) and/or neurologic signs (n = 32) for WNV. From March 2007 through June 2008, using reverse transcription-PCR (RT-PCR) and immunoglobulin (Ig) M ELISA, we found WNV RNA or IgM in 7/32 horses with acute neurologic disease; 5 horses died or were euthanized. In 5/7 horses, no other pathogen was detected. DNA sequencing for all 5 RT-PCR-positive cases showed the virus belonged to lineage 2. WNV lineage 2 may cause neurologic disease in horses in South Africa.

  18. Uncertainties in projected climate changes of the rainy season over West Africa related to bias adjustment

    Science.gov (United States)

    Nikulin, Grigory; Bosshard, Thomas; Wilcke, Renate; Yang, Wei; Kjellström, Erik; Bärring, Lars

    2015-04-01

    Bias adjustment has become an integral part of pre-processing of climate simulations for use in impact modeling studies. Considered now as a necessary step to deal with inability of climate models to accurately simulate the present/recent climate, bias adjustment is a statistical approach missing physical arguments. Even if bias adjustment is widely used nowadays it is still a topic for debates and criticism. One of the main questions is what level of uncertainty does bias adjustment introduce to future climate projections? In this study, using an ensemble of the CORDEX-Africa simulations, we investigate potential impact of bias adjustment on the simulated rainy season in West Africa. A number of characteristics reflecting different aspects of the rainy season are used, namely: onset and cessation of the rainy season, mean intensity, total amount of precipitation and intra-seasonal variability within the rainy season. All these characteristics are evaluated in the original CORDEX-Africa simulations and in bias-adjusted ones for a reference period first and then future climate projections of these characteristics are compared between two ensembles. Additionally, we examine how bias adjustment may impact selection of a smaller more manageable ensemble of regional climate simulations from a grand one.

  19. The 2014–2015 Ebola outbreak in West Africa: Hands On

    Directory of Open Access Journals (Sweden)

    Pauline Vetter

    2016-05-01

    Full Text Available Abstract The International Consortium for Prevention and Infection Control (ICPIC organises a biannual conference (ICPIC on various subjects related to infection prevention, treatment and control. During ICPIC 2015, held in Geneva in June 2015, a full one-day session focused on the 2014–2015 Ebola virus disease (EVD outbreak in West Africa. This article is a non-exhaustive compilation of these discussions. It concentrates on lessons learned and imagining a way forward for the communities most affected by the epidemic. The reader can access video recordings of all lectures delivered during this one-day session, as referenced. Topics include the timeline of the international response, linkages between the dynamics of the epidemic and infection prevention and control, the importance of community engagement, and updates on virology, diagnosis, treatment and vaccination issues. The paper also includes discussions from public health, infectious diseases, critical care and infection control experts who cared for patients with EVD in Africa, in Europe, and in the United Sates and were involved in Ebola preparedness in both high- and low-resource settings and countries. This review concludes that too little is known about the pathogenesis and treatment of EVD, therefore basic and applied research in this area are urgently required. Furthermore, it is clear that epidemic preparedness needs to improve globally, in particular through the strengthening of health systems at local and national levels. There is a strong need for culturally sensitive approaches to public health which could be designed and delivered by social scientists and medical professionals working together. As of December 2015, this epidemic killed more than 11,000 people and infected more than 28,000; it has also generated more than 17,000 survivors and orphans, many of whom face somatic and psychological complications. The continued treatment and rehabilitation of these people is a

  20. Modes, tempo and spatial variability of Cenozoic cratonic denudation: morphoclimatic constraints from West Africa

    Science.gov (United States)

    Beauvais, Anicet; Chardon, Dominique

    2010-05-01

    After the onset of Gondwana break-up in the Early Mesozoic, the emerged part of the African plate underwent long Greenhouse effect climatic periods and epeirogeny. The last Greenhouse effect period in the Early Cenozoic and the alternation of wet and dry climatic periods since the Eocene enhanced episodes of rock chemical weathering and laterite production, forming bauxites and ferricretes, interrupted by drier periods of dominantly mechanical denudation, shaping glacis [1]. In Sub-Saharan West Africa, this evolution resulted in pulsate and essentially climatically-forced denudation that has shaped an ubiquitous sequence of five stepped lateritic paleosurfaces that synchronously developed over Cenozoic times. The modes, timing and spatial variability of continental denudation of the region are investigated by combining geomorphologic and geochronological data sets. The geomorphologic data set comprises the altitudinal distribution of the lateritic paleosurfaces relicts and their differential elevation from 42 locations in Sub-Saharan West Africa where the sequence (or part of it) has been documented. The geochronological data set consists in the age ranges of each paleosurface tackled by radiometric 39Ar-40Ar dating of the neoformed oxy-hydroxides (i.e., cryptomelane, K1-2Mn8O16, nH2O, [4]) carried by their laterites at the Tambao reference site, Burkina Faso [1, 3]. Five groups of 39Ar-40Ar ages, ~ 59 - 45 Ma, ~ 29 - 24 Ma, ~ 18 - 11.5 Ma, ~ 7.2 - 5.8 Ma, and ~ 3.4 - 2.9 Ma, characterize periods of chemical weathering whereas the time laps between these groups of ages correspond to episodes of mechanical denudation that reflect physical shaping of the paleosurfaces. For the last 45 Ma, the denudation rate estimates (3 to 8 m Ma-1) are comparable with those derived on shorter time scale (103 to 106 y.) in the same region by the cosmogenic radionuclide method [2]. Combined with the geomorphologic data set, these age ranges allow the visualization of the regional

  1. Evaluating the performance of remotely sensed and reanalysed precipitation data over West Africa using HBV light

    Science.gov (United States)

    Poméon, Thomas; Jackisch, Dominik; Diekkrüger, Bernd

    2017-04-01

    Water is a crucial resource in West Africa, where large parts of the population rely on rainfed agriculture. Therefore, accurate knowledge of the water resources is of the utmost importance. Due to the declining number of rain gauging stations, the use of satellite and reanalysis precipitation datasets in hydrological modelling is steadily rising. However, accurate information on the benefits and deficits of these datasets is often lacking, especially in the West African subcontinent. For validation purposes, these products are commonly compared to freely available rain gauge data, which has in some cases already been used to bias correct the products in the first place. We therefore explored the possibility of a hydrological evaluation, where a model is calibrated for each dataset using streamflow as the observed variable. In this study, ten freely available satellite and reanalysis datasets (CFSR, CHIRPS, CMORPHv1.0 CRT, CMORPHv1.0 RAW, PERSIANN CDR, RFE 2.0, TAMSAT, TMPA 3B42v7, TMPA 3B42 RTv7 and GPCC FDDv1) were thus evaluated for six differently sized and located basins in West Africa. Results show that while performances differ, most datasets manage to somewhat accurately predict the observed streamflow in a given basin. Best results were achieved by datasets which use a multitude of input data, namely infrared and microwave satellite data, as well as observations from rain gauges (usually GPCC) for bias correction. If considering only the Nash Sutcliffe Efficiency averaged for all six basins during the calibration phase, best results were achieved by CMORPH CRT and PERSIANN CDR (both 0.66), followed by TAMSAT, CHIRPS and TMPA 3B42 (all three 0.64). Average results were achieved by RFE 2.0 (0.63), GPCC (0.61) and TMPA 3B42 RT (0.54). CMORPH RAW and CFSR performed worst (0.36 and -0.34 on average).

  2. Including Tropical Croplands in a Terrestrial Biosphere Model: Application to West Africa

    Science.gov (United States)

    Berg, A.; Sultan, B.; de Noblet, N.

    2008-12-01

    Studying the large-scale relationships between climate and agriculture raises two different issues: the impact of climate on crops, and the potential feedbacks to climate from croplands. A relevant framework to consistently address this twofold issue is to extend existing Dynamic Global Vegetation Models, which can be coupled to climate models, in order to explicitly account for croplands. Here we present the first results of such a strategy applied to tropical croplands over West Africa. We introduce directly into the terrestrial biosphere model ORCHIDEE (IPSL) adequate processes and parametrizations taken from the crop model SARRAH (CIRAD), which is calibrated for millet over this region. The resulting model, ORCH-mil, realistically simulates the growth and yield of millet when tested on an experimental station in Senegal. The model is then applied over West Africa using a 36-year climate reanalysis dataset. First the model is tested in terms of yield simulation, against national millet yields from the FAO database. The ability of the model to reproduce the spatial and temporal variability of millet yields is assessed. Then, the effects on land surface fluxes of explicitly accounting for croplands are examined, by comparison between ORCH-mil and ORCHIDEE. These first simulations show consistent results, but underline the need for some further development and validation of the model if it is to simulate yields accurately. In terms of land surface fluxes, significant differences between ORCH-mil and ORCHIDEE appear, mainly via changes in evaporation and albedo. The potential impact on the west African monsoon system of such differences needs to be investigated by coupling ORCH-mil to a climate model: first results from such an experiment will be presented.

  3. Disagreements in low-level moisture between (re)analyses over summertime West Africa

    Science.gov (United States)

    Roberts, Alexander; Marsham, John; Knippertz, Peter

    2016-04-01

    Reanalysis and operational analysis products are routinely used as the best estimates of the atmospheric state for operational and research purposes. However, different models, assimilation techniques, and assimilated datasets lead to differences between products. Here, such differences in the distribution of low-level water vapor over summertime West Africa are analyzed, as reflected in the zonal mean position of the leading edge of the West African monsoon. Five reanalysis products (NCEP-NCAR, NCEP-DOE, MERRA, CFSR and ECMWF ERA-Interim) and two operational analyses (GFS and ECMWF) are studied over 11 monsoon seasons (2000 to 2010). Specific humidity differences regularly reach 50% of the mean value over areas spanning hundreds of kilometers and often coincide with northward excursions of the ITD. These events can last several days and bring unusual rainfall to the Sahel and Sahara. The retreat phase of the monsoon excursions coincides with the peak disagreement between the ensemble of (re)analysis products and are connected with anomalously high values of aerosol optical depth (AOD). The rainfall patterns and presence of high AOD anomalies are consistent with the production of haboob dust storms. This suggests that known errors in the representation of moist convection and cold pools may contribute to the identified disagreements. Disagreement between products was lowest in 2006. During this monsoon season upper-air observations were enhanced as part of the African Monsoon Multidisciplinary Analysis (AMMA) campaign. This points to insufficient observational constraint of the (re)analyses that was greatly improved in 2006. It is hoped that this work will raise awareness of the limited reliability of (re)analysis products over West Africa during the summer, particularly during northward surges of the ITD, and will instigate further work to improve their quality.

  4. Energy services for the poor in West Africa. Sub-regional 'Energy access' study of West Africa

    Energy Technology Data Exchange (ETDEWEB)

    Sokona, Y.; Sarr, S.; Wade, S.

    2003-11-01

    The biggest challenge facing West African countries today is to reach a sustainable rate of positive economic growth that will enable them to cope with high poverty levels compounded by soaring demographic and urban growth. In a bid to stimulate a genuine dynamic of development and to rise above the economic, social, political, and environmental crises that have beset the sub-region more or less permanently since the late 1970s, the countries of the sub-region opted to subject themselves to the Structural Adjustment Programmes (SAPs) that have become the prerequisite of getting funding from multilateral co-operation donors. These SAPs were designed to be implemented in tandem with sectoral reforms. The reforms relating to the electricity sector were adopted at different periods for different countries: Cote d'Ivoire was the first to adopt them in the early 1990s, followed by Senegal, Mali, The Gambia, and, finally in 2003, Benin. In all these cases, the objectives of the reforms were clearly technical (renovation and extension of the grid, improvement of the quality of electricity) and financial or managementrelated - none of them made explicit mention of tackling poverty, not even in terms of contributing to previous poverty reduction policies. This was in spite of the fact that many countries have listed poverty reduction as one of their main national priorities by adopting Poverty Reduction Strategy Papers (PRSPs). The bulk of PRSP's do not refer specifically to energy as being one of the factors necessary for effective poverty reduction, nor do they mention electricity as a strategic factor of production. West Africa remains the sub-region with the lowest rate of electricity consumption not just in Africa but in the whole world. The annual per capita consumption varies betaveen countries from almost 350 kWh in Ghana to 27 kWh in Burkina Faso. Access to electricity in the ECOWAS region as a whole is limited to about 20% of the population. In Cote d

  5. Teachers' Perceptions of Students with Special Education Needs in Cameroon Secondary Schools

    Science.gov (United States)

    Arrah, Rosemary Oneke; Swain, Kristine D.

    2014-01-01

    This study examined teachers' perceptions of including students with special education needs in Cameroon secondary schools. Teachers (N = 130) from five secondary government, denominational or lay private schools in Buea subdivision of Cameroon, Africa, completed a 26-item survey. The survey was analyzed using descriptive statistics, t-tests, and…

  6. Vegetation dynamics and climate variability-associated biophysical process in West Africa

    Science.gov (United States)

    Song, G.; Xue, Y.; Cox, P. M.

    2012-12-01

    West Africa is a bioclimatic zone of predominantly annual grasses with shrubs and trees with a steep gradient in climate, soils, vegetation, fauna, land use and human utilization. West Africa ecosystem region suffered from the most severe and longest drought in the world during the Twentieth Century since the later 1960s. This study systematically investigates how climate variability and anomalies in West Africa affect the regional terrestrial ecosystem, including plant functional types' (PFT) spatial distribution and temporal variations and vegetation characteristics, through biophysical and photosynthesis processes at different scales. We use the offline Simplified Simple Biosphere Version 4/ Top-down Representation of Interactive Foliage and Flora Including Dynamics Model (SSiB4/TRIFFID), which is a fully coupled biophysical-dynamic vegetation (DVM) model to adequately incorporate the complex non-linear coupling dynamics between ecosystem and climate variability. The biophysical parameters in SSiB4 are adjusted with TRIFFID-produced vegetation parameter values, which ensure adequate biophysical process coupling. A 59-year simulation from 1948 was conducted using the meteorological forcing, which consists of substantial seasonal, interannual, and interdecal variability and long term dry trend. The results show that the simulated PFT's and leaf area index (LAI) correspond well to climate variability and are consistent with satellite derived vegetation conditions. The simulated inter-decadal variability in vegetation conditions is consistent with the Sahel drought in the 1970s and the 1980s and partial recovery in the 1990s and the 2000s (fig1). To further understand the biophysical mechanism of interactions of water, carbon, radiation, and vegetation dynamics, analyses are conducted to find relationships between vegetation variability and environmental conditions. It is found that the vegetation characteristics simulated by SSiB4/TRIFFID responds primarily to five

  7. Incidence of Severe Neutropenia in HIV-Infected People Starting Antiretroviral Therapy in West Africa

    Science.gov (United States)

    Leroi, Charline; Balestre, Eric; Messou, Eugene; Minga, Albert; Sawadogo, Adrien; Drabo, Joseph; Maiga, Moussa; Zannou, Marcel; Seydi, Moussa; Dabis, Francois; Jaquet, Antoine

    2017-01-01

    Background In sub-Saharan Africa, antiretroviral therapy (ART) including drugs with potential toxicity such as Zidovudine (ZDV) are routinely prescribed. This study aimed at estimating the incidence of severe neutropenia and associated factors after ART initiation in five West African countries. Methods A retrospective cohort analysis was conducted within the international epidemiologic database to evaluate AIDS (IeDEA) collaboration in West Africa. All HIV-infected adults, initiating ART between 2002 and 2014, with a baseline and at least one follow-up absolute neutrophil count (ANC) measurement were eligible. Incidence of severe neutropenia (ANC <750 cells/mm3) was estimated with 95% confidence interval (CI) according to age, gender, HIV clinic, hemoglobin, CD4 count, clinical stage, and ART duration. A Cox proportional hazard model was used to identify factors associated with severe neutropenia, expressed with their adjusted hazard ratios (aHR). Results Between 2002 and 2014, 9,426 HIV-infected adults were enrolled. The crude incidence rate of a first severe neutropenia was 9.1 per 100 person-years (95% CI: 8.6–9.8). Factors associated with severe neutropenia were exposure to ZDV <6 months (aHR = 2.2; 95% CI: 1.8–2.6), ≥6–12 months (aHR = 2.1; 95% CI: 1.6–2.8) and ≥12 months (aHR = 1.6; 95% CI: 1.2–2.2) [Ref. no ZDV exposure], CD4 count <350 cells/mm3 (aHR = 1.3; 95% CI: 1.1–1.5) and advanced clinical stage at ART initiation (aHR = 1.2; 95% CI: 1.0–1.4). Conclusion The incidence of severe neutropenia after ART initiation in West Africa is high and associated with ZDV exposure and advanced HIV disease. In this context, efforts are needed to scale-up access to less toxic first-line ART drugs and to promote early ART initiation. PMID:28122041

  8. The spatial genetic differentiation of the legume pod borer, Maruca vitrata F. (Lepidoptera: Pyralidae) populations in West Africa

    Science.gov (United States)

    The legume pod borer, Maruca vitrata, is an endemic insect pest that causes significant yield loss to the cowpea crop in West Africa, and contributes to food shortages and malnutrition in native human populations. The genetic structure of Maruca vitrata was investigated among five sites from Burkin...

  9. Monitoring HIV Risk and Evaluating Interventions among Young People in Urban West Africa: Development and Validation of an Instrument

    Science.gov (United States)

    Boileau, Catherine; Rashed, Selim; Sylla, Mohamed; Zunzunegui, Maria Victoria

    2008-01-01

    We developed an instrument for HIV/AIDS behavioral surveillance applicable to youth living in urban West Africa. The instrument includes a comprehensive set of constructs borrowed from the sociocognitive theory of planned behavior as well as measures of parental and peer communication An exploratory (n = 189) and validation sample (n = 342) of…

  10. Termite and earthworm abundance and taxonomic richness under long-term conservation soil management in Saria, Burkina Faso, West Africa

    NARCIS (Netherlands)

    Zida, Z.; Ouedraogo, E.; Mando, A.; Stroosnijder, L.

    2011-01-01

    Unsustainable crop and soil management practices are major causes of soil degradation and declining soil biodiversity in West Africa. Identifying soil management practices that favor macrofauna abundance is highly desirable for long-term soil health. This study investigates the effects of long-term

  11. Organic resources and earthworms affect phosphorus availability to sorghum after phosphate rock addition in semi-arid West Africa

    NARCIS (Netherlands)

    Ouédraogo, E.; Brussaard, L.; Mando, A.; Stroosnijder, L.

    2005-01-01

    A field experiment was laid out in Burkina Faso (West Africa) on an Eutric Cambisol to investigate the interaction of organic resource quality and phosphate rock on crop yield and to assess the contribution of earthworms (Millsonia inermis Michaelsen) to P availability after phosphate rock applicati

  12. Commodities, Prices and Risk: the changing market for non-slave products in pre-abolition in West Africa

    NARCIS (Netherlands)

    Dalrymple-Smith, A.E.; Woltjer, P.J.

    2016-01-01

    Using a newly constructed dataset on the quantities and prices of African commodities over the long 18th century this paper provides new insights into the changing nature of the non-slave trade with West Africa in the era before the abolition of the British transatlantic slave trade. We find that pr

  13. Alcohol use, viral hepatitis and liver fibrosis among HIV-positive persons in West Africa: a cross-sectional study

    Directory of Open Access Journals (Sweden)

    Antoine Jaque

    2017-01-01

    Conclusions: Considering the WHO recommendations to screen for HBV infection and treat co-infected patients with tenofovir-based ART, screening of alcohol use and brief interventions to prevent alcohol abuse should be implemented in West Africa, especially in HBV/HIV co-infected patients.

  14. Critical Limit of Extractable Phosphorous in a Gleysol for Rice Production in the Senegal River Valley of West Africa

    NARCIS (Netherlands)

    Bado, B.V.; Vries, de M.E.; Haefele, S.M.; Marco, M.C.S.; Ndiaye, M.K.

    2008-01-01

    Soil-test correlation and calibration, a useful tool for fertilizer recommendations, has been little used in West Africa. Soils from a long-term fertility experiment have been used to study the relationship between rice yields and soil extractable phosphorus (P) with Bray 1 and Olsen methods. The Ca

  15. Tailoring conservation agriculture technologies to West Africa semi-arid zones: Building on traditional local practices for soil restoration

    NARCIS (Netherlands)

    Lahmar, R.; Bationo, B.A.; Lamso, N.D.; Guéro, Y.; Tittonell, P.A.

    2012-01-01

    Low inherent fertility of tropical soils and degradation, nutrient deficiency and water stress are the key factors that hamper rainfed agriculture in semi-arid West Africa. Conservation Agriculture (CA) is currently promoted in the region as a technology to reduce soil degradation, mitigate the effe

  16. Climate change, climate variability and adaptation options in smallholder cropping systems of the Sudano - Sahel region in West Africa

    NARCIS (Netherlands)

    Traore, B.

    2014-01-01

    Key words: crop production, maize, millet, sorghum, cotton, fertilizer, rainfall, temperature, APSIM, Mali,   In the Sudano-Sahelian zone of West Africa (SSWA) agricultural production remains the main source of livelihood for rural communities, providing employment to more than 60 percent of

  17. Systems development in agricultural mechanization with special reference to soil tillage and weed control. A case study for West Africa

    NARCIS (Netherlands)

    Curfs, H.P.F.

    1976-01-01

    IntroductionMechanization in West Africa has been of limited importance and influence for farming and manual labour is the dominant power input. At present only about 0.07 kW per ha is applied, while at least about 0.37 kW is desirable to obtain high yield levels.In this mechanization study a review

  18. Mapping transmission risk of Lassa fever in West Africa: the importance of quality control, sampling bias, and error weighting.

    Science.gov (United States)

    Peterson, A Townsend; Moses, Lina M; Bausch, Daniel G

    2014-01-01

    Lassa fever is a disease that has been reported from sites across West Africa; it is caused by an arenavirus that is hosted by the rodent M. natalensis. Although it is confined to West Africa, and has been documented in detail in some well-studied areas, the details of the distribution of risk of Lassa virus infection remain poorly known at the level of the broader region. In this paper, we explored the effects of certainty of diagnosis, oversampling in well-studied region, and error balance on results of mapping exercises. Each of the three factors assessed in this study had clear and consistent influences on model results, overestimating risk in southern, humid zones in West Africa, and underestimating risk in drier and more northern areas. The final, adjusted risk map indicates broad risk areas across much of West Africa. Although risk maps are increasingly easy to develop from disease occurrence data and raster data sets summarizing aspects of environments and landscapes, this process is highly sensitive to issues of data quality, sampling design, and design of analysis, with macrogeographic implications of each of these issues and the potential for misrepresenting real patterns of risk.

  19. Mapping transmission risk of Lassa fever in West Africa: the importance of quality control, sampling bias, and error weighting.

    Directory of Open Access Journals (Sweden)

    A Townsend Peterson

    Full Text Available Lassa fever is a disease that has been reported from sites across West Africa; it is caused by an arenavirus that is hosted by the rodent M. natalensis. Although it is confined to West Africa, and has been documented in detail in some well-studied areas, the details of the distribution of risk of Lassa virus infection remain poorly known at the level of the broader region. In this paper, we explored the effects of certainty of diagnosis, oversampling in well-studied region, and error balance on results of mapping exercises. Each of the three factors assessed in this study had clear and consistent influences on model results, overestimating risk in southern, humid zones in West Africa, and underestimating risk in drier and more northern areas. The final, adjusted risk map indicates broad risk areas across much of West Africa. Although risk maps are increasingly easy to develop from disease occurrence data and raster data sets summarizing aspects of environments and landscapes, this process is highly sensitive to issues of data quality, sampling design, and design of analysis, with macrogeographic implications of each of these issues and the potential for misrepresenting real patterns of risk.

  20. Use of composts to improve soil properties and crop productivity under low input agricultural system in West Africa

    NARCIS (Netherlands)

    Ouédraogo, E.; Mando, A.; Zombré, N.P.

    2000-01-01

    Lack of adequate nutrient supply and poor soil structure are the principal constraints to crop production under low input agriculture systems of West Africa. Experiments at two sites (Mediga and Yimtenga) were conducted in Burkina Faso to assess the impact of compost on improving crop production and

  1. Walking the Path: A Reflection on How I Got Started at Tuskegee International School, Ghana, West Africa

    Science.gov (United States)

    Greenberg, Bev

    2011-01-01

    The author has given meaning to global citizenship over the past four years through the work and connections she has made with students at her school in Chicago, Francis W. Parker, and a school in the village of Madina, Ghana, West Africa, Tuskegee International. She has motivated other teachers to make connections as they traveled with her to…

  2. The Cross River gorillas (Gorilla gorilla diehli) at Mawambi Hills, South-West Cameroon: habitat suitability and vulnerability to anthropogenic disturbance.

    Science.gov (United States)

    Etiendem, Denis N; Funwi-Gabga, Neba; Tagg, Nikki; Hens, Luc; Indah, Eni K

    2013-01-01

    Only about 300 individuals of the Cross River gorilla (CRG; Gorilla gorilla diehli) survive today. The subspecies is endemic to approximately 12-14 sites at the Cameroon-Nigeria border, and is critically endangered. To understand survival prospects of the CRG at Mawambi Hills, Cameroon, a maximum entropy (MaxEnt) distribution model was used to predict the distribution of gorillas. Overall, 24% of the study area was predicted to be suitable for gorillas. The most important predictors of gorilla distribution were elevation as a surrogate for accessibility (52.4%), distance to nearby villages which represents proximity to anthropogenic disturbance (22.7%), and slope steepness as a proxy for security (19.4%). Gorillas mainly occupied slopes of steep hills and avoided areas of human disturbance. To evaluate the spatial relationship between gorilla distribution and human activities, the predicted habitat suitability map was overlaid with a kernel density map of human activities. A positive correlation was found between locations of human activity and suitable habitat for gorillas (r = 0.5). This suggests that anthropogenic pressures in previously unused forest areas are increasing as a result of resource depletion at lower altitudes, consequently putting the gorillas at greater risk. Conservation management plans that seek to reduce human encroachment into habitats preferred by gorillas such as steep hills will probably contribute to gorilla survival.

  3. Sawah Rice Eco-technology and Actualization of Green Revolution in West Africa: Experience from Nigeria and Ghana

    Institute of Scientific and Technical Information of China (English)

    O. I. OLADELE; T. WAKATSUKI

    2010-01-01

    The development and dissemination of sawah rice eco-technology in Nigeria and Ghana as prerequisites for the actualization of green revolution in West Africa were described. It showed that the neglect of the eco-technology and the overemphasis of the biotechnology have rendered the ineffective transferability of the green revolution process from Asia to Africa. The sawah eco-technology increases yield up to 5 t/hm2 through bunding and the use of inlet and outlet connecting irrigation and drainage, which enhances effective water control and management, improves the efficiency of fertilizer, improves nitrogen fixation by soil microbes and algae, increases the use of wetlands, improves soil organic matter accumulation, suppresses weed growth, and enhances immune mechanism of rice through nutrient supply. The current experience has therefore established that the technology overcomes the constraints that have limited the realization of green revolution in West Africa.

  4. [The colonial state and demographic knowledge in French West Africa, 1904-1960].

    Science.gov (United States)

    Gervais, R R

    1996-01-01

    "Our lack of knowledge on the production of population estimates in France's colonial empire is in sharp contrast to the efforts of British authorities after 1940. To understand this ¿omission', we have to assess the numerous oppositions existing within the French colonial state.... After the first memoranda of 1904 and 1909, colonial census-taking activities were inexorably merged with everyday administrative tasks: taxation, justice, policing, etc. This shift clearly influenced the form and function of demographic knowledge in French West Africa (AOF).... We conclude with a mixed assessment of attempts to amass demographic knowledge and especially of the influence such knowledge actually had on decision-making." (SUMMARY IN ENG AND SPA)

  5. Cryptosporidiosis in infancy and childhood mortality in Guinea Bissau, west Africa

    DEFF Research Database (Denmark)

    Mølbak, K; Højlyng, N; Gottschau, A

    1993-01-01

    in children who had the infection in infancy, and this excess mortality persisted into the second year of life (relative mortality 2.9 (95% confidence interval 1.7 to 4.9)). The excess mortality could not be explained by malnutrition, or by socioeconomic factors, hygienic conditions, or breast feeding......OBJECTIVE: To investigate the epidemiology of and mortality from cryptosporidiosis in young children in Guinea Bissau, West Africa. DESIGN: Three year community study of an open cohort followed up weekly. SETTING: 301 randomly selected houses in a semi-urban area in the capital, Bissau. SUBJECTS......: 1315 children aged less than 4 years. MAIN OUTCOME MEASURES: Cryptosporidium infection detected by examination of stools during episode of diarrhoea and death of a child. RESULTS: Cryptosporidium spp were found in 239 (7.4%) out of 3215 episodes of diarrhoea. The parasite was most common in younger...

  6. Impact of Mesoscale Convective Systems on GPS measurements in West Africa : statistical analysis of phase residuals

    Science.gov (United States)

    Nahmani, Samuel; Bock, Olivier

    2013-04-01

    Six permanent GPS stations have been deployed in West Africa within the framework of the African Monsoon Multidisciplinary Analysis (AMMA) project in order to monitor precipitable water vapor (PWV) estimates. This quantity turns out to be relevant for computing water budgets to study atmospheric processes associated with the monsoon precipitations. 90% of annual rainfalls in Sahel are produced by Mesoscale Convective Systems (MCSs). During these extreme meteorological conditions, the residuals of GPS phase measurements show strong variations that are spatially and temporally correlated with the passages of the MCSs. Using in-situ observations of pressure, temperature and humidity, brightness temperatures from Meteosat and measurements of reflectivity from MIT C-band Doppler radar, we analysed the cases of MCS over Niamey (Niger) during the whole rainy season of 2006. We found some signals in GPS phase residuals in connection with the structure of MCS. These signals could be used to better understand and classify these extreme meteorological events.

  7. Mineralogical, crystallographic and morphological characteristics of natural kaolins from the Ivory Coast (West Africa)

    Science.gov (United States)

    Sei, J.; Morato, F.; Kra, G.; Staunton, S.; Quiquampoix, H.; Jumas, J. C.; Olivier-Fourcade, J.

    2006-10-01

    Thirteen clay samples from four deposits in the Ivory Coast (West Africa) were studied using X-ray diffraction, thermogravimetric analysis and chemical analysis. Mineralogical, crystallographic and morphological characteristics of these samples are given. Kaolinite is the principal mineral but other minerals are present in small quantities: illite, quartz, anatase and iron oxides (oxides and oxyhydroxides). The crystallographic, morphological and surface characteristics are influenced by the presence of these impurities. In particular, the presence of iron oxides was associated with reduced structural ordering and thermal stability of kaolinite and increased specific surface area. These clays could be used in the ceramics industry to make tiles and bricks, and also in agronomy as supports for chemical fertilizers or for environmental protection by immobilising potentially toxic waste products.

  8. Socioeconomic, health and management aspects of working donkeys in Moretele 1, North West Province, South Africa

    Directory of Open Access Journals (Sweden)

    D. Wells

    2001-07-01

    Full Text Available Structured interviews using a questionnaire were conducted to gather information on socioeconomic aspects, health, nutrition, breeding and management of working equids in 3 study areas of Moretele 1 near Hammanskraal, North West Province, South Africa. The questionnaire addressed questions about the role of animals with a focus on donkeys used for work in these areas. Extension and animal health officers and donkey owners participated. The analysis highlights the use of donkeys for transport of water, wood and people; that ticks, wounds and harness sores are the conditions reported most frequently by owners; and that the range for the body condition score index of 2.7-4.0 suggests that an overall adequate level of nutrition and management is maintained in the donkeys in these villages.

  9. Accuracy of individual rapid tests for serodiagnosis of gambiense sleeping sickness in West Africa.

    Directory of Open Access Journals (Sweden)

    Vincent Jamonneau

    2015-02-01

    Full Text Available Individual rapid tests for serodiagnosis (RDT of human African trypanosomiasis (HAT are particularly suited for passive screening and surveillance. However, so far, no large scale evaluation of RDTs has been performed for diagnosis of Trypanosoma brucei gambiense HAT in West Africa. The objective of this study was to assess the diagnostic accuracy of 2 commercial HAT-RDTs on stored plasma samples from West Africa.SD Bioline HAT and HAT Sero-K-Set were performed on 722 plasma samples originating from Guinea and Côte d'Ivoire, including 231 parasitologically confirmed HAT patients, 257 healthy controls, and 234 unconfirmed individuals whose blood tested antibody positive in the card agglutination test but negative by parasitological tests. Immune trypanolysis was performed as a reference test for trypanosome specific antibody presence. Sensitivities in HAT patients were respectively 99.6% for SD Bioline HAT, and 99.1% for HAT Sero-K-Set, specificities in healthy controls were respectively 87.9% and 88.3%. Considering combined positivity in both RDTs, increased the specificity significantly (p ≤ 0.0003 to 93.4%, while 98.7% sensitivity was maintained. Specificities in controls were 98.7-99.6% for the combination of one or two RDTs with trypanolysis, maintaining a sensitivity of at least 98.1%.The observed specificity of the single RDTs was relatively low. Serial application of SD Bioline HAT and HAT Sero-K-Set might offer superior specificity compared to a single RDT, maintaining high sensitivity. The combination of one or two RDTs with trypanolysis seems promising for HAT surveillance.

  10. Regional assessment of the hydropower potential of rivers in West Africa

    Science.gov (United States)

    Kling, Harald; Stanzel, Philipp; Fuchs, Martin

    2016-04-01

    The 15 countries of the Economic Community of West African States (ECOWAS) face a constant shortage of energy supply, which limits sustained economic growth. Currently there are about 50 operational hydropower plants and about 40 more are under construction or refurbishment. The potential for future hydropower development - especially for small-scale plants in rural areas - is assumed to be large, but exact data are missing. This study supports the energy initiatives of the "ECOWAS Centre for Renewable Energy and Energy Efficiency" (ECREEE) by assessing the hydropower potential of all rivers in West Africa. For more than 500,000 river reaches the hydropower potential was computed from channel slope and mean annual discharge. In large areas there is a lack of discharge observations. Therefore, an annual water balance model was used to simulate discharge. The model domain covers 5 Mio km², including e.g. the Niger, Volta, and Senegal River basins. The model was calibrated with observed data of 410 gauges, using precipitation and potential evapotranspiration data as inputs. Historic variations of observed annual discharge between 1950 and 2010 are simulated well by the model. As hydropower plants are investments with a lifetime of several decades we also assessed possible changes in future discharge due to climate change. To this end the water balance model was driven with bias-corrected climate projections of 15 Regional Climate Models for two emission scenarios of the CORDEX-Africa ensemble. The simulation results for the river network were up-scaled to sub-areas and national summaries. This information gives a regional quantification of the hydropower potential, expected climate change impacts, as well as a regional classification for general suitability (or non-suitability) of hydropower plant size - from small-scale to large projects.

  11. Reasons for hospitalization in HIV-infected children in West Africa

    Directory of Open Access Journals (Sweden)

    Fatoumata Dicko

    2014-04-01

    Full Text Available Introduction: Current knowledge on morbidity and mortality in HIV-infected children comes from data collected in specific research programmes, which may offer a different standard of care compared to routine care. We described hospitalization data within a large observational cohort of HIV-infected children in West Africa (IeDEA West Africa collaboration. Methods: We performed a six-month prospective multicentre survey from April to October 2010 in five HIV-specialized paediatric hospital wards in Ouagadougou, Accra, Cotonou, Dakar and Bamako. Baseline and follow-up data during hospitalization were recorded using a standardized clinical form, and extracted from hospitalization files and local databases. Event validation committees reviewed diagnoses within each centre. HIV-related events were defined according to the WHO definitions. Results: From April to October 2010, 155 HIV-infected children were hospitalized; median age was 3 years [1–8]. Among them, 90 (58% were confirmed for HIV infection during their stay; 138 (89% were already receiving cotrimoxazole prophylaxis and 64 children (40% had initiated antiretroviral therapy (ART. The median length of stay was 13 days (IQR: 7–23; 25 children (16% died during hospitalization and four (3% were transferred out. The leading causes of hospitalization were WHO stage 3 opportunistic infections (37%, non-AIDS-defining events (28%, cachexia and other WHO stage 4 events (25%. Conclusions: Overall, most causes of hospitalizations were HIV related but one hospitalization in three was caused by a non-AIDS-defining event, mostly in children on ART. HIV-related fatality is also high despite the scaling-up of access to ART in resource-limited settings.

  12. Relief inversion in the geomorphological evolution of sub-Saharan West Africa

    Science.gov (United States)

    Butt, C. R. M.; Bristow, A. P. J.

    2013-03-01

    The geomorphology of much of sub-Saharan West Africa is dominated by the presence of plateaux and plains with ferruginous and, locally, aluminous (bauxitic) duricrusts. The plateaux occur at different elevations and have been correlated as two or more palaeosurfaces across much of the region. The duricrusts have generally been considered to be residual, formed by conformable erosion and chemical wasting of immediately underlying bedrock. This concept has been central to interpretations as diverse as the formation and evolution of the landscape and the development of geochemical exploration models. Recent regolith landform mapping, field observations and experience from mineral exploration in southern Mali and Burkina Faso, however, demonstrate that the duricrusts are mainly ferricretes, i.e., Fe oxide-cemented sediments. These observations require a re-interpretation of the geomorphological evolution of the region during the Cenozoic. The landscape has evolved by several cycles of weathering and erosion-deposition, triggered by climatic, tectonic or other environmental changes. It is proposed that an initial bauxitic/lateritic regolith was partly eroded following uplift and/or a change to a more arid climate, and that the detritus, rather than being removed, was deposited on slopes and valleys. During a subsequent humid period of lateritic weathering, Fe oxide cementation of this detritus formed ferricrete. Dehydration and hardening of the ferricrete after further uplift or aridity increased its resistance to erosion, resulting in relief inversion, with the detritus, in turn, being deposited downslope. This too has been weathered and cemented, to form a younger ferricrete. The occurrence of ferricrete landforms in adjacent countries, noted by field observation and inferred from satellite imagery, demonstrates that relief inversion is a very widespread and important phenomenon in southern Mali, Burkina Faso and adjacent countries in semi-arid West Africa.

  13. A new inventory for two-wheel vehicle emissions in West Africa for 2002

    Science.gov (United States)

    Assamoi, Eric-Michel; Liousse, Catherine

    2010-10-01

    Rather surprisingly, urban atmospheric particulate levels in West Africa compare with measured concentrations in Europe and Asia megacities (Liousse, C., Galy-Lacaux, C., Assamoi, E.-M., Ndiaye, A., Diop, B., Cachier, H., Doumbia, T., Gueye, P., Yoboue, V., Lacaux, J.-P., Guinot, B., Guillaume, B., Rosset, R., Castera, P., Gardrat, E., Zouiten, C., Jambert, C., Diouf, A., Koita, O., Baeza, A., Annesi-Maesano, I., Didier, A., Audry, S., Konare, A., 2009. Integrated Focus on West African Cities (Cotonou, Bamako, Dakar, Ouagadougou, Abidjan, Niamey): Emissions, Air Quality and Health Impacts of Gases and Aerosols. Third International AMMA Conference on Predictability of the West African Moosoon Weather, Climate and Impacts. Ouagadougou, Burkina Faso. July 20-24). This pollution mainly derives from road traffic emissions with, in some capitals (e.g. Cotonou), the strong contribution of two-wheel vehicles. Two key questions arise: are presently available emission inventories (e.g. Junker, C., Liousse, C., 2008. A global emission inventory of carbonaceous aerosol from historic records of fossil fuel and biofuel consumption for the period 1860-1997. Atmospheric Chemistry Physics, 8, 1-13; Bond, T.C., Streets, D.G., Yarber, K.F., Nelson, S.M., Woo, J.H., Klimont, Z., 2004. A technology-based global inventory of black and organic carbon emissions from combustion. Journal of Geophysical Research, 1009, D14203, DOI:10.1029/2003JD003697) able to account for these emissions? And, if not, how can we remedy this? The aim of this paper is to develop a methodology to estimate emissions produced by two-wheel vehicles in West Africa for 2002 in a context where reliable information is hardly available. Fuel consumption ratios between two-wheel engines (in this work) and all vehicles issued from UN database ( http://data.un.org/Data.aspx?d=EDATA&f=cmID%3aMO%3btrID%3a1221) are as high as 169%, 264% and 628%, for Burkina Faso, Mali and Chad respectively, indicating that this global

  14. New evidence for hybrid zones of forest and savanna elephants in Central and West Africa.

    Science.gov (United States)

    Mondol, Samrat; Moltke, Ida; Hart, John; Keigwin, Michael; Brown, Lisa; Stephens, Matthew; Wasser, Samuel K

    2015-12-01

    The African elephant consists of forest and savanna subspecies. Both subspecies are highly endangered due to severe poaching and habitat loss, and knowledge of their population structure is vital to their conservation. Previous studies have demonstrated marked genetic and morphological differences between forest and savanna elephants, and despite extensive sampling, genetic evidence of hybridization between them has been restricted largely to a few hybrids in the Garamba region of northeastern Democratic Republic of Congo (DRC). Here, we present new genetic data on hybridization from previously unsampled areas of Africa. Novel statistical methods applied to these data identify 46 hybrid samples--many more than have been previously identified--only two of which are from the Garamba region. The remaining 44 are from three other geographically distinct locations: a major hybrid zone along the border of the DRC and Uganda, a second potential hybrid zone in Central African Republic and a smaller fraction of hybrids in the Pendjari-Arli complex of West Africa. Most of the hybrids show evidence of interbreeding over more than one generation, demonstrating that hybrids are fertile. Mitochondrial and Y chromosome data demonstrate that the hybridization is bidirectional, involving males and females from both subspecies. We hypothesize that the hybrid zones may have been facilitated by poaching and habitat modification. The localized geography and rarity of hybrid zones, their possible facilitation from human pressures, and the high divergence and genetic distinctness of forest and savanna elephants throughout their ranges, are consistent with calls for separate species classification.

  15. Satellite-based Assessment of Fire Impacts on Ecosystem Changes in West Africa

    Science.gov (United States)

    Ichoku, Charles

    2008-01-01

    Fires bum many vegetated regions of the world to a variety of degrees and frequency depending on season. Extensive biomass burning occurs in most parts of sub-Saharan Africa, posing great threat to ecosystem stability among other real and potential adverse impacts. In Africa, such landscape-scale fires are used for various agricultural purposes, including land clearing and hunting, although there may be a limited number of cases of fires ignited by accident or due to arson. Satellite remote sensing provides the most practical means of mapping fires, because of their sudden and aggressive nature coupled with the tremendous heat they generate. Recent advancements in satellite technology has enabled, not only the identification of fire locations, but also the measurement of fire radiative energy (FRE) release rate or power (FRP), which has been found to have a direct linear relationship with the rate of biomass combustion. A recent study based on FRP measurements from the Moderate-resolution imaging Spectro-radiometer (MODIS) sensor aboard the Terra and Aqua satellites revealed that, among all the regions of the world where fires occur, African regions rank the highest in the intensity of biomass burning per unit area of land during the peak of the burning season. In this study, we will analyze the burning patterns in West Africa during the last several years and examine the extent of their impacts on the ecosystem dynamics, using a variety of satellite data. The study introduces a unique methodology that can be used to build up the knowledge base from which decision makers can obtain scientific information in fomulating policies for regulating biomass burning in the region.

  16. Occurrence, aetiology and challenges in the management of congestive heart failure in sub-saharan Africa: experience of the Cardiac Centre in Shisong, Cameroon

    Directory of Open Access Journals (Sweden)

    Tantchou Tchoumi Jacques Cabral

    2011-02-01

    Full Text Available INTRODUCTION: The aim of the study was to investigate the occurrence, the aetiology and the management of congestive heart failure in the cardiac centre of the St. Elizabeth catholic general hospital Shisong in Cameroon. METHODS: Between November 2002 and November 2008, a population of 8121 patients was consulted in the referral cardiac centre of St. Elizabeth Catholic General Hospital. Of these patients, 462 were diagnosed with congestive heart failure according to the modified Framingham criteria for the diagnosis of heart failure. Complementary investigations used to confirm and establish the aetiology of the disease were the chest X-ray, electrocardiography, bi-dimensional Doppler echocardiography. RESULTS: The results showed that the occurrence of congestive heart failure in our centre was 5,7%. Congestive heart failure was diagnosed in 198 females and 264 males, aged between 8 and 86 years old (42.5, plus or minus 18 years old. Post rheumatic valvulopathies (14.6% and congenital heart diseases (1.9% were the first aetiologic factor of congestive heart failure in the young, meanwhile cardiomyopathies (8,3% in elderly followed by hypertensive cardiomyopathy (4.4%. Congestive heart failure was also seen in adults with congenital heart diseases in 0.01%. In this zone of Cameroon, we discovered that HIV cardiomyopathy (1.6% and Cor pulmonale (8% were represented, aetiological factors not mentioned in previous studies conducted in urban areas of Cameroon. The mean duration of hospital stay for the compensation treatment was thirteen days, ranging between 7 and 21 days, the mortality being 9.2%. All the medications recommended for the treatment of congestive heart failure are available in our centre but many patients are not compliant to the therapy or cannot afford them. Financial limitation is causing the exacerbation of the disease and premature death. CONCLUSION: Our data show a high incidence of congestive heart failure mainly due to post

  17. West Africa - a safe haven for frogs? A sub-continental assessment of the chytrid fungus (Batrachochytrium dendrobatidis.

    Directory of Open Access Journals (Sweden)

    Johannes Penner

    Full Text Available A putative driver of global amphibian decline is the panzootic chytrid fungus Batrachochytrium dendrobatidis (Bd. While Bd has been documented across continental Africa, its distribution in West Africa remains ambiguous. We tested 793 West African amphibians (one caecilian and 61 anuran species for the presence of Bd. The samples originated from seven West African countries - Bénin, Burkina Faso, Côte d'Ivoire, Ghana, Guinea, Liberia, Sierra Leone - and were collected from a variety of habitats, ranging from lowland rainforests to montane forests, montane grasslands to humid and dry lowland savannahs. The species investigated comprised various life-history strategies, but we focused particularly on aquatic and riparian species. We used diagnostic PCR to screen 656 specimen swabs and histology to analyse 137 specimen toe tips. All samples tested negative for Bd, including a widespread habitat generalist Hoplobatrachus occipitalis which is intensively traded on the West African food market and thus could be a potential dispersal agent for Bd. Continental fine-grained (30 arc seconds environmental niche models suggest that Bd should have a broad distribution across West Africa that includes most of the regions and habitats that we surveyed. The surprising apparent absence of Bd in West Africa indicates that the Dahomey Gap may have acted as a natural barrier. Herein we highlight the importance of this Bd-free region of the African continent - especially for the long-term conservation of several threatened species depending on fast flowing forest streams (Conraua alleni ("Vulnerable" and Petropedetes natator ("Near Threatened" as well as the "Critically Endangered" viviparous toad endemic to the montane grasslands of Mount Nimba (Nimbaphrynoides occidentalis.

  18. Delayed Closure of Giant Omphaloceles in West Africa: Report of Five Cases

    Science.gov (United States)

    El Ezzi, Oumama; Bossou, Raymond; Reinberg, Olivier; Maurer, Sabine Vasseur; Roessingh, Anthony de Buys

    2017-01-01

    Giant omphalocele (GO) management is controversial and not easy. Conservative management at birth and delayed surgical closure is usually mandatory. Postponed surgery may be challenging and carry the risk of intensive care treatment. We report on five children who were treated in our department for GO between 2000 and 2010. Initially, the patients were managed conservatively in West Africa. Delayed closure of the ventral hernia was performed in Switzerland after patient transfer through a nongovernmental organization. Fascial closure was performed at the median age of 23 months. Median diameter of the hernias was 10 × 10 cm ranging from 10 × 8 cm to 24 × 15 cm. Four (80%) patients had associated anomalies. Three children needed mechanical ventilation in the intensive care unit after surgery. Median hospitalization was 19 days. Complications were seen in two patients. The follow-up showed no recurrence of ventral hernia. There was no mortality. This report shows that conservative management of a GO at birth with delayed closure of the ventral hernia after transferring the patients to a European center is a safe approach for West African children and avoids life-threatening procedures. Delayed closure of a GO may be nevertheless challenging everywhere.

  19. Climate variability and environmental stress in the Sudan-Sahel zone of West Africa.

    Science.gov (United States)

    Mertz, Ole; D'haen, Sarah; Maiga, Abdou; Moussa, Ibrahim Bouzou; Barbier, Bruno; Diouf, Awa; Diallo, Drissa; Da, Evariste Dapola; Dabi, Daniel

    2012-06-01

    Environmental change in the Sudan-Sahel region of West Africa (SSWA) has been much debated since the droughts of the 1970s. In this article we assess climate variability and environmental stress in the region. Households in Senegal, Mali, Burkina Faso, Niger, and Nigeria were asked about climatic changes and their perceptions were compared across north-south and west-east rainfall gradients. More than 80% of all households found that rainfall had decreased, especially in the wettest areas. Increases in wind speeds and temperature were perceived by an overall 60-80% of households. Contrary to household perceptions, observed rainfall patterns showed an increasing trend over the past 20 years. However, August rainfall declined, and could therefore potentially explain the contrasting negative household perceptions of rainfall trends. Most households reported degradation of soils, water resources, vegetation, and fauna, but more so in the 500-900 mm zones. Adaptation measures to counter environmental degradation included use of manure, reforestation, soil and water conservation, and protection of fauna and vegetation. The results raise concerns for future environmental management in the region, especially in the 500-900 mm zones and the western part of SSWA.

  20. Probabilistic Impact Assessment of Domestic Rainwater Harvesting in Urban Slums: West Africa Case Study

    Science.gov (United States)

    Cowden, J. R.; Watkins, D. W.; Mihelcic, J. R.; Fry, L. M.

    2007-12-01

    Urban populations now exceed rural populations worldwide, creating unique challenges in providing basic services, especially in developing countries where informal or illegal settlements grow in peri-urban areas. West Africa is an acute example of the problems created by rapid urban growth, with high levels of urban poverty and low water and sanitation access rates. Although considerable effort has been made in providing improved water access and urban services to slum communities, research indicates that clean water access rates are not keeping up with urbanization rates in several areas of the world and that rapidly growing slum communities are beginning to overwhelm many prior water improvements projects. In the face of these challenges, domestic rainwater harvesting is proposed as a technologically appropriate and economically viable option for enhancing water supplies to urban slum households. However, assessing the reliability, potential health impacts, and overall cost-effectiveness of these systems on a regional level is difficult for several reasons. First, long daily rainfall records are not readily available in much of the developing world, including many regions of sub-Saharan Africa. Second, significant uncertainties exist in the relevant cost, water use, and health data. Third, to estimate the potential future impacts at the regional scale, various global change scenarios should be investigated. Finally, in addition to these technical challenges, there is also a need to develop relatively simple and transparent assessment methods for informing policy makers. A procedure is presented for assessment of domestic rainwater harvesting systems using a combination of scenario, sensitivity, and trade-off analyses. Using data from West Africa, simple stochastic weather models are developed to generate rainfall sequences for the region, which are then used to estimate the reliability of providing a range of per capita water supplies. Next, a procedure is

  1. Extensive nitrogen loss from permeable sediments off North-West Africa

    Science.gov (United States)

    Sokoll, Sarah; Lavik, Gaute; Sommer, Stefan; Goldhammer, Tobias; Kuypers, Marcel M. M.; Holtappels, Moritz

    2016-04-01

    The upwelling area off North-West Africa is characterized by high export production, high nitrate and low oxygen concentration in bottom waters. The underlying sediment consists of sands that cover most of the continental shelf. Due to their permeability sands allow for fast advective pore water transport and can exhibit high rates of nitrogen (N) loss via denitrification as reported for anthropogenically eutrophied regions. However, N loss from sands underlying naturally eutrophied waters is not well studied, and in particular, N loss from the North-West African shelf is poorly constrained. During two research cruises in April/May 2010/2011, sediment was sampled along the North-West African shelf and volumetric denitrification rates were measured in sediment layers down to 8 cm depth using slurry incubations with 15N-labeled nitrate. Areal N loss was calculated by integrating volumetric rates down to the nitrate penetration depth derived from pore water profiles. Areal N loss was neither correlated with water depth nor with bottom water concentrations of nitrate and oxygen but was strongly dependent on sediment grain size and permeability. The derived empirical relation between benthic N loss and grains size suggests that pore water advection is an important regulating parameter for benthic denitrification in sands and further allowed extrapolating rates to an area of 53,000 km2 using detailed sediment maps. Denitrification from this region amounts to 995 kt yr-1 (average 3.6 mmol m-2 d-1) which is 4 times higher than previous estimates based on diffusive pore water transport. Sandy sediments cover 50-60% of the continental shelf and thus may contribute significantly to the global benthic N loss.

  2. The nutrition and health impact of cash cropping in west Africa: a historical perspective.

    Science.gov (United States)

    Brun, T A

    1991-01-01

    The impact of cash cropping in West Africa cannot be isolated from its social and historical background. Among the many changes brought to West African economies by cash cropping since the beginning of the century, the present document shows how the extension of trade with European merchants and colonizers created new sets of values and criteria for wealth. Food crops gradually lost their prominent cultural and economics roles to the benefit of export crops or goods. Traditional systems of agricultural production were profoundly disrupted by military actions. They imposed colonial rule and control of trade of tropical crops and goods. Forced labor and compulsory (poorly paid) work assignments were instituted for private and public enterprises: construction of roads, railways, public buildings and plantations. The main justification was the need for cheap labor to cultivate, transport and build roads for the extraction of raw materials. This in turn caused massive migrations from countries such as Burkina Faso (Upper Volta) to Ivory Coast. Cash cropping made systematic collection of taxes possible. An imposition on a per capita basis became the rule and the major incentive of small farmers to engage in commercial farming. Cash cropping made also possible extensive monetarization of West Africa. This results in both favorable and unfavorable effects on the quality of the diet. In profoundly disrupted traditional societies, the diffusion of new consumption patterns was easier and faster. It led to massive food imports of wheat, rice, sugar, alcohol, etc. Cash cropping was (and still is) practiced as a 'mining' agriculture, exhausting soils and deteriorating their fertility for extended periods of time. In the Sudanian and Sahelian zones cash cropping conflicted with the cultivation of grains because peak demands for labor were similar. Therefore, millet and sorghum production declined. Cash cropping was developed in response to the need of European economies for

  3. Isoprene emissions modelling for West Africa: MEGAN model evaluation and sensitivity analysis

    Directory of Open Access Journals (Sweden)

    J. Ferreira

    2010-09-01

    Full Text Available Isoprene emissions are the largest source of reactive carbon to the atmosphere, with the tropics being a major source region. These natural emissions are expected to change with changing climate and human impact on land use. As part of the African Monsoon Multidisciplinary Analyses (AMMA project the Model of Emissions of Gases and Aerosols from Nature (MEGAN has been used to estimate the spatial and temporal distribution of isoprene emissions over the West African region. During the AMMA field campaign, carried out in July and August 2006, isoprene mixing ratios were measured on board the FAAM BAe-146 aircraft. These data have been used to make a qualitative evaluation of the model performance.

    MEGAN was firstly applied to a large area covering much of West Africa from the Gulf of Guinea in the south to the desert in the north and was able to capture the large scale spatial distribution of isoprene emissions as inferred from the observed isoprene mixing ratios. In particular the model captures the transition from the forested area in the south to the bare soils in the north, but some discrepancies have been identified over the bare soil, mainly due to the emission factors used. Sensitivity analyses were performed to assess the model response to changes in driving parameters, namely Leaf Area Index (LAI, Emission Factors (EF, temperature and solar radiation.

    A high resolution simulation was made of a limited area south of Niamey, Niger, where the higher concentrations of isoprene were observed. This is used to evaluate the model's ability to simulate smaller scale spatial features and to examine the influence of the driving parameters on an hourly basis through a case study of a flight on 17 August 2006.

    This study highlights the complex interactions between land surface processes and the meteorological dynamics and chemical composition of the PBL. This has implications for quantifying the impact of biogenic emissions

  4. An overview of the nutrition transition in West Africa: implications for non-communicable diseases.

    Science.gov (United States)

    Bosu, William K

    2015-11-01

    The nutrition landscape in West Africa has been dominated by the programmes to address undernutrition. However, with increasing urbanisation, technological developments and associated change in dietary patterns and physical activity, childhood and adult overweight, and obesity are becoming more prevalent. There is an evidence of increasing intake of dietary energy, fat, sugars and protein. There is low consumption of fruit and vegetables universally in West Africa. Overall, the foods consumed are predominantly traditional with the component major food groups within recommended levels. Most of the West African countries are at the early stages of nutrition transition but countries such as Cape Verde, Ghana and Senegal are at the latter stages. In the major cities of the region, children consume energy-dense foods such as candies, ice cream and sweetened beverages up to seven times as frequently as fruit and vegetables. Adult obesity rates have increased by 115 % in 15 years since 2004. In Ghana, the prevalence of overweight/obesity in women has increased from 12·8 % in 1993 to 29·9 % in 2008. In Accra, overweight/obesity in women has increased from 62·2 % in 2003 to 64·9 % in 2009. The age-standardised proportion of adults who engage in adequate levels of physical activity ranges from 46·8 % in Mali to 94·7 % in Benin. The lingering stunting in children and the rising overweight in adults have resulted to a dual burden of malnutrition affecting 16·2 % of mother-child pairs in Cotonou. The prevalence of hypertension has been increased and ranges from 17·6 % in Burkina Faso to 38·7 % in Cape Verde. The prevalence is higher in the cities: 40·2 % in Ougadougou, 46·0 % in St Louis and 54·6 % in Accra. The prevalence of diabetes ranges from 2·5 to 7·9 % but could be as high as 17·9 % in Dakar, Senegal. The consequences of nutrition transition are not only being felt by the persons in the high socioeconomic class, but also in cities such as Accra and

  5. South Atlantic continental margins of Africa: a comparison of the tectonic vs climate interplay on the evolution of equatorial west Africa and SW Africa margins

    CERN Document Server

    Seranne, M; Seranne, Michel; Anka, Zahie

    2005-01-01

    The comparative review of 2 representative segments of Africa continental margin: the equatorial western Africa and the SW Africa margins, helps in analysing the main controlling factors on their development. Early Cretaceous active rifting S of the Walvis Ridge resulted in the formation of the SW Africa volcanic margin. The non-volcanic rifting N of the Walvis ridge, led to the formation of the equatorial western Africa margin, with thick and extensive, synrift basins. Regressive erosion of SW Africa prominent shoulder uplift accounts for high clastic sedimentation rate in Late Cretaceous - Eocene, while dominant carbonate production on equatorial western Africa shelf suggests little erosion of a low hinterland. The early Oligocene climate change had contrasted response in both margins. Emplacement of the Congo deep-sea fan reflects increased erosion in equatorial Africa, under the influence of wet climate, whereas establishment of an arid climate over SW Africa induced a drastic decrease of denudation, and ...

  6. WJH 6th Anniversary Special Issues(2): Hepatocellular carcinoma Problem of hepatocellular carcinoma in West Africa

    Institute of Scientific and Technical Information of China (English)

    Nimzing; G; Ladep; Olufunmilayo; A; Lesi; Pantong; Mark; Maud; Lemoine; Charles; Onyekwere; Mary; Afihene; Mary; ME; Crossey; Simon; D; Taylor-Robinson

    2014-01-01

    The incidence of hepatocellular carcinoma(HCC) isknown to be high in West Africa with an approximateyearly mortality rate of 200000. Several factors are responsible for this. Early acquisition of risk factors; with vertical or horizontal transmission of hepatitis B(HBV), environmental food contaminants(aflatoxins), poor management of predisposing risk factors and poorlymanaged strategies for health delivery. There has been a low uptake of childhood immunisation for hepatitis B in many West African countries. Owing to late presentations, most sufferers of HCC die within weeks of their diagnosis. Highlighted reasons for the specific disease pattern of HCC in West Africa include:(1) high rate of risk factors;(2) failure to identify at risk populations;(3) lack of effective treatment; and(4) scarce resources for timely diagnosis. This is contrasted to the developed world, which generally has sufficient resources to detect cases early for curative treatment. Provision of palliative care for HCC patients is limited by availability and affordability of potent analgesics. Regional efforts, as well as collaborative networking activities hold promise that could change the epidemiology of HCC in West Africa.

  7. Characteristics of HIV-2 and HIV-1/HIV-2 Dually Seropositive Adults in West Africa Presenting for Care and Antiretroviral Therapy: The IeDEA-West Africa HIV-2 Cohort Study

    OpenAIRE

    Ekouevi, Didier K; Coffie, Patrick A.; Eugene Messou; Adrien Sawadogo; Eholie, Serge P.; Djimon Marcel Zannou; Carin Ahouada; Jocelyn Akakpo; Christelle Ahomadegbé; Jules Bashi; Alice Gougounon-Houéto; Angèle Azon-Kouanou; Fabien Houngbé; Sikiratou Koumakpaï; Florence Alihonou

    2013-01-01

    Background HIV-2 is endemic in West Africa. There is a lack of evidence-based guidelines on the diagnosis, management and antiretroviral therapy (ART) for HIV-2 or HIV-1/HIV-2 dual infections. Because of these issues, we designed a West African collaborative cohort for HIV-2 infection within the framework of the International epidemiological Databases to Evaluate AIDS (IeDEA). Methods We collected data on all HIV-2 and HIV-1/HIV-2 dually seropositive patients (both ARV-naive and starting ART)...

  8. The quest for safe drinking water: an example from Guinea-Bissau (West Africa).

    Science.gov (United States)

    Bordalo, Adriano A; Savva-Bordalo, Joana

    2007-07-01

    While humans require water for life, one-sixth of our species lives without access to safe water. In Africa, the situation is particularly acute because of global warming, the progression of the Sahara desert, civil unrest and poor governance, population growth, migration and poverty. In rural areas, the lack of adequate safe water and sanitary infrastructures leaves millions with doubtful water quality, increasing the harshness of daily life. In this paper, a pilot study was conducted during the wet season on Bolama Island (Guinea-Bissau, West Africa), a UNESCO Man and the Biosphere Reserve. Twenty-eight shallow wells, supplying water to most of the population, were sampled for microbiological, physical and chemical water quality characteristics. A ten-parameter water quality index (WQI) adapted to tropical conditions was applied to compare the different wells. About 79% of the wells showed moderate to heavy fecal contamination. From the surveyed parameters, it was found that chemical contamination was less important, although all samples were acidic, with the pH averaging 5.12+/-0.08. The WQI was 43+/-4% (0%-worst; 100%-best quality), showing that the water from the majority of wells was polluted but should be suitable for domestic use after appropriate treatment. At the onset of the wet season, diarrhea represented 11.5% of all medical cases, 92.5% of which were children aged <15. This paper suggests inexpensive steps to reduce the fecal contamination and control the pH in order to increase the potability of the well water and, concomitantly, to raise the living standards of the population in one of the poorest countries of the world.

  9. A disseminated case of Buruli ulcer at Macenta in the forest region of Guinea in West Africa

    Institute of Scientific and Technical Information of China (English)

    Bafende Aombe Eric; Strahm Stefan; Loua Richard.; Beavogui Galada Daniel; Kolie Valentin; Guilavogui Raphael; Keita Samba

    2012-01-01

    The author report a confirmed case of Buruli ulcer at Macenta in the forest region of Guinea in West Africa. An 8 years old girl came to the general hospital of Macenta located in the forest region of Guinea at 800km south-west of Conakry. Her story reveals that she used to swim in the local river of Man region in Ivory Coast. There is no notion of trauma or insect bite .The disease started 2 years ago by a nodule of the skin in her right leg which had ulcerated; she received various traditional treatments.

  10. Vertical structure of aerosols and water vapor over West Africa during the African monsoon dry season

    Directory of Open Access Journals (Sweden)

    S.-W. Kim

    2009-10-01

    Full Text Available We present observations of tropospheric aerosol and water vapor transport over West Africa and the associated meteorological conditions during the AMMA SOP-0 dry season experiment, which was conducted in West Africa in January–February 2006. This study combines data from ultra-light aircraft (ULA-based lidar, airborne in-situ aerosol and gas measurements, standard meteorological measurements, satellite-based aerosol measurements, airmass trajectories, and radiosonde measurements. At Niamey (13.5° N, 2.2° E the prevailing surface wind (i.e. Harmattan was from the northeast bringing dry dusty air from the Sahara desert. High concentrations of mineral dust aerosol were typically observed from the surface to 1.5 or 2 km associated with the Saharan airmasses. At higher altitudes the prevailing wind veered to the south or southeast bringing relatively warm and humid airmasses from the biomass burning regions to the Sahel (<10° N. These elevated layers had high concentrations of biomass burning aerosol and were typically observed between altitudes of 2–5 km. Meteorological analyses show these airmasses were advected upwards over the biomass burning regions through ascent in Inter-Tropical Discontinuity (ITD zone. Aerosol vertical profiles obtained from the space-based lidar CALIOP onboard CALIPSO during January 2007 also showed the presence of dust particles (particle depolarization (δ~30%, lidar Ångström exponent (LAE<0, aerosol backscatter to extinction ratio (BER: 0.026~0.028 sr−1 at low levels (<1.5 km and biomass burning smoke aerosol (δ<10%, LAE: 0.6~1.1, BER: 0.015~0.018 sr−1 between 2 and 5 km. CALIOP data indicated that these distinct continental dust and biomass burning aerosol layers likely mixed as they advected further south over the tropical Atlantic Ocean, as indicated an intermediate values of δ (10~17%, LAE (0.16~0.18 and BER (0.0021~0.0022 sr−1.

  11. Radiative impact of mineral dust on monsoon precipitation variability over West Africa

    Directory of Open Access Journals (Sweden)

    C. Zhao

    2010-11-01

    Full Text Available The radiative forcing of dust and its impact on precipitation over the West Africa monsoon (WAM region is simulated using a coupled meteorology and aerosol/chemistry model (WRF-Chem. During the monsoon season, dust is a dominant contributor to aerosol optical depth (AOD over West Africa. In the control simulation, on 24-h domain average, dust has a cooling effect (−6.11 W/m2 at the surface, a warming effect (6.94 W/m2 in the atmosphere, and a relatively small TOA forcing (0.83 W/m2. Dust modifies the surface energy budget and atmospheric diabatic heating and hence causes lower atmospheric cooling in the daytime but warming in the nighttime. As a result, atmospheric stability is increased in the daytime and reduced in the nighttime, leading to a reduction of late afternoon precipitation by up to 0.14 mm/h (25% and an increase of nocturnal and early morning precipitation by up to 0.04 mm/h (45% over the WAM region. Dust-induced reduction of diurnal precipitation variation improves the simulated diurnal cycle of precipitation when compared to measurements. However, daily precipitation is only changed by a relatively small amount (−0.17 mm/day or −4%. The dust-induced change of WAM precipitation is not sensitive to interannual monsoon variability. On the other hand, sensitivity simulations show that, from weaker to stronger absorbing dust representing the uncertainty in dust solar absorptivity, dust longwave warming effect in the nighttime surpasses its shortwave cooling effect in the daytime at the surface, leading to a less stable atmosphere associated with more convective precipitation in the nighttime. As a result, the dust-induced change of daily WAM precipitation varies from a significant reduction of −0.52 mm/day (−12%, weaker absorbing dust to a small increase of 0.03 mm/day (1%, stronger absorbing dust. This variation originates from the competition between dust impact on daytime and nighttime

  12. Estimating some parameters of the equatorial ionosphere electrodynamics from ionosonde data in West Africa

    Science.gov (United States)

    Grodji, F. O.; Doumbia, V.; Boka, K.; Amory-Mazaudier, C.; Cohen, Y.; Fleury, R.

    2017-01-01

    During the International Equatorial Electrojet Year (IEEY), an IPS-42 ionosonde located at Korhogo (9.33°N, 5.42°W, -1.88° dip-lat) and a meridian chain of 10 magnetic stations were setup in West Africa (5°West longitude). In this work, some characteristic parameters of the equatorial electrojet were estimated on the basis of the IPS-42 ionosonde data at Korhogo during the years 1993 and 1994. The study consisted of determining the zonal electric field through an estimate of the plasma vertical drift velocity. The daytime plasma vertical drift velocity was estimated from the time rates of change of the F-layer virtual height variations and a correction term that takes into account the ionization production and recombination effects. This method resulted in an improved vertical drift velocity, which was found to be comparable to the results of previous studies. The estimated vertical drift velocity was used in a semi-empirical approach which involved the IRI-2012 model for the Pedersen and Hall conductivities and the IGRF-10 model for the geomagnetic main field intensity. Thus the zonal and polarization electric fields on one hand, and the eastward Pedersen, Hall and the equatorial electrojet current densities on the other hand, were estimated. Furthermore the integrated peak current density at the EEJ center was estimated from ionosonde observations and compared with that inferred from magnetometer data. The integrated EEJ peak current densities obtained from both experiments were found to be in the same order and their seasonal variations exhibit the same trends as well.

  13. Dust aerosol radiative effect and forcing over West Africa : A case study from the AMMA SOP

    Science.gov (United States)

    Lemaître, C.; Flamant, C.; Pelon, J.; Cuesta, J.; Chazette, P.; Raut, J. C.

    2009-04-01

    The massive transport of arid dust by the African easterly jet (AEJ) can impact the dynamic of the AEJ and modify the development of westerly African waves through modifications of horizontal temperature gradient. Hence, it is important to evaluate the radiative impact of dust and their effect on thermodynamical properties of the AEJ. In this presentation, the impact of aerosol on solar and infra-red fluxes and the heating rate due to dust over West Africa are investigated using the radiative code STREAMER, as well as space-borne and airborne lidars (CALIPSO and LEANDRE 2, respectively) as well as dropsonde observations acquired during the African Monsoon Multidisciplinary Analysis Special Observing Period. Aircraft operations were conducted on 13 and 14 June 2006, over Benin and Niger. On these days the dust observed over Benin and Niger originated from the Bodélé depression and from West Sudan. In this study, we use aerosol extinction coefficient derived from lidar, as well as temperature, pressure and water vapour profiles derived from dropsondes as inputs to STREAMER. The surface albedo is obtained with MODIS. A series of runs was carried out on 13 and 14 June 2006, around mid-day, to investigate the dust radiative forcing as a function of latitude, from 6°N to 15°N, i.e. between the vegetated coast of the Guinea Gulf and the arid Sahel. In the solar spectrum, the maximum heating rate associated with the dust plume on these days was comprised between 1.5 K/day and 3 K/day, depending on the aerosol load, over the entire Sudanian and Sahel regions as inferred from CALIPSO. Sensitivity studies to surface albedo, aerosol backscatter-to-extinction ratio, temperature and water vapor mixing ratio profiles were also conducted.

  14. Impact of land cover characterization on regional climate modeling over West Africa

    Science.gov (United States)

    Sylla, Mouhamadou Bamba; Pal, Jeremy S.; Wang, Guiling L.; Lawrence, Peter J.

    2016-01-01

    The impact of high resolution modern vegetation cover on the West African climate is examined using the International Centre for Theoretical Physics Regional Climate Model implementing the NCAR Community Land Model. Two high resolution 25 km long-term simulations driven by the output from a coarser 50-km resolution simulation are performed for the period 1998-2010. One high resolution simulation uses an earlier and coarser-resolution version of plant functional type distribution and leaf area index, while the other uses a more recent, higher-quality, and finer-resolution version of the data. The results indicate that the new land cover distribution substantially alters the distribution of temperature with warming in Central Nigeria, northern Gulf of Guinea and part of the Sahel due to the replacement of C4 grass with corn; and cooling along the coastlines of the Gulf of Guinea and in Central Africa due to the replacement of C4 grass with tropical broadleaf evergreen trees. Changes in latent heat flux appear to be largely responsible for these temperature changes with a net decrease (increase) in regions of warming (cooling). The improved land cover distribution also results in a wetter monsoon season. The presence of corn tends to favor larger precipitation amounts via more intense events, while the presence of tropical broadleaf evergreen trees tends to favor the occurrence of both more intense and more frequent events. The wetter conditions appear to be sustained via (1) an enhanced soil moisture feedback; and (2) elevated moisture transport due to increased low-level convergence in regions south of 10N where the most substantial land cover differences are present. Overall the changes induced by the improved vegetation cover improve, to some extent, the performance of the high resolution regional climate model in simulating the main West African summer monsoon features.

  15. The Quest for the Africa-Eurasia plate boundary West of the Strait of Gibraltar

    Science.gov (United States)

    Zitellini, N.

    2009-04-01

    A new swath bathymetry compilation of the Gulf of Cadiz Area and SW Iberia is presented. The new map is the result of a collaborative research performed after year 2000 by teams from 7 European countries and 14 research institutions. This new dataset allow for the first time to present and to discuss the missing link in the plate boundary between Eurasia and Africa in the Central Atlantic. A set of almost linear and sub parallel dextral strike-slip faults, the SWIM Faults (SWIM is the acronym of the ESF EuroMargins project "Earthquake and Tsunami hazards of active faults at the South West Iberian Margin: deep structure, high-resolution imaging and paleoseismic signature") was mapped using a the new swath bathymetry compilation available in the area. The SWIM Faults form a narrow band of deformation over a length of 600 km coincident with a small circle centred on the pole of rotation of Africa with respect to Eurasia, This narrow band of deformation connects the Gloria Fault to the Rif-Tell Fault Zone, two segments of the plate boundary between Africa and Eurasia. In addition, the SWIM faults cuts across the Gulf of Cadiz, in the Atlantic Ocean, where the 1755 Great Lisbon earthquake, M~8.5-8.7, and tsunami were generated, providing a new insights on its source location. SWIM Team: E. Gràcia (2), L. Matias (3), P. Terrinha (4), M.A. Abreu (5), G. DeAlteriis(6), J.P. Henriet (7), J.J. Dañobeitia (2), D.G. Masson (8), T. Mulder (9), R. Ramella (10), L. Somoza (11) and S. Diez (2) (2) Unitat de Tecnologia Marina (CSIC), Centre Mediterrani d'Investigacions Marines i Ambientals, Barcelona, Spain (3) Centro Geofísica da Universidade de Lisboa (CGUL, IDL), Lisboa, Portugal (4) National Institute for Engineering, Technology and Innovation (INETI, LATTEX), Departamento de Geologia Marinha, Amadora, Portugal (5) Estrutura de Missão para a Extensão da Plataforma Continental, Lisboa, Portugal (6) Geomare Sud IAMC, CNR, Napoli, Italy (7) Renard Centre of Marine Geology

  16. Biogeography and conservation of viperids from North-West Africa : an application of ecological niche-based models and GIS

    OpenAIRE

    J. C. Brito; Fahd, S.; Geniez, P.; Martinez-Freiria, F.; Pleguezuelos, J. M.; Trape, Jean-François

    2011-01-01

    North-West Africa is an outstanding region to study biogeographic patterns in biodiversity distribution. This study identifies biogeographic affinities and areas of probable occurrence for seven viperid snakes through the combination of high resolution presence data and environmental factors. Vipers exhibited distinct biogeographical affinities: Bitis arietans was mostly found along savannahs, Echis leucogaster along the Sahel/savannahs, Cerastes cerastes and C vipera throughout most desertic...

  17. The Impact of European Settlement within French West Africa. Did pre-colonial prosperous areas fall behind?

    OpenAIRE

    2008-01-01

    (english) Did colonization change the distribution of prosperity within French-speaking West Africa? Using a new database on both pre-colonial and colonial contexts, this paper gives evidence that Europeans tended to settle in more prosperous pre-colonial areas and that the European settlement had a strong positive impact on current outcomes, even in an extractive colonial context, resulting in a positive relationship between pre and post-colonial performances. I argue that the African hostil...

  18. Postprocessing of simulated precipitation for impact research in West Africa. Part I: model output statistics for monthly data

    Energy Technology Data Exchange (ETDEWEB)

    Paeth, Heiko [University of Wuerzburg, Institute of Geography, Wuerzburg (Germany)

    2011-04-15

    Rainfall represents an important factor in agriculture and food security, particularly, in the low latitudes. Climatological and hydrological studies which attempt to diagnose the hydrological cycle, require high-quality precipitation data. In West Africa, like in many parts of the world, the density of observational data is low and climate models are needed in order to perform homogeneous and complete data sets. However, climate models tend to produce systematic errors, especially, in terms of rainfall and cloud processes, which are usually approximated by physical parameterizations. In this study, a 25-year climatology of monthly precipitation in West Africa is presented, derived from a regional climate model simulation, and evaluated with respect to observational data. It is found that the model systematically underestimates the rainfall amount and variability and does not capture some details of the seasonal cycle in sub-Saharan West Africa. Thus, in its present form the precipitation climatology is not appropriate to draw a realistic picture of the hydrological cycle in West Africa nor to serve as input data for impact research. Therefore, a statistical model is developed in order to adjust the simulated rainfall data to the characteristics of observed precipitation. Assuming that the regional climate model is much more reliable in terms of atmospheric circulation and thermodynamics, model output statistics is used to correct simulated rainfall by means of other simulated parameters of the near-surface climate like temperature, sea level pressure and wind components. Monthly data is adjusted by a cross-validated multiple regression model. The resulting adjusted rainfall climatology reveals a substantial improvement in terms of the model deficiencies mentioned above. In part II of this publication, the characteristics of simulated daily precipitation is adapted to station data by applying a weather generator. Once the postprocessing approach is trained, it can

  19. A survey of UK healthcare workers' attitudes on volunteering to help with the Ebola outbreak in West Africa.

    Directory of Open Access Journals (Sweden)

    Lance Turtle

    Full Text Available To understand the barriers and enablers for UK healthcare workers who are considering going to work in the current Ebola outbreak in West Africa, but have not yet volunteered.After focus group discussions, and a pilot questionnaire, an anonymous survey was conducted using SurveyMonkey to determine whether people had considered going to West Africa, what factors might make them more or less likely to volunteer, and whether any of these were modifiable factors.The survey was publicised among doctors, nurses, laboratory staff and allied health professionals. 3109 people answered the survey, of whom 472 (15% were considering going to work in the epidemic but had not yet volunteered. 1791 (57.6% had not considered going, 704 (22.6% had considered going but decided not to, 53 (1.7% had volunteered to go and 14 (0.45% had already been and worked in the epidemic.For those considering going to West Africa, the most important factor preventing them from volunteering was a lack of information to help them decide; fear of getting Ebola and partners' concerns came next. Uncertainty about their potential role, current work commitments and inability to get agreement from their employer were also important barriers, whereas clarity over training would be an important enabler. In contrast, for those who were not considering going, or who had decided against going, family considerations and partner concerns were the most important factors.More UK healthcare workers would volunteer to help tackle Ebola in West Africa if there was better information available, including clarity about roles, cover arrangements, and training. This could be achieved with a well-publicised high quality portal of reliable information.

  20. Analysis of the Profitability and Marketing Channels of Rice: A Case Study of Menchum River Valley, North-West Region, Cameroon

    Directory of Open Access Journals (Sweden)

    Bime, M. J.

    2014-06-01

    Full Text Available The study carried out in Menchum River valley, Northwest Region of Cameroon had as objective to analyze the profitability and establish the marketing channels of rice in this zone. The study in-terviewed a total of 126 respondents, selected purposively and using the snow ball sampling tech-nique. Results showed that the main actors involved in the rice marketing channel were; produc-ers, wholesalers, hullers, retailers and consumers. The production and marketing of rice in the zone is a profitable venture. In terms of profitability in the rice business, millers obtain a relatively large profit margin as a percentage of the cost price (18.69% followed by the producers (12.77%, wholesalers (8.5% then retailers (8.33%. The average profit margin per bag of 50kg was; 1054.5FCFA (franc Communauté financière d'Afrique for producers, 1963.5 FCFA for millers; 1100 FCFA for the wholesalers and 1250FCFA for the retailers. The principal constraints identi-fied by the study that affects actors of the rice channel were, bad condition of the roads, lack of capital, poor quality of rice. It was recommended that there should be improvement in infrastruc-ture.

  1. Assessing the link between Atlantic Niño 1 and drought over West Africa using CORDEX regional climate models

    Science.gov (United States)

    Adeniyi, Mojisola Oluwayemisi; Dilau, Kabiru Alabi

    2016-12-01

    The skill of Coordinated Regional Climate Downscaling Experiment (CORDEX) models (ARPEGE, CCLM, HIRHAM, RACMO, REMO, PRECIS, RegCM3, RCA, WRF and CRCM) in simulating the climate (precipitation, temperature and drought) of West Africa is determined using a process-based metric. This is done by comparing the CORDEX models' simulated and observed correlation coefficients between Atlantic Niño Index 1 (ATLN1) and the climate over West Africa. Strong positive correlation is observed between ATLN1 and the climate parameters at the Guinea Coast (GC). The Atlantic Ocean has Niño behaviours through the ATLN indices which influence the climate of the tropics. Drought has distinct dipole structure of correlation with ATLN1 (negative at the Sahel); precipitation does not have distinct dipole structure of correlation, while temperature has almost a monopole correlation structure with ATLN1 over West Africa. The magnitude of the correlation increases with closeness to the equatorial eastern Atlantic. Correlations between ATLN1 and temperature are mostly stronger than those between ATLN1 and precipitation over the region. Most models have good performance over the GC, but ARPEGE has the highest skill at GC. The PRECIS is the most skilful over Savannah and RCA over Sahel. These models can be used to downscale the projected climate at the region of their highest skill.

  2. Desert dust impacts on human health: an alarming worldwide reality and a need for studies in West Africa

    Science.gov (United States)

    de Longueville, Florence; Ozer, Pierre; Doumbia, Seydou; Henry, Sabine

    2013-01-01

    High desert dust concentrations raise concerns about adverse health effects on human populations. Based on a systematic literature review, this paper aims to learn more about the relationship between desert dust and human health in the world and to analyse the place of West Africa as a study area of interest. Papers focussing on the potential relationship between dust and health and showing quantitative analyses, published between January 1999 and September 2011, were identified using the ISI Web of Knowledge database ( N = 50). A number of adverse health effects, including respiratory, cardiovascular and cardiopulmonary diseases, are associated with dust. This survey highlights obvious dust impacts on human health independently of the study area, health outcomes and method. Moreover, it reveals an imbalance between the areas most exposed to dust and the areas most studied in terms of health effects. None of these studies has been conducted in West Africa, despite the proximity of the Sahara, which produces about half of the yearly global mineral dust. In view of the alarming results in many parts of the world (Asia, Europe, America), this paper concludes by stressing the importance of carrying out impact studies of Saharan dust in West Africa, where dust events are more frequent and intense than anywhere else.

  3. A chaotic model for the epidemic of Ebola virus disease in West Africa (2013-2016).

    Science.gov (United States)

    Mangiarotti, Sylvain; Peyre, Marisa; Huc, Mireille

    2016-11-01

    An epidemic of Ebola Virus Disease (EVD) broke out in Guinea in December 2013. It was only identified in March 2014 while it had already spread out in Liberia and Sierra Leone. The spill over of the disease became uncontrollable and the epidemic could not be stopped before 2016. The time evolution of this epidemic is revisited here with the global modeling technique which was designed to obtain the deterministic models from single time series. A generalized formulation of this technique for multivariate time series is introduced. It is applied to the epidemic of EVD in West Africa focusing on the period between March 2014 and January 2015, that is, before any detected signs of weakening. Data gathered by the World Health Organization, based on the official publications of the Ministries of Health of the three main countries involved in this epidemic, are considered in our analysis. Two observed time series are used: the daily numbers of infections and deaths. A four-dimensional model producing a very complex dynamical behavior is obtained. The model is tested in order to investigate its skills and drawbacks. Our global analysis clearly helps to distinguish three main stages during the epidemic. A characterization of the obtained attractor is also performed. In particular, the topology of the chaotic attractor is analyzed and a skeleton is obtained for its structure.

  4. The impact of climate change on drylands. The case of West Africa

    Energy Technology Data Exchange (ETDEWEB)

    Dietz, T. [AGIDS-CERES, Amsterdam (Netherlands); Verhagen, J. [AB-DLO, Wageningen (Netherlands)

    1999-07-01

    The world's drylands can be characterised as semi-arid and sub-humid areas, with average annual P/ETP between 0.20 and 0.75. Average rainfall conditions restrict rain-dependent agriculture to mainly sorghum, millet and marginal maize cultivation as food crops and groundnuts and cotton as crops for agro-industry and for export. Animal husbandry based on cattle, goats and sheep can also be adding to food supply and cash income. In general, rainfed agriculture gives relatively low crop yields per hectare. Yearly rainfall variation can be considerable. Rainfall unreliability results in relatively high risks of crop failure due to drought. In West Africa, UNESCO's map of the world distribution of and regions shows a band of semi-arid conditions from Dakar in Senegal, via Ouagadougou in Burkina Faso to Niamey in Niger and further to Kano in Nigeria, the Sahel proper. South of this zone there is a band of sub-humid conditions. UNESCO's aridity assessment was based on rainfall and evapotranspiration conditions for mostly 1930-1960. Combined with assessments of land degradation and population density it formed the basis for the ICCD typology of all drylands in the tropics and subtropics. 22 refs.

  5. The economic impact of strategic risk on petroleum ventures: Examples from West Africa

    Energy Technology Data Exchange (ETDEWEB)

    Ethetton, L.K.; Brumbaugh, W.D.

    1995-12-31

    Strategic risks attend any and all business ventures. They arise from the nature of the particular business being pursued and the environment in which that business is being conducted. In the petroleum industry, considerable attention is devoted to quantifying technical risks, i.e., the risk of finding and producing hydrocarbons. However, strategic risks often impact economic viability more than technical asks. Accordingly, strategic risk analysis is critical to, realistically evaluating petroleum ventures in today`s turbulent business environment. While difficult to assess and quantify, strategic risks must be accorded equal status with technical risks. Competitor activity, contract terms, environmental sensitivity, political stability and market forces are typical strategic risks. A strategic risk system correlates a company`s capabilities with the quality of possible ventures. Internal strengths and weaknesses are thus matched against external opportunities and threats. This is known in the business literature as a SWOT analysis. The degree of strategic risk is then proportional to the mismatch between the SWOT elements. Such a mismatch was not recognized during exploration of the West Africa Aptian Salt Basins play in the 1980s. Angola, Congo and Gabon all contain examples where failure to consider strategic risk ultimately resulted in {open_quotes}Gambler`s Ruin{close_quotes}.

  6. HIV-2 integrase variation in integrase inhibitor-naive adults in Senegal, West Africa.

    Directory of Open Access Journals (Sweden)

    Geoffrey S Gottlieb

    Full Text Available BACKGROUND: Antiretroviral therapy for HIV-2 infection is hampered by intrinsic resistance to many of the drugs used to treat HIV-1. Limited studies suggest that the integrase inhibitors (INIs raltegravir and elvitegravir have potent activity against HIV-2 in culture and in infected patients. There is a paucity of data on genotypic variation in HIV-2 integrase that might confer intrinsic or transmitted INI resistance. METHODS: We PCR amplified and analyzed 122 HIV-2 integrase consensus sequences from 39 HIV-2-infected, INI-naive adults in Senegal, West Africa. We assessed genetic variation and canonical mutations known to confer INI-resistance in HIV-1. RESULTS: No amino acid-altering mutations were detected at sites known to be pivotal for INI resistance in HIV-1 (integrase positions 143, 148 and 155. Polymorphisms at several other HIV-1 INI resistance-associated sites were detected at positions 72, 95, 125, 154, 165, 201, 203, and 263 of the HIV-2 integrase protein. CONCLUSION: Emerging genotypic and phenotypic data suggest that HIV-2 is susceptible to the new class of HIV integrase inhibitors. We hypothesize that intrinsic HIV-2 integrase variation at "secondary" HIV-1 INI-resistance sites may affect the genetic barrier to HIV-2 INI resistance. Further studies will be needed to assess INI efficacy as part of combination antiretroviral therapy in HIV-2-infected patients.

  7. Climatic controls on West Nile virus and Sindbis virus transmission and outbreaks in South Africa.

    Science.gov (United States)

    Uejio, Christopher K; Kemp, Alan; Comrie, Andrew C

    2012-02-01

    The processes influencing the magnitude of West Nile virus (WNV) transmission from 1 year to the next require thorough investigation. The intensity of WNV transmission is related to the dynamics and interactions between the pathogen, vector, vertebrate hosts, and environment. Climatic variability is one process that can influence interannual disease transmission. South Africa has a long WNV and Sindbis virus (SINV) record where consistent climate and disease relationships can be identified. We relate climate conditions to historic mosquito infection rates. Next, we detect similar associations with reported human outbreaks dating back to 1941. Both concurrent summer precipitation and the change in summer precipitation from the previous to the current summer were strongly associated with WNV and SINV transmission and recorded human outbreaks. Each 100 mm interannual summer precipitation change increased WNV infection rates by 0.39 WNV-positive Culex univittatus/1000 tested Cx. univittatus. An improved understanding of biotic and abiotic disease transmission dynamics may help anticipate and mitigate future outbreaks.

  8. Evaluation of global rainfall Measurement for Hydrological Applications in West Africa : sensitivity tests in Benin

    Science.gov (United States)

    Viarre, J.; Gosset, M.; Peugeot, C.

    2011-12-01

    We carried out an evaluation of currently available -real time or post-calibrated- rainfall products in West Africa. The work is oriented towards highlighting their skills and relevance from the view point of a hydrological end-user. The study is based on the densily instrumented meso-scale basins from the AMMA-CATCH hydrometeorological observing system. On these sites long term observations of the various term of the continental water budget and hydrological processes studies have been carried out for more than a decade. We focus here on the upper Oueme basin site in Benin (Sudanese climate - 1200 mm annual rainfall). A distributed hydrological model, developed in this framework is used to illustrate the effects of satellite based rainfall errors or uncertainty on the simulated outflow. Non linearities cause the rainfall bias to be enhanced through propagation in the model, leading to strong biases in the outflow. In addition to the biases the model response is very sensitive to the distortion in the rainfall intensities probability distribution, that some rainfall products exhibit. The AMMA-CATCH densified gages networks and hydrometeorological measurements will be integrated in the MeghaTropiques ground validation plan and used to asses the quality of MT products at the one degree one daily scale and below.

  9. The potential of hybrid gravimetry for hydrology; application to a sudanian catchment (West Africa)

    Science.gov (United States)

    Hector, B.; Hinderer, J.; Séguis, L.

    2014-12-01

    The temporal and spatial variations of water storage are major unknowns of the hydrological cycle. They define the state of a hydrological system, which is critical for budget and process studies, like for instance threshold-governed subsurface redistribution, or water availability for evapotranspiration. Ground-based gravity measurements provide integrated (on a few tens of meters radius, the 'plot' scale) response to water storage changes (WSC) signal, which depends on mass and location changes of underground water. This information may be used for instance for process identification, for budget estimates, for specific yield retrieval, or for hypothesis testing through hydrological modeling. We try to address some of these issues based on our experience of a small catchment in the hard-rock Sudanian area of West-Africa (Djougou, northern Benin), where three state-of-art gravimeters have been deployed: a GWR superconducting gravimeter (SG), a Micro-g FG5 absolute gravimeter and a Scintrex CG5 microgravimeter. Spatial (i.e. at the catchment scale) distribution of WSC may be obtained using a hybrid gravimetry (CG5 + SG) approach. Significant hydrological information may be gained from gravity measurements, as long as these are analyzed in a joint approach, together with near-surface geophysics and hydrological monitoring for instance.

  10. Farmer-Managed Natural Regeneration Enhances Rural Livelihoods in Dryland West Africa

    Science.gov (United States)

    Weston, Peter; Hong, Reaksmey; Kaboré, Carolyn; Kull, Christian A.

    2015-06-01

    Declining agricultural productivity, land clearance and climate change are compounding the vulnerability of already marginal rural populations in West Africa. `Farmer-Managed Natural Regeneration' (FMNR) is an approach to arable land restoration and reforestation that seeks to reconcile sustained food production, conservation of soils, and protection of biodiversity. It involves selecting and protecting the most vigorous stems regrowing from live stumps of felled trees, pruning off all other stems, and pollarding the chosen stems to grow into straight trunks. Despite widespread enthusiasm and application of FMNR by environmental management and development projects, to date, no research has provided a measure of the aggregate livelihood impact of community adoption of FMNR. This paper places FMNR in the context of other agroforestry initiatives, then seeks to quantify the value of livelihood outcomes of FMNR. We review published and unpublished evidence about the impacts of FMNR, and present a new case study that addresses gaps in the evidence-base. The case study focuses on a FMNR project in the district of Talensi in the semi-arid Upper East Region in Ghana. The case study employs a social return on investment analysis, which identifies proxy financial values for non-economic as well as economic benefits. The results demonstrate income and agricultural benefits, but also show that asset creation, increased consumption of wild resources, health improvements, and psycho-social benefits created more value in FMNR-adopting households during the period of the study than increases in income and agricultural yields.

  11. Toward a Socio-Territorial Approach to Health: Health Equity in West Africa

    Science.gov (United States)

    Vialard, Lucie; Squiban, Clara; Fournet, Florence; Salem, Gérard; Foley, Ellen E.

    2017-01-01

    This study contributes to the literature about the effects of space and place on health by introducing a socio-territorial approach to urban health disparities in West Africa. It explores how urban spaces, specifically neighbourhoods, are shaped by social and economic relations and strategies of territorial control. We examine the potential influence of socio-territorial processes on vulnerability to disease, access to medical care, healthscapes, and illness experiences. Our research was conducted in Senegal and relied on a mixed methods design. We identified four neighbourhoods that represent the socio-spatial heterogeneity of the city of Saint-Louis and utilized the following methods: geographic and anthropological field research, household surveys, health knowledge and behaviour surveys, clinical exams, and illness interviews. Our results highlight the socio-territorial processes at work in each neighbourhood, clinical findings on three health measures (overweight, high blood pressure, and hyperglycaemia) and health experiences of individuals with hypertension or type II diabetes. We found significant differences in the prevalence of the three health measures in the study sites, while experiences managing hypertension and diabetes were similar. We conclude that a socio-territorial approach offers insight into the complex constellation of forces that produce health disparities in urban settings. PMID:28117751

  12. Subsurface combustion in Mali: Refutation of the active volcanism hypothesis in West Africa

    Science.gov (United States)

    Svensen, Henrik; Dysthe, Dag Kristian; Bandlien, Einar H.; Sacko, Samba; Coulibaly, Henri; Planke, Sverre

    2003-07-01

    Surface heat anomalies have been known in the Timbuktu region in northern Mali for more than a century. Since about 1960, several authors have argued that these heat anomalies are caused by incipient volcanic and hydrothermal activity. Surface temperatures as high as 765 °C were measured locally in January 2002, and smoke emanated from holes and fractures in the ground. We demonstrate that subsurface combustion of organic material is the source of the heat and the gases. Several square kilometers are currently active or have been affected by subsurface fires since 2001. Self-ignition during biological degradation of organic-rich layers in the lacustrine deposits is the most likely mechanism that started the subsurface combustion that caused the heat anomalies in the area. An important consequence of this conclusion is that West Africa should still be regarded as volcanologically inactive, and that possible reactivations of the major EW-trending Guinean-Nubian lineament are not associated with volcanism. We suggest that the subsurface combustion in the Timbuktu region today represents a phenomenon with a very long record in the Trans-Saharan region.

  13. On the tectonics and metallogenesis of West Africa: a model incorporating new geophysical data

    Science.gov (United States)

    Hastings, David A.

    1982-01-01

    The gold, diamond and manganese deposits of Ghana have attracted commercial interest, but appropriate geophysical data to delineate the tectonic setting of these and other deposits have been lacking until recently. Recent gravity surveys, however, now cover about 75% of the country. When used in a synthesis of the sometimes contradictory existing theories about the geology and metallogenesis of West Africa, the available gravity, magnetic, and seismic data lead to a preliminary tectonic model that postulates rifting at the time of the (1800-2000 m.y. old) Eburnean orogeny and is consistent with the occurrences of mineral deposits in the region. In this model, diamond-bearing kimberlites formed during the commencement of rifting during the Eburnean orogenesis. Later emplacement of kimberlites was associated with the initiation of Mesozoic rifting of Gondwanaland. Primary gold vein deposits were probably formed by the migration of hydrothermal fluids (associated with the formation of granitoids) into dilatant zones, such as rift-related faults and anticlinal axial areas, toward the end of the Eburnean orogeny. At this time, the major concordant granitoids were formed, with smaller plutonic granitoids forming on the fringes of the concordant masses as partial melting fractions of the latter. Sedimentary manganese deposits were formed along the margins of rift lakes toward the end of the orogeny.

  14. Population genetic structure of Plasmodium falciparum across a region of diverse endemicity in West Africa

    Directory of Open Access Journals (Sweden)

    Mobegi Victor A

    2012-07-01

    Full Text Available Abstract Background Malaria parasite population genetic structure varies among areas of differing endemicity, but this has not been systematically studied across Plasmodium falciparum populations in Africa where most infections occur. Methods Ten polymorphic P. falciparum microsatellite loci were genotyped in 268 infections from eight locations in four West African countries (Republic of Guinea, Guinea Bissau, The Gambia and Senegal, spanning a highly endemic forested region in the south to a low endemic Sahelian region in the north. Analysis was performed on proportions of mixed genotype infections, genotypic diversity among isolates, multilocus standardized index of association, and inter-population differentiation. Results Each location had similar levels of pairwise genotypic diversity among isolates, although there were many more mixed parasite genotype infections in the south. Apart from a few isolates that were virtually identical, the multilocus index of association was not significant in any population. Genetic differentiation between populations was low (most pairwise FST values  Conclusions Although proportions of mixed genotype infections varied with endemicity as expected, population genetic structure was similar across the diverse sites. Very substantial reduction in transmission would be needed to cause fragmented or epidemic sub-structure in this region.

  15. A new anoplocephalid (Cestoda) from Tarentola parvicarinata (Lacertilia: Gekkonidae) in Senegal (West Africa).

    Science.gov (United States)

    Mašová, Sárka; Tenora, František; Baruš, Vlastimil; Koubek, Petr

    2010-10-01

    The present study presents the description of Oochoristica beveridgei n. sp. (Linstowiinae Fuhrmann, 1907). The species was found in the small intestine of Tarentola parvicarinata Joger (Gekkonidae) in East Senegal (West Africa). Among known species of Oochoristica Lühe, 1898, O. beveridgei is most similar to Oochoristica junkea (Johri, 1950) Schmidt, 1986, found in Gekko gecko (Linnaeus) from India. A common feature of both species is the location of the cirrus sac, which lies anterior to the poral part of the ovary. The new species differs from O. junkea in having a higher number of testes, different testes arrangement, wider cirrus sac, and a different shape of ovary. The position of the cirrus sac in O. beveridgei is also similar to that found in Oochoristica gallica Dollfus, 1954, whose host is Psammodromus hispanicus Fitzinger (Lacertidae) from Morocco. The new species differs from O. gallica in that it possesses fewer testes and that these testes have a different arrangement. The location of the cirrus sac in O. beveridgei is also similar to that seen in Oochoristica bivitellolobata Loewen, 1940, whose host is Cnemidophorus sexlineatus (Linnaeus) (Teiidae) from the United States. The latter species has a higher number of testes, with only half of the cirrus sac located anterior to the poral part of the ovary, and possesses a divided vitellarium.

  16. The Global Politics of Gay Rights: The Straining Relations between the West and Africa

    Directory of Open Access Journals (Sweden)

    Hakeem Onapajo

    2016-01-01

    Full Text Available This article analyses the contemporary global politics of gay rights as it relates to the straining relations between the Western powers and many African states that oppose sexual minorities’ rights. While the West (with emphasis on the United States, EU, and Britain advocates for the protection of gay rights in the world, Africa provides the largest concentration of states opposed to them. Therefore, there has been rising tension between both regions. This became more apparent after Nigeria and Uganda, respectively, signed their anti-gay bills into law in January and February 2014. In response to this, the Western powers decided to take some punitive measures, especially imposition of sanctions, against the countries to pressurise them to repeal their laws. In an unusual manner, the African states are radically determined to go ahead with their anti-gay laws in open defiance to the demands of the Western powers. This development, which is informed by a number of factors, shows a rather new pattern of behaviour by African states in global politics.

  17. IASI-derived Surface Temperature Under Dusty Conditions: Application to the West Africa Region.

    Science.gov (United States)

    Mechri, Rihab; Capelle, Virginie; Chedin, Alain

    2016-04-01

    Giving access to energy and water budgets, Surface Temperature (ST) is considered as a key variable for a wide range of applications in particular for meteorology and climatology. An accurate knowledge of this variable should significantly improve the monitoring of numerous atmospheric and surface processes as well as their interactions. Even-though satellite sensors bring ST global fields at different spatial and temporal scales, the accuracy of these products is still questionable especially over land or for complex atmospheric conditions (presence of clouds, of aerosols, etc.). At LMD, the ST is determined through the simultaneous "Look-up-Table" inversion of satellite METOP/IASI radiances in terms of Aerosol Optical Depth (AOD), dust layer mean altitude and surface temperature . The main aim of this work is to validate IASI ST product and to analyze its spatial and temporal variability, in particular in the presence of dust aerosols. This approach has been first applied to the West Africa region. The accuracy of this ST product will be assessed in terms of bias and standard deviation against ST products from ECMWF forecast, from other satellite products (MODIS AQUA/TERRA, AATSR,…) and from in-situ measurements for different periods ranging from July 2007 to today according to the availability of these validation data.

  18. Microcredit in West Africa: how small loans make a big impact on poverty.

    Science.gov (United States)

    Gbezo, B E

    1999-01-01

    This article examines the impact of microfinancing schemes in West Africa and the role of the International Labor Organization (ILO) in their development. Microfinancing or microcredit schemes are meant to create the kind of jobs that can keep households severely hit by the economic crisis afloat. They affect not only the financial, but also the agricultural, crafts, financing of social economy, and social protection sectors of the society. Thus, they contribute to improved access to basic social, health and family planning services and to drinking water. The challenge then, is for institutes to adopt microfinancing and to reach out to more than 100 million families in the region. To realize this, nongovernmental organizations are setting up as veritable microfinancing institutions, which are able to realize the resulting benefits so as to be economically viable. In the context of its role in the development of microfinancing schemes, ILO manages a portfolio of technical cooperation and research projects aimed at identifying and removing constraints in the access to credit, savings, insurance, and other financial services through its Social Finance Unit. In addition, ILO is promoting women's entrepreneurship through the International Small Enterprise Programme and the International Programme on More and Better Jobs for Women.

  19. Farmer-managed natural regeneration enhances rural livelihoods in dryland west Africa.

    Science.gov (United States)

    Weston, Peter; Hong, Reaksmey; Kaboré, Carolyn; Kull, Christian A

    2015-06-01

    Declining agricultural productivity, land clearance and climate change are compounding the vulnerability of already marginal rural populations in West Africa. 'Farmer-Managed Natural Regeneration' (FMNR) is an approach to arable land restoration and reforestation that seeks to reconcile sustained food production, conservation of soils, and protection of biodiversity. It involves selecting and protecting the most vigorous stems regrowing from live stumps of felled trees, pruning off all other stems, and pollarding the chosen stems to grow into straight trunks. Despite widespread enthusiasm and application of FMNR by environmental management and development projects, to date, no research has provided a measure of the aggregate livelihood impact of community adoption of FMNR. This paper places FMNR in the context of other agroforestry initiatives, then seeks to quantify the value of livelihood outcomes of FMNR. We review published and unpublished evidence about the impacts of FMNR, and present a new case study that addresses gaps in the evidence-base. The case study focuses on a FMNR project in the district of Talensi in the semi-arid Upper East Region in Ghana. The case study employs a social return on investment analysis, which identifies proxy financial values for non-economic as well as economic benefits. The results demonstrate income and agricultural benefits, but also show that asset creation, increased consumption of wild resources, health improvements, and psycho-social benefits created more value in FMNR-adopting households during the period of the study than increases in income and agricultural yields.

  20. Integrated Flood Risk Assessment of Rural Communities in the Oti River Basin, West Africa

    Directory of Open Access Journals (Sweden)

    Kossi Komi

    2016-11-01

    Full Text Available Flood damage in West Africa has increased appreciably during the last two decades. Poor communities are more at risk due to the vulnerability of their livelihoods, especially in rural areas where access to services and infrastructures is limited. The aim of this paper is to identify the main factors that contribute to flood risk of rural communities in the Oti River Basin, Togo. A community-based disaster risk index model is applied. The analyses use primary data collected through questionnaires during fieldwork, the analytic hierarchy process (AHP method, population and housing census data and flood hazard mapping of the study area. The results showed a moderate level of flood risk despite a high level of hazard and vulnerability for all investigated communities. In addition, the results suggest that decreasing vulnerability through creation of new income-generating opportunities and increasing capacity of communities to manage their own flood risk should be paramount in order to reduce flood risk in the study area. The results of this work contribute to the understanding of flood risk and can be used to identify, assess, and compare flood-prone areas, as well as simulating the impacts of flood management measures in the Oti River Basin.

  1. Deciphering Dynamics of Recent Epidemic Spread and Outbreak in West Africa: The Case of Ebola Virus

    Science.gov (United States)

    Upadhyay, Ranjit Kumar; Roy, Parimita

    Recently, the 2014 Ebola virus (EBOV) outbreak in West Africa was the largest outbreak to date. In this paper, an attempt has been made for modeling the virus dynamics using an SEIR model to better understand and characterize the transmission trajectories of the Ebola outbreak. We compare the simulated results with the most recent reported data of Ebola infected cases in the three most affected countries Guinea, Liberia and Sierra Leone. The epidemic model exhibits two equilibria, namely, the disease-free and unique endemic equilibria. Existence and local stability of these equilibria are explored. Using central manifold theory, it is established that the transcritical bifurcation occurs when basic reproduction number passes through unity. The proposed Ebola epidemic model provides an estimate to the potential number of future cases. The model indicates that the disease will decline after peaking if multisectorial and multinational efforts to control the spread of infection are maintained. Possible implication of the results for disease eradication and its control are discussed which suggests that proper control strategies like: (i) transmission precautions, (ii) isolation and care of infectious Ebola patients, (iii) safe burial, (iv) contact tracing with follow-up and quarantine, and (v) early diagnosis are needed to stop the recurrent outbreak.

  2. A chaotic model for the epidemic of Ebola virus disease in West Africa (2013-2016)

    Science.gov (United States)

    Mangiarotti, Sylvain; Peyre, Marisa; Huc, Mireille

    2016-11-01

    An epidemic of Ebola Virus Disease (EVD) broke out in Guinea in December 2013. It was only identified in March 2014 while it had already spread out in Liberia and Sierra Leone. The spill over of the disease became uncontrollable and the epidemic could not be stopped before 2016. The time evolution of this epidemic is revisited here with the global modeling technique which was designed to obtain the deterministic models from single time series. A generalized formulation of this technique for multivariate time series is introduced. It is applied to the epidemic of EVD in West Africa focusing on the period between March 2014 and January 2015, that is, before any detected signs of weakening. Data gathered by the World Health Organization, based on the official publications of the Ministries of Health of the three main countries involved in this epidemic, are considered in our analysis. Two observed time series are used: the daily numbers of infections and deaths. A four-dimensional model producing a very complex dynamical behavior is obtained. The model is tested in order to investigate its skills and drawbacks. Our global analysis clearly helps to distinguish three main stages during the epidemic. A characterization of the obtained attractor is also performed. In particular, the topology of the chaotic attractor is analyzed and a skeleton is obtained for its structure.

  3. Regional-scale climate-variability synchrony of cholera epidemics in West Africa

    Directory of Open Access Journals (Sweden)

    Petit Michel

    2007-03-01

    Full Text Available Abstract Background The relationship between cholera and climate was explored in Africa, the continent with the most reported cases, by analyzing monthly 20-year cholera time series for five coastal adjoining West African countries: Côte d'Ivoire, Ghana, Togo, Benin and Nigeria. Methods We used wavelet analyses and derived methods because these are useful mathematical tools to provide information on the evolution of the periodic component over time and allow quantification of non-stationary associations between time series. Results The temporal variability of cholera incidence exhibits an interannual component, and a significant synchrony in cholera epidemics is highlighted at the end of the 1980's. This observed synchrony across countries, even if transient through time, is also coherent with both the local variability of rainfall and the global climate variability quantified by the Indian Oscillation Index. Conclusion Results of this study suggest that large and regional scale climate variability influence both the temporal dynamics and the spatial synchrony of cholera epidemics in human populations in the Gulf of Guinea, as has been described for two other tropical regions of the world, western South America and Bangladesh.

  4. Modelling social vulnerability in sub-Saharan West Africa using a geographical information system

    Directory of Open Access Journals (Sweden)

    Olanrewaju Lawal

    2015-02-01

    Full Text Available In recent times, disasters and risk management have gained significant attention, especially with increasing awareness of the risks and increasing impact of natural and other hazards especially in the developing world. Vulnerability, the potential for loss of life or property from disaster, has biophysical or social dimensions. Social vulnerability relates to societal attributes which has negative impacts on disaster outcomes. This study sought to develop a spatially explicit index of social vulnerability, thus addressing the dearth of research in this area in sub-Saharan Africa. Nineteen variables were identified covering various aspects. Descriptive analysis of these variables revealed high heterogeneity across the South West region of Nigeria for both the state and the local government areas (LGAs. Feature identification using correlation analysis identified six important variables. Factor analysis identified two dimensions, namely accessibility and socioeconomic conditions, from this subset. A social vulnerability index (SoVI showed that Ondo and Ekiti have more vulnerable LGAs than other states in the region. About 50% of the LGAs in Osun and Ogun have a relatively low social vulnerability. Distribution of the SoVI shows that there are great differences within states as well as across regions. Scores of population density, disability and poverty have a high margin of error in relation to mean state scores. The study showed that with a geographical information system there are opportunities to model social vulnerability and monitor its evolution and dynamics across the continent.

  5. Oxygen, hydrogen, and helium isotopes for investigating groundwater systems of the Cape Verde Islands, West Africa

    Science.gov (United States)

    Heilweil, V.M.; Solomon, K.D.; Gingerich, S.B.; Verstraeten, Ingrid M.

    2009-01-01

    Stable isotopes (??18O, ??2H), tritium (3H), and helium isotopes (3He, 4He) were used for evaluating groundwater recharge sources, flow paths, and residence times of three watersheds in the Cape Verde Islands (West Africa). Stable isotopes indicate the predominance of high-elevation precipitation that undergoes little evaporation prior to groundwater recharge. In contrast to other active oceanic hotspots, environmental tracers show that deep geothermal circulation does not strongly affect groundwater. Low tritium concentrations at seven groundwater sites indicate groundwater residence times of more than 50 years. Higher tritium values at other sites suggest some recent recharge. High 4He and 3He/4He ratios precluded 3H/3He dating at six sites. These high 3He/4He ratios (R/Ra values of up to 8.3) are consistent with reported mantle derived helium of oceanic island basalts in Cape Verde and provided end-member constraints for improved dating at seven other locations. Tritium and 3H/3He dating shows that S??o Nicolau Island's Ribeira Faj?? Basin has groundwater residence times of more than 50 years, whereas Fogo Island's Mosteiros Basin and Santo Ant??o Island's Ribeira Paul Basin contain a mixture of young and old groundwater. Young ages at selected sites within these two basins indicate local recharge and potential groundwater susceptibility to surface contamination and/or salt-water intrusion. ?? Springer-Verlag 2009.

  6. Toward a Socio-Territorial Approach to Health: Health Equity in West Africa

    Directory of Open Access Journals (Sweden)

    Lucie Vialard

    2017-01-01

    Full Text Available This study contributes to the literature about the effects of space and place on health by introducing a socio-territorial approach to urban health disparities in West Africa. It explores how urban spaces, specifically neighbourhoods, are shaped by social and economic relations and strategies of territorial control. We examine the potential influence of socio-territorial processes on vulnerability to disease, access to medical care, healthscapes, and illness experiences. Our research was conducted in Senegal and relied on a mixed methods design. We identified four neighbourhoods that represent the socio-spatial heterogeneity of the city of Saint-Louis and utilized the following methods: geographic and anthropological field research, household surveys, health knowledge and behaviour surveys, clinical exams, and illness interviews. Our results highlight the socio-territorial processes at work in each neighbourhood, clinical findings on three health measures (overweight, high blood pressure, and hyperglycaemia and health experiences of individuals with hypertension or type II diabetes. We found significant differences in the prevalence of the three health measures in the study sites, while experiences managing hypertension and diabetes were similar. We conclude that a socio-territorial approach offers insight into the complex constellation of forces that produce health disparities in urban settings.

  7. Logistics Aspect of Offshore Support Vessels on the West Africa Market

    Directory of Open Access Journals (Sweden)

    Ivica Skoko

    2013-12-01

    Full Text Available With the rapidly increasing global energy needs, offshore oil production has become an attractive source of energy. Supplying offshore oil production installations is a complex logistics problem that hinges on many factors with significant uncertainties. So, it is critical to provide the necessary supplies and services without interruption. In a typical offshore oil production effort, oil companies charter most or all drilling units as well as offshore supply vessels (OSV. The type and duration of charter contract has direct impact on the project budget as vessels market is closely correlated with the world market crude oil price which can have daily significant fluctuations. As the region of West Africa is one of the world’s busiest offshore exploration and oil production markets employing 12% of the world’s fleet, exploring its issues, was taken to study the relations between daily OSV rates and crude oil price. The research results presented in this paper show correlation between OSV daily rates and crude oil price with broader fluctuations in crude oil price. 

  8. Marine incursion: the freshwater herring of Lake Tanganyika are the product of a marine invasion into west Africa.

    Directory of Open Access Journals (Sweden)

    Anthony B Wilson

    Full Text Available The spectacular marine-like diversity of the endemic fauna of Lake Tanganyika, the oldest of the African Great Lakes, led early researchers to suggest that the lake must have once been connected to the ocean. Recent geophysical reconstructions clearly indicate that Lake Tanganyika formed by rifting in the African subcontinent and was never directly linked to the sea. Although the Lake has a high proportion of specialized endemics, the absence of close relatives outside Tanganyika has complicated phylogeographic reconstructions of the timing of lake colonization and intralacustrine diversification. The freshwater herring of Lake Tanganyika are members of a large group of pellonuline herring found in western and southern Africa, offering one of the best opportunities to trace the evolutionary history of members of Tanganyika's biota. Molecular phylogenetic reconstructions indicate that herring colonized West Africa 25-50MYA, at the end of a major marine incursion in the region. Pellonuline herring subsequently experienced an evolutionary radiation in West Africa, spreading across the continent and reaching East Africa's Lake Tanganyika during its early formation. While Lake Tanganyika has never been directly connected with the sea, the endemic freshwater herring of the lake are the descendents of an ancient marine incursion, a scenario which may also explain the origin of other Tanganyikan endemics.

  9. University-level nutrition training in West Africa: cost and financing issues

    Directory of Open Access Journals (Sweden)

    Roger Sodjinou

    2015-11-01

    Full Text Available Background: There is a serious shortage of skilled nutrition professionals in West Africa. Investing in nutrition training is one of the strategies for strengthening the human resource base in nutrition. However, little is known about how nutrition training in the region is financed and the levels of tuition fees charged. The purpose of this study was to provide a comprehensive assessment about the levels of tuition fees charged for nutrition training in the West Africa region and to determine to what extent this is of reach to the average student. Methodology: The data for this study were obtained from 74 nutrition degree programs operating in nine West African countries in 2013 through semi-structured interviews during on-site visits or through self-administered questionnaires. They included the age of the programs, school ownership, tuition fees, financial assistance, and main sources of funding. Tuition fees (in 2013 US$ were expressed per program to enable uniformity and comparability. Simple descriptive and bivariate analyses were performed. Results: Results from 74 nutrition training programs in nine countries showed a wide variation in tuition fees within and between countries. The tuition fees for bachelor's, master's, and doctoral programs, respectively, ranged from 372 to 4,325 (mean: 2,353; 162 to 7,678 (mean: 2,232; and 369 to 5,600 (mean: 2,208. The tuition fees were significantly higher (p<0.05 in private institutions than in public institutions (mean: US$3,079 vs. US$2,029 for bachelor's programs; US$5,118 vs. US$1,820 for master's programs; and US$3,076 vs. US$1,815 for doctoral programs. The difference in the tuition fees between Francophone and Anglophone countries was not statistically significant (mean: US$2,570 vs. US$2,216 for bachelor's programs; US$2,417 vs. US$2,147 for master's programs; US$3,285 vs. US$2,055 for doctoral programs. In most countries, the tuition fees appeared to be out of reach of the average student

  10. Review of West Africa. Elephant hunting is starting again. More numerous and various operators. Angola, an expansion with large fields. Congo, after Nkossa. Girassol: the selected companies. A controversial project, the Chad-Cameroon pipeline. Gabon, no discovery since 8 years. Nigeria, every man for himself. Ivory Coast, a more attractive legislation. The African legislation is evolving. Bouygues Offshore is on tracks for deep sea. The African contracts for ETPM; Dossier Afrique de l'Ouest. La chasse a l'elephant reprend de plus belle. Des acteurs plus nombreux et plus divers. Angola - une expansion par grands champs. Congo - l'apres Nkossa. Girassol: les entreprises retenues. Un projet controverse - le pipeline Tchad-Cameroun. Gabon - pas de decouvertes depuis huit ans. Nigeria - chacun pour soi. Cote d'Ivoire - une legislation plus attractive. La legislation petroliere africaine evolue. Bouygues Offshore en piste pour la mer profonde. Les contrats africains d'ETPM

    Energy Technology Data Exchange (ETDEWEB)

    Anon.

    1998-05-01

    A review of the petroleum and gas reserves, production and exploration situation in the various West African countries is presented with maps and statistics. It is shown that numerous projects are developed, especially in offshore Guinea Gulf, with small and large petroleum companies rushing to Nigeria, Angola, Gabon, etc. The various projects and companies selected for Angola, Congo, Gabon and Nigeria oil fields are discussed, together with the prospectives for Ivory Coast and the evolution of legislation related to petroleum in Africa. Bouygues Offshore's strategy in the Guinea Gulf is exposed and the african contracts for the platform and pipeline specialist ETPM are detailed.

  11. Timing and tectonic implications of the Pan-African Bangangte syenomonzonite, West Cameroon: Constraints from in-situ zircon U-Pb age and Hf-O isotopes

    Science.gov (United States)

    Tchouankoue, Jean Pierre; Li, Xian-Hua; Belnoun, Rose Noel Ngo; Mouafo, Lucas; Ferreira, Valderez Pinto

    2016-12-01

    The Bangangte pluton is a SW-NE elongated (5 × 20 km) massif located in the southeastern part of the Pan-African North Equatorial Fold Belt in Cameroon, consisting of two units with dominant monzonites in the south and syenites in the north. SIMS U-Pb zircon dating yields consistent emplacement ages of 585 ± 4 Ma and 583 ± 4 Ma for the southern unit and the northern unit, respectively. The Bangangte rocks display typical shoshonitic compositions characterized by Na2O + K2O > 5 wt%, K2O/Na2O ∼2, enrichment in LILE and LREE, but depletion in HFSE. Rocks from both units have similar O-Hf isotopes, with the monzonite zircons from the southern unit showing slightly higher δ18O (7.0 ± 0.4‰) but lower εHf(t) (-15.3 ± 1.4) value than the syenite zircons from southern unit (δ18O = 6.0 ± 0.4‰; εHf(t) = -14.0 ± 2.0). They were generated by partial melting of an enriched mantle source metasomatized by previous subduction processes, accompanied by crystal fractionation of pyroxene, Ti-Fe oxides and apatite, as well as crustal contamination to varying degrees. These rocks display a transitional geochemical feature of the subduction-related and within-plate shoshonites, suggesting that they were most likely emplaced in a post-collisional setting at the waning stage of the Pan-African orogeny.

  12. Morpho-physical variation of fruits and impact on almond production of djansang (Ricinodendron heudelotii Baill.) in west and centre of Cameroon.

    Science.gov (United States)

    Néhémie, Donfagsiteli Tchinda; Fotso; Sanonne; Dénis, Omokolo Ndoumou

    2007-09-01

    The aim of this study were to describe different forms of fruits and the establishment of correlation between the different morpho-physical parameters in view of evaluating their incidence on production of almonds in Ricinodendron heudolotii in three localities (Balamba, Mbalmayo, Santchou) in Cameroon. Tropical forest trees belonging to the Euphorbiaceae family, R. heudelotii is used by the local population in traditional medicine and as lipidic source. Fruits randomly harvested in these three localities have revealed six types namely: one new type constitute of four seeded fruit with four lobes and five previous type constitute of single seeded fruit with one lobe; single seeded fruit with one aborted lobe; two seeded fruit with two lobes; two seeded fruit with unequally developed lobes; three seeded fruit with three lobes. This variability is expressed by differences at the level of morphological parameters (mass of fruit and seed) and physical parameters (thickness of shell, ratio of longitudinal diameter and cross diameter section of seeds, capacity to liberate almonds). Analyses of variance, correlation and principal component have showed that, seeds extracted from fruits of Mbalmayo have shell thicker whereby those of Santchou liberate much shell. In the same way, accession of Mbalmayo has a total mass for 1500 fruits estimated 1.5 times superior to those of Balamba and 1.19 time superior to those of Santchou. In fact, study of morpho-physical parameter shows that to choose the fruits having a high capacity to liberate almond, ellipsoid-oblate form of the seeds and thickness of shell are good indicators and for this effect, accession of Santchou is recommended. Accessions of Balamba and Santchou having less rate of seed abortion are more productive.

  13. Characteristics of HIV-2 and HIV-1/HIV-2 Dually Seropositive Adults in West Africa Presenting for Care and Antiretroviral Therapy

    DEFF Research Database (Denmark)

    Ekouevi, Didier K; Coffie, Patrick A; Messou, Eugene

    2013-01-01

    HIV-2 is endemic in West Africa. There is a lack of evidence-based guidelines on the diagnosis, management and antiretroviral therapy (ART) for HIV-2 or HIV-1/HIV-2 dual infections. Because of these issues, we designed a West African collaborative cohort for HIV-2 infection within the framework...

  14. Implications of the cattle trade network in Cameroon for regional disease prevention and control

    Science.gov (United States)

    Motta, Paolo; Porphyre, Thibaud; Handel, Ian; Hamman, Saidou M.; Ngu Ngwa, Victor; Tanya, Vincent; Morgan, Kenton; Christley, Rob; Bronsvoort, Barend M. deC.

    2017-01-01

    Movement of live animals is a major risk factor for the spread of livestock diseases and zoonotic infections. Understanding contact patterns is key to informing cost-effective surveillance and control strategies. In West and Central Africa some of the most rapid urbanization globally is expected to increase the demand for animal-source foods and the need for safer and more efficient animal production. Livestock trading points represent a strategic contact node in the dissemination of multiple pathogens. From October 2014 to May 2015 official transaction records were collected and a questionnaire-based survey was carried out in cattle markets throughout Western and Central-Northern Cameroon. The data were used to analyse the cattle trade network including a total of 127 livestock markets within Cameroon and five neighboring countries. This study explores for the first time the influence of animal trade on infectious disease spread in the region. The investigations showed that national borders do not present a barrier against pathogen dissemination and that non-neighbouring countries are epidemiologically connected, highlighting the importance of a regional approach to disease surveillance, prevention and control. Furthermore, these findings provide evidence for the benefit of strategic risk-based approaches for disease monitoring, surveillance and control, as well as for communication and training purposes through targeting key regions, highly connected livestock markets and central trading links. PMID:28266589

  15. Implications of the cattle trade network in Cameroon for regional disease prevention and control

    Science.gov (United States)

    Motta, Paolo; Porphyre, Thibaud; Handel, Ian; Hamman, Saidou M.; Ngu Ngwa, Victor; Tanya, Vincent; Morgan, Kenton; Christley, Rob; Bronsvoort, Barend M. Dec.

    2017-03-01

    Movement of live animals is a major risk factor for the spread of livestock diseases and zoonotic infections. Understanding contact patterns is key to informing cost-effective surveillance and control strategies. In West and Central Africa some of the most rapid urbanization globally is expected to increase the demand for animal-source foods and the need for safer and more efficient animal production. Livestock trading points represent a strategic contact node in the dissemination of multiple pathogens. From October 2014 to May 2015 official transaction records were collected and a questionnaire-based survey was carried out in cattle markets throughout Western and Central-Northern Cameroon. The data were used to analyse the cattle trade network including a total of 127 livestock markets within Cameroon and five neighboring countries. This study explores for the first time the influence of animal trade on infectious disease spread in the region. The investigations showed that national borders do not present a barrier against pathogen dissemination and that non-neighbouring countries are epidemiologically connected, highlighting the importance of a regional approach to disease surveillance, prevention and control. Furthermore, these findings provide evidence for the benefit of strategic risk-based approaches for disease monitoring, surveillance and control, as well as for communication and training purposes through targeting key regions, highly connected livestock markets and central trading links.

  16. The Latitudinal Gradient of Rainfall, Mineralogy, Albedo and Magnetic Susceptibility in West Africa

    Science.gov (United States)

    Williams, E. R.; Balsam, W.; Schaaf, C.; Yang, X.; Zhang, Q.; Ji, J.; Rossman, G.; Garimella, S.; Oldfield, F.; Lyons, J. R.; Ellwood, B.; Hartman, H.; Hicks, E.; Mansot, J. L.; Cesaire, T.; Thomas, P.

    2008-12-01

    In order to investigate the effect of climate on soil and surface sediment properties we examined four transects around the Sahara Desert. The transects were located in Mali, Niger, Benin, Togo, Egypt and Morocco and, with the exception of Egypt, each crossed a significant climatological rainfall gradient. The Egyptian transect was designed to characterize one of the driest portions of the Sahara Desert. Our study included laboratory measurements of mineralogy (XRD), elemental composition (XRF), grain size, optical reflectance (lab), magnetic susceptibility (MS)and remanences. In addition, albedo was determined from the MODIS satellite imagery from space. Many of our laboratory measurements exhibited variations with the rainfall gradient. Iron oxides (hematite and goethite), kaolinite, Al2O3, and TiO2 increased with increasing rainfall whereas SiO2, illite, and grain size decreased with increasing rainfall. Both laboratory-determined reflectivity and satellite-determine albedo decreased as rainfall increased. In part, this decrease in reflectivity/albedo with increasing rainfall appears to be the result of hematite, the dominant coloring agent for the soil in this region and the origin of the 'red' Sahel. The physical interpretation of these results centers on rainfall as a long-term leaching agent of surface material, and the control of physical properties by specific mineralogy. SiO2 is highly reflective and iron oxides are strongly absorptive in the visible range. The solubility of SiO2 in rainwater is orders of magnitude larger than all the iron oxides, with hematite the least soluble. It has long been recognized that leaching by rainfall produces dark red laterite in the near-surface oxidizing environment, a prominent geological feature throughout the high rainfall belt of West Africa. Laterite beds represent simultaneous enrichments of all iron oxides and a reduction in SiO2 by leaching. In the Sahara desert where rainfall is minimal (<10 mm/yr), SiO2 is

  17. The spectrum of cancers in West Africa: associations with human immunodeficiency virus.

    Directory of Open Access Journals (Sweden)

    Aristophane Tanon

    Full Text Available BACKGROUND: Cancer is a growing co-morbidity among HIV-infected patients worldwide. With the scale-up of antiretroviral therapy (ART in developing countries, cancer will contribute more and more to the HIV/AIDS disease burden. Our objective was to estimate the association between HIV infection and selected types of cancers among patients hospitalized for diagnosis or treatment of cancer in West Africa. METHODS: A case-referent study was conducted in referral hospitals in Côte d'Ivoire and Benin. Each participating clinical ward enrolled all adult patients seeking care for a confirmed diagnosis of cancer and clinicians systematically proposed an HIV test. HIV prevalence was compared between AIDS-defining cancers and a subset of selected non-AIDS defining cancers to a referent group of non-AIDS defining cancers not reported in the literature to be positively or inversely associated with HIV. An unconditional logistic model was used to estimate odds ratios (OR and their 95% confidence intervals (CI of the risk of being HIV-infected for selected cancers sites compared to a referent group of other cancers. RESULTS: The HIV overall prevalence was 12.3% (CI 10.3-14.4 among the 1,017 cancer cases included. A total of 442 patients constituted the referent group with an HIV prevalence of 4.7% (CI 2.8-6.7. In multivariate analysis, Kaposi sarcoma (OR 62.2 [CI 22.1-175.5], non-Hodgkin lymphoma (4.0 [CI 2.0-8.0], cervical cancer (OR 7.9 [CI 3.8-16.7], anogenital cancer (OR 11.6 [CI 2.9-46.3] and liver cancer (OR 2.7 [CI 1.1-7.7] were all associated with HIV infection. CONCLUSIONS: In a time of expanding access to ART, AIDS-defining cancers remain highly associated with HIV infection. This is to our knowledge, the first study reporting a significant association between HIV infection and liver cancer in sub-Saharan Africa.

  18. Water balance estimation with the Budyko method to assess the hydropower potential of rivers in West Africa

    Science.gov (United States)

    Kling, Harald; Stanzel, Philipp; Fuchs, Martin

    2015-04-01

    Small and medium hydropower has a large potential for future development in West Africa, a region that is facing a constant shortage of energy supply and thereby limiting economic growth. The river reaches suitable for small and medium hydropower development are usually located in headwater areas. Mean annual discharge (along with slope) is a key variable for assessing the hydropower potential of a river reach. As discharge gauges are typically located at larger, downstream rivers a regionalization of flow is required. In this study we use the Budyko method to establish the spatially distributed mean annual water balance for whole West Africa (appr. 5 Mio km²), including the basins of e.g. Niger, Volta, and Senegal rivers. The spatially distributed inputs of mean annual precipitation and potential evapotranspiration are used to compute actual evapotranspiration and thus runoff. Runoff is aggregated along the river network to compute discharge. Due to the impact of different soils and vegetation cover the Budyko curve is calibrated with observed discharge data of about 100 basins covering a wide range of humid to semi-arid conditions. A framework is developed to properly account for the distinctive decadal variations of rainfall (and discharge) in West Africa. Specific challenges are (a) apparently biased discharge measurements at some gauges and (b) uncertainties in the precipitation data (station-based and satellite-based). The results of this study will give (1) an overview about the hydropower potential in each West African country and (2) the theoretical hydropower potential of about 100,000 river reaches. The results will be published on a website with interactive maps to enable the selection of regions of interest for further, detailed assessment of small and medium hydropower development.

  19. Factors affecting livestock predation by lions in Cameroon

    NARCIS (Netherlands)

    Bommel, van L.; Vaate, bij de M.D.; Boer, de W.F.; Iongh, de H.H.

    2007-01-01

    Interviews were carried out in six villages south-west of Waza National Park, Cameroon, to investigate the impact of factors related to the occurrence of livestock raiding by lions. Data were analysed at the village and individual level. Livestock losses (cattle, sheep and/or goats) caused by lions

  20. Validating modeled soil moisture with in-situ data for agricultural drought monitoring in West Africa

    Science.gov (United States)

    McNally, A.; Yatheendradas, S.; Jayanthi, H.; Funk, C. C.; Peters-Lidard, C. D.

    2011-12-01

    The declaration of famine in Somalia on July 21, 2011 highlights the need for regional hydroclimate analysis at a scale that is relevant for agropastoral drought monitoring. A particularly critical and robust component of such a drought monitoring system is a land surface model (LSM). We are currently enhancing the Famine Early Warning Systems Network (FEWS NET) monitoring activities by configuring a custom instance of NASA's Land Information System (LIS) called the FEWS NET Land Data Assimilation System (FLDAS). Using the LIS Noah LSM, in-situ measurements, and remotely sensed data, we focus on the following question: How can Noah be best parameterized to accurately simulate hydroclimate variables associated with crop performance? Parameter value testing and validation is done by comparing modeled soil moisture against fortuitously available in-situ soil moisture observations in the West Africa. Direct testing and application of the FLDAS over African agropastoral locations is subject to some issues: [1] In many regions that are vulnerable to food insecurity ground based measurements of precipitation, evapotranspiration and soil moisture are sparse or non-existent, [2] standard landcover classes (e.g., the University of Maryland 5 km dataset), do not include representations of specific agricultural crops with relevant parameter values, and phenologies representing their growth stages from the planting date and [3] physically based land surface models and remote sensing rain data might still need to be calibrated or bias-corrected for the regions of interest. This research aims to address these issues by focusing on sites in the West African countries of Mali, Niger, and Benin where in-situ rainfall and soil moisture measurements are available from the African Monsoon Multidisciplinary Analysis (AMMA). Preliminary results from model experiments over Southern Malawi, validated with Normalized Difference Vegetation Index (NDVI) and maize yield data, show that the

  1. Assessments for the impact of mineral dust on the meningitis incidence in West Africa

    Science.gov (United States)

    Martiny, Nadège; Chiapello, Isabelle

    2013-05-01

    Recently, mineral dust has been suspected to be one of the important environmental risk factor for meningitis epidemics in West Africa. The current study is one of the first which relies on long-term robust aerosol measurements in the Sahel region to investigate the possible impact of mineral dust on meningitis cases (incidence). Sunphotometer measurements, which allow to derive aerosol and humidity parameters, i.e., aerosol optical thickness, Angström coefficient, and precipitable water, are combined with quantitative epidemiological data in Niger and Mali over the 2004-2009 AMMA (African Monsoon Multidisciplinary Analysis) program period. We analyse how the extremely high aerosol loads in this region may influence both the calendar (onset, peaks, end) and the intensity of meningitis. We highlight three distinct periods: (i) from November to December, beginning of the dry season, humidity is weak, there is no dust and no meningitis cases; (ii) from January to April, humidity is still weak, but high dust loads occur in the atmosphere and this is the meningitis season; (iii) from May to October, humidity is high and there is no meningitis anymore, in presence of dust or not, which flow anyway in higher altitudes. More specifically, the onset of the meningitis season is tightly related to mineral dust flowing close to the surface at the very beginning of the year. During the dry, and the most dusty season period, from February to April, each meningitis peak is preceded by a dust peak, with a 0-2 week lead-time. The importance (duration, intensity) of these meningitis peaks seems to be related to that of dust, suggesting that a cumulative effect in dust events may be important for the meningitis incidence. This is not the case for humidity, confirming the special contribution of dust at this period of the year. The end of the meningitis season, in May, coincides with a change in humidity conditions related to the West African Monsoon. These results, which are

  2. Raptors in changing West African savannas : the impact of anthropogenic land transformation on populations of Palearctic and Afrotropical raptors in northern Cameroon

    NARCIS (Netherlands)

    Buij, Ralph

    2013-01-01

    Raptors in West Africa’s savannas have strongly declined the past four decades and many species now survive only in a few pockets of intact habitat, mostly inside protected areas, while some species are on the brink of extinction. Little is known about the processes that sustain raptor populations w

  3. Parameter identification of the SWAT model on the BANI catchment (West Africa) under limited data condition

    Science.gov (United States)

    Chaibou Begou, Jamilatou; Jomaa, Seifeddine; Benabdallah, Sihem; Rode, Michael

    2015-04-01

    Due to the climate change, drier conditions have prevailed in West Africa, since the seventies, and the consequences are important on water resources. In order to identify and implement management strategies of adaptation to climate change in the sector of water, it is crucial to improve our physical understanding of water resources evolution in the region. To this end, hydrologic modelling is an appropriate tool for flow predictions under changing climate and land use conditions. In this study, the applicability and performance of the recent version of Soil and Water Assessment Tool (SWAT2012) model were tested on the Bani catchment in West Africa under limited data condition. Model parameters identification was also tested using one site and multisite calibration approaches. The Bani is located in the upper part of the Niger River and drains an area of about 101, 000 km2 at the outlet of Douna. The climate is tropical, humid to semi-arid from the South to the North with an average annual rainfall of 1050 mm (period 1981-2000). Global datasets were used for the model setup such as: USGS hydrosheds DEM, USGS LCI GlobCov2009 and the FAO Digital Soil Map of the World. Daily measured rainfall from nine rain gauges and maximum and minimum temperature from five weather stations covering the period 1981-1997 were used for model setup. Sensitivity analysis, calibration and validation are performed within SWATCUP using GLUE procedure at Douna station first (one site calibration), then at three additional internal stations, Bougouni, Pankourou and Kouoro1 (multi-site calibration). Model parameters were calibrated at daily time step for the period 1983-1992, then validated for the period 1993-1997. A period of two years (1981-1982) was used for model warming up. Results of one-site calibration showed that the model performance is evaluated by 0.76 and 0.79 for Nash-Sutcliffe (NS) and correlation coefficient (R2), respectively. While for the validation period the performance

  4. Partnership research on nutrition transition and chronic diseases in West Africa – trends, outcomes and impacts

    Directory of Open Access Journals (Sweden)

    Fayomi Benjamin

    2011-11-01

    Full Text Available Abstract Background Nutrition-related chronic diseases (NRCD are rising quickly in developing countries, and the nutrition transition is a major contributor. Low-income countries have not been spared. Health issues related to nutritional deficiencies also persist, creating a double burden of malnutrition (DBM. There is still a major shortage of data on NRCD and DBM in Sub-Saharan Africa. A research program has been designed and conducted in partnership with West African institutions since 2003 to determine how the nutrition transition relates to NRCD and the DBM in order to support prevention efforts. Methods In Benin, cross-sectional studies among apparently healthy adults (n=540 from urban, semi-urban and rural areas have examined cardiometabolic risk (hypertension, obesity, dyslipidemia, insulin resistance in relation to diet and lifestyle, also factoring in socio-economic status (SES. Those studies were followed by a longitudinal study on how risk evolves, opening the way for mutual aid groups to develop a prevention strategy within an action research framework. In Burkina Faso, a cross-sectional study on the nutritional status and dietary patterns of urban school-age children (n=650 represented the initial stages of an action research project to prevent DBM in schools. A cross-sectional study among adults (n=330 from the capital of Burkina Faso explored the coexistence, within these individuals, of cardiometabolic risk factors and nutritional deficiencies (anemia, vitamin A deficiency, chronic energy deficiency, as they relate to diet, lifestyle and SES. Results The studies have shown that the prevalence of NRCD is high among the poor, thereby exacerbating social inequalities. The hypothesis of a positive socio-economic (and rural–urban gradient was confirmed only for obesity, whereas the prevalence of hypertension, insulin resistance and dyslipidemia did not prove to be higher among affluent city dwellers. Women were particularly

  5. Dictating participation? Rethinking the adaptive co-management of socio-ecological systems in West Africa

    Science.gov (United States)

    El Vilaly, Audra; Abd salam El Vilaly, Mohamed

    2015-04-01

    In the face of environmental change, enhancing adaptive capacity relies on stakeholder engagement. But the participatory process, while critical to the translation, transfer, and application of scientific knowledge to society, is not without its own contradictions. These include the asymmetrical relations of power that prevail between environmental scientists, managers, and local users; discrepant understandings of knowledge and its appropriate uses; and conflicting social, economic, and ecological values, to name only a few. Our research examines five major transboundary river basin organizations in West Africa and their efforts to improve adaptive basin management via stakeholder collaboration. In particular, we evaluate the participatory strategies of these organizations to measure non-linear, multi-directional feedbacks between the social and biophysical factors of land use/land cover change, as well as the impacts of this change on basins and their dependent populations. Our research suggests that oftentimes, these methods paradoxically produce a hierarchical and marginalizing effect on local stakeholders in relation to the scientists that study them. In seeking to address these limitations, we assess the potential costs and benefits of integrating select components of a Participatory Action Research (PAR) framework (see, for example, Reason & Bradbury-Huang, 2007) into studies of complex socio-ecological problems. This approach, used widely in the social sciences, promotes critical reflection on and minimization of the power inequities inherent in science-society collaborations. It instead favors more horizontal forms of knowledge co-production that support and foster the expansion of local, existing movements for social and environmental justice. A PAR framework may therefore improve the efficiency, sustainability, and equitability of land-based adaptation to environmental change; further research is thus recommended to test this hypothesis. References

  6. Improving Hydro-Climatic Projections with Bias-Correction in Sahelian Niger Basin, West Africa

    Directory of Open Access Journals (Sweden)

    Ganiyu Titilope Oyerinde

    2017-02-01

    Full Text Available Climate simulations in West Africa have been attributed with large uncertainties. Global climate projections are not consistent with changes in observations at the regional or local level of the Niger basin, making management of hydrological projects in the basin uncertain. This study evaluates the potential of using the quantile mapping bias correction to improve the Coupled Model Intercomparison Project (CMIP5 outputs for use in hydrological impact studies. Rainfall and temperature projections from 8 CMIP5 Global Climate Models (GCM were bias corrected using the quantile mapping approach. Impacts of climate change was evaluated with bias corrected rainfall, temperature and potential evapotranspiration (PET. The IHACRES hydrological model was adapted to the Niger basin and used to simulate impacts of climate change on discharge under present and future conditions. Bias correction with quantile mapping significantly improved the accuracy of rainfall and temperature simulations compared to observations. The mean of six efficiency coefficients used for monthly rainfall comparisons of 8 GCMs to the observed ranged from 0.69 to 0.91 and 0.84 to 0.96 before and after bias correction, respectively. The range of the standard deviations of the efficiency coefficients among the 8 GCMs rainfall data were significantly reduced from 0.05–0.14 (before bias correction to 0.01–0.03 (after bias correction. Increasing annual rainfall, temperature, PET and river discharge were projected for most of the GCMs used in this study under the RCP4.5 and RCP8.5 scenarios. These results will help improving projections and contribute to the development of sustainable climate change adaptation strategies.

  7. Studies of 21st-Century Precipitation Trends Over West Africa

    Science.gov (United States)

    Druyan, Leonard M.

    2010-01-01

    West Africa includes a semi-arid zone between the Sahara Desert and the humid Gulf of Guinea coast, approximately between 10 N and 20 N, which is irrigated by summer monsoon rains. This article refers to the region as the Sahel. Rain-fed agriculture is the primary sustenance for Sahel populations, and severe droughts (in the 1970s and 1980s), therefore, have devastating negative societal impacts. The future frequency of Sahel droughts and the evolution of its hydrological balance are therefore of great interest. The article reviews 10 recent research studies that attempt to discover how climate changes will affect the hydrology of the Sahel throughout the 21st century. All 10 studies rely on atmosphere ocean global climate model (AOGCM) simulations based on a range of greenhouse gas emissions scenarios. Many of the simulations are contained in the Intergovernmental Panel on Climate Change archives for Assessment Reports #3 and #4. Two of the studies use AOGCM data to drive regional climate models. Seven studies make projections for the first half of the 21st century and eight studies make projections for the second half. Some studies make projections of wetter conditions and some predict more frequent droughts, and each describes the atmospheric processes associated with its prediction. Only one study projects more frequent droughts before 2050, and that is only for continent-wide degradation in vegetation cover. The challenge to correctly simulate Sahel rainfall decadal trends is particularly daunting because multiple physical mechanisms compete to drive the trend upwards or downwards. A variety of model deficiencies, regarding the simulation of one or more of these physical processes, taints models climate change projections. Consequently, no consensus emerges regarding the impact of anticipated greenhouse gas forcing on the hydrology of the Sahel in the second half of the 21st century.

  8. The Impact of the West Africa Ebola Outbreak on Obstetric Health Care in Sierra Leone.

    Directory of Open Access Journals (Sweden)

    Kim J Brolin Ribacke

    Full Text Available As Sierra Leone celebrates the end of the Ebola Virus Disease (EVD outbreak, we can begin to fully grasp its impact on already weak health systems. The EVD outbreak in West Africa forced many hospitals to close down or reduce their activity, either to prevent nosocomial transmission or because of staff shortages. The aim of this study is to assess the potential impact of EVD on nationwide access to obstetric care in Sierra Leone.Community health officers collected weekly data between January 2014-May 2015 on in-hospital deliveries and caesarean sections (C-sections from all open facilities (public, private for-profit and private non-profit sectors offering emergency obstetrics in Sierra Leone. This was compared to official data of EVD cases per district. Logistic and Poisson regression analyses were used to compute risk and rate estimates. Nationwide, the number of in-hospital deliveries and C-sections decreased by over 20% during the EVD outbreak. The decline occurred early on in the EVD outbreak and was mainly attributable to the closing of private not-for-profit hospitals rather than government facilities. Due to difficulties in collecting data in the midst of an epidemic, limitations of this study include some missing data points.Both the number of in-hospital deliveries and C-sections substantially declined shortly after the onset of the EVD outbreak. Since access to emergency obstetric care, like C-sections, is associated with decreased maternal mortality, many women are likely to have died due to the reduced access to appropriate care during childbirth. Future research on indirect health effects of health system breakdown should ideally be nationwide and continue also into the recovery phase. It is also important to understand the mechanisms behind the deterioration so that important health services can be reestablished.

  9. Calculating crop water requirement satisfaction in the West Africa Sahel with remotely sensed soil moisture

    Science.gov (United States)

    McNally, Amy; Gregory J. Husak,; Molly Brown,; Mark Carroll,; Funk, Christopher C.; Soni Yatheendradas,; Kristi Arsenault,; Christa Peters-Lidard,; Verdin, James

    2015-01-01

    The Soil Moisture Active Passive (SMAP) mission will provide soil moisture data with unprecedented accuracy, resolution, and coverage, enabling models to better track agricultural drought and estimate yields. In turn, this information can be used to shape policy related to food and water from commodity markets to humanitarian relief efforts. New data alone, however, do not translate to improvements in drought and yield forecasts. New tools will be needed to transform SMAP data into agriculturally meaningful products. The objective of this study is to evaluate the possibility and efficiency of replacing the rainfall-derived soil moisture component of a crop water stress index with SMAP data. The approach is demonstrated with 0.1°-resolution, ~10-day microwave soil moisture from the European Space Agency and simulated soil moisture from the Famine Early Warning Systems Network Land Data Assimilation System. Over a West Africa domain, the approach is evaluated by comparing the different soil moisture estimates and their resulting Water Requirement Satisfaction Index values from 2000 to 2010. This study highlights how the ensemble of indices performs during wet versus dry years, over different land-cover types, and the correlation with national-level millet yields. The new approach is a feasible and useful way to quantitatively assess how satellite-derived rainfall and soil moisture track agricultural water deficits. Given the importance of soil moisture in many applications, ranging from agriculture to public health to fire, this study should inspire other modeling communities to reformulate existing tools to take advantage of SMAP data.

  10. Bladder Cancer Screening Among Diabetic Patients On Metformin Therapy In A West Africa Subregion

    Directory of Open Access Journals (Sweden)

    Ufuoma Miller Fakpor

    2016-10-01

    Full Text Available Objective: The use of certain medications among diabetic patients put them at risk of developing bladder cancer. This study was done to examine the effects of metformin therapy on the bladder of diabetic patients and to assess the correlation between the effects of metformin and its duration of therapy. Methods: A total of 150 diabetic patients were sampled using a cross sectional study design. 10-15mls of random urine samples were collected into sterile containers over a period of five weeks. Smears were prepared, fixed and stained using Papanicolaou staining method and examined under the microscope for cytological studies. Results: The probability of developing bladder cancer among diabetic patients on metformin therapy is 0% among participants of all categories: 99 females and 51 males partook in this study.  Peak age group (35.33% were between the ages of 51 to 60 years, least age group (4.67% were 80 years and above. Traders of food items and used clothes constituted the peak occupational group of 27.52%, with fishermen  as least occupation group(0.67%, age group 61 to 70 had the highest duration of therapy of (15.8%, the least duration of (4.625% was among age group 25 to 30 years, the group of 80years and above had a duration of (4.857%.  No inflammatory, degenerative, benign or malignant cells were observed among urine samples from diabetic patients on metformin. Conclusion: This study equips us with knowledge that metformin therapy has no direct influence on the development of cancer of the bladder among diabetic patients as observed through urine cytology. This is the first time such study is done in West Africa region. The clinical implication is that Metformin, the commonest prescribed oral hypoglycemic is safe when considering the carcinogenic effects of anti-diabetic drugs, unlike insulin and some other drugs which have carcinogenic potential.   Keywords: metformin; cancer; bladder; diabetes; therapy

  11. Overview of main challenges for Early Warning Systems for Food Security in West Africa

    Science.gov (United States)

    Genesio, Lorenzo; Bacci, Maurizio; Baron, Christian; Diarra, Birama; di Vecchia, Andrea; Traoré, Seydou; Hassane, Idrissa; Ndiaye, Mamadou; Philippon, Nathalie; Tarchiani, Vieri

    2010-05-01

    In West Africa Early Warning Systems (EWSs) for food security have been widely recognized to have contributed in the last twenty years to better face famine emergencies. The improved understanding of the environmental and socio-economic dynamics of the region, a change in the causes for food insecurity and the evolution of Information and Communication Technologies (ICT) have favored the introduction of new approaches and the involvement of a network of stakeholders. In recent years the improvement of EWS has been concentrated in the adaptation and the transfer of existing tools rather than the development of the overall design of EWS in function of users needs, at the same time key scientific areas to be improved to provide major operational advancements needs to be better identified. This partially due to a difficulty of the research community to be in direct connection with operational processes and on the other side by an evident limit in following a demand driven approach due to the difficulties in modelling bio and social phenomena in a unique environment. In this context AMMA project had the ambitious objective of bridging the gap between state of the art research in the domains of geo-science and human related disciplines, and the operational EWS. The work carried out in AMMA, while improving the understanding of monsoon system, allowed to better orient research challenges in order to provide EWS with improved products effectively meeting the needs of end-users at different levels. In this work, advancements in providing appropriate information for the identification of agricultural risk zones by using short to long time forecasts are illustrated highlighting critical aspects still demanding scientific improvements.

  12. Cultural valuation and biodiversity conservation in the Upper Guinea forest, West Africa

    Directory of Open Access Journals (Sweden)

    James A. Fraser

    2016-09-01

    Full Text Available The cultural valuation of biodiversity has taken on renewed importance over the last two decades as the ecosystem services framework has become widely adopted. Conservation initiatives increasingly use ecosystem service frameworks to render tropical forest landscapes and their peoples legible to market-oriented initiatives such as REDD+ and biodiversity offsetting schemes. Ecosystem service approaches have been widely criticized by scholars in the social sciences and humanities for their narrow focus on a small number of easily quantifiable and marketable services and a reductionist and sometimes simplistic approach to culture. We address the need to combine methods from each of the "three cultures" of natural science, quantitative social science, and qualitative social science/humanities in conceptualizing the relationship between cultural valuation and biodiversity conservation. We combine qualitative data with forest inventories and a quantitative index of cultural value to evaluate the relationship between cultural valuation and biodiversity conservation in Upper Guinea forest in Liberia, West Africa. Our study focuses on "sacred agroforests," spaces that are associated with Mande macro-language speaking groups such as the Loma. We demonstrate that sacred agroforests are associated with different cultural values compared with secondary forests. Although biodiversity and biomass are similar, sacred agroforests exhibit a different species composition, especially of culturally salient species, increasing overall landscape agro-biodiversity. Sacred agroforests are also shaped and conserved by local cultural institutions revolving around ancestor worship, ritual, and the metaphysical conceptual category "salɛ." We conclude that to understand the relationship between cultural valuation and biodiversity conservation, interpretivist approaches such as phenomenology should be employed alongside positivist ecosystem service frameworks.

  13. Ecosystem properties of semiarid savanna grassland in West Africa and its relationship with environmental variability.

    Science.gov (United States)

    Tagesson, Torbern; Fensholt, Rasmus; Guiro, Idrissa; Rasmussen, Mads Olander; Huber, Silvia; Mbow, Cheikh; Garcia, Monica; Horion, Stéphanie; Sandholt, Inge; Holm-Rasmussen, Bo; Göttsche, Frank M; Ridler, Marc-Etienne; Olén, Niklas; Lundegard Olsen, Jørgen; Ehammer, Andrea; Madsen, Mathias; Olesen, Folke S; Ardö, Jonas

    2015-01-01

    The Dahra field site in Senegal, West Africa, was established in 2002 to monitor ecosystem properties of semiarid savanna grassland and their responses to climatic and environmental change. This article describes the environment and the ecosystem properties of the site using a unique set of in situ data. The studied variables include hydroclimatic variables, species composition, albedo, normalized difference vegetation index (NDVI), hyperspectral characteristics (350-1800 nm), surface reflectance anisotropy, brightness temperature, fraction of absorbed photosynthetic active radiation (FAPAR), biomass, vegetation water content, and land-atmosphere exchanges of carbon (NEE) and energy. The Dahra field site experiences a typical Sahelian climate and is covered by coexisting trees (~3% canopy cover) and grass species, characterizing large parts of the Sahel. This makes the site suitable for investigating relationships between ecosystem properties and hydroclimatic variables for semiarid savanna ecosystems of the region. There were strong interannual, seasonal and diurnal dynamics in NEE, with high values of ~-7.5 g C m(-2)  day(-1) during the peak of the growing season. We found neither browning nor greening NDVI trends from 2002 to 2012. Interannual variation in species composition was strongly related to rainfall distribution. NDVI and FAPAR were strongly related to species composition, especially for years dominated by the species Zornia glochidiata. This influence was not observed in interannual variation in biomass and vegetation productivity, thus challenging dryland productivity models based on remote sensing. Surface reflectance anisotropy (350-1800 nm) at the peak of the growing season varied strongly depending on wavelength and viewing angle thereby having implications for the design of remotely sensed spectral vegetation indices covering different wavelength regions. The presented time series of in situ data have great potential for dryland dynamics

  14. Participatory planning in river catchments, an innovative toolkit tested in Southern Africa and North West England.

    Science.gov (United States)

    Tippett, J

    2005-01-01

    The European Union Water Framework Directive (WFD) offers an unparalleled opportunity for improving river basin management. Active participation is essential for its delivery. "End-of-pipe" solutions will not deliver the improvements needed to achieve its ambitious goals. This research tested DesignWays, a toolkit for participatory planning, as a mechanism for maximizing the long-term social and environmental benefits of such stakeholder and community participation. It examined the emerging role of "planning for sustainability" in the context of river catchments. Sustainable management of water requires integration, and recognition of interconnections between systems at different levels of scale. This is an endeavour in which systems thinking provides useful tools. The development of DesignWays was a conscious attempt to embed 'new paradigm' living systems metaphors into a practical planning tool. This paper begins with a description of DesignWays and its development in Southern Africa. An outline of the context of the action research in North-West England is followed by a description of the stages of the process, with highlights of the outcomes. This research had two major outcomes: a contribution to theory through an in-depth exploration of the theoretical basis of participatory, ecologically informed design; and a contribution to practice through investigating DesignWays' potential to meet key challenges of the WFD. This research points to the importance of understanding participatory planning as a societal process, aiming to make the process engaging and meaningful. It has pointed to the need to see participatory planning and education for sustainability as an integrated process. It demonstrated the benefits of an iterative process in which planning at the landscape level of scale informs, and is informed by, work at the site level. It has shown that an approach consistent with a living systems paradigm can contribute to the development of more integrated

  15. Optimal feeding systems for small-scale dairy herds in the North West Province, South Africa

    Directory of Open Access Journals (Sweden)

    N. Patience Manzana

    2014-02-01

    Full Text Available Land redistribution was legislated in 1994; it was designed to resolve historical imbalances inland ownership in South Africa. Between 2002 and 2006, a longitudinal observational studywas conducted with 15 purposively selected small-scale dairy farmers in a land redistributionproject in Central North West Province. Four farmers left the project over the period. For thepurposes of this study, a small-scale dairy farm was defined as a farm that produces less than500 L of milk a day, irrespective of the number of cows or size of the farm. The study wasconducted in three phases. In the first phase, situational analysis using participatory ruralappraisal (PRA and observation was used to outline the extent of the constraints and designappropriate interventions. Feeds that were used were tested and evaluated. In the secondphase, three different feeding systems were designed from the data obtained from PRA. Thesewere: (1 A semi-intensive farm-based ration using available crops, pastures and crop residueswith minimal rations purchased. (2 An intensive, zero-grazing dairy system using a totalmixed ration. (3 A traditional, extensive or dual-purpose system, where the calf drank fromthe cow until weaning and milking was done only once a day. In the third phase, adoptionwas monitored. By July 2006, all remaining farmers had changed to commercially formulatedrations or licks and the body condition score of the cows had improved. It was concluded thatveterinary extension based on PRA and a holistic systems approach was a good option forsuch complex problems. Mentoring by commercial dairy farmers, veterinary and extensionservices appeared to be viable. Further research should be done to optimise the traditionalmodel of dairy farming, as this was relatively profitable, had a lower risk and was less labourintensive.

  16. Optimal feeding systems for small-scale dairy herds in the North West Province, South Africa.

    Science.gov (United States)

    Manzana, N Patience; McCrindle, Cheryl M E; Sebei, P Julius; Prozesky, Leon

    2014-07-09

    Land redistribution was legislated in 1994; it was designed to resolve historical imbalances inland ownership in South Africa. Between 2002 and 2006, a longitudinal observational studywas conducted with 15 purposively selected small-scale dairy farmers in a land redistributionproject in Central North West Province. Four farmers left the project over the period. For thepurposes of this study, a small-scale dairy farm was defined as a farm that produces less than500 L of milk a day, irrespective of the number of cows or size of the farm. The study wasconducted in three phases. In the first phase, situational analysis using participatory ruralappraisal (PRA) and observation was used to outline the extent of the constraints and designappropriate interventions. Feeds that were used were tested and evaluated. In the secondphase, three different feeding systems were designed from the data obtained from PRA. Thesewere: (1) A semi-intensive farm-based ration using available crops, pastures and crop residueswith minimal rations purchased. (2) An intensive, zero-grazing dairy system using a totalmixed ration. (3) A traditional, extensive or dual-purpose system, where the calf drank fromthe cow until weaning and milking was done only once a day. In the third phase, adoptionwas monitored. By July 2006, all remaining farmers had changed to commercially formulatedrations or licks and the body condition score of the cows had improved. It was concluded thatveterinary extension based on PRA and a holistic systems approach was a good option forsuch complex problems. Mentoring by commercial dairy farmers, veterinary and extensionservices appeared to be viable. Further research should be done to optimise the traditionalmodel of dairy farming, as this was relatively profitable, had a lower risk and was less labourintensive.

  17. Ebola or Not? Evaluating the Ill Traveler From Ebola-Affected Countries in West Africa.

    Science.gov (United States)

    Fairley, Jessica K; Kozarsky, Phyllis E; Kraft, Colleen S; Guarner, Jeannette; Steinberg, James P; Anderson, Evan; Jacob, Jesse T; Meloy, Patrick; Gillespie, Darria; Espinoza, Tamara R; Isakov, Alexander; Vanairsdale, Sharon; Baker, Esther; Wu, Henry M

    2016-01-01

    Background.  The 2014-2015 Ebola epidemic in West Africa had global impact beyond the primarily affected countries of Guinea, Liberia, and Sierra Leone. Other countries, including the United States, encountered numerous patients who arrived from highly affected countries with fever or other signs or symptoms consistent with Ebola virus disease (EVD). Methods.  We describe our experience evaluating 25 travelers who met the US Centers for Disease Control and Prevention case definition for a person under investigation (PUI) for EVD from July 20, 2014 to January 28, 2015. All patients were triaged and evaluated under the guidance of institutional protocols to the emergency department, outpatient tropical medicine clinic, or Emory's Ebola treatment unit. Strict attention to infection control and early involvement of public health authorities guided the safe evaluation of these patients. Results.  None were diagnosed with EVD. Respiratory illnesses were common, and 8 (32%) PUI were confirmed to have influenza. Four patients (16%) were diagnosed with potentially life-threatening infections or conditions, including 3 with Plasmodium falciparum malaria and 1 with diabetic ketoacidosis. Conclusions.  In addition to preparing for potential patients with EVD, Ebola assessment centers should consider other life-threatening conditions requiring urgent treatment, and travelers to affected countries should be strongly advised to seek pretravel counseling. Furthermore, attention to infection control in all aspects of PUI evaluation is paramount and has presented unique challenges. Lessons learned from our evaluation of potential patients with EVD can help inform preparations for future outbreaks of highly pathogenic communicable diseases.

  18. Characteristics of Droughts in South Africa: A Case Study of Free State and North West Provinces

    Directory of Open Access Journals (Sweden)

    Christina M. Botai

    2016-10-01

    Full Text Available The Free State (FS and North West (NW Provinces are often hard hit by droughts with impacts on water availability, farm production and livestock holdings. The South African government declared the two Provinces drought disaster areas in the 2015/2016 hydrological year. This is a major drawback, since both the Provinces play an important role to South African economy as they are a haven to agricultural production and have major water reservoirs in South Africa. This study was undertaken to investigate the historical evolution of drought within the FS and NW Provinces over the past 30 years. The Standardized Precipitation Index (SPI and Standardized Precipitation Evapotranspiration Index (SPEI calculated based on monthly meteorological data from 14 weather/climate stations within the FS and NW Provinces were used to explore and characterize variation in drought intensity, duration, frequency and severity in FS and NW Provinces during 1985–2015. Results indicate that there exist localized positive and negative trends with spatial dependence across the selected stations. In particular, about 60% of the weather stations exhibiting a decreasing trend are located in FS Province, suggesting that FS has being experiencing increasing drought during the analyzed period compared to NW Province. Results from the analysis of drought evaluation indicators (DEIs calculated from SPEI suggest that drought severity and frequency was more pronounced in FS while the intensity of the drought was more in NW Province during 1985–2015. In addition, based on SPEI calculations, moderate drought occurrences increased during 1985–1994 and 1995–2004 periods and decreased thereafter (2005–2015 in both Provinces. Drought classification based on parameters derived from SPEI produced similar results for mild drought occurrences during the same time scales.

  19. 'FAN the SUN brighter': fortifying Africa nutritionally (FAN) - the role of public private partnership in scaling up nutrition (SUN) in West Africa.

    Science.gov (United States)

    Sablah, Mawuli; Baker, Shawn K; Badham, Jane; De Zayas, Alfred

    2013-11-01

    The scaling up nutrition (SUN) policy framework requires extensive public–private partnership (PPP). Malnutrition is multi-dimensional and should engage multi-sectoral platforms. The SUN policy however did not fully embrace the dynamics of harnessing PPP. The objectives of the present paper are to highlight the reasons for the apprehension around PPP and illustrate how effective coordination of PPP in West Africa has contributed to implementing large-scale food fortification with micronutrients as a complementary nutrition intervention. The experience of Helen Keller International (HKI) in scaling up food fortification was emphasised with understanding of the factors contributing to indifference by the international community to private sector contribution to SUN. The roles of different stakeholders in a PPP are elucidated and the process linked to who, why and how to engage. The private sector provides direct nutrition services while the public sector creates the enabling environment for the private sector to thrive on social values. Through this approach fortified vegetable oil and wheat flour are now reaching over 70% of the population in West Africa. As a neutral broker HKI coordinated and facilitated dialogue among the different stakeholders. The core competencies of each stakeholder were harnessed and each partner was held accountable. It concludes that multi-sectoral relationship must be transparent, equitable and based on shared mutual interests. The rules and values of PPP offer opportunities for SUN.

  20. The Foraging Ecology of the Endangered Cape Verde Shearwater, a Sentinel Species for Marine Conservation off West Africa.

    Directory of Open Access Journals (Sweden)

    Vitor H Paiva

    Full Text Available Large Marine Ecosystems such as the Canary Current system off West Africa sustains high abundance of small pelagic prey, which attracts marine predators. Seabirds are top predators often used as biodiversity surrogates and sentinel species of the marine ecosystem health, thus frequently informing marine conservation planning. This study presents the first data on the spatial (GPS-loggers and trophic (stable isotope analysis ecology of a tropical seabird-the endangered Cape Verde shearwater Calonectris edwardsii-during both the incubation and the chick-rearing periods of two consecutive years. This information was related with marine environmental predictors (species distribution models, existent areas of conservation concern for seabirds (i.e. marine Important Bird Areas; marine IBAs and threats to the marine environment in the West African areas heavily used by the shearwaters. There was an apparent inter-annual consistency on the spatial, foraging and trophic ecology of Cape Verde shearwater, but a strong alteration on the foraging strategies of adult breeders among breeding phases (i.e. from incubation to chick-rearing. During incubation, birds mostly targeted a discrete region off West Africa, known by its enhanced productivity profile and thus also highly exploited by international industrial fishery fleets. When chick-rearing, adults exploited the comparatively less productive tropical environment within the islands of Cape Verde, at relatively close distance from their breeding colony. The species enlarged its trophic niche and increased the trophic level of their prey from incubation to chick-rearing, likely to provision their chicks with a more diversified and better quality diet. There was a high overlap between the Cape Verde shearwaters foraging areas with those of European shearwater species that overwinter in this area and known areas of megafauna bycatch off West Africa, but very little overlap with existing Marine Important Bird

  1. The Foraging Ecology of the Endangered Cape Verde Shearwater, a Sentinel Species for Marine Conservation off West Africa.

    Science.gov (United States)

    Paiva, Vitor H; Geraldes, Pedro; Rodrigues, Isabel; Melo, Tommy; Melo, José; Ramos, Jaime A

    2015-01-01

    Large Marine Ecosystems such as the Canary Current system off West Africa sustains high abundance of small pelagic prey, which attracts marine predators. Seabirds are top predators often used as biodiversity surrogates and sentinel species of the marine ecosystem health, thus frequently informing marine conservation planning. This study presents the first data on the spatial (GPS-loggers) and trophic (stable isotope analysis) ecology of a tropical seabird-the endangered Cape Verde shearwater Calonectris edwardsii-during both the incubation and the chick-rearing periods of two consecutive years. This information was related with marine environmental predictors (species distribution models), existent areas of conservation concern for seabirds (i.e. marine Important Bird Areas; marine IBAs) and threats to the marine environment in the West African areas heavily used by the shearwaters. There was an apparent inter-annual consistency on the spatial, foraging and trophic ecology of Cape Verde shearwater, but a strong alteration on the foraging strategies of adult breeders among breeding phases (i.e. from incubation to chick-rearing). During incubation, birds mostly targeted a discrete region off West Africa, known by its enhanced productivity profile and thus also highly exploited by international industrial fishery fleets. When chick-rearing, adults exploited the comparatively less productive tropical environment within the islands of Cape Verde, at relatively close distance from their breeding colony. The species enlarged its trophic niche and increased the trophic level of their prey from incubation to chick-rearing, likely to provision their chicks with a more diversified and better quality diet. There was a high overlap between the Cape Verde shearwaters foraging areas with those of European shearwater species that overwinter in this area and known areas of megafauna bycatch off West Africa, but very little overlap with existing Marine Important Bird Areas. Further

  2. Projected changes in daily precipitation in West Africa with implications for crop production around 2050 in CORDEX simulations

    Science.gov (United States)

    Wisser, Dominik; Müller, Marc; Bamba Sylla, Mouhamadou; Ibrahim, Boubacar; Henning Sommer, Jan

    2015-04-01

    With irrigation occupying less than 1% of all croplands, agricultural production in West Africa can potentially severely impacted by changes in precipitation. We identified a number of precipitation characteristics that impact crop yields and analyze mid 21st century changes in these characteristics over croplands in West Africa using a multi model ensemble of 16 RCM/GCM combinations providing data for the CORDEX Africa domain. Besides long term mean values, we analyze interannual variability of these precipitation characteristics. Despite a moderate increase (~3%) in total rainy season precipitation in the ensemble mean prediction, we find other characteristics that could potentially have detrimental effects on crop yields. A robust and consistent delay in the onset of the rainy season (1 to 4 days from South to North), with no apparent change in the cessation of the rainy season, leads to a general shortening of the rainy season. Rainfall intensity generally increases with a slight decrease in the number of rainy days (> 5mm) during the rainy season. No noticeable change was found in the dry spell frequency (5-15 days). These changes do not only impact agricultural production but can have wide ranging effects on other sectors. The spatial consistency of these changes highlight the need for regional prioritization of adaptation measures such as an expansion of irrigated areas.

  3. Seismic architecture and morphology of Neogenic sediment waves and drifts, offshore West Africa

    Science.gov (United States)

    Baglioni, Luca; Bonamini, Enrico

    2013-04-01

    fill SW troughs. The positive relief of wave crests guided sediment gravity flows, inducing erosion and deposition focused along wave troughs. The shallower interval is fully dominated by bottom current deposits. A succession of SW around 300 ms thick covers the central-eastern sector of the study area. The described SW field is about 5 km wide and continuous over a distance of 30 km, and the average wavelength between two crests is 2 km. It is connected updip with a time equivalent rectilinear canyon-shaped erosive feature, whose genetic relation with the SW is now matter of discussion. The presence of upslope migrating SW indicates deposition by bottom current flowing upslope, under the influence of the Coriolis force. Such landwards-directed bottom currents on the slope probably represent the still active South-East Atlantic Upwelling, which has been present along the West Africa margin throughout the Neogene.

  4. The 2014 Ebola virus outbreak in West Africa highlights no evidence of rapid evolution or adaptation to humans

    Science.gov (United States)

    Li, Xingguang; Zai, Junjie; Liu, Haizhou; Feng, Yi; Li, Fan; Wei, Jing; Zou, Sen; Yuan, Zhiming; Shao, Yiming

    2016-01-01

    Following its immergence in December 2013, the recent Zaire Ebola virus (EBOV) outbreak in West Africa has spread and persisted for more than two years, making it the largest EBOV epidemic in both scale and geographical region to date. In this study, a total of 726 glycoprotein (GP) gene sequences of the EBOV full-length genome obtained from West Africa from the 2014 outbreak, combined with 30 from earlier outbreaks between 1976 and 2008 were used to investigate the genetic divergence, evolutionary history, population dynamics, and selection pressure of EBOV among distinct epidemic waves. Results from our dataset showed that no non-synonymous substitutions occurred on the GP gene coding sequences of EBOV that were likely to have affected protein structure or function in any way. Furthermore, the significantly different dN/dS ratios observed between the 2014 West African outbreak and earlier outbreaks were more likely due to the confounding presence of segregating polymorphisms. Our results highlight no robust evidence that the 2014 EBOV outbreak is fast-evolving and adapting to humans. Therefore, the unprecedented nature of the 2014 EBOV outbreak might be more likely related to non-virological elements, such as environmental and sociological factors. PMID:27767073

  5. Potential climate effect of mineral aerosols over West Africa. Part I: model validation and contemporary climate evaluation

    Science.gov (United States)

    Ji, Zhenming; Wang, Guiling; Pal, Jeremy S.; Yu, Miao

    2016-02-01

    Mineral dusts present in the atmosphere can play an important role in climate over West Africa and surrounding regions. However, current understanding regarding how dust aerosols influence climate of West Africa is very limited. In this study, a regional climate model is used to investigate the potential climatic impacts of dust aerosols. Two sets of simulations driven by reanalysis and Earth System Model boundary conditions are performed with and without the representation of dust processes. The model, regardless of the boundary forcing, captures the spatial and temporal variability of the aerosol optical depth and surface concentration. The shortwave radiative forcing of dust is negative at the surface and positive in the atmosphere, with greater changes in the spring and summer. The presence of mineral dusts causes surface cooling and lower troposphere heating, resulting in a stabilization effect and reduction in precipitation in the northern portion of the monsoon close to the dust emissions region. This results in an enhancement of precipitation to the south. While dusts cause the lower troposphere to stabilize, upper tropospheric cooling makes the region more prone to intense deep convection as is evident by a simulated increase in extreme precipitation. In a companion paper, the impacts of dust emissions on future West African climate are investigated.

  6. West Nile virus lineage 2 as a cause of zoonotic neurological disease in humans and horses in southern Africa.

    Science.gov (United States)

    Venter, Marietjie; Swanepoel, Robert

    2010-10-01

    West Nile virus (WNV) is widely distributed in South Africa, but since a few cases of neurological disease have been reported from this region, endemic lineage 2 strains were postulated to be of low virulence. Several cases of nonfatal encephalitis in humans as well as fatal cases in a foal, dog, and ostrich chicks have, however, been associated with lineage 2 WNV in South Africa. The pathogenesis of lineage 2 WNV strains was investigated using mouse neuroinvasive experiments, gene expression experiments, and genome sequence comparisons which indicated that lineage 2 strains that are highly pathogenic exist. To determine whether cases of WNV were being missed in South Africa, horses with fever and neurological disease were investigated. Several cases of WNV were identified, all associated with severe neurological disease, 85% of which had to be euthanized or died. All cases positive by RT-PCR were shown to belong to lineage 2 WNV by DNA sequencing and phylogenetic analysis. Two cases of occupational infection were investigated, including a case of zoonotic transmission to a veterinarian who performed an autopsy on one of the horses as well as a laboratory infection after a needle stick injury with a neuroinvasive lineage 2 strain. Both resulted in neurological disease. Cytokine expression was investigated in the second case to assess the immunopathogenesis of WNV. Collectively, these studies suggest that lineage 2 WNV may be significantly under estimated as a cause of neurological disease in South Africa.

  7. West African colonial civil servants in the nineteenth century : African participation in British colonial expansion in West Africa

    NARCIS (Netherlands)

    Arhin, K.

    1985-01-01

    From the 1850's to mid 1890's Africans were employed in top positions in the embryonic West African colonial services. This book contains the biographies of three of them: Ferguson on the Gold Coast, Lawson in Sierra Leone and Payne in Nigeria. All three had in common that they believed in British r

  8. Marine Communities on Oil Platforms in Gabon, West Africa: High Biodiversity Oases in a Low Biodiversity Environment

    Science.gov (United States)

    Friedlander, Alan M.; Ballesteros, Enric; Fay, Michael; Sala, Enric

    2014-01-01

    The marine biodiversity of Gabon, West Africa has not been well studied and is largely unknown. Our examination of marine communities associated with oil platforms in Gabon is the first scientific investigation of these structures and highlights the unique ecosystems associated with them. A number of species previously unknown to Gabonese waters were recorded during our surveys on these platforms. Clear distinctions in benthic communities were observed between older, larger platforms in the north and newer platforms to the south or closer to shore. The former were dominated by a solitary cup coral, Tubastraea sp., whereas the latter were dominated by the barnacle Megabalanus tintinnabulum, but with more diverse benthic assemblages compared to the northerly platforms. Previous work documented the presence of limited zooxanthellated scleractinian corals on natural rocky substrate in Gabon but none were recorded on platforms. Total estimated fish biomass on these platforms exceeded one ton at some locations and was dominated by barracuda (Sphyraena spp.), jacks (Carangids), and rainbow runner (Elagatis bipinnulata). Thirty-four percent of fish species observed on these platforms are new records for Gabon and 6% are new to tropical West Africa. Fish assemblages closely associated with platforms had distinct amphi-Atlantic affinities and platforms likely extend the distribution of these species into coastal West Africa. At least one potential invasive species, the snowflake coral (Carijoa riisei), was observed on the platforms. Oil platforms may act as stepping stones, increasing regional biodiversity and production but they may also be vectors for invasive species. Gabon is a world leader in terrestrial conservation with a network of protected areas covering >10% of the country. Oil exploration and biodiversity conservation currently co-exist in terrestrial and freshwater ecosystems in Gabon. Efforts to increase marine protection in Gabon may benefit by including oil

  9. Using Seasonal Climate Forecasts to Guide Disaster Management: The Red Cross Experience during the 2008 West Africa Floods

    Directory of Open Access Journals (Sweden)

    Arame Tall

    2012-01-01

    Full Text Available In 2008, the seasonal forecast issued at the Seasonal Climate Outlook Forum for West Africa (PRESAO announced a high risk of above-normal rainfall for the July–September rainy season. With probabilities for above-normal rainfall of 0.45, this forecast indicated noteworthy increases in the risk of heavy rainfall. When this information reached the International Federation of Red Cross and Red Crescent Societies (IFRC West and Central Africa Office, it led to significant changes in the organization’s flood response operations. The IFRC regional office requested funds in advance of anticipated floods, prepositioned disaster relief items in strategic locations across West Africa to benefit up to 9,500 families, updated its flood contingency plans, and alerted vulnerable communities and decision-makers across the region. This forecast-based preparedness resulted in a decrease in the number of lives, property, and livelihoods lost to floods, compared to just one year prior in 2007 when similar floods claimed above 300 lives in the region. This article demonstrates how a science-based early warning informed decisions and saved lives by triggering action in anticipation of forecast events. It analyses what it took to move decision-makers to action, based on seasonal climate information, and to overcome traditional barriers to the uptake of seasonal climate information in the region, providing evidence that these barriers can be overcome. While some institutional, communication and technical barriers were addressed in 2008, many challenges remain. Scientists and humanitarians need to build more common ground.

  10. Conservation of soil organic carbon, biodiversity and the provision of other ecosystem services along climatic gradients in West Africa

    Directory of Open Access Journals (Sweden)

    E. Marks

    2009-08-01

    Full Text Available Terrestrial carbon resources are major drivers of development in West Africa. The distribution of these resources co-varies with ecosystem type and rainfall along a strong Northeast-Southwest climatic gradient. Soil organic carbon, a strong indicator of soil quality, has been severely depleted in some areas by human activities, which leads to issues of soil erosion and desertification, but this trend can be altered with appropriate management. There is significant potential to enhance existing soil carbon stores in West Africa, with benefits at the global and local scale, for atmospheric CO2 mitigation as well as supporting and provisioning ecosystem services. Three key factors impacting carbon stocks are addressed in this review: climate, biotic factors, and human activities. Climate risks must be considered in a framework of global change, especially in West Africa, where landscape managers have few resources available to adapt to climatic perturbations. Among biotic factors, biodiversity conservation paired with carbon conservation may provide a pathway to sustainable development, and biodiversity conservation is also a global priority with local benefits for ecosystem resilience, biomass productivity, and provisioning services such as foodstuffs. Finally, human management has largely been responsible for reduced carbon stocks, but this trend can be reversed through the implementation of appropriate carbon conservation strategies in the agricultural sector, as shown by multiple studies. Owing to the strong regional climatic gradient, country-level initiatives will need to consider carbon sequestration approaches for multiple ecosystem types. Given the diversity of environments, global policies must be adapted and strategies developed at the national or sub-national levels to improve carbon storage above and belowground. Initiatives of this sort must act locally at farmer scale, and focus on ecosystem services rather than on carbon

  11. Marine communities on oil platforms in Gabon, West Africa: high biodiversity oases in a low biodiversity environment.

    Directory of Open Access Journals (Sweden)

    Alan M Friedlander

    Full Text Available The marine biodiversity of Gabon, West Africa has not been well studied and is largely unknown. Our examination of marine communities associated with oil platforms in Gabon is the first scientific investigation of these structures and highlights the unique ecosystems associated with them. A number of species previously unknown to Gabonese waters were recorded during our surveys on these platforms. Clear distinctions in benthic communities were observed between older, larger platforms in the north and newer platforms to the south or closer to shore. The former were dominated by a solitary cup coral, Tubastraea sp., whereas the latter were dominated by the barnacle Megabalanus tintinnabulum, but with more diverse benthic assemblages compared to the northerly platforms. Previous work documented the presence of limited zooxanthellated scleractinian corals on natural rocky substrate in Gabon but none were recorded on platforms. Total estimated fish biomass on these platforms exceeded one ton at some locations and was dominated by barracuda (Sphyraena spp., jacks (Carangids, and rainbow runner (Elagatis bipinnulata. Thirty-four percent of fish species observed on these platforms are new records for Gabon and 6% are new to tropical West Africa. Fish assemblages closely associated with platforms had distinct amphi-Atlantic affinities and platforms likely extend the distribution of these species into coastal West Africa. At least one potential invasive species, the snowflake coral (Carijoa riisei, was observed on the platforms. Oil platforms may act as stepping stones, increasing regional biodiversity and production but they may also be vectors for invasive species. Gabon is a world leader in terrestrial conservation with a network of protected areas covering >10% of the country. Oil exploration and biodiversity conservation currently co-exist in terrestrial and freshwater ecosystems in Gabon. Efforts to increase marine protection in Gabon may benefit by

  12. Marine communities on oil platforms in Gabon, West Africa: high biodiversity oases in a low biodiversity environment.

    Science.gov (United States)

    Friedlander, Alan M; Ballesteros, Enric; Fay, Michael; Sala, Enric

    2014-01-01

    The marine biodiversity of Gabon, West Africa has not been well studied and is largely unknown. Our examination of marine communities associated with oil platforms in Gabon is the first scientific investigation of these structures and highlights the unique ecosystems associated with them. A number of species previously unknown to Gabonese waters were recorded during our surveys on these platforms. Clear distinctions in benthic communities were observed between older, larger platforms in the north and newer platforms to the south or closer to shore. The former were dominated by a solitary cup coral, Tubastraea sp., whereas the latter were dominated by the barnacle Megabalanus tintinnabulum, but with more diverse benthic assemblages compared to the northerly platforms. Previous work documented the presence of limited zooxanthellated scleractinian corals on natural rocky substrate in Gabon but none were recorded on platforms. Total estimated fish biomass on these platforms exceeded one ton at some locations and was dominated by barracuda (Sphyraena spp.), jacks (Carangids), and rainbow runner (Elagatis bipinnulata). Thirty-four percent of fish species observed on these platforms are new records for Gabon and 6% are new to tropical West Africa. Fish assemblages closely associated with platforms had distinct amphi-Atlantic affinities and platforms likely extend the distribution of these species into coastal West Africa. At least one potential invasive species, the snowflake coral (Carijoa riisei), was observed on the platforms. Oil platforms may act as stepping stones, increasing regional biodiversity and production but they may also be vectors for invasive species. Gabon is a world leader in terrestrial conservation with a network of protected areas covering >10% of the country. Oil exploration and biodiversity conservation currently co-exist in terrestrial and freshwater ecosystems in Gabon. Efforts to increase marine protection in Gabon may benefit by including oil

  13. Conservation of soil organic carbon, biodiversity and the provision of other ecosystem services along climatic gradients in West Africa

    Directory of Open Access Journals (Sweden)

    E. Marks

    2008-11-01

    Full Text Available Terrestrial carbon resources are major drivers of development in West Africa. The distribution of these resources co-varies with ecosystem type and rainfall along a strong Northeast-Southwest climatic gradient. Soil organic carbon, a strong indicator of soil quality, has been severely depleted in some areas by human activities, which leads to issues of soil erosion and desertification, but this trend can be altered via appropriate management. There is significant potential to enhance existing soil carbon stores in West Africa, with benefits at the global and local scales, for atmospheric CO2 mitigation and supporting, and provisioning ecosystem services, respectively. Three key factors impacting carbon stocks are addressed in this review: climate, biotic factors, and human activities. Climate risks must be considered in a framework of global change, especially in West Africa, where landscape managers have few resources available to adapt to climatic perturbations. Among biotic factors, biodiversity conservation paired with carbon conservation may provide a pathway to sustainable development, as evidence suggests that both may be inter-linked, and biodiversity conservation is also a global priority with local benefits for ecosystem resilience, biomass productivity, and provisioning services such as foodstuffs. Finally, human management has largely been responsible for reduced carbon stocks, but this trend can be reversed through the implementation of appropriate carbon conservation strategies in the agricultural sector, as shown by multiple studies. Owing to the strong regional climatic gradient, country-level initiatives will need to consider carbon sequestration approaches for multiple ecosystem types. Given the diversity of environments, global policies must be adapted and strategised at the national or sub-national levels to improve C storage above and belowground. Initiatives of this sort must act locally at farmer scale, and

  14. West Africa Extreme Rainfall Events and Large-Scale Ocean Surface and Atmospheric Conditions in the Tropical Atlantic

    Directory of Open Access Journals (Sweden)

    S. Ta

    2016-01-01

    Full Text Available Based on daily precipitation from the Global Precipitation Climatology Project (GPCP data during April–October of the 1997–2014 period, the daily extreme rainfall trends and variability over West Africa are characterized using 90th-percentile threshold at each grid point. The contribution of the extreme rainfall amount reaches ~50–90% in the northern region while it is ~30–50% in the south. The yearly cumulated extreme rainfall amount indicates significant and negative trends in the 6°N–12°N; 6°N–12°N; 17°W–10°W and 4°N–7°N; 4°N–7°N; 6°E–10°E 4°N–7°N; 6°E–10°E 4°N–7°N; 6°E–10°E domains, while the number of days exhibits nonsignificant trends over West Africa. The empirical orthogonal functions performed on the standardized anomalies show four variability modes that include all West Africa with a focus on the Sahelian region, the eastern region including the south of Nigeria, the western part including Guinea, Sierra Leone, Liberia, and Guinea-Bissau, and finally a small region at the coast of Ghana and Togo. These four modes are influenced differently by the large-scale ocean surface and atmospheric conditions in the tropical Atlantic. The results are applicable in planning the risks associated with these climate hazards, particularly on water resource management and civil defense.

  15. Reflections on the Upheaval of West Asia and North Africa%西亚北非变局的反思

    Institute of Scientific and Technical Information of China (English)

    刘小勤

    2011-01-01

    Political unrests triggered in the countries in West Asia and North Africa are neither unexpected events,nor "endogenous events" declared by some scholars in an early period.It results from the conflicts in the political,economic,and social development of the countries in West Asia and north Africa,and the outside inducement of the Middle East reforming policy and the network diplomacy propelled by The United States and other western countries.It is an all-round social oscillation intertwined with internal and external factors.Reflections on West Asia and North Africa upheavals have deep enlightenments on the social and economic development of the developing countries,including our country.%引发西亚北非等国的政治动荡并不是偶然的突发性事件,也不是一些学者在早期所断言的"内生性事件",究其原因,有西亚北非国家自身政治、经济、社会发展矛盾的集中凸显,也有美国等西方国家推行改造中东、推行网络外交的外部诱因,是一场内外因素相互交织、综合作用下的社会全面动荡。西亚北非变局对于包括我国在内的发展中国家的社会经济发展具有深刻的启示。

  16. Phylogeographic reconstruction of African yellow fever virus isolates indicates recent simultaneous dispersal into east and west Africa.

    Directory of Open Access Journals (Sweden)

    Andrew Beck

    Full Text Available Yellow fever virus (YFV is a mosquito-borne flavivirus that is a major public health problem in tropical areas of Africa and South America. There have been detailed studies on YFV ecology in West Africa and South America, but current understanding of YFV circulation on the African continent is incomplete. This inadequacy is especially notable for East and Central Africa, for which the unpredictability of human outbreaks is compounded by limitations in both historical and present surveillance efforts. Sparse availability of nucleotide sequence data makes it difficult to investigate the dispersal of YFV in these regions of the continent. To remedy this, we constructed Bayesian phylogenetic and geographic analyses utilizing 49 partial genomic sequences to infer the structure of YFV divergence across the known range of the virus on the African continent. Relaxed clock analysis demonstrated evidence for simultaneous divergence of YFV into east and west lineages, a finding that differs from previous hypotheses of YFV dispersal from reservoirs located on edges of the endemic range. Using discrete and continuous geographic diffusion models, we provide detailed structure of YFV lineage diversity. Significant transition links between extant East and West African lineages are presented, implying connection between areas of known sylvatic cycling. The results of demographic modeling reinforce the existence of a stably maintained population of YFV with spillover events into human populations occurring periodically. Geographically distinct foci of circulation are reconstructed, which have significant implications for studies of YFV ecology and emergence of human disease. We propose further incorporation of Bayesian phylogeography into formal GIS analyses to augment studies of arboviral disease.

  17. Conservation of soil organic carbon, biodiversity and the provision of other ecosystem services along climatic gradients in West Africa

    Science.gov (United States)

    Marks, E.; Aflakpui, G. K. S.; Nkem, J.; Poch, R. M.; Khouma, M.; Kokou, K.; Sagoe, R.; Sebastiã, M.-T.

    2009-08-01

    Terrestrial carbon resources are major drivers of development in West Africa. The distribution of these resources co-varies with ecosystem type and rainfall along a strong Northeast-Southwest climatic gradient. Soil organic carbon, a strong indicator of soil quality, has been severely depleted in some areas by human activities, which leads to issues of soil erosion and desertification, but this trend can be altered with appropriate management. There is significant potential to enhance existing soil carbon stores in West Africa, with benefits at the global and local scale, for atmospheric CO2 mitigation as well as supporting and provisioning ecosystem services. Three key factors impacting carbon stocks are addressed in this review: climate, biotic factors, and human activities. Climate risks must be considered in a framework of global change, especially in West Africa, where landscape managers have few resources available to adapt to climatic perturbations. Among biotic factors, biodiversity conservation paired with carbon conservation may provide a pathway to sustainable development, and biodiversity conservation is also a global priority with local benefits for ecosystem resilience, biomass productivity, and provisioning services such as foodstuffs. Finally, human management has largely been responsible for reduced carbon stocks, but this trend can be reversed through the implementation of appropriate carbon conservation strategies in the agricultural sector, as shown by multiple studies. Owing to the strong regional climatic gradient, country-level initiatives will need to consider carbon sequestration approaches for multiple ecosystem types. Given the diversity of environments, global policies must be adapted and strategies developed at the national or sub-national levels to improve carbon storage above and belowground. Initiatives of this sort must act locally at farmer scale, and focus on ecosystem services rather than on carbon sequestration solely.

  18. Region-wide assessment of the capacity for human nutrition training in West Africa: current situation, challenges, and way forward

    Directory of Open Access Journals (Sweden)

    Roger Sodjinou

    2014-01-01

    Full Text Available Background: There is a dearth of information on existing nutrition training programs in West Africa. A preliminary step in the process of developing a comprehensive framework to strengthen human capacity for nutrition is to conduct an inventory of existing training programs. Objective: This study was conducted to provide baseline data on university-level nutrition training programs that exist in the 16 countries in West Africa. It also aimed to identify existing gaps in nutrition training and propose solutions to address them. Design: Participating institutions were identified based on information provided by in-country key informants, UNICEF offices or through internet searches. Data were collected through semi-structured interviews during on-site visits or through self-administered questionnaires. Simple descriptive and bivariate analyses were performed. Results: In total, 83 nutrition degree programs comprising 32 B.Sc. programs, 34 M.Sc. programs, and 17 Ph.D. programs were identified in the region. More than half of these programs were in Nigeria. Six countries (Cape Verde, Guinea-Bissau, Liberia, Mali, The Gambia, and Togo offered no nutrition degree program. The programs in francophone countries were generally established more recently than those in anglophone countries (age: 3.5 years vs. 21.4 years. Programs were predominantly (78% run by government-supported institutions. They did not provide a comprehensive coverage of all essential aspects of human nutrition. They were heavily oriented to food science (46%, with little emphasis on public health nutrition (24% or overnutrition (2%. Annual student intakes per program in 2013 ranged from 3 to 262; 7 to 40; and 3 to 10, respectively, for bachelor's, master's, and doctoral programs while the number of graduates produced annually per country ranged from 6 to 271; 3 to 64; and 1 to 18, respectively. External collaboration only existed in 15% of the programs. In-service training programs on

  19. Impact of deep convection in the tropical tropopause layer in West Africa: in-situ observations and mesoscale modelling

    OpenAIRE

    Fierli, F.; E. Orlandi; Law, K. S.; C. Cagnazzo; Borrmann, S.; F. Cairo; Schiller, C.; F. Ravegnani; Volk, M

    2011-01-01

    We present the analysis of the impact of convection on the composition of the tropical tropopause layer region (TTL) in West-Africa during the AMMA-SCOUT campaign. Geophysica M55 aircraft observations of water vapor, ozone, aerosol and CO2 during August 2006 show perturbed values at altitudes ranging from 14 km to 17 km (above the main convective outflow) and satellite data indicates that air detrainment is likely to have originated from convective cloud east of the flights. Simulations of th...

  20. HIV Status Disclosure and Retention in Care in HIV-Infected Adolescents on Antiretroviral Therapy (ART) in West Africa

    OpenAIRE

    Elise Arrivé; Fatoumata Dicko; Hind Amghar; Addi Edmond Aka; Hélène Dior; Belinda Bouah; Mariam Traoré; Patricia Ogbo; Hortense Aka Dago-Akribi; Tanoh Kassi F Eboua; Kouadio Kouakou; Haby Signate Sy; Ahmadou Alioum; François Dabis; Didier Koumavi Ekouévi

    2012-01-01

    OBJECTIVE: We assessed the effect of HIV status disclosure on retention in care from initiation of antiretroviral therapy (ART) among HIV-infected children aged 10 years or more in Cote d'Ivoire, Mali and Sénégal. METHODS: Multi-centre cohort study within five paediatric clinics participating in the IeDEA West Africa collaboration. HIV-infected patients were included in this study if they met the following inclusion criteria: aged 10-21 years while on ART; having initiated ART ≥ 200 days befo...

  1. Modeling malaria infection and immunity against variant surface antigens in Príncipe Island, West Africa

    DEFF Research Database (Denmark)

    Bandeiras, Cátia; Trovoada, Maria Jesus; Gonçalves, Lígia A;

    2014-01-01

    the impact of reducing exposure to the parasite on the immune repertoire against P. falciparum erythrocyte membrane protein 1 (PfEMP1) variants. The model was parameterized with data from Príncipe Island, West Africa, and applied to simulate two alternative transmission scenarios: one where control measures......-control values, while the re-acquisition of the immune repertoire against PfEMP1 is slower, creating a window for increased severity. The model illustrates the consequences of loss of immune repertoire against PfEMP1 in a given setting and can be applied to other regions where similar data may be available....

  2. Subsurface Fires in Mali: Refutation of Active Volcanism Hypothesis in West-Central Africa

    Science.gov (United States)

    Bandlien, E. H.; Svensen, H.; Dysthe, D. K.; Planke, S.

    2002-12-01

    .P. This suggests that subsurface fires might have been common in the Trans-Saharan region previously, and that the stratigraphic record from the Holocene lakes should be correlated with data from areas with modern subsurface fires. We argue that the phenomena previously being attributed to volcanism in the Lac Faguibine area were caused by subsurface combustion of organic material. An important consequence of this conclusion is that west-central Africa should be regarded as volcanologically inactive, and that possible reactivations of the major EW trending Guinea-Nubian lineament is not associated with volcanism.

  3. A Comparative Study on Satellite- and Model-Based Crop Phenology in West Africa

    Directory of Open Access Journals (Sweden)

    Elodie Vintrou

    2014-02-01

    Full Text Available Crop phenology is essential for evaluating crop production in the food insecure regions of West Africa. The aim of the paper is to study whether satellite observation of plant phenology are consistent with ground knowledge of crop cycles as expressed in agro-simulations. We used phenological variables from a MODIS Land Cover Dynamics (MCD12Q2 product and examined whether they reproduced the spatio-temporal variability of crop phenological stages in Southern Mali. Furthermore, a validated cereal crop growth model for this region, SARRA-H (System for Regional Analysis of Agro-Climatic Risks, provided precise agronomic information. Remotely-sensed green-up, maturity, senescence and dormancy MODIS dates were extracted for areas previously identified as crops and were compared with simulated leaf area indices (LAI temporal profiles generated using the SARRA-H crop model, which considered the main cropping practices. We studied both spatial (eight sites throughout South Mali during 2007 and temporal (two sites from 2002 to 2008 differences between simulated crop cycles and determined how the differences were indicated in satellite-derived phenometrics. The spatial comparison of the phenological indicator observations and simulations showed mainly that (i the satellite-derived start-of-season (SOS was detected approximately 30 days before the model-derived SOS; and (ii the satellite-derived end-of-season (EOS was typically detected 40 days after the model-derived EOS. Studying the inter-annual difference, we verified that the mean bias was globally consistent for different climatic conditions. Therefore, the land cover dynamics derived from the MODIS time series can reproduce the spatial and temporal variability of different start-of-season and end-of-season crop species. In particular, we recommend simultaneously using start-of-season phenometrics with crop models for yield forecasting to complement commonly used climate data and provide a better

  4. The Sahel Region of West Africa: Examples of Climate Analyses Motivated By Drought Management Needs

    Science.gov (United States)

    Ndiaye, O.; Ward, M. N.; Siebert, A. B.

    2011-12-01

    The Sahel is one of the most drought-prone regions in the world. This paper focuses on climate sources of drought, and some new analyses mostly driven by users needing climate information to help in drought management strategies. The Sahel region of West Africa is a transition zone between equatorial climate and vegetation to the south, and desert to the north. The climatology of the region is dominated by dry conditions for most of the year, with a single peak in rainfall during boreal summer. The seasonal rainfall total contains both interannual variability and substantial decadal to multidecadal variability (MDV). This brings climate analysis and drought management challenges across this range of timescales. The decline in rainfall from the wet decades of the 1950s and 60s to the dry decades of the 1970s and 80s has been well documented. In recent years, a moderate recovery has emerged, with seasonal totals in the period 1994-2010 significantly higher than the average rainfall 1970-1993. These MDV rainfall fluctuations have expression in large-scale sea-surface temperature fluctuations in all ocean basins, placing the changes in drought frequency within broader ocean-atmosphere climate fluctuation. We have evaluated the changing character of low seasonal rainfall total event frequencies in the Sahel region 1950-2010, highlighting the role of changes in the mean, variance and distribution shape of seasonal rainfall totals as the climate has shifted through the three observed phases. We also consider the extent to which updating climate normals in real-time can damp the bias in expected event frequency, an important issue for the feasibility of index insurance as a drought management tool in the presence of a changing climate. On the interannual timescale, a key factor long discussed for agriculture is the character of rainfall onset. An extended dry spell often occurs early in the rainy season before the crop is fully established, and this often leads to crop

  5. Exposure Patterns Driving Ebola Transmission in West Africa: A Retrospective Observational Study

    Science.gov (United States)

    Agua-Agum, Junerlyn; Aylward, Bruce; Bawo, Luke; Blake, Isobel M.; Brennan, Richard J.; Cawthorne, Amy; Cleary, Eilish; Clement, Peter; Conteh, Roland; Cori, Anne; Dafae, Foday; Dahl, Benjamin; Dangou, Jean-Marie; Diallo, Boubacar; Donnelly, Christl A.; Dye, Christopher; Eckmanns, Tim; Fallah, Mosoka; Fiebig, Lena; Fraser, Christophe; Garske, Tini; Gonzalez, Lice; Hamblion, Esther; Hamid, Nuha; Hinsley, Wes; Jambei, Amara; Jombart, Thibaut; Kargbo, David; Keita, Sakoba; Kinzer, Michael; George, Fred Kuti; Godefroy, Beatrice; Gutierrez, Giovanna; Kannangarage, Niluka; Mills, Harriet L.; Moller, Thomas; Meijers, Sascha; Mohamed, Yasmine; Newton, Emily; Nouvellet, Pierre; Nyenswah, Tolbert; Perea, William; Perkins, Devin; Riley, Steven; Rondy, Marc; Sagrado, Maria; Savulescu, Camelia; Schafer, Ilana J.; Schumacher, Dirk; Seyler, Thomas; Shah, Anita; Van Kerkhove, Maria D.; Wesseh, C. Samford; Yoti, Zabulon

    2016-01-01

    Background The ongoing West African Ebola epidemic began in December 2013 in Guinea, probably from a single zoonotic introduction. As a result of ineffective initial control efforts, an Ebola outbreak of unprecedented scale emerged. As of 4 May 2015, it had resulted in more than 19,000 probable and confirmed Ebola cases, mainly in Guinea (3,529), Liberia (5,343), and Sierra Leone (10,746). Here, we present analyses of data collected during the outbreak identifying drivers of transmission and highlighting areas where control could be improved. Methods and Findings Over 19,000 confirmed and probable Ebola cases were reported in West Africa by 4 May 2015. Individuals with confirmed or probable Ebola (“cases”) were asked if they had exposure to other potential Ebola cases (“potential source contacts”) in a funeral or non-funeral context prior to becoming ill. We performed retrospective analyses of a case line-list, collated from national databases of case investigation forms that have been reported to WHO. These analyses were initially performed to assist WHO’s response during the epidemic, and have been updated for publication. We analysed data from 3,529 cases in Guinea, 5,343 in Liberia, and 10,746 in Sierra Leone; exposures were reported by 33% of cases. The proportion of cases reporting a funeral exposure decreased over time. We found a positive correlation (r = 0.35, p < 0.001) between this proportion in a given district for a given month and the within-district transmission intensity, quantified by the estimated reproduction number (R). We also found a negative correlation (r = −0.37, p < 0.001) between R and the district proportion of hospitalised cases admitted within ≤4 days of symptom onset. These two proportions were not correlated, suggesting that reduced funeral attendance and faster hospitalisation independently influenced local transmission intensity. We were able to identify 14% of potential source contacts as cases in the case line

  6. WASCAL - West African Science Service Center on Climate Change and Adapted Land Use Regional Climate Simulations and Land-Atmosphere Simulations for West Africa at DKRZ and elsewhere

    Science.gov (United States)

    Hamann, Ilse; Arnault, Joel; Bliefernicht, Jan; Klein, Cornelia; Heinzeller, Dominikus; Kunstmann, Harald

    2014-05-01

    Changing climate and hydro-meteorological boundary conditions are among the most severe challenges to Africa in the 21st century. In particular West Africa faces an urgent need to develop effective adaptation and mitigation strategies to cope with negative impacts on humans and environment due to climate change, increased hydro-meteorological variability and land use changes. To help meet these challenges, the German Federal Ministry of Education and Research (BMBF) started an initiative with institutions in Germany and West African countries to establish together a West African Science Service Center on Climate Change and Adapted Land Use (WASCAL). This activity is accompanied by an establishment of trans-boundary observation networks, an interdisciplinary core research program and graduate research programs on climate change and related issues for strengthening the analytical capabilities of the Science Service Center. A key research activity of the WASCAL Competence Center is the provision of regional climate simulations in a fine spatio-temporal resolution for the core research sites of WASCAL for the present and the near future. The climate information is needed for subsequent local climate impact studies in agriculture, water resources and further socio-economic sectors. The simulation experiments are performed using regional climate models such as COSMO-CLM, RegCM and WRF and statistical techniques for a further refinement of the projections. The core research sites of WASCAL are located in the Sudanian Savannah belt in Northern Ghana, Southern Burkina Faso and Northern Benin. The climate in this region is semi-arid with six rainy months. Due to the strong population growth in West Africa, many areas of the Sudanian Savannah have been already converted to farmland since the majority of the people are living directly or indirectly from the income produced in agriculture. The simulation experiments of the Competence Center and the Core Research Program are

  7. Characteristics of HIV-2 and HIV-1/HIV-2 Dually Seropositive Adults in West Africa Presenting for Care and Antiretroviral Therapy: The IeDEA-West Africa HIV-2 Cohort Study.

    Directory of Open Access Journals (Sweden)

    Didier K Ekouevi

    Full Text Available HIV-2 is endemic in West Africa. There is a lack of evidence-based guidelines on the diagnosis, management and antiretroviral therapy (ART for HIV-2 or HIV-1/HIV-2 dual infections. Because of these issues, we designed a West African collaborative cohort for HIV-2 infection within the framework of the International epidemiological Databases to Evaluate AIDS (IeDEA.We collected data on all HIV-2 and HIV-1/HIV-2 dually seropositive patients (both ARV-naive and starting ART and followed-up in clinical centres in the IeDEA-WA network including a total of 13 clinics in five countries: Benin, Burkina-Faso Côte d'Ivoire, Mali, and Senegal, in the West Africa region.Data was merged for 1,754 patients (56% female, including 1,021 HIV-2 infected patients (551 on ART and 733 dually seropositive for both HIV-1 and HIV 2 (463 on ART. At ART initiation, the median age of HIV-2 patients was 45.3 years, IQR: (38.3-51.7 and 42.4 years, IQR (37.0-47.3 for dually seropositive patients (p = 0.048. Overall, 16.7% of HIV-2 patients on ART had an advanced clinical stage (WHO IV or CDC-C. The median CD4 count at the ART initiation is 166 cells/mm(3, IQR (83-247 among HIV-2 infected patients and 146 cells/mm(3, IQR (55-249 among dually seropositive patients. Overall, in ART-treated patients, the CD4 count increased 126 cells/mm(3 after 24 months on ART for HIV-2 patients and 169 cells/mm(3 for dually seropositive patients. Of 551 HIV-2 patients on ART, 5.8% died and 10.2% were lost to follow-up during the median time on ART of 2.4 years, IQR (0.7-4.3.This large multi-country study of HIV-2 and HIV-1/HIV-2 dual infection in West Africa suggests that routine clinical care is less than optimal and that management and treatment of HIV-2 could be further informed by ongoing studies and randomized clinical trials in this population.

  8. Characteristics of HIV-2 and HIV-1/HIV-2 Dually Seropositive Adults in West Africa Presenting for Care and Antiretroviral Therapy: The IeDEA-West Africa HIV-2 Cohort Study

    Science.gov (United States)

    Ekouevi, Didier K.; Balestre, Eric; Coffie, Patrick A.; Minta, Daouda; Messou, Eugene; Sawadogo, Adrien; Minga, Albert; Sow, Papa Salif; Bissagnene, Emmanuel; Eholie, Serge P.; Gottlieb, Geoffrey S.; Dabis, François; Zannou, Djimon Marcel; Ahouada, Carin; Akakpo, Jocelyn; Ahomadegbé, Christelle; Bashi, Jules; Gougounon-Houéto, Alice; Azon-Kouanou, Angèle; Houngbé, Fabien; Koumakpaï, Sikiratou; Alihonou, Florence; d’Almeida, Marcelline; Hodonou, Irvine; Hounhoui, Ghislaine; Sagbo, Gracien; Tossa-Bagnan, Leïla; Adjide, Herman; Drabo, Joseph; Bognounou, René; Dienderé, Arnaud; Traore, Eliezer; Zoungrana, Lassane; Zerbo, Béatrice; Sawadogo, Adrien Bruno; Zoungrana, Jacques; Héma, Arsène; Soré, Ibrahim; Bado, Guillaume; Tapsoba, Achille; Yé, Diarra; Kouéta, Fla; Ouedraogo, Sylvie; Ouédraogo, Rasmata; Hiembo, William; Gansonré, Mady; Messou, Eugène; Gnokoro, Joachim Charles; Koné, Mamadou; Kouakou, Guillaume Martial; Bosse, Clarisse Amani; Brou, Kouakou; Assi, Achi Isidore; Chenal, Henri; Hawerlander, Denise; Soppi, Franck; Minga, Albert; Abo, Yao; Bomisso, Germain; Eholié, Serge Paul; Amego, Mensah Deborah Noelly; Andavi, Viviane; Diallo, Zelica; Ello, Frédéric; Tanon, Aristophane Koffi; Koule, Serge Olivier; Anzan, Koffi Charles; Guehi, Calixte; Aka, Edmond Addi; Issouf, Koffi Ladji; Kouakou, Jean-Claude; N’Gbeche, Marie-Sylvie; Touré, Pety; Avit-Edi, Divine; Kouakou, Kouadio; Moh, Magloire; Yao, Valérie Andoblé; Folquet, Madeleine Amorissani; Dainguy, Marie-Evelyne; Kouakou, Cyrille; Méa-Assande, Véronique Tanoh; Oka-Berete, Gladys; Zobo, Nathalie; Acquah, Patrick; Kokora, Marie-Berthe; Eboua, Tanoh François; Timité-Konan, Marguerite; Ahoussou, Lucrèce Diecket; Assouan, Julie Kebé; Sami, Mabéa Flora; Kouadio, Clémence; Renner, Lorna; Goka, Bamenla; Welbeck, Jennifer; Sackey, Adziri; Owiafe, Seth Ntiri; Wejse, Christian; Silva, Zacarias José Da; Paulo, Joao; Rodrigues, Amabelia; da Silva, David; Medina, Candida; Oliviera-Souto, Ines; Østergaard, Lars; Laursen, Alex; Sodemann, Morten; Aaby, Peter; Fomsgaard, Anders; Erikstrup, Christian; Eugen-Olsen, Jesper; Maïga, Moussa Y; Diakité, Fatoumata Fofana; Kalle, Abdoulaye; Katile, Drissa; Traore, Hamar Alassane; Minta, Daouda; Cissé, Tidiani; Dembelé, Mamadou; Doumbia, Mohammed; Fomba, Mahamadou; Kaya, Assétou Soukho; Traoré, Abdoulaye M; Traoré, Hamady; Toure, Amadou Abathina; Dicko, Fatoumata; Sylla, Mariam; Berthé, Alima; Traoré, Hadizatou Coulibaly; Koïta, Anta; Koné, Niaboula; N'Diaye, Clémentine; Coulibaly, Safiatou Touré; Traoré, Mamadou; Traoré, Naïchata; Charurat, Man; Ajayi, Samuel; Dapiap, Stephen; Otu; Igbinoba, Festus; Benson, Okwara; Adebamowo, Clément; James, Jesse; Obaseki; Osakede, Philip; Olasode, John; Sow, Papa Salif; Diop, Bernard; Manga, Noël Magloire; Tine, Judicael Malick; Signate Sy, Haby; Ba, Abou; Diagne, Aida; Dior, Hélène; Faye, Malick; Gueye, Ramatoulaye Diagne; Mbaye, Aminata Diack; Patassi, Akessiwe; Kotosso, Awèrou; Kariyare, Benjamin Goilibe; Gbadamassi, Gafarou; Komi, Agbo; Mensah-Zukong, Kankoé Edem; Pakpame, Pinuwe; Lawson-Evi, Annette Koko; Atakouma, Yawo; Takassi, Elom; Djeha, Améyo; Ephoévi-gah, Ayoko; Djibril, Sherifa El-Hadj; Dabis, François; Bissagnene, Emmanuel; Arrivé, Elise; Coffie, Patrick; Ekouevi, Didier; Jaquet, Antoine; Leroy, Valériane; Lewden, Charlotte; Sasco, Annie; Azani, Jean-Claude; Allou, Gérard; Balestre, Eric; Bohossou, Franck; Karcher, Sophie; Gonsan, Jules Mahan; Carrou, Jérôme Le; Lenaud, Séverin; Nchot, Célestin; Malateste, Karen; Yao, Amon Roseamonde; Siloué, Bertine; Clouet, Gwenaelle; Djetouan, Hugues; Doring, Alexandra; Kouakou, Adrienne; Rabourdin, Elodie; Rivenc, Jean; Anglaret, Xavier; Ba, Boubacar; Essanin, Jean Bosco; Ciaranello, Andrea; Datté, Sébastien; Desmonde, Sophie; Diby, Jean-Serge Elvis; Gottlieb, Geoffrey S.; Horo, Apollinaire Gninlgninrin; Kangah, Serge N'zoré; Malvy, Denis; Meless, David; Mounkaila-Harouna, Aida; Ndondoki, Camille; Shiboski, Caroline; Thiébaut, Rodolphe; PAC-CI; Abidjan

    2013-01-01

    Background HIV-2 is endemic in West Africa. There is a lack of evidence-based guidelines on the diagnosis, management and antiretroviral therapy (ART) for HIV-2 or HIV-1/HIV-2 dual infections. Because of these issues, we designed a West African collaborative cohort for HIV-2 infection within the framework of the International epidemiological Databases to Evaluate AIDS (IeDEA). Methods We collected data on all HIV-2 and HIV-1/HIV-2 dually seropositive patients (both ARV-naive and starting ART) and followed-up in clinical centres in the IeDEA-WA network including a total of 13 clinics in five countries: Benin, Burkina-Faso Côte d’Ivoire, Mali, and Senegal, in the West Africa region. Results Data was merged for 1,754 patients (56% female), including 1,021 HIV-2 infected patients (551 on ART) and 733 dually seropositive for both HIV-1 and HIV 2 (463 on ART). At ART initiation, the median age of HIV-2 patients was 45.3 years, IQR: (38.3–51.7) and 42.4 years, IQR (37.0–47.3) for dually seropositive patients (p = 0.048). Overall, 16.7% of HIV-2 patients on ART had an advanced clinical stage (WHO IV or CDC-C). The median CD4 count at the ART initiation is 166 cells/mm3, IQR (83–247) among HIV-2 infected patients and 146 cells/mm3, IQR (55–249) among dually seropositive patients. Overall, in ART-treated patients, the CD4 count increased 126 cells/mm3 after 24 months on ART for HIV-2 patients and 169 cells/mm3 for dually seropositive patients. Of 551 HIV-2 patients on ART, 5.8% died and 10.2% were lost to follow-up during the median time on ART of 2.4 years, IQR (0.7–4.3). Conclusions This large multi-country study of HIV-2 and HIV-1/HIV-2 dual infection in West Africa suggests that routine clinical care is less than optimal and that management and treatment of HIV-2 could be further informed by ongoing studies and randomized clinical trials in this population. PMID:23824279

  9. The monetary value of human milk in Francophone west Africa: a PROFILES analysis for nutrition policy communication.

    Science.gov (United States)

    Aguayo, Víctor M; Ross, Jay

    2002-06-01

    Using a simple and conservative methodology, we estimated the volume and monetary value of the human milk produced by lactating women in Francophone West Africa. In that region, children zero to 35.9 months old consume over 1.1 billion liters of human milk per year. However, suboptimal breastfeeding practices account for the loss of 175 million liters of human milk annually. If the human milk consumed by children zero to 35.9 months old were to be adequately replaced using commercial breastmilk substitutes, an annual expenditure of about 2 billion US dollars would be needed. At the household level, the annual replacement cost of human milk would amount to US$412 per infant. This is beyond the reach of most families in West Africa, where as many as 61% of families in some countries live on less than one US dollar per day. Appropriate policies to foster breastfeeding need to be developed and adequately implemented. Such policy action is more likely to occur if decision makers fully appreciate the monetary value of human milk.

  10. Changes in Intense Precipitation Events in West Africa and the central U.S. under Global Warming

    Energy Technology Data Exchange (ETDEWEB)

    Cook, Kerry H. [Univ. of Texas, Austin, TX (United States); Vizy, Edward [Univ. of Texas, Austin, TX (United States)

    2016-02-08

    The purpose of the proposed project is to improve our understanding of the physical processes and large-scale connectivity of changes in intense precipitation events (high rainfall rates) under global warming in West Africa and the central U.S., including relationships with low-frequency modes of variability. This is in response to the requested subject area #2 “simulation of climate extremes under a changing climate … to better quantify the frequency, duration, and intensity of extreme events under climate change and elucidate the role of low frequency climate variability in modulating extremes.” We will use a regional climate model and emphasize an understanding of the physical processes that lead to an intensification of rainfall. The project objectives are as follows: 1. Understand the processes responsible for simulated changes in warm-season rainfall intensity and frequency over West Africa and the Central U.S. associated with greenhouse gas-induced global warming 2. Understand the relationship between changes in warm-season rainfall intensity and frequency, which generally occur on regional space scales, and the larger-scale global warming signal by considering modifications of low-frequency modes of variability. 3. Relate changes simulated on regional space scales to global-scale theories of how and why atmospheric moisture levels and rainfall should change as climate warms.

  11. Solar drying of mangoes: preservation of an important source of vitamin A in French-speaking West Africa.

    Science.gov (United States)

    Rankins, Jenice; Sathe, Shridhar K; Spicer, Maria T

    2008-06-01

    Vitamin A deficiency, which is especially widespread among children younger than age 5 years, is a major barrier to reducing child mortality rates in French-speaking West Africa. A large amount of an indigenous plant source of provitamin A carotenoids are lost to postharvest waste. For example, the postharvest loss of mangoes in the region exceeds an annual total of 100,000 metric tons. In our study, 3.75 metric tons of fresh mangoes were dried using a solar dryer to a final moisture content of 10% to 12%, yielding a total of 360 kg dried mango. The product analysis revealed 4,000+/-500 microg beta carotene/100 g and 3,680+/-150 microg beta carotene/100 g after 2 and 6 months of storage, respectively. Thus, one greenhouse solar dryer is capable of reducing postharvest mango waste by 3.75 tons providing up to 1.15 million retinol activity equivalents of dietary vitamin A. The use of this technology that requires solar energy and manpower has the potential of increasing dietary vitamin A supply by up to 27,000-fold, compared to the currently available vitamin A in the region. Moreover, mango is a fruit that is well-liked by the population in this geographic area increasing the likelihood of its ready acceptance. Reducing postharvest loss of mangoes by using greenhouse model solar dryers is a promising strategy to help combat vitamin A deficiency in French-speaking West Africa.

  12. Africa

    DEFF Research Database (Denmark)

    Mol, Michael J.; Stadler, Christian; Ariño, Africa

    2017-01-01

    Context matters in the global strategy literature. We discuss how Africa, as a setting that received limited attention in the past, offers opportunity to challenge existing theory and develop new insights. The overall goal is to ask: What will the field of global strategic management look like once...... we have engaged with Africa in a similar manner as we have done with other emerging economies? We also introduce the papers published in this special issue and highlight directions for future research....

  13. Characterization of Enteroviruses from non-human primates in cameroon revealed virus types widespread in humans along with candidate new types and species.

    Directory of Open Access Journals (Sweden)

    Serge Alain Sadeuh-Mba

    Full Text Available Enteroviruses (EVs infecting African Non-Human Primates (NHP are still poorly documented. This study was designed to characterize the genetic diversity of EVs among captive and wild NHP in Cameroon and to compare this diversity with that found in humans. Stool specimens were collected in April 2008 in NHP housed in sanctuaries in Yaounde and neighborhoods. Moreover, stool specimens collected from wild NHP from June 2006 to October 2008 in the southern rain forest of Cameroon were considered. RNAs purified directly from stool samples were screened for EVs using a sensitive RT-nested PCR targeting the VP1 capsid coding gene whose nucleotide sequence was used for molecular typing. Captive chimpanzees (Pan troglodytes and gorillas (Gorilla gorilla were primarily infected by EV types already reported in humans in Cameroon and elsewhere: Coxsackievirus A13 and A24, Echovirus 15 and 29, and EV-B82. Moreover EV-A119, a novel virus type recently described in humans in central and west Africa, was also found in a captive Chimpanzee. EV-A76, which is a widespread virus in humans, was identified in wild chimpanzees, thus suggesting its adaptation and parallel circulation in human and NHP populations in Cameroon. Interestingly, some EVs harbored by wild NHP were genetically distinct from all existing types and were thus assigned as new types. One chimpanzee-derived virus was tentatively assigned as EV-J121 in the EV-J species. In addition, two EVs from wild monkeys provisionally registered as EV-122 and EV-123 were found to belong to a candidate new species. Overall, this study indicates that the genetic diversity of EVs among NHP is more important than previously known and could be the source of future new emerging human viral diseases.

  14. Water availability and demand in West Africa in the 21st century: impacts of climate change and population growth

    Science.gov (United States)

    Wisser, Dominik; Oyerinde, Ganiyu; Ibrahim, Moussa; Ibrahim, Boubacar

    2014-05-01

    The countries in West Africa are highly dependent on rainfed agriculture. Changes in the magnitude and timing of precipitation will affect the agricultural output and the economies as a whole. Irrigation is increasingly being considered an important adaptation option to help improve food security of the population that is expected to double in less than 50 years. West Africa is one of the regions where general circulation models (GCM) show the highest disagreements in the direction of future trends of precipitation, making assessments of water availability and the potential for irrigation a difficult task. We use output from a set of dynamically downscaled climate data sets from regional climate modes (RCM) from the CORDEX CMIP5 collection to drive WBMplus, a macroscale hydrological model and simultaneously calculate water demand (livestock, domestic, and irrigation) and availability for a set of land use, and socio economic scenarios around the 2050's for river basins in the ten countries participating in the West African Science Service Center on Climate Change and Adapted Land Use (WASCAL) project. Contrary to earlier results from GCMs, the set of RCMs suggest a consistent increase (~5-10%) in annual precipitation for a majority of the land area in West Africa that translates to slight increases in river flow under natural conditions for most river basins and a opportunities for increasing irrigation during the dry season. However, water demand is projected to more than double for livestock and domestic needs as a result of population growth. Demand for irrigation will rise sharply if irrigation is expanded from the current area (representing less than 3% of all croplands in the region), closer to its potential which is multiple times higher than the existing area. The pressures on water resources in the region will therefore be dominated by pressures arising from increased demand rather than changes in the availability of water and can potentially lead to

  15. A systematic assessment of the current capacity to act in nutrition in West Africa: cross-country similarities and differences

    Directory of Open Access Journals (Sweden)

    Roger Sodjinou

    2014-07-01

    Full Text Available Background: Although it is widely accepted that lack of capacity is one of the barriers to scaling up nutrition in West Africa, there is a paucity of information about what capacities exist and the capacities that need to be developed to accelerate progress toward improved nutrition outcomes in the region. Objective: To systematically assess the current capacity to act in nutrition in the West Africa region and explore cross-country similarities and differences. Design: Data were collected from 13 West African countries through interviews with government officials, key development partners, tertiary-level training institutions, and health professional schools. The assessment was based on a conceptual framework of four interdependent levels (tools; skills; staff and infrastructure; and structures, systems and roles. In each of the surveyed countries, we assessed capacity assets and gaps at individual, organizational, and systemic levels. Results: Important similarities and differences in capacity assets and gaps emerged across all the surveyed countries. There was strong momentum to improve nutrition in nearly all the surveyed countries. Most of the countries had a set of policies on nutrition in place and had set up multisectoral, multi-stakeholder platforms to coordinate nutrition activities, although much remained to be done to improve the effectiveness of these platforms. Many initiatives aimed to reduce undernutrition were ongoing in the region, but there did not seem to be clear coordination between them. Insufficient financial resources to implement nutrition activities were a major problem in all countries. The bulk of financial allocations for nutrition was provided by development partners, even though some countries, such as Niger, Nigeria, and Senegal, had a national budget line for nutrition. Sporadic stock-outs of nutrition supplies were reported in most of the countries as a result of a weak logistic and supply chain system. They

  16. Aid and trade for livestock development and food security in West Africa

    NARCIS (Netherlands)

    Lee, van der J.; Schiere, J.B.; Bosma, R.H.; Olde, de E.; Bol, S.; Cornelissen, J.M.R.

    2014-01-01

    Veehouderij is in West Afrika van oudsher erg belangrijk. Het kent vele vormen en dient veel doelen, die vooral verschuiven van noord naar zuid. Deze analyse van de West Afrikaanse veehouderij is een quickscan geschreven door Wageningen UR Livestock Research en La Ventana consulting. Zij dient met n

  17. Computers, the Internet and medical education in Africa.

    Science.gov (United States)

    Williams, Christopher D; Pitchforth, Emma L; O'Callaghan, Christopher

    2010-05-01

    OBJECTIVES This study aimed to explore the use of information and communications technology (ICT) in undergraduate medical education in developing countries. METHODS Educators (deans and heads of medical education) in English-speaking countries across Africa were sent a questionnaire to establish the current state of ICT at medical schools. Non-respondents were contacted firstly by e-mail, subsequently by two postal mailings at 3-month intervals, and finally by telephone. Main outcome measures included cross-sectional data about the availability of computers, specifications, Internet connection speeds, use of ICT by students, and teaching of ICT and computerised research skills, presented by country or region. RESULTS The mean computer : student ratio was 0.123. Internet speeds were rated as 'slow' or 'very slow' on a 5-point Likert scale by 25.0% of respondents overall, but by 58.3% in East Africa and 33.3% in West Africa (including Cameroon). Mean estimates showed that campus computers more commonly supported CD-ROM (91.4%) and sound (87.3%) than DVD-ROM (48.1%) and Internet (72.5%). The teaching of ICT and computerised research skills, and the use of computers by medical students for research, assignments and personal projects were common. CONCLUSIONS It is clear that ICT infrastructure in Africa lags behind that in other regions. Poor download speeds limit the potential of Internet resources (especially videos, sound and other large downloads) to benefit students, particularly in East and West (including Cameroon) Africa. CD-ROM capability is more widely available, but has not yet gained momentum as a means of distributing materials. Despite infrastructure limitations, ICT is already being used and there is enthusiasm for developing this further. Priority should be given to developing partnerships to improve ICT infrastructure and maximise the potential of existing technology.

  18. Henneguya mbakaouensis sp. nov., Myxobolus nounensis sp. nov. and M. hydrocyni Kostoingue & Toguebaye, 1994, Myxosporea (Myxozoa parasites of centropomidae, Cichlidae and Characidae (Teleosts of the Sanaga basin in Cameroon (Central Africa

    Directory of Open Access Journals (Sweden)

    Fomena A.

    2000-09-01

    Full Text Available The study of 102 teleost freshwater fishes of Sanaga basin in Cameroon revealed the presence of three myxosporean species, among which two were new. Host fishes were of three families: Centropomidae, Cichlidae and Characidae. New species were identified as Henneguya mbakaouensis sp. nov., a gill parasite of Lates niloticus and Myxobolus nounensis sp. nov. found in the kidney and spleen of Sarotherodon galilaeus and Tilapia mariae. Myxobolus hydrocyni Kostoïngue & Toguebaye, 1994, previously described in Chad, was also found in Cameroon; complementary informations were given on that parasite which seemed to be specific to its host.

  19. The ancient tropical rainforest tree Symphonia globulifera L. f. (Clusiaceae) was not restricted to postulated Pleistocene refugia in Atlantic Equatorial Africa.

    Science.gov (United States)

    Budde, K B; González-Martínez, S C; Hardy, O J; Heuertz, M

    2013-07-01

    Understanding the history of forests and their species' demographic responses to past disturbances is important for predicting impacts of future environmental changes. Tropical rainforests of the Guineo-Congolian region in Central Africa are believed to have survived the Pleistocene glacial periods in a few major refugia, essentially centred on mountainous regions close to the Atlantic Ocean. We tested this hypothesis by investigating the phylogeographic structure of a widespread, ancient rainforest tree species, Symphonia globulifera L. f. (Clusiaceae), using plastid DNA sequences (chloroplast DNA [cpDNA], psbA-trnH intergenic spacer) and nuclear microsatellites (simple sequence repeats, SSRs). SSRs identified four gene pools located in Benin, West Cameroon, South Cameroon and Gabon, and São Tomé. This structure was also apparent at cpDNA. Approximate Bayesian Computation detected recent bottlenecks approximately dated to the last glacial maximum in Benin, West Cameroon and São Tomé, and an older bottleneck in South Cameroon and Gabon, suggesting a genetic effect of Pleistocene cycles of forest contraction. CpDNA haplotype distribution indicated wide-ranging long-term persistence of S. globulifera both inside and outside of postulated forest refugia. Pollen flow was four times greater than that of seed in South Cameroon and Gabon, which probably enabled rapid population recovery after bottlenecks. Furthermore, our study suggested ecotypic differentiation-coastal or swamp vs terra firme-in S. globulifera. Comparison with other tree phylogeographic studies in Central Africa highlighted the relevance of species-specific responses to environmental change in forest trees.

  20. Phylogenetic and pathotypic characterization of newcastle disease viruses circulating in west Africa and efficacy of a current vaccine.

    Science.gov (United States)

    Samuel, Arthur; Nayak, Baibaswata; Paldurai, Anandan; Xiao, Sa; Aplogan, Gilbert L; Awoume, Kodzo A; Webby, Richard J; Ducatez, Mariette F; Collins, Peter L; Samal, Siba K

    2013-03-01

    Newcastle disease (ND) is a deadly avian disease worldwide. In Africa, ND is enzootic and causes large economic losses, but little is known about the Newcastle disease virus (NDV) strains circulating in African countries. In this study, 27 NDV isolates collected from apparently healthy chickens in live-bird markets of the West African countries Benin and Togo in 2009 were characterized. All isolates had polybasic fusion (F)-protein cleavage sites and were shown to be highly virulent in standard pathogenicity assays. Infection of 2-week-old chickens with two of the isolates resulted in 100% mortality within 4 days. Phylogenetic analysis of the 27 isolates based on a partial F-protein gene sequence identified three clusters: one containing all the isolates from Togo and one from Benin (cluster 2), one containing most isolates from Benin (cluster 3), and an outlier isolate from Benin (cluster 1). All the three clusters are related to genotype VII strains of NDV. In addition, the cluster of viruses from Togo contained a recently identified 6-nucleotide insert between the hemagglutinin-neuraminidase (HN) and large polymerase (L) genes in a complete genome of an NDV isolate from this geographical region. Multiple strains that include this novel element suggest local emergence of a new genome length class. These results reveal genetic diversity within and among local NDV populations in Africa. Sequence analysis showed that the F and HN proteins of six West African isolates share 83.2 to 86.6% and 86.5 to 87.9% identities, respectively, with vaccine strain LaSota, indicative of considerable diversity. A vaccine efficacy study showed that the LaSota vaccine protected birds from morbidity and mortality but did not prevent shedding of West African challenge viruses.

  1. A new subtype (subgenotype) Ac (A3) of hepatitis B virus and recombination between genotypes A and E in Cameroon.

    Science.gov (United States)

    Kurbanov, Fuat; Tanaka, Yasuhito; Fujiwara, Kei; Sugauchi, Fuminaka; Mbanya, Dora; Zekeng, Leopold; Ndembi, Nicaise; Ngansop, Charlotte; Kaptue, Lazare; Miura, Tomoyuki; Ido, Eiji; Hayami, Masanori; Ichimura, Hiroshi; Mizokami, Masashi

    2005-07-01

    Blood samples (n=544) from two different populations (Pygmies and Bantus) in Cameroon, West Africa, were analysed. Serological tests indicated that the anti-hepatitis C virus (HCV) prevalence in Bantus (20.3 %) was higher than that in Pygmies (2.3 %, PHBV) serological markers was equally high in both populations: in total, 9.4, 17.3 and 86.8 % for HBsAg, anti-HBs and anti-HBc, respectively. HBV genotype A (HBV/A) and HBV/E were predominant (43.5 % each) in both populations, and HBV/D was found in a minority (13 %). The preS/S region was sequenced in nine cases (five HBV/A and four HBV/E) and the complete genome in six cases (four HBV/A and two HBV/E). Subsequent phylogenetic analysis revealed that the HBV/A strains were distinct from the subtypes (subgenotypes) described previously, Ae (A2) and Aa (A1), and in the preS/S region they clustered with previously reported sequences from Cameroon. Based on the nucleotide difference from Aa (A1) and Ae (A2), more than 4 % in the complete genome, the Cameroonian strains were suggested to represent a new subtype (subgenotype), designated HBV/Ac (A3). A high (3.9 %) nucleotide divergence in HBV/Ac (A3) strains suggested that the subtype (subgenotype) has a long natural history in the population of Cameroon. One of the HBV/Ac (A3) strains was found to be a recombinant with an HBV/E-specific sequence in the polymerase reverse transcriptase domain. Further cohort studies will be required to assess detailed epidemiological, virological and clinical characteristics of HBV/Ac (A3), as well as its recombinant form.

  2. Nutrients, technological properties and genetic relationships among twenty cowpea landraces cultivated in West Africa

    NARCIS (Netherlands)

    Madode, Y.E.E.; Linnemann, A.R.; Nout, M.J.R.; Vosman, B.J.; Hounhouigan, D.J.; Boekel, van T.

    2012-01-01

    The genetic relationships among twenty phenotypically different cowpea landraces were unravelled regarding their suitability for preparing West African dishes. Amplified fragment length polymorphism classified unpigmented landraces (UPs) as highly similar (65%, one cluster), contrary to pigmented la

  3. Masked millennial-scale climate variations in South West Africa during the last glaciation

    Directory of Open Access Journals (Sweden)

    I. Hessler

    2012-04-01

    Full Text Available To address the connection between tropical African vegetation development and high-latitude climate change we present a high-resolution pollen record from ODP Site 1078 (off Angola covering the period 50–10 ka BP. Although several tropical African vegetation and climate reconstructions indicate an impact of Heinrich Stadials (HSs in Southern Hemisphere Africa, our vegetation record shows no response. Model simulations conducted with an Earth System Model of Intermediate Complexity including a dynamical vegetation component provide one possible explanation. Because both precipitation and evaporation increased during HSs and their effects nearly cancelled each other, there was a negligible change in moisture supply. Consequently, the resulting climatic response to HSs might have been too weak to noticeably affect the vegetation composition in the study area. Our results also show that the response to HSs in southern tropical Africa neither equals nor mirrors the response to abrupt climate change in northern Africa.

  4. AMMA-CATCH a Hydrological, Meteorological and Ecological Long Term Observatory on West Africa : Some Recent Results

    Science.gov (United States)

    Galle, S.; Grippa, M.; Peugeot, C.; Bouzou Moussa, I.; Cappelaere, B.; Demarty, J.; Mougin, E.; Lebel, T.; Chaffard, V.

    2015-12-01

    AMMA-CATCH is a multi-scale observation system dedicated to long-term monitoring of the water cycle, the vegetation dynamics and their interaction with climate and water resources in West Africa. In the context of the global change, long-term observations are required to i) gain understanding in eco-hydrological processes over this highly contrasted region, ii) help their representation in Earth System Models, and iii) detect trends and infer their impacts on water resources and living conditions. It is made of three meso-scale sites (~ 1°x1°) in Mali, Niger and Benin, extending along the West African eco-climatic gradient. Within this regional window (5° by 9°), each of the three sites comprises a multi-scale set-up which helps documenting the components of the hydrologic budget and the evolutions of the surface conditions over a range of time scales: raingages, piezometers, river discharge stations, soil moisture and temperature profiles, turbulent fluxes measurements, LAI/biomass monitoring. This observation system has been continuously generating coherent datasets for 10 to 25 years depending on the datasets. It is jointly operated by French and African (Mali, Niger and Benin) research institutions. The data-base is available to the community through the website (www.amma-catch.org). AMMA-CATCH is a member of the French critical zone observatory network "Réseau des Bassins Versants", (RBV). AMMA-CATH participates to several global or regional observation networks, such as FluxNet, CarboAfrica, International Soil Moisture Networks (ISMN) and to calibration/validation campaigns for satellite missions such as SMOS (CNES, ESA), MEGHA-TROPIQUES (France/India) or SWAP(NASA). AMMA-CATCH fills a gap over a region, West Africa, where environmental data are largely lacking, and thus, it can usefully contribute to the international networking effort for environmental monitoring and research. Recent results on regional evolution of land cover, rainfall intensity and

  5. Biomass Residues from Agriculture and Potential Contribution towards Modern Energy Supply in West Africa

    DEFF Research Database (Denmark)

    Ackom, Emmanuel

    2016-01-01

    Access to modern energy services especially in developing countries is an urgent issue. Globally, 1.3 billion people do not have access to modern energy and the services associated with it. Sub-Saharan Africa is one of the regions have profound lack of modern energy access. The objective of this ......Access to modern energy services especially in developing countries is an urgent issue. Globally, 1.3 billion people do not have access to modern energy and the services associated with it. Sub-Saharan Africa is one of the regions have profound lack of modern energy access. The objective...... prospect for improved quality of life, poverty alleviation and sustainable development....

  6. Application of model studies for quality control of bottom pressure based GLOSS sea level gauge at Takoradi Harbour (Ghana, West Africa)

    Digital Repository Service at National Institute of Oceanography (India)

    Joseph, A.; Mehra, P.; Desai, R.G.P.; Dotse, J.; Odammetey, J.T.; Nkebi, E.K.; VijayKumar, K.; Prabhudesai, S.

    Application of Model Studies for Quality Control of Bottom Pressure Based GLOSS Sea Level Gauge at Takoradi Harbour (Ghana, West Africa) Antony Joseph 1 , Prakash Mehra 1 , R. G. Prabhudesai 1 , Jean Dotse 2 , Joseph T. Odammetey 2 , Emmanuel K. Nkebi 2...

  7. If We Don’t, Who Will? The Employment of the United States Army to Combat Potential Pandemic Outbreaks in West Africa

    Science.gov (United States)

    2015-06-12

    pandemic outbreak in West Africa, requires consideration of the existing literature. Next, the secondary research questions will be researched and......Wolf explains, “It is generally considered unfair or unjust to blame someone for failing to do what she could not reasonably be expected to know she

  8. An introduction to the SCOUT-AMMA stratospheric aircraft, balloons and sondes campaign in West Africa, August 2006 : rationale and roadmap

    NARCIS (Netherlands)

    Cairo, F.; Pommereau, J. P.; Law, K. S.; Schlager, H.; Garnier, A.; Fierli, F.; Ern, M.; Streibel, M.; Arabas, S.; Borrmann, S.; Berthelier, J. J.; Blom, C.; Christensen, T.; D'Amato, F.; Di Donfrancesco, G.; Deshler, T.; Diedhiou, A.; Durry, G.; Engelsen, O.; Goutail, F.; Harris, N. R. P.; Kerstel, E. R. T.; Khaykin, S.; Konopka, P.; Kylling, A.; Larsen, N.; Lebel, T.; Liu, X.; MacKenzie, A. R.; Nielsen, J.; Oulanowski, A.; Parker, D. J.; Pelon, J.; Polcher, J.; Pyle, J. A.; Ravegnani, F.; Riviere, E. D.; Robinson, A. D.; Rockmann, T.; Schiller, C.; Simoes, F.; Stefanutti, L.; Stroh, F.; Some, L.; Siegmund, P.; Sitnikov, N.; Vernier, J. P.; Volk, C. M.; Voigt, C.; von Hobe, M.; Viciani, S.; Yushkov, V.

    2010-01-01

    A multi-platform field measurement campaign involving aircraft and balloons took place over West Africa between 26 July and 25 August 2006, in the frame of the concomitant AMMA Special Observing Period and SCOUT-O-3 African tropical activities. Specifically aiming at sampling the upper troposphere a

  9. Impact of ivermectin on onchocerciasis transmission: Assessing the empirical evidence that repeated ivermectin mass treatments may lead to elimination/eradication in West-Africa

    NARCIS (Netherlands)

    G.J.J.M. Borsboom (Gerard); B.A. Boatin (Boakye); N.J.D. Nagelkerke (Nico); H. Agoua (Hyacinthe); K.L.B. Akpoboua (Komlan); E.W. Soumbey Alley (E. William); Y. Bissan (Yeriba); A. Renz (Anna); L. Yameogo (Laurent); J.H.F. Remme (Jan); J.D.F. Habbema (Dik)

    2003-01-01

    markdownabstract__Background:__ The Onchocerciasis Control Program (OCP) in West Africa has been closed down at the end of 2002. All subsequent control will be transferred to the participating countries and will almost entirely be based on periodic mass treatment with ivermectin. This makes the ques

  10. Exploring the diversity of urban and peri-urban agricultural systems in Sudano-Sahelian West Africa: An attempt towards a regional typology

    NARCIS (Netherlands)

    Dossa, L.C.; Abdulkadir, A.; Amadou, H.; Sangare, S.; Schlecht, E.

    2011-01-01

    Developing appropriate and innovative technologies and policies to respond to the challenges that urban and peri-urban agriculture (UPA) faces in West Africa requires a better understanding of the existing production systems. Although there is an increasing recognition of the importance of UPA in th

  11. Climate scenarios for semi-arid and sub-humid regions. A comparison of climate scenarios for the dryland regions, in West Africa from 1990 to 2050

    NARCIS (Netherlands)

    van den Born GJ; Schaeffer M; Leemans R; NOP

    2001-01-01

    The identification of climate scenarios for dryland areas in Sub-Saharan West Africa is part of a project to assess the impact of climate change on water availability, agriculture and food security in drylands (ICCD-project). The project is financed by Netherlands Research Programme on Global Air P

  12. Region-wide assessment of the capacity for human nutrition training in West Africa: current situation,challenges, and way forward

    NARCIS (Netherlands)

    Sodjinou, R.; Fanou, N.; Deart, L.; Pepping, F.

    2014-01-01

    Background: There is a dearth of information on existing nutrition training programs in West Africa. A preliminary step in the process of developing a comprehensive framework to strengthen human capacity for nutrition is to conduct an inventory of existing training programs. Objective: This study wa

  13. Bibliographic analysis of scientific research on selected topics in public health nutrition in West Africa: Review of articles published from 1998 to 2008.

    Science.gov (United States)

    Aaron, Grant J; Wilson, Shelby E; Brown, Kenneth H

    2010-01-01

    Few countries in West Africa have the capacity for carrying out advanced training in nutrition and public health. To provide additional information on current regional applied nutrition research capacity and productivity, we analysed peer-reviewed articles on key public health nutrition topics that were published from 1998 to 2008. Using MEDLINE/PubMed, the following terms were searched: 'breast feeding', 'infant nutrition physiology' (comprising complementary feeding and weaning), 'protein energy malnutrition', 'nutrition and infection', 'vitamin A', 'iodine', 'zinc' and 'overweight', each linked with the term 'Western Africa'. In total, 412 unique articles (37±6 articles per year) were identified. Most research focused on infant and young child feeding practices, selected micronutrient deficiencies, and the emerging problem of overweight and obesity. The primary author of nearly half (46%) the publications was located in an institution outside of West Africa. Most articles were published in English (90%), and nearly half of all articles (41%) were cross-sectional studies. Our findings indicate that few peer-reviewed research studies are being published on key public health topics in the West African region, considering the magnitude of nutrition problems in this region. New approaches are needed to encourage and support research capacity and output in West Africa.

  14. Implementation of Information Communication Technology in the Teaching/Learning Process for Sustainable Development of Adults in West Africa Sub Sahara Region

    Science.gov (United States)

    Nwobi, Anthonia; Ngozi, Ugwuoke; Rufina, Nwachukwu; Ogbonnaya, Kingsley A.

    2016-01-01

    This study examines the implementation of information technology in the teaching/learning process for sustainable development of adults in West Africa Sub Sahara Region (WASSR). Three research questions and two hypotheses guided the study. The population for the study was 3071 participants and instructors drawn from 10 education centres that were…

  15. First record of a white rough-toothed dolphin (Steno bredanensis) off West Africa including notes on rough-toothed dolphin surface behaviour

    NARCIS (Netherlands)

    Boer, de M.N.

    2010-01-01

    In June 2009, a white rough-toothed dolphin (Steno bredanensis) calf was photographed in a group of at least 50 dolphins in the southern Gulf of Guinea, 95 nauticol miles off the Gabon coast (01°45'S 007°29'E), West Africa. Reports of unusually pigmented cetaceans are infrequent and this record repr

  16. Characterization of African Bush Mango trees with emphasis on the differences between sweet and bitter trees in the Dahomey Gap (West Africa)

    NARCIS (Netherlands)

    Vihotogbe, R.

    2012-01-01

     African bush mango trees (ABMTs) are economically the most important species within the family of Irvingiaceae. They are priority trees producing non-timber forest products (NTFPs) and widely distributed in the humid lowland forests of West and Central Africa. To boost their production and dev

  17. Development of reference transcriptomes for the major insect pests of cowpea: a toolbox for insect pest management approaches in West Africa

    Science.gov (United States)

    Cowpea crops are widely cultivated and a major nutritional source of protein for indigenous human populations in West Africa. Annual yields and longevity of grain storage is greatly reduced by feeding damage caused by a complex of insect pests that include Anoplocnemis curvipes, Aphis craccivora, Cl...

  18. Financing Higher Education in Francophone West Africa. An EDI Policy Seminar Report, Number 12.

    Science.gov (United States)

    Ransom, Angela

    Meetings were held in Senegal in 1985, in Cote d'Ivoire in 1986, and in Zimbabwe in 1987, concerning the current state of higher education finance in Africa, the structure of unit costs, and the role of development assistance agencies and other sources of financial support. Reports are presented concerning the macroeconomic perspective, internal…

  19. Effectiveness of Alternative Extension Methods through Radio Broadcasting in West Africa

    Science.gov (United States)

    Moussa, Bokar; Otoo, Miriam; Fulton, Joan; Lowenberg-DeBoer, James

    2011-01-01

    There is an urgent need to quantify which extension methods are most effective in Africa. The objective of this study was to determine the impact of alternative extension methods on adoption of the triple bagging cowpea storage technology in Niger and Burkina Faso. This study was designed as a quasi-experiment with two alternative extension…

  20. Geostatistical model-based estimates of schistosomiasis prevalence among individuals aged = 20 years in West Africa

    DEFF Research Database (Denmark)

    Schur, Nadine; Hürlimann, Eveline; Garba, Amadou;

    2011-01-01

    Schistosomiasis is a water-based disease that is believed to affect over 200 million people with an estimated 97% of the infections concentrated in Africa. However, these statistics are largely based on population re-adjusted data originally published by Utroska and colleagues more than 20 years...

  1. Kyllinga cataphyllata (Cyperaceae), a new species from the highlands of West and Central Africa

    NARCIS (Netherlands)

    Huygh, W.; Schouppe, D.; Larridon, I.; Simpson, D.A.; Goetghebeur, P.

    2010-01-01

    Kyllinga cataphyllata, a new species of Cyperaceae from the highlands of Western and Central Africa, is described and illustrated. This new species is easy recognized by the ascending rhizome densely covered by large cataphylls. The head-like inflorescence consisting of a single spike with spikelets

  2. Long-term effects of conservation soil management in Saria, Burkina Faso, West Africa

    NARCIS (Netherlands)

    Zacharie, Z.

    2011-01-01

    The negative degradation spiral that currently leads to deteriorating soil properties in African drylands is a serious problem that limits food production and threatensthe livelihoods of the people. Nutrient depletion and water and wind erosion are the main factors in soil degradation in Africa. Thi

  3. Ebola virus disease: a highly fatal infectious disease reemerging in West Africa.

    Science.gov (United States)

    To, Kelvin K W; Chan, Jasper F W; Tsang, Alan K L; Cheng, Vincent C C; Yuen, Kwok-Yung

    2015-02-01

    Ebolavirus can cause a highly fatal and panic-generating human disease which may jump from bats to other mammals and human. High viral loads in body fluids allow efficient transmission by contact. Lack of effective antivirals, vaccines and public health infrastructures in parts of Africa make it difficult to health workers to contain the outbreak.

  4. Social and Cutural Aspects of HIV and AIDS in West Africa

    DEFF Research Database (Denmark)

    Samuelsen, Helle; Ostergaard, Lise Rosendal; Norgaard, Ole

    2012-01-01

    With the increasing focus on the role of social aspects of the HIV epidemic in sub-Saharan Africa, the need for an overview of existing research dealing with such issues has become more urgent. The objective of this article is to provide a thematic overview of existing qualitative research on HIV...

  5. Integrated water pollution assessment of the Ebrié Lagoon, Ivory Coast, West Africa

    NARCIS (Netherlands)

    Scheren, P.A.G.M.; Kroeze, C.; Jansen, F.J.J.G.; Hordijk, L.; Ptasinski, K.J.

    2004-01-01

    An environmental pollution assessment of the Ebrie lagoon, the largest coastal ecosystem in Western Africa, was executed by applying the Driving force-Pressure-State-Impacts-Response (DPSIR) framework. The domestic and industrial activities in Abidjan and agricultural activities in the wider catchme

  6. The Use of Lactic Acid Bacteria Starter Cultures during the Processing of Fermented Cereal-based Foods in West Africa: A Review.

    Science.gov (United States)

    Soro-Yao, Amenan Anastasie; Brou, Kouakou; Amani, Georges; Thonart, Philippe; Djè, Koffi Marcelin

    2014-12-01

    Lactic acid bacteria (LAB) are the primary microorganisms used to ferment maize-, sorghum- or millet-based foods that are processed in West Africa. Fermentation contributes to desirable changes in taste, flavour, acidity, digestibility and texture in gruels (ogi, baca, dalaki), doughs (agidi, banku, komé) or steam-cooked granulated products (arraw, ciacry, dégué). Similar to other fermented cereal foods that are available in Africa, these products suffer from inconsistent quality. The use of LAB starter cultures during cereal dough fermentation is a subject of increasing interest in efforts to standardise this step and guaranty product uniformity. However, their use by small-scale processing units or small agro-food industrial enterprises is still limited. This review aims to illustrate and discuss major issues that influence the use of LAB starter cultures during the processing of fermented cereal foods in West Africa.

  7. Ectoparasites of dogs belonging to people in resource-poor communities in North West Province, South Africa

    Directory of Open Access Journals (Sweden)

    N.R. Bryson

    2000-07-01

    Full Text Available A total of 344 dogs belonging to people in resource-poor communities in North West Province, South Africa, was examined for ectoparasites, and all visible arthropods were collected from the left side of each dog. By doubling these numbers it was estimated that the dogs harboured 14 724 ixodid ticks, belonging to 6 species, 1028 fleas, belonging to 2 species, and 26 lice. Haemaphysalis leachi accounted for 420 and Rhipicephalus sanguineus for 14 226 of the ticks. Pure infestations of H. leachi were present on 14 dogs and of R. sanguineus on 172 dogs. Small numbers of Amblyomma hebraeum, R. appendiculatus, R. evertsi evertsi and R. simus were also collected. The predominance of R. sanguineus accounts for the high prevalence of canine ehrlichiosis (Ehrlichia canis within the survey region, compared to canine babesiosis (Babesia canis, which is transmitted by H. leachi, and is a much rarer disease.

  8. High spatial resolution mapping of malaria transmission risk in the Gambia, west Africa, using LANDSAT TM satellite imagery.

    Science.gov (United States)

    Bøgh, Claus; Lindsay, Steven W; Clarke, Siân E; Dean, Andy; Jawara, Musa; Pinder, Margaret; Thomas, Christopher J

    2007-05-01

    Understanding local variability in malaria transmission risk is critically important when designing intervention or vaccine trials. Using a combination of field data, satellite image analysis, and GIS modeling, we developed a high-resolution map of malaria entomological inoculation rates (EIR) in The Gambia, West Africa. The analyses are based on the variation in exposure to malaria parasites experienced in 48 villages in 1996 and 21 villages in 1997. The entomological inoculation rate (EIR) varied from 0 to 166 infective bites per person per rainy season. Detailed field surveys identified the major Anopheles gambiae s.l. breeding habitats. These habitats were mapped by classification of a LANDSAT TM satellite image with an overall accuracy of 85%. Village EIRs decreased as a power function based on the breeding areas size and proximity. We use this relationship and the breeding habitats to map the variation in EIR over the entire 2500-km(2) study area.

  9. Observations of ultrafine particle nucleation events in the tropical UT/LS over West Africa and Brazil

    Science.gov (United States)

    Borrmann, S.; Curtius, J.; Kunkel, D.; Weigel, R.; Vicani, S.; Schiller, C.; Ulanovski, A.; Ravegnani, F.; Cairo, F.; Law, K. A.

    2009-04-01

    New particle formation by gas to particle conversion in the tropical upper troposphere and lower stratosphere (UT/LS) may be a major source of aerosols for origin and maintenance of the global stratospheric Junge aerosol layer. Once created in the tropical upper troposphere these ultrafine particles can be carried aloft towards the tropopause by the -radiatively driven- slowly rising air, and subsequently enter the Brewer-Dobson circulation for global distribution within the stratosphere. During the TROCCINOX (2005) and AMMA-SCOUT (2006) campaigns in South America (Brazil) and West-Africa (Burkina Faso) the Russian M-55 high altitude research aircraft "Geophysica" performed in-situ measurements of trace gases and aerosols in the tropical UT/LS. By means of the four channel COPAS condensation particle counting system total ultrafine particle number concentrations were measured for ambient aerosol particles with size diameters larger than 6 nm, 10 nm, and 14 nm, respectively. The fourth channel also had a lower "cut-off" diameter of 10 nm, but here the sample air was heated to 250 °C prior to the particle detection. Thus, this channel delivered the number of non volatile particles providing information on the fraction of particles NOT consisting of binary sulfuric acid/water solutions. During both campaigns cloud free air masses were encountered between 12 and 14 km altitude with ultrafine particle concentrations as high as 8000 to 10000 particles per cm³. Based on the difference of the count results from the channels with 6 nm and 14 nm cut-off diameters it can be concluded that the particles were freshly formed in-situ during so called nucleation events. Covering flight path lengths of roughly 300 km over West-Africa and 600 km over Brazil these areas with enhanced particle concentrations are of significant scale. For the data observed over Brazil oxidation of ground released SO2 to H2SO4 while being lifted -possibly supported by ion induced nucleation- is a

  10. Embargo on Lion Hunting Trophies from West Africa: An Effective Measure or a Threat to Lion Conservation?

    Directory of Open Access Journals (Sweden)

    Philippe Bouché

    Full Text Available The W-Arly-Pendjari (WAP ecosystem, shared among Benin, Burkina Faso and Niger, represents the last lion stronghold of West Africa. To assess the impact of trophy hunting on lion populations in hunting areas of the WAP, we analyzed trends in harvest rates from 1999 to 2014. We also investigated whether the hunting areas with higher initial hunting intensity experienced steeper declines in lion harvest between 1999 and 2014, and whether lion densities in hunting areas were lower than in national parks. Lion harvest rate remained overall constant in the WAP. At initial hunting intensities below 1.5 lions/1000km2, most hunting areas experienced an increase in lion harvest rate, although that increase was of lower magnitude for hunting areas with higher initial hunting intensity. The proportion of hunting areas that experienced a decline in lion harvest rate increased at initial hunting intensities above 1.5 lions/1000km2. In 2014, the lion population of the WAP was estimated with a spoor count at 418 (230-648 adults and sub-adult individuals, comparable to the 311 (123-498 individuals estimated in the previous 2012 spoor survey. We found no significant lion spoor density differences between national parks and hunting areas. Hunting areas with higher mean harvest rates did not have lower lion densities. The ratio of large adult males, females and sub-adults was similar between the national parks and the hunting areas. These results suggested that the lion population was not significantly affected by hunting in the WAP. We concluded that a quota of 1 lion/1000km2 would be sustainable for the WAP. Based on our results, an import embargo on lion trophies from the WAP would not be justified. It could ruin the incentive of local actors to conserve lions in hunting areas, and lead to a drastic reduction of lion range in West Africa.

  11. The spatial genetic differentiation of the legume pod borer, Maruca vitrata F. (Lepidoptera: Crambidae) populations in West Africa.

    Science.gov (United States)

    Agunbiade, T A; Coates, B S; Kim, K S; Forgacs, D; Margam, V M; Murdock, L L; Ba, M N; Binso-Dabire, C L; Baoua, I; Ishiyaku, M F; Tamò, M; Pittendrigh, B R

    2012-10-01

    The legume pod borer, Maruca vitrata, is an endemic insect pest that causes significant yield loss to the cowpea crop in West Africa. The application of population genetic tools is important in the management of insect pests but such data on M. vitrata is lacking. We applied a set of six microsatellite markers to assess the population structure of M. vitrata collected at five sites from Burkina Faso, Niger and Nigeria. Observed polymorphisms ranged from one (marker 3393) to eight (marker 32008) alleles per locus. Observed and expected heterozygosities ranged from 0.0 to 0.8 and 0.0 to 0.6, respectively. Three of the loci in samples from Nigeria and Burkina Faso deviated significantly from Hardy-Weinberg Equilibrium (HWE), whereas no loci deviated significantly in samples from Niger. Analysis of molecular variance (AMOVA) indicated that 67.3% level of the genetic variation was within individuals compared to 17.3% among populations. A global estimate of F ST=0.1 (ENA corrected F ST=0.1) was significant (P⩽0.05) and corroborated by pairwise F ST values that were significant among all possible comparisons. A significant correlation was predicted between genetic divergence and geographic distance between subpopulations (R2=0.6, P=0.04), and cluster analysis by the program STRUCTURE predicted that co-ancestry of genotypes were indicative of three distinct populations. The spatial genetic variance among M. vitrata in West Africa may be due to limited gene flow, south-north seasonal movement pattern or other reproductive barriers. This information is important for the cultural, chemical and biological control strategies for managing M. vitrata.

  12. Prescribing practice for malaria following introduction of artemether-lumefantrine in an urban area with declining endemicity in West Africa

    Directory of Open Access Journals (Sweden)

    Conway David J

    2010-06-01

    Full Text Available Abstract Background The decline in malaria coinciding with the introduction of newer, costly anti-malarials has prompted studies into the overtreatment for malaria mostly in East Africa. The study presented here describes prescribing practices for malaria at health facilities in a West African country. Methods Cross-sectional surveys were carried out in two urban Gambian primary health facilities (PHFs during and outside the malaria transmission season. Facilities were comparable in terms of the staffing compliment and capability to perform slide microscopy. Patients treated for malaria were enrolled after consultations and blood smears collected and read at a reference laboratory. Slide reading results from the PHFs were compared to the reference readings and the proportion of cases treated but with a negative test result at the reference laboratory was determined. Results Slide requests were made for 33.2% (173 of those enrolled, being more frequent in children (0-15 yrs than adults during the wet season (p = 0.003. In the same period, requests were commoner in under-fives compared to older children (p = 0.022; however, a positive test result was 4.4 times more likely in the latter group (p = 0.010. Parasitaemia was confirmed for only 4.7% (10/215 and 12.5% (37/297 of patients in the dry and wet seasons, respectively. The negative predictive value of a PHF slide remained above 97% in both seasons. Conclusions The study provides evidence for considerable overtreatment for malaria in a West African setting comparable to reports from areas with similar low malaria transmission in East Africa. The data suggest that laboratory facilities may be under-used, and that adherence to negative PHF slide results could significantly reduce the degree of overtreatment. The "peak prevalence" in 5-15 year olds may reflect successful implementation of malaria control interventions in under-fives, but point out the need to extend such interventions to older

  13. Heterogeneity in District-Level Transmission of Ebola Virus Disease during the 2013-2015 Epidemic in West Africa.

    Directory of Open Access Journals (Sweden)

    Fabienne Krauer

    2016-07-01

    Full Text Available The Ebola virus disease (EVD epidemic in West Africa in 2013-2015 spread heterogeneously across the three hardest-hit countries Guinea, Liberia and Sierra Leone and the estimation of national transmission of EVD provides little information about local dynamics. To investigate district-level transmissibility of EVD, we applied a statistical modelling approach to estimate the basic reproduction number (R0 for each affected district and each country using weekly incident case numbers. We estimated growth rates during the early exponential phase of the outbreak using exponential regression of the case counts on the first eight weeks since onset. To take into account the heterogeneity between and within countries, we fitted a mixed effects model and calculated R0 based on the predicted individual growth rates and the reported serial interval distribution. At district level, R0 ranged from 0.36 (Dubréka to 1.72 (Beyla in Guinea, from 0.53 (Maryland to 3.37 (Margibi in Liberia and from 1.14 (Koinadugu to 2.73 (Western Rural in Sierra Leone. At national level, we estimated an R0 of 0.97 (95% CI 0.77-1.18 for Guinea, 1.26 (95% CI 0.98-1.55 for Liberia and 1.66 (95% CI 1.32-2.00 for Sierra Leone. Socio-demographic variables related to urbanisation such as high population density and high wealth index were found positively associated with R0 suggesting that the consequences of fast urban growth in West Africa may have contributed to the increased spread of EVD.

  14. Embargo on Lion Hunting Trophies from West Africa: An Effective Measure or a Threat to Lion Conservation?

    Science.gov (United States)

    Bouché, Philippe; Crosmary, William; Kafando, Pierre; Doamba, Benoit; Kidjo, Ferdinand Claude; Vermeulen, Cédric; Chardonnet, Philippe

    2016-01-01

    The W-Arly-Pendjari (WAP) ecosystem, shared among Benin, Burkina Faso and Niger, represents the last lion stronghold of West Africa. To assess the impact of trophy hunting on lion populations in hunting areas of the WAP, we analyzed trends in harvest rates from 1999 to 2014. We also investigated whether the hunting areas with higher initial hunting intensity experienced steeper declines in lion harvest between 1999 and 2014, and whether lion densities in hunting areas were lower than in national parks. Lion harvest rate remained overall constant in the WAP. At initial hunting intensities below 1.5 lions/1000km2, most hunting areas experienced an increase in lion harvest rate, although that increase was of lower magnitude for hunting areas with higher initial hunting intensity. The proportion of hunting areas that experienced a decline in lion harvest rate increased at initial hunting intensities above 1.5 lions/1000km2. In 2014, the lion population of the WAP was estimated with a spoor count at 418 (230-648) adults and sub-adult individuals, comparable to the 311 (123-498) individuals estimated in the previous 2012 spoor survey. We found no significant lion spoor density differences between national parks and hunting areas. Hunting areas with higher mean harvest rates did not have lower lion densities. The ratio of large adult males, females and sub-adults was similar between the national parks and the hunting areas. These results suggested that the lion population was not significantly affected by hunting in the WAP. We concluded that a quota of 1 lion/1000km2 would be sustainable for the WAP. Based on our results, an import embargo on lion trophies from the WAP would not be justified. It could ruin the incentive of local actors to conserve lions in hunting areas, and lead to a drastic reduction of lion range in West Africa.

  15. Social and cultural aspects of HIV and AIDS in West Africa: a narrative review of qualitative research.

    Science.gov (United States)

    Samuelsen, Helle; Norgaard, Ole; Ostergaard, Lise Rosendal

    2012-01-01

    With the increasing focus on the role of social aspects of the HIV epidemic in sub-Saharan Africa, the need for an overview of existing research dealing with such issues has become more urgent. The objective of this article is to provide a thematic overview of existing qualitative research on HIV and AIDS in the West African region and to analyze the main research findings in order to identify possible gaps and recommend new research themes to inform future research-based interventions. The analysis is based on a total of 58 articles published from 2001 to 2009 in English or French identified through a literature search in seven scientific, bibliographical databases. Searches included terms related to qualitative studies combined with various terms related to HIV/AIDS. The results of this narrative review show that there was a geographical concentration on Nigeria, Ghana, Burkina Faso and Côte d'Ivoire and a strong urban bias, with most studies taking place in the capital cities of these countries. The majority of the studies focused on women or women and men; only four articles dealt exclusively with men, of which only two were on men who have sex with men. The main study groups were people living with HIV, young people or female sex workers. Sexual risk-taking and stigmatization were the themes that were most prominently explored in the articles we reviewed. We conclude that research needs to be strengthened in relation to the analysis of experiences with antiretroviral therapy and the non-optimal access to treatment in West Africa. Also, more research is needed on men and their exposure to HIV/AIDS, as well as on the role of concurrent partnership in the spread of HIV.

  16. The spatial genetic differentiation of the legume pod borer, Maruca vitrata F. (Lepidoptera: Crambidae) populations in West Africa

    KAUST Repository

    Agunbiade, Tolulope A.

    2012-04-17

    The legume pod borer, Maruca vitrata, is an endemic insect pest that causes significant yield loss to the cowpea crop in West Africa. The application of population genetic tools is important in the management of insect pests but such data on M. vitrata is lacking. We applied a set of six microsatellite markers to assess the population structure of M. vitrata collected at five sites from Burkina Faso, Niger and Nigeria. Observed polymorphisms ranged from one (marker 3393) to eight (marker 32008) alleles per locus. Observed and expected heterozygosities ranged from 0.0 to 0.8 and 0.0 to 0.6, respectively. Three of the loci in samples from Nigeria and Burkina Faso deviated significantly from Hardy-Weinberg Equilibrium (HWE), whereas no loci deviated significantly in samples from Niger. Analysis of molecular variance (AMOVA) indicated that 67.3% level of the genetic variation was within individuals compared to 17.3% among populations. A global estimate of F ST=0.1 (ENA corrected F ST=0.1) was significant (Pa=0.05) and corroborated by pairwise F ST values that were significant among all possible comparisons. A significant correlation was predicted between genetic divergence and geographic distance between subpopulations (R2=0.6, P=0.04), and cluster analysis by the program STRUCTURE predicted that co-ancestry of genotypes were indicative of three distinct populations. The spatial genetic variance among M. vitrata in West Africa may be due to limited gene flow, south-north seasonal movement pattern or other reproductive barriers. This information is important for the cultural, chemical and biological control strategies for managing M. vitrata. Copyright © 2012 Cambridge University Press.

  17. Projecting Future Land Use Changes in West Africa Driven by Climate and Socioeconomic Factors: Uncertainties and Implications for Adaptation

    Science.gov (United States)

    Wang, G.; Ahmed, K. F.; You, L.

    2015-12-01

    Land use changes constitute an important regional climate change forcing in West Africa, a region of strong land-atmosphere coupling. At the same time, climate change can be an important driver for land use, although its importance relative to the impact of socio-economic factors may vary significant from region to region. This study compares the contributions of climate change and socioeconomic development to potential future changes of agricultural land use in West Africa and examines various sources of uncertainty using a land use projection model (LandPro) that accounts for the impact of socioeconomic drivers on the demand side and the impact of climate-induced crop yield changes on the supply side. Future crop yield changes were simulated by a process-based crop model driven with future climate projections from a regional climate model, and future changes of food demand is projected using a model for policy analysis of agricultural commodities and trade. The impact of human decision-making on land use was explicitly considered through multiple "what-if" scenarios to examine the range of uncertainties in projecting future land use. Without agricultural intensification, the climate-induced decrease of crop yield together with increase of food demand are found to cause a significant increase in agricultural land use at the expense of forest and grassland by the mid-century, and the resulting land use land cover changes are found to feed back to the regional climate in a way that exacerbates the negative impact of climate on crop yield. Analysis of results from multiple decision-making scenarios suggests that human adaptation characterized by science-informed decision making to minimize land use could be very effective in many parts of the region.

  18. Access to Risk Mitigating Weather Forecasts and Changes in Farming Operations in East and West Africa: Evidence from a Baseline Survey

    Directory of Open Access Journals (Sweden)

    Abayomi Samuel Oyekale

    2015-10-01

    Full Text Available Unfavorable weather currently ranks among the major challenges facing agricultural development in many African countries. Impact mitigation through access to reliable and timely weather forecasts and other adaptive mechanisms are foremost in Africa’s policy dialogues and socio-economic development agendas. This paper analyzed the factors influencing access to forecasts on incidence of pests/diseases (PD and start of rainfall (SR. The data were collected by Climate Change Agriculture and Food Security (CCAFS and analyzed with Probit regression separately for East Africa, West Africa and the combined dataset. The results show that 62.7% and 56.4% of the farmers from East and West Africa had access to forecasts on start of rainfall, respectively. In addition, 39.3% and 49.4% of the farmers from East Africa indicated that forecasts on outbreak of pests/diseases and start of rainfall were respectively accompanied with advice as against 18.2% and 41.9% for West Africa. Having received forecasts on start of rainfall, 24.0% and 17.6% of the farmers from East and West Africa made decisions on timing of farming activities respectively. Probabilities of having access to forecasts on PD significantly increased with access to formal education, farm income and previous exposure to climatic shocks. Furthermore, probabilities of having access to forecasts on SR significantly increased (p < 0.05 with access to business income, radio and perception of more erratic rainfall, among others. It was recommended that promotion of informal education among illiterate farmers would enhance their climatic resilience, among others.

  19. The impact of human conflict on the genetics of Mastomys natalensis and Lassa virus in West Africa.

    Directory of Open Access Journals (Sweden)

    Aude Lalis

    Full Text Available Environmental changes have been shown to play an important role in the emergence of new human diseases of zoonotic origin. The contribution of social factors to their spread, especially conflicts followed by mass movement of populations, has not been extensively investigated. Here we reveal the effects of civil war on the phylogeography of a zoonotic emerging infectious disease by concomitantly studying the population structure, evolution and demography of Lassa virus and its natural reservoir, the rodent Mastomys natalensis, in Guinea, West Africa. Analysis of nucleoprotein gene sequences enabled us to reconstruct the evolutionary history of Lassa virus, which appeared 750 to 900 years ago in Nigeria and only recently spread across western Africa (170 years ago. Bayesian demographic inferences revealed that both the host and the virus populations have gone recently through severe genetic bottlenecks. The timing of these events matches civil war-related mass movements of refugees and accompanying environmental degradation. Forest and habitat destruction and human predation of the natural reservoir are likely explanations for the sharp decline observed in the rodent populations, the consequent virus population decline, and the coincident increased incidence of Lassa fever in these regions. Interestingly, we were also able to detect a similar pattern in Nigeria coinciding with the Biafra war. Our findings show that anthropogenic factors may profoundly impact the population genetics of a virus and its reservoir within the context of an emerging infectious disease.

  20. The impact of human conflict on the genetics of Mastomys natalensis and Lassa virus in West Africa.

    Science.gov (United States)

    Lalis, Aude; Leblois, Raphaël; Lecompte, Emilie; Denys, Christiane; Ter Meulen, Jan; Wirth, Thierry

    2012-01-01

    Environmental changes have been shown to play an important role in the emergence of new human diseases of zoonotic origin. The contribution of social factors to their spread, especially conflicts followed by mass movement of populations, has not been extensively investigated. Here we reveal the effects of civil war on the phylogeography of a zoonotic emerging infectious disease by concomitantly studying the population structure, evolution and demography of Lassa virus and its natural reservoir, the rodent Mastomys natalensis, in Guinea, West Africa. Analysis of nucleoprotein gene sequences enabled us to reconstruct the evolutionary history of Lassa virus, which appeared 750 to 900 years ago in Nigeria and only recently spread across western Africa (170 years ago). Bayesian demographic inferences revealed that both the host and the virus populations have gone recently through severe genetic bottlenecks. The timing of these events matches civil war-related mass movements of refugees and accompanying environmental degradation. Forest and habitat destruction and human predation of the natural reservoir are likely explanations for the sharp decline observed in the rodent populations, the consequent virus population decline, and the coincident increased incidence of Lassa fever in these regions. Interestingly, we were also able to detect a similar pattern in Nigeria coinciding with the Biafra war. Our findings show that anthropogenic factors may profoundly impact the population genetics of a virus and its reservoir within the context of an emerging infectious disease.

  1. Population genomics reveals that an anthropophilic population of Aedes aegypti mosquitoes in West Africa recently gave rise to American and Asian populations of this major disease vector

    KAUST Repository

    Crawford, Jacob E.

    2017-02-20

    BackgroundThe mosquito Aedes aegypti is the main vector of dengue, Zika, chikungunya and yellow fever viruses. This major disease vector is thought to have arisen when the African subspecies Ae. aegypti formosus evolved from being zoophilic and living in forest habitats into a form that specialises on humans and resides near human population centres. The resulting domestic subspecies, Ae. aegypti aegypti, is found throughout the tropics and largely blood-feeds on humans.ResultsTo understand this transition, we have sequenced the exomes of mosquitoes collected from five populations from around the world. We found that Ae. aegypti specimens from an urban population in Senegal in West Africa were more closely related to populations in Mexico and Sri Lanka than they were to a nearby forest population. We estimate that the populations in Senegal and Mexico split just a few hundred years ago, and we found no evidence of Ae. aegypti aegypti mosquitoes migrating back to Africa from elsewhere in the tropics. The out-of-Africa migration was accompanied by a dramatic reduction in effective population size, resulting in a loss of genetic diversity and rare genetic variants.ConclusionsWe conclude that a domestic population of Ae. aegypti in Senegal and domestic populations on other continents are more closely related to each other than to other African populations. This suggests that an ancestral population of Ae. aegypti evolved to become a human specialist in Africa, giving rise to the subspecies Ae. aegypti aegypti. The descendants of this population are still found in West Africa today, and the rest of the world was colonised when mosquitoes from this population migrated out of Africa. This is the first report of an African population of Ae. aegypti aegypti mosquitoes that is closely related to Asian and American populations. As the two subspecies differ in their ability to vector disease, their existence side by side in West Africa may have important implications for

  2. Relative severity of aflatoxin contamination of cereal crops in West Africa.

    Science.gov (United States)

    Bandyopadhyay, Ranajit; Kumar, Manjula; Leslie, John F

    2007-10-01

    Aflatoxins are a common contaminant of cereals that can cause cancer, liver disease, immune suppression, retarded growth and development, and death, depending on the level and duration of exposure. Maize is an introduced crop to Africa and there have been efforts over the last 20 years or so to replace traditional cereal crops, such as sorghum (Sorghum bicolor) and pearl millet (Pennisetum glaucum), with maize. We found that maize was significantly more heavily colonized by aflatoxin-producing Aspergillus spp. than either sorghum or millet, with overall aflatoxin levels being correspondingly higher. On average, Nigerians consume 138 kg cereals annually. If the primary cereal is sorghum instead of maize, then the risk of aflatoxin-related problems is reduced 4-fold; if it is pearl millet, then the risks are reduced 8-fold. Development programs and other ventures to increase maize production in marginal cropping areas of Africa should be reconsidered and, instead, efforts to improve/maintain traditional crops encouraged.

  3. French for West Africa. A Basic Course for Vocational Educational Training.

    Science.gov (United States)

    Wilkins, Joseph P.; And Others

    This textbook is designed to teach the French used in West African nations. Thus, pronunciation and topics reflect standard usage in those countries. Chapters generally consist of several dialogues, grammar and cultural notes, and numerous pattern drills and other exercises. English translations for the dialogues are provided in the back of the…

  4. Variation in soil carbon stocks and their determinants across a precipitation gradient in West Africa

    NARCIS (Netherlands)

    Saiz, G.; Bird, M.I.; Domingues, T.F.; Schrodt, F.; Schwartz, M.; Veenendaal, E.M.

    2012-01-01

    We examine the influence of climate, soil properties and vegetation characteristics on soil organic carbon (SOC) along a transect of West African ecosystems sampled across a precipitation gradient on contrasting soil types stretching from Ghana (15°N) to Mali (7°N). Our findings derive from a total

  5. Morphological Characterization of African Bush Mango trees (Irvingia species) in the Dahomey Gap (West Africa)

    NARCIS (Netherlands)

    Vihotogbe, R.; Berg, van den R.G.; Sosef, M.S.M.

    2013-01-01

    The variation of the morphological characters of bitter and sweet African bush mango trees (Irvingia species) was investigated in the Dahomey Gap which is the West African savannah woodland area separating the Upper and the Lower Guinean rain forest blocks. African bush mangoes have been rated as th

  6. An overview of the socio-cultural and psychiatric aspects of women's reproductive health in West Africa.

    Science.gov (United States)

    Aina, O F

    2007-09-01

    The challenges associated with women reproductive health in West African sub region have over the years become a source of concern to relevant world bodies such as WHO, UNFPA, World Bank etc. Some of these challenges include Infertility, Family Planning and Female Genital Mutilation (FGM). However, of greater concern is the scourge of Sexually Transmitted Diseases (STDs) most especially HIV/ AIDS and the unacceptably high maternal mortality in the sub region where Nigeria alone accounts for the highest percentage (10%) of the global 60,000 maternal deaths annually. Significant psychiatric complications such as anxiety and depression are associated with menstruation and menopause. However, the postpartum period is the most vulnerable with significant proportion of women developing such psychopathologies as Puerperal (maternity) blues, Postpartum Depression (PPD) and Acute Organic Brain Syndrome. Sociocultural factors, the dearth of psychiatrists in West Africa coupled with the poor or non-recognition of the psychiatric complications by the obstetric staff have not allowed enough clinical attention to be paid to these problems. It is thus advocated that improvement in the maternal and child health care component of the primary health care (PHC) services will go a long way to attenuate the psychiatric complications associated with childbirth.

  7. Climatic instability in west equatorial Africa during the Mid- and Late Holocene

    OpenAIRE

    Marret, F.; Maley, Jean; Scourse, J.

    2006-01-01

    Millennial-scale climatic variations have punctuated the Holocene characterised by abrupt changes from warm to cool or wetter to drier conditions. Amongst these climatic events, there is increased evidence for an abrupt multicentennial shift of climatic conditions around 3.8/3.7 kyr BP (4.1 cal. kyr BP) in mid- to low-latitude regions which had a profound impact on landscape and population migration. In the Mediterranean region, subtropical, tropical and equatorial Africa, a number of contine...

  8. Genome-wide and fine-resolution association analysis of malaria in West Africa

    OpenAIRE

    Jallow, Muminatou; Teo, Yik Ying; Kerrin S Small; Kirk A Rockett; Deloukas, Panos; Taane G Clark; Kivinen, Katja; Kalifa A Bojang; Conway, David J.; Pinder, Margaret; Sirugo, Giorgio; Sisay-Joof, Fatou; Usen, Stanley; Auburn, Sarah; Suzannah J Bumpstead

    2009-01-01

    We report a genome-wide association (GWA) study of severe malaria in The Gambia. The initial GWA scan included 2,500 children genotyped on the Affymetrix 500K GeneChip, and a replication study included 3,400 children. We used this to examine the performance of GWA methods in Africa. We found considerable population stratification, and also that signals of association at known malaria resistance loci were greatly attenuated owing to weak linkage disequilibrium (LD). To investigate possible sol...

  9. Decreasing incidence of cryptococcal meningitis in West Africa in the era of highly active antiretroviral therapy.

    Science.gov (United States)

    Bamba, Sanata; Lortholary, Olivier; Sawadogo, Adrien; Millogo, Athanase; Guiguemdé, Robert T; Bretagne, Stéphane

    2012-05-15

    Cryptococcosis remains a major opportunistic infection in AIDS in sub-Saharan Africa, but few data exist from its western part. We report data from Bobo Dioulasso University Hospital, Bobo-Dioulasso, Burkina Faso, with a steady decline from 14 to two cases per year from 2002 to 2010 which contrasts with the increase (from 147 to 3940) of patients on antiretroviral therapy (ART). Better ART availability decreases the incidence of cryptococcosis in Burkina Faso.

  10. Processes Underpinning Development and Maintenance of Diversity in Rice in West Africa: Evidence from Combining Morphological and Molecular Markers

    Science.gov (United States)

    Maat, Harro; Richards, Paul; Struik, Paul C.

    2014-01-01

    We assessed the interplay of artificial and natural selection in rice adaptation in low-input farming systems in West Africa. Using 20 morphological traits and 176 molecular markers, 182 farmer varieties of rice (Oryza spp.) from 6 West African countries were characterized. Principal component analysis showed that the four botanical groups (Oryza sativa ssp. indica, O. sativa ssp. japonica, O. glaberrima, and interspecific farmer hybrids) exhibited different patterns of morphological diversity. Regarding O. glaberrima, morphological and molecular data were in greater conformity than for the other botanical groups. A clear difference in morphological features was observed between O. glaberrima rices from the Togo hills and those from the Upper Guinea Coast, and among O. glaberrima rices from the Upper Guinea Coast. For the other three groups such clear patterns were not observed. We argue that this is because genetic diversity is shaped by different environmental and socio-cultural selection pressures. For O. glaberrima, recent socio-cultural selection pressures seemed to restrict genetic diversity while this was not observed for the other botanical groups. We also show that O. glaberrima still plays an important role in the selection practices of farmers and resulting variety development pathways. This is particularly apparent in the case of interspecific farmer hybrids where a relationship was found between pericarp colour, panicle attitude and genetic diversity. Farmer varieties are the product of long and complex trajectories of selection governed by local human agency. In effect, rice varieties have emerged that are adapted to West African farming conditions through genotype × environment × society interactions. The diversity farmers maintain in their rice varieties is understood to be part of a risk-spreading strategy that also facilitates successful and often serendipitous variety innovations. We advocate, therefore, that farmers and farmer varieties should

  11. Processes underpinning development and maintenance of diversity in rice in West Africa: evidence from combining morphological and molecular markers.

    Directory of Open Access Journals (Sweden)

    Alfred Mokuwa

    Full Text Available We assessed the interplay of artificial and natural selection in rice adaptation in low-input farming systems in West Africa. Using 20 morphological traits and 176 molecular markers, 182 farmer varieties of rice (Oryza spp. from 6 West African countries were characterized. Principal component analysis showed that the four botanical groups (Oryza sativa ssp. indica, O. sativa ssp. japonica, O. glaberrima, and interspecific farmer hybrids exhibited different patterns of morphological diversity. Regarding O. glaberrima, morphological and molecular data were in greater conformity than for the other botanical groups. A clear difference in morphological features was observed between O. glaberrima rices from the Togo hills and those from the Upper Guinea Coast, and among O. glaberrima rices from the Upper Guinea Coast. For the other three groups such clear patterns were not observed. We argue that this is because genetic diversity is shaped by different environmental and socio-cultural selection pressures. For O. glaberrima, recent socio-cultural selection pressures seemed to restrict genetic diversity while this was not observed for the other botanical groups. We also show that O. glaberrima still plays an important role in the selection practices of farmers and resulting variety development pathways. This is particularly apparent in the case of interspecific farmer hybrids where a relationship was found between pericarp colour, panicle attitude and genetic diversity. Farmer varieties are the product of long and complex trajectories of selection governed by local human agency. In effect, rice varieties have emerged that are adapted to West African farming conditions through genotype × environment × society interactions. The diversity farmers maintain in their rice varieties is understood to be part of a risk-spreading strategy that also facilitates successful and often serendipitous variety innovations. We advocate, therefore, that farmers and

  12. Pan-African Paleostresses and Reactivation of the Eburnean Basement Complex in Southeast Ghana (West Africa

    Directory of Open Access Journals (Sweden)

    Mahaman Sani Tairou

    2012-01-01

    Full Text Available This faulting tectonics analysis concerns the southernmost segment of the Dahomeyide Orogen and the West-African craton eastern margin in southeast Ghana. The analysis of strike-slip faults in the frontal units of the Dahomeyide Belt indicates that four distinct compressive events (NE-SW, ENE-WSW to E-W, ESE-WNW to SE-NW and SE-NW to SSE-NNW originated the juxtaposition of the Pan-African Mobile Zone and the West-African craton. These paleostress systems define a clockwise rotation of the compressional axis during the structuring of the Dahomeyide Orogen (650–550 Ma. The SE-NW and SSE-NNW to N-S compressional axes in the cratonic domain and its cover (Volta Basin suggest that the reactivation of the eastern edge of the West African craton is coeval with the last stages of the Pan-African tectogenesis in southeast Ghana. An extensional episode expressed as late normal faulting is also recorded in this study. This E-W to SE-NW extension, which is particular to the southernmost part of the Dahomeyide Belt, appears to be post-Pan-African. This extension probably contributed to the formation of a major Jurassic rifting zone that originated the Central Atlantic and the Benue Trough.

  13. Bryophytes from the Republic of Equatorial Guinea (West-Central Africa) : 1., introduction and preliminary checklist

    OpenAIRE

    1996-01-01

    A preliminary list consisting of 159 bryophyte taxa (82 liverworts and 77 mosses) has been compiled from the bryological literature on the Republic of Equatorial Guinea (Central-Western Africa) until 1995. A general overview of the physical features and vegetation of the country, and an account of the history of its bryological exploration are also included. Se han reunido en un catálogo preliminar los 159 táxones de briófitos (82 hepáticas y 77 musgos) de la República de Guinea Ecuatorial...

  14. First Report of Outbreaks of the Fall Armyworm Spodoptera frugiperda (J E Smith) (Lepidoptera, Noctuidae), a New Alien Invasive Pest in West and Central Africa

    Science.gov (United States)

    Sankung, Sagnia B.; Togola, Abou; Tamò, Manuele

    2016-01-01

    The fall armyworm Spodoptera frugiperda is a prime noctuid pest of maize on the American continents where it has remained confined despite occasional interceptions by European quarantine services in recent years. The pest has currently become a new invasive species in West and Central Africa where outbreaks were recorded for the first time in early 2016. The presence of at least two distinct haplotypes within samples collected on maize in Nigeria and São Tomé suggests multiple introductions into the African continent. Implications of this new threat to the maize crop in tropical Africa are briefly discussed. PMID:27788251

  15. A new Xylaria (Xylariaceae, Ascomycota) from Cameroon

    DEFF Research Database (Denmark)

    Læssøe, Thomas; Cheek, M.

    2002-01-01

    A new species of Xylaria (Xylariaceae, Ascomycota) from western Cameroon is described on teleomorphic and cultural characters.......A new species of Xylaria (Xylariaceae, Ascomycota) from western Cameroon is described on teleomorphic and cultural characters....

  16. Chemical and aerosol characterisation of the troposphere over West Africa during the monsoon period as part of AMMA

    Directory of Open Access Journals (Sweden)

    C. E. Reeves

    2010-08-01

    Full Text Available During June, July and August 2006 five aircraft took part in a campaign over West Africa to observe the aerosol content and chemical composition of the troposphere and lower stratosphere as part of the African Monsoon Multidisciplinary Analysis (AMMA project. These are the first such measurements in this region during the monsoon period. In addition to providing an overview of the tropospheric composition, this paper provides a description of the measurement strategy (flights performed, instrumental payloads, wing-tip to wing-tip comparisons and points to some of the important findings discussed in more detail in other papers in this special issue.

    The ozone data exhibits an "S" shaped vertical profile which appears to result from significant losses in the lower troposphere due to rapid deposition to forested areas and photochemical destruction in the moist monsoon air, and convective uplift of ozone-poor air to the upper troposphere. This profile is disturbed, particularly in the south of the region, by the intrusions in the lower and middle troposphere of air from the southern hemisphere impacted by biomass burning. Comparisons with longer term data sets suggest the impact of these intrusions on West Africa in 2006 was greater than in other recent wet seasons. There is evidence for net photochemical production of ozone in these biomass burning plumes as well as in urban plumes, in particular that from Lagos, convective outflow in the upper troposphere and in boundary layer air affected by nitrogen oxide emissions from recently wetted soils. This latter effect, along with enhanced deposition to the forested areas, contributes to a latitudinal gradient of ozone in the lower troposphere. Biogenic volatile organic compounds are also important in defining the composition both for the boundary layer and upper tropospheric convective outflow.

    Mineral dust was found to be the most abundant and ubiquitous aerosol type in the

  17. Chemical and aerosol characterisation of the troposphere over West Africa during the monsoon period as part of AMMA

    Directory of Open Access Journals (Sweden)

    C. E. Reeves

    2010-03-01

    Full Text Available During June, July and August 2006 five aircraft took part in a campaign over West Africa to observe the aerosol content and chemical composition of the troposphere and lower stratosphere as part of the African Monsoon Multidisciplinary Analysis (AMMA project. These are the first such measurements in this region during the monsoon period. In addition to providing an overview of the tropospheric composition, this paper provides a description of the measurement strategy (flights performed, instrumental payloads, wing-tip to wing-tip comparisons and points to some of the important findings discussed in more detailed in other papers in this special issue.

    The ozone data exhibits an "S" shaped vertical profile which appears to result from significant losses in the lower troposphere due to rapid deposition to forested areas and photochemical destruction in the moist monsoon air, and convective uplift of O3-poor air to the upper troposphere. This profile is disturbed, particularly in the south of the region, by the intrusions in the lower and middle troposphere of air from the Southern Hemisphere impacted by biomass burning. Comparisons with longer term data sets suggest the impact of these intrusions on West Africa in 2006 was greater than in other recent wet seasons. There is evidence for net photochemical production of ozone in these biomass burning plumes as well as in urban plumes, in particular that from Lagos, convective outflow in the upper troposphere and in boundary layer air affected by nitrogen oxide emissions from recently wetted soils. This latter effect, along with enhanced deposition to the forested areas, contributes to a latitudinal gradient of ozone in the lower troposphere. Biogenic volatile organic compounds are also important in defining the composition both for the boundary layer and upper tropospheric convective outflow.

    Mineral dust was found to be the most abundant and ubiquitous aerosol type in the

  18. Euros vs. yuan: comparing European and Chinese fishing access in West Africa.

    Science.gov (United States)

    Belhabib, Dyhia; Sumaila, U Rashid; Lam, Vicky W Y; Zeller, Dirk; Le Billon, Philippe; Abou Kane, Elimane; Pauly, Daniel

    2015-01-01

    We compare the performance of European Union (EU) and Chinese fisheries access agreements with West African countries in terms of illegal and unreported fishing, economic equity, and patterns of exploitation. Bottom-up re-estimations of catch reveal that the EU (1.6 million t•year(-1)) and China (2.3 million t•year(-1)) report only 29% and 8%, respectively, of their estimated total catches (including estimated discards whenever possible) from West African countries between 2000 and 2010. EU catches are declining, while Chinese catches are increasing and are yet to reach the historic maximum level of EU catches (3 million t•year(-1) on average in the 1970s-1980s). The monetary value of EU fishing agreements, correlated in theory with reported catches, is straightforward to access, in contrast to Chinese agreements. However, once quantified, the value of Chinese agreements is readily traceable within the African economy through the different projects they directly cover, in contrast to the funds disbursed [to host governments] by the EU. Overall, China provides resources equivalent to about 4% of the ex-vessel value [value at landing] of the catch taken by Chinese distant-water fleets from West African waters, while the EU pays 8%. We address the difficulties of separating fees directly related to fishing from other economic or political motivations for Chinese fees, which could introduce a bias to the present findings as this operation is not performed for EU access fees officially related to fishing. Our study reveals that the EU and China perform similarly in terms of illegal fishing, patterns of exploitation and sustainability of resource use, while under-reporting by the EU increases and that by China decreases. The EU agreements provide, in theory, room for improving scientific research, monitoring and surveillance, suggesting a better performance than for Chinese agreements, but the end-use of the EU funds are more difficult, and sometime impossible to

  19. Euros vs. yuan: comparing European and Chinese fishing access in West Africa.

    Directory of Open Access Journals (Sweden)

    Dyhia Belhabib

    Full Text Available We compare the performance of European Union (EU and Chinese fisheries access agreements with West African countries in terms of illegal and unreported fishing, economic equity, and patterns of exploitation. Bottom-up re-estimations of catch reveal that the EU (1.6 million t•year(-1 and China (2.3 million t•year(-1 report only 29% and 8%, respectively, of their estimated total catches (including estimated discards whenever possible from West African countries between 2000 and 2010. EU catches are declining, while Chinese catches are increasing and are yet to reach the historic maximum level of EU catches (3 million t•year(-1 on average in the 1970s-1980s. The monetary value of EU fishing agreements, correlated in theory with reported catches, is straightforward to access, in contrast to Chinese agreements. However, once quantified, the value of Chinese agreements is readily traceable within the African economy through the different projects they directly cover, in contrast to the funds disbursed [to host governments] by the EU. Overall, China provides resources equivalent to about 4% of the ex-vessel value [value at landing] of the catch taken by Chinese distant-water fleets from West African waters, while the EU pays 8%. We address the difficulties of separating fees directly related to fishing from other economic or political motivations for Chinese fees, which could introduce a bias to the present findings as this operation is not performed for EU access fees officially related to fishing. Our study reveals that the EU and China perform similarly in terms of illegal fishing, patterns of exploitation and sustainability of resource use, while under-reporting by the EU increases and that by China decreases. The EU agreements provide, in theory, room for improving scientific research, monitoring and surveillance, suggesting a better performance than for Chinese agreements, but the end-use of the EU funds are more difficult, and sometime

  20. Catalyzing Gender Equality-Focused Clean Energy Development in West Africa

    Energy Technology Data Exchange (ETDEWEB)

    2016-06-01

    The Economic Community of West African States (ECOWAS) Regional Center for Renewable Energy and Energy Efficiency (ECREEE) partnered with the Clean Energy Solutions Center (Solutions Center), the African Development Bank and other institutions to develop a Situation Analysis of Energy and Gender Issues in ECOWAS Member States. Through a systematic approach to assess interlinked gender and energy issues in the region, the report puts forth a number of key findings. This brochure highlights ECREEE's partnership with the Solutions Center and key findings from the report.

  1. Changes in lion (Panthera leo) home range size in Waza National Park, Cameroon

    NARCIS (Netherlands)

    Tumenta, P.N.; Van't Zelfde, M.; Croes, B.M.; Buij, R.; Funston, P.J.; Haes, de H.A.U.; longh, De H.H.

    2013-01-01

    The spatial ecology of Africa lions (Panthera leo) was studied from 2007 to 2009 in Waza National Park, Cameroon, by equipping individual lions with GPS/VHF radio-collars. Mean home range estimates using 100% minimum convex polygons (MCP) and 95% kernel-density estimation (KDE) were respectively 101

  2. Soil carbon and plant diversity distribution at the farm level in the savannah region of Northern Togo (West Africa

    Directory of Open Access Journals (Sweden)

    M.-T. Sebastià

    2008-10-01

    Full Text Available In western Africa, soil organic matter is a source of fertility for food provision and a tool for climate mitigation. In the Savannah region, strong soil degradation linked to an increase in population threatens organic matter conservation and agricultural yield. Soil degradation is also expected to impact biodiversity and, with it, increase the vulnerability of ecosystem goods and services, including the storage of soil organic carbon. Studies of land use, plant species composition and soil fertility were conducted for a conservation project at a demonstration farm in Northern Togo (West Africa, host to various management regimes. Results showed a low organic matter content of the surface soil horizons, often around 0.5%. The highest values were found in a sacred forest within the farm (2.2%. Among crops, rice had the highest soil organic matter, around 1%. In a survey of grasslands, pastures showed the highest organic matter content, with vegetation composition differing from grazed fallows and abandoned grasslands. Plant species richness showed a positive relationship with soil organic matter (R2adj=41.2%, but only by the end of the wet season, when species richness was also highest. Sampling date had a strong effect on vegetation composition. Results showed a strong influence of human activity on soil formation and distribution, and also on plant diversity. The soil characteristics found under the permanent forest suggest a high potential of the soils of the region for improvement of both agricultural yields and as a potential carbon sink relevant to global change policies.

  3. HIV status disclosure and retention in care in HIV-infected adolescents on antiretroviral therapy (ART in West Africa.

    Directory of Open Access Journals (Sweden)

    Elise Arrivé

    Full Text Available OBJECTIVE: We assessed the effect of HIV status disclosure on retention in care from initiation of antiretroviral therapy (ART among HIV-infected children aged 10 years or more in Cote d'Ivoire, Mali and Sénégal. METHODS: Multi-centre cohort study within five paediatric clinics participating in the IeDEA West Africa collaboration. HIV-infected patients were included in this study if they met the following inclusion criteria: aged 10-21 years while on ART; having initiated ART ≥ 200 days before the closure date of the clinic database; followed ≥ 15 days from ART initiation in clinics with ≥ 10 adolescents enrolled. Routine follow-up data were merged with those collected through a standardized ad hoc questionnaire on awareness of HIV status. Probability of retention (no death or loss-to-follow-up was estimated with Kaplan-Meier method. Cox proportional hazard model with date of ART initiation as origin and a delayed entry at date of 10th birthday was used to identify factors associated with death or loss-to-follow-up. RESULTS: 650 adolescents were available for this analysis. Characteristics at ART initiation were: median age of 10.4 years; median CD4 count of 224 cells/mm³ (47% with severe immunosuppression, 48% CDC stage C/WHO stage 3/4. The median follow-up on ART after the age of 10 was 23.3 months; 187 adolescents (28.8% knew their HIV status. The overall probability of retention at 36 months after ART initiation was 74.6% (95% confidence interval [CI]: 70.5-79.0 and was higher for those disclosed compared to those not: adjusted hazard ratio for the risk of being death or loss-to-follow-up = 0.23 (95% CI: 0.13-0.39. CONCLUSION: About 2/3 of HIV-infected adolescents on ART were not aware of their HIV status in these ART clinics in West Africa but disclosed HIV status improved retention in care. The disclosure process should be thus systematically encouraged and organized in adolescent populations.

  4. Chinese Public Attention to the Outbreak of Ebola in West Africa: Evidence from the Online Big Data Platform

    Science.gov (United States)

    Liu, Kui; Li, Li; Jiang, Tao; Chen, Bin; Jiang, Zhenggang; Wang, Zhengting; Chen, Yongdi; Jiang, Jianmin; Gu, Hua

    2016-01-01

    Objective: The outbreak of the Ebola epidemic in West Africa in 2014 exerted enormous global public reaction via the Internet and social media. This study aimed to investigate and evaluate the public reaction to Ebola in China and identify the primitive correlation between possible influence factors caused by the outbreak of Ebola in West Africa and Chinese public attention via Internet surveillance. Methods: Baidu Index (BDI) and Sina Micro Index (SMI) were collected from their official websites, and the disease-related data were recorded from the websites of the World Health Organization (WHO), U.S. Centers for Disease Control and Prevention (CDC), and U.S. National Ministries of Health. The average BDI of Internet users in different regions were calculated to identify the public reaction to the Ebola outbreak. Spearman’s rank correlation was used to check the relationship of epidemic trends with BDI and SMI. Additionally, spatio-temporal analysis and autocorrelation analysis were performed to detect the clustered areas with the high attention to the topic of “Ebola”. The related news reports were collected from authoritative websites to identify potential patterns. Results: The BDI and the SMI for “Ebola” showed a similar fluctuating trend with a correlation coefficient = 0.9 (p < 0.05). The average BDI in Beijing, Tibet, and Shanghai was higher than other cities. However, the disease-related indicators did not identify potential correlation with both indices above. A hotspot area was detected in Tibet by local autocorrelation analysis. The most likely cluster identified by spatiotemporal cluster analysis was in the northeast regions of China with the relative risk (RR) of 2.26 (p ≤ 0.01) from 30 July to 14 August in 2014. Qualitative analysis indicated that negative news could lead to a continuous increase of the public’s attention until the appearance of a positive news report. Conclusions: Confronted with the risk of cross-border transmission of

  5. Assessing climate change impacts on sorghum and millet yields in the Sudanian and Sahelian savannas of West Africa

    Science.gov (United States)

    Sultan, B.; Roudier, P.; Quirion, P.; Alhassane, A.; Muller, B.; Dingkuhn, M.; Ciais, P.; Guimberteau, M.; Traore, S.; Baron, C.

    2013-03-01

    Sub-Saharan West Africa is a vulnerable region where a better quantification and understanding of the impact of climate change on crop yields is urgently needed. Here, we have applied the process-based crop model SARRA-H calibrated and validated over multi-year field trials and surveys at eight contrasting sites in terms of climate and agricultural practices in Senegal, Mali, Burkina Faso and Niger. The model gives a reasonable correlation with observed yields of sorghum and millet under a range of cultivars and traditional crop management practices. We applied the model to more than 7000 simulations of yields of sorghum and millet for 35 stations across West Africa and under very different future climate conditions. We took into account 35 possible climate scenarios by combining precipitation anomalies from -20% to 20% and temperature anomalies from +0 to +6 °C. We found that most of the 35 scenarios (31/35) showed a negative impact on yields, up to -41% for +6 °C/ - 20% rainfall. Moreover, the potential future climate impacts on yields are very different from those recorded in the recent past. This is because of the increasingly adverse role of higher temperatures in reducing crop yields, irrespective of rainfall changes. When warming exceeds +2 °C, negative impacts caused by temperature rise cannot be counteracted by any rainfall change. The probability of a yield reduction appears to be greater in the Sudanian region (southern Senegal, Mali, Burkina Faso, northern Togo and Benin), because of an exacerbated sensitivity to temperature changes compared to the Sahelian region (Niger, Mali, northern parts of Senegal and Burkina Faso), where crop yields are more sensitive to rainfall change. Finally, our simulations show that the photoperiod-sensitive traditional cultivars of millet and sorghum used by local farmers for centuries seem more resilient to future climate conditions than modern cultivars bred for their high yield potential (-28% versus -40% for

  6. Non-falciparum malaria infections in pregnant women in West Africa

    DEFF Research Database (Denmark)

    Williams, John; Njie, Fanta; Cairns, Matthew

    2016-01-01

    BACKGROUND: Non-Plasmodium falciparum malaria infections are found in many parts of sub-Saharan Africa but little is known about their importance in pregnancy. METHODS: Blood samples were collected at first antenatal clinic attendance from 2526 women enrolled in a trial of intermittent screening...... and treatment of malaria in pregnancy (ISTp) versus intermittent preventive treatment (IPTp) conducted in Burkina Faso, The Gambia, Ghana and Mali. DNA was extracted from blood spots and tested for P. falciparum, Plasmodium vivax, Plasmodium malariae and Plasmodium ovale using a nested PCR test. Risk factors...... for a non-falciparum malaria infection were investigated and the influence of these infections on the outcome of pregnancy was determined. RESULTS: P. falciparum infection was detected frequently (overall prevalence by PCR: 38.8 %, [95 % CI 37.0, 40.8]), with a prevalence ranging from 10.8 % in The Gambia...

  7. Solid waste characterization in Kétao, a rural town in Togo, West Africa

    DEFF Research Database (Denmark)

    Edjabou, Vincent Maklawe Essonanawe; Møller, Jacob; Christensen, Thomas Højlund

    2012-01-01

    In Africa the majority of solid waste data is for big cities. Small and rural towns are generally neglected and waste data from these areas are often unavailable, which makes planning a proper solid waste management difficult. This paper presents the results from two waste characterization projects...... locally and do not enter the waste stream. The study suggests that additional recycling is not feasible, but further examination of the degradability of the organic fraction is needed in order to assess whether the residual waste should be composed or landfilled....... conducted in Kétao, a rural town in Togo during the rainy season and the dry season in 2010. The seasonal variation has a significant impact on the waste stream. The household waste generation rate was estimated at 0.22 kg person−1 day−1 in the dry season and 0.42 in the rainy season. Likewise, the waste...

  8. Ebola Virus Disease Epidemic: What Can the World Learn and Not Learn from West Africa?

    Directory of Open Access Journals (Sweden)

    Romuladus E. Azuine, DrPH, RN

    2015-03-01

    Full Text Available WITH over 4,500 deaths and counting, and new cases identified in two developed countries that are struggling and faltering in their handling of the epidemic, the 2014 Ebola Virus Disease (EVD epidemic is unlike any of its kind ever encountered. The ability of some poor, resource-limited, developing countries in sub-Saharan Africa to efficiently handle the epidemic within their shores provides some lessons learned for the global health community. Among others, the 2014 EVD epidemic teaches us that it is time to put the “P” back in public and population health around the world. The global health community must support a sustainable strategy to mitigate Ebola virus and other epidemics both within and outside their shores, even after the cameras are gone. Ebola virus must not be called the disease of the poor and developing world.

  9. Wetland plant communities in the Potchefstroom Municipal Area, North-West, South Africa

    Directory of Open Access Journals (Sweden)

    S. S. Cilliers

    1998-12-01

    Full Text Available Wetlands in natural areas in South Africa have been described before, but no literature exists concerning the phyto­sociology of urban wetlands. The objective of this study was to conduct a complete vegetation analysis of the wetlands in the Potchefstroom Municipal Area. Using a numerical classification technique (TWINSPAN as a first approximation, the classification was refined by using Braun-Blanquet procedures. The result is a phytosociological table from which a number of unique plant communities are recognised. These urban wetlands are characterised by a high species diversity, which is unusual for wetlands. Reasons for the high species diversity could be the different types of disturbances occurring in this area. Results of this study can be used to construact more sensible management practises for these wetlands.  

  10. PIXE analysis and provenance study of archaeological potsherds from West Africa

    Science.gov (United States)

    Fontes, P.; Brissaud, I.; Lagarde, G.; Leblanc, J.; Person, A.; Saliege, J.-F.; Heitz, Ch.

    1984-04-01

    The present work is part of an archaeometrical programme dealing with prospection and analytical studies of sites contemporaneous with the West-African Empires during the Middle Ages. The measurement of the chemical composition of archaeological potsherds has been undertaken using PIXE analysis in order to characterize the production areas and to investigate commercial and cultural exchanges in the Inland Niger Delta (Mali). Samples consist of thick clay pellets pressed without binding material. Irradiations were performed in the proton beam of a 4 MV Van de Graaff accelerator. Experimental conditions were the same as those suggested in a previous work. The analysis of a standard pottery has shown that the concentration of more than twenty elements, heavier than aluminium, can be measured with good reproducibility and sufficient accuracy. Experiments were carried out in two steps, a 1 MeV irradiation for detection of elements ranging from aluminium to iron, and then irradition by 3 MeV protons for elements heavier than iron. Five archaeological sites have been considered and especially the megalithic sites of Tondidarou and Dabi, both on the shores of the Tagadji lake, in the South-West of Tombouctou. The results are discussed using statistical treatment and cluster analysis. The typical composition of the clay from this region is then presented.

  11. Spatial genetic structuring of baobab (Adansonia digitata, Malvaceae) in the traditional agroforestry systems of West Africa.

    Science.gov (United States)

    Kyndt, Tina; Assogbadjo, Achille E; Hardy, Olivier J; Glele Kakaï, Romain; Sinsin, Brice; Van Damme, Patrick; Gheysen, Godelieve

    2009-05-01

    This study evaluates the spatial genetic structure of baobab (Adansonia digitata) populations from West African agroforestry systems at different geographical scales using AFLP fingerprints. Eleven populations from four countries (Benin, Ghana, Burkina Faso, and Senegal) had comparable levels of genetic diversity, although the two populations in the extreme west (Senegal) had less diversity. Pairwise F(ST) ranged from 0.02 to 0.28 and increased with geographic distance, even at a regional scale. Gene pools detected by Bayesian clustering seem to be a byproduct of the isolation-by-distance pattern rather than representing actual discrete entities. The organization of genetic diversity appears to result essentially from spatially restricted gene flow, with some influences of human seed exchange. Despite the potential for relatively long-distance pollen and seed dispersal by bats within populations, statistically significant spatial genetic structuring within populations (SGS) was detected and gave a mean indirect estimate of neighborhood size of ca. 45. This study demonstrated that relatively high levels of genetic structuring are present in baobab at both large and within-population level, which was unexpected in regard to its dispersal by bats and the influence of human exchange of seeds. Implications of these results for the conservation of baobab populations are discussed.

  12. High Resolution Simulations of Future Climate in West Africa Using a Variable-Resolution Atmospheric Model

    Science.gov (United States)

    Adegoke, J. O.; Engelbrecht, F.; Vezhapparambu, S.

    2013-12-01

    In previous work demonstrated the application of a var¬iable-resolution global atmospheric model, the conformal-cubic atmospheric model (CCAM), across a wide range of spatial and time scales to investigate the ability of the model to provide realistic simulations of present-day climate and plausible projections of future climate change over sub-Saharan Africa. By applying the model in stretched-grid mode the versatility of the model dynamics, numerical formulation and physical parameterizations to function across a range of length scales over the region of interest, was also explored. We primarily used CCAM to illustrate the capability of the model to function as a flexible downscaling tool at the climate-change time scale. Here we report on additional long term climate projection studies performed by downscaling at much higher resolutions (8 Km) over an area that stretches from just south of Sahara desert to the southern coast of the Niger Delta and into the Gulf of Guinea. To perform these simulations, CCAM was provided with synoptic-scale forcing of atmospheric circulation from 2.5 deg resolution NCEP reanalysis at 6-hourly interval and SSTs from NCEP reanalysis data uses as lower boundary forcing. CCAM 60 Km resolution downscaled to 8 Km (Schmidt factor 24.75) then 8 Km resolution simulation downscaled to 1 Km (Schmidt factor 200) over an area approximately 50 Km x 50 Km in the southern Lake Chad Basin (LCB). Our intent in conducting these high resolution model runs was to obtain a deeper understanding of linkages between the projected future climate and the hydrological processes that control the surface water regime in this part of sub-Saharan Africa.

  13. Determination of the water quality index ratings of water in the Mpumalanga and North West provinces, South Africa

    Science.gov (United States)

    Wanda, Elijah M. M.; Mamba, Bhekie B.; Msagati, Titus A. M.

    2016-04-01

    This study reports on the water quality index (WQI) of wastewater and drinking water in the Mpumalanga and North West provinces of South Africa. The WQI is one of the most effective tools available to water sustainability researchers, because it provides an easily intelligible ranking of water quality on a rating scale from 0 to 100, based on the ascription of different weightings to several different parameters. In this study the WQI index ratings of wastewater and drinking water samples were computed according to the levels of pH, electrical conductivity (EC), biochemical oxygen demand (BOD), E. coli, temperature, turbidity and nutrients (nitrogen and phosphates) found in water samples collected from the two provinces between June and December, 2014. This study isolated three groups of WQ-rated waters, namely: fair (with a WQI range = 32.87-38.54%), medium (with a WQI range = 56.54-69.77%) and good (with a WQI range = 71.69-81.63%). More specifically, 23%, 23% and 54% of the sampled sites registered waters with fair, medium and good WQ ratings respectively. None of the sites sampled during the entire period of the project registered excellent or very good water quality ratings, which would ordinarily indicate that no treatment is required to make it fit for human consumption. Nevertheless, the results obtained by the Eerstehoek and Schoemansville water treatment plants in Mpumalanga and North West provinces, respectively, suggest that substantial improvement in the quality of water samples is possible, since the WQI values for all of the treated samples were higher than those for raw water. Presence of high levels of BOD, low levels of dissolved oxygen (DO), E. coli, nitrates and phosphates especially in raw water samples greatly affected their overall WQ ratings. It is recommended that a point-of-use system should be introduced to treat water intended for domestic purposes in the clean-water-deprived areas.

  14. CNA Small Group Discussion: Aiding Cameroon’s Effort to Counter Boko Haram

    Science.gov (United States)

    2015-02-18

    important to understand that the modern (“ colonial ”) borders dividing the Lake Chad Basin region mean little to Boko Haram (and indeed to many...Cameroon is an important partner to the U.S. in Africa , and the two have cooperated on issues including economic development, public health, and...work with its neighbors to counter the threat and prevent its spread within Africa . One participant noted that, like the government of Nigeria, the

  15. Nitrogen Oxide biogenic emissions from soils: impact on NOx and ozone formation in West Africa during AMMA (African Monsoon Multidisciplinary Analysis)

    OpenAIRE

    2007-01-01

    International audience; Nitrogen Oxide biogenic emissions from soils are driven by soil and environmental parameters. The relationship between these parameters and NO fluxes is highly non linear. A new algorithm, based on a neural network calculation, is used to reproduce the NO biogenic emissions in West Africa during the AMMA campaign, in August 2006. It has been coupled in the surface scheme of a coupled chemistry dynamics model to estimate the impact of the NO emissions on NOx and O3 form...

  16. The landscape configuration of zoonotic transmission of Ebola virus disease in West and Central Africa: interaction between population density and vegetation cover

    OpenAIRE

    Michael G Walsh; MA Haseeb

    2015-01-01

    Ebola virus disease (EVD) is an emerging infectious disease of zoonotic origin that has been responsible for high mortality and significant social disruption in West and Central Africa. Zoonotic transmission of EVD requires contact between susceptible human hosts and the reservoir species for Ebolaviruses, which are believed to be fruit bats. Nevertheless, features of the landscape that may facilitate such points of contact have not yet been adequately identified. Nor have spatial dependencie...

  17. Assessing the impact of climate variability and climate change on runoff in West Africa: The case of Senegal and Nakambe River basins

    OpenAIRE

    Karambiri, H; García Galiano, S.G.; Giraldo, J.D.; Yacouba, H.; Ibrahim, B.; Barbier, B.; Polcher, J.

    2011-01-01

    International audience; West Africa and its people are very vulnerable to climate variability and changes. Increasing the knowledge of plausible trends of rainfall dry spell lengths (DSL) in the rainy season, and of runoff, enables the assessment of vulnerability and adaptive capacity of the system. These predictions are crucial from a water management and policy perspective. The analyses based on regional climate models (RCMs) and observed datasets exhibit non-stationary behavior and an incr...

  18. Climate scenarios for semi-arid and sub-humid regions. A comparison of climate scenarios for the dryland regions, in West Africa from 1990 to 2050

    OpenAIRE

    van den Born GJ; Schaeffer M; Leemans R; NOP

    2001-01-01

    The identification of climate scenarios for dryland areas in Sub-Saharan West Africa is part of a project to assess the impact of climate change on water availability, agriculture and food security in drylands (ICCD-project). The project is financed by Netherlands Research Programme on Global Air Pollution and Climate Change (NRP) and part of theme 'Vulnerability of Natural and Social Systems for Climate'. The report describes the development and description of climate scenarios by ...

  19. Insecticide resistance in Bemisia tabaci Gennadius (Homoptera : Aleyrodidae) and Anopheles gambiae Giles (Diptera : Culicidae) could compromise the sustainability of malaria vector control strategies in West Africa

    OpenAIRE

    2013-01-01

    Insecticides from the organophosphate (OP) and pyrethroid (PY) chemical families, have respectively, been in use for 50 and 30 years in West Africa, mainly against agricultural pests, but also against vectors of human disease. The selection pressure, with practically the same molecules year after year (mainly on cotton), has caused insecticide resistance in pest populations such as Bemisia tabaci, vector of harmful phytoviruses on vegetables. The evolution toward insec