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Sample records for africa west africa

  1. West Africa

    NASA Technical Reports Server (NTRS)

    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

  2. West and Central Africa.

    PubMed

    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.

  3. Drought in West Africa

    NASA Technical Reports Server (NTRS)

    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.

  4. Drought in West Africa

    NASA Technical Reports Server (NTRS)

    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.

  5. Ebola in West Africa.

    PubMed

    Raka, Lul; Guardo, Monica

    2015-03-15

    Ebola viral disease (EVD) is a severe and life-threatening disease. The current Ebola outbreak in West Africa entered its second year and is unprecedented because it is the largest one in history, involved urban centers and affected a large number of health care workers. It quickly escalated from medical into a humanitarian, social, economic, and security crisis. The primary pillars to prevent EVD are: early diagnosis, isolation of patients, contact tracing and monitoring, safe burials, infection prevention and control and social mobilization. The implementation of all these components was challenged in the field. Key lessons from this Ebola outbreak are that countries with weak health care systems can't withstand the major outbreaks; preparedness to treat the first confirmed cases is a national emergency; all control measures must be coordinated together and community engagement is the great factor to combat this disease.

  6. Ebola in West Africa

    PubMed Central

    Raka, Lul; Guardo, Monica

    2015-01-01

    Ebola viral disease (EVD) is a severe and life-threatening disease. The current Ebola outbreak in West Africa entered its second year and is unprecedented because it is the largest one in history, involved urban centers and affected a large number of health care workers. It quickly escalated from medical into a humanitarian, social, economic, and security crisis. The primary pillars to prevent EVD are: early diagnosis, isolation of patients, contact tracing and monitoring, safe burials, infection prevention and control and social mobilization. The implementation of all these components was challenged in the field. Key lessons from this Ebola outbreak are that countries with weak health care systems can’t withstand the major outbreaks; preparedness to treat the first confirmed cases is a national emergency; all control measures must be coordinated together and community engagement is the great factor to combat this disease. PMID:27275217

  7. Endoscopic capacity in West Africa.

    PubMed

    Perl, Daniel; Leddin, Desmond; Bizos, Damon; Veitch, Andrew; N'Dow, James; Bush-Goddard, Stephanie; Njie, Ramou; Lemoine, Maud; Anderson, Suzanne T; Igoe, John; Anandasabapathy, Sharmila; Shah, Brijen

    2016-03-01

    Levels of endoscopic demand and capacity in West Africa are unclear. This paper aims to: 1. describe the current labor and endoscopic capacity, 2. quantify the impact of a mixed-methods endoscopy course on healthcare professionals in West Africa, and 3. quantify the types of diagnoses encountered. In a three-day course, healthcare professionals were surveyed on endoscopic resources and capacity and were taught through active observation of live cases, case discussion, simulator experience and didactics. Before and after didactics, multiple-choice exams as well as questionnaires were administered to assess for course efficacy. Also, a case series of 23 patients needing upper GI endoscopy was done. In surveying physicians, less than half had resources to perform an EGD and none could perform an ERCP, while waiting time for emergency endoscopy in urban populations was at least one day. In assessing improvement in medical knowledge among participants after didactics, objective data paired with subjective responses was more useful than either alone. Of 23 patients who received endoscopy, 7 required endoscopic intervention with 6 having gastric or esophageal varices. Currently the endoscopic capacity in West Africa is not sufficient. A formal GI course with simulation and didactics improves gastrointestinal knowledge amongst participants.

  8. Africa.

    ERIC Educational Resources Information Center

    Martz, Carlton

    2001-01-01

    This publication explores issues related to Africa. It examines the U.S. response to the Barbary pirate states (Morocco, Algiers, Tunis, Tripoli) in the early 19th century; the current AIDS crisis in Africa; and 14th century Mali and other Islamic lands through the eyes of Ibn Battuta, who traveled throughout the Muslim world. Each article…

  9. Africa.

    ERIC Educational Resources Information Center

    Happel, Sue; Loeb, Joyce

    Although the activities in this unit are designed primarily for students in the intermediate grades, the document's text, illustrations, and bibliographic references are suitable for anyone interested in learning about Africa. Following a brief introduction and map work, the document is arranged into six sections. Section 1 traces Africa's history…

  10. Africa.

    ERIC Educational Resources Information Center

    Happel, Sue; Loeb, Joyce

    Although the activities in this unit are designed primarily for students in the intermediate grades, the document's text, illustrations, and bibliographic references are suitable for anyone interested in learning about Africa. Following a brief introduction and map work, the document is arranged into six sections. Section 1 traces Africa's history…

  11. Melioidosis Imported from West Africa to Europe

    PubMed Central

    Cuadros, Juan; Gil, Horacio; Miguel, Julio De; Marabé, Graciela; Gómez-Herruz, Teresa Arroyo Peña; Lobo, Bruno; Marcos, Ruth; Anda, Pedro

    2011-01-01

    We report the first case of imported melioidosis in Spain from a diabetic immigrant who visited West Africa during the rainy season. Because of the unusual presentation of this disease in Africa, clinical and microbiological diagnosis of imported melioidosis from this continent can be very elusive. PMID:21813848

  12. Namibia [South-West Africa].

    PubMed

    1983-01-01

    Namibia, a country of 1,051,700 inhabitants of whom 85.6% are blacks of diverse ethnic and linguistic origins, 7.5% are white, and the rest are of mixed ancestry, has been illegally administered by South Africa since 1966, when a League of Nations mandate was revoked by the UN. The Namibian Desert was a barrier to European expansion until the late 18th century, when the area came under German and British influence. Efforts to bring about an orderly and peaceful transition to independent status are hampered at present by the lack of parallel progress toward withdrawal of Cuban combat forces from Angola. Beginning in 1980, considerable executive power was transferred from the administrator general appointed by the South African Government to an interim 3-tier system of elected representatives dividing responsibility between central, ethnic, and local authorities. The judicial structure has separate overlapping systems for whites, westernized blacks and coloreds and for indigenous blacks. Namibian society is highly politicized, with 4 white and about 40 nonwhite political groups. The South West Africa People's Organization (SWAPO) remains an active party inside Namibia despite simultaneous detention of its entire leadership in 1979 by the South African Government. Namibia's economy is dual, with a modern market sector of mining, ranching and fishing producing most of the wealth and a traditional subsistence sector supporting most of the labor force. About 60% of the work force of 500,000 in 1981 worked in agriculture, 19% in industry and commerce, 6% in mining, 8% in services, and 7% in government. Namibia's gross domestic product in 1980 was $1.712 billion, representing an average growth rate of 2.5% from 1970-80. However, real growth since 1978 has been negative because of persistent drought, political uncertainty, low demand for mineral products, and previous overfishing. Namibia has no separate representation in any international body. The country may have the

  13. Emigration dynamics in West Africa.

    PubMed

    Makinwa-adebusoye, P K

    1995-01-01

    This report on the emigration dynamics at work in Western Africa opens by noting that this region comprises an important migration system with large legal and illegal movements of people within the region and to industrialized countries. Migration has been fueled by high growth rates coupled with lower growth rates of per capital income. Migration takes the form of continuing inflow into receiving countries, such as the Ivory Coast, sudden changes in migration status (in Ghana and Nigeria) reflecting sudden economic changes, a brain drain to developed countries, and an influx of refugees. The second section of the report presents a brief look at historical migratory patterns, including those of nomads which continue today. Data limitations are addressed in section 3, and the drawbacks of census data for migration information are noted. The next section describes the economic and demographic factors in the region which contribute to migration. These include the long lasting effects of colonization in general, the exploitation of minerals, patterns of agricultural development, poverty, and population growth. A closer examination of these forces at work is provided in case studies of Ghana, Nigeria, and the migration stream from Burkina Faso to the Ivory Coast. Section 5 looks at the economic causes and effects of the brain drain. Social and cultural factors are covered in section 6, with an emphasis placed on family and migration networks. Section 7 covers political factors influencing migration, such as the efforts of people to retain contact with other members of their ethnic group who may live on the opposite side of an arbitrarily drawn (by colonizers) international border, the designation of administrative capital cities, and the ease in crossing borders without documentation. The next section describes the 1975 formation of the Economic Community for West Africa (ECOWAS) and its protocols regarding free movement of citizens within the states which comprise the

  14. Peacekeeping Operations in West Africa

    DTIC Science & Technology

    2000-04-01

    Africa 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 6. AUTHOR (S) 5d. PROJECT NUMBER 5e. TASK NUMBER 5f. WORK UNIT NUMBER 7...are those of the author and do not reflect the official policy or position of the US government or the Department of Defense. In accordance with Air...1 DEFINITON OF — PEACEKEEPING OPERATIONS

  15. Narco-Pipeline to West Africa

    DTIC Science & Technology

    2009-04-01

    Democracy and Promoting Social Development, provides an avenue of analysis on how these elements and lessons learned can be exported to West Africa...Colombia……………………………………………………………..25 Strategy for Strengthening Democracy and Promoting Social Development…………...31 Nationalism... social and economic development. “In West Africa, the average Human Development Index (HDI) ranking is 2.3 times poorer than South America.”22 The

  16. Mastomys natalensis and Lassa fever, West Africa.

    PubMed

    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.

  17. Transcending Communication Barriers with West Africa.

    ERIC Educational Resources Information Center

    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…

  18. Epidemiology: Malaria in a warmer West Africa

    NASA Astrophysics Data System (ADS)

    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.

  19. West Africa land use and land cover time series

    USGS Publications Warehouse

    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.

  20. Lassa fever: another threat from West Africa.

    PubMed

    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.

  1. Problem of hepatocellular carcinoma in West Africa

    PubMed Central

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

    2014-01-01

    The incidence of hepatocellular carcinoma (HCC) is known to be high in West Africa with an approximate yearly 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 poorly-managed 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. PMID:25429316

  2. Storage facility completed off West Africa

    SciTech Connect

    Not Available

    1992-06-29

    This paper reports that Cabinda Gulf Oil Co. Ltd.'s Takula storage project has been completed off West Africa. Oil began flowing May 1 through a newly constructed offshore and land pipeline, marking the project's completion. The company also installed 3 miles of onshore distribution pipe up to 42 in., modified existing manifolds, installed loading pumps, and performed other civil engineering work ashore. The company says the $93 million contract was the largest in OPI's 7-year history.

  3. Simulation of Rainfall Variability Over West Africa

    NASA Astrophysics Data System (ADS)

    Bader, J.; Latif, M.

    The impact of sea surface temperature (SST) and vegetation on precipitation over West Africa is investigated with the atmospheric general circulation model ECHAM4.x/T42. Ensemble experiments -driven with observed SST- show that At- lantic SST has a significant influence on JJA precipitation over West Africa. Four- teen experiments were performed in which the climatological SST was enhanced or decreased by one Kelvin in certain ocean areas. Changing SST in the eastern tropi- cal Atlantic only caused significant changes along the Guinea Coast, with a positive SSTA increasing rainfall and a negative reducing it. The response was nearly linear. Changing SST in other ocean areas caused significant changes over West Africa, es- pecially in the Sahel area. The response is found to be non linear, with only negative SSTA leading to significant reduction in Sahel rainfall. Also, the impact of the SSTAs from the different ocean regions was not additive with respect to the rainfall. Four simulations with a coupled model (the simple dynamic vegetation model (SVege) and the ECHAM4-AGCM were coupled) were also performed, driven with observed SST from 1945 to 1998. The standard ECHAM-AGCM -forced by the same observed SST- was able to reproduce the drying trend from the fifties to the mid-eighties in the Sahel, but failed to mirror the magnitude of the rainfall anomalies. The coupled model was not only able to reproduce this drying trend, but was also able to better reproduce the amplitudes of the rainfall anomalies. The dynamic vegetation acted like an amplifier, increasing the SST induced rainfall anomalies.

  4. Niobium content of soils from West Africa

    USGS Publications Warehouse

    Grimaldi, F.S.; Berger, I.A.

    1961-01-01

    Analysis of twenty lateritic soil samples from West Africa has shown them to contain an average 24 p.p.m. of niobium; four similar samples taken from within a few miles from a niobium deposit contain from 79 to 87 p.p.m. niobium. It has been shown that as the aluminum content of the soils increases, the following depletion sequence is obtained: Si > Nb > Al = Fe The data indicate that, in general, high enrichments of niobium are not to be expected in lateritic soils. ?? 1961.

  5. West Africa’s War on Terrorism: Time and Patience

    DTIC Science & Technology

    2009-03-25

    National Defense University, November 15-16, 2005, Fort Lesley J. McNair, Washington, DC, 5. 59 Kevin A. O ’ Brien and Theodore Karasik, “Case Study...II, Empirical Findings,” 249. 63 Ibid. 64 Ibid. 65 O ’ Brien , “Case Study: West Africa.” 66 Akosah-Sarpong, Kofi, “Commentary: West Africa’s Military...67 O ’ Brien , “Case Study: West Africa,” 249. 68 McGowan, “Coups and Conflict in West Africa, 1955-2004: Part II, Empirical Findings,” 248. 69 Reuven

  6. Strategies for containing Ebola in West Africa.

    PubMed

    Pandey, Abhishek; Atkins, Katherine E; Medlock, Jan; Wenzel, Natasha; Townsend, Jeffrey P; Childs, James E; Nyenswah, Tolbert G; Ndeffo-Mbah, Martial L; Galvani, Alison P

    2014-11-21

    The ongoing Ebola outbreak poses an alarming risk to the countries of West Africa and beyond. To assess the effectiveness of containment strategies, we developed a stochastic model of Ebola transmission between and within the general community, hospitals, and funerals, calibrated to incidence data from Liberia. We find that a combined approach of case isolation, contact-tracing with quarantine, and sanitary funeral practices must be implemented with utmost urgency in order to reverse the growth of the outbreak. As of 19 September, under status quo, our model predicts that the epidemic will continue to spread, generating a predicted 224 (134 to 358) daily cases by 1 December, 280 (184 to 441) by 15 December, and 348 (249 to 545) by 30 December.

  7. Marriage in West Africa--A Composite. Mini-Module.

    ERIC Educational Resources Information Center

    African-American Inst., New York, NY. School Services Div.

    This module contains a description of the responsibilities and ceremony of marriage in west Africa, seven discussion questions exploring the differences between Western and African marriage customs, five enrichment activities, and a bibliography of five books about love and marriage in Africa. The general discussion relates the engagement of a…

  8. Marriage in West Africa--A Composite. Mini-Module.

    ERIC Educational Resources Information Center

    African-American Inst., New York, NY. School Services Div.

    This module contains a description of the responsibilities and ceremony of marriage in west Africa, seven discussion questions exploring the differences between Western and African marriage customs, five enrichment activities, and a bibliography of five books about love and marriage in Africa. The general discussion relates the engagement of a…

  9. Case report: melioidosis imported from West Africa to Europe.

    PubMed

    Cuadros, Juan; Gil, Horacio; Miguel, Julio De; Marabé, Graciela; Gómez-Herruz, Teresa Arroyo Peña; Lobo, Bruno; Marcos, Ruth; Anda, Pedro

    2011-08-01

    We report the first case of imported melioidosis in Spain from a diabetic immigrant who visited West Africa during the rainy season. Because of the unusual presentation of this disease in Africa, clinical and microbiological diagnosis of imported melioidosis from this continent can be very elusive.

  10. West Africa prepares for busy season. [Petroleum exploration in West Africa

    SciTech Connect

    Not Available

    1982-06-20

    Although there has been a decrease in oil prices, activity along coastal West Africa has tended to increase, with emphasis on field development and production. Because of a world-wide surplus of petroleum, Nigeria has had to cut production by more than half and offshore operations have been affected also. Off the coast of Gabon exploration activity has increased with numerous wildcat rigs which are potentially highly productive. Overall production in Gabon has decreased slightly since 1980. The People's Republic of the Congo, on the other hand, has increased productivity due to new successful fields, while in the Angola/Cabinda area new offshore programs are forming. Production and exploration increases are also expected for Ghana, Zaire, Cameroon, and South Africa. (JBF)

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

    NASA Technical Reports Server (NTRS)

    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.

  12. Shared decision making in West Africa: The forgotten area.

    PubMed

    Diouf, Ndeye Thiab; Ben Charif, Ali; Adisso, Lionel; Adekpedjou, Rhéda; Zomahoun, Hervé Tchala Vignon; Agbadjé, Titilayo Tatiana; Dogba, Mama Joyce; Garvelink, Mirjam Marjolein

    2017-06-01

    Up to now, little attention has been paid to West Africa when it comes to shared decision making (SDM). West African countries seem to lag behind with regard to SDM initiatives compared to many other countries in the world. There is some interest in informed decision making or informed consent, but little in a full SDM process. Few decision-making tools are available for healthcare professionals and the majority are not designed to support decision-making with patients. Furthermore, to the best of our knowledge, there are no training programs for implementing SDM in healthcare teams. Many barriers exist to implementing SDM in West Africa, including lack of options, few or poor health resources and low levels of education. However, African countries present many opportunities for SDM as well. Existing SDM innovations developed for other populations with low literacy could be explored and adapted to the West African context, and research on implementation and outcomes in West Africa could contribute to SDM worldwide. West African countries are in an excellent position to both learn from other countries and contribute to SDM development in other parts of the world. In this paper we reflect on SDM challenges and opportunities, and propose a research agenda for West Africa. We hope to awaken interest in SDM in West Africa and encourage future collaborations on SDM with various West African stakeholders, including patients, healthcare professionals, policymakers, non-government organisations (NGOs) and academic institutions. Copyright © 2017. Published by Elsevier GmbH.

  13. Ancient west Eurasian ancestry in southern and eastern Africa

    PubMed Central

    Pickrell, Joseph K.; Patterson, Nick; Loh, Po-Ru; Lipson, Mark; Berger, Bonnie; Stoneking, Mark; Pakendorf, Brigitte; Reich, David

    2014-01-01

    The history of southern Africa involved interactions between indigenous hunter–gatherers and a range of populations that moved into the region. Here we use genome-wide genetic data to show that there are at least two admixture events in the history of Khoisan populations (southern African hunter–gatherers and pastoralists who speak non-Bantu languages with click consonants). One involved populations related to Niger–Congo-speaking African populations, and the other introduced ancestry most closely related to west Eurasian (European or Middle Eastern) populations. We date this latter admixture event to ∼900–1,800 y ago and show that it had the largest demographic impact in Khoisan populations that speak Khoe–Kwadi languages. A similar signal of west Eurasian ancestry is present throughout eastern Africa. In particular, we also find evidence for two admixture events in the history of Kenyan, Tanzanian, and Ethiopian populations, the earlier of which involved populations related to west Eurasians and which we date to ∼2,700–3,300 y ago. We reconstruct the allele frequencies of the putative west Eurasian population in eastern Africa and show that this population is a good proxy for the west Eurasian ancestry in southern Africa. The most parsimonious explanation for these findings is that west Eurasian ancestry entered southern Africa indirectly through eastern Africa. PMID:24550290

  14. Ancient west Eurasian ancestry in southern and eastern Africa.

    PubMed

    Pickrell, Joseph K; Patterson, Nick; Loh, Po-Ru; Lipson, Mark; Berger, Bonnie; Stoneking, Mark; Pakendorf, Brigitte; Reich, David

    2014-02-18

    The history of southern Africa involved interactions between indigenous hunter-gatherers and a range of populations that moved into the region. Here we use genome-wide genetic data to show that there are at least two admixture events in the history of Khoisan populations (southern African hunter-gatherers and pastoralists who speak non-Bantu languages with click consonants). One involved populations related to Niger-Congo-speaking African populations, and the other introduced ancestry most closely related to west Eurasian (European or Middle Eastern) populations. We date this latter admixture event to ∼900-1,800 y ago and show that it had the largest demographic impact in Khoisan populations that speak Khoe-Kwadi languages. A similar signal of west Eurasian ancestry is present throughout eastern Africa. In particular, we also find evidence for two admixture events in the history of Kenyan, Tanzanian, and Ethiopian populations, the earlier of which involved populations related to west Eurasians and which we date to ∼2,700-3,300 y ago. We reconstruct the allele frequencies of the putative west Eurasian population in eastern Africa and show that this population is a good proxy for the west Eurasian ancestry in southern Africa. The most parsimonious explanation for these findings is that west Eurasian ancestry entered southern Africa indirectly through eastern Africa.

  15. Phytoplankton off the West Coast of Africa

    NASA Technical Reports Server (NTRS)

    2002-01-01

    Just off the coast of West Africa, persistent northeasterly trade winds often churn up deep ocean water. When the nutrients in these deep waters reach the ocean's surface, they often give rise to large blooms of phytoplankton. This image of the Mauritanian coast shows swirls of phytoplankton fed by the upwelling of nutrient-rich water. The scene was acquired by the Medium Resolution Imaging Spectrometer (MERIS) aboard the European Space Agency's ENVISAT. MERIS will monitor changes in phytoplankton across Earth's oceans and seas, both for the purpose of managing fisheries and conducting global change research. NASA scientists will use data from this European instrument in the Sensor Intercomparison and Merger for Biological and Interdisciplinary Oceanic Studies (SIMBIOS) program. The mission of SIMBIOS is to construct a consistent long-term dataset of ocean color (phytoplankton abundance) measurements made by multiple satellite instruments, including the Sea-viewing Wide Field-of-view Sensor (SeaWiFS) and the Moderate-Resolution Imaging Spectroradiometer (MODIS). For more information about MERIS and ENVISAT, visit the ENVISAT home page. Image copyright European Space Agency

  16. Sustainability of groundwater in Mali, West Africa

    NASA Astrophysics Data System (ADS)

    Lutz, Alexandra; Thomas, James M.; Pohll, Greg; Keita, Mamadou; McKay, W. Alan

    2009-10-01

    The following paper describes the goals and some preliminary work in the Bani sustainability study, an ongoing project in Mali, West Africa. Rural communities in Mali are increasingly relying on hand-pumps, which tap groundwater resources, as a means of obtaining potable water. The long-term sustainable yield of groundwater resources is not known but can be evaluated in sustainability study. In 2005, a groundwater sustainability study was established along the Bani River of Mali. The Bani study collected groundwater levels that were used in a conceptual groundwater flow model—the Bani model—to develop an understanding of current aquifer conditions and to make limited predictions of sustainability under various future scenarios. The Bani model showed the climatic parameters of recharge (derived from precipitation) and evapotranspiration to influence simulated groundwater levels and groundwater volume available, while increased pumping rates, due to population growth, showed little effect. When considered in the context of the actual Bani sustainability study area, the change in groundwater levels resulting from climatic parameters may have negative implications, especially during several consecutive years of decreased precipitation, such as drought, or if downward trends anticipated for precipitation continue.

  17. Phytoplankton off the West Coast of Africa

    NASA Technical Reports Server (NTRS)

    2002-01-01

    Just off the coast of West Africa, persistent northeasterly trade winds often churn up deep ocean water. When the nutrients in these deep waters reach the ocean's surface, they often give rise to large blooms of phytoplankton. This image of the Mauritanian coast shows swirls of phytoplankton fed by the upwelling of nutrient-rich water. The scene was acquired by the Medium Resolution Imaging Spectrometer (MERIS) aboard the European Space Agency's ENVISAT. MERIS will monitor changes in phytoplankton across Earth's oceans and seas, both for the purpose of managing fisheries and conducting global change research. NASA scientists will use data from this European instrument in the Sensor Intercomparison and Merger for Biological and Interdisciplinary Oceanic Studies (SIMBIOS) program. The mission of SIMBIOS is to construct a consistent long-term dataset of ocean color (phytoplankton abundance) measurements made by multiple satellite instruments, including the Sea-viewing Wide Field-of-view Sensor (SeaWiFS) and the Moderate-Resolution Imaging Spectroradiometer (MODIS). For more information about MERIS and ENVISAT, visit the ENVISAT home page. Image copyright European Space Agency

  18. Combating Narco-Terrorism in West Africa

    DTIC Science & Technology

    2012-06-15

    European market. Weq Africa i~ located approximately 4,000 mile" away. ac ros rhc Atlatllic. from the cocoa fields of South America making the region an...value of regional cooperation and arc poi ed and read) In benefit from lJSAFRlCOM engagement. Last fall. Gambia ho ... ted a regional forum on illegal...Panner!:.hip for Global Securi ty in A frica: Hearing before Subcornmiuce on Africa, Global Health . and Human Right~ . .J uly 6, 20 II . lllt p:l

  19. First carboniferous conulariids from Niger (west Africa)

    NASA Astrophysics Data System (ADS)

    Babcock, L. E.; Lang, J.; Yahaya, M.

    1995-01-01

    Two new conulariid species, Paraconularia feldmanni sp. nov. and P. sahara sp. nov., are described from the Lower Carboniferous (Visean) Talak Formation of northern Niger. These are the first example of the genus Paraconularia to be reported from Africa and the first Carboniferous conulariids from that continent to be assigned to species level. Previously reported Carboniferous conulariids from Africa were collected from Morocco, assigned to other genera, and left in open nomenclature. Paraconularia is interpreted to have been cosmopolitan by the Early Carboniferous, and is the dominant genus in most assemblages of Carboniferous conulariids.

  20. Mapping and analyzing urban growth in West Africa

    NASA Astrophysics Data System (ADS)

    Adhikari, P.; de Beurs, K. M.

    2014-12-01

    Africa has experienced the highest urban growth (~3.5% per year) in the developing world. West Africa in particular has seen significant urban growth mainly driven by the high natural population growth rate and the increasing percentage of population moving to urban areas. Urban growth in West Africa is expected to continue in decades to come. This study uses Landsat data at five different time steps (1970, 1980, 1990, 2000, and 2010) to map four cities from four different eco-regions of West Africa since the early 1970s. The selected four cities, Kumasi in Ghana, Abuja in Nigeria, Tahoua in Niger and Ouagadoughou in Burkina Faso, are some of the fastest growing cities in the region. We selected the cities in the following ecoregions: Eastern Guinean Forest, Guinean Forest-Savanna Mosaic, Sahelian Acacia Savanna and West Sudanian Savanna. We hypothesize that urban growth in West Africa is different compared to the other parts of the world primarily due to the dependency of about 60 percent of active labor force on subsistence agriculture in the region. As agriculture productivity is dependent on favorable climatic conditions (i.e., good rainfall, suitable temperature), any variability in climate impends the livelihood of subsistence farmers triggering the movements of more people towards the cities. Therefore, studying urban growth based on ecoregions help to better explain the urban development in West Africa. After mapping the urban areas, this study makes a comparative analysis of the temporal and spatial pattern of the urban growths across the ecoregions in West Africa.

  1. Glory over clouds off West Africa

    NASA Image and Video Library

    2017-09-27

    On April 23, 2013 NASA’s Terra satellite passed off the coast of West Africa, allowing the Moderate Resolution Imaging Spectroradiometer (MODIS) flying aboard to capture a curious phenomenon over the cloud deck below. The rainbow-like discoloration that can be seen streaking across the bank of marine cumulus clouds near the center of this image is known as a “glory”. A glory is caused by the scattering of sunlight by a cloud made of water droplets that are all roughly the same size, and is only produced when the light is just right. In order for a glory to be viewed, the observer’s anti-solar point must fall on the cloud deck below. In this case the observer is the Terra satellite, and the anti-solar point is where the sun is directly behind you – 180° from the MODIS line of sight. Water and ice particles in the cloud bend the light, breaking it into all its wavelengths, and the result is colorful flare, which may contain all of the colors of the rainbow. Credit: NASA/GSFC/Jeff Schmaltz/MODIS Land Rapid Response Team NASA image use policy. NASA Goddard Space Flight Center enables NASA’s mission through four scientific endeavors: Earth Science, Heliophysics, Solar System Exploration, and Astrophysics. Goddard plays a leading role in NASA’s accomplishments by contributing compelling scientific knowledge to advance the Agency’s mission. Follow us on Twitter Like us on Facebook Find us on Instagram

  2. Four rigs refurbished for West Africa drilling

    SciTech Connect

    Not Available

    1991-06-10

    In April and May 1990, Shell Petroleum Development Co. of Nigeria Ltd. awarded Noble Drilling West Africa Inc. four separate contracts to drill oil and gas wells in the inland waterways of Nigeria. The contracted rigs included a shallow water jack up, the NN-1, and three posted barges, the Gene Rosser, the Chuck Syring, and the Lewis Dugger. The jack up was built in 1978, and the three posted barges are 1980s vintage. Three of the rigs have been idle for a number of years. The Shell Nigeria contracts required major modifications to the rigs before putting them into international service. Noble replaced or refurbished all major pieces of equipment in the drilling, power, and service systems on the rigs. Rig crews serviced all other equipment. A significant amount of general service piping and electrical wiring was replaced. Each rig also required additional motor control centers to support the new drilling and mud processing equipment. Alfa-Laval waste-heat water desalination plants and new sewage treatment units were installed on all four rigs. Because of the tidal variances and high silt conditions expected in the African waterways, all engine cooling systems were converted from heat exchangers to radiators. Rotary tables were made common on all rigs at 37 1/2 in. Noble had all traveling equipment completely inspected and modified as necessary. Strict attention was paid to certification and documentation of all equipment. Safety upgrades conformed to both Shell and Noble standards. Fire and gas detection systems were installed throughout each rig. Water and foam deluge systems were installed in the wellhead areas, and new foam systems and monitors were installed on the helldecks.

  3. Kimberlites of the Man craton, West Africa

    NASA Astrophysics Data System (ADS)

    Skinner, E. M. W.; Apter, D. B.; Morelli, C.; Smithson, N. K.

    2004-09-01

    The Man craton in West Africa is an Archaean craton formerly joined to the Guyana craton (South America) that was rifted apart in the Mesozoic. Kimberlites of the Man craton include three Jurassic-aged clusters in Guinea, two Jurassic-aged clusters in Sierra Leone, and in Liberia two clusters of unknown age and one Neoproterozoic cluster recently dated at ˜800 Ma. All of the kimberlites irrespective of age occur as small pipes and prolific dykes. Some of the Banankoro cluster pipes in Guinea, the Koidu pipes in Sierra Leone and small pipes in the Weasua cluster in Liberia contain hypabyssal-facies kimberlite and remnants of the so-called transitional-facies and diatreme-facies kimberlite. Most of the Man craton kimberlites are mineralogically classified as phlogopite kimberlites, although potassium contents are relatively low. They are chemically similar to mica-poor Group 1A Southern African examples. The Jurassic kimberlites are considered to represent one province of kimberlites that track from older bodies in Guinea (Droujba 153 Ma) to progressively younger kimberlites in Sierra Leone (Koidu, 146 Ma and Tongo, 140 Ma). The scarcity of diatreme-facies kimberlites relative to hypabyssal-facies kimberlites and the presence of the so-called transitional-facies indicate that the pipes have been eroded down to the interface between the root and diatreme zones. From this observation, it is concluded that extensive erosion (1-2 km) has occurred since the Jurassic. In addition to erosion, the presence of abundant early crystallizing phlogopite is considered to have had an effect on the relatively small sizes of the Man craton kimberlites.

  4. Counterinsurgency in West Africa: Non Lethal Activities

    DTIC Science & Technology

    2009-06-01

    Washington Headquarters Services, Directorate for Information Operations and Reports (0704-0188), 1215 Jefferson Davis Highway, Suite 1204, Arlington...2009). 3 Department of the Army, Field Manual (FM ) 3-24, Counterinsurgency ( Washington , DC: Government Printing Office, December 2006) 4 Ibid. 5...Understanding Civil War: volume 1 Africa ( Washington , DC: World Bank, 2005), 250. 18 Diop, 196. 19 African Research Group, The Casamance Conflict 1982

  5. [Familial modernity and plurality in West Africa].

    PubMed

    Vimard, P

    1993-01-01

    Changes in the family system of West Africa have accompanied the numerous economic, demographic, and social changes occurring after colonization and especially since independence. This work uses monographic data from Togo and the Ivory Coast to examine to what degree lineage structures have been supplanted by autonomy of domestic groups and the emergence of new forms of family organization, to what extent intrafamilial social relations and behavior have been affected by the market economy, and whether the spread of western culture has led to a plurality of family models. The integration of rural African societies into market economies has been achieved primarily through their progressive absorption into plantation economic systems. Appropriation of manpower by plantation economies has largely removed control over the reproduction and use of the labor force from the lineage to a smaller family group. Individual relationships are undergoing redefinition within the new structures of socially and economically autonomous domestic groups. Lineages have lost control over matrimonial alliances; marriage has ceased to represent an exchange between social groups and has become an alliance between individuals. The weakened integration of couples into traditional family structures has increased the instability of unions. The emergence of the domestic group as an autonomous institution has engendered a redefinition of roles and practices within families, and new forms of social relations between the husbands, wives, and their children. Economic and social roles today depend less on belonging to extended structures such as lineages or age classes and more on nonpredetermined factors susceptible to change that characterize the family and economic position, such as educational level, marital status, and occupation. Changes in power relations between spouses have led to greater independence but also greater precariousness in women;s positions. The status of children has undergone a

  6. The lion in West Africa is critically endangered.

    PubMed

    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 <35,000 individuals occupying 25% of its historic range. The situation is most critical for the geographically isolated populations in West Africa, where the species is considered regionally endangered. Elevating their conservation significance, recent molecular studies establish the genetic distinctiveness of West and Central African 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 <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

  7. The Lion in West Africa Is Critically Endangered

    PubMed Central

    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 <35,000 individuals occupying 25% of its historic range. The situation is most critical for the geographically isolated populations in West Africa, where the species is considered regionally endangered. Elevating their conservation significance, recent molecular studies establish the genetic distinctiveness of West and Central African 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 <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

  8. Regional paleogeographic evolution of west Africa: Implications for hydrocarbon exploration

    SciTech Connect

    Hempton, M.R.; Rosen, M.A.; Coughlin, R.M.; Scardina, A.D.; Hagen, E.S.; Nordstrom, P.J. )

    1991-03-01

    New paleogeographic reconstructions of west African continental margins provide a regional framework to contrast differences in hydrocarbon habitat and tectonostratigraphic style. Five regional provinces are delineated: (1) Northwest Africa margin from mauritania to Sierra Leone, (2) Transform margin from Liberia to Benin, (3) Niger delta of Nigeria, Cameroon, and Equatorial Guinea, (4) South Atlantic Salt basin margin from Cameroon to Angola, and (5) Southwest Africa margin of Namibia and South Africa. Computer-constrained paleogeographic reconstructions based on exploration data depict the separation of west Africa from South and North America during the Late Triassic to the present along three rift systems. In northwest Africa rifting began in the Late Triassic associated with the opening of the Central Atlantic. In southwest Africa rifting began between the southern tips of Africa and South America in the Early Cretaceous (Valanginian) and propagated northward to the Benue Trough, a broad zone of left-lateral shear and extensional basins that began to open in the Aptian. Between these two rift systems, the Transform margin rift system initiated in the Early Cretaceous (Barremain) as a wrench-fault dominated eastward extension of the Proto-Caribbean ocean that propagated to the Benue Trough by the middle Albian. The most important variables affecting the tectonostratigraphic and hydrocarbon evolution of the west African margins include (1) the geometry, kinematics, and duration of rifting; (2) distribution of rift basins relative to paleoclimate zones (which affects the deposition of lacustrine source rocks and evaporites while influencing the type and quantity of sediment derived from land); (3) sea-level fluctuations; and (4) distribution of deltaic and turbiditic depocenters.

  9. Regional paleogeographic evolution of West Africa: Implications for hydrocarbon exploration

    SciTech Connect

    Hempton, M.R. )

    1993-11-01

    New paleogeographic reconstructions of west African continental margins provide a regional framework to contrast differences in hydrocarbon habitat and tectonostratigraphic style. The framework consists of five regional provinces: (1) northwest Africa margin from Mauritania to Sierra Leone, (2) transform margin from Libera to Benin, (3) Niger Delta of Nigeria, Cameroon, and equatorial Guinea, (4) South Atlantic Salt Basin margin from Cameroon to Angola, and (5) southwest Africa margin of Namibia and South Africa. Computer-constrained paleogeographic reconstructions based on exploration data depict the separation of west Africa from South and North America along three rift systems during the Late Triassic to the Holocene. In northwest Africa, rifting began in the Late Triassic associated with the opening of the central Atlantic. In southwest Africa, rifting began between the southern tips of Africa and South America in the Early Cretaceous and propagated northward to the Benue trough, a broad zone of left-lateral shear and extensional basins that began to open in the Aptian. Between these two rift systems, the transform margin rift system initiated in the Early Cretaceous (Barremian) as a wrench-fault-dominated eastward extension of the Proto-Caribbean ocean that propagated to the Benue trough by the middle Albian. The most important variables affecting the tectonostratigraphic and hydrocarbon evolution of the west African margins include (1) the geometry, kinematics, and duration of rifting, (2) distribution of rift basins relative to paleoclimate zones (which affects the deposition of lacustrine source rocks and evaporites while influencing the type and quantity of sediment derived from land), (3) sea level fluctuations, and (4) distribution of deltaic and turbiditic depocenters.

  10. Agricultural Adaptations to Climate Changes in West Africa

    NASA Astrophysics Data System (ADS)

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

    2014-12-01

    Agricultural production in West Africa is highly vulnerable to climate variability and change and a fast growing demand for food adds yet another challenge. Assessing possible adaptation strategies of crop production in West Africa under climate change is thus critical for ensuring regional food security and improving human welfare. Our previous efforts have identified as the main features of climate change in West Africa a robust increase in temperature and a complex shift in the rainfall pattern (i.e. seasonality delay and total amount change). Unaddressed, these robust climate changes would reduce regional crop production by up to 20%. In the current work, we use two well-validated crop models (APSIM and SARRA-H) to comprehensively assess different crop adaptation options under future climate scenarios. Particularly, we assess adaptations in both the choice of crop types and management strategies. The expected outcome of this study is to provide West Africa with region-specific adaptation recommendations that take into account both climate variability and climate change.

  11. Child Trafficking in West Africa: Policy Responses. Innocenti Insight.

    ERIC Educational Resources Information Center

    United Nations Children's Fund, Florence (Italy). Innocenti Research Centre.

    This report examines policy responses and programming trends to combat the growing specter of child trafficking, focusing on the region of west and central Africa where strenuous advocacy efforts by UNICEF and its partners have helped to bring this problem to national and international attention. The report focuses on policy trends on child…

  12. Teaching in West Africa: Dig beneath the Surface

    ERIC Educational Resources Information Center

    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…

  13. Using Radio To Deliver Teacher Training in West Africa.

    ERIC Educational Resources Information Center

    Norman, Douglas

    Three radio stations serving the interior of Liberia, West Africa, were used to broadcast inservice training programs to teachers in grades 1-6. Most of the teachers had not attended college and had received only 5 weeks of preservice training before going into the classroom. Poor roads, a 6-month wet season, and lack of vehicles made face-to-face…

  14. Logical Demonomy Among the Ewe in West Africa

    ERIC Educational Resources Information Center

    Dzobo, N. K.

    1974-01-01

    Examines the indigenous pattern of moral behavior among the Ewe, an ethnic and linguistic group in West Africa, and assesses its role in moral education within the African context. The author develops a conceptual framework he calls "logical demonomy" that he uses to define the Ewe system of moral laws. (JT)

  15. Logical Demonomy Among the Ewe in West Africa

    ERIC Educational Resources Information Center

    Dzobo, N. K.

    1974-01-01

    Examines the indigenous pattern of moral behavior among the Ewe, an ethnic and linguistic group in West Africa, and assesses its role in moral education within the African context. The author develops a conceptual framework he calls "logical demonomy" that he uses to define the Ewe system of moral laws. (JT)

  16. Teaching in West Africa: Dig beneath the Surface

    ERIC Educational Resources Information Center

    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…

  17. Child Trafficking in West Africa: Policy Responses. Innocenti Insight.

    ERIC Educational Resources Information Center

    United Nations Children's Fund, Florence (Italy). Innocenti Research Centre.

    This report examines policy responses and programming trends to combat the growing specter of child trafficking, focusing on the region of west and central Africa where strenuous advocacy efforts by UNICEF and its partners have helped to bring this problem to national and international attention. The report focuses on policy trends on child…

  18. Measles Cases during Ebola Outbreak, West Africa, 2013–2106

    PubMed Central

    Colavita, Francesca; Biava, Mirella; Castilletti, Concetta; Quartu, Serena; Vairo, Francesco; Caglioti, Claudia; Agrati, Chiara; Lalle, Eleonora; Bordi, Licia; Lanini, Simone; Guanti, Michela Delli; Miccio, Rossella; Ippolito, Giuseppe; Capobianchi, Maria R.

    2017-01-01

    The recent Ebola outbreak in West Africa caused breakdowns in public health systems, which might have caused outbreaks of vaccine-preventable diseases. We tested 80 patients admitted to an Ebola treatment center in Freetown, Sierra Leone, for measles. These patients were negative for Ebola virus. Measles virus IgM was detected in 13 (16%) of the patients. PMID:28518027

  19. Sanaga Sud field - Offshore Cameroon, west Africa

    SciTech Connect

    Pauken, R.J. )

    1990-09-01

    The Sanaga Sud field, offshore Cameroon, is located just northwest of the coastal town of Kribi in the northern part of the Douala basin. The discovery well, Sanaga Sud A-1, was drilled in 1979 to test an apparent horst block that contained a prominent horizontal seismic amplitude. The Douala basin is one of a series of passive margin basins located along the coastline of central and southern Africa, and formed during the rifting of Africa and South America during the Early Cretaceous. Drilling results showed that the amplitude was a gas/water contact. Two appraisal wells, SSA-2 and SSA-3, were drilled in 1981. All three wells tested gas and condensate. Total recoverable hydrocarbons for the field are estimated to be approximately 1 tcf of gas. The trap in this field is composed of tilted and rotated fault blocks composed of interbedded Aptian to Albian sandstones, siltstones, and shales. The fault blocks were truncated by erosion (breakup unconformity) and later buried by a considerable thickness of onlapping Upper Cretaceous and Tertiary shale. The late Albian erosional unconformity forms the top of the trap over most of the field. Geochemical studies indicate a Lower Cretaceous source for the hydrocarbons. The gross pay thickness averages 250 m with an average porosity of 23% and an average permeability of 142 md. Reservoir lithologies range from well-sorted, massive sandstones to poorly sorted fine sandstones and siltstones containing shaly laminations that are carbonaceous and micaceous. The field is located predominantly in Block PH-38, but part of the field is in the Londji concession. Mobil Producing Cameroon, Inc., is the operator of PH-38 and Total Exploration and Production Cameroon is the operator of the Londji concession.

  20. West Africa land use land cover time series

    USGS Publications Warehouse

    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. Effects of the Boko Haram Insurgency Group in West and Central Africa

    DTIC Science & Technology

    2016-06-10

    THE EFFECTS OF THE BOKO HARAM INSURGENCY GROUP IN WEST AND CENTRAL AFRICA A thesis presented to the Faculty of the U.S...JUN 2016 4. TITLE AND SUBTITLE The Effects of the Boko Haram Insurgency Group in West and Central Africa 5a. CONTRACT NUMBER 5b. GRANT...Haram, Nigeria, Niger, Chad, Cameroon, West Africa, Central Africa, Insurgency, Phase Zero, Government, Social, Economic, Military 16. SECURITY

  2. Recent expansion of dengue virus serotype 3 in West Africa.

    PubMed

    Franco, L; Di Caro, A; Carletti, F; Vapalahti, O; Renaudat, C; Zeller, H; Tenorio, A

    2010-02-18

    Due to non-existing or limited surveillance in Africa, little is known about the epidemiology of dengue illness in the continent. Serological and virological data obtained from returning European travellers is a key complement to this often flawed information. In the past years, dengue 3 virus has emerged in West Africa and has been detected in travellers returning to Europe. The first dengue epidemic in Cape Verde with more than 17,000 cases from September to December 2009 demonstrated that dengue virus is still expanding worldwide to new territories.

  3. New vectors of Rift Valley fever in West Africa.

    PubMed Central

    Fontenille, D.; Traore-Lamizana, M.; Diallo, M.; Thonnon, J.; Digoutte, J. P.; Zeller, H. G.

    1998-01-01

    After an outbreak of Rift Valley fever in Southern Mauritania in 1987, entomologic studies were conducted in a bordering region in Sénégal from 1991 to 1996 to identify the sylvatic vectors of Rift Valley fever virus. The virus was isolated from the floodwater mosquitoes Aedes vexans and Ae. ochraceus. In 1974 and 1983, the virus had been isolated from Ae. dalzieli. Although these vectors differ from the main vectors in East and South Africa, they use the same type of breeding sites and also feed on cattle and sheep. Although enzootic vectors have now been identified in West Africa, the factors causing outbreaks remain unclear. PMID:9621201

  4. New vectors of Rift Valley fever in West Africa.

    PubMed

    Fontenille, D; Traore-Lamizana, M; Diallo, M; Thonnon, J; Digoutte, J P; Zeller, H G

    1998-01-01

    After an outbreak of Rift Valley fever in Southern Mauritania in 1987, entomologic studies were conducted in a bordering region in Sénégal from 1991 to 1996 to identify the sylvatic vectors of Rift Valley fever virus. The virus was isolated from the floodwater mosquitoes Aedes vexans and Ae. ochraceus. In 1974 and 1983, the virus had been isolated from Ae. dalzieli. Although these vectors differ from the main vectors in East and South Africa, they use the same type of breeding sites and also feed on cattle and sheep. Although enzootic vectors have now been identified in West Africa, the factors causing outbreaks remain unclear.

  5. Energy Reform for West Africa in Climate Change Crisis Era

    NASA Astrophysics Data System (ADS)

    Nwokocha, C.; Kasei, R.

    2009-04-01

    UNFCCC reports indicate that those who are least responsible for climate change are also the most vulnerable to its projected impacts. In no place is this more evident than in Sub-Saharan Africa, where greenhouse gas (GHG) emissions are negligible from a global scale. In Africa, energy demands could be the major factor that may lead to the increase of its emissions in the very near future. Forests are being lost for domestic energy, Oil produced energy increases carbon foot prints and Hydropower is unreliable due to uncertainties in rainfall patterns. By 2004, the energy consumption mix of West Africa was dominated by oil (58%) followed by natural gas (38%) and hydroelectric (8%) with coal and other energy forms not part of the mix. (Energy Information Administration, 2007). Rainfall and Global radiation using the Armstrong method was analyzed for sites in Nigeria and Ghana. A cost-benefit of the energy productions is presented.

  6. Implementing haemophilia care in Senegal, West Africa.

    PubMed

    Diop, S; Seck, M; Sy-Bah, D; Faye, B F; Sow-Ndoye, A; Gueye, Y B; Senghor, A B; Sall-Fall, A; Toure-Fall, A O; Dièye, T N; Thiam, D; Diakhate, L

    2014-01-01

    Despite significant progres on haemophilia care in developed world, this disease remains unknown in many sub-Saharan African countries. The objectives of this article were to report Senegalese experience on the management of haemophilia care through 18 years of follow-up. This cohort study included 140 patients (127 haemophilia A, 13 haemophilia B), followed in Dakar's haemophilia treatment centre from 1995 to 2012. Our study reported a prevalence of 2.3/100,000 male births, accounting for 11.6% of what is expected in Senegal. From the period 1995-2003 to 2004-2012, significant progress was seen including 67.9% increase in new patient's identification, 11.3 years reduction in mean age at diagnosis (from 15.5 to 4.2 years), lower mortality rate (from 15.3% to 6.8%) and age at death evolved from 6.5 to 23.3 years. Of the 50 haemophilia A patients who were tested for inhibitor presence, 10 were positive (eight severe and two moderate) that is prevalence of 20%. All patients were low responders since inhibitor titre was between 1.5 and 3.8 BU. Disabilities were seen in 36.5% of patients above 20 years old who had musculoskeletal sequels and 39% had no scholar or professional activities in our setting. Implementing haemophilia care in sub-Saharan Africa is a great challenge as this disease is not yet counted in national health problems in many countries. Lessons learned from this study show a significant improvement in diagnosis and prognosis parameters. This emphasizes the needs to set up such follow-up initiatives and to enhance medical and lay cooperation for better results.

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

    NASA Astrophysics Data System (ADS)

    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.

  8. The DACCIWA 2016 radiosonde campaign in southern West Africa

    NASA Astrophysics Data System (ADS)

    Fink, Andreas H.; Maranan, Marlon; Knippertz, Peter; Ngamini, Jean-Blaise; Francis, Sabastine

    2017-04-01

    Operational upper-air stations are very sparsely distributed over West Africa, resulting in the necessity to enhance radiosonde observations for the DACCIWA (Dynamics-Aerosol-Chemistry-Cloud Interactions in West Africa) experimental period during June-July 2016. Building on the AMMA (African Monsoon - Multidisciplinary Analyses) experience, existing infrastructures, as well as human networks, the upper air network was successfully augmented to a spatial density that is unprecedented for southern West Africa. Altogether, more than 750 experimental radiosondes were launched at seven stations in three countries along the Guinea Coast. From its outset, the DACCIWA radiosonde campaign had three pillars: (a) enhancing soundings at operational or quiescent AMMA radiosonde stations; (b) launching sondes at DACCIWA supersites and two additional DACCIWA field sites; and (c) collecting standard and - if possible - high-resolution data from other operational RS stations. In terms of (a), it was found during preparing recce visits to West Africa, that the AMMA-activated stations of Cotonou (Benin) and Abuja (Nigeria) were operational though almost "invisible" on the World Meteorological Organisation's Global Teleconnection System (GTS). These and other AMMA legacies facilitated the implementation of enhanced, four-times daily soundings at Abidjan (Ivory Coast), Cotonou and Parakou (both Benin). Two well-instrumented DACCIWA ground sites at Kumasi (Ghana) and Savé (Benin) performed 06 UTC soundings, being enhanced to four-times daily ascents during fifteen Intensive Observing Periods (IOPs). In addition, research staff and students from the Karlsruhe Institute of Technology (KIT) and African partners conducted up to five-times daily soundings at Lamto (Ivory Coast) and Accra (Ghana). Almost all of the experimental DACCIWA ascents were submitted to the GTS in real time and assimilated at least at three European numerical weather prediction centres that helped to improve their

  9. Vectorborne diseases in West Africa: geographic distribution and geospatial characteristics.

    PubMed

    Ratmanov, Pavel; Mediannikov, Oleg; Raoult, Didier

    2013-05-01

    This paper provides an overview of the methods in which geographic information systems (GIS) and remote sensing (RS) technology have been used to visualise and analyse data related to vectorborne diseases (VBD) in West Africa and to discuss the potential for these approaches to be routinely included in future studies of VBDs. GIS/RS studies of diseases that are associated with a specific geographic landscape were reviewed, including malaria, human African trypanosomiasis, leishmaniasis, lymphatic filariasis, Loa loa filariasis, onchocerciasis, Rift Valley fever, dengue, yellow fever, borreliosis, rickettsioses, Buruli ulcer and Q fever. RS data and powerful spatial modelling methods improve our understanding of how environmental factors affect the vectors and transmission of VBDs. There is great potential for the use of GIS/RS technologies in the surveillance, prevention and control of vectorborne and other infectious diseases in West Africa.

  10. Serosurveillance of Viral Pathogens Circulating in West Africa

    DTIC Science & Technology

    2016-05-20

    33 Keywords: serosurveillance; West Africa; Sierra Leone; Kenema; Lassa; Ebola ; Marburg; Rift 34 Valley fever; Crimean-Congo; alphavirus... Ebola , Marburg, Rift Valley fever, and Crimean-Congo hemorrhagic fever viruses as well as pan-50 assays for flaviviruses and alphaviruses. This assay...50.2% were positive for Lassa virus, 5.2% for Ebola virus, 10.7% for 54 Marburg virus, 1.8% for Rift Valley fever virus, 2.0% for Crimean-Congo

  11. Intense convection over West Africa during AMMA SOP3 experiment

    NASA Astrophysics Data System (ADS)

    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.

  12. Underdevelopment: Major Cause of Insecurity in West Africa

    DTIC Science & Technology

    2005-03-03

    dependent on such positive agricultural policies which aim at eradicating hunger and food insecurity , the presence of which may cause instability within...which could result in food insecurity and thus conflict. As already mentioned, countries in West Africa mainly export primary products which generally...deforestation. Deforestation also makes agricultural production unsustainable which affects both 13 food and cash crop production. Food insecurity brings

  13. Dynamics of Wet and Dry Years in West Africa.

    NASA Astrophysics Data System (ADS)

    Eltahir, Elfatih A. B.; Gong, Cuiling

    1996-05-01

    This paper proposes a theoretical framework for describing interannual climatic variability over West Africa. The dynamical theory of zonally symmetrical thermally direct circulations suggests that a meridional monsoon circulation must develop over any tropical region (off the equator) when the absolute vorticity near the tropopause reaches a threshold value of zero. However, for a moist atmosphere that satisfies a quasi-equilibrium balance between moist convection and the radiative forcing, the absolute vorticity at upper-tropospheric levels is a function of both latitude and the meridional distribution of boundary-layer entropy. Hence, the onset of a monsoon circulation depends in a nonlinear fashion on these two factors. The theory predicts that a flat distribution of entropy does not drive any circulation and that a relatively large gradient of entropy should drive a strong monsoon circulation. The location of the region of West Africa, relatively close to the equator, dictates that the dynamics of a monsoon over that region are relatively sensitive to interannual fluctuations in the meridional gradient of boundary-layer entropy. Here, we present observations on entropy and wind over West Africa during the monsoon seasons of 1958 and 1960. The following observations were consistent with the proposed relationship between boundary-layer entropy and the monsoon circulation: a large meridional gradient of boundary-layer entropy, a healthy monsoon, and wet conditions over the Sahel region were observed in 1958; and a nearly flat distribution of entropy, very weak circulation, and relatively dry conditions were observed in 1960. Moreover, the proposed theoretical relationship between the meridional gradient of boundary-layer entropy and the monsoon circulation over West Africa is consistent with the empirical observations of sea surface temperature anomalies (SSTAs) in the tropical Atlantic and rainfall in the Sahel region. Theoretically, a cold (warm) SSTA in the

  14. 77 FR 74265 - In the Matter of the Designation of Movement for Unity and Jihad in West Africa; Also Known as...

    Federal Register 2010, 2011, 2012, 2013, 2014

    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... Movement for Unity and Jihad in West Africa, also known as Movement ] for Oneness and Jihad in West Africa...

  15. Quaternary forest associations in lowland tropical West Africa

    NASA Astrophysics Data System (ADS)

    Miller, Charlotte S.; Gosling, William D.

    2014-01-01

    Terrestrial fossil pollen records are frequently used to reveal the response of vegetation to changes in both regional and global climate. Here we present a fossil pollen record from sediment cores extracted from Lake Bosumtwi (West Africa). This record covers the last c. 520 thousand years (ka) and represents the longest terrestrial pollen record from Africa published to date. The fossil pollen assemblages reveal dynamic vegetation change which can be broadly characterized as indicative of shifts between savannah and forest. Savannah formations are heavily dominated by grass (Poaceae) pollen (>55%) typically associated with Cyperaceae, Chenopodiaceae-Amaranthaceae and Caryophyllaceae. Forest formations are palynologically more diverse than the savannah, with the key taxa occurring in multiple forest zones being Moraceae, Celtis, Uapaca, Macaranga and Trema. The fossil pollen data indicate that over the last c. 520 ka the vegetation of lowland tropical West Africa has mainly been savannah; however six periods of forest expansion are evident which most likely correspond to global interglacial periods. A comparison of the forest assemblage composition within each interglacial suggests that the Holocene (11-0 ka) forest occurred under the wettest climate, while the forest which occurred at the time of Marine Isotope Stage 7 probably occurred under the driest climate.

  16. An oceanography summer school in Ghana, West Africa

    NASA Astrophysics Data System (ADS)

    Arbic, B. K.; Ansong, J. K.; Johnson, W.; Nyadjro, E. S.; Nyarko, E.

    2016-02-01

    Because oceanography is a global science, it clearly benefits from the existence of a world-wide network of oceanographers. As with most STEM disciplines, sub-Saharan Africa is not as well represented in the field of oceanography as it should be, given its large population. The need for oceanographers in sub-Saharan Africa is great, due to a long list of ocean-related issues affecting African development, including but not limited to fishing, oil drilling, sea level rise, coastal erosion, shipping, and piracy. We view this as an opportunity as well as a challenge. Many of the world's fastest growing economies are in sub-Saharan Africa, and STEM capacity building could further fuel this growth. With support from the US National Science Foundation, we ran an oceanography summer school from August 24-27, 2015, at the Regional Maritime University (RMU) in Ghana, West Africa. This first summer school was lecture-based, with a focus on basic chemical oceanography, basic physical oceanography, ocean modeling, and satellite oceanography. About 35 participants came to almost every lecture, and about 20 other participants came to some of the lectures as their time permitted. The participants included RMU faculty, 12 students from the Kwame Nkrumah University of Science and Technology, one Associate Oceanographer from the University of Ghana, and some participants from private sector companies and Ghanaian governmental agencies. There were long and lively discussions at the end of each lecture, and there was a lengthy discussion at the conclusion of the school on how to improve future summer schools. In 2016 and 2017, we plan to divide into smaller groups so that participants can pursue their particular interests in greater depth, and to allow time for student presentations. We also plan to begin exploring the potential for research partnerships, and to utilize distance learning to involve more faculty and students from locations throughout Ghana and perhaps from even other

  17. Laboratory Response to Ebola - West Africa and United States.

    PubMed

    Sealy, Tara K; Erickson, Bobbie R; Taboy, Céline H; Ströher, Ute; Towner, Jonathan S; Andrews, Sharon E; Rose, Laura E; Weirich, Elizabeth; Lowe, Luis; Klena, John D; Spiropoulou, Christina F; Rayfield, Mark A; Bird, Brian H

    2016-07-08

    The 2014-2016 Ebola virus disease (Ebola) epidemic in West Africa highlighted the need to maintain organized laboratory systems or networks that can be effectively reorganized to implement new diagnostic strategies and laboratory services in response to large-scale events. Although previous Ebola outbreaks enabled establishment of critical laboratory practice safeguards and diagnostic procedures, this Ebola outbreak in West Africa highlighted the need for planning and preparedness activities that are better adapted to emerging pathogens or to pathogens that have attracted little commercial interest. The crisis underscored the need for better mechanisms to streamline development and evaluation of new diagnostic assays, transfer of material and specimens between countries and organizations, and improved processes for rapidly deploying health workers with specific laboratory expertise. The challenges and events of the outbreak forced laboratorians to examine not only the comprehensive capacities of existing national laboratory systems to recognize and respond to events, but also their sustainability over time and the mechanisms that need to be pre-established to ensure effective response. Critical to this assessment was the recognition of how response activities (i.e., infrastructure support, logistics, and workforce supplementation) can be used or repurposed to support the strengthening of national laboratory systems during the postevent transition to capacity building and recovery. This report compares CDC's domestic and international laboratory response engagements and lessons learned that can improve future responses in support of the International Health Regulations and Global Health Security Agenda initiatives.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).

  18. Ebola virus disease outbreak - West Africa, September 2014.

    PubMed

    2014-10-03

    CDC is assisting ministries of health and working with other organizations to control and end the ongoing outbreak of Ebola virus disease (Ebola) in West Africa. The updated data in this report were compiled from ministry of health situation reports and World Health Organization (WHO) sources. Total case counts include all suspected, probable, and confirmed cases as defined by each country. These data reflect reported cases, which make up an unknown proportion of all actual cases. The data also reflect reporting delays that might vary from country to country.

  19. Update: Ebola virus disease outbreak--West Africa, October 2014.

    PubMed

    2014-10-31

    CDC is assisting ministries of health and working with other organizations to control and end the ongoing outbreak of Ebola virus disease (Ebola) in West Africa. The updated data in this report were compiled from situation reports from the Guinea Interministerial Committee for Response Against the Ebola Virus and the World Health Organization, the Liberia Ministry of Health and Social Welfare, and the Sierra Leone Ministry of Health and Sanitation. Total case counts include all suspected, probable, and confirmed cases as defined by each country. These data reflect reported cases, which make up an unknown proportion of all actual cases and reporting delays that vary from country to country.

  20. Climatology of radar anomalous propagation over West Africa

    NASA Astrophysics Data System (ADS)

    Kaissassou, Samuel; Lenouo, André; Tchawoua, Clément; Lopez, Philippe; Gaye, Amadou Thierno

    2015-02-01

    A comprehensive examination of 5 years of European Centre for Medium-Range Weather Forecasts (ECMWF) data from T511 L60 version of the ECMWF model to determine ducting conditions over West Africa and the computation of statistical distributions of the vertical gradient of refractivity determined from 2 years of radiosonde data over Dakar (14.41°N, 17.26°W), Douala (4°N, 9.7°E) and Niamey (13.35°N, 2.03°E) were carried out. It is found that diurnal and seasonal variations of the refractivity of the atmosphere are influenced by air temperature and water vapor pressure fluctuation. Refractivity gradients lower than -157 km-1 often results in spurious returned echoes and misinterpretation of radar images such as erroneous precipitation detection. The results obtained show that the local climate has an appreciable influence on the vertical profile of refractivity, especially the seasonal north-south movement of the Inter Tropical Discontinuity which is associated with the alternance of wet and dry seasons over the region. It is found that most of ducts occur in the night, morning (0000, 0600 UTC) and late afternoon (1800 UTC). The occurrence probability of abnormal propagation events, such as ducts, can provide some valuable information about the propagation of electromagnetic waves over West Africa.

  1. Economics of malaria prevention in US travelers to West Africa.

    PubMed

    Adachi, Kenji; Coleman, Margaret S; Khan, Nomana; Jentes, Emily S; Arguin, Paul; Rao, Sowmya R; LaRocque, Regina C; Sotir, Mark J; Brunette, Gary; Ryan, Edward T; Meltzer, Martin I

    2014-01-01

    Pretravel health consultations help international travelers manage travel-related illness risks through education, vaccination, and medication. This study evaluated costs and benefits of that portion of the health consultation associated with malaria prevention provided to US travelers bound for West Africa. The estimated change in disease risk and associated costs and benefits resulting from traveler adherence to malaria chemoprophylaxis were calculated from 2 perspectives: the healthcare payer's and the traveler's. We used data from the Global TravEpiNet network of US travel clinics that collect de-identified pretravel data for international travelers. Disease risk and chemoprophylaxis effectiveness were estimated from published medical reports. Direct medical costs were obtained from the Nationwide Inpatient Sample and published literature. We analyzed 1029 records from January 2009 to January 2011. Assuming full adherence to chemoprophylaxis regimens, consultations saved healthcare payers a per-traveler average of $14 (9-day trip) to $372 (30-day trip). For travelers, consultations resulted in a range of net cost of $20 (9-day trip) to a net savings of $32 (30-day trip). Differences were mostly driven by risk of malaria in the destination country. Our model suggests that healthcare payers save money for short- and longer-term trips, and that travelers save money for longer trips when travelers adhere to malaria recommendations and prophylactic regimens in West Africa. This is a potential incentive to healthcare payers to offer consistent pretravel preventive care to travelers. This financial benefit complements the medical benefit of reducing the risk of malaria.

  2. Testing Modeling Assumptions in the West Africa Ebola Outbreak

    NASA Astrophysics Data System (ADS)

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

    2016-10-01

    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.

  3. Testing Modeling Assumptions in the West Africa Ebola Outbreak

    PubMed Central

    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

  4. Trends and Issues in Vocational Technical Education in Francophone West Africa.

    ERIC Educational Resources Information Center

    Kogoe, Akrima

    Francophone West Africa has committed itself to the goal of universal formal education as the most effective method of insuring rapid economic and national development. (Francophone West Africa is composed of Senegal, Mauritania, Guinea, Mali, Ivory Coast, Togo, Benin, Niger, and Burkina-Faso.) The costly investments of limited fiscal resources in…

  5. The Legacy of Christianity in West Africa, with Special Reference to Burkina Faso

    ERIC Educational Resources Information Center

    Ouedraogo, Philippe

    2010-01-01

    In the following paper, I am going to discuss education and religion and consider the legacy of Christianity in education in West Africa with particular reference to the Evangelical churches in Burkina Faso. The paper will start with a general introduction to West Africa and the place of missionaries' activities in the region. I will then attempt…

  6. Trends and Issues in Vocational Technical Education in Francophone West Africa.

    ERIC Educational Resources Information Center

    Kogoe, Akrima

    Francophone West Africa has committed itself to the goal of universal formal education as the most effective method of insuring rapid economic and national development. (Francophone West Africa is composed of Senegal, Mauritania, Guinea, Mali, Ivory Coast, Togo, Benin, Niger, and Burkina-Faso.) The costly investments of limited fiscal resources in…

  7. Library Literature in English-Speaking West Africa; Its Achievements, Problems and Prospects.

    ERIC Educational Resources Information Center

    Nyarko, K.

    This report surveys the development of librarianship in West Africa since 1954, focusing primarily on the production of professional library literature in Gambia, Ghana, Nigeria, Sierra Leone, and Liberia, the five countries which constitute the sub-region of English-speaking West Africa. An overview of library developments is presented, and three…

  8. Climate Drives the Meningitis Epidemics Onset in West Africa

    PubMed Central

    Sultan, Benjamin; Labadi, Karima; Guégan, Jean-François; Janicot, Serge

    2005-01-01

    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. PMID:15696216

  9. The statistical distribution of aerosol properties in sourthern West Africa

    NASA Astrophysics Data System (ADS)

    Haslett, Sophie; Taylor, Jonathan; Flynn, Michael; Bower, Keith; Dorsey, James; Crawford, Ian; Brito, Joel; Denjean, Cyrielle; Bourrianne, Thierry; Burnet, Frederic; Batenburg, Anneke; Schulz, Christiane; Schneider, Johannes; Borrmann, Stephan; Sauer, Daniel; Duplissy, Jonathan; Lee, James; Vaughan, Adam; Coe, Hugh

    2017-04-01

    The population and economy in southern West Africa have been growing at an exceptional rate in recent years and this trend is expected to continue, with the population projected to more than double to 800 million by 2050. This will result in a dramatic increase in anthropogenic pollutants, already estimated to have tripled between 1950 and 2000 (Lamarque et al., 2010). It is known that aerosols can modify the radiative properties of clouds. As such, the entrainment of anthropogenic aerosol into the large banks of clouds forming during the onset of the West African Monsoon could have a substantial impact on the region's response to climate change. Such projections, however, are greatly limited by the scarcity of observations in this part of the world. As part of the Dynamics-Aerosol-Chemistry-Cloud Interactions in West Africa (DACCIWA) project, three research aircraft were deployed, each carrying equipment capable of measuring aerosol properties in-situ. Instrumentation included Aerosol Mass Spectrometers (AMS), Single Particle Soot Photometers (SP2), Condensation Particle Counters (CPC) and Scanning Mobility Particle Sizers (SMPS). Throughout the intensive aircraft campaign, 155 hours of scientific flights covered an area including large parts of Benin, Togo, Ghana and parts of Côte D'Ivoire. Approximately 70 hours were dedicated to the measurement of cloud-aerosol interactions, with many other flights producing data contributing towards this objective. Using datasets collected during this campaign period, it is possible to build a robust statistical understanding of aerosol properties in this region for the first time, including size distributions and optical and chemical properties. Here, we describe preliminary results from aerosol measurements on board the three aircraft. These have been used to describe aerosol properties throughout the region and time period encompassed by the DACCIWA aircraft campaign. Such statistics will be invaluable for improving future

  10. Characteristics of mid-level clouds over West Africa

    NASA Astrophysics Data System (ADS)

    Bourgeois, Elsa; Bouniol, Dominique; Couvreux, Fleur; Guichard, Françoise; Marsham, John; Garcia-Carreras, Luis; Birch, Cathryn; Parker, Doug

    2017-04-01

    Clouds have a major impact on the distribution of water and energy fluxes within the atmosphere. They also represent one of the main sources of uncertainties in global climate models as a result of the difficulty to parametrize cloud processes. However, in West Africa, the cloud type, occurrence and radiative effects have not been extensively documented. This region is characterized by a strong seasonality with precipitation occurring in the Sahel from June to September (monsoon season). This period also coincides with the annual maximum of the cloud cover. Taking advantage of the one-year ARM Mobile Facility (AMF) deployment in 2006 in Niamey (Niger), Bouniol et al (2012) documented the distinct cloud types and showed the frequent occurrence of mid-level clouds (around 6 km height) and their substantial impact on the surface short-wave and long-wave radiative fluxes. Furthermore, in a process-oriented evaluation of climate models, Roehrig et al (2013) showed that these mid-level clouds are poorly represented in numerical models. The aim of this work is to document the macro- and microphysical properties of mid-level clouds and the environment in which such clouds occur across West Africa. To document those clouds, we extensively make use of observations from lidar and cloud radar either deployed at ground-based sites (Niamey and Bordj Badji Mokhtar (Sahara)) or on-board the A-Train constellation (CloudSat/CALIPSO). These datasets reveal the temporal and spatial occurrence of those clouds. They are found throughout the year with a predominance around the monsoon season and are preferentially observed in the Southern and Western part of West Africa which could be linked to the dynamics of the Saharan heat low. Those clouds are usually quite thin (most of them are less than 1000m deep). A clustering method applied to this data allows us to identify three different types of clouds : one with low bases, one with high bases and another with large thicknesses. The first

  11. Acute Arboviral Infections in Guinea, West Africa, 2006

    PubMed Central

    Jentes, Emily S.; Robinson, Jaimie; Johnson, Barbara W.; Conde, Ibrahima; Sakouvougui, Yosse; Iverson, Jennifer; Beecher, Shanna; Bah, M. Alpha; Diakite, Fousseny; Coulibaly, Mamadi; Bausch, Daniel G.

    2010-01-01

    Acute febrile illnesses comprise the majority of the human disease burden in sub-Saharan Africa. We hypothesized that arboviruses comprised a considerable proportion of undiagnosed febrile illnesses in Guinea and sought to determine the frequency of arboviral disease in two hospitals there. Using a standard case definition, 47 suspected cases were detected in approximately 4 months. Immunoglobulin M antibody capture enzyme-linked immunosorbent assays and plaque-reduction neutralization assays revealed that 63% (30/47) of patients were infected with arboviruses, including 11 West Nile, 2 yellow fever, 1 dengue, 8 chikungunya, and 5 Tahyna infections. Except for yellow fever, these are the first reported cases of human disease from these viruses in Guinea and the first reported cases of symptomatic Tahyna infection in Africa. These results strongly suggest that arboviruses circulate and are common causes of disease in Guinea. Improving surveillance and laboratory capacity for arbovirus diagnoses will be integral to understanding the burden posed by these agents in the region. PMID:20682888

  12. How many rifts are there in West Africa?

    NASA Astrophysics Data System (ADS)

    Freeth, S. J.

    1984-02-01

    The West African Rift System has, for the last ten years, been thought to consist of five interconnected rifts extending from the Gulf of Guinea deep into the heart of Africa. Careful re-examination of the geophysical evidence makes it quite clear that there are only three interconnected rifts in West Africa; the Lower Benue Rift which extends to the northeast from the Gulf of Guinea to a triple junction near Chum, and the Gongola and Yola Rifts which extend to the north and east, respectively, from the Chum triple junction. These three rifts opened during the earlier part of the Mesozoic and were subsequently filled with Cretaceous sediments. The evidence for two further rifts, the Ati Rift and the Fort Archambault Rift which were thought to extend to the northeast and southeast, respectively, from a triple junction at the eastern end of the Yola Rift, does not stand up to re-examination. The "Ati Rift" was thought to follow a major linear positive gravity anomaly which had been mapped beneath the Quaternary sediments of the Chad Basin. The main gravity anomaly is separated from the Yola Rift by over 300 km and is probably due to a linear body of basic volcanic or volcano-clastic rocks associated with a suture of Pan-African age. Within the gap, between the main anomaly and the Yola Rift, there are three localised positive anomalies which relate to a gabbro of Precambrian age, a band of dense meta-sediments within the Basement Complex and an acid igneous complex of Palaeogene age. The anomaly as a whole is therefore a sequence of unrelated anomalies, none of which are due to features of Mesozoic age. The "Fort Archambault Rift" was thought to follow a major linear negative gravity anomaly which has been mapped beneath the Quaternary sediments of the Chad Basin. To a large extent the negative anomaly overlies the fosse de Baké-Birao (Baké-Birao Basin) which is itself part of a far larger structure that extends, parallel to the southern margin of the West African

  13. A case of Plasmodium ovale malaria imported from West Africa.

    PubMed

    Kang, Yunjung; Yang, Jinyoung

    2013-04-01

    Malaria is a parasitic infection caused by Plasmodium species. Most of the imported malaria in Korea are due to Plasmodium vivax and Plasmodium falciparum, and Plasmodium ovale infections are very rare. Here, we report a case of a 24-year-old American woman who acquired P. ovale while staying in Ghana, West Africa for 5 months in 2010. The patient was diagnosed with P. ovale malaria based on a Wright-Giemsa stained peripheral blood smear, Plasmodium genus-specific real-time PCR, Plasmodium species-specific nested PCR, and sequencing targeting 18S rRNA gene. The strain identified had a very long incubation period of 19-24 months. Blood donors who have malaria with a very long incubation period could be a potential danger for propagating malaria. Therefore, we should identify imported P. ovale infections not only by morphological findings but also by molecular methods for preventing propagation and appropriate treatment.

  14. The 1986 lake nyos gas disaster in cameroon, west Africa.

    PubMed

    Kling, G W; Clark, M A; Wagner, G N; Compton, H R; Humphrey, A M; Devine, J D; Evans, W C; Lockwood, J P; Tuttle, M L; Koenigsberg, E J

    1987-04-10

    The sudden, catastrophic release of gas from Lake Nyos on 21 August 1986 caused the deaths of at least 1700 people in the northwest area of Cameroon, West Africa. Chemical, isotopic, geologic, and medical evidence support the hypotheses that (i) the bulk of gas released was carbon dioxide that had been stored in the lake's hypolimnion, (ii) the victims exposed to the gas cloud died of carbon dioxide asphyxiation, (iii) the carbon dioxide was derived from magmatic sources, and (iv) there was no significant, direct volcanic activity involved. The limnological nature of the gas release suggests that hazardous lakes may be identified and monitored and that the danger of future incidents can be reduced.

  15. Mathematical modeling of the West Africa Ebola epidemic

    PubMed Central

    Chretien, Jean-Paul; Riley, Steven; George, Dylan B

    2015-01-01

    As of November 2015, the Ebola virus disease (EVD) epidemic that began in West Africa in late 2013 is waning. The human toll includes more than 28,000 EVD cases and 11,000 deaths in Guinea, Liberia, and Sierra Leone, the most heavily-affected countries. We reviewed 66 mathematical modeling studies of the EVD epidemic published in the peer-reviewed literature to assess the key uncertainties models addressed, data used for modeling, public sharing of data and results, and model performance. Based on the review, we suggest steps to improve the use of modeling in future public health emergencies. DOI: http://dx.doi.org/10.7554/eLife.09186.001 PMID:26646185

  16. Socioeconomic consequences of blinding onchocerciasis in west Africa.

    PubMed Central

    Evans, T. G.

    1995-01-01

    Onchocerciasis or river blindness, a major cause of irreversible blindness among adults, has been the focus of international disease control efforts for over 20 years in West Africa. This paper employs the international classification of impairment, disability and handicap (ICIDH) to interpret results from a field study to assess the socioeconomic consequences of onchocerciasis in Guinea in 1987. In a sample of 136 blind, 94 visually impaired and 89 well-sighted persons, decreasing visual acuity is strongly associated with mobility, occupational and marital handicaps. Individual, household and disease correlates were explored. The implications of these findings for the ICIDH concept of handicap are discussed with particular emphasis on the need to extend analysis beyond the individual when assessing the socioeconomic consequences of disabling disease. PMID:7554022

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

    NASA Technical Reports Server (NTRS)

    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

  18. Economics of Malaria Prevention in US Travelers to West Africa

    PubMed Central

    Adachi, Kenji; Coleman, Margaret S.; Khan, Nomana; Jentes, Emily S.; Arguin, Paul; Rao, Sowmya R.; LaRocque, Regina C.; Sotir, Mark J.; Brunette, Gary; Ryan, Edward T.; Meltzer, Martin I.

    2014-01-01

    Background. Pretravel health consultations help international travelers manage travel-related illness risks through education, vaccination, and medication. This study evaluated costs and benefits of that portion of the health consultation associated with malaria prevention provided to US travelers bound for West Africa. Methods. The estimated change in disease risk and associated costs and benefits resulting from traveler adherence to malaria chemoprophylaxis were calculated from 2 perspectives: the healthcare payer's and the traveler's. We used data from the Global TravEpiNet network of US travel clinics that collect de-identified pretravel data for international travelers. Disease risk and chemoprophylaxis effectiveness were estimated from published medical reports. Direct medical costs were obtained from the Nationwide Inpatient Sample and published literature. Results. We analyzed 1029 records from January 2009 to January 2011. Assuming full adherence to chemoprophylaxis regimens, consultations saved healthcare payers a per-traveler average of $14 (9-day trip) to $372 (30-day trip). For travelers, consultations resulted in a range of net cost of $20 (9-day trip) to a net savings of $32 (30-day trip). Differences were mostly driven by risk of malaria in the destination country. Conclusions. Our model suggests that healthcare payers save money for short- and longer-term trips, and that travelers save money for longer trips when travelers adhere to malaria recommendations and prophylactic regimens in West Africa. This is a potential incentive to healthcare payers to offer consistent pretravel preventive care to travelers. This financial benefit complements the medical benefit of reducing the risk of malaria. PMID:24014735

  19. Drivers of Streamflow Variability in West and Central Africa

    NASA Astrophysics Data System (ADS)

    Dieppois, B.; Sidibe, M.; Lawler, D.; Mahe, G. M.; Paturel, J. E.

    2016-12-01

    The unprecedented droughts episodes that struck West Africa during 1970s and 1980s, have triggered a plethora of studies investigating rainfall variability and its impacts on food production systems. In general, studies exploring impacts of rainfall variability on streamflow were restrained to basin scale with few of them investigating impacts at the regional scale. This study aims at bridging the gap through an estimation of streamflow variability over West and Central Africa. First, streamflow time series retrieved from the HSM-SIEREM database are completed based on correlations between gauging stations. This is an important outcome of this study, which proposes to create a homogeneous streamflow database, for the first time, over this region. Runoff variability and trends in the region over the past decades are assessed using multi-temporal trend analysis on the filled time series between 1950 and 2010. Second, a wavelet-based approach is used to detect the dominant timescales of streamflow variability. The challenge is to separate human (e.g. land use) induced and climate induced variability in the changes of hydrological regimes. The detected trends are significant for most of the stations and highlight the fluctuations of rainfall during the past decades. The findings emphasize interannual to decadal variability and significant correlations between rainfall and streamflow for some of the regions implying the importance of climate variability on hydrological regimes. Regions where no significant correlations with climatic variables are found underline the impacts of anthropogenic activity mainly land use and water management practices on streamflow variability. Even though, relationships between rainfall and streamflow are very complex and difficult to capture, defining the issue on a regional scale provides hints to improve hydrological modelling practices.

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

    NASA Technical Reports Server (NTRS)

    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.

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

    ERIC Educational Resources Information Center

    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,…

  2. La Langue francaise en Afrique occidentale francophone (The French Language in West Africa).

    ERIC Educational Resources Information Center

    Kwofie, Emmanuel N.

    This is a reflection on certain aspects of sociolinguistic and linguistic problems of French in West Africa, particularly in Senegal and the Ivory Coast. The sociolinguistic section discusses the role French has played in Africa and still plays vis-a-vis African languages and English. Conditions in which French is used and attitudes both of…

  3. Modulation of precipitation over West Africa by equatorial waves

    NASA Astrophysics Data System (ADS)

    Schlüter, Andreas; van der Linden, Roderick; Vogel, Peter; Fink, Andreas H.; Knippertz, Peter

    2017-04-01

    Equatorial waves can couple with deep convection and thus modulate rainfall on the synoptic timescale throughout the tropics. Until now, however, no comparative study of the influence of all the different wave types on precipitation has been performed specifically for West Africa. To fill this gap, the following wave types were analyzed for the pre-/post- and full monsoon season (April to October): (1) the Madden-Julian Oscillation (MJO), (2) Kelvin waves, (3) equatorial Rossby waves, (4) eastward-propagating inertia gravity waves, (5) mixed Rossby-gravity waves and (6) tropical disturbances/African Easterly Waves. The different wave types were filtered in the wavenumber-frequency spectrum of outgoing longwave radiation. Eight different wave phases were defined from a phase diagram that can be calculated from the time-derivative of the filtered wave signal. Subsequently, composites of dynamical and thermodynamical fields for each wave phase of the different wave types were plotted using the ERA Interim reanalysis from the European Centre for Medium-Range Weather Forecasts. This way the propagation of the wave can be depicted. All aforementioned wave types, except the fast eastward-propagating inertia gravity wave, show consistent and significant influence on West African rainfall. The influence of the waves can be seen far into the subtropics for some wave types. The expected theoretical structure is confirmed by the analysis of upper- and lower-level divergence, wind and geopotential height. An interaction between the tropical and extratropical regime appears to occur for the MJO and equatorial Rossby waves. The mechanism involved in this interaction, however, is not fully understood. Composites of low-level wind shear, convective available potential energy and mid-level moisture are used to analyze whether waves create favorable conditions for the organization of convection. Additionally, the source regions of moisture were identified using moisture fields and

  4. The Onchocerciasis Control Programme in West Africa (OCP).

    PubMed

    Boatin, B

    2008-09-01

    The Onchocerciasis Control Programme in West Africa (OCP) started operations in 1975. Its main objectives were to eliminate human onchocerciasis, as a disease of public-health importance and an obstacle to socio-economic development, from the Programme area. By the end of 2002, the OCP covered 11 West African countries, and had introduced large-scale Mectizan (ivermectin) distribution to about 10 million people, through the communitydirected treatment approach, with treatment coverages ranging from 51%-81%. Research on large-scale Mectizan use illustrated the importance of evidence-based results, the power of multicountry studies, the need for social science in community-driven endeavours and operations research, and the value of empowering communities as allies in disease control. The generous donation of Mectizan by Merck & Co., Inc., has increased general interest in health-related public-private partnerships and generated the momentum for other donations to tackle other diseases. The vector control on which the OCP was initially based successfully interrupted the transmission of the parasite causing human onchocerciasis, Onchocerca volvulus, in many areas. The introduction of Mectizan led to the decline in anterior-segment lesions in the eye and the arrest of posterior-segment lesions. The drug continues to be highly effective in morbidity control, although recently there have been reports of sub-optimal responses in some adult O. volvulus, albeit in a few, very small and isolated foci.

  5. Cropland estimation in West Africa: Case of Mali

    NASA Astrophysics Data System (ADS)

    Samasse, K.; Hanan, N. P.

    2016-12-01

    Ensure food security is a global concern. Particularly for developing countries, like Mali in West Africa, where agriculture is mostly rainfed. This type of agriculture is very sensitive to climate variabilities. Making these developing countries more susceptible to droughts and leading sometimes to crop loss. In this context, an accurate estimation of cropland and crop yield is critical for food security policies. The aim of this research is to create an improved remote sensing-based land cover product for Mali with a specific focus on agriculture class. We used national agriculture statistics as reference dataset to estimate the accuracy of existing global land cover products (GLC2000 and MODIS Land Cover). Less than 30 % of producer accuracy is found for agriculture class in both GLC2000 and MODIS Land Cover for Mali, with a higher confusion between Savannah and Agriculture classes in the southern part. We developed two new land cover products for Mali. Firstly, we integrated the two Land Cover products pixel by pixel. We kept pixels having the same class and estimated the land cover type for pixels with different class names Google Earth. Secondly, we did a supervised classification of Landsat images using a new dataset as training data. This new dataset is a 2 by 2 kilometers data points derived from Landsat images, Google Earth and West African region experts' opinions. The second land cover product has a better accuracy (80%) for cropland class. Keywords: Cropland, Food security, Land cover, Mali

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

    PubMed Central

    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. PMID:25419290

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

    PubMed

    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.

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

    PubMed Central

    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

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

    PubMed

    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

    2016-09-01

    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. 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. 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. 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.

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

    NASA Astrophysics Data System (ADS)

    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.

  11. Sustainable Development of Research Capacity in West Africa

    NASA Astrophysics Data System (ADS)

    Liebe, J. R.; Rogmann, A.; Falk, U.; Nyarko, B. K.; Amisigo, B.; Barry, B.; Vlek, P. L.

    2010-12-01

    In West Africa, the management and efficient use of natural resources is becoming ever more important. This is largely due to steeply increasing demand through population growth and economic development, and through the effects of greater uncertainty due to climate and environmental change. Developing research capacity in these countries is an essential step in enabling them to assess their natural resources independently, and to develop national strategies and policies to manage their natural resources in the light of growing demand and increasing climatic uncertainty. The project “Sustainable Development of Research Capacity in West Africa based on the GLOWA Volta Project” (SDRC) is an 18 month project, funded by the German Ministry of Education and Research, to strengthen the research capacity in West Africa. The SDRC is based on three columns: I. knowledge transfer and strengthening of human capacity; II. strengthening of infrastructural research capacity; and III. strengthening the institutional capacity. The SDRC makes use of the wide range of research results and decision support tools developed in the GLOWA Volta Project (GVP), a nine-year, interdisciplinary research project (2000-2009) with a regional focus on the Volta Basin. The tools and models that have been transferred and trained in the framework of GVP and SDRC cover a range of topics, such as modeling the onset of the rainy season, hydrological, economic, hydro-economic modeling, GIS and Remote Sensing, and the training of database managers, to name a few. Infrastructural capacity is developed by the transfer of a micro-meteorological research network to the Meteorological Service of Burkina Faso, joint operation of a tele-transmitted hydrological gauging network with the Hydrological Service of Ghana, and the provision of hard- and software capacity to use the trained models. At the center of the SDRC effort is the strengthening of the Volta Basin Authority, a newly established river basin

  12. Effective elastic thickness and crustal thickness variations in west central Africa inferred from gravity data

    SciTech Connect

    Poudjom Djomani, Y.H.; Nnange, J.M.; Ebinger, C.J.

    1995-11-10

    This report uses coherence function analysis of 32,000 gravity and topography points from Cameroon west Africa to determine the relationship between the plate tectonic and flexural rigidity of the lithosphere in terms of the crusts effective elastic thickness.

  13. The Africanization of Syllabuses in Education in Anglophone and Francophone Countries of West Africa

    ERIC Educational Resources Information Center

    Kelly, Michael

    1971-01-01

    Comparison of syllabuses concludes that in West Africa English-speaking countries have made greater progress in Africanizing both the content and language of instruction than French-speaking countries. (RT)

  14. Water Sources in Cape Verde and West Africa. Water in Africa.

    ERIC Educational Resources Information Center

    Maher, Robert

    The Water in Africa Project was realized over a 2-year period by a team of Peace Corps volunteers, World Wise Schools (WWS) classroom teachers, and WWS staff members. As part of an expanded, detailed design, resources were collected from over 90 volunteers serving in African countries, photos and stories were prepared, and standards-based learning…

  15. Guidelines for Developing an Instructional Unit on Africa: The Manding of West Africa.

    ERIC Educational Resources Information Center

    Bay, Edna G.

    The paper provides guidelines to help secondary school social studies classroom teachers develop and implement a unit on the Manding ethnic group in Africa. The objective is to illustrate how the cultural approach to Manding and to area studies in general can help students understand economic and social structures in other nations. Manding is the…

  16. Guidelines for Developing an Instructional Unit on Africa: The Manding of West Africa.

    ERIC Educational Resources Information Center

    Bay, Edna G.

    The paper provides guidelines to help secondary school social studies classroom teachers develop and implement a unit on the Manding ethnic group in Africa. The objective is to illustrate how the cultural approach to Manding and to area studies in general can help students understand economic and social structures in other nations. Manding is the…

  17. A General Survey of Religious Concepts and Art of North, East, South, and West Africa.

    ERIC Educational Resources Information Center

    Stewart, Rohn

    This paper, a summary of a multi-carousel slide presentation, reviews literature on the cultures, religions, and art of African people. Before focusing on West Africa, highlights of the lifestyles, religions, and icons of non-maskmaking cultures of North, West and South African people are presented. Clarification of West African religious concepts…

  18. Back to Africa: Second Chances for the Children of West African Immigrants

    ERIC Educational Resources Information Center

    Bledsoe, Caroline H.; Sow, Papa

    2011-01-01

    This paper examines the phenomenon of West African parents living in Europe and North America who send their older children back home: from places of high immigrant aspiration to those of hardship and privation. Drawing on a project on West African immigration to Europe and on previous field studies in Africa, we conclude that West African…

  19. Back to Africa: Second Chances for the Children of West African Immigrants

    ERIC Educational Resources Information Center

    Bledsoe, Caroline H.; Sow, Papa

    2011-01-01

    This paper examines the phenomenon of West African parents living in Europe and North America who send their older children back home: from places of high immigrant aspiration to those of hardship and privation. Drawing on a project on West African immigration to Europe and on previous field studies in Africa, we conclude that West African…

  20. A re-evaluation of the origin of hepatitis C virus genotype 2 in West Africa.

    PubMed

    Purdy, Michael A; Forbi, Joseph C; Sue, Amanda; Layden, Jennifer E; Switzer, William M; Opare-Sem, Ohene K; Phillips, Richard O; Khudyakov, Yury E

    2015-08-01

    Hepatitis C virus (HCV) is classified into seven genotypes based on genetic diversity, and most genotypes have been found in Africa. Infections with HCV genotype 2 (HCV2) are most prevalent in West Africa and it was suggested that HCV2 originated in West Africa. To better understand the evolutionary epidemiology of HCV2 in Africa, we examined new NS5B sequences of HCV2 strains obtained from Côte d'Ivoire, Ghana and Nigeria sequenced at the Centers for Disease Control and Prevention with those available from West, North and Central Africa. Bayesian phylogeographic analysis using a discrete trait model showed that Ghana was the most likely geographical region for the origin of HCV2. Spread of HCV2 from Ghana did not appear to be through diffusion to adjacent countries along the coast. Rather, it was transmitted from Ghana to many distant countries in Africa, suggesting that certain routes of geographical dissemination were historically more efficient than mere proximity and that the HCV2 epidemic history in West Africa is extremely complex.

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

    NASA Astrophysics Data System (ADS)

    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.

  2. Epidemiological situation of Ebola virus disease in West Africa.

    PubMed

    Arima, Yuzo; Shimada, Tomoe

    2015-01-01

    After Guinea reported an outbreak of Ebola virus disease (EVD) in March 2014, EVD spread to neighboring Sierra Leone and Liberia in West Africa. Since then, the EVD outbreak spread over a wide geographic area among these three countries, and became the largest EVD epidemic ever with unprecedented numbers of confirmed cases and fatalities. As of April 2015, one year past the start of the outbreak, transmission is still ongoing. And, while six other countries, including those outside of the African continent (the United Kingdom, Spain, and the United States), have reported EVD cases, the source of the infection all originated from Guinea, Sierra Leone, or Liberia. As for the pathogen, Ebola virus, the route of transmission and associated prevention measures are well known, and change in the virulence or transmissibility of the virus has not been confirmed. However, there are specific factors that likely contributed to the unprecedented magnitude of the current EVD outbreak. In addition to the limited and poor medical and public health infrastructure in the affected countries, implementing appropriate responses rapidly was challenging for these countries, whose medical community, the general public, and governments had never experienced EVD before.

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

    PubMed Central

    Khaleque, Abdul; Sen, Parongama

    2017-01-01

    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) ∝ 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. PMID:28205617

  4. Quantifying Cloud Aerosol Interactions in Southern West Africa

    NASA Astrophysics Data System (ADS)

    Rosenberg, Phil; Marsham, John; Field, Paul; Hill, Adrian; Shipway, Ben; Wilkinson, Jonathan; Grosvenor, Daniel; Knippertz, Peter

    2017-04-01

    At the peak of the summer monsoon the area of heaviest rains lies to the north of southern West Africa. During this period, a stratus deck tends to form overnight in response to night time cooling and moisture fluxes from the south. With the onset of day-time solar heating this is transformed to stratocumulus and cumulus, sometimes forming deeper precipitating clouds. The DACCIWA project is investigating the meteorology and chemistry of this region including modelling and field studies. Here we present results using a new bulk multi-moment cloud-aerosol interaction scheme, known as CASIM, implemented within the Met Office Unified Model. This model allows prescribed aerosol fields to be used and we utilise this feature to investigate the sensitivity of properties of the stratocumulus to aerosol concentration. We are simulating a 3 day case study using convective permitting resolutions over a regional scale. For our case study we find that changing the aerosol concentration causes changes in the low cloud fraction and therefore affects top of atmosphere outgoing radiation. The relationship is nonlinear, however the largest aerosol concentrations provide the largest cloud cover. We discuss mechanisms for these changes and implications for modelling of the regional climate.

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

    PubMed

    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.

  6. The 2014 Ebola virus disease outbreak in West Africa.

    PubMed

    Gatherer, Derek

    2014-08-01

    On 23 March 2014, the World Health Organization issued its first communiqué on a new outbreak of Ebola virus disease (EVD), which began in December 2013 in Guinée Forestière (Forested Guinea), the eastern sector of the Republic of Guinea. Located on the Atlantic coast of West Africa, Guinea is the first country in this geographical region in which an outbreak of EVD has occurred, leaving aside the single case reported in Ivory Coast in 1994. Cases have now also been confirmed across Guinea as well as in the neighbouring Republic of Liberia. The appearance of cases in the Guinean capital, Conakry, and the transit of another case through the Liberian capital, Monrovia, presents the first large urban setting for EVD transmission. By 20 April 2014, 242 suspected cases had resulted in a total of 147 deaths in Guinea and Liberia. The causative agent has now been identified as an outlier strain of Zaire Ebola virus. The full geographical extent and degree of severity of the outbreak, its zoonotic origins and its possible spread to other continents are sure to be subjects of intensive discussion over the next months. © 2014 The Authors.

  7. Ebola viral disease outbreak--West Africa, 2014.

    PubMed

    Dixon, Meredith G; Schafer, Ilana J

    2014-06-27

    On March 21, 2014, the Guinea Ministry of Health reported the outbreak of an illness characterized by fever, severe diarrhea, vomiting, and a high case-fatality rate (59%) among 49 persons. Specimens from 15 of 20 persons tested at Institut Pasteur in Lyon, France, were positive for an Ebola virus by polymerase chain reaction. Viral sequencing identified Ebola virus (species Zaïre ebolavirus), one of five viruses in the genus Ebolavirus, as the cause. Cases of Ebola viral disease (EVD) were initially reported in three southeastern districts (Gueckedou, Macenta, and Kissidougou) of Guinea and in the capital city of Conakry. By March 30, cases had been reported in Foya district in neighboring Liberia (1), and in May, the first cases identified in Sierra Leone were reported. As of June 18, the outbreak was the largest EVD outbreak ever documented, with a combined total of 528 cases (including laboratory-confirmed, probable, and suspected cases) and 337 deaths (case-fatality rate = 64%) reported in the three countries. The largest previous outbreak occurred in Uganda during 2000-2001, when 425 cases were reported with 224 deaths (case-fatality rate = 53%). The current outbreak also represents the first outbreak of EVD in West Africa (a single case caused by Taï Forest virus was reported in Côte d'Ivoire in 1994 [3]) and marks the first time that Ebola virus transmission has been reported in a capital city.

  8. Spatial spread of the West Africa Ebola epidemic

    PubMed Central

    Pulliam, J. Tomlin; Alexander, Laura W.; Rohani, Pejman; Drake, John M.

    2016-01-01

    Controlling Ebola outbreaks and planning an effective response to future emerging diseases are enhanced by understanding the role of geography in transmission. Here we show how epidemic expansion may be predicted by evaluating the relative probability of alternative epidemic paths. We compared multiple candidate models to characterize the spatial network over which the 2013–2015 West Africa epidemic of Ebola virus spread and estimate the effects of geographical covariates on transmission during peak spread. The best model was a generalized gravity model where the probability of transmission between locations depended on distance, population density and international border closures between Guinea, Liberia and Sierra Leone and neighbouring countries. This model out-performed alternative models based on diffusive spread, the force of infection, mobility estimated from cell phone records and other hypothesized patterns of spread. These findings highlight the importance of integrated geography to epidemic expansion and may contribute to identifying both the most vulnerable unaffected areas and locations of maximum intervention value. PMID:27853607

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

    PubMed

    Khaleque, Abdul; Sen, Parongama

    2017-02-16

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

    PubMed Central

    Behrens, Ron H; Carroll, Bernadette; Smith, Valerie; Alexander, Neal

    2008-01-01

    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 < 0.0001. The risk for travellers from the UK visiting for other reasons declined 2.7 fold, at an annual decrease of 7.0%, with the incidence in West African visitors to the UK falling by 2.3 fold, a rate of 7.9% annually. 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. PMID:19000299

  11. The stratigraphy of the Taoudeni basin, west Africa

    SciTech Connect

    Ratcliffe, K.T.; Moody, R.T.J. )

    1993-09-01

    The Taoudeni basin is one of the major structural units of the west African craton, with an areal extent in excess of 2,000,000 km[sup 2]. Sediment thicknesses can reach over 3000 m, but have an average thickness of 1250 m. The majority of the basin-fill sediments are Precambrian to Carboniferous, with Mesozoic rocks present in the eastern margin adjacent to the Adrar des Iforas. Due to the paucity of exploration in the Taoudoni basin, there are no detailed works on source potential, maturity, or reservoir quality. However, within the sediment pile, there are excellent potential reservoirs, in the form of poorly cemented sandstones, and apparently organic-rich sediments, which may have source potential. Three major Paleozoic tectono-sedimentary units are recognized within the basin, all of which are found in the Adrar de Mauritania, which is taken as the [open quotes]type section[close quotes] for the Taoudeni basin. Unit 1 (Upper Riphean) is composed of alternating sandstones, limestones, and mudstones, which show rapid lateral thickness variations. Units 2 and 3 are far more uniform in thickness and distribution. Unit 2 (late Precambrian-Lower Ordovician) is composed of shales and sandstones with minor limestones. The base of this unit is composed of the Triad, or the Eocambrian glacial deposits that can be correlated across west Africa. Unit 3 (Upper Oedovician-Devonian) is composed of a variety of lithofacies varying from a basal glacial unit through basinal graptolitic shales into shallow marine/continental deposits. Each of these units will be discussed in detail and the petroleum potential of the constituent lithofacies considered.

  12. Climate Variability and Predictability in North West Africa

    NASA Astrophysics Data System (ADS)

    Baddour, O.; Djellouli, Y.

    2003-04-01

    North West Africa defined here as the area including Morocco, Algeria and Tunisia, it occupies a large territory in North Africa with more than 3.5 Millions KM2. The geographical contrast is very important: while most of the southern part is desert, the northern and north western part exhibits a contrasting geography including large flat areas in the western part of Morocco, northern Algeria and eastern part of Tunisia, And also the formidable Atlas mountains barrier that extends from south west of Morocco toward north west of Tunisia crossing central Morocco and north Algeria.Agriculture is one of major socio-economic activity in the region with an extensive cash-crop for exporting to Europe especially from Morocco and Tunisia. The influence of the recurring droughts during 80s and 90s was very crucial for the economic and societal aspects of the region. In Morocco, severe droughts has caused GDP fluctuation within past 20 years from 10% increase down to negative values in some particular years. Most of weather systems occurs during frontal excursion through the Atlantic and Europe bringing cold air and cloud and precipitation systems. The active precipitation period extends from October to May with almost 80% of the total rainfall. The dry season extends from June to September. Nevertheless some convective clouds develop occasionally during the dry season due to subtropical humid air mass that converge into the region and trigger the convection especially in the high area and Sahara. These less frequent precipitation systems could lead to weather hazards such as flash floods with damage to population and infrastructure. (The example of OURIKA in August 1995 in Morocco). The far south of the region experiences some tropical influence during August period especially in the south of Algeria when the ITCZ can migrate from the SAHEL area to its northernmost position in the region. Recent studies have investigated seasonal rainfall variability and prediction over

  13. South Africa

    NASA Technical Reports Server (NTRS)

    2002-01-01

    This true-color image of South Africa was acquired on May 14, 2000, by NASA's Moderate-resolution Imaging Spectroradiometer, or MODIS. The image was produced using a combination of the sensor's 250-m and 500-m resolution visible wavelength bands. As part of the opening ceremony to begin the joint U.S.-South Africa SAFARI Field Experiment, NASA presented print copies of this image as GIFts to Dr. Ben Ngubane, Minister of Arts, Science and Technology, and Honorable Advocate Ngoaka Ramathlodi, Premier of the Northern Province, South Africa. The area shown in this image encompasses seven capital cities and a number of the region's distinctive geological features can be seen clearly. Toward the northern (top) central part of the image, the browns and tans comprise the Kalahari Desert of southern Botswana. The Tropic of Capricorn runs right through the heart of the Kalahari and the Botswanan capital city of Gaborone sits on the Limpopo River, southeast of the Kalahari. Along the western coastline of the continent is the country of Namibia, where the Namib Desert is framed against the sea by the Kaokoveld Mountains. The Namibian capital of Windhoek is obscured by clouds. Looking closely in the center of the image, the Orange River can be seen running from east to west, demarcating the boundary between Namibia and South Africa. On the southwestern corner of the continent is the hook-like Cape of Good Hope peninsula and Cape Town, the parliamentary capital of South Africa. Running west to east away from Cape Town are the Great Karroo Mountains. The shadow in this image conveys a sense of the very steep grade of the cliffs along the southern coast of South Africa. Port Elizabeth sits on the southeasternmost point of South Africa, and a large phytoplankton bloom can be seen in the water about 100 miles east of there. Moving northward along the east coast, the Drakensberg Mountains are visible. The two small nations of Lesotho and Swaziland are in this region, completely

  14. Estimation of Croplands in West Africa using Global Land Cover and Land Use Datasets: Preliminary Results

    NASA Astrophysics Data System (ADS)

    Adhikari, P.; de Beurs, K.

    2013-12-01

    Africa is vulnerable to the effects of global climate change resulting in reduced agricultural production and worsening food security. Studies show that Africa has the lowest cereal yield compared to other regions of the world. The situation is particularly dire in East, Central and West Africa. Despite their low cereal yield, the population of East, Central and West Africa has doubled between 1980 and 2007. Furthermore, West Africa has a history of severe and long droughts which have occasionally caused widespread famine. To understand how global climate change and land cover change have impacted crop production (yield) it is important to estimate croplands in the region. The objective of this study is to compare ten publicly available land cover and land use datasets, covering different time periods, to estimate croplands in West Africa. The land cover and land use data sets used cover the period from early 1990s to 2010. Preliminary results show a high variability in cropland estimates. For example, in Benin, the estimated cropland area varies from 2.5 to 21% of the total area, while it varies from 3 to 8% in Niger. Datasets with a finer resolution (≤ 1,000 m) have consistently estimated comparable cropland areas across all countries. Several categorical verification statistics such as probability of detection (POD), false alarm ratio (FAR) and critical success index are also used to analyze the correspondence between estimated and observed cropland pixels at the scales of 1 Km and 10 Km.

  15. Emission and deposition of Nitrogen compounds in West Africa

    NASA Astrophysics Data System (ADS)

    Delon, C.; Galy-Lacaux, C.; Adon, M.; Liousse, C.

    2010-12-01

    The atmospheric nitrogen budget depends on emission and deposition fluxes both as reduced and oxidized compounds. In West African ecosystems, data are scarce, and establishing a N budget is not an easy task. This work aims at linking data from diverse origins (surface, aircraft measurements, satellite data, modelling) to estimate emissions and deposition of N compounds in dry and wet savannas of West Africa, and to study their impact on atmospheric chemistry. In remote areas like in the Sahel, N oxidised compounds emissions are dominated by NO biogenic emissions from soils. N emissions from anthropogenic sources (biomass burning, domestic fires, fossil fuel) are less important, due to the low quantity of vegetation, and to the remoteness of big cities. N reduced compounds emissions are dominated by the release of NH3 from cattle dung. Biogenic NO emissions from soils have a direct impact on NOx and O3 concentration increase in the lower troposphere, as shown by results from aircraft and surface measurements, and from modelling (coupled dynamics/chemistry MESONH-C model, with on line emission derived from a neural network algorithm, where the NO flux is dependent on water field pore space, surface and deep soil temperature, sand percentage, pH, fertilization rate and wind speed), in the area of Niamey (Niger) in August 2006. In a second part of this work, estimated emissions of both oxidised and reduced N compounds are compared to estimate dry and wet deposition fluxes for the year 2006 in the Sahel region. The dry deposition flux is the product of modelled dry deposition velocity and the measured concentration. Concentrations have been measured in 3 stations located in dry savanna ecosystem) within the IDAF (IGAC/DEBITS/Africa) network, and dry deposition velocities have been modelled with the surface model ISBA. A first tentative of budget has been calculated for the year 2006, trying to integrate all potentially known sources and sinks in the region. Finally, the

  16. Response of the Water Cycle of West Africa and Atlantic to Radiative Forcing by Saharan Dust

    NASA Technical Reports Server (NTRS)

    Lau, K. M.; Kim, Kyu-Myong; Sud, Yogesh C.; Walker, Gregory L.

    2010-01-01

    The responses of the atmospheric water cycle and climate of West Africa and the Atlantic to radiative forcing of Saharan dust are studied using the NASA finite volume general circulation model (fvGCM), coupled to a mixed layer ocean. We find evidence in support of the "elevated heat pump" (EHP) mechanism that underlines the responses of the atmospheric water cycle to dust forcing as follow. During the boreal summer, as a result of large-scale atmospheric feed back triggered by absorbing dust aerosols, rainfall and cloudiness are enhanced over the West Africa/Easter Atlantic ITCZ, and suppressed over the West Atlantic and Caribbean. region. Shortwave radiation absorption by dust warms the atmosphere and cools the surface, while long wave has the opposite response. The elevated dust layer warms the air over Nest Africa and the eastern Atlantic. The condensation heating associated with the induced deep convection drives and maintains an anomalous large-scale east-west overturning circulation with rising motion over West Africa/eastern Atlantic, and sinking motion over the Caribbean region. The response also includes a strengthening of the West African monsoon, manifested in northward shift of the West Africa precipitation over land, increased low-level westerlies flow over West Africa at the southern edge of the dust layer, and a near surface energy fluxes, resulting in cooling of the Nest African land and the eastern Atlantic, and a warming in the West Atlantic and Caribbean. The EHP effect is most effective for moderate to highly absorbing dusts, and becomes minimized for reflecting dust with single scattering albedo at 0.95 or higher.

  17. Fluid inclusions in quartz crystals from South-West Africa

    USGS Publications Warehouse

    Kvenvolden, K.A.; Roedder, E.

    1971-01-01

    Quartz crystals from calcite veins of unknown age in Precambrian metasedimentary rocks at Geiaus No. 6 and Aukam farms in South-West Africa contain both primary and secondary inclusions filled with one or a variable combination of: organic liquid, moderately saline aqueous liquid, dark-colored solid, and vapor. Analysis of these materials by microscopy and by gas chromatography and mass spectrometry shows the presence of constituents of both low and high molecular weights. The former include CH4, C2H6, C3H8 and possibly C4H10 as well as CO, CO2, H2O, N2 and H2. High molecular weight components are dominantly n-alkanes and isoprenoid hydrocarbons. The n-alkanes range from at least n-C10 to n-C33. Concentrations of n-alkanes larger than n-C17 decrease regularly with increasing carbon number. An homologous series of isoprenoid hydrocarbons ranging from at least C14 to C20 is present in unusually high concentrations. Pristane (C19) is most abundant, and C17 isoprenoid is least abundant. The molecular composition and distribution of hydrocarbons suggest biological precursors for these components. Consideration of data provided by freezing, crushing and heating experiments suggests that the pressures at the time these in part supercritical fluids were trapped probably exceeded 30-40 atm, and the minimum trapping temperature was about 120-160??C. Both primary and secondary inclusions apparently containing only organic materials were trapped by the growth of the host quartz from aqueous solution. The data obtained neither prove nor preclude Precambrian, Paleozoic or younger sources for the organic materials. ?? 1971.

  18. Revisiting evidence for sustainability of bushmeat hunting in West Africa.

    PubMed

    Waite, T A

    2007-09-01

    Bushmeat hunting, a key source of dietary protein, has been implicated as a major extinction threat to tropical vertebrate species in West Africa. Ideally, any such hunting of wild species should be done sustainably, with off-take levels low enough to ensure viability of harvested species. Recent work purports to show that a mature bushmeat market in a major city in Ghana operates sustainably after depletion of vulnerable, slow-reproducing species (Cowlishaw and others 2005). I revisit two aspects of this work. First, I retest the prediction that larger species are transported to the market from greater distances, as expected if overexploitation depletes large species close to the city. Cowlishaw and others failed to find a significantly positive relationship between species-specific body mass and distance between capture site and the market. However, my reanalysis provides evidence for a positive relationship after all, consistent with unsustainable harvesting. In particular, ungulate species were harvested significantly farther from the market than smaller-bodied rodent species. Second, I caution that just because species "persist" in the marketplace in no way implies that they can withstand hunting pressure elsewhere and so should be of little concern to conservationists. I reveal that such species, despite their high intrinsic rates of population growth, are not robust elsewhere. Several of them have disappeared from a network of protected areas in Ghana (Brashares and others 2001). I show that faster-reproducing species are not necessarily more likely to persist in protected areas. The mere presence of fast-reproducing species in a mature bushmeat market should not be construed as generalizable robustness; criteria for ecological sustainability should ensure viability; and harvested species should be robust, not highly prone to extinction, in protected areas.

  19. Silicone wristbands detect individuals' pesticide exposures in West Africa

    PubMed Central

    Scott, Richard P.; Blaustein, Kathy L.; Halbleib, Mary L.; Sarr, Makhfousse; Jepson, Paul C.

    2016-01-01

    We detected between 2 and 10 pesticides per person with novel sampling devices worn by 35 participants who were actively engaged in farming in Diender, Senegal. Participants were recruited to wear silicone wristbands for each of two separate periods of up to 5 days. Pesticide exposure profiles were highly individualized with only limited associations with demographic data. Using a 63-pesticide dual-column gas chromatography–electron capture detector (GC-ECD) method, we detected pyrethoid insecticides most frequently, followed by organophosphate pesticides which have been linked to adverse health outcomes. This work provides the first report of individualized exposure profiles among smallholder farmers in West Africa, where logistical and practical constraints have prevented the use of more traditional approaches to exposure assessment in the past. The wristbands and associated analytical method enabled detection of a broad range of agricultural, domestic, legacy and current-use pesticides, including esfenvalerate, cypermethrin, lindane, DDT and chlorpyrifos. Participants reported the use of 13 pesticide active ingredients while wearing wristbands. All six of the pesticides that were both reportedly used and included in the analytical method were detected in at least one wristband. An additional 19 pesticide compounds were detected beyond those that were reported to be in use, highlighting the importance of measuring exposure in addition to collecting surveys and self-reported use records. The wristband method is a candidate for more widespread use in pesticide exposure and health monitoring, and in the development of evidence-based policies for human health protection in an area where food security concerns are likely to intensify agricultural production and pesticide use in the near future. PMID:27853621

  20. Spatiotemporal Analysis of the 2014 Ebola Epidemic in West Africa

    PubMed Central

    Backer, Jantien A.; Wallinga, Jacco

    2016-01-01

    In 2014–2016, Guinea, Sierra Leone and Liberia in West Africa experienced the largest and longest Ebola epidemic since the discovery of the virus in 1976. During the epidemic, incidence data were collected and published at increasing resolution. To monitor the epidemic as it spread within and between districts, we develop an analysis method that exploits the full spatiotemporal resolution of the data by combining a local model for time-varying effective reproduction numbers with a gravity-type model for spatial dispersion of the infection. We test this method in simulations and apply it to the weekly incidences of confirmed and probable cases per district up to June 2015, as reported by the World Health Organization. Our results indicate that, of the newly infected cases, only a small percentage, between 4% and 10%, migrates to another district, and a minority of these migrants, between 0% and 23%, leave their country. The epidemics in the three countries are found to be similar in estimated effective reproduction numbers, and in the probability of importing infection into a district. The countries might have played different roles in cross-border transmissions, although a sensitivity analysis suggests that this could also be related to underreporting. The spatiotemporal analysis method can exploit available longitudinal incidence data at different geographical locations to monitor local epidemics, determine the extent of spatial spread, reveal the contribution of local and imported cases, and identify sources of introductions in uninfected areas. With good quality data on incidence, this data-driven method can help to effectively control emerging infections. PMID:27930675

  1. Land-use change and infectious disease in West Africa

    NASA Astrophysics Data System (ADS)

    Thomson, M. C.; Ericksen, P. J.; Mohamed, A. Ben; Connor, S. J.

    Land-use change has been associated with changes in the dynamics of infectious disease in West Africa. Here we describe the complex interactions of land-use change with three diseases (both vector- and non-vector-borne) of considerable public health significance in this region, namely, malaria and irrigation; epidemic meningitis and land degradation; onchocerciasis and deforestation. We highlight the confounding effect of climate variability, which acts as a driver of both land-use change and human health. We conclude, as have others, that the scale of observation always matters, and complex and dynamic feedbacks among social-ecological systems are not easily teased apart. We suggest that in order to establish the causal chain of interactions between land-use change and human health outcomes two approaches are necessary. The first is to have a thorough understanding of the aetiology of disease and the specific mechanisms by which land-use and climate variability affect the transmission of pathogens. This is achieved by focused, detailed studies encompassing a wide range of potential drivers, which are inevitably small scale and often cover short time periods. The second consists of large-scale studies of statistical associations between transmission indices or health outcomes and environmental variables stratified by known ecological or socio-economic confounders, and sufficient in size to overcome local biases in results. Such research activities need to be designed to inform each other if we are to develop predictive models for monitoring these diseases and to develop integrated programs for human health and sustainable land use.

  2. Criminal fisheries practices and their perverse effects in West Africa

    NASA Astrophysics Data System (ADS)

    Sall, Aliou; Nauen, Cornelia E.

    2017-04-01

    Enforcing sustainable use of natural resources is a challenging task for developing countries, although modern earth observation technologies can help. Exploitation of marine living resources is a very demanding show-case for lessons about the problem as well as for insights into possible remedies. The extent of illegal, unreported and unregulated fishing reaches very high proportions in West Africa and accounts for approximately half of total extractions according to most recent independent research results by the Sea Around Us Project. Based on field research in Senegal and neighbouring countries, we argue that the scale of illegal practices, needs to be classified as criminal and no longer as a fisheries management problem. The perpetrators are mostly international industrial fleets operating across borders alternating between organised crime and activities within legitimate agreements. This makes persecution particularly difficult for under-resourced authorities in developing countries with insufficient means for monitoring, control and surveillance (MCS) and little capacity to use earth observation technology to track exploitation patterns. The net results are firstly significant financial losses for the countries, estimated elsewhere for West African countries except Namibia at US 1.7 billion for the period 2000 to 2010. The perverse social, institutional and environmental effects may even turn out to be more far-reaching. Among these are the reduction of women entrepreneurs in the dynamic local small-scale fishing industry to low-paid labour in industrial processing plants, break down of traditional solidarity chains within the small-scale sector under excessive economic pressure from industrial competition, corruption and other forms of delegitimisation of public institutions and degradation of the marine ecosystems with serious effects on local food security. We discuss these effects in the light of field research carried out mostly in Senegal and

  3. Autosomal and mtDNA Markers Affirm the Distinctiveness of Lions in West and Central Africa.

    PubMed

    Bertola, Laura D; Tensen, Laura; van Hooft, Pim; White, Paula A; Driscoll, Carlos A; Henschel, Philipp; Caragiulo, Anthony; Dias-Freedman, Isabela; Sogbohossou, Etotépé A; Tumenta, Pricelia N; Jirmo, Tuqa H; de Snoo, Geert R; de Iongh, Hans H; Vrieling, Klaas

    2015-01-01

    The evolutionary history of a species is key for understanding the taxonomy and for the design of effective management strategies for species conservation. The knowledge about the phylogenetic position of the lion (Panthera leo) in West/Central Africa is largely based on mitochondrial markers. Previous studies using mtDNA only have shown this region to hold a distinct evolutionary lineage. In addition, anthropogenic factors have led to a strong decline in West/Central African lion numbers, thus, the conservation value of these populations is particularly high. Here, we investigate whether autosomal markers are concordant with previously described phylogeographic patterns, and confirm the unique position of the West/Central African lion. Analysis of 20 microsatellites and 1,454 bp of the mitochondrial DNA in 16 lion populations representing the entire geographic range of the species found congruence in both types of markers, identifying four clusters: 1) West/Central Africa, 2) East Africa, 3) Southern Africa and 4) India. This is not in line with the current taxonomy, as defined by the IUCN, which only recognizes an African and an Asiatic subspecies. There are no indications that genetic diversity in West/Central Africa lions is lower than in either East or Southern Africa, however, given this genetic distinction and the recent declines of lion numbers in this region, we strongly recommend prioritization of conservation projects in West/Central Africa. As the current taxonomic nomenclature does not reflect the evolutionary history of the lion, we suggest that a taxonomic revision of the lion is warranted.

  4. Autosomal and mtDNA Markers Affirm the Distinctiveness of Lions in West and Central Africa

    PubMed Central

    Bertola, Laura D.; Tensen, Laura; van Hooft, Pim; White, Paula A.; Driscoll, Carlos A.; Henschel, Philipp; Caragiulo, Anthony; Dias-Freedman, Isabela; Sogbohossou, Etotépé A.; Tumenta, Pricelia N.; Jirmo, Tuqa H.; de Snoo, Geert R.

    2015-01-01

    The evolutionary history of a species is key for understanding the taxonomy and for the design of effective management strategies for species conservation. The knowledge about the phylogenetic position of the lion (Panthera leo) in West/Central Africa is largely based on mitochondrial markers. Previous studies using mtDNA only have shown this region to hold a distinct evolutionary lineage. In addition, anthropogenic factors have led to a strong decline in West/Central African lion numbers, thus, the conservation value of these populations is particularly high. Here, we investigate whether autosomal markers are concordant with previously described phylogeographic patterns, and confirm the unique position of the West/Central African lion. Analysis of 20 microsatellites and 1,454 bp of the mitochondrial DNA in 16 lion populations representing the entire geographic range of the species found congruence in both types of markers, identifying four clusters: 1) West/Central Africa, 2) East Africa, 3) Southern Africa and 4) India. This is not in line with the current taxonomy, as defined by the IUCN, which only recognizes an African and an Asiatic subspecies. There are no indications that genetic diversity in West/Central Africa lions is lower than in either East or Southern Africa, however, given this genetic distinction and the recent declines of lion numbers in this region, we strongly recommend prioritization of conservation projects in West/Central Africa. As the current taxonomic nomenclature does not reflect the evolutionary history of the lion, we suggest that a taxonomic revision of the lion is warranted. PMID:26466139

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

    NASA Astrophysics Data System (ADS)

    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.

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

    PubMed

    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.

  7. What Factors Might Have Led to the Emergence of Ebola in West Africa?

    PubMed Central

    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. PMID:26042592

  8. A Multivariate Analysis of Freshwater Variability over West Africa

    NASA Astrophysics Data System (ADS)

    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

  9. Groundwater Exploration for Rural Communities in Ghana, West Africa

    NASA Astrophysics Data System (ADS)

    McKay, W. A.

    2001-05-01

    Exploration for potable water in developing countries continues to be a major activity, as there are more than one billion people without access to safe drinking water. Exploration for groundwater becomes more critical in regions where groundwater movement and occurrence is controlled by secondary features such as fractures and faults. Drilling success rates in such geological settings are generally very low, but can be improved by integrating geological, hydrogeological, aerial photo interpretation with land-based geophysical technology in the selection of drilling sites. To help alleviate water supply problems in West Africa, the Conrad N. Hilton Foundation and other donors, since 1990, have funded the World Vision Ghana Rural Water Project (GRWP) to drill wells for potable water supplies in the Greater Afram Plains (GAP) of Ghana. During the first two years of the program, drilling success rates using traditional methods ranged from 35 to 80 percent, depending on the area. The average drilling success rate for the program was approximately 50 percent. In an effort to increase the efficiency of drilling operations, the Desert Research Institute evaluated and developed techniques for application to well-siting strategies in the GAP area of Ghana. A critical project element was developing technical capabilities of in-country staff to independently implement the new strategies. Simple cost-benefit relationships were then used to evaluate the economic advantages of developing water resources using advanced siting methods. The application of advanced methods in the GAP area reveal an increase of 10 to 15 percent in the success rate over traditional methods. Aerial photography has been found to be the most useful of the imagery products covering the GAP area. An effective approach to geophysical exploration for groundwater has been the combined use of EM and resistivity methods. Economic analyses showed that the use of advanced methods is cost-effective when success

  10. Risk maps of Lassa fever in West Africa.

    PubMed

    Fichet-Calvet, Elisabeth; Rogers, David John

    2009-01-01

    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. 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 neither vegetation nor altitude seemed particularly important

  11. Risk Maps of Lassa Fever in West Africa

    PubMed Central

    Fichet-Calvet, Elisabeth; Rogers, David John

    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 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 absence∶presence clusters were used in each of Models 2 and 3, the 2 absence∶1 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 neither vegetation nor

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

    NASA Astrophysics Data System (ADS)

    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.

  13. Ebola in West Africa--CDC's Role in Epidemic Detection, Control, and Prevention.

    PubMed

    Frieden, Thomas R; Damon, Inger K

    2015-11-01

    Since Ebola virus disease was identified in West Africa on March 23, 2014, the Centers for Disease Control and Prevention (CDC) has undertaken the most intensive response in the agency's history; >3,000 staff have been involved, including >1,200 deployed to West Africa for >50,000 person workdays. Efforts have included supporting incident management systems in affected countries; mobilizing partners; and strengthening laboratory, epidemiology, contact investigation, health care infection control, communication, and border screening in West Africa, Nigeria, Mali, Senegal, and the United States. All efforts were undertaken as part of national and global response activities with many partner organizations. CDC was able to support community, national, and international health and public health staff to prevent an even worse event. The Ebola virus disease epidemic highlights the need to strengthen national and international systems to detect, respond to, and prevent the spread of future health threats.

  14. Morbidity and Mortality Due to Bordetella pertussis: A Significant Pathogen in West Africa?

    PubMed Central

    Kampmann, Beate; Mackenzie, Grant

    2016-01-01

    In the absence of specific surveillance platforms for pertussis and availability of suitable diagnostics at the hospital level, reliable data that describe morbidity and mortality from pertussis are difficult to obtain in any setting, as is the case in West Africa. Here, we summarize the available evidence of the burden of pertussis in the region, given historical data, and describe recent and ongoing epidemiological studies that offer opportunities for additional data collection. The available seroepidemiological data provide evidence of ongoing circulation of Bordetella pertussis in the region. Due to the lack of systematic and targeted surveillance with laboratory confirmation of B. pertussis infection, we cannot definitively conclude that pertussis disease is well controlled in West Africa. However, based on observations by clinicians and ongoing demographic surveillance systems that capture morbidity and mortality data in general terms, currently there is no evidence that pertussis causes a significant burden of disease in young children in West Africa. PMID:27838666

  15. Islam in Africa

    DTIC Science & Technology

    2008-05-09

    orders as well as followers in West Africa and Sudan, and, like other orders, strives to know God through meditation and emotion. Sufis may be Sunni or...Shi’ite, and their ceremonies may involve chanting, music, dancing, and meditation . West Africa and Sudan have various Sufi orders regarded

  16. Trichinella britovi etiological agent of sylvatic trichinellosis in the Republic of Guinea (West Africa) and a re-evaluation of geographical distribution for encapsulated species in Africa.

    PubMed

    Pozio, E; Pagani, P; Marucci, G; Zarlenga, D S; Hoberg, E P; De Meneghi, D; La Rosa, G; Rossi, L

    2005-08-01

    In West Africa, Trichinella infection was documented in humans and animals from Senegal in the 1960s, and the biological characters of one isolate showed a lower infectivity to domestic pigs and rodents when compared with that of a Trichinella spiralis pig isolate from Europe. To identify the Trichinella species present in West Africa, a survey was conducted in a total of 160 wild animals in the Republic of Guinea. Three Viverridae, one true civet (Viverra civetta) and two African palm civets (Nandinia binotata) from the Fouta Djallon Massif, Pilimini Subprefecture, were found positive by artificial digestion of muscle samples. Trichinella larvae from these three viverrids were identified as Trichinella britovi and no difference was detected in three examined sequences from these African isolates and the reference strain of T. britovi from Europe, indicating common ancestry, an historically continuous geographic distribution, and recent isolation for African and European populations. The detection of T. britovi in West Africa modifies our knowledge about the distribution of encapsulated species of Trichinella in Africa. Thus, Trichinella nelsoni is now considered to have a distribution limited to the Eastern part of the Afrotropical region from Kenya to South Africa. This provides a plausible explanation for the presence of Trichinella T8 in Namibia and South Africa, and further suggests that T. britovi could be the Trichinella species circulating among wild animals of Northern Africa.

  17. The WASCAL high-resolution climate projection ensemble for West Africa

    NASA Astrophysics Data System (ADS)

    Kunstmann, Harald; Heinzeller, Dominikus; Dieng, Diarra; Smiatek, Gerhard; Bliefernicht, Jan; Hamann, Ilse; Salack, Seyni

    2017-04-01

    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. We perform ensemble-based regional climate simulations at a high resolution of 12km for West Africa to allow a scientifically sound derivation of climate change adaptation measures. Based on the RCP4.5 scenario, our ensemble consist of three simulation experiments with the Weather Research & Forecasting Tool (WRF) and one additional experiment with the Consortium for Small-scale Modelling Model COSMO in Climate Mode (COSMO-CLM). We discuss the model performance over the validation period 1980-2010, including a novel, station-based precipitation database for West Africa obtained within the WASCAL (West African Science Service Centre for Climate Change and Adapted Land Use) program. 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 for the two future periods 2020-2050 and 2070-2100 and compare them to current state-of-the-art projections from the CORDEX-Africa project. While the temperature change signal is similar to that obtained within CORDEX-Africa, our simulations predict a wetter future for the Coast of Guinea and the southern Soudano area and a slight drying in the northernmost part of the Sahel.

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

    PubMed Central

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

    2016-01-01

    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. PMID:28007834

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

    PubMed

    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.

  20. Deconstructing "malaria": West Africa as the next front for dengue fever surveillance and control.

    PubMed

    Stoler, Justin; Al Dashti, Rawan; Anto, Francis; Fobil, Julius N; Awandare, Gordon A

    2014-06-01

    Presumptive treatment of febrile illness patients for malaria remains the norm in endemic areas of West Africa, and "malaria" remains the top source of health facility outpatient visits in many West African nations. Many other febrile illnesses, including bacterial, viral, and fungal infections, share a similar symptomatology as malaria and are routinely misdiagnosed as such; yet growing evidence suggests that much of the burden of febrile illness is often not attributable to malaria. Dengue fever is one of several viral diseases with symptoms similar to malaria, and the combination of rapid globalization, the long-standing presence of Aedes mosquitoes, case reports from travelers, and recent seroprevalence surveys all implicate West Africa as an emerging front for dengue surveillance and control. This paper integrates recent vector ecology, public health, and clinical medicine literature about dengue in West Africa across community, regional, and global geographic scales. We present a holistic argument for greater attention to dengue fever surveillance in West Africa and renew the call for improving differential diagnosis of febrile illness patients in the region.

  1. Prevalence, determinants and systems-thinking approaches to optimal hypertension control in West Africa.

    PubMed

    Iwelunmor, Juliet; Airhihenbuwa, Collins O; Cooper, Richard; Tayo, Bamidele; Plange-Rhule, Jacob; Adanu, Richard; Ogedegbe, Gbenga

    2014-05-21

    In West Africa, hypertension, once rare, has now emerged as a critical health concern and the trajectory is upward and factors are complex. The true magnitude of hypertension in some West African countries, including in-depth knowledge of underlying risk factors is not completely understood. There is also a paucity of research on adequate systems-level approaches designed to mitigate the growing burden of hypertension in the region. In this review, we thematically synthesize available literature pertaining to the prevalence of hypertension in West Africa and discuss factors that influence its diagnosis, treatment and control. We aimed to address the social and structural determinants influencing hypertension in the sub-region including the effects of urbanization, health infrastructure and healthcare workforce. The prevalence of hypertension in West Africa has increased over the past decade and is rising rapidly with an urban-rural gradient that places higher hypertension prevalence on urban settings compared to rural settings. Overall levels of awareness of one's hypertension status remain consistently low in West African. Structural and economic determinants related to conditions of poverty such as insufficient finances have a direct impact on adherence to prescribed antihypertensive medications. Urbanization contributes to the increasing incidence of hypertension in the sub-region and available evidence indicates that inadequate health infrastructure may act as a barrier to optimal hypertension control in West Africa. Given that optimal hypertension control in West Africa depends on multiple factors that go beyond simply modifying the behaviors of the individuals alone, we conclude by discussing the potential role systems-thinking approaches can play to achieve optimal control in the sub-region. In the context of recent advances in hypertension management including new therapeutic options and innovative solutions to expand health workforce so as to meet the high

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

    PubMed

    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

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

    PubMed

    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).

  4. The Ebola epidemic in West Africa: challenges, opportunities, and policy priority areas.

    PubMed

    Buseh, Aaron G; Stevens, Patricia E; Bromberg, Mel; Kelber, Sheryl T

    2015-01-01

    The ongoing Ebola epidemic in West Africa has drawn attention to global health inequalities, in particular the inadequacies of health care systems in sub-Saharan African countries for appropriately managing and containing infectious diseases. The purpose of this article is to examine the sociopolitical and economic conditions that created the environment for the Ebola epidemic to occur, identify challenges to and opportunities for the prevention and control of Ebola and future outbreaks, and discuss policy recommendations and priority areas for addressing the Ebola epidemic and future outbreaks in West Africa. Articles in peer-reviewed journals on health system reforms in developing countries and periodicals of international organizations were used to gather the overview reported in this article. We identify individual, structural, and community challenges that must be addressed in an effort to reduce the spread of Ebola in West Africa. The Ebola epidemic in West Africa underscores the need for the overhaul and transformation of African health care systems to build the capacity in these countries to address infectious diseases. Public-private partnerships for investment in developing countries' health care systems that involve the international community are critical in addressing the current Ebola epidemic and future outbreaks.

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

    ERIC Educational Resources Information Center

    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…

  6. School Leadership in West Africa: Findings from a Systematic Literature Review

    ERIC Educational Resources Information Center

    Bush, Tony; Glover, Derek

    2016-01-01

    The literature shows that leadership is the second most important factor influencing school and learner outcomes, including levels of literacy and numeracy, school leaving examination results, and progression to secondary and higher education. This article focuses on school leadership in West Africa, drawing on a systematic review of the academic…

  7. Systemic Evaluation of Advisory Services to Family Farms in West Africa

    ERIC Educational Resources Information Center

    Faure, Guy; Rebuffel, Pierre; Violas, Dominique

    2011-01-01

    In West Africa, advisory services for family farms have been promoted to better address producers' needs. The paper aims to show that these services can be understood as a system whose functioning is strongly determined by the financing mechanisms, the governance mechanisms put in place, the quality of human resources delivering advice, and the…

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

    ERIC Educational Resources Information Center

    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…

  9. Rural Development in Africa: A Bibliography (Part II: North, South, West). Training & Methods Series, Number 17.

    ERIC Educational Resources Information Center

    Wisconsin Univ., Madison. Land Tenure Center.

    Compiled in December 1971, this bibliography lists approximately 940 books, journals, periodicals, and unpublished mimeographs dealing with rural development in north, west, and southern Africa. All materials are dated between 1953 and 1971. Entries are listed by country under the following headings: agriculture, economic affairs, social affairs,…

  10. Traditional Apprenticeship in West Africa: Recent Evidence and Policy Options. Discussion Paper No. 34.

    ERIC Educational Resources Information Center

    Fluitman, Fred

    Apprenticeship is the main avenue to self-employment in micro-enterprises and thus a cornerstone of informal sector development in West Africa. Survey results for Ibadan, Lome, Dakar, Niamey, and other cities demonstrate that apprenticeship as practiced by informal sector artisans is often very similar from one country to the next. Dropout rates…

  11. The Contribution of the Society of the Holy Child Jesus to Catholic Education in West Africa

    ERIC Educational Resources Information Center

    Aidoo, Philomena

    2016-01-01

    This article discusses the extent to which the charism and the philosophy of education of Venerable Cornelia Connelly founder of the Society of the Holy Child Jesus are being maintained in the twenty-first century in West Africa (Nigeria and Ghana). Using data gathered from Sisters and former students of Holy Child schools as evidence it seeks to…

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

    ERIC Educational Resources Information Center

    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…

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

    ERIC Educational Resources Information Center

    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…

  14. The Association between Bullying and Psychological Health among Senior High School Students in Ghana, West Africa

    ERIC Educational Resources Information Center

    Owusu, Andrew; Hart, Peter; Oliver, Brittney; Kang, Minsoo

    2011-01-01

    Background: School-based bullying, a global challenge, negatively impacts the health and development of both victims and perpetrators. This study examined the relationship between bullying victimization and selected psychological variables among senior high school (SHS) students in Ghana, West Africa. Methods: This study utilized data from the…

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

    ERIC Educational Resources Information Center

    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…

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

    PubMed

    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.

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

    NASA Astrophysics Data System (ADS)

    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.

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

    DTIC Science & Technology

    2013-05-01

    UN’s former Special Representative of the Secretary General for West Africa, Somalia, and Burundi —stated in a February 2012 interview that... GDP ) is unknown. Most analysts, however, conclude that being a drug transit state is, on net, very detrimental to a country’s devel- opment.241

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

    ERIC Educational Resources Information Center

    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…

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

    ERIC Educational Resources Information Center

    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…

  1. The Contribution of the Society of the Holy Child Jesus to Catholic Education in West Africa

    ERIC Educational Resources Information Center

    Aidoo, Philomena

    2016-01-01

    This article discusses the extent to which the charism and the philosophy of education of Venerable Cornelia Connelly founder of the Society of the Holy Child Jesus are being maintained in the twenty-first century in West Africa (Nigeria and Ghana). Using data gathered from Sisters and former students of Holy Child schools as evidence it seeks to…

  2. School Leadership in West Africa: Findings from a Systematic Literature Review

    ERIC Educational Resources Information Center

    Bush, Tony; Glover, Derek

    2016-01-01

    The literature shows that leadership is the second most important factor influencing school and learner outcomes, including levels of literacy and numeracy, school leaving examination results, and progression to secondary and higher education. This article focuses on school leadership in West Africa, drawing on a systematic review of the academic…

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

    ERIC Educational Resources Information Center

    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…

  4. Apollo 4 Mission - Atlantic Ocean,coastal Brazil and West Africa

    NASA Image and Video Library

    1967-11-09

    AS04-01-200 (9 Nov. 1967) --- Coastal Brazil, Atlantic Ocean, West Africa, Sahara, looking northwest, as photographed from the unmanned Apollo 4 (Spacecraft 017/Saturn 501) earth-orbital space mission. This picture was taken when the Spacecraft 017 and the Saturn IVB stage were orbiting Earth at an altitude of 9,060 nautical miles.

  5. Rural Development in Africa: A Bibliography (Part II: North, South, West). Training & Methods Series, Number 17.

    ERIC Educational Resources Information Center

    Wisconsin Univ., Madison. Land Tenure Center.

    Compiled in December 1971, this bibliography lists approximately 940 books, journals, periodicals, and unpublished mimeographs dealing with rural development in north, west, and southern Africa. All materials are dated between 1953 and 1971. Entries are listed by country under the following headings: agriculture, economic affairs, social affairs,…

  6. The Association between Bullying and Psychological Health among Senior High School Students in Ghana, West Africa

    ERIC Educational Resources Information Center

    Owusu, Andrew; Hart, Peter; Oliver, Brittney; Kang, Minsoo

    2011-01-01

    Background: School-based bullying, a global challenge, negatively impacts the health and development of both victims and perpetrators. This study examined the relationship between bullying victimization and selected psychological variables among senior high school (SHS) students in Ghana, West Africa. Methods: This study utilized data from the…

  7. Vulnerability to changes in malaria transmission due to climate change in West Africa

    NASA Astrophysics Data System (ADS)

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

    2012-12-01

    Malaria transmission in West Africa is strongly tied to climate; temperature affects the development rate of the malaria parasite, as well as the survival of the mosquitoes that transmit the disease, and rainfall is tied to mosquito abundance, as the vector lays its eggs in rain-fed water pools. As a result, the environmental suitability for malaria transmission in this region is expected to change as temperatures rise and rainfall patterns are altered. The vulnerability to changes in transmission varies throughout West Africa. Areas where malaria prevalence is already very high will be less sensitive to changes in transmission. Increases in environmental suitability for malaria transmission in the most arid regions may still be insufficient to allow sustained transmission. However, areas were malaria transmission currently occurs at low levels are expected to be the most sensitive to changes in environmental suitability for transmission. Here, we use data on current environment and malaria transmission rates to highlight areas in West Africa that we expect to be most vulnerable to an increase in malaria under certain climate conditions. We then analyze climate predictions from global climate models in vulnerable areas, and make predictions for the expected change in environmental suitability for malaria transmission using the Hydrology, Entomology and Malaria Transmission Simulator (HYDREMATS), a mechanistic model developed to simulate village-scale response of malaria transmission to environmental variables in West Africa.

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

    NASA Astrophysics Data System (ADS)

    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.

  9. Mean state and kinematic properties of mesoscale convective systems over West Africa

    NASA Astrophysics Data System (ADS)

    Ogungbenro, Stephen B.; Ajayi, V. O.; Adefolalu, D. O.

    2016-04-01

    A 17-year (1984 to 2000) dataset of brightness temperature (T b) was employed to study the spatial and temporal scales of mesoscale convective systems (MCS) over West Africa. The kinematic properties of MCS were tested using wind products. A threshold brightness temperature (T b) of ≤213 K and spatial coverage specifications of more than 5000 km2 were used as two set criteria for initiating MCS tracking. MCS occurrences vary in seasons and locations over West Africa, and their activities vary with different weather zones. They can appear at any time of the day, but this study revealed a significant preference for early morning hours and night hours over continental West Africa. The well-organized systems occur between July and September in the Sahel, and between May and September in the Savanna band. MCS activities in the Gulf of Guinea peak between March and April, while the Savanna and Sahel zones peak between June and August. The produced annual atlas gives a spatial account of areas of MCS dominance in West Africa. The presence of African Easterly Jet (AEJ) and Tropical Easterly Jet (TEJ), and deep monsoon depth all characterize an environment where MCS thrive. Kinematic study of a typical MCS reveals that the monsoon depth increases at the passage of MCS, with cyclonic vorticity dominating from the surface to 300 hpa while anticyclonic vorticity was observed around 200 hpa, and this confirms the importance of low level convergence and upper level divergence as the major requirements for storm mobilization and maintenance.

  10. Genesis of Major Dust Storms in West Africa during the Summer of 1974

    DTIC Science & Technology

    1986-01-01

    GRANT NUMBER(&) M. Estoque , J. Fernanidez-Partagas, D. M. Helgren and J. M. Prospero DAAG29-83-K-0082 S9. PERFORMING ORGANIZATION NAME AND ADDRESS 10...En’eated) AC~eI>Cn r, GENESIS OF M4AJOR DUST STORMS IN WEST AFRICA DURING THE SUMMER OF 1974 TECHNICAL REPORT M. ESTOQUE , J. FERNANDEZ-PARTAGAS, D.M

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

    SciTech Connect

    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.

  12. Modelling the Potential Impacts of Forestation on Heatwaves over West Africa

    NASA Astrophysics Data System (ADS)

    Odoulami, R. C.; Abiodun, B. J.; Ajayi, A. E.; Diasso, U. J.; Mounkaila Saley, M.

    2016-12-01

    Previous studies have projected climate change impacts on heatwave characteristics over West Africa in future, but without including the influence of ongoing forestation activities in the region. The present study investigates the potential impacts of ongoing forestation activities on heatwave characteristics over West Africa in future. The study used two metrics (excess heat factor (EHF), and a percentile based index (TXI)) to identify and characterise heatwave and a regional climate model (RegCM) to simulate characteristics of heatwave for the past (1970-2000) and future (2030-2060; IPCC RCP4.5) climate in West Africa with and without forestation of the Savannah zone (area between 8°-12°N). While the RCM gives a realistic simulation of extreme temperature thresholds (i.e. 95th percentile of daily mean temperature and 90th percentile of daily maximum temperature) and seasonal distribution of heatwave days, it fails to reproduce the spatial distribution of heatwave number, days and duration as in observation. Both heatwave indices (TXI and EHF) generally produce similar patterns of heatwave characteristics over West Africa, except that heatwave number and days are substantially greater with TXI than EHF. The results also show that the RCP4.5 emission scenario would induce longer and more frequent heatwave events and days over the whole region and that the increase of heatwave days is likely to occur in all months of the year. The results further indicate that forestation would increase the number of heatwave days over the forested zone (Savannah) due to the decrease of albedo. The increase mainly occurs during the dry season when the soil is dryer and the boundary layer maximum temperature and soil temperature increased. Hence, the study shows that using forestation to mitigate the impacts of climate change over West Africa might increase the climate risk on human health and security.

  13. Lessons of Risk Communication and Health Promotion - West Africa and United States.

    PubMed

    Bedrosian, Sara R; Young, Cathy E; Smith, Laura A; Cox, Joanne D; Manning, Craig; Pechta, Laura; Telfer, Jana L; Gaines-McCollom, Molly; Harben, Kathy; Holmes, Wendy; Lubell, Keri M; McQuiston, Jennifer H; Nordlund, Kristen; O'Connor, John; Reynolds, Barbara S; Schindelar, Jessica A; Shelley, Gene; Daniel, Katherine Lyon

    2016-07-08

    During the response to the 2014-2016 Ebola virus disease (Ebola) epidemic in West Africa, CDC addressed the disease on two fronts: in the epidemic epicenter of West Africa and at home in the United States. Different needs drove the demand for information in these two regions. The severity of the epidemic was reflected not only in lives lost but also in the amount of fear, misinformation, and stigma that it generated worldwide. CDC helped increase awareness, promoted actions to stop the spread of Ebola, and coordinated CDC communication efforts with multiple international and domestic partners. CDC, with input from partners, vastly increased the number of Ebola communication materials for groups with different needs, levels of health literacy, and cultural preferences. CDC deployed health communicators to West Africa to support ministries of health in developing and disseminating clear, science-based messages and promoting science-based behavioral interventions. Partnerships in West Africa with local radio, television, and cell phone businesses made possible the dissemination of messages appropriate for maximum effect. CDC and its partners communicated evolving science and risk in a culturally appropriate way to motivate persons to adapt their behavior and prevent infection with and spread of Ebola virus. Acknowledging what is and is not known is key to effective risk communication, and CDC worked with partners to integrate health promotion and behavioral and cultural knowledge into the response to increase awareness of the actual risk for Ebola and to promote protective actions and specific steps to stop its spread. 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).

  14. HIV-1 and HIV-2 infections and AIDS in West Africa.

    PubMed

    De Cock, K M; Brun-Vézinet, F; Soro, B

    1991-01-01

    The authors review advances in HIV-2 research since their last review of the subject, and summarize the current epidemiology of HIV-1 and HIV-2 infections and AIDS in West Africa. West Africa is considered to be comprised of those countries below the Sahara which belong to subregion 1 of the Africa Region as defined by the World Health Organization. Widely varying patterns of disease distribution exist across these countries. The epidemic spread of HIV-1 and HIV-2 in the region is recent, but these infections now occur throughout West Africa. The distribution of the two viral infections is both heterogenous and unstable. It is not clear whether social or biological reasons, or both, account for the apparently less successful epidemic spread of HIV-2. Important epidemiologic questions concerning HIV-2 which await resolution are its incubation period for disease and its efficiency of transmission compared with HIV-1. The authors note that for public health purposes, the two infections should be approached in the same fashion.

  15. [Population growth and global warming: impacts on tsetse and trypanosomoses in West Africa].

    PubMed

    Courtin, F; Sidibé, I; Rouamba, J; Jamonneau, V; Gouro, A; Solano, P

    2009-03-01

    Demographic evolution, climatic change and economical development that happened in West Africa during the XXth century had a lot of consequences on human settlement and landscape. These changes have in turn an impact on the pathogenic system of human and animal trypanosomoses. Since last century, the northern tsetse distribution limit has shifted towards the south, probably due to a decrease in rainfall combined to the impact of human pressure. Sleeping sickness (SS) foci have also shifted from the savannah areas (where there is no more SS) to the forest and mangrove areas of West Africa, but animal trypanosomoses are still present in savannah. We show a decrease of tsetse of the morsitans group as a result of an increase of human densities. On the opposite, tsetse species like Glossina palpalis adapt to high human densities and are found in the biggest urban centres of West Africa. There is a need to promote multidisciplinary studies on this demographic-climatic-vector borne disease topic, especially in Africa to be able to define future areas of presence/absence of these diseases in order to help continental plans of control that have recently begun.

  16. Building Sustainable Local Capacity for Global Health Research in West Africa.

    PubMed

    Sam-Agudu, Nadia A; Paintsil, Elijah; Aliyu, Muktar H; Kwara, Awewura; Ogunsola, Folasade; Afrane, Yaw A; Onoka, Chima; Awandare, Gordon A; Amponsah, Gladys; Cornelius, Llewellyn J; Mendy, Gabou; Sturke, Rachel; Ghansah, Anita; Siberry, George K; Ezeanolue, Echezona E

    Global health research in resource-limited countries has been largely sponsored and led by foreign institutions. Thus, these countries' training capacity and productivity in global health research is limited. Local participation at all levels of global health knowledge generation promotes equitable access to evidence-based solutions. Additionally, leadership inclusive of competent local professionals promotes best outcomes for local contextualization and implementation of successful global health solutions. Among the sub-Saharan African regions, West Africa in particular lags in research infrastructure, productivity, and impact in global health research. In this paper, experts discuss strategies for scaling up West Africa's participation in global health evidence generation using examples from Ghana and Nigeria. We conducted an online and professional network search to identify grants awarded for global health research and research education in Ghana and Nigeria. Principal investigators, global health educators, and representatives of funding institutions were invited to add their knowledge and expertise with regard to strengthening research capacity in West Africa. While there has been some progress in obtaining foreign funding, foreign institutions still dominate local research. Local research funding opportunities in the 2 countries were found to be insufficient, disjointed, poorly sustained, and inadequately publicized, indicating weak infrastructure. As a result, research training programs produce graduates who ultimately fail to launch independent investigator careers because of lack of mentoring and poor infrastructural support. Research funding and training opportunities in Ghana and Nigeria remain inadequate. We recommend systems-level changes in mentoring, collaboration, and funding to drive the global health research agenda in these countries. Additionally, research training programs should be evaluated not only by numbers of individuals graduated but

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

    NASA Astrophysics Data System (ADS)

    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.

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

    NASA Astrophysics Data System (ADS)

    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. First highlights of the Dynamics-Aerosol-Chemistry-Cloud Interactions in West Africa (DACCIWA) field campaigns

    NASA Astrophysics Data System (ADS)

    Liousse, C.; Knippertz, P.; Flamant, C.; Adon, J.; Akpo, A.; Annesi-Maesano, I.; Assamoi, E.; Baeza, A.; Julien, B.; Bedou, M.; Brooks, B. J.; Chiu, J. Y. C.; Chiron, C.; Coe, H.; Danuor, S.; Djossou, J.; Evans, M. J.; Fayomi, B.; Fink, A. H.; Galy-Lacaux, C.; Gardrat, E.; Jegede, O.; Kalthoff, N.; Kedote, M.; Keita, S.; Kouame, K.; Konare, A.; Leon, J. F.; Mari, C. H.; Lohou, F.; Roblou, L.; Schlager, H.; Schwarzenboeck, A.; Toure, E. N.; Veronique, Y.

    2016-12-01

    The EU-funded project DACCIWA (Dynamics-Aerosol-Chemistry-Cloud Interactions in West Africa) is investigating the relationship between weather, climate, air pollution and health in southern West Africa. The air over the coastal region of West Africa is a unique mixture of natural and anthropogenic gases, liquids and particles, emitted in an environment, in which multi-layer cloud decks frequently form. These exert a large influence on the local weather and climate, which has never been studied in detail over West Africa: this information is currently not included in the majority of weather and climate models. For the first time, the entire chain of impacts of natural and manmade emissions on the West African atmosphere was investigated in a coordinated field campaign. As part of this campaign, three research aircraft (Falcon 20, Twin Otter and ATR) based in Lomé (Togo) flew targeted 50 missions over West Africa from 27 June to 16 July 2016. In that campaign also, three highly instrumented measuring sites inland were set up with weather balloons launched several times a day across the region. The main objective was to build robust statistics of cloud properties in southern West Africa in different chemical landscapes (background state, ship/flaring emissions, polluted megacities, agricultural and forest areas, dust from the Sahel/Sahara). In addition, DACCIWA scientists working on measurements of urban emissions, air pollution, and health have set up four urban sites in Abidjan (Cote d'Ivoire) and Cotonou (Benin) focusing on main specific regional combustion sources (domestic fires, traffic and waste burning). Long-term measurements of gases and particles and census of hospital admissions for respiratory diseases were started in January 2015 and will continue until March 2017 to determine the links between human health and air pollution. Intensive measurement periods took place in July 2015, January 2016, and July 2016 (a final one is planned for January 2017) in

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

    NASA Astrophysics Data System (ADS)

    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

  1. Onchocerciasis: a major social problem in West Africa.

    PubMed

    Quarcoopome, C O

    1983-01-01

    Onchocerciasis is one of the most serious blinding diseases in the world, affecting between 20 and 25 million people, of whom 200-500 thousand are blind. In Africa more than half of the countries on the continent are affected, the basin of the Volta river containing one of the largest endemic areas. In this area the unique Onchocerciasis Control Program (OCP) is being undertaken, involving Benin, Ghana, Ivory Coast, Mali, Niger, Togo and Upper Volta. In this region, surveys have shown that 14.78% of the population have microfilariae in their skin biopsies, while in hyperendemic villages the figure rises to 75.2%. In such a village the prevalence of blindness rises steeply with age, from 0% under age 20, to over 40% in the over 50 age group. Various environmental factors relevant to the prevalence and incidence of systemic and ocular onchocerciasis are discussed, and pharmacologic treatment modalities are described. Prevention activities, centred around vector control by insecticides, have been dramatically effective.

  2. Atmospheric nutrient deposition to the west coast of South Africa

    NASA Astrophysics Data System (ADS)

    Nyaga, Justine M.; Cramer, Michael D.; Neff, Jason C.

    2013-12-01

    Atmospheric deposition is an important source of nutrients to many ecosystems, but is of particular importance to plant nutrition in areas where nutrients are scarce. Nutrient containing aerosols enter the atmosphere through industrial and agricultural activities, wildfires, and the production of terrigenous and marine aerosols. In this study, we collected bulk rain precipitation along the Atlantic coast of South Africa in a coastal “strandveld” vegetation region. This region is relatively remote from significant anthropogenic influences and is downwind of a highly productive and stormy portion of the Atlantic. Samples were collected over 12 months at sites along a 17 km downwind transect from the shoreline and analyzed for N, P, Na, Ca, Mg and K. Annual total N and total P fluxes of 4.8 kg ha-1 yr-1 and 0.16 kg ha-1 yr-1 are low compared to global averages. In contrast, fluxes of Na were 88.7 kg ha-1 yr-1, 16.2 kg ha-1 yr-1 for Ca, 12.1 kg ha-1 yr-1 for Mg and 5.2 kg ha-1 yr-1 for K; rates that are higher than most other measurements elsewhere in the world. Dissolved organic N represented ca. 71% of the N flux while 43% of the P flux was in the form of soluble reactive P (SRP). These results combined with the high fluxes of Na and Mg strongly suggest that marine aerosols are important contributors to nutrient deposition at this site.

  3. [Ministerial Conference on Migration and Urbanization in West Africa: declaration].

    PubMed

    1999-12-01

    This declaration made by the participants of the Ministerial Conference on Migration and Urbanization in Western Africa, held in Bamako during November 5, 1999, commits the countries of the region to do the following: follow the urbanization process in an effort to make African cities hubs of development and social progress; improve the geographic distribution of populations; bring economic development to mid-sized cities; implement rural development projects and programs, especially in the least advantaged zones; manage urban constraints; define new pathways and coordinated approaches; implement measures which account for those who are newly migrating, such as women and young people; minimize administrative hurdles associated with the return and reintegration of migrants; provide those bodies responsible for urbanization and migration concerns with the communication tools they require; take the necessary measures to facilitate migrants¿ stays and inform potential migrants about the conditions of such stay in host countries; adapt laws to conform with the charters of subregional organizations; consider migration concerns at the commission level; and implement clear, explicit migration policies. Recommendations are offered to the Permanent Interstate Committee Against Drought in the Sahel (CILSS) as well as to all subregional organizations. It is hoped that international organizations and partner agencies in development will support countries¿ efforts.

  4. [Malaria prophylaxis of West German travelers to Africa].

    PubMed

    Steffen, R; Mächler, R; Heusser, R; Naef, U

    1990-02-23

    From May 1985 to July 1988, 11,445 German residents who had travelled to Africa filled in a questionnaire during the return flight and a second questionnaire sent to them 3 months later. 92.6% of the travellers had been on holiday and 99.3% of these holiday-makers were aware of the risk of malaria. Before and during their stay in the tropics 10,955 travellers (95.7%) had taken the chemoprophylaxis correctly, though in some instances the drugs prescribed were not in accordance with the guidelines existing at the time. However, 3227 of them (35.5%) discontinued the drugs too early, i.e. less than four weeks after their return. Only 4.3% of the travellers had taken proper precautions against mosquito bites. In view of the ever increasing numbers of people travelling to countries where malaria is endemic, doctors and travelers should be provided with more information and should be given more consistent advice on malaria prophylaxis.

  5. Geology of the Douala basin, offshore Cameroon, West Africa

    SciTech Connect

    Pauken, R.J.; Thompson, J.M.; Schumann, J.R. ); Cooke, J.C. )

    1991-03-01

    The Douala basin is predominantly an offshore basin extending from the Cameroon volcanic line in the north to the Corisco arch in the south near the Equatorial Guinea-Gabon border. The basin lies wholly within the territorial borders of Cameroon and Equatorial Guinea. The Douala basin is one of a series of divergent margin basins occurring along the southwest African coastline resulting from the rifting of Africa from South America. Continental rifting in the Doula basin was initiated at least by Aptian-Albian time and possibly as early as Jurassic. The rift stage persisted until Albian time when the onset of drifting occurred. The sedimentary section in the basin has a maximum thickness of 8-10 km, based on exploration drilling and gravity and magnetics modeling. The synrift section consists of Aptian-Albian sands and shales, deposited primarily as submarine fans, fan-deltas, and turbidite deposits. These are overlain by salt, thought to be equivalent to the Ezagna salt of Aptian age in the Gabon basin to the south. The synrift section is separated from the overlying postrift shale sequence of Late Cretaceous and Tertiary age by a major late Albian unconformity. The Douala basin has been explored for hydrocarbons intermittently over the last 25 years. Results show a distinct tendency for gas-proneness. The largest field recorded to date is the Sanaga Sud gas field, discovered in 1979, offshore, near the coastal city of Kribi.

  6. Meteorological causes of Harmattan dust in West Africa

    NASA Astrophysics Data System (ADS)

    Schwanghart, Wolfgang; Schütt, Brigitta

    2008-03-01

    We investigated the temporal dynamics of dust entrainment in the Bodélé Depression, Central Sahara, to better understand the intra-annual variability of aerosol emission in the world's largest dust source. The linkages between dust entrainment and large-scale meteorological factors were examined by correlating several meteorological variables in the Mediterranean and Africa north of the equator with the aerosol concentrations in the Bodélé Depression separately for winter and summer. The methodological tools applied are NCEP/NCAR reanalysis data and the aerosol index of the Total Ozone Mapping Spectrometer (TOMS-AI), available for 15 years from 1978 to 1993. We found that dust mobilisation during the Harmattan season is highly dependent on air pressure variability in the Mediterranean area. High pressure to the north of the Bodélé intensifies the NE trade winds, leading to an increased entrainment of dust in the Bodélé Depression. In summer, dust mobilization cannot be explained by the large scale meteorological conditions. This highlights the importance of local to regional wind systems linked to the northernmost position of the intertropical convection zone (ITCZ) during this time.

  7. Southern Africa

    Atmospheric Science Data Center

    2013-04-16

    ... tip of South Africa is at the bottom of the image, and Zambia is at the top. Distinctive features about a third of the way from the ... MISR Team. Aug 25, 2000 - South Africa to Zambia including the Okavango Delta. project:  MISR ...

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

    PubMed Central

    Maca-Meyer, Nicole; González, Ana M; Pestano, José; Flores, Carlos; Larruga, José M; Cabrera, Vicente M

    2003-01-01

    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. PMID:14563219

  9. Geology and total petroleum systems of the West-Central Coastal province (7203), West Africa

    USGS Publications Warehouse

    Brownfield, Michael E.; Charpentier, Ronald R.

    2006-01-01

    The West-Central Coastal Province of the Sub-Saharan Africa Region consists of the coastal and offshore areas of Cameroon, Equatorial Guinea, Gabon, Democratic Republic of the Congo, Republic of the Congo, Angola (including the disputed Cabinda Province), and Namibia. The area stretches from the east edge of the Niger Delta south to the Walvis Ridge. The West-Central Coastal Province includes the Douala, Kribi-Campo, Rio Muni, Gabon, Congo, Kwanza, Benguela, and Namibe Basins, which together form the Aptian salt basin of equatorial west Africa. The area has had significant exploration for petroleum; more than 295 oil fields have been discovered since 1954. Since 1995, several giant oil fields have been discovered, especially in the deep-water area of the Congo Basin. Although many total petroleum systems may exist in the West-Central Coastal Province, only four major total petroleum systems have been defined. The area of the province north of the Congo Basin contains two total petroleum systems: the Melania-Gamba Total Petroleum System, consisting of Lower Cretaceous source and reservoir rocks, and the Azile-Senonian Total Petroleum System, consisting of Albian to Turonian source rocks and Cretaceous reservoir rocks. Two assessment units are defined in the West-Central Coastal Province north of the Congo Basin: the Gabon Subsalt and the Gabon Suprasalt Assessment Units. The Congo Basin contains the Congo Delta Composite Total Petroleum System, consisting of Lower Cretaceous to Tertiary source and reservoir rocks. The Central Congo Delta and Carbonate Platform and the Central Congo Turbidites Assessment Units are defined in the Congo Delta Composite Total Petroleum System. The area south of the Congo Basin contains the Cuanza Composite Total Petroleum System, consisting of Lower Cretaceous to Tertiary source and reservoir rocks. The Cuanza-Namibe Assessment Unit is defined in the Cuanza Composite Total Petroleum System. The U.S. Geological Survey (USGS) assessed the

  10. Response of the water cycle of West Africa and Atlantic to radiative forcing by Saharan dust (Invited)

    NASA Astrophysics Data System (ADS)

    Lau, W. K.; Kim, K.

    2010-12-01

    The responses of the atmospheric water cycle and climate of West Africa and the Atlantic toradiative forcing of Saharan dust are studied using the NASA finite volume general circulation model (fvGCM), coupled to a mixed layer ocean. We find evidence in support of the “elevated heat pump” (EHP) mechanism that underlines the responses of the atmospheric water cycle to dust forcing as follow. During the boreal summer, as a result of large-scale atmospheric feedback triggered by absorbing dust aerosols, rainfall and cloudiness are enhanced over the West Africa/Eastern Atlantic ITCZ, and suppressed over the West Atlantic and Caribbean region. Shortwave radiation absorption by dust warms the atmosphere and cools the surface, while longwave has the opposite response. The elevated dust layer warms the air over West Africa and the eastern Atlantic. As the warm air rises, it spawns a large-scale onshore flow carrying the moist air from the eastern Atlantic and the Gulf of Guinea. The onshore flow in turn enhances the deep convection over West Africa land, and the eastern Atlantic. The condensation heating associated with the induced deep convection drives and maintains an anomalous large-scale east-west overturning circulation with rising motion over West Africa/eastern Atlantic, and sinking motion over the Caribbean region. The response also includes a strengthening of the West African monsoon, manifested in a northward shift of the West Africa precipitation over land, increased low-level westerlies flow over West Africa at the southern edge of the dust layer, and a near surface westerly jet underneath the dust layer over the Sahara. The dust radiative forcing also leads to significant changes in surface energy fluxes, resulting in cooling of the West African land and the eastern Atlantic, and warming in the West Atlantic and Caribbean. The EHP effect is most effective for moderate to highly absorbing dusts, and becomes minimized for reflecting dust with single

  11. Precipitation Characteristics in West and East Africa from Satellite and in Situ Observations

    NASA Technical Reports Server (NTRS)

    Dezfuli, Amin K.; Ichoku, Charles M.; Mohr, Karen I.; Huffman, George J.

    2017-01-01

    Using in situ data, three precipitation classes are identified for rainy seasons of West and East Africa: weak convective rainfall (WCR), strong convective rainfall (SCR), and mesoscale convective systems (MCSs).Nearly 75% of the total seasonal precipitation is produced by the SCR and MCSs, even though they represent only 8% of the rain events. Rain events in East Africa tend to have a longer duration and lower intensity than in West Africa, reflecting different characteristics of the SCR and MCS events in these two regions. Surface heating seems to be the primary convection trigger for the SCR, particularly in East Africa, whereas the WCR requires a dynamical trigger such as low-level convergence. The data are used to evaluate the performance of the recently launched Integrated Multi-satellite Retrievals for Global Precipitation Measurement (IMERG)project. The IMERG-based precipitation shows significant improvement over its predecessor, the Tropical Rainfall Measuring Mission (TRMM) Multi-satellite Precipitation Analysis (TMPA), particularly in capturing the MCSs, due to its improved temporal resolution.

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

    NASA Astrophysics Data System (ADS)

    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.

  13. The West Africa Disaster Preparedness Initiative: Strengthening National Capacities for All-Hazards Disaster Preparedness.

    PubMed

    Morton Hamer, Melinda J; Reed, Paul L; Greulich, Jane D; Kelen, Gabor D; Bradstreet, Nicole A; Beadling, Charles W

    2017-08-01

    The Ebola outbreak demonstrated the need for improved disaster response throughout West Africa. The West Africa Disaster Preparedness Initiative was a training and assessment effort led by US Africa Command and partners to strengthen capacities among 12 West African partner nations (PNs). Series of 3-week training sessions with representatives from each PN were held from 13 July through 20 November 2015 at the Kofi Annan International Peacekeeping Training Centre in Accra, Ghana. A team conducted Disaster Management Capabilities Assessments (DMCAs) for each PN, including a review of key data, a survey for leaders, and in-person interviews of key informants. All 12 PNs generated a national Ebola Preparedness and Response Plan and Emergency Operations Center standard operating procedures. DMCA metrics were generated for each PN. Top performers included Ghana, with a plan rated good/excellent, and Benin and Burkina Faso, which both achieved a satisfactory rating for their plans. More than 800 people from 12 nations were trained. PNs have improved disaster management capabilities and awareness of their strengths and weaknesses. The Economic Community of West African States has increased its lead role in this and future planned initiatives. (Disaster Med Public Health Preparedness. 2017;11:431-438).

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

    NASA Astrophysics Data System (ADS)

    Diasso, Ulrich; Abiodun, Babatunde J.

    2017-04-01

    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.

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

    NASA Astrophysics Data System (ADS)

    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.

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

    NASA Astrophysics Data System (ADS)

    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

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

    NASA Astrophysics Data System (ADS)

    Capes, G.; Murphy, J. G.; Reeves, C. E.; McQuaid, J. B.; Hamilton, J. F.; Hopkins, J. R.; Crosier, J.; Williams, P. I.; Coe, H.

    2009-01-01

    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.

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

    NASA Astrophysics Data System (ADS)

    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.

  19. Non-biomedical factors in the Ebola virus disease outbreak in West Africa.

    PubMed

    Adachi, Takuya

    2015-01-01

    The outbreak of Ebola virus disease, reported in West Africa in 2014, has become the largest ever one in the history. Tremendous efforts by all the parties concerned are now bringing this epidemic closer to the end, while observing a large number of cases and deaths, including health care workers.This paper features five questions:1. Why did it emerge in West Africa?2. Why has it spread so wide and intensely?3. Why were so many health care workers infected?4. Why is it being brought under control?5. Would it emerge and spread in Japan in the same way?Ebola virus transmits through human acts such as caregiving of the sick and attending a funeral, therefore an epidemic is not likely to subside naturally, but intentional interventions are needed to terminate its transmission. Who the outbreak response is meant for, either patients, the general public in the affected countries, or international communities, also determines its success or failure.

  20. What aspects of future rainfall changes matter for crop yields in West Africa?

    NASA Astrophysics Data System (ADS)

    Guan, Kaiyu; Sultan, Benjamin; Biasutti, Michela; Baron, Christian; Lobell, David B.

    2015-10-01

    How rainfall arrives, in terms of its frequency, intensity, the timing and duration of rainy season, may have a large influence on rainfed agriculture. However, a thorough assessment of these effects is largely missing. This study combines a new synthetic rainfall model and two independently validated crop models (APSIM and SARRA-H) to assess sorghum yield response to possible shifts in seasonal rainfall characteristics in West Africa. We find that shifts in total rainfall amount primarily drive the rainfall-related crop yield change, with less relevance to intraseasonal rainfall features. However, dry regions (total annual rainfall below 500 mm/yr) have a high sensitivity to rainfall frequency and intensity, and more intense rainfall events have greater benefits for crop yield than more frequent rainfall. Delayed monsoon onset may negatively impact yields. Our study implies that future changes in seasonal rainfall characteristics should be considered in designing specific crop adaptations in West Africa.

  1. Predicted impacts of climate change on malaria transmission in West Africa

    NASA Astrophysics Data System (ADS)

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

    2014-12-01

    Increases in temperature and changes in precipitation due to climate change are expected to alter the spatial distribution of malaria transmission. This is especially true in West Africa, where malaria prevalence follows the current north-south gradients in temperature and precipitation. We assess the skill of GCMs at simulating past and present climate in West Africa in order to select the most credible climate predictions for the periods 2030-2060 and 2070-2100. We then use the Hydrology, Entomology and Malaria Transmission Simulator (HYDREMATS), a mechanistic model of malaria transmission, to translate the predicted changes in climate into predicted changes availability of mosquito breeding sites, mosquito populations, and malaria prevalence. We investigate the role of acquired immunity in determining a population's response to changes in exposure to the malaria parasite.

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

    DTIC Science & Technology

    2015-11-01

    Katiri November 2015 The views expressed in this report are those of the author and do not necessarily reflect the official policy or position of the...www.StrategicStudiesInstitute.army.mil/newsletter. ISBN 1-58487-711-1 vii FOREWORD Morocco is seeking to position itself as a regional security provider in West Africa. Over recent...undertaken in recent years extends to security relations, with Morocco seeking to position itself as a regional security provider. Morocco’s renewed

  3. Aircraft-based investigation of Dynamics-Aerosol-Chemistry-Cloud Interactions in Southern West Africa

    NASA Astrophysics Data System (ADS)

    Flamant, Cyrille

    2017-04-01

    The EU-funded project DACCIWA (Dynamics-Aerosol-Chemistry-Cloud Interactions in West Africa, http://www.dacciwa.eu) is investigating the relationship between weather, climate and air pollution in southern West Africa. The air over the coastal region of West Africa is a unique mixture of natural and anthropogenic gases, liquids and particles, emitted in an environment, in which multi-layer cloud decks frequently form. These exert a large influence on the local weather and climate, mainly due to their impact on radiation, the surface energy balance and thus the diurnal cycle of the atmospheric boundary layer. The main objective for the aircraft detachment was to build robust statistics of cloud properties in southern West Africa in different chemical landscapes to investigate the physical processes involved in their life cycle in such a complex chemical environment. As part of the DACCIWA field campaigns, three European aircraft (the German DLR Falcon 20, the French SAFIRE ATR 42 and the British BAS Twin Otter) conducted a total of 50 research flights across Ivory Coast, Ghana, Togo, and Benin from 27 June to 16 July 2016 for a total of 155 flight hours, including hours sponsored through 3 EUFAR projects. The aircraft were used in different ways based on their strengths, but all three had comparable instrumentation with the the capability to do gas-phase chemistry, aerosol and clouds, thereby generating a rich dataset of atmospheric conditions across the region. Eight types of flight objectives were conducted to achieve the goals of the DACCIWA: (i) Stratus clouds, (ii) Land-sea breeze clouds, (iii) Mid-level clouds, (iv) Biogenic emission, (v) City emissions, (vi) Flaring and ship emissions, (vii) Dust and biomass burning aerosols, and (viii) air-sea interactions. An overview of the DACCIWA aircraft campaign as well as first highlights from the airborne observations will be presented.

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

    NASA Technical Reports Server (NTRS)

    Jemison, Mae C.; Thomas, J. Segun

    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 provide timely epidemiologic information, sharing of medical expertise through telemedical consultations, enhance optimized resource distribution and build a framework for telecommunications for the entire country.

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

    NASA Technical Reports Server (NTRS)

    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.

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

    NASA Technical Reports Server (NTRS)

    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.

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

    NASA Technical Reports Server (NTRS)

    Jemison, Mae C.; Thomas, J. Segun

    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 provide timely epidemiologic information, sharing of medical expertise through telemedical consultations, enhance optimized resource distribution and build a framework for telecommunications for the entire country.

  8. Assessment of Undiscovered Oil and Gas Resources of Four West Africa Geologic Provinces

    USGS Publications Warehouse

    Brownfield, Michael E.; Charpentier, Ronald R.; Cook, Troy A.; Klett, Timothy R.; Pitman, Janet K.; Pollastro, Richard M.; Schenk, Christopher J.; Tennyson, Marilyn E.

    2010-01-01

    Four geologic provinces located along the northwest and west-central coast of Africa recently were assessed for undiscovered oil, natural gas, and natural gas liquids resources as part of the U.S. Geological Survey's (USGS) World Oil and Gas Assessment. Using a geology-based assessment methodology, the USGS estimated mean volumes of 71.7 billion barrels of oil, 187.2 trillion cubic feet of natural gas, and 10.9 billion barrels of natural gas liquids.

  9. Blood and serum protein groups of the dama of South-West Africa.

    PubMed

    Knussmann, R; Knussmann, R

    1976-01-01

    The phenotype and gene frequencies of the following polymorphisms are given for the blood samples taken from 448 adults of the South-West African Dama Negro tribe: ABO (with sub-groups), MN, Rh, K, Hp, Gc, Gm(1,2,b), InV(1). The frequencies are discussed in comparison with other African samples and a multivariate comparison between series from south-western Africa is conducted. The Dama prove to be relatively independent.

  10. Lower Palaeozoic of North-Western and West-Central Africa

    SciTech Connect

    Holland, C.H.

    1985-01-01

    The first compilation in English of the stratigraphy, palaeontology, sedimentology, palaeogeography, and palaeoclimatology of the Lower Palaeozoic found in this area. The fourth volume in the Lower Palaeozoic Rocks of the World Series discusses geological formations such as the lower Cambrian tribolite-bearing sequences of Morocco, those showing evidence of late Ordovician glaciation in West-Central Africa, and the Silurian-Devonian sequences of Morocco and Algeria.

  11. Secondary Organic Aerosol from Biogenic VOCs over West Africa during AMMA

    NASA Astrophysics Data System (ADS)

    Capes, G. L.; Murphy, J. G.; Reeves, C. E.; McQuaid, J. B.; Hamilton, J. F.; Hopkins, J. R.; Coe, H.

    2008-12-01

    As part of the international AMMA (African Monsoon Multidisciplinary Analyses) project a large field experiment took place in West Africa during July and August 2006. This involved a number of ground-based facilities and 5 aircraft, including the UK Facility for Airborne Atmospheric Measurements (FAAM) BAe-146, which was based in Niamey, Niger and made 21 flights. The 146 was equipped with instruments measuring parameters relevant to dynamics, gas phase composition, radiation, aerosols and clouds. The flights made were designed to examine a range of multidisciplinary scientific questions. This paper presents measurements of organic aerosol above subtropical West Africa during the monsoon season using data from the FAAM aircraft. Measurements of biogenic volatile organic compounds (BVOC) at low altitudes over these subtropical forests were made during July and August 2006 mainly above Benin, Nigeria and Niger. In air masses characterised by high BVOC concentrations, data from an Aerodyne Quadrupole Aerosol Mass Spectrometer show an organic aerosol loading of 0.58 μgm-3 over tropical West Africa. In contrast, organic aerosol mass (OM) concentrations were negligible when BVOC concentrations were low. This represents the first regionally averaged assessment of 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.

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

    PubMed

    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).

  13. The British and curriculum development in West Africa: A historical discourse

    NASA Astrophysics Data System (ADS)

    Ofori-Attah, Kwabena Dei

    2006-09-01

    THE BRITISH AND CURRICULUM DEVELOPMENT IN WEST AFRICA: A HISTORICAL STUDY - Only recently have African nations begun to make their way towards establishing genuinely autonomous education systems incorporating elements of indigenous culture. The present study examines the historical development of curriculum in British West Africa in its links with the educational activities of the early Christian missionaries and the imposition of British colonial rule. For over 300 years, the curriculum content was essentially European in nature. African interests and cultural practices were largely excluded, as "bookwork" was favored over "handwork". The colonial curriculum also helped introduce a new social order to West Africa, leading to the rise of new local elites reading, writing, and speaking foreign European languages. This study explores how the idea of a "civilized" person, promoted through the colonial school curriculum, developed new local elites with different sets of values and expectations that often made them strangers in their own societies. It also describes the connection between this curriculum and the repeated failure of education-reform efforts.

  14. Climate change mitigation by carbon stock - the case of semi-arid West Africa

    NASA Astrophysics Data System (ADS)

    Lykke, A. M.; Barfod, A. S.; Tinggaard Svendsen, G.; Greve, M.; Svenning, J.-C.

    2009-11-01

    Semi-arid West Africa has not been integrated into the afforestation/reforestation (AR) carbon market. Most projects implemented under the Clean Development Mechanism (CDM) have focused on carbon emission reductions from industry and energy consumption, whereas only few (only one in West Africa) have been certified for AR carbon sequestration. A proposed mechanism, Reducing Emissions from Deforestation and Degradation (REDD) to be discussed under COP15 aims to reduce emissions by conserving already existing forests. REDD has high potential for carbon stocking at low costs, but focuses primarily on rain forest countries and excludes semi-arid West Africa from the preliminary setup. African savannas have potential to store carbon in the present situation with degrading ecosystems and relatively low revenues from crops and cattle, especially if it is possible to combine carbon stocking with promotion of secondary crops such as food resources and traditional medicines harvested on a sustainable basis. Methods for modelling and mapping of potential carbon biomass are being developed, but are still in a preliminary state. Although economic benefits from the sale of carbon credits are likely to be limited, carbon stocking is an interesting option if additional benefits are considered such as improved food security and protection of biodiversity.

  15. Biological and Phylogenetic Characteristics of Yellow Fever Virus Lineages from West Africa

    PubMed Central

    Laraway, Hewád; Faye, Ousmane; Diallo, Mawlouth; Niedrig, Matthias

    2013-01-01

    The yellow fever virus (YFV), the first proven human-pathogenic virus, although isolated in 1927, is still a major public health problem, especially in West Africa where it causes outbreaks every year. Nevertheless, little is known about its genetic diversity and evolutionary dynamics, mainly due to a limited number of genomic sequences from wild virus isolates. In this study, we analyzed the phylogenetic relationships of 24 full-length genomes from YFV strains isolated between 1973 and 2005 in a sylvatic context of West Africa, including 14 isolates that had previously not been sequenced. By this, we confirmed genetic variability within one genotype by the identification of various YF lineages circulating in West Africa. Further analyses of the biological properties of these lineages revealed differential growth behavior in human liver and insect cells, correlating with the source of isolation and suggesting host adaptation. For one lineage, repeatedly isolated in a context of vertical transmission, specific characteristics in the growth behavior and unique mutations of the viral genome were observed and deserve further investigation to gain insight into mechanisms involved in YFV emergence and maintenance in nature. PMID:23269797

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

    PubMed

    Dean, Anna S; Fournié, Guillaume; Kulo, Abalo E; Boukaya, G Aboudou; Schelling, Esther; Bonfoh, Bassirou

    2013-01-01

    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. 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. 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.

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

    NASA Astrophysics Data System (ADS)

    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

  18. Crop planting date optimization: An approach for climate change adaptation in West Africa

    NASA Astrophysics Data System (ADS)

    Waongo, Moussa; Laux, Patrick; Kunstmann, Harald

    2014-05-01

    Agriculture is the main source of income for population and the main driver of economy in Africa, particularly in West Africa. West African agriculture is dominated by rainfed agriculture. This agricultural system is characterized by smallholder and subsistence farming, and a limited use of crop production inputs such as machines, fertilizers and pesticides. Therefore, crop yield is strongly influenced by climate fluctuation and is more vulnerable to climate change and climate variability. To reduce climate risk on crop production, a development of tailored agricultural management strategies is required. The usage of agricultural management strategies such as tailored crop planting date might contribute both to reduce crop failure and to increased crop production. In addition, unlike aforementioned crop production inputs, the usage of tailored planting dates is costless for farmers. Thus, efforts to improve crop production by optimizing crop planting date can contribute to alleviate food insecurity in West Africa, in the context of climate change. In this study, the process-based crop model GLAM (General Large Area Model for annual crop) in combination with a fuzzy logic approach for planting date have been coupled with a genetic algorithm to derive Optimized Planting Dates (OPDs) for maize cropping in Burkina Faso, West Africa. For a specific location, the derived OPDs correspond to a time window for crop planting. To analyze the performance of the OPDs approach, the derived OPDs has been compared to two well-known planting date methods in West Africa. The results showed a mean OPD ranging from May 1st (South-West) to July 11th (North) across the country. In comparison with well-known methods, the OPD approach yielded earliest planting dates across Burkina Faso. The deviation of OPDs from planting dates derived from the well known methods ranged from 10 days to 20 days for the northern and central region, and less than 10 days for the southern region. With respect

  19. Evaluation of high-resolution climate simulations for West Africa using COSMO-CLM

    NASA Astrophysics Data System (ADS)

    Dieng, Diarra; Smiatek, Gerhard; Bliefernicht, Jan; Laux, Patrick; Heinzeller, Dominikus; Kunstmann, Harald; Sarr, Abdoulaye; Thierno Gaye, Amadou

    2017-04-01

    The climate change modeling activities within the WASCAL program (West African Science Service Center on Climate Change and Adapted Land Use) concentrate on the provisioning of future climate change scenario data at high spatial and temporal resolution and quality in West Africa. Such information is highly required for impact studies in water resources and agriculture for the development of reliable climate change adaptation and mitigation strategies. In this study, we present a detailed evaluation of high simulation runs based on the regional climate model, COSMO model in CLimate Mode (COSMO-CLM). The model is applied over West Africa in a nested approach with two simulation domains at 0.44° and 0.11° resolution using reanalysis data from ERA-Interim (1979-2013). The models runs are compared to several state-of-the-art observational references (e.g., CRU, CHIRPS) including daily precipitation data provided by national meteorological services in West Africa. Special attention is paid to the reproduction of the dynamics of the West African Monsoon (WMA), its associated precipitation patterns and crucial agro-climatological indices such as the onset of the rainy season. In addition, first outcomes of the regional climate change simulations driven by MPI-ESM-LR are presented for a historical period (1980 to 2010) and two future periods (2020 to 2050, 2070 to 2100). The evaluation of the reanalysis runs shows that COSMO-CLM is able to reproduce the observed major climate characteristics including the West African Monsoon within the range of comparable RCM evaluations studies. However, substantial uncertainties remain, especially in the Sahel zone. The added value of the higher resolution of the nested run is reflected in a smaller bias in extreme precipitation statistics with respect to the reference data.

  20. Family Planning Programmes in Africa.

    ERIC Educational Resources Information Center

    Pradervand, Pierre

    The countries discussed in this paper are the francophone countries of West Africa and the Republic of Congo, with comparative references made to North Africa (mainly Morocco, Algeria, and Tunisia). Obstacles to the adoption of family planning in the countries of tropical Africa are a very high mortality rate among children; a socioeconomic…

  1. Tracer redistribution by clouds in West Africa: Numerical modeling for dry and wet seasons

    SciTech Connect

    Renard, M.; Chaumerliac, N.; Cautenet, S.; Nickerson, E.C. |

    1994-06-01

    The vertical transport by clouds of an inert tracer and its redistribution by complex West African circulations are examined using a two-dimensional mesoscale meteorological model with explicit microphysics. The model reproduces the tropical distribution of clouds and precipitation along a meridional cross section over West Africa, corresponding to the position of the Intertropical Convergence Zone (ITCZ) during the dry and rainy seasons. The resulting redistribution of the inert tracer is therefore closely related to the northward migration of the ITCZ between January and July. The occurrence of biomass burning during the dry season is shown to be an important source of tracer enrichment at upper levels in the atmosphere.

  2. A revised picture of the structure of the ``monsoon'' and land ITCZ over West Africa

    NASA Astrophysics Data System (ADS)

    Nicholson, Sharon E.

    2009-06-01

    This article presents an overview of the land ITCZ (Intertropical Convergence Zone) over West Africa, based on analysis of NCAR-NCEP Reanalysis data. The picture that emerges is much different than the classic one. The most important feature is that the ITCZ is effectively independent of the system that produces most of the rainfall. Rainfall linked directly to this zone of surface convergence generally affects only the southern Sahara and the northern-most Sahel, and only in abnormally wet years in the region. A second feature is that the rainbelt normally assumed to represent the ITCZ is instead produced by a large core of ascent lying between the African Easterly Jet and the Tropical Easterly Jet. This region corresponds to the southern track of African Easterly Waves, which distribute the rainfall. This finding underscores the need to distinguish between the ITCZ and the feature better termed the “tropical rainbelt”. The latter is conventionally but improperly used in remote sensing studies to denote the surface ITCZ over West Africa. The new picture also suggests that the moisture available for convection is strongly coupled to the strength of the uplift, which in turn is controlled by the characteristics of the African Easterly Jet and Tropical Easterly Jet, rather than by moisture convergence. This new picture also includes a circulation feature not generally considered in most analyses of the region. This feature, a low-level westerly jet termed the African Westerly Jet, plays a significant role in interannual and multidecadal variability in the Sahel region of West Africa. Included are discussions of the how this new view relates to other aspects of West Africa meteorology, such as moisture sources, rainfall production and forecasting, desertification, climate monitoring, hurricanes and interannual variability. The West African monsoon is also related to a new paradigm for examining the interannual variability of rainfall over West Africa, one that

  3. A-level Biology in West Africa: A New Syllabus

    ERIC Educational Resources Information Center

    Ewer, D. W.

    1969-01-01

    Describes a biology course developed for West African senior high school students. Ecology is used as an integrating theme, and the approach is problem centered. Discusses the proposed form of examinations in the course. (EB)

  4. Air pollution in Southern West Africa: Impact of different emission inventories

    NASA Astrophysics Data System (ADS)

    Stanelle, Tanja; Lohmann, Ulrike; Neubauer, David; Bey, Isabelle

    2017-04-01

    Southern West Africa is currently experiencing an unprecedented population growth of 2-3 % per year and an economic growth of approximately 5% per year. This has an impact on land use change and anthropogenic emissions (United Nations Economic Commission for Africa, 2010), which can result in modifications of aerosol concentrations. Aerosols modify the climate by scattering and absorption of radiation and by acting as cloud condensation and ice nuclei. The quality of emission inventories is crucial for simulating anthropogenic aerosol concentrations. But for West Africa it turns out that the estimated emission fluxes differ between inventories (e.g. ACCMIP, EDGAR). With our global aerosol-climate model ECHAM6-HAM2 we investigate the feedbacks between aerosol emissions (natural and anthropogenic), aerosol distributions and climate. We performed a set of simulations with ECHAM6-HAM2 with use of different emission inventories for present day conditions. We show the differences in aerosol distributions depending on the applied inventory. Further we discuss the consequences of these differences on the projected climate impact of aerosols.

  5. Polyglots, Vernaculars and Global Markets: Variable Trends in West Africa

    ERIC Educational Resources Information Center

    Adejunmobi, Moradewun

    2004-01-01

    Using a framework from cultural studies and focusing on theories put forward by Pierre Bourdieu, the goal in this paper is to consider how some West Africans interact with foreign languages and cultures in an era of global capital, especially when it comes to the activities of migrants venturing into overseas labour markets and to the production…

  6. Polyglots, Vernaculars and Global Markets: Variable Trends in West Africa

    ERIC Educational Resources Information Center

    Adejunmobi, Moradewun

    2004-01-01

    Using a framework from cultural studies and focusing on theories put forward by Pierre Bourdieu, the goal in this paper is to consider how some West Africans interact with foreign languages and cultures in an era of global capital, especially when it comes to the activities of migrants venturing into overseas labour markets and to the production…

  7. Development of a regional food composition table for West Africa.

    PubMed

    Stadlmayr, Barbara; Charrondière, U Ruth; Burlingame, Barbara

    2013-10-01

    Knowledge of the nutrient content of foods is fundamental for virtually all nutrition-related projects, programmes and policies. Low quality compositional data may lead to inappropriate policies and funds spent unnecessarily. Existing food composition tables (FCT) for most West African countries date back to 1960 and 1970 and contain in general few foods and components without documentation. As a result of the recommendations by the Economic Community of West African States (ECOWAS) Nutrition forum and other high level meetings, FAO/INFOODS, WAHO/ECOWAS and Bioversity International developed the West African FCT. It contains 472 foods and 28 components. Emphasis was given to include data on food biodiversity by incorporating cultivars/varieties and underutilized foods. The West African FCT enables users to address diet-related health problems, strengthen local development, enhance trade and promote biodiversity. In addition it contributes to poverty alleviation in both rural and urban areas. The FCT needs to be updated regularly and it is the most recent example of INFOODS for regional food composition activities. Copyright © 2012 The Food and Agriculture Organization of the United Nations (FAO). Published by Elsevier Ltd.. All rights reserved.

  8. Missionary Education in West Africa: A Study of Pedagogical Ambition

    ERIC Educational Resources Information Center

    Ustorf, Werner

    2011-01-01

    The history of the North German Mission Society (established 1836 in Hamburg) and its activity on the West African coast (from 1847 onwards among the Ewe, in what is now Ghana and Togo where it was and still is known as the "Bremen Mission") mirrors neatly the various phases of the idea of "mission": its composite motivation…

  9. Virtual Reference Service in Academic Libraries in West Africa

    ERIC Educational Resources Information Center

    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…

  10. Missionary Education in West Africa: A Study of Pedagogical Ambition

    ERIC Educational Resources Information Center

    Ustorf, Werner

    2011-01-01

    The history of the North German Mission Society (established 1836 in Hamburg) and its activity on the West African coast (from 1847 onwards among the Ewe, in what is now Ghana and Togo where it was and still is known as the "Bremen Mission") mirrors neatly the various phases of the idea of "mission": its composite motivation…

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

    PubMed

    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.

  12. Spatiotemporal Analysis of the Ebola Hemorrhagic Fever in West Africa in 2014

    NASA Astrophysics Data System (ADS)

    Xu, M.; Cao, C. X.; Guo, H. F.

    2017-09-01

    Ebola hemorrhagic fever (EHF) is an acute hemorrhagic diseases caused by the Ebola virus, which is highly contagious. This paper aimed to explore the possible gathering area of EHF cases in West Africa in 2014, and identify endemic areas and their tendency by means of time-space analysis. We mapped distribution of EHF incidences and explored statistically significant space, time and space-time disease clusters. We utilized hotspot analysis to find the spatial clustering pattern on the basis of the actual outbreak cases. spatial-temporal cluster analysis is used to analyze the spatial or temporal distribution of agglomeration disease, examine whether its distribution is statistically significant. Local clusters were investigated using Kulldorff's scan statistic approach. The result reveals that the epidemic mainly gathered in the western part of Africa near north Atlantic with obvious regional distribution. For the current epidemic, we have found areas in high incidence of EVD by means of spatial cluster analysis.

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

    PubMed Central

    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

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

    PubMed

    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.

  15. Multivariate Prediction of Total Water Storage Changes Over West Africa from Multi-Satellite Data

    NASA Astrophysics Data System (ADS)

    Forootan, Ehsan; Kusche, Jürgen; Loth, Ina; Schuh, Wolf-Dieter; Eicker, Annette; Awange, Joseph; Longuevergne, Laurent; Diekkrüger, Bernd; Schmidt, Michael; Shum, C. K.

    2014-07-01

    West African countries have been exposed to changes in rainfall patterns over the last decades, including a significant negative trend. This causes adverse effects on water resources of the region, for instance, reduced freshwater availability. Assessing and predicting large-scale total water storage (TWS) variations are necessary for West Africa, due to its environmental, social, and economical impacts. Hydrological models, however, may perform poorly over West Africa due to data scarcity. This study describes a new statistical, data-driven approach for predicting West African TWS changes from (past) gravity data obtained from the gravity recovery and climate experiment (GRACE), and (concurrent) rainfall data from the tropical rainfall measuring mission (TRMM) and sea surface temperature (SST) data over the Atlantic, Pacific, and Indian Oceans. The proposed method, therefore, capitalizes on the availability of remotely sensed observations for predicting monthly TWS, a quantity which is hard to observe in the field but important for measuring regional energy balance, as well as for agricultural, and water resource management. Major teleconnections within these data sets were identified using independent component analysis and linked via low-degree autoregressive models to build a predictive framework. After a learning phase of 72 months, our approach predicted TWS from rainfall and SST data alone that fitted to the observed GRACE-TWS better than that from a global hydrological model. Our results indicated a fit of 79 % and 67 % for the first-year prediction of the two dominant annual and inter-annual modes of TWS variations. This fit reduces to 62 % and 57 % for the second year of projection. The proposed approach, therefore, represents strong potential to predict the TWS over West Africa up to 2 years. It also has the potential to bridge the present GRACE data gaps of 1 month about each 162 days as well as a—hopefully—limited gap between GRACE and the GRACE

  16. Infrared radiation budget of the Harmattan haze. [West Africa

    NASA Technical Reports Server (NTRS)

    Kuhn, P. M.; Weickmann, H. K.

    1975-01-01

    Infrared in situ observations of the West African Harmaltan Haze during the 1974 GATE field phase were conducted to determine the radiative properties of the tropospheric phenomenon and to develop a calculation model for radiative transfer through the haze. Radiometric observations of the dust haze were analyzed for haze infrared transmission. Infrared and tropospheric cooling rates are given together with the haze volume absorption rate.

  17. Infrared radiation budget of the Harmattan haze. [West Africa

    NASA Technical Reports Server (NTRS)

    Kuhn, P. M.; Weickmann, H. K.

    1975-01-01

    Infrared in situ observations of the West African Harmaltan Haze during the 1974 GATE field phase were conducted to determine the radiative properties of the tropospheric phenomenon and to develop a calculation model for radiative transfer through the haze. Radiometric observations of the dust haze were analyzed for haze infrared transmission. Infrared and tropospheric cooling rates are given together with the haze volume absorption rate.

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

    NASA Astrophysics Data System (ADS)

    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).

  19. Future impacts of global warming and reforestation on drought patterns over West Africa

    NASA Astrophysics Data System (ADS)

    Diasso, Ulrich; Abiodun, Babatunde J.

    2017-07-01

    This study investigates how a large-scale reforestation in Savanna (8-12°N, 20°W-20°E) could affect drought patterns over West Africa in the future (2031-2060) under the RCP4.5 scenario. Simulations from two regional climate models (RegCM4 and WRF) were analyzed for the study. The study first evaluated the performance of both RCMs in simulating the present-day climate and then applied the models to investigate the future impacts of global warming and reforestation on the drought patterns. The simulated and observed droughts were characterized with the Standardized Precipitation and Evapotranspiration Index (SPEI), and the drought patterns were classified using a Self-organizing Map (SOM) technique. The models capture essential features in the seasonal rainfall and temperature fields (including the Saharan Heat Low), but struggle to reproduce the onset and retreat of the West African Monsoon as observed. Both RCMs project a warmer climate (about 1-2 °C) over West Africa in the future. They do not reach a consensus on future change in rainfall, but they agree on a future increase in frequency of severe droughts (by about 2 to 9 events per decade) over the region. They show that reforestation over the Savanna could reduce the future warming by 0.1 to 0.8 °C and increase the precipitation by 0.8 to 1.2 mm per day. However, the impact of reforestation on the frequency of severe droughts is twofold. While reforestation decreases the droughts frequency (by about 1-2 events per decade) over the Savanna and Guinea coast, it increases droughts frequency (by 1 event per decade) over the Sahel, especially in July to September. The results of this study have application in using reforestation to mitigate impacts of climate change in West Africa.

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

    PubMed

    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.

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

    NASA Astrophysics Data System (ADS)

    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.

  2. The West Africa Field Epidemiology and Laboratory Training Program, a strategy to improve disease surveillance and epidemic control in West Africa

    PubMed Central

    Mutabaruka, Evariste; Sawadogo, Mamadou; Tarnagda, Zekiba; Ouédraogo, Lauren; Sangare, Lassana; Ousmane, Badolo; Ndjakani, Yassa; Namusisi, Olivia; Mukanga, David; Evering-Watley, Michele; Hounton, Sennen; Nsubuga, Peter

    2011-01-01

    The West Africa Field Epidemiology and Laboratory Training Program (WA-FELTP) which was established in September 2007, is an inter-country, competency-based, in-service and post -graduate training program in applied epidemiology and public health that builds the capacity to strengthen the surveillance and response system as well as epidemic control in the French-speaking countries where they are implemented. The overall purpose is to provide epidemiological and public health laboratory services to the public health systems at national, provincial, district and local levels. The program includes four countries: Burkina Faso, Mali, Niger, and Togo with an overarching goal to progressively cover all French speaking countries in West Africa through a phased-in approach. WA-FELTP's 2- year Master's program was launched in 2010 with 12 residents, three from each country, and consists of medical and veterinary doctors, pharmacists, and laboratory scientists. The training comprises 25% didactic sessions and 75% practical in-the-field mentored training. During the practical training, residents rovide service to their respective ministries of health and ministries of animal resources by contributing to outbreak investigations and activities that help to improve national surveillance systems at national, regional, district and local levels. The pressing challenges that the program must address consist of the lack of funds to support the second cohort of trainees, though trainee selection was completed, inadequate funds to support staff compensation, and shortage of funds to support trainees’ participation in critical activities in field epidemiology practice, and a need to develop a 5-year plan for sustainability. PMID:22359698

  3. The West Africa Field Epidemiology and Laboratory Training Program, a strategy to improve disease surveillance and epidemic control in West Africa.

    PubMed

    Mutabaruka, Evariste; Sawadogo, Mamadou; Tarnagda, Zekiba; Ouédraogo, Lauren; Sangare, Lassana; Ousmane, Badolo; Ndjakani, Yassa; Namusisi, Olivia; Mukanga, David; Evering-Watley, Michele; Hounton, Sennen; Nsubuga, Peter

    2011-01-01

    The West Africa Field Epidemiology and Laboratory Training Program (WA-FELTP) which was established in September 2007, is an inter-country, competency-based, in-service and post -graduate training program in applied epidemiology and public health that builds the capacity to strengthen the surveillance and response system as well as epidemic control in the French-speaking countries where they are implemented. The overall purpose is to provide epidemiological and public health laboratory services to the public health systems at national, provincial, district and local levels. The program includes four countries: Burkina Faso, Mali, Niger, and Togo with an overarching goal to progressively cover all French speaking countries in West Africa through a phased-in approach. WA-FELTP's 2- year Master's program was launched in 2010 with 12 residents, three from each country, and consists of medical and veterinary doctors, pharmacists, and laboratory scientists. The training comprises 25% didactic sessions and 75% practical in-the-field mentored training. During the practical training, residents rovide service to their respective ministries of health and ministries of animal resources by contributing to outbreak investigations and activities that help to improve national surveillance systems at national, regional, district and local levels. The pressing challenges that the program must address consist of the lack of funds to support the second cohort of trainees, though trainee selection was completed, inadequate funds to support staff compensation, and shortage of funds to support trainees' participation in critical activities in field epidemiology practice, and a need to develop a 5-year plan for sustainability.

  4. Secondhand Smoke Exposure Among Nonsmoking Adolescents in West Africa

    PubMed Central

    Veeranki, Sreenivas P.; Kioko, David M.; Ogwell Ouma, Ahmed E.

    2015-01-01

    Objectives. We estimated the prevalence and determinants of secondhand smoke (SHS) exposure among nonsmoking adolescents in 9 West African countries. Methods. We conducted a pooled analysis with nationally representative 2006 to 2009 Global Youth Tobacco Survey data. We used descriptive statistics to determine the prevalence of SHS exposure and inferential statistics using a multivariable logistic regression model to determine factors associated with SHS exposure. We investigated average marginal effect results that show the probability of SHS exposure, adjusting for all other attributes. Results. SHS exposure inside the home ranged from 13.0% to 45.0%; SHS exposure outside the home ranged from 24.7% to 80.1%. Parental or peer smoking behaviors were significantly associated with higher probability of SHS exposure in all 9 countries. Knowledge of smoking harm, support for smoking bans, exposure to antismoking media messages, and receptivity of school tobacco education were significantly associated with higher SHS exposure in most countries. Conclusions. West African policymakers should adopt policies consistent with Article 8 of the World Health Organization Framework Convention on Tobacco Control and its guidelines and public health education to promote smoke-free households. PMID:26180960

  5. Ostracod provincialism and migration as a response to movements of Earth's plates: Cretaceous-Paleogene ostracods of West Africa, North Africa and the Middle East

    NASA Astrophysics Data System (ADS)

    Elewa, Ashraf M. T.

    2017-10-01

    This paper documents the Cretaceous -Paleogene ostracods response as the continental plates tend to show divergence. For example, in the intervals from the Early to Late Cretaceous when the South American plate tended to exhibit divergent movement westward from the African plate, the migration of ostracods show westward trend from Northeast Africa to West Africa; whereas, the divergence of the Indian and the Australian plates as well as the Antarctic plate from the African and the Eurasian plates, and Arabia is accompanied with ostracod migration southward. Another example from the Maastrichtian-Eocene ostracods of West Africa, where ostracods exhibit east-west migration (despite the migration of epineritic ostracods in both directions; east-west and vice-versa) towards the North American and South American plates. These trends of migration towards the deep oceans (Atlantic and Indian oceans of present time) indicate the tendency of ostracods of these geologic times towards endemism in the deep oceans resulted from seafloor spreading during the divergence of the continental plates. On the other hand, the paleoenvironmental changes should also have significant effect on these trends of migration.

  6. Diagnosis and Modelling of the Variability of Rainfall in West Africa Within the Impetus Project

    NASA Astrophysics Data System (ADS)

    Fink, A. H.; Born, K.; Hense, A.; Kerschgens, M.; Paeth, H.; Schulz, J.; Simmer, C.; Sogalla, M.; Speth, P.

    2003-04-01

    In the meteorological sub-project of the multi-disciplinary IMPETUS project ('An Integrated Approach to the Efficient Management of Scarce Water Resources in West Africa'), one focus is on the diagnosis and modelling of the major rainfall producing weather systems in Benin and Morocco. Two other foci are on model sensitivity studies to determine the potential of seasonal rainfall forecasting for tropical West Africa, as well as on the impact of land surface characteristics on rainfall patterns. Recent analysis of precipitation trends reveals no return to normal or above-normal monsoon rains in all climatic zones of tropical West Africa. In Morocco, a series of dry winters in the winter-precipitation regime north of the High Atlas occurred in the 1980s and 1990s, while at the Saharan foothills of the Atlas Mountains, wetter than normal conditions prevailed. This behaviour might be explained by a hitherto poorly examined contribution of "Tropical Extratropical Interaction" (TEI) events to the mean annual rainfall south of the Atlas mountains. Such TEI most often occur in the transition seasons and cause convective rainfall events that are supplied with water vapour from tropical moisture plumes. In the West African Tropics, the effect of interactions between the earth's surface and the atmosphere on fresh water availability is investigated with a non-hydrostatic mesoscale model for a river catchment in Benin. Idealised ensemble studies exhibit a dominant influence of initial soil water content and an enhanced dependence of precipitation on vegetation when soil water availability is reduced. It is also shown that a successive increase of the fraction of degraded land surface results in a nearly linear response of moderate rainfall decrease for the area as a whole and a tendency to strong reductions in some regions. Finally, observational data sets and output from the global (ECHAM4) and continental (REMO) general circulation models are used to determine the potential

  7. The DACCIWA project: Dynamics-aerosol-chemistry-cloud interactions in West Africa

    NASA Astrophysics Data System (ADS)

    Knippertz, Peter

    2017-04-01

    This contribution provides an overview of the EU-funded DACCIWA (Dynamics-Aerosol-Chemistry-Cloud Interactions in West Africa) project. DACCIWA consists of 16 European and African research organisations and has strong links to universities, weather services and government organisations across West Africa. The project runs from 2010 to 2018 and is built around a major international field campaign in 2016. A key motivation for DACCIWA is the expected tripling of anthropogenic emissions in southern West Africa (SWA) between 2000 and 2030, whose impacts on human health, ecosystems, food security and the regional climate are largely unknown. An integrated assessment of this problem, which is mostly due to massive economic and population growth and urbanization, is challenging due to (a) a superposition of regional effects with global climate change, (b) a strong dependence on the variable West African monsoon, (c) incomplete scientific understanding of interactions between emissions, clouds, radiation, precipitation and regional circulations, and (d) a lack of observations. DACCIWA combines measurements in the field in SWA with extensive modelling activities and work on satellite data. In particular during the main DACCIWA field campaign in June-July 2016 high-quality observations of emissions, atmospheric composition and meteorological parameters were sampled. The campaign involved three research aircraft, three ground-based supersites, enhanced radiosonde launches, and intensive measurements at urban sites in Abidjan and Cotonou. These data have already been quality-controlled and will be freely available to the research community through a database at http://baobab.sedoo.fr/DACCIWA/ after the end of the project. The resulting benchmark dataset is currently combined with a wide range of modelling and satellite-based research activities that will ultimately allow (a) an assessment of the roles of relevant physical, chemical and biological processes, (b) an improvement

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

    NASA Astrophysics Data System (ADS)

    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

  9. An Inquiry-based Astronomy Summer School in West Africa

    NASA Astrophysics Data System (ADS)

    Strubbe, Linda; Okere, Bonaventure; Chibueze, James; Lepo, Kelly; White, Heidi; Zhang, Jielai; Okoh, Daniel; Reid, Mike; Hunter, Lisa

    2015-01-01

    In October 2013 over 75 undergraduate science students and teachers from Nigeria and Ghana attended the week-long West African International Summer School for Young Astronomers. The school was organized by a collaboration of astronomers from the University of Toronto, the University of Nigeria, and the Nigerian National Space Research and Development Agency. We designed and led activities that taught astronomy content, promoted students' self-identity as scientists, and encouraged students to think critically and figure out solutions themselves. I will describe the inquiry-based and active learning techniques used in the school, share results from the qualitative and quantitative evaluations of student performance, and describe future plans for holding the school in 2015, supporting our alumni, and building a sustainable partnership between North American and Nigerian universities.

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

    NASA Astrophysics Data System (ADS)

    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.

  11. The problem of suboptimal complementary feeding practices in West Africa: what is the way forward?

    PubMed

    Issaka, Abukari I; Agho, Kingsley E; Page, Andrew N; Burns, Penelope L; Stevens, Garry J; Dibley, Michael J

    2015-10-01

    The objective of this paper was to review the policy implications of inadequate complementary feeding among children aged 6-23 months in West Africa. The review was undertaken from the initial results and findings from a series of studies on the comparison of complementary feeding indicators among children aged 6-23 months in four anglophone and seven francophone West African countries. It also examined a study of the determinants of suboptimal complementary feeding practices among children aged 6-23 months in those countries. Among the four complementary feeding indicators, it was only the introduction of solid, semi-solid or soft foods that was adequate among children in all the West African countries surveyed. The rates of the other complementary feeding indicators were found to be inadequate in all countries surveyed, although relatively better among children in the anglophone countries. Alarmingly, low rates of minimum acceptable diet were reported among children from both the anglophone and the francophone countries. Infants 6-11 months of age, children living in poor households, administrative/geographical regional differences and mothers' access to the media were some of the common risk factors for optimal complementary feeding practices in these countries. Assessing complementary feeding indicators and determinants of suboptimal complementary feeding practices in these West African countries is crucial to improving infant and young child feeding practices. It is recommended that governments and stakeholders of the West African countries studied make greater efforts to improve these critical practices in order to reduce child morbidity and mortality in the West Africa sub-region. Intervention studies on complementary feeding should target those socio-demographic factors that pose risks to optimal complementary feeding.

  12. Ocean climate data for user community in West and Central Africa: Needs, opportunities, and challenges

    NASA Technical Reports Server (NTRS)

    Ojo, S. O.

    1992-01-01

    The urgent need to improve data delivery systems needed by scientists studying ocean role in climate and climate characteristics has been manifested in recent years because of the unprecedented climatic events experienced in many parts of the world. Indeed, there has been a striking and growing realization by governments and the general public indicating that national economies and human welfare depend on climate and its variability. In West and Central Africa, for instance climatic events, which have resulted in floods and droughts, have caused a lot of concern to both governments and people of the region. In particular, the droughts have been so widespread that greater awareness and concern have become generated for the need to find solutions to the problems created by the consequences of the climatic events. Particularly in the southern border regions of the Sahara Desert as well as in the Sahel region, the drought episodes considerably reduced food production and led to series of socioeconomic problems, not only in the areas affected by the droughts, but also in the other parts of West Africa. The various climatic variabilities which have caused the climatic events are no doubt related to the ocean-atmosphere interactions. Unfortunately, not much has been done on the understanding of these interactions, particularly as they affect developing countries. Indeed, not much has been done to develop programs which will reflect the general concerns and needs for researching into the ocean-atmosphere systems and their implications on man-environmental systems in many developing countries. This is for example, true of West and Central Africa, where compared with the middle latitude countries, much less is known about the characteristics of the ocean-atmosphere systems and their significance on man-environmental systems of the area.

  13. Long-Term Water Balance of the Volta River Basin in West Africa

    NASA Astrophysics Data System (ADS)

    van de Giesen, N.; Andreini, M.; Taylor, J.; Steenhuis, T.

    2002-12-01

    The Volta River drains approximately 400,000 km2 of the semi-arid to sub-humid savanna of West Africa. Average rainfall is about 1000 mm per year. The interannual variation is relatively low with a coefficient of variation of 0.07. Most rainfall returns to the atmosphere as evapotranspiration and only 9% becomes available as river runoff. The interannual variation of river flow is much higher than that of rainfall and has a coefficient of variation of 0.57. In this presentation, the coupling between interannual variation in rainfall and runoff is examined. To a large extent, the high variability in river flow can be explained with the relatively small differences in rainfall between years; the watershed strongly amplifies the atmospheric input. The amplifying effect is, however, not constant over space and time. Over all, the basin received less rain than before in the past two decades. Some parts of the basin did indeed produce less runoff but other parts actually produced more runoff, most likely due to changes in landuse. No clear increase or decrease in the interannual variability could be found for different parts of the basin. To examine the interannual variability of water resources availability under future climates, the applicability of General Circulation Models (GCMs) was examined for West Africa. Comparison of historical and GCM rainfall data showed large discrepancies. Different approaches exist to adjust GCM rainfall with the aid of historical rainfall data but for West Africa some problems remained. This presentation concludes with a focus on differences in mid-term (2-10 years) persistence in annual river flow as produced by historical and GCM data.

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

    PubMed

    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

    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. 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). 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). 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.

  15. Model-Based Geostatistical Mapping of the Prevalence of Onchocerca volvulus in West Africa

    PubMed Central

    O’Hanlon, Simon J.; Slater, Hannah C.; Cheke, Robert A.; Boatin, Boakye A.; Coffeng, Luc E.; Pion, Sébastien D. S.; Boussinesq, Michel; Zouré, Honorat G. M.; Stolk, Wilma A.; Basáñez, María-Gloria

    2016-01-01

    Background The initial endemicity (pre-control prevalence) of onchocerciasis has been shown to be an important determinant of the feasibility of elimination by mass ivermectin distribution. We present the first geostatistical map of microfilarial prevalence in the former Onchocerciasis Control Programme in West Africa (OCP) before commencement of antivectorial and antiparasitic interventions. Methods and Findings Pre-control microfilarial prevalence data from 737 villages across the 11 constituent countries in the OCP epidemiological database were used as ground-truth data. These 737 data points, plus a set of statistically selected environmental covariates, were used in a Bayesian model-based geostatistical (B-MBG) approach to generate a continuous surface (at pixel resolution of 5 km x 5km) of microfilarial prevalence in West Africa prior to the commencement of the OCP. Uncertainty in model predictions was measured using a suite of validation statistics, performed on bootstrap samples of held-out validation data. The mean Pearson’s correlation between observed and estimated prevalence at validation locations was 0.693; the mean prediction error (average difference between observed and estimated values) was 0.77%, and the mean absolute prediction error (average magnitude of difference between observed and estimated values) was 12.2%. Within OCP boundaries, 17.8 million people were deemed to have been at risk, 7.55 million to have been infected, and mean microfilarial prevalence to have been 45% (range: 2–90%) in 1975. Conclusions and Significance This is the first map of initial onchocerciasis prevalence in West Africa using B-MBG. Important environmental predictors of infection prevalence were identified and used in a model out-performing those without spatial random effects or environmental covariates. Results may be compared with recent epidemiological mapping efforts to find areas of persisting transmission. These methods may be extended to areas where

  16. Small-incision manual extracapsular cataract surgery in Ghana, West Africa.

    PubMed

    Guzek, James Paul; Ching, Andrea

    2003-01-01

    To evaluate the results of small-incision manual extracapsular cataract extraction surgery (ECCE) in a district hospital in West Africa. Margret Marquart Catholic Hospital, Ghana, West Africa. This prospective study consisted of 200 eyes of 193 patients who had small-incision manual ECCE between January 1999 and May 2000. For comparison, the charts of 32 patients (32 eyes) operated on between July and December 1998 using a limbal incision (control group) were retrospectively analyzed. Outcome measures included intraoperative and postoperative complications, postoperative visual acuity, and refractive astigmatism. In the small-incision ECCE group, self-sealing wounds were achieved in 129 eyes (64.5%). Vitreous loss occurred in approximately 3% of eyes in both the small-incision and control groups. The final visual acuities were similar between the 2 groups, with more than 90% of eyes in both groups achieving a final best corrected visual acuity of at least 20/60. Eyes in the small-incision group had faster visual recovery (P <.001), a lower incidence of fibrinous iritis (P =.02), and were more likely to have round pupils (P <.001) than eyes in the control group. The main complication of small-incision surgery was moderate corneal edema, which persisted until at least the 1-week visit in 14 eyes (7%). At the most recent visit, 1 eye in the small-incision group (0.5%) had bullous keratopathy. In a district hospital in West Africa, small-incision manual ECCE surgery yielded faster visual rehabilitation and had a lower incidence of fibrinous iritis than standard ECCE surgery.

  17. Potential Risk of Regional Disease Spread in West Africa through Cross-Border Cattle Trade

    PubMed Central

    Dean, Anna S.; Fournié, Guillaume; Kulo, Abalo E.; Boukaya, G. Aboudou; Schelling, Esther; Bonfoh, Bassirou

    2013-01-01

    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. PMID:24130721

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

    NASA Astrophysics Data System (ADS)

    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

  19. Decomposing Wealth-Based Inequalities in Under-Five Mortality in West Africa

    PubMed Central

    BADO, Aristide Romaric; APPUNNI, Sathiya Susuman

    2015-01-01

    Background: This study aimed to analysis the inequalities of mortality of children under 5 years in West Africa by examining the determinants and contributing factors to the overall inequality concentration in these countries. Method: Data used came from the DHS surveys conducted in the six countries in West Africa: Burkina Faso (2010), Benin (2006), Cote d’Ivoire 2011), Ghana (2008), Mali (2006), Nigeria (2008) and Niger (2012). The concentration index (CI) and Generalized Linear Model (GLM) with logit link were used to access inequality. Results: The results show that in all countries, the poorest Q1 have the highest proportions of deaths: Nigeria (31.4%), Cote d’Ivoire (30.4%) and Ghana (36.4%), over 30% of deaths of children under 5 years are among the children of the poorest (Q1) and the absolute differences of proportions Q1–Q5 are more than 20 points (25.8 in Ghana and 23.6 in Nigeria). The contributing factors of inequalities of child mortality were birth order, maternal age, parity and household size. Our findings also showed that the intensity of inequality varies from one country to another. Conclusion: The most important conclusion of this study is to reduce mortality in children under 5 years, it is needed to reduce economic and social inequalities and improve the country’s economic and social condition. There is a need for monitoring and assessment inequalities by leading causes of death and morbidity among children in the region in order to advance in understanding the gaps and finding a way to reduce them in West Africa countries. PMID:26576370

  20. Mapping distributions of chromosomal forms of Anopheles gambiae in West Africa using climate data.

    PubMed

    Bayoh, M N; Thomas, C J; Lindsay, S W

    2001-09-01

    The mosquito Anopheles gambiae Giles sensu stricto (Diptera: Culicidae), the principal vector of malaria in West Africa, comprises several chromosomal forms (e.g. Bissau, Forest, Mopti, Savanna) associated with climatic zones. Here we show how climate data can be used to map the geographical distribution of these chromosomal forms. The climate at 144 sites surveyed for mosquitoes in West Africa between 1971 and 92 was determined using computerized climate surfaces. Forest and Bissau forms occurred at relatively wet sites: median annual precipitation 1325 mm and 1438 mm, respectively, interquartile ranges (IQR) 1144-1858 mm and 1052-1825 mm), whilst the Mopti form was found at dry sites (annual 938 mm, IQR 713-1047 mm) and the Savanna form at sites intermediate between the wet and dry forms (annual 1067 mm, IQR 916-1279). Logistic regression analyses of the climate variables were carried out on a stratified random sample of half the sites. The resulting models correctly classified over 80% of the sites for presence or absence of each chromosomal form. When these models were tested against excluded sites they were also correct at over 80% of sites. The combined data produced models that were correct at over 86% of sites. Mean annual precipitation, evapotranspiration, minimum temperature and maximum temperature were the most important climate variables correlated with the distribution of these forms of An. gambiae. We used the logistic models to map the distribution of each chromosomal form within the reported range for An. gambiae s.s. in West Africa employing a geographical information system. Our maps indicate that each chromosomal form favours particular climate envelopes in well-defined ecoclimatic zones, although these forms are sympatric at the edges of their ranges. This study demonstrates that climate can be used to map the distribution of chromosomal forms of insects across large areas.

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

    NASA Astrophysics Data System (ADS)

    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.

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

    NASA Astrophysics Data System (ADS)

    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.

  3. Ebola viral hemorrhagic disease outbreak in West Africa- lessons from Uganda.

    PubMed

    Mbonye, Anthony K; Wamala, Joseph F; Nanyunja, Miriam; Opio, Alex; Makumbi, Issa; Aceng, Jane Ruth

    2014-09-01

    There has been a rapid spread of Ebola Viral Hemorrhagic disease in Guinea, Liberia and Sierra Leone since March 2014. Since this is the first time of a major Ebola outbreak in West Africa; it is possible there is lack of understanding of the epidemic in the communities, lack of experience among the health workers to manage the cases and limited capacities for rapid response. The main objective of this article is to share Uganda's experience in controlling similar Ebola outbreaks and to suggest some lessons that could inform the control of the Ebola outbreak in West Africa. The article is based on published papers, reports of previous Ebola outbreaks, response plans and experiences of individuals who have participated in the control of Ebola epidemics in Uganda. Lessons learnt: The success in the control of Ebola epidemics in Uganda has been due to high political support, effective coordination through national and district task forces. In addition there has been active surveillance, strong community mobilization using village health teams and other community resources persons, an efficient laboratory system that has capacity to provide timely results. These have coupled with effective case management and infection control and the involvement of development partners who commit resources with shared responsibility. Several factors have contributed to the successful quick containment of Ebola outbreaks in Uganda. West African countries experiencing Ebola outbreaks could draw some lessons from the Uganda experience and adapt them to contain the Ebola epidemic.

  4. Lineage 2 West Nile Virus as Cause of Fatal Neurologic Disease in Horses, South Africa

    PubMed Central

    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

    2009-01-01

    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. PMID:19523285

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

    PubMed

    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.

  6. Ebola virus in West Africa: waiting for the owl of Minerva.

    PubMed

    Upshur, Ross E G

    2014-12-01

    The evolving Ebola epidemic in West Africa is unprecedented in its size and scope, requiring the rapid mobilization of resources. It is too early to determine all of the ethical challenges associated with the outbreak, but these should be monitored closely. Two issues that can be discussed are (1) the decision to implement and evaluate unregistered agents to determine therapeutic or prophylactic safety and efficacy and (2) the justification behind this decision. In this paper, I argue that it is not compassionate use that justifies this decision and suggest three lines of reasoning to support the decision.

  7. Cost-effectiveness analysis of malaria chemoprophylaxis for travellers to West-Africa

    PubMed Central

    2010-01-01

    Background The importation of malaria to non-endemic countries remains a major cause of travel-related morbidity and a leading cause of travel-related hospitalizations. Currently they are three priority medications for malaria prophylaxis to West Africa: mefloquine, atovaquone/proguanil and doxycycline. We investigate the cost effectiveness of a partial reimbursement of the cheapest effective malaria chemoprophylaxis (mefloquine) for travellers to high risk areas of malaria transmission compared with the current situation of no reimbursement. Methods This study is a cost-effectiveness analysis based on malaria cases imported from West Africa to Switzerland from the perspective of the Swiss health system. We used a decision tree model and made a literature research on the components of travel related malaria. The main outcome measure was the cost effectiveness of malaria chemoprophylaxis reimbursement based on malaria and deaths averted. Results Using a program where travellers would be reimbursed for 80% of the cost of the cheapest malaria chemoprophylaxis is dominant (i.e. cost saving and more effective than the current situation) using the assumption that currently 68.7% of travellers to West Africa use malaria chemoprophylaxis. If the current usage of malaria chemoprophylaxis would be higher, 82.4%, the incremental cost per malaria case averted is € 2'302. The incremental cost of malaria death averted is € 191'833. The most important factors influencing the model were: the proportion of travellers using malaria chemoprophylaxis, the probability of contracting malaria without malaria chemoprophylaxis, the cost of the mefloquine regimen, the decrease in the number of travellers without malaria chemoprophylaxis in the reimbursement strategy. Conclusions This study suggests that a reimbursement of 80% of the cost of the cheapest effective malaria chemoprophylaxis (mefloquine) for travellers from Switzerland to West Africa is highly effective in terms of malaria

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

    PubMed

    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.

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

    PubMed

    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

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

    PubMed Central

    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

  11. Identification of essential outstanding questions for an adequate European laboratory response to Ebolavirus Zaire West Africa 2014.

    PubMed

    Reusken, Chantal; Niedrig, Matthias; Pas, Suzan; Anda, Pedro; Baize, Sylvain; Charrel, Remi; Di Caro, Antonino; Drosten, Christian; Fernandez-Garcia, Maria Dolores; Franco, Leticia; Gunther, Stephan; Leparc-Goffart, Isabelle; Martina, Byron; Pannetier, Delphine; Papa, Anna; Sanchez-Seco, Maria Paz; Vapalahti, Olli; Koopmans, Marion

    2015-01-01

    On August 8 2014, the World Health Organization (WHO) declared the outbreak of Ebola Virus Disease (EVD) evolving in West Africa since December 2013, a Public Health Emergency of International Concern (PHEIC). It is expected that the outbreak of Ebolavirus Disease (EVD) in West Africa will lead to increased testing of individuals in Europe for EVD. The severity of the situation in West Africa warranted a critical appraisal of the laboratory preparedness and response for EVD, with a focus on information needs for laboratories involved in diagnostics of rare viral diseases associated with the European Network for the Diagnostics of "Imported" Viral Diseases", ENIVD. Essential knowledge and knowledge gaps for an adequate laboratory response focusing on virus properties, infection kinetics, tests specifics and field performances were identified. An inventory of the laboratory capacity for EVD diagnostics among ENIVD laboratories was made.

  12. Improving agricultural drought monitoring in West Africa using root zone soil moisture estimates derived from NDVI

    NASA Astrophysics Data System (ADS)

    McNally, A.; Funk, C. C.; Yatheendradas, S.; Michaelsen, J.; Cappelarere, B.; Peters-Lidard, C. D.; Verdin, J. P.

    2012-12-01

    The Famine Early Warning Systems Network (FEWS NET) relies heavily on remotely sensed rainfall and vegetation data to monitor agricultural drought in Sub-Saharan Africa and other places around the world. Analysts use satellite rainfall to calculate rainy season statistics and force crop water accounting models that show how the magnitude and timing of rainfall might lead to above or below average harvest. The Normalized Difference Vegetation Index (NDVI) is also an important indicator of growing season progress and is given more weight over regions where, for example, lack of rain gauges increases error in satellite rainfall estimates. Currently, however, near-real time NDVI is not integrated into a modeling framework that informs growing season predictions. To meet this need for our drought monitoring system a land surface model (LSM) is a critical component. We are currently enhancing the FEWS NET monitoring activities by configuring a custom instance of NASA's Land Information System (LIS) called the FEWS NET Land Data Assimilation System. Using the LIS Noah LSM, in-situ measurements, and remotely sensed data, we focus on the following questions: What is the relationship between NDVI and in-situ soil moisture measurements over the West Africa Sahel? How can we use this relationship to improve modeled water and energy fluxes over the West Africa Sahel? We investigate soil moisture and NDVI cross-correlation in the time and frequency domain to develop a transfer function model to predict soil moisture from NDVI. This work compares sites in southwest Niger, Benin, Burkina Faso, and Mali to test the generality of the transfer function. For several sites with fallow and millet vegetation in the Wankama catchment in southwest Niger we developed a non-parametric frequency response model, using NDVI inputs and soil moisture outputs, that accurately estimates root zone soil moisture (40-70cm). We extend this analysis by developing a low order parametric transfer function

  13. Identifying the pattern of molecular evolution for Zaire ebolavirus in the 2014 outbreak in West Africa.

    PubMed

    Liu, Si-Qing; Deng, Cheng-Lin; Yuan, Zhi-Ming; Rayner, Simon; Zhang, Bo

    2015-06-01

    The current Ebola virus disease (EVD) epidemic has killed more than all previous Ebola outbreaks combined and, even as efforts appear to be bringing the outbreak under control, the threat of reemergence remains. The availability of new whole-genome sequences from West Africa in 2014 outbreak, together with those from the earlier outbreaks, provide an opportunity to investigate the genetic characteristics, the epidemiological dynamics and the evolutionary history for Zaire ebolavirus (ZEBOV). To investigate the evolutionary properties of ZEBOV in this outbreak, we examined amino acid mutations, positive selection, and evolutionary rates on the basis of 123 ZEBOV genome sequences. The estimated phylogenetic relationships within ZEBOV revealed that viral sequences from the same period or location formed a distinct cluster. The West Africa viruses probably derived from Middle Africa, consistent with results from previous studies. Analysis of the seven protein regions of ZEBOV revealed evidence of positive selection acting on the GP and L genes. Interestingly, all putatively positive-selected sites identified in the GP are located within the mucin-like domain of the solved structure of the protein, suggesting a possible role in the immune evasion properties of ZEBOV. Compared with earlier outbreaks, the evolutionary rate of GP gene was estimated to significantly accelerate in the 2014 outbreak, suggesting that more ZEBOV variants are generated for human to human transmission during this sweeping epidemic. However, a more balanced sample set and next generation sequencing datasets would help achieve a clearer understanding at the genetic level of how the virus is evolving and adapting to new conditions.

  14. Exploring the Diversity of Field Strains of Brucella abortus Biovar 3 Isolated in West Africa

    PubMed Central

    Sanogo, Moussa; Fretin, David; Thys, Eric; Saegerman, Claude

    2017-01-01

    Brucellosis is one of the most widespread bacterial zoonotic diseases in the world, affecting both humans and domestic and wild animals. Identification and biotyping of field strains of Brucella are of key importance for a better knowledge of the epidemiology of brucellosis, for identifying appropriate antigens, for managing disease outbreaks and for setting up efficient preventive and control programmes. Such data are required both at national and regional level to assess potential threats for public health. Highly discriminative genotyping methods such as the multiple locus variable number of tandem repeats analysis (MLVA) allow the comparison and assessment of genetic relatedness between field strains of Brucella within the same geographical area. In this study, MLVA biotyping data retrieved from the literature using a systematic review were compared using a clustering analysis and the Hunter-Gaston diversity index (HGDI). Thus, the analysis of the 42 MLVA genotyping results found in the literature on West Africa [i.e., from Ivory Coast (1), Niger (1), Nigeria (34), The Gambia (3), and Togo (3)] did not allow a complete assessment of the actual diversity among field strains of Brucella. However, it provided some preliminary indications on the co-existence of 25 distinct genotypes of Brucella abortus biovar 3 in this region with 19 genotypes from Nigeria, three from Togo and one from Ivory Coast, The Gambia, and Niger. The strong and urgent need for more sustainable molecular data on prevailing strains of Brucella in this sub-region of Africa and also on all susceptible species including humans is therefore highlighted. This remains a necessary stage to allow a comprehensive understanding of the relatedness between field strains of Brucella and the epidemiology of brucellosis within West Africa countries. PMID:28713359

  15. Genetic Diversity of Newcastle Disease Virus in Wild Birds and Pigeons in West Africa

    PubMed Central

    Snoeck, Chantal J.; Adeyanju, Adeniyi T.; Owoade, Ademola A.; Couacy-Hymann, Emmanuel; Alkali, Bello R.; Ottosson, Ulf

    2013-01-01

    In West and Central Africa, virulent Newcastle disease virus (NDV) strains of the recently identified genotypes XIV, XVII, and XVIII are enzootic in poultry, representing a considerable threat to the sector. The increasing number of reports of virulent strains in wild birds at least in other parts of the world raised the question of a potential role of wild birds in the spread of virulent NDV in sub-Saharan Africa as well. We investigated 1,723 asymptomatic birds sampled at live-bird markets and sites important for wild-bird conservation in Nigeria and 19 sick or dead wild birds in Côte d'Ivoire for NDV class I and II. Typical avirulent wild-type genotype I strains were found in wild waterfowl in wetlands in northeastern Nigeria. They were unrelated to vaccine strains, and the involvement of inter- or intracontinental migratory birds in their circulation in the region is suggested. Phylogenetic analyses also revealed that genotype VI strains found in pigeons, including some putative new subgenotype VIh and VIi strains, were introduced on multiple separate occasions in Nigeria. A single virulent genotype XVIII strain was found in a dead wild bird in Côte d'Ivoire, probably as a result of spillover from sick poultry. In conclusion, screening of wild birds and pigeons for NDV revealed the presence a variety of virulent and avirulent strains in West Africa but did not provide strong evidence that wild birds play an important role in the spread of virulent strains in the region. PMID:24123735

  16. Comparative Demography of the Spider Mite, Tetranychus ludeni, on Two Host Plants in West Africa

    PubMed Central

    Adango, Etienne; Onzo, Alexis; Hanna, Rachid; Atachi, Pierre; James, Braima

    2006-01-01

    It is well recognized that the quality of host plants affects the development and survival of plant-feeding arthropods. The effects of two leafy vegetable crops, amaranth, Amaranthus cruentus L. (Caryophyllales: Amaranthaceae) and nightshade, Solanum macrocarpon L. (Solanales: Solanaceae) were examined on the development and demographic parameters of the spider mite, Tetranychus ludeni Zacher (Acari: Tetranychidae). This mite was recently identified as a pest of the two leafy vegetables which are widely used in West Africa. The experiments were conducted at the International Institute of Tropical Agriculture, Benin, West Africa, in a growth chamber at 27°C, 70% ±10% RH and 12:12 (L:D). Immature development of T. ludeni was shorter on A. cruentus than on S. macrocarpon, whereas female longevity was the same on the two vegetable crops. Total fecundity per female was higher on A. cruentus than on S. macrocarpon, largely due to longer survival of adult female T. ludeni on the former; however, no differences were observed in the daily fecundity of T. ludeni on the two plant species. The comparison of intrinsic rates of natural increase (rm), the net reproductive rates (Ro) and the survival rates of adult stage of T. ludeni on the two vegetable crops suggests that T. ludeni performs better on S. macrocarpon than on A. cruentus. Reasons for the lower rate of population growth observed on amaranth should be studied in more details as this could be used in IPM strategies such as intercropping to reduce pest density and in developing biopesticides for use against T. ludeni in vegetable farms in Africa.

  17. Genetic diversity of newcastle disease virus in wild birds and pigeons in West Africa.

    PubMed

    Snoeck, Chantal J; Adeyanju, Adeniyi T; Owoade, Ademola A; Couacy-Hymann, Emmanuel; Alkali, Bello R; Ottosson, Ulf; Muller, Claude P

    2013-12-01

    In West and Central Africa, virulent Newcastle disease virus (NDV) strains of the recently identified genotypes XIV, XVII, and XVIII are enzootic in poultry, representing a considerable threat to the sector. The increasing number of reports of virulent strains in wild birds at least in other parts of the world raised the question of a potential role of wild birds in the spread of virulent NDV in sub-Saharan Africa as well. We investigated 1,723 asymptomatic birds sampled at live-bird markets and sites important for wild-bird conservation in Nigeria and 19 sick or dead wild birds in Côte d'Ivoire for NDV class I and II. Typical avirulent wild-type genotype I strains were found in wild waterfowl in wetlands in northeastern Nigeria. They were unrelated to vaccine strains, and the involvement of inter- or intracontinental migratory birds in their circulation in the region is suggested. Phylogenetic analyses also revealed that genotype VI strains found in pigeons, including some putative new subgenotype VIh and VIi strains, were introduced on multiple separate occasions in Nigeria. A single virulent genotype XVIII strain was found in a dead wild bird in Côte d'Ivoire, probably as a result of spillover from sick poultry. In conclusion, screening of wild birds and pigeons for NDV revealed the presence a variety of virulent and avirulent strains in West Africa but did not provide strong evidence that wild birds play an important role in the spread of virulent strains in the region.

  18. West Africa

    Atmospheric Science Data Center

    2013-04-16

    ... (MISR) illustrate the abundance of atmospheric particulate matter across the region. The left-hand panels are natural-color views from ... across the region is noticeable. The distinctive area of dark green vegetation (apparent below and left of image center) are situated in ...

  19. The DACCIWA Project: Dynamics-Aerosol-Chemistry-Cloud interactions in West Africa

    NASA Astrophysics Data System (ADS)

    Knippertz, Peter

    2014-05-01

    Massive economic and population growth and urbanisation are expected to lead to a tripling of anthropogenic emissions from southern West Africa (SWA) between 2000 and 2030, the impacts of which on human health, ecosystems, food security and the regional climate are largely unknown. An assessment of these impacts is complicated by (a) a superposition with effects of global climate change, (b) the strong dependence of SWA on the sensitive West African monsoon, (c) incomplete scientific understanding of interactions between emissions, clouds, radiation, precipitation and regional circulations and (d) by a lack of observations to advance our understanding and improve predictions. The purpose of this contribution is to introduce the research consortium DACCIWA (Dynamics-Aerosol-Chemistry-Cloud interactions in West Africa), which comprises 16 partners in six European and West African countries. The interdisciplinary DACCIWA team will build on the scientific and logistical foundations established by the African Monsoon Multidisciplinary Analysis (AMMA) project and collaborate closely with operational centres. DACCIWA will receive funding of about M8.75€ from the European Commission as part of Framework Programme 7 from 2015 until 2018. The DACCIWA project will conduct extensive fieldwork in SWA to collect high-quality observations, spanning the entire process chain from surface-based natural and anthropogenic emissions to impacts on health, ecosystems and climate. This will include a major field campaign in summer 2015 with three research aircrafts and two ground-based supersites. Combining the resulting benchmark dataset with a wide range of modelling activities will allow us: (a) to assess all relevant physical and chemical processes, (b) to improve the monitoring of climate and compositional parameters from space, (c) to determine health impacts from air pollution, and (d) to develop the next generation of weather and climate models capable of representing coupled

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

    NASA Astrophysics Data System (ADS)

    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

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

    PubMed

    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.

  2. Maternal anaemia in West and Central Africa: time for urgent action.

    PubMed

    Ayoya, Mohamed Ag; Bendech, Mohamed Ag; Zagré, Noel Marie; Tchibindat, Félicité

    2012-05-01

    To review the prevalence, severity and determinants of anaemia among women in West and Central Africa (WCA) and raise awareness among policy makers and programme planners in the region. Systematic descriptive review of data in the public domain of the ORC Macro MEASURE Demographic and Health Surveys, national nutrition surveys, oral and technical communications at regional meetings, studies published in scientific journals, and WHO and UNICEF databases. West and Central Africa region. Women of childbearing age. The prevalence of anaemia among pregnant and non-pregnant women is higher than 50 % and 40 %, respectively, in all countries. Within countries, this prevalence varies by living setting (rural v. urban), women's age and education. Across countries, socio-economic and climatic differences have no apparent association with the prevalence of anaemia among women. Several factors contribute either alone or jointly to the high rates of maternal anaemia in this region. These include widespread nutritional deficiencies; high incidence of infectious diseases; low access to and poor quality of health services; low literacy rates; ineffective design, implementation and evaluation of anaemia control programmes; and poverty. Addressing the multiple causes and minimizing the consequences of anaemia on maternal and child health and development in WCA require integrated multifactorial and multisectoral strategies. This also calls for unprecedented, historical and stronger political will and commitment that put adolescent girls and maternal health at the centre of the development agenda.

  3. Calibration and uncertainty issues of a hydrological model (SWAT) applied to West Africa

    NASA Astrophysics Data System (ADS)

    Schuol, J.; Abbaspour, K. C.

    2006-09-01

    Distributed hydrological models like SWAT (Soil and Water Assessment Tool) are often highly over-parameterized, making parameter specification and parameter estimation inevitable steps in model calibration. Manual calibration is almost infeasible due to the complexity of large-scale models with many objectives. Therefore we used a multi-site semi-automated inverse modelling routine (SUFI-2) for calibration and uncertainty analysis. Nevertheless, the question of when a model is sufficiently calibrated remains open, and requires a project dependent definition. Due to the non-uniqueness of effective parameter sets, parameter calibration and prediction uncertainty of a model are intimately related. We address some calibration and uncertainty issues using SWAT to model a four million km2 area in West Africa, including mainly the basins of the river Niger, Volta and Senegal. This model is a case study in a larger project with the goal of quantifying the amount of global country-based available freshwater. Annual and monthly simulations with the "calibrated" model for West Africa show promising results in respect of the freshwater quantification but also point out the importance of evaluating the conceptual model uncertainty as well as the parameter uncertainty.

  4. Topical application of diethylcarbamazine to detect onchocerciasis recrudescence in west Africa.

    PubMed

    Toè, L; Adjami, A G; Boatin, B A; Back, C; Alley, E S; Dembélé, N; Brika, P G; Pearlman, E; Unnasch, T R

    2000-01-01

    The Onchocerciasis Control Programme in West Africa (OCP) has succeeded in eliminating blinding onchocerciasis as a public health problem throughout much of West Africa. The efforts of the OCP are now turning towards surveillance, with the goal of rapidly detecting and controlling outbreaks of infection in the onchocerciasis-free zone. With this goal in mind, cutaneous application of a solution of diethylcarbamazine (the DEC-patch test) was evaluated in 1996-99 as a method to detect patent Onchocerca volvulus infection in children and adolescents, a sentinel population for the detection of recrudescence. In an analysis of 1887 individuals in Côte d'Ivoire and Burkina Faso, the DEC-patch test produced prevalence estimates comparable to those obtained by skin snip. The sensitivity of the DEC-patch assay was marginally greater in children and adolescents than in adults, and was greater in individuals who had received prior Mectizan treatment. These data suggest that the DEC-patch test may be a useful tool for detecting recrudescence of O. volvulus infection in a sentinel population of children and young adults within the onchocerciasis-free zone created by the OCP.

  5. Experiences and Psychosocial Impact of West Africa Ebola Deployment on US Health Care Volunteers.

    PubMed

    Gershon, Robyn; Dernehl, Liza A; Nwankwo, Ezinne; Zhi, Qi; Qureshi, Kristine

    2016-09-21

     This qualitative study was designed to assess health care volunteers' experiences and psychosocial impacts associated with deployment to the West Africa Ebola epidemic. In 2015, using snowball sampling, 16 US health care volunteers who had recently returned from West Africa were recruited for this study. Semi-structured interviews were conducted to collect information associated with each phase of deployment (pre, peri, and post). Participants reported that they were motivated to volunteer because of a sense of responsibility and feelings of empathy and altruism. Immediately prior to deployment, most reported fear of contagion and death, as well as doubts regarding the adequacy of their training. Family members and close friends expressed high levels of concern regarding participants' decisions to volunteer. During the deployment, participants were fearful of exposure and reported feeling emotionally and physically exhausted. They also reported feeling frustrated by extreme resource limitations, poor management of the mission, lack of clearly defined roles and responsibilities, and inability to provide high quality care. Upon return home, participants felt a sense of isolation, depression, stigmatization, interpersonal difficulties, and extreme stress.  Preparedness of volunteers was suboptimal at each stage of deployment. All stakeholders, including volunteers, sponsoring organizations, government agencies, and professional organizations have a shared responsibility in ensuring that volunteers to medical missions are adequately prepared. This is especially critical for high risk deployments. Effective policies and practices need to be developed and implemented in order to protect the health and well-being of health care volunteers to the fullest extent possible.

  6. Establishment of a General Medicine Residency Training Program in Rural West Africa

    PubMed Central

    Drislane, Frank W.; Akpalu, Albert; Wegdam, Harry H.J.

    2014-01-01

    Ghana, a developing country in West Africa, has major medical burdens in taking care of a large population with limited resources. Its three medical schools produce more than 200 graduates per year, but most emigrate to developed lands after training. Ghana is working to educate and retain locally trained physicians, but it is difficult to get them to work in rural settings where the need is greatest. This article details the establishment of a General Medicine residency at a 150-bed hospital in rural Ghana. Early training comprises 6 months each in Medicine, Surgery, OB/GYN, and Pediatrics; the hospital in Techiman also has a Surgery residency. House officers choose the program for more hands-on experience than they can get in larger centers. They perform many tasks, including surgery, sooner and more independently than do residents in developed countries. The training program includes a morning report, clinical teaching rounds, and rotations on in-patient wards and in the Emergency Department and clinics. Teaching focuses on history, physical examination, good communication, and proper follow-up, with rigorous training in the OR and some clinical research projects pertinent to Ghana. Trainees work hard and learn from one another, from a dedicated faculty, and by evaluating and treating very sick patients. Ghana’s rural residencies offer rigorous and attractive training, but it is too soon to tell whether this will help stem the “brain drain” of young physicians out of West Africa. PMID:25191148

  7. Neogene cratonic erosion fluxes and landform evolution processes from regional regolith mapping (Burkina Faso, West Africa)

    NASA Astrophysics Data System (ADS)

    Grimaud, Jean-Louis; Chardon, Dominique; Metelka, Václav; Beauvais, Anicet; Bamba, Ousmane

    2015-07-01

    The regionally correlated and dated regolith-paleolandform sequence of Sub-Saharan West Africa offers a unique opportunity to constrain continental-scale regolith dynamics as the key part of the sediment routing system. In this study, a regolith mapping protocol is developed and applied at the scale of Southwestern Burkina Faso. Mapping combines field survey and remote sensing data to reconstruct the topography of the last pediplain that formed over West Africa in the Early and Mid-Miocene (24-11 Ma). The nature and preservation pattern of the pediplain are controlled by the spatial variation of bedrock lithology and are partitioned among large drainage basins. Quantification of pediplain dissection and drainage growth allows definition of a cratonic background denudation rate of 2 m/My and a minimum characteristic timescale of 20 Ma for shield resurfacing. These results may be used to simulate minimum export fluxes of drainage basins of constrained size over geological timescales. Background cratonic denudation results in a clastic export flux of ~ 4 t/km2/year, which is limited by low denudation efficiency of slope processes and correlatively high regolith storage capacity of tropical shields. These salient characteristics of shields' surface dynamics would tend to smooth the riverine export fluxes of shields through geological time.

  8. Nocturnal low-level clouds over southern West Africa analysed using high-resolution simulations

    NASA Astrophysics Data System (ADS)

    Adler, Bianca; Kalthoff, Norbert; Gantner, Leonhard

    2017-01-01

    We performed a high-resolution numerical simulation to study the development of extensive low-level clouds that frequently form over southern West Africa during the monsoon season. This study was made in preparation for a field campaign in 2016 within the Dynamics-aerosol-chemistry-cloud interactions in West Africa (DACCIWA) project and focuses on an area around the city of Savè in southern Benin. Nocturnal low-level clouds evolve a few hundred metres above the ground around the same level as a distinct low-level jet. Several processes are found to determine the spatio-temporal evolution of these clouds including (i) significant cooling of the nocturnal atmosphere caused by horizontal advection with the south-westerly monsoon flow during the first half of the night, (ii) vertical cold air advection due to gravity waves leading to clouds in the wave crests and (iii) enhanced convergence and upward motion upstream of existing clouds that trigger new clouds. The latter is caused by an upward shift of the low-level jet in cloudy areas leading to horizontal convergence in the lower part and to horizontal divergence in the upper part of the cloud layer. Although this single case study hardly allows for a generalisation of the processes found, the results added to the optimisation of the measurements strategy for the field campaign and the observations will be used to test the hypotheses for cloud formation resulting from this study.

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

    PubMed

    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.

  10. Mechanisms Linking Land Use and Regional Climate Changes in West Africa

    NASA Astrophysics Data System (ADS)

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

    2014-12-01

    Land use land cover change is an important driver for regional climate changes in West Africa due to the strong land-atmosphere coupling. On the other hand, land use is also strongly influenced by climate changes due to the primarily rain-fed agriculture in this region and the relatively low capacity to adapt. It is therefore important that projections for future climate changes or land use changes account for the impact of the feedback between land use and climate. Land use influences regional climate through several different pathways, including changes in surface biogeophysical properties (e.g., surface albedo, Bowen ratio, surface roughness) that have been widely studied, and changes in the dynamic properties of the land surface influencing dust emission. The relative importance of these two pathways is likely to be model dependent and region dependent. In this study the effects of these two pathways will be evaluated and compared, based on results from a modeling framework that includes a regional climate-vegetation model, a crop growth model, an agricultural economics model, and a land use allocation model. This will be conducted in the context of future land use and climate change projections, with the ultimate objective to assess how agricultural land use in West Africa may change driven by climate and socioeconomic changes, and how the resulting land use change may further modify regional climate in the future.

  11. Clinical manifestations of Waardenburg syndrome in a male adolescent in Mali, West Africa.

    PubMed

    Imperato, Pascal James; Imperato, Gavin H

    2015-02-01

    Waardenburg syndrome (WS) is a genetic disorder of which there are four distinct types. These four types are differentiated by the physical defects which they produce. Presented here is the case of a 13-year-old boy with WS Type I who was observed and physically assessed in Mali, West Africa in 1969. His physical findings included a bright blue coloring to the irises of the eyes, profound sensorineural deafness, mutism, dystopia canthorum (lateral displacement of the inner canthi of the eyes), broad nasal root, bushy eyebrows, and scaphoid deformities of the supraorbital portions of the frontal bone. Because family members were not available for interviews or physical examinations, it was not possible to determine if this patient was suffering from a congenital form of the disorder or from a spontaneous mutation. Given the patient's then location in a remote rural area of Mali where electricity was absent, it was not possible to perform additional diagnostic tests. The patient described here is the first with WS in Mali, West Africa to have been medically observed and evaluated and later documented in the medical literature. A second case of the syndrome in Mali was described in the medical literature in 2011 in an 18-month-old infant who did not have sensorineural hearing loss, but who did have a bilateral cleft lip. An historical overview of WS is presented along with details concerning the characteristics of the four types of the disorder.

  12. Development of a new gas-flaring emission dataset for southern West Africa

    NASA Astrophysics Data System (ADS)

    Deetz, Konrad; Vogel, Bernhard

    2017-04-01

    A new gas-flaring emission parameterization has been developed, which combines remote sensing observations using Visible Infrared Imaging Radiometer Suite (VIIRS) nighttime data with combustion equations. The parameterization has been applied to southern West Africa, including the Niger Delta as a region that is highly exposed to gas flaring. Two 2-month datasets for June-July 2014 and 2015 were created. The parameterization delivers emissions of CO, CO2, NO, NO2 and SO2. A flaring climatology for both time periods has been derived. The uncertainties owing to cloud cover, parameter selection, natural gas composition and the interannual differences are assessed. The largest uncertainties in the emission estimation are linked to the parameter selection. It can be shown that the flaring emissions in Nigeria have significantly decreased by 25 % from 2014 to 2015. Existing emission inventories were used for validation. CO2 emissions with the estimated uncertainty in parentheses of 2.7 (3. 6/0. 5) Tg yr-1 for 2014 and 2.0 (2. 7/0. 4) Tg yr-1 for 2015 were derived. Regarding the uncertainty range, the emission estimate is in the same order of magnitude compared to existing emission inventories with a tendency for underestimation. The deviations might be attributed to a shortage in information about the combustion efficiency within southern West Africa, the decreasing trend in gas flaring or inconsistent emission sector definitions. The parameterization source code is available as a package of R scripts.

  13. Overview of the DACCIWA ground-based field campaign in southern West Africa

    NASA Astrophysics Data System (ADS)

    Lohou, Fabienne; Kalthoff, Norbert; Brooks, Barbara; Jegede, Gbenga; Adler, Bianca; Ajao, Adewale; Ayoola, Muritala; Babić, Karmen; Bessardon, Geoffrey; Delon, Claire; Dione, Cheikh; Handwerker, Jan; Jambert, Corinne; Kohler, Martin; Lothon, Marie; Pedruzo-Bagazgoitia, Xabier; Smith, Victoria; Sunmonu, Lukman; Wieser, Andreas; Derrien, Solène

    2017-04-01

    During June and July 2016, a ground-based field campaign took place in southern West Africa within the framework of the Dynamics-aerosol-chemistry-cloud interactions in West Africa (DACCIWA) project. In the investigated region, extended low-level stratus clouds form very frequently during night-time and persist long into the following day influencing the diurnal cycle of the atmospheric boundary layer and, hence, the regional climate. The motivation for the measurements was to identify the meteorological controls on the whole process chain from the formation of nocturnal stratus clouds, via the daytime transition to convective clouds and the formation of deep precipitating clouds. During the measurement period, extensive remote sensing and in-situ measurements were performed at three supersites in Kumasi (Ghana), Savè (Benin) and Ile-Ife (Nigeria). The gathered observations included the energy-balance components at the Earth's surface, the mean and turbulent conditions in the nocturnal and daytime ABL as well as the de- and entrainment processes between the ABL and the free troposphere. The meteorological measurements were supplemented by aerosol and air-chemistry observations. We will give an overview of the conducted measurements including instrument availability and strategy during intensive observation periods.

  14. Gravity-driven structures and rift basin evolution: Rio Muni Basin, offshore equatorial West Africa

    SciTech Connect

    Turner, J.P.

    1995-08-01

    Offshore Equatorial Guinea, west Africa, gravity-driven nappes, more than 1 km thick and 15 km from head to toe, provide key evidence in reconstructing the late synrift: evolution of this part of the South Atlantic margin basin system. Furthermore, Aptian-Cenomanian carbonate and clastic rocks in the nappes` allochthonous hanging walls are attracting interest as a new exploration play in west Africa. The nappes exhibit a range of geometries that suggest they share many of the same deformation processes as thin-skin thrust and linked extensional fault systems. Not only are these structures significant in their own right, representing a rare example of gravity tectonics in the virtual absence of major halokinesis, but their presence may record an other-wise undetectable process active during the transition from a rift basin to a passive continental margin. A review of Equatorial Guinea in its pre-Atlantic configuration, alongside neighboring basins in Brazil (the Sergipe-Alagoas basin) and Gabon, suggests that gravity gliding was sustained by a relatively steep, westward paleoslope promoted by east-ward offset of the locus of thermal uplift from the rift basin (i.e., a simple shear model of basin formation). In contrast to gravity-driven structures in most postrift settings, the Equatorial Guinea nappes developed at the close of the Aptian-Albian synrift episode in response to a growing bathymetric deep caused by rapid subsidence outpacing restricted sedimentation.

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

    PubMed

    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.

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

    NASA Technical Reports Server (NTRS)

    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.

  17. Sociocultural aspects of risk to pregnant women during the 2013-2015 multinational Ebola virus outbreak in West Africa.

    PubMed

    Strong, Adrienne; Schwartz, David A

    2016-08-01

    Researchers reflect on sociocultural aspects of the Ebola outbreak in West Africa and critically analyze the epidemic's effects on pregnant mothers and their babies. We address structural inequalities contributing to poor maternal health in lower-income countries, while reflecting on how the Ebola outbreak highlights the still-marginalized role of pregnant women. Drawing on prior research in West and East Africa, we discuss health care providers' responses to risk of infection during maternity work under normal circumstances and in times of crisis. We end with recommendations for preventing such detrimental effects on the health of pregnant women in the case of another epidemic.

  18. Consultation-liaison psychiatry in a general hospital setting in west Africa.

    PubMed

    Aghanwa, H S; Morakinyo, O; Aina, O F

    1996-02-01

    This study examined the pattern of psychiatric consultation-liaison service in a West African general hospital setting over a period of five years. Cases seen were recorded in a register and later analysed. The rate of referral was found to be lower than those of Britain and USA. Most of the patients seen were young persons between the ages of 16 and 45 years. The predominant physical disorders complicated by psychopathology were infective disorders, neurological disorders, cardiovascular, and obstetric conditions. The commonest psychiatric syndromes encountered were acute brain syndrome, brief reactive psychosis, depressive disorder and dementia. A negative attitude towards patients with psychiatric co-morbidity was identified. Areas of improving consultation-liaison psychiatric services in West Africa are suggested.

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

    NASA Astrophysics Data System (ADS)

    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.

    PubMed

    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.

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

    PubMed

    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.

  2. A review of mangrove and coastal ecosystems in West Africa and their possible relationships

    NASA Astrophysics Data System (ADS)

    John, D. M.; Lawson, G. W.

    1990-11-01

    Mangrove forest, which in West Africa covers an area of over 27 000 km 2 of deltas, estuaries and lagoons, is intimately linked to the offshore coastal ecosystem. Regularly influenced and disturbed by seasonal freshwater and diurnal tidal flooding, it exhibits features of an immature ecosystem, namely low species diversity and high productivity. The excess organic production is exploited by many marine species especially fishes and crustaceans that enter the mangrove environment as juveniles and return to the sea as adults for reproductive purposes. The beneficial effects on marine fisheries of this net energy outflow are at risk from anthropogenic influences causing pollution or destruction of the mangrove ecosystem. Intense interdisciplinary work on this problem is in progress on the lagoons of the Ivory Coast but further research on other parts of the West African mangrove ecosystem, especially on the Niger delta, needs to be undertaken to provide the scientific basis for the proper management of this valuable natural resource.

  3. Sero-genetic studies on the Dama of South West Africa.

    PubMed

    Nurse, G T; Lane, A B; Jenkins, T

    1976-01-01

    The Dama of South West Africa are a Negroid people living as a reproductive isolate in the desert and semi-desert areas of the north-west of the country. Until recent times a large proportion of them were held in bondage by the Khoikhoi (Hottentot) Nama, while the rest lived as hunter-gatherers in the mountains. This study and the work of Knussmann and Knussmann indicate that they are a Negro people, which probably has been cut off over a period from contact with other Negroes. They have received very little genetic contribution from the Khoikhoi or the San (Bushmen). The results of this investigation of 24 blood genetic marker systems in a carefully selected random sample of Dama support these conclusions.

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

    PubMed Central

    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

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

    NASA Astrophysics Data System (ADS)

    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

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

    PubMed

    Sousa, João Dinis; Temudo, Marina Padrão; Hewlett, Barry Stephen; Camacho, Ricardo Jorge; Müller, Viktor; Vandamme, Anne-Mieke

    2016-01-01

    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. 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. 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 populations. Lack of MC in rural areas exposed to

  7. Kinematic structures, diabatic profiles, and precipitation systems in West Africa during summer 2006

    NASA Astrophysics Data System (ADS)

    Davis, Adam James

    This work uses a gridded analysis of radiosonde measurements obtained during AMMA and places those observations in the context of African Monsoon Multidisciplinary Analysis (AMMA) radar data and satellite rainfall estimates to examine the patterns of kinematic and diabatic quantities in West Africa relative to the summer monsoon phase, easterly wave disturbances, precipitation systems, and the diurnal cycle. Many unique aspects of West African weather compared to conditions elsewhere in the tropics are revealed by this study. The meridional transitions related to the West African monsoon comprise the predominant control on the location and intensity of precipitation at seasonal time scales, with variations in convective activity related to the Madden-Julian Oscillation contributing at 25 to 60 day periods. On shorter time scales of two to six days, easterly wave disturbances look to be the principal factor governing the timing of rainfall events, though especially persistent cold pools and residual cloudiness generated by thunderstorm systems also act as constraints on convective evolution on the days following a precipitation episode. One of the most distinctive traits of the study region in West Africa compared to other tropical areas is the particular prevalence of convective downdrafts, chiefly those associated with mesoscale zones of stratiform precipitation in thunderstorm complexes. These features, along with the gravity waves forced by their characteristic heating pattern, have an especially large influence on the time-mean atmospheric structure relative to the majority of the tropics. A comparison of the diabatic profiles from the AMMA dataset with those from other field projects indicates that the signals of both convective downdrafts and diurnal variations of the planetary boundary layer are much stronger in West Africa than in the previously studied regions. Beyond the mentioned differences, though, the AMMA profiles show resemblance to those from both

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

    NASA Astrophysics Data System (ADS)

    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

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

    NASA Astrophysics Data System (ADS)

    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.

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

    NASA Astrophysics Data System (ADS)

    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).

  11. Impact of dynamical regionalization on precipitation biases and teleconnections over West Africa

    NASA Astrophysics Data System (ADS)

    Gómara, Iñigo; Mohino, Elsa; Losada, Teresa; Domínguez, Marta; Suárez-Moreno, Roberto; Rodríguez-Fonseca, Belén

    2017-09-01

    West African societies are highly dependent on the West African Monsoon (WAM). Thus, a correct representation of the WAM in climate models is of paramount importance. In this article, the ability of 8 CMIP5 historical General Circulation Models (GCMs) and 4 CORDEX-Africa Regional Climate Models (RCMs) to characterize the WAM dynamics and variability is assessed for the period July-August-September 1979-2004. Simulations are compared with observations. Uncertainties in RCM performance and lateral boundary conditions are assessed individually. Results show that both GCMs and RCMs have trouble to simulate the northward migration of the Intertropical Convergence Zone in boreal summer. The greatest bias improvements are obtained after regionalization of the most inaccurate GCM simulations. To assess WAM variability, a Maximum Covariance Analysis is performed between Sea Surface Temperature and precipitation anomalies in observations, GCM and RCM simulations. The assessed variability patterns are: El Niño-Southern Oscillation (ENSO); the eastern Mediterranean (MED); and the Atlantic Equatorial Mode (EM). Evidence is given that regionalization of the ENSO-WAM teleconnection does not provide any added value. Unlike GCMs, RCMs are unable to precisely represent the ENSO impact on air subsidence over West Africa. Contrastingly, the simulation of the MED-WAM teleconnection is improved after regionalization. Humidity advection and convergence over the Sahel area are better simulated by RCMs. Finally, no robust conclusions can be determined for the EM-WAM teleconnection, which cannot be isolated for the 1979-2004 period. The novel results in this article will help to select the most appropriate RCM simulations to study WAM teleconnections.

  12. Evaluation of the COSMO-CLM high-resolution climate simulations over West Africa

    NASA Astrophysics Data System (ADS)

    Dieng, Diarra; Smiatek, Gerhard; Bliefernicht, Jan; Heinzeller, Dominikus; Sarr, A.; Gaye, A. T.; Kunstmann, Harald

    2017-02-01

    The evaluation of a high-resolution simulation at 0.11° (12 km) with the COnsortium for Small-scale MOdelling in CLimate Mode (CCLM) regional climate model, applied over West Africa, is presented. This simulation is nested in a CCLM run at resolution of 0.44°, driven with boundary forcing data from the ERA-Interim reanalysis, and covers the period from 1981 to 2010. The simulated temperature and precipitation are evaluated using three selected climate indices for temperature and eight indices for precipitation in five different regions against a new, daily precipitation climatology covering West Africa and against other state of the art climatologies. The obtained results indicate that CCLM is able to reproduce the observed major climate characteristics including the West African Monsoon within the range of comparable regional climate modeling evaluations studies, but substantial uncertainties remain, especially in the Sahel zone. The seasonal mean temperature bias for the rainy season from June to September ranges from -0.8°C to -1.1°C. The CCLM simulations also underestimate the observed precipitation with biases in precipitation reaching -10% in the high-resolution and -20% in the low-resolution model runs. CCLM extends the monsoon precipitation belt too far north, which results in an overestimation of precipitation in the Sahel zone of up to 60%. In the coastal zone, the precipitation is underestimated by up to -90%. These biases in precipitation amounts are associated with errors in the precipitation seasonality. The added value of the higher resolution of the nested run is reflected in a smaller bias in extreme precipitation statistics with respect to the reference data.

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

    NASA Technical Reports Server (NTRS)

    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.

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

    NASA Technical Reports Server (NTRS)

    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.

  15. The prevalence, awareness, and control of hypertension among workers in West Africa: a systematic review

    PubMed Central

    Bosu, William K.

    2015-01-01

    Background Interventions in workplace settings are considered to be cost-effective in preventing cardiovascular diseases. A systematic review was conducted to assess the prevalence of hypertension and the level of awareness and control among workers in West Africa. Design A systematic search for studies on formal and informal sector workers aged ≥15 years in West Africa published between 1980 and September 2014 was undertaken using the Ovid Medline, Embase, PubMed, and Google Scholar databases. Clinical and obstetric studies and studies that did not report prevalence were excluded. Data on study settings, characteristics of workers, blood pressure (BP) levels, prevalence of hypertension, and associated demographic factors were extracted. Results A total of 45 studies from six countries were identified involving 30,727 formal and informal sector workers. In 40 studies with a common definition of hypertension, the prevalence ranged from 12.0% among automobile garage workers to 68.9% among traditional chiefs. In 15 of these studies, the prevalence exceeded 30%. Typically sedentary workers such as traders, bank workers, civil servants, and chiefs were at high risk. Among health care workers, the prevalence ranged from 17.5 to 37.5%. The prevalence increased with age and was higher among males and workers with higher socio-economic status. Complications of hypertension, co-morbidities, and clustering of risk factors were common. The crude prevalence of hypertension increased progressively from 12.9% in studies published in the 1980s to 34.4% in those published in 2010–2014. The proportion of hypertensives who were previously aware of their diagnosis, were on treatment or had their BP controlled was 19.6–84.0%, 0–79.2%, and 0–12.7%, respectively. Hypertensive subjects, including health workers, rarely checked their BP except when they were ill. Conclusions There is a high prevalence of hypertension among West Africa's workforce, of which a significant

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

    PubMed Central

    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

  17. Malaria vector populations across ecological zones in Guinea Conakry and Mali, West Africa.

    PubMed

    Coulibaly, Boubacar; Kone, Raymond; Barry, Mamadou S; Emerson, Becky; Coulibaly, Mamadou B; Niare, Oumou; Beavogui, Abdoul H; Traore, Sekou F; Vernick, Kenneth D; Riehle, Michelle M

    2016-04-08

    Malaria remains a pervasive public health problem in sub-Saharan West Africa. Here mosquito vector populations were explored across four sites in Mali and the Republic of Guinea (Guinea Conakry). The study samples the major ecological zones of malaria-endemic regions in West Africa within a relatively small distance. Mosquito vectors were sampled from larval pools, adult indoor resting sites, and indoor and outdoor human-host seeking adults. Mosquitoes were collected at sites spanning 350 km that represented arid savannah, humid savannah, semi-forest and deep forest ecological zones, in areas where little was previously known about malaria vector populations. 1425 mosquito samples were analysed by molecular assays to determine species, genetic attributes, blood meal sources and Plasmodium infection status. Anopheles gambiae and Anopheles coluzzii were the major anophelines represented in all collections across the ecological zones, with A. coluzzii predominant in the arid savannah and A. gambiae in the more humid sites. The use of multiple collection methodologies across the sampling sites allows assessment of potential collection bias of the different methods. The L1014F kdr insecticide resistance mutation (kdr-w) is found at high frequency across all study sites. This mutation appears to have swept almost to fixation, from low frequencies 6 years earlier, despite the absence of widespread insecticide use for vector control. Rates of human feeding are very high across ecological zones, with only small fractions of animal derived blood meals in the arid and humid savannah. About 30 % of freshly blood-fed mosquitoes were positive for Plasmodium falciparum presence, while the rate of mosquitoes with established infections was an order of magnitude lower. The study represents detailed vector characterization from an understudied area in West Africa with endemic malaria transmission. The deep forest study site includes the epicenter of the 2014 Ebola virus epidemic

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

    NASA Astrophysics Data System (ADS)

    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

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

    PubMed

    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.

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

    ERIC Educational Resources Information Center

    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…

  1. The mineralogy of global magnetic anomalies. [rock magnetic signatures and MAGSAT geological, and gravity correlations in West Africa

    NASA Technical Reports Server (NTRS)

    Haggerty, S. E. (Principal Investigator)

    1982-01-01

    Problems with the Curie balance, which severely hindered the acquisition of data, were rectified. Chemical analytical activities are proceeding satisfactorily. The magnetization characteristics of metamorphic suites were analyzed and susceptibility data for a wide range of metamorphic and igneous rocks. These rock magnetic signatures are discussed as well as the relationships between geology, gravity and MAGSAT anomalies of West Africa.

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

    ERIC Educational Resources Information Center

    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…

  3. Training of School Teachers in West Africa: Remediation of Reading Difficulties through Training in Phonological Awareness and Letter Names

    ERIC Educational Resources Information Center

    Briquet-Duhazé, Sophie

    2014-01-01

    The training of teachers of West Africa is carried out by the Academy of Rouen (France) and organized around an annual training plan approved by the AEFE. Each trainer only supervises twenty teachers for 5 days. Teachers from eight countries (Mauritania, Cape Verde, Senegal, Gambia, Mali, Guinea, Côte d'Ivoire and Burkina Faso), come to Dakar for…

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

    ERIC Educational Resources Information Center

    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…

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

    ERIC Educational Resources Information Center

    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…

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

    USDA-ARS?s Scientific Manuscript database

    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...

  7. Determinants of Mean Blood Pressure and Hypertension among Workers in West Africa

    PubMed Central

    Bosu, William K.

    2016-01-01

    Background. This review was undertaken to estimate the mean blood pressure and evaluate its determinants as well as the determinants of hypertension among workers in West Africa. Methods. In a follow-up to an earlier study, a systematic search for articles published between 1980 and August 2015 was undertaken using major databases. Results. A total of 55 articles involving 34,919 different cadres of workers from six countries were retrieved. The mean systolic blood pressure (BP) ranged from 116.6 ± 1.3 mmHg to 151.7 ± 13.6 mmHg while the mean diastolic BP ranged from 69.6 ± 11.0 mmHg to 97.1 ± 9.1 mmHg. Population-wide prehypertension was common. The major determinants of mean BP and hypertension were similar and included male sex, older age group, higher socioeconomic status, obesity, alcohol consumption, plasma glucose, and sodium excretion. Ethnicity and educational level were inconsistently associated with hypertension. Workers at higher risk of cardiovascular event did not perceive themselves as such. Conclusion. The prevailing mean prehypertensive BP, low perception of risk, and clustering of risk factors call for interventions such as healthy diets, improved physical activity, and a favourable work environment. Successful models for improving the cardiovascular health of sedentary informal sector workers in Africa are urgently needed. PMID:26949543

  8. Public health professionals’ perceptions of mental health services in Equatorial Guinea, Central-West Africa

    PubMed Central

    Reuter, Peter Robert; McGinnis, Shannon Marcail; Reuter, Kim Eleanor

    2016-01-01

    Introduction Mental health disorders constitute 13% of global disease burden, the impacts of which are disproportionality felt in sub-Saharan Africa. Equatorial Guinea, located in Central-West Africa, has the highest per-capita investment in healthcare on the African continent, but only two studies have discussed mental health issues in the country and none of have examined the perspective of professionals working in the field. The purpose of this study was to gain a preliminary understanding of Equatoguinean health care professionals' perspectives on the mental health care system. Methods Nine adult participants (directors or program managers) were interviewed in July 2013 in Malabo, Equatorial Guinea from government agencies, aid organizations, hospitals, and pharmacies. Interviews were designed to collect broad information about the mental healthcare system in Equatorial Guinea including the professionals' perspectives and access to resources. This research was reviewed and approved by an ethical oversight committee. Results All individuals interviewed indicated that the mental health system does not currently meet the needs of the community. Professionals cited infrastructural capacity, stigmatization, and a lack of other resources (training programs, knowledgeable staff, medications, data) as key factors that limit the effectiveness of mental healthcare. Conclusion This study provides a preliminary understanding of the existing mental health care needs in the country, highlighting opportunities for enhanced healthcare services. PMID:28293352

  9. Public health professionals' perceptions of mental health services in Equatorial Guinea, Central-West Africa.

    PubMed

    Reuter, Peter Robert; McGinnis, Shannon Marcail; Reuter, Kim Eleanor

    2016-01-01

    Mental health disorders constitute 13% of global disease burden, the impacts of which are disproportionality felt in sub-Saharan Africa. Equatorial Guinea, located in Central-West Africa, has the highest per-capita investment in healthcare on the African continent, but only two studies have discussed mental health issues in the country and none of have examined the perspective of professionals working in the field. The purpose of this study was to gain a preliminary understanding of Equatoguinean health care professionals' perspectives on the mental health care system. Nine adult participants (directors or program managers) were interviewed in July 2013 in Malabo, Equatorial Guinea from government agencies, aid organizations, hospitals, and pharmacies. Interviews were designed to collect broad information about the mental healthcare system in Equatorial Guinea including the professionals' perspectives and access to resources. This research was reviewed and approved by an ethical oversight committee. All individuals interviewed indicated that the mental health system does not currently meet the needs of the community. Professionals cited infrastructural capacity, stigmatization, and a lack of other resources (training programs, knowledgeable staff, medications, data) as key factors that limit the effectiveness of mental healthcare. This study provides a preliminary understanding of the existing mental health care needs in the country, highlighting opportunities for enhanced healthcare services.

  10. The summertime tropospheric temperature over the Tibetan Plateau and precipitation over West Africa

    NASA Astrophysics Data System (ADS)

    Nan, S.; Zhao, P.

    2016-12-01

    Using monthly mean data from the European Centre for Medium-Range Weather Forecasts (ECMWF) Interim Re-Analysis (ERA-Interim) and precipitation from GPCP and CMAP, we investigate the relationship between summertime Tibetan thermal condition and precipitation over West Africa and the associated physical processes. When the Tibetan tropospheric temperature (TTT) increases (decreases) in the boreal summer, above- (below-) normal precipitation tends to appear over the Sahel. Associated with the increased TTT, tropospheric temperature increases at the mid-lower latitudes over 20°W-40°E, with the center at the middle latitudes. Thus, a meridional temperature gradient points to the lower latitudes from the mid latitudes over the Northern Africa. On the basis of the thermal wind balance, it will be accompanied by the vertical shear in geostrophic winds. The result in the study indicates the enhanced westerly (easterly) winds appear at the lower (upper) troposphere over the Sahel associated with the increased TTT. Meanwhile, the zonal thermal wind anomalies calculated by the meridional temperature gradient anomalies associated with the increased TTT through the thermal wind equation are negative in the Sahel, consistent with the enhanced westerly monsoon flow at the lower troposphere and tropical easterly jet (TEJ) at the upper troposphere over the Sahel. Thus, the enhanced low-level westerly monsoon flow corresponding to the increased TTT may be explained by the thermal wind relation. And, it takes more water moist into the Sahel and results in the increased precipitation.

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

    PubMed

    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 < beta-endosulfan < deltamethrin). Soil dissipation was considerably slower than dissipation from plant surfaces with half-lives ranging from 3 (diazinon) to 74 d (total endosulfan), but persistence of pesticides in soil was still reduced compared to temperate climates. Nevertheless, for deltamethrin and endosulfan, a tendency for mid-term accumulation in soil upon repeated applications was observed. The soil and plant surface concentrations of the metabolite endosulfan sulfate increased during the entire trial period, indicating that this compound is a potential long-term pollutant even in tropical environments.

  12. Sowing the Seeds of Strategic Success across West Africa: Propagating the state partnership program to shape the security environment

    DTIC Science & Technology

    2017-06-09

    within statutory limits. The overcoming of obstacles and resultant success of the RAF was first documented during 30 the First Infantry Division’s...SOWING THE SEEDS OF STRATEGIC SUCCESS ACROSS WEST AFRICA: PROPAGATING THE STATE PARTNERSHIP PROGRAM TO SHAPE THE SECURITY ENVIRONMENT...TYPE Master’s Thesis 3. DATES COVERED (From - To) AUG 2016 – JUNE 2017 4. TITLE AND SUBTITLE Sowing the Seeds of Strategic Success Across West

  13. Remote sensing experiment in West Africa. [drought effects on desert agriculture and vegetation in Niger

    NASA Technical Reports Server (NTRS)

    Macleod, N. H.

    1974-01-01

    There are substantial needs of the Sahelien Zone to detail the state of regional agricultural resources in the face of a sixth year of serious drought conditions. While most of the work has been done in the Republic of Niger, the principles which have emerged from the analysis seem to be applicable to much of the Sahel. The discussion relates to quite specific rehabilitation and development initiations under consideration in Niger which are based in part upon direct analysis of ERTS imagery of the country, in part on field surveys and on discussions with Nigerian officials and technicians. Again, because the entire Sahelien Zone (including Niger) has large zones of similar ecologic characteristics, modificiations of the approaches suggested for Niger are applicable to the solution of rehabilitation of the desert, the savannah and the woodlands of West Africa in general.

  14. Climate forecasts in disaster management: Red Cross flood operations in West Africa, 2008.

    PubMed

    Braman, Lisette Martine; van Aalst, Maarten Krispijn; Mason, Simon J; Suarez, Pablo; Ait-Chellouche, Youcef; Tall, Arame

    2013-01-01

    In 2008, the International Federation of Red Cross and Red Crescent Societies (IFRC) used a seasonal forecast for West Africa for the first time to implement an Early Warning, Early Action strategy for enhanced flood preparedness and response. Interviews with disaster managers suggest that this approach improved their capacity and response. Relief supplies reached flood victims within days, as opposed to weeks in previous years, thereby preventing further loss of life, illness, and setbacks to livelihoods, as well as augmenting the efficiency of resource use. This case demonstrates the potential benefits to be realised from the use of medium-to-long-range forecasts in disaster management, especially in the context of potential increases in extreme weather and climate-related events due to climate variability and change. However, harnessing the full potential of these forecasts will require continued effort and collaboration among disaster managers, climate service providers, and major humanitarian donors.

  15. Perspectives on West Africa Ebola Virus Disease Outbreak, 2013-2016

    DOE PAGES

    Spengler, Jessica R.; Ervin, Elizabeth D.; Towner, Jonathan S.; ...

    2016-06-01

    The variety of factors that contributed to the initial undetected spread of Ebola virus disease in West Africa during 2013-2016 and the difficulty controlling the outbreak once the etiology was identified highlight priorities for disease prevention, detection, and response. These factors include occurrence in a region recovering from civil instability and lacking experience with Ebola response; inadequate surveillance, recognition of suspected cases, and Ebola diagnosis; mobile populations and extensive urban transmission; and the community's insufficient general understanding about the disease. The magnitude of the outbreak was not attributable to a substantial change of the virus. Finally, continued efforts during themore » outbreak and in preparation for future outbreak response should involve identifying the reservoir, improving in-country detection and response capacity, conducting survivor studies and supporting survivors, engaging in culturally appropriate public education and risk communication, building productive interagency relationships, and continuing support for basic research.« less

  16. Perspectives on West Africa Ebola Virus Disease Outbreak, 2013-2016

    SciTech Connect

    Spengler, Jessica R.; Ervin, Elizabeth D.; Towner, Jonathan S.; Rollin, Pierre E.; Nichol, Stuart T.

    2016-06-01

    The variety of factors that contributed to the initial undetected spread of Ebola virus disease in West Africa during 2013-2016 and the difficulty controlling the outbreak once the etiology was identified highlight priorities for disease prevention, detection, and response. These factors include occurrence in a region recovering from civil instability and lacking experience with Ebola response; inadequate surveillance, recognition of suspected cases, and Ebola diagnosis; mobile populations and extensive urban transmission; and the community's insufficient general understanding about the disease. The magnitude of the outbreak was not attributable to a substantial change of the virus. Finally, continued efforts during the outbreak and in preparation for future outbreak response should involve identifying the reservoir, improving in-country detection and response capacity, conducting survivor studies and supporting survivors, engaging in culturally appropriate public education and risk communication, building productive interagency relationships, and continuing support for basic research.

  17. Not just malaria: Mary Slessor (1848-1915) and other Victorian missionaries in West Africa.

    PubMed

    Hardage, Jeanette

    2006-11-01

    Fear of 'fever' was uppermost in the minds of many travellers to West Africa in Victorian times. 'Not just malaria...' chronicles attitudes, treatments and discoveries regarding malaria from the time of David Livingstone through the early 20th century. Missionaries often found themselves in the position of serving as untrained doctors and nurses among the people they went to evangelize. In addition, they suffered from the same maladies as the people did, and many died from malaria or other afflictions. Mary Slessor arrived in Calabar, in what is now southeastern Nigeria, to serve with the Scottish Presbyterian Mission in 1876. With only a few furloughs, she remained there until her death in 1915. The article relates instances of the illnesses and injuries she treated as well as those she suffered herself. She is remembered in Nigeria with statues and, along with David Livingstone, is one of Scotland's best-known missionary figures.

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

    NASA Astrophysics Data System (ADS)

    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.

  19. Continued Transmission of Zika Virus in Humans in West Africa, 1992-2016.

    PubMed

    Herrera, Bobby Brooke; Chang, Charlotte A; Hamel, Donald J; Mboup, Souleymane; Ndiaye, Daouda; Imade, Godwin; Okpokwu, Jonathan; Agbaji, Oche; Bei, Amy K; Kanki, Phyllis J

    2017-05-15

    First identified in 1947 in Uganda, Zika virus (ZIKV) has remained largely unstudied until the recent outbreak in Latin America. This study aimed to measure the prevalence of ZIKV in febrile patients in Senegal and Nigeria in samples collected from 1992 to 2016. The seroprevalence of ZIKV was 6.2% based on ZIKV immunoglobulin M and negative for dengue reactivity. ZIKV envelope was amplified from 4 samples. Phylogenetic analysis showed that the ZIKVs belonged to the African lineage, grouping with either the Nigerian or MR766 sublineages. This study provides evidence that ZIKV has been silently circulating in West Africa for 2 decades. © The Author 2017. Published by Oxford University Press for the Infectious Diseases Society of America. All rights reserved. For permissions, e-mail: journals.permissions@oup.com.

  20. Perspectives on West Africa Ebola Virus Disease Outbreak, 2013–2016

    PubMed Central

    Spengler, Jessica R.; Ervin, Elizabeth D.; Towner, Jonathan S.; Rollin, Pierre E.

    2016-01-01

    The variety of factors that contributed to the initial undetected spread of Ebola virus disease in West Africa during 2013–2016 and the difficulty controlling the outbreak once the etiology was identified highlight priorities for disease prevention, detection, and response. These factors include occurrence in a region recovering from civil instability and lacking experience with Ebola response; inadequate surveillance, recognition of suspected cases, and Ebola diagnosis; mobile populations and extensive urban transmission; and the community’s insufficient general understanding about the disease. The magnitude of the outbreak was not attributable to a substantial change of the virus. Continued efforts during the outbreak and in preparation for future outbreak response should involve identifying the reservoir, improving in-country detection and response capacity, conducting survivor studies and supporting survivors, engaging in culturally appropriate public education and risk communication, building productive interagency relationships, and continuing support for basic research. PMID:27070842

  1. Assessment of vaccination coverage, vaccination scar rates, and smallpox scarring in five areas of West Africa*

    PubMed Central

    Henderson, Ralph H.; Davis, Hillard; Eddins, Donald L.; Foege, William H.

    1973-01-01

    In 1966, nineteen countries of West and Central Africa began a regional smallpox eradication and measles control programme in cooperation with the World Health Organization. This paper summarizes sample survey data collected to assess the results of the programme in Northern Nigeria (Sokoto and Katsina Provinces), Western Nigeria, Niger, Dahomey, and Togo. These data indicate that the programme, which used mass vaccination campaigns based on a collecting-point strategy, was generally successful in reaching a high proportion of the population. Analysis of vaccination coverage and vaccination scar rates by age underlined the importance to the programme of newborn children who accumulate rapidly following the mass campaign. Of all persons without vaccination scars at the time of the surveys, 34.4% were under 5 years of age; in the absence of a maintenance programme, this figure would rise to 40% after 1 year. PMID:4541684

  2. Vegetation Change in West Africa as Assessed by Surface-Based and Satellite Observations

    NASA Astrophysics Data System (ADS)

    States, J. A.; Nicholson, S. E.

    2004-12-01

    The semi-arid Sahel of West Africa has experienced a remarkable change of climate over the last century. Long-term means of precipitation for 30 year periods have declined by 30% to 50% between 1931-60 and 1968-97. During this time there has been anecdotal evidence of major shifts in the vegetation zones. We have attempted to document these shifts by using maps and transcript studies from the 1950s to reconstruct the vegetation patterns that prevailed earlier in the century. AVHRR and MODIS have been used to determine vegetation classes and other characteristics for the more recent decades. The climatic variables that are associated with various types are assessed. A climate/vegetation analysis has been carried out for both the wetter conditions earlier in the century and for the recent dry decades.

  3. Rift Valley fever in West Africa: the role of space in endemicity.

    PubMed

    Favier, Charly; Chalvet-Monfray, Karine; Sabatier, Philippe; Lancelot, Renaud; Fontenille, Didier; Dubois, Marc A

    2006-12-01

    Rift Valley fever is an endemic vector-borne disease in West Africa, which mainly affects domestic ruminants and occasionally humans. The aetiological mechanisms of its endemicity remain under debate. We used a simple spatially explicit model to assess the possibility of endemicity without wild animals providing a permanent virus reservoir. Our model takes into account the vertical transmission in some mosquito species, the rainfall-driven emergence of their eggs and local and distant contacts because of herd migration. Endemicity without such a permanent virus reservoir would be impossible in a single site except when there is a strictly periodic rainfall pattern; but it would be possible when there are herd movements and sufficient inter-site variability in rainfall, which drives mosquito emergence.

  4. Satellite data transmission and hydrological forecasting in the fight against Onchocerciasis in west Africa

    NASA Astrophysics Data System (ADS)

    Servat, Eric; Lapetite, Jean-Marc; Bader, Jean-Claude; Boyer, Jean-Francois

    1990-09-01

    Onchocerciasis, or river blindness, is an endemic disease which causes great hardship in west Africa. Within the World Health Organization's Onchocerciasis Control Program (WHO/OCP), reliable data on the discharge of the watercourses have been obtained by using remote satellite transmission. These data are necessary to calculate how much insecticide should be introduced into the rivers. A description of the equipment and its use is followed by an initial report covering the functioning of the equipment, its efficiency and the economies attained. The improvement in the resulting treatment and the reduction in the running costs of the programme are discussed. Software for forecasting the discharge over different time intervals was developed by ORSTOM at the request of the OCP. The different functions of this software (PERLES) are described. In conclusion, the advantages of remote transmission techniques for operational hydrology in general are discussed (flood warning systems, hydrological networks, etc.).

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

    NASA Astrophysics Data System (ADS)

    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.

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

    PubMed Central

    Dicko, Fatoumata; Desmonde, Sophie; Koumakpai, Sikiratou; Dior-Mbodj, Hélène; Kouéta, Fla; Baeta, Novisi; Koné, Niaboula; Akakpo, Jocelyn; Sy, Haby Signate; Ye, Diarra; Renner, Lorna; Lewden, Charlotte; Leroy, Valériane

    2014-01-01

    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. PMID:24763078

  7. « Younger-Dryas / African Humid Period »: a notable climatic transition over West Africa

    NASA Astrophysics Data System (ADS)

    Skonieczny, C.; Bory, A. J.; Bout-Roumazeilles, V.; Malaizé, B.; Grousset, F. E.; Abouchami, W.; Galer, S. J.; Francois, R. H.

    2013-05-01

    Every year, several hundreds teragrams of dust are emitted from the Sahara and Sahel regions. These mineral particles sensitively track variations in atmospheric circulation and continental aridity. Sediments of the Northeastern Atlantic Tropical Ocean (NEATO) are fed by this intense dust supply and comprise unique long-term archives of past dust emissions. Past modifications of dust characteristics in these sedimentary archives can provide precious information on changes in environmental conditions in source areas (aridity, weathering), as well as on changes in the characteristics of their atmospheric transport (pathways and strength). Over Africa, gradual increases in local insolation due to changes in the Earth's orbit are accompanied by a migration of the precipitation monsoon-system (associated with the InterTropical Convergence Zone, ITCZ) toward the North. This displacement leads to decrease in West African mineral dust emission. Consequently, Saharan and Sahelian dust deposited in the NEATO sedimentary archives represent an exceptional opportunity to document the environmental and climatic changes that have taken place in West Africa throughout the Quaternary and beyond (Rea, 1994). Here we document changes in the terrigenous supplies to the NETAO throughout the last deglaciation using the marine sediment core MD03-2705 located off Mauritania (18°05N; 21°09W; 3085m water depth) and retrieved from a bathymetric dome, 300 meters above the surrounding seafloor. Considering this particular environmental setting, the terrigenous fraction in this record is assumed to be predominantly of aeolian origin. Multi-proxy analyses of the carbonate-free fraction of the sediment were carried-out, including dust fluxes, grain-size, clay mineralogy and geochemical measurements (major and trace elements as well as Sr & Nd isotopes). We will discuss the most significant changes recorded over the studied period: levels dated from the Younger Dryas and the subsequent African

  8. Secondary organic aerosol from biogenic VOCs over West Africa during AMMA

    NASA Astrophysics Data System (ADS)

    Capes, G.; Murphy, J. G.; Reeves, C. E.; McQuaid, J. B.; Hamilton, J. F.; Hopkins, J. R.; Crosier, J.; Williams, P. I.; Coe, H.

    2009-06-01

    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 1.07 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 broadly in agreement with global model predictions based on partitioning schemes, although there are large uncertainties associated with such estimates. In contrast our own calculations based on aerosol yields from isoprene and monoterpenes during chamber studies under represent the OM measured in this region on a comparable scale to the under representations of OM by predictive models in the mid latitudes. As global models rely on similar yield calculations in their global estimates, as our calculations this points to further systematic differences between global model estimates and measurements of SOA, most likely caused by use of incorrect BVOC emission rates. The under predictions of OM by our calculations and those in the mid latitudes employ yields extrapolated from chamber data obtained at higher mass concentrations - more recent yield data for α-pinene obtained at ambient concentrations in a flow through chamber (Shilling et al., 2008) show considerably better agreement with our data.

  9. Climatic and Human Influence on Tropical Forest Degradation in West Africa

    NASA Astrophysics Data System (ADS)

    Liu, Z., Sr.; Wimberly, M. C.; Dwomoh, F. K.

    2015-12-01

    The Upper Guinean Forests of West Africa encompass one of most fragmented and endangered tropical forest ecosystems on earth. However, relatively little is known about the extent and causes of forest degradation in this heavily human affected region. We used the tasseled cap wetness (TCW) index to detect forest degradation using dry-season imagery from 2001 to 2015. TCW was calculated from MODIS (or Moderate Resolution Imaging Spectroradiometer) Nadir BRDF-Adjusted Reflectance (NBAR) at 500 meter resolution. The TCW index was compared with field data and high-resolution imagery and was found to have a strong relationship with different level of forest degradation, with lower TCW index values indicating higher levels of degradation. Mann-Kendall tests were used to detect the monotonic decreases in TCW index. Results indicated that about 12.9% of tropical forest in West Africa has been degraded during past 15 years, and most of these areas were located in isolated forest patches and on the periphery of intact forest. The boosted regression tree (BRT) method was then used to assess the influence of climate and human influence on forest degradation. BRT analysis indicated that climatic variations, human activities, and their interactions were important contributors to forest degradation. Major drivers of forest degradation included distance to cropland, rainfall trend, and rate of population growth.. Our results show that times series of coarse-resolution MODIS imagery can be used for broad-scale assessment of tropical forest degradation, and human activities need to be taken into account when assessing potential forest responses to climate change in this region.

  10. Evaporation from cultivated and semi-wild Sudanian Savanna in west Africa

    NASA Astrophysics Data System (ADS)

    Ceperley, Natalie C.; Mande, Theophile; van de Giesen, Nick; Tyler, Scott; Yacouba, Hamma; Parlange, Marc B.

    2017-08-01

    Rain-fed farming is the primary livelihood of semi-arid west Africa. Changes in land cover have the potential to affect precipitation, the critical resource for production. Turbulent flux measurements from two eddy-covariance towers and additional observations from a dense network of small, wireless meteorological stations combine to relate land cover (savanna forest and agriculture) to evaporation in a small (3.5 km2) catchment in Burkina Faso, west Africa. We observe larger sensible and latent heat fluxes over the savanna forest in the headwater area relative to the agricultural section of the watershed all year. Higher fluxes above the savanna forest are attributed to the greater number of exposed rocks and trees and the higher productivity of the forest compared to rain-fed, hand-farmed agricultural fields. Vegetation cover and soil moisture are found to be primary controls of the evaporative fraction. Satellite-derived vegetation index (NDVI) and soil moisture are determined to be good predictors of evaporative fraction, as indicators of the physical basis of evaporation. Our measurements provide an estimator that can be used to derive evaporative fraction when only NDVI is available. Such large-scale estimates of evaporative fraction from remotely sensed data are valuable where ground-based measurements are lacking, which is the case across the African continent and many other semi-arid areas. Evaporative fraction estimates can be combined, for example, with sensible heat from measurements of temperature variance, to provide an estimate of evaporation when only minimal meteorological measurements are available in remote regions of the world. These findings reinforce local cultural beliefs of the importance of forest fragments for climate regulation and may provide support to local decision makers and rural farmers in the maintenance of the forest areas.

  11. How influences on teenage smoking reflect gender and society in Mali, West Africa

    PubMed Central

    Kirk, Anna

    2012-01-01

    Objectives To provide further understanding and discussion on the influences on smoking in young people in Mali. Design A generic qualitative methodological approach was used following Caelli's generic principles. Six focus group discussions were conducted with a total of 31 participants followed by two semi-structured interviews. A reflexive account was kept to record development in the researcher's theoretical position Setting The setting was recreational areas of Bamako, capital city of Mali, West Africa. Participants Participants aged 13–15 years were recruited opportunistically in a recreational area of Bamako. Mainoutcome measures To develop further understanding of the influences of teenage smoking in Mali, West Africa. Results Five main categories that explained influences on youth smoking emerged: knowledge and awareness of smoking; associations with smoking; influential people; key messages in Malian society; and access to tobacco. The results showed that influences were complex and interwoven, notable gender differences were revealed, and the role of elder members of the community proved decisive in participants' smoking experiences. Participants described vague knowledge of the impact on health of smoking and reported trying smoking from an early age. Often contact with smoking was through elders and being sent to buy and sometimes light cigarettes for them. Associations with smoking were influenced by gender with smoking more desirable for boys than girls. Conclusions Any approach to preventing smoking initiation in young people requires an understanding of the social influences and pressures on young people. A tobacco control strategy is required to look at all areas of influence on smoking behaviours. Different needs should also account for the differing characteristics and perceptions of specific population groups. PMID:22299069

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

    NASA Astrophysics Data System (ADS)

    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. Role of the biosphere in the mid-Holocene climate of West Africa

    NASA Astrophysics Data System (ADS)

    Irizarry-Ortiz, Michelle M.; Wang, Guiling; Eltahir, Elfatih A. B.

    2003-01-01

    In previous studies, a zonally symmetric, synchronously coupled biosphere-atmosphere model (ZonalBAM), which includes explicit representation of ecosystem dynamics, has been developed and validated based on current conditions over the region of West Africa. Here, we use ZonalBAM to study the response of the coupled biosphere-atmosphere system to changes in the Earth's orbital forcing during the Middle Holocene (6K yrs BP) and the relative contribution of vegetation feedbacks. Simulations in which vegetation conditions were fixed to the current distribution, show that an orbitally induced increased seasonality in insolation for the Middle Holocene, by itself, results in a 1.1° northward shift in the location of the southern margin of the Sahara as compared to current solar forcings. When vegetation is allowed to be dynamic, a 2.4° northward shift is simulated. However, when dynamic vegetation is initialized to palaeovegetation, a 5.1° northward shift is simulated, bringing results more consistent with palaeoevidence. Based on previous studies on the role of the gradient of moist static energy on the dynamics of large-scale tropical circulations, a mechanism for the enhancement of the summer monsoon circulation has been developed. Our results suggest that multiple equilibria could have coexisted over the region of West Africa during the Middle Holocene. Furthermore, based on previous studies on the current climate over the region, we hypothesize that transitions between the different equilibria could have taken place during the Middle Holocene causing the southern desert margin to migrate between 18.1°N and 21.4°N and shaping climate variability.

  14. Experiences and Psychosocial Impact of West Africa Ebola Deployment on US Health Care Volunteers

    PubMed Central

    Gershon, Robyn; Dernehl, Liza A.; Nwankwo, Ezinne; Zhi, Qi; Qureshi, Kristine

    2016-01-01

    Background: This qualitative study was designed to assess health care volunteers’ experiences and psychosocial impacts associated with deployment to the West Africa Ebola epidemic. Methods: In 2015, using snowball sampling, 16 US health care volunteers who had recently returned from West Africa were recruited for this study. Semi-structured interviews were conducted to collect information associated with each phase of deployment (pre, peri, and post). Results: Participants reported that they were motivated to volunteer because of a sense of responsibility and feelings of empathy and altruism. Immediately prior to deployment, most reported fear of contagion and death, as well as doubts regarding the adequacy of their training. Family members and close friends expressed high levels of concern regarding participants’ decisions to volunteer. During the deployment, participants were fearful of exposure and reported feeling emotionally and physically exhausted. They also reported feeling frustrated by extreme resource limitations, poor management of the mission, lack of clearly defined roles and responsibilities, and inability to provide high quality care. Upon return home, participants felt a sense of isolation, depression, stigmatization, interpersonal difficulties, and extreme stress. Conclusion: Preparedness of volunteers was suboptimal at each stage of deployment. All stakeholders, including volunteers, sponsoring organizations, government agencies, and professional organizations have a shared responsibility in ensuring that volunteers to medical missions are adequately prepared. This is especially critical for high risk deployments. Effective policies and practices need to be developed and implemented in order to protect the health and well-being of health care volunteers to the fullest extent possible. PMID:27803840

  15. Using CHIRPS Rainfall Dataset to detect rainfall trends in West Africa

    NASA Astrophysics Data System (ADS)

    Blakeley, S. L.; Husak, G. J.

    2016-12-01

    In West Africa, agriculture is often rain-fed, subjecting agricultural productivity and food availability to climate variability. Agricultural conditions will change as warming temperatures increase evaporative demand, and with a growing population dependent on the food supply, farmers will become more reliant on improved adaptation strategies. Development of such adaptation strategies will need to consider West African rainfall trends to remain relevant in a changing climate. Here, using the CHIRPS rainfall product (provided by the Climate Hazards Group at UC Santa Barbara), I examine trends in West African rainfall variability. My analysis will focus on seasonal rainfall totals, the structure of the rainy season, and the distribution of rainfall. I then use farmer-identified drought years to take an in-depth analysis of intra-seasonal rainfall irregularities. I will also examine other datasets such as potential evapotranspiration (PET) data, other remotely sensed rainfall data, rain gauge data in specific locations, and remotely sensed vegetation data. Farmer bad year data will also be used to isolate "bad" year markers in these additional datasets to provide benchmarks for identification in the future of problematic rainy seasons.

  16. Etiology of urethral discharge in West Africa: the role of Mycoplasma genitalium and Trichomonas vaginalis.

    PubMed Central

    Pépin, J.; Sobéla, F.; Deslandes, S.; Alary, M.; Wegner, K.; Khonde, N.; Kintin, F.; Kamuragiye, A.; Sylla, M.; Zerbo, P. J.; Baganizi, E.; Koné, A.; Kane, F.; Mâsse, B.; Viens, P.; Frost, E.

    2001-01-01

    OBJECTIVE: To determine the etiological role of pathogens other than Neisseria gonorrhoeae and Chlamydia trachomatis in urethral discharge in West African men. METHODS: Urethral swabs were obtained from 659 male patients presenting with urethral discharge in 72 primary health care facilities in seven West African countries, and in 339 controls presenting for complaints unrelated to the genitourinary tract. Polymerase chain reaction analysis was used to detect the presence of N. gonorrhoeae, C. trachomatis, Trichomonas vaginalis, Mycoplasma genitalium, and Ureaplasma urealyticum. FINDINGS: N. gonorrhoeae, T. vaginalis, C. trachomatis, and M. genitalium--but not U. urealyticum--were found more frequently in men with urethral discharge than in asymptomatic controls, being present in 61.9%, 13.8%, 13.4% and 10.0%, respectively, of cases of urethral discharge. Multiple infections were common. Among patients with gonococcal infection, T. vaginalis was as frequent a coinfection as C. trachomatis. M. genitalium, T. vaginalis, and C. trachomatis caused a similar clinical syndrome to that associated with gonococcal infection, but with a less severe urethral discharge. CONCLUSIONS: M. genitalium and T. vaginalis are important etiological agents of urethral discharge in West Africa. The frequent occurrence of multiple infections with any combination of four pathogens strongly supports the syndromic approach. The optimal use of metronidazole in flowcharts for the syndromic management of urethral discharge needs to be explored in therapeutic trials. PMID:11242818

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

    NASA Astrophysics Data System (ADS)

    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

  18. Cost-Effectiveness of Antivenoms for Snakebite Envenoming in 16 Countries in West Africa

    PubMed Central

    Hamza, Muhammad; Idris, Maryam A.; Maiyaki, Musa B.; Lamorde, Mohammed; Chippaux, Jean-Philippe; Warrell, David A.; Kuznik, Andreas; Habib, Abdulrazaq G.

    2016-01-01

    Background Snakebite poisoning is a significant medical problem in agricultural societies in Sub Saharan Africa. Antivenom (AV) is the standard treatment, and we assessed the cost-effectiveness of making it available in 16 countries in West Africa. Methods We determined the cost-effectiveness of AV based on a decision-tree model from a public payer perspective. Specific AVs included in the model were Antivipmyn, FAV Afrique, EchiTab-G and EchiTab-Plus. We derived inputs from the literature which included: type of snakes causing bites (carpet viper (Echis species)/non-carpet viper), AV effectiveness against death, mortality without AV, probability of Early Adverse Reactions (EAR), likelihood of death from EAR, average age at envenomation in years, anticipated remaining life span and likelihood of amputation. Costs incurred by the victims include: costs of confirming and evaluating envenomation, AV acquisition, routine care, AV transportation logistics, hospital admission and related transportation costs, management of AV EAR compared to the alternative of free snakebite care with ineffective or no AV. Incremental Cost Effectiveness Ratios (ICERs) were assessed as the cost per death averted and the cost per Disability-Adjusted-Life-Years (DALY) averted. Probabilistic Sensitivity Analyses (PSA) using Monte Carlo simulations were used to obtain 95% Confidence Intervals of ICERs. Results The cost/death averted for the 16 countries of interest ranged from $1,997 in Guinea Bissau to $6,205 for Liberia and Sierra Leone. The cost/DALY averted ranged from $83 (95% Confidence Interval: $36-$240) for Benin Republic to $281 ($159–457) for Sierra-Leone. In all cases, the base-case cost/DALY averted estimate fell below the commonly accepted threshold of one time per capita GDP, suggesting that AV is highly cost-effective for the treatment of snakebite in all 16 WA countries. The findings were consistent even with variations of inputs in 1—way sensitivity analyses. In addition

  19. Crude childhood vaccination coverage in West Africa: Trends and predictors of completeness.

    PubMed

    Kazungu, Jacob S; Adetifa, Ifedayo M O

    2017-02-15

    Background: Africa has the lowest childhood vaccination coverage worldwide. If the full benefits of childhood vaccination programmes are to be enjoyed in sub-Saharan Africa, all countries need to improve on vaccine delivery to achieve and sustain high coverage. In this paper, we review trends in vaccination coverage, dropouts between vaccine doses and explored the country-specific predictors of complete vaccination in West Africa.  Methods: We utilized datasets from the Demographic and Health Surveys Program, available for Benin, Burkina Faso, The Gambia, Ghana, Guinea, Cote d'Ivoire, Liberia, Mali, Niger, Nigeria, Senegal, Sierra Leone and Togo, to obtain coverage for Bacillus Calmette-Guerin, polio, measles, and diphtheria, pertussis and tetanus (DPT) vaccines in children aged 12 - 23 months. We also calculated the DPT1-to-DPT3 and DPT1-to-measles dropouts, and proportions of the fully immunised child (FIC). Factors predictive of FIC were explored using Chi-squared tests and multivariable logistic regression.  Results: Overall, there was a trend of increasing vaccination coverage. The proportion of FIC varied significantly by country (range 24.1-81.4%, mean 49%). DPT1-to-DPT3 dropout was high (range 5.1% -33.9%, mean 16.3%). Similarly, DPT1-measles dropout exceeded 10% in all but four countries. Although no single risk factor was consistently associated with FIC across these countries, maternal education, delivery in a health facility, possessing a vaccine card and a recent post delivery visit to a health facility were the key predictors of complete vaccination.  Conclusions: The low numbers of fully immunised children and high dropout between vaccine doses highlights weaknesses and the need to strengthen the healthcare and routine immunization delivery systems in this region. Country-specific correlates of complete vaccination should be explored further to identify interventions required to increase vaccination coverage. Despite the promise of an increasing

  20. Hybrid Gravimetry for the Monitoring of Water Storage Changes in the Critical Zone of West Africa

    NASA Astrophysics Data System (ADS)

    Hector, B.; Hinderer, J.; Séguis, L.; Calvo, M.; Pfeffer, J.

    2015-12-01

    Time-lapse gravimetry is known to be a powerful tool to monitor mass redistributions near the Earth's surface and hence is of interest in various fields (volcanology, hydrology, glaciology, geothermics, C02 sequestration). Hybrid gravimetry relies on the combined use of different types of instruments measuring the earth's gravity changes i.e. relative spring gravimeters (RG) and superconducting gravimeters (SG), as well as ballistic absolute gravimeters (AG) in a specific study. We show here that hybrid gravimetry is able to provide new constraints on underground water storage changes. We will focus on two special cases in West Africa which were investigated in the frame of the GHYRAF (Gravity and Hydrology in Africa) project: one is located in the semi-arid Sahelian zone in Wankama (Niger) and another one in Djougou (Benin) in the humid, hard-rock basement zone. In Wankama, both time-lapse AG and RG are available. In an innovative field survey during 3 months of the rainy season in 2009, we merged relative microgravimetry on a network of 12 stations, magnetic resonance soundings, and hydrological measurements to evaluate both surface and subsurface water storage variations. We show that most of the gravity variations originate from heterogeneities in the vadose zone highlighting the potential of time lapse microgravity surveys for detecting intraseasonal water storage variations in the critical zone. In Djougou, we will present the hydrology results coming from the use of the hybrid gravimetry approach based on a continuous record of a GWR SG installed since 2010 complemented with FG5 AG episodic measurements (4 times a year between 2008 and 2011 then yearly). In addition we also set up repeated micro-gravimetric measurements with a Scintrex CG5 RG on a dense network (more than 100 surveys and 15 stations) around the base station. The continuous SG record allows to bring additional insight on the space and time variable gravity (and hence water storage changes) in

  1. Capacity for scaling up nutrition: a focus on pre-service training in West Africa and a Ghanaian case study.

    PubMed

    Aryeetey, Richmond N O; Laar, Amos; Zotor, Francis

    2015-11-01

    The 2013 Lancet series on maternal and child nutrition is identified and advocated for improved institutional and human capacity in nutrition towards scaling up nutrition (SUN) in countries with high stunting rates. Of the fifty-four countries with high burden of child undernutrition who have committed to the SUN movement, thirty-six are in Africa. In the present paper, the academic platform of the SUN movement in Ghana presents an overview of nutrition pre-service capacity in West Africa with a focus on Ghana. The present paper is based on the findings of a sub-region-wide assessment of degree programmes in nutrition in West Africa, plus another report on pre-service nutrition capacity in diploma awarding nursing and nutrition programmes in Ghana. Although there is inadequate evidence on pre-service nutrition training in the sub-region, the two reports provide useful evidence for action, including inadequate number and distribution of pre-service nutrition training programmes, low nutrition graduate output, poor quality of the programme curriculum and instruction, and sub-optimal capital investment. The present paper calls for urgent action to improve pre-service nutrition capacity building as a critical step towards SUN in West Africa.

  2. Bias correction of daily precipitation projected by the CORDEX-Africa ensemble for a sparsely gauged region in West Africa with regionalized distribution parameters

    NASA Astrophysics Data System (ADS)

    Lorenz, Manuel; Bliefernicht, Jan; Laux, Patrick; Kunstmann, Harald

    2017-04-01

    Reliable estimates of future climatic conditions are indispensable for the sustainable planning of agricultural activities in West Africa. Precipitation time series of regional climate models (RCMs) typically exhibit a bias in the distribution of both rainfall intensities and wet day frequencies. Furthermore, the annual and monthly sums of precipitation may remarkably vary from the observations in this region. As West Africa experiences a distinct rainy season, sowing dates are oftentimes planned based on the beginning of this rainfall period. A biased representation of the annual cycle of precipitation in the uncorrected RCMs can therefore lead to crop failure. The precipitation ensemble, obtained from the Coordinated Downscaling Experiment CORDEX-Africa, was bias-corrected for the study region in West Africa (extending approximately 343,358 km2) which covers large parts of Burkina Faso, Ghana and Benin. In oder to debias the RCM precipitation simulations, a Quantile-Mapping method was applied to the historical period 1950-2005. For the RCM future projections (2006-2100), the Double-Quantile-Mapping procedure was chosen. This method makes use of the shift in the distribution function of the future precipitation values which allows to incorporate the climate change signal of the RCM projections into the bias correction. As large areas of the study region are ungauged, the assignment of the information from the nearest station to the ungauged location would lead to sharp changes in the estimated statistics from one location to another. Thus, the distribution parameters needed for the Quantile-Mapping were estimated by Kriging the distribution parameters of the available measurement stations. This way it is possible to obtain reasonable estimates of the expected distribution of precipitation at ungauged locations. The presentation will illustrate some aspects and trade-offs in the distribution parameter interpolation as well as an analysis of the uncertainties of the

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

    NASA Astrophysics Data System (ADS)

    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

  4. Hantaviruses in Africa.

    PubMed

    Witkowski, Peter T; Klempa, Boris; Ithete, Ndapewa L; Auste, Brita; Mfune, John K E; Hoveka, Julia; Matthee, Sonja; Preiser, Wolfgang; Kruger, Detlev H

    2014-07-17

    This paper summarizes the progress in the search for hantaviruses and hantavirus infections in Africa. After having collected molecular evidence of an indigenous African hantavirus in 2006, an intensive investigation for new hantaviruses has been started in small mammals. Various novel hantaviruses have been molecularly identified not only in rodents but also in shrews and bats. In addition, the first African hantavirus, Sangassou virus, has been isolated and functionally characterized in cell culture. Less is known about the ability of these hantaviruses to infect humans and to cause diseases. To date, no hantavirus genetic material could be amplified from patients' specimens collected in Africa. Serological studies in West Africa, based on a battery of screening and confirmatory assays, led to the detection of hantavirus antibodies in the human population and in patients with putative hantavirus disease. In addition to this overview, we present original data from seroepidemiological and field studies conducted in the Southern part of Africa. A human seroprevalence rate of 1.0% (n=1442) was detected in the South African Cape Region whereas no molecular evidence for the presence of hantavirus was found in 2500 small animals trapped in South Africa and Namibia.

  5. West Africa - A Safe Haven for Frogs? A Sub-Continental Assessment of the Chytrid Fungus (Batrachochytrium dendrobatidis)

    PubMed Central

    Penner, Johannes; Adum, Gilbert B.; McElroy, Matthew T.; Doherty-Bone, Thomas; Hirschfeld, Mareike; Sandberger, Laura; Weldon, Ché; Cunningham, Andrew A.; Ohst, Torsten; Wombwell, Emma; Portik, Daniel M.; Reid, Duncan; Hillers, Annika; Ofori-Boateng, Caleb; Oduro, William; Plötner, Jörg; Ohler, Annemarie; Leaché, Adam D.; Rödel, Mark-Oliver

    2013-01-01

    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). PMID:23426141

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

    PubMed

    Penner, Johannes; Adum, Gilbert B; McElroy, Matthew T; Doherty-Bone, Thomas; Hirschfeld, Mareike; Sandberger, Laura; Weldon, Ché; Cunningham, Andrew A; Ohst, Torsten; Wombwell, Emma; Portik, Daniel M; Reid, Duncan; Hillers, Annika; Ofori-Boateng, Caleb; Oduro, William; Plötner, Jörg; Ohler, Annemarie; Leaché, Adam D; Rödel, Mark-Oliver

    2013-01-01

    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).

  7. 'FAN the SUN brighter': fortifying Africa nutritionally (FAN) - the role of public private partnership in scaling up nutrition (SUN) in West Africa.

    PubMed

    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.

  8. Precipitation interannual variability and predictions for West Africa from the National Multi-Model Ensemble dataset

    NASA Astrophysics Data System (ADS)

    Thiaw, W. M.

    2013-12-01

    The ability of coupled climate models from the national multi-model ensemble (NMME) dataset to reproduce the basic state and interannual variability of precipitation in West Africa and associated teleconnections is examined. The analysis is for the period 1982-2010 for most of the models, which corresponds to the NMME hindcast period, except for the CFS version 1 (CFSv1) which covers the period 1981-2009. The satellite based CPC African Rainfall Climatology (ARC2) data is used as proxy for observed rainfall and to validate the models. We examine rainfall patterns throughout the year. Models are able to reproduce the north-south migration of precipitation from winter and spring when the area of maximum precipitation is located in Central Africa and the Gulf of Guinea region to the summer when it is in northern Sub-Saharan Africa, and the later return to the south. Models also appropriately place precipitation over the Gulf of Guinea region during the equinoxes in MAM and OND. However, there are considerable differences in the representation of the intensities and locations of the rainfall. Three of the models including the two versions of the NCEP CFS and the NASA models also have a systematic dry (wet) bias over the Sahel (Gulf of Guinea region) during the summer rainfall season, while the others show alternating wet and dry biases across West Africa. All models have spatially averaged values of standard deviation lower than that observed. Models are also able to reproduce to some extent the main features of the precipitation variability maximum, but again with deficiencies in the amplitudes and locations. The areas of highest variability are generally depicted, but there are significant differences among the models, and even between the two versions of the CFS. Teleconnections in the models are investigated by first conducting an EOF in the precipitation anomaly fields and then perform a regression of the first or second EOF time series onto the global SST

  9. Identification and Diagnosis of Rainfall Types over Southern West Africa Using Satellite and Rain Gauge Data

    NASA Astrophysics Data System (ADS)

    Maranan, Marlon; Fink, Andreas H.; Amekudzi, Leonard K.; Atiah, Winifred A.

    2017-04-01

    Rainfall over Southern West Africa (SWA) is mainly controlled by the West African Monsoon circulation. Not much is known, however, about the (thermo-)dynamic environmental conditions and storm dynamics of various regional rainfall systems that contribute to the total annual rainfall. This study exploits both satellite and rain gauge measurements to quantify the contribution and to examine the importance of different rainfall types in SWA. For the period of the Tropical Rainfall Measuring Mission (TRMM) 1998-2014, the rainfall types are identified by analyzing the 3-D reflectivity structure using scans of the TRMM Precipitation Radar (TRMM-PR). Since TRMM-PR scans only provide instantaneous snapshots, the rainfall events are then traced back and forward in time with observations from the Spinning Enhanced Visible and Infrared Imager (SEVIRI) over the overlapping period of 2004-2014 to obtain information about their life cycle. The composition of the ensemble of the different rainfall types exhibits a substantial regional variability across SWA. Strong convection (Radar echo > 40 dBZ) generally makes a dominant contribution to the number of rainfall events and to the total rainfall amount. However, the influence of deeper (40 dBZ echo at altitudes > 10 km) and wider (Area of 40 dBZ echo > 1000 km2) systems on the total rainfall amount increases going farther northward into the continent. Additionally, the number of tracks of those systems features relative minima along the Ivorian and Ghanaian-Togolese coast, the latter reflecting the climatologically dry Dahomey Gap. In contrast, local warm rain from isolated shallow convection develops more often along the immediate coast line. Yet, their contribution to total rainfall remains negligible and is almost non-existent further north. Compared with high-resolution rain gauge data around Kumasi, Ghana, for the year 2016, it can be assumed that warm rain events show an even higher occurrence frequency. Likewise, their

  10. Dynamic Topography in the Oceanic Realm of West Africa, India, and the Gulf of Mexico

    NASA Astrophysics Data System (ADS)

    Hoggard, M. J.; Roberts, G.; White, N. J.

    2012-12-01

    It is generally agreed that convection in the mantle can generate vertical motions at the Earth's surface. Consequently, the recorded history of subsidence and uplift holds important clues about mantle convection. We use the well-established relationship between seafloor subsidence and age to map present-day residual depth anomalies in the oceanic realm. This map yields estimates of the spatial variation of dynamic topography, providing care is taken to rule out other potential causes of subsidence or uplift such as flexure adjacent to seamounts and subduction zones. Global analysis indicates that anomalies typically vary between ±1 km, over wavelengths of ~1000 km. This analysis of residual topography is concentrated on the oldest oceanic crust that abuts continental margins in order to provide a leg up onto the continents, where measuring absolute values of dynamic topography is considerably more complicated. Here we begin by looking at three areas in more detail - the west coast of Africa, India and the Gulf of Mexico. Residual depths along the west coast of Africa capture two full wavelengths of dynamic topography, which correlate well with the long-wavelength free air gravity anomaly. To constrain the temporal evolution of dynamic topography, we focus on regions such as the Gulf of Mexico which is currently drawn-down by ~2 km at its centre. Backstripping stratigraphic data from wells implies the majority of the anomalous subsidence has occurred in the last ~15 Ma. The east coast of India shows a drawdown of 2 km beneath the Bengal fan and the development of this anomaly is clearly recorded in the transition from progradational to aggradational behaviour within the margin's clinoform architecture. Analysis of adjacent river profiles indicates recent onshore uplift has provided high quantities of clastic detritus that have been deposited on the margin. Oceanic residual depths along the west African margin overlain by the long wavelength filtered free air

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

    PubMed

    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

  12. Sustainable Development of Research Capacity in West Africa based on the GLOWA Volta Project

    NASA Astrophysics Data System (ADS)

    Liebe, Jens R.; Rogmann, Antonio; Falk, Ulrike; Amisigo, Barnabas; Nyarko, Kofi; Harmsen, Karl; Vlek, Paul L. G.

    2010-05-01

    The Sustainable Development of Research Capacity (SDRC) in West Africa is an 18 month project, funded by the German Ministry of Education and Research, to strengthen the research capacity, give access to data and models, and to support the establishment of the newly formed Volta Basin Authority. The SDRC project largely builds on the results and models developed in the framework of the GLOWA Volta Project (GVP), a nine-year, interdisciplinary research project (May 2000 - May 2009). The GVP's central objectives were to analyze the physical and socio-economic determinants of the hydrological cycle in the Volta Basin in the face of global change, and to develop scientifically sound decision support resources. Another major achievement of GVP was the extensive capacity building. Of the 81 participating students (57 Ph.D.'s), 44 originated from West Africa, and 85% of the West African graduates returned to their home countries. The SDRC makes use of the wide range of research results and decision support tools developed in the course of the GVP. It is based on three columns: I. knowledge transfer and strengthening of human capacity, which focus on a training on the modeling of the onset of the rainy season, hydrological, economic, and hydro-economic modeling, and training of geospatial database managers; II. strengthening of infrastructural research capacity through the support of a research instrumentation network through the operation and transfer of a weather station network, a network of tele-transmitted stream gauges; and III. the transfer of a publicly accessible online Geoportal for the dissemination of various geospatial data and research results. At the center of the SDRC effort is the strengthening of the Volta Basin Authority, a river basin authority with a transnational mandate, especially through the transfer of the Geoportal, and the associated training and promotion efforts. The Geoportal is an effort to overcome the data scarcity previously observed in

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

    PubMed

    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

  14. [An approach to food consumption in an urban environment. The case of west Africa].

    PubMed

    Ag Bendech, M; Gerbouin-Rerolle, P; Chauliac, M; Malvy, D

    1996-01-01

    West Africa has undergone rapid economic and political changes during the last 20 years. After the failure of economic policies implemented since independence, programs for structural adjustment have strongly influenced the economy. Food problems affect each country differently. The Sahel has experienced food shortages and starvation whereas in forested countries the food supply has remained stable. Nevertheless, food policies have not succeeded in contributing to urban and rural development. The rate of urbanization in west Africa is generally low but the rate of urban population growth is particularly high, much more than the growth rates of industry and infrastructure. Although metropolitan areas are affected by poverty, they offer more hope and opportunities than rural areas. Urban markets have expanded and diversified as social differences have also increased and contributed to changes in consumption structure. Urban growth has contributed to the increase of imported food: this is indicated by both the strong dependency and the change of food habits towards western food patterns. Recently however, west African urban dwellers are still preferring local items if they are affordable. When imported products are used, they are integrated within a stable meal plan consisting of a single dish with a base and a sauce, which is typical of African food preparation. Surveys of consumption-budgets are still only available on a national scale. These can provide accurate information about food consumption patterns of families, particularly for significant trends. However, they do not provide information about the dynamics of food consumption, neither for urban areas or the individual. Now a significant proportion of individual food consumption occurs outside of the home, mainly with food provided by street vendors. This new consumption habit is a response to the urban food crisis. Consumption of street-vendor-food comprises one component but this cannot be dissociated from

  15. The Delivery of an Effective Collective Security Mechanism in West Africa: It Is Long Overdue

    DTIC Science & Technology

    2014-06-13

    Force AU African Union CAR Central Africa Republic CEWS Continental Early Warning System CNDP National Congress for the Defense of the People DoD...Architecture provides hope that the continent is ready to face its 11 challenges with a united front, without which the people of Africa will...independent people struggling with its internal disease; hence it would itself be an offense and would render the autonomy of all states insecure. (Kant

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

    PubMed

    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.

  17. Seasonal Variations of Water, Energy, and Carbon Fluxes Across a Moisture Gradient in West Africa

    NASA Astrophysics Data System (ADS)

    Smith, D.; Baker, I. T.; Denning, S.; Stockli, R.; Orescanin, B.

    2013-12-01

    While grasslands make up nearly 40% of Earth's land surface, many areas remain understudied and under observed. Particularly, tropical grasslands are generally less researched sites due to the remoteness of their location. Model output and satellite data have become key resources when describing and analyzing the ecological processes occurring in these areas. In this project, the Simple Biosphere Model (SiB) and fluorescence data are used alongside each other to summarize the productivity both seasonally and annually in several grassland sites in West Africa. While SiB interpreted the overall meteorological processes fairly well, the model struggled to accurately describe the variations in leaf indices, including; leaf area index, fraction of photosynthetically active radiation, and fluorescence. Specifically, fluorescence data retrieved by satellite showed variability seasonally, whereas, SiB showed very little. To improve SiB's output, the phenology of each grassland site are examined and altered to create a more realistic description than what had been previously used. The adaption resulted in more accurate modeling of ecological processes in West African grasslands. Comparing the Simple Biosphere Model (SiB) to remotely sensed observations.

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

    PubMed Central

    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. PMID:28352500

  19. Pleistocene refugia and genetic diversity patterns in West Africa: Insights from the liana Chasmanthera dependens (Menispermaceae)

    PubMed Central

    Schmidt, Marco; Muellner-Riehl, Alexandra Nora; Ogundipe, Oluwatoyin Temitayo; Paule, Juraj

    2017-01-01

    Processes shaping the African Guineo-Congolian rain forest, especially in the West African part, are not well understood. Recent molecular studies, based mainly on forest tree species, confirmed the previously proposed division of the western African Guineo-Congolian rain forest into Upper Guinea (UG) and Lower Guinea (LG) separated by the Dahomey Gap (DG). Here we studied nine populations in the area of the DG and the borders of LG and UG of the widespread liana species, Chasmanthera dependens (Menispermaceae) by amplified fragment length polymorphism (AFLP), a chloroplast DNA sequence marker, and modelled the distribution based on current as well as paleoclimatic data (Holocene Climate Optimum, ca. 6 kyr BP and Last Glacial Maximum, ca. 22 kyr BP). Current population genetic structure and geographical pattern of cpDNA was related to present as well as historical modelled distributions. Results from this study show that past historical factors played an important role in shaping the distribution of C. dependens across West Africa. The Cameroon Volcanic Line seems to represent a barrier for gene flow in the present as well as in the past. Distribution modelling proposed refugia in the Dahomey Gap, supported also by higher genetic diversity. This is in contrast with the phylogeographic patterns observed in several rainforest tree species and could be explained by either diverging or more relaxed ecological requirements of this liana species. PMID:28301470

  20. Study of the mixing and ageing of polluted plumes from major West Africa cities

    NASA Astrophysics Data System (ADS)

    Tocquer, Flore; Mari, Céline; Leriche, Maud; Dacciwa Team

    2017-04-01

    Massive economic and population growth, fast urbanization in megacities along the Guinea Coast, would triple anthropogenic emissions by 2030 (Knippertz et al., 2015). Impacts of the rapid increase of atmospheric pollutants on weather and climate in this region are largely unstudied due to a lack of observations. The DACCIWA (Dynamics-aerosol-chemistry-cloud interactions in West Africa) project carried out an important airborne measurements campaign in June-July 2016 together with ground-based observations in urban and remote sites. Urban and industrial, biogenic dominated environment, dust and biomass burning air masses, ship plumes and flaring emissions were sampled successfully. The goal of this work is to investigate the transport and ageing of anthropogenic emissions from major West African megacities during boreal summer. For this purpose, the coupled atmosphere-chemistry mesoscale model Méso-NH was run at kilometric scale and results were compared with in-situ meteorological and chemical data. The study focuses on 06-07-08 July 2016. Three research aircrafts operated over the coastal region sampling downwind pollution from Lomé and Accra and biogenic emissions further inland. Preliminary simulation results will be presented to understand the mixing between and ageing of cities plumes during the post-onset period of the campaign.

  1. Fatalism and HIV/AIDS beliefs in rural Mali, West Africa.

    PubMed

    Hess, Rosanna F; McKinney, Dawn

    2007-01-01

    To examine beliefs about HIV/AIDS of rural Malians and to measure their level of fatalism in context of HIV/AIDS and prevention behaviors. Descriptive, correlational. An AIDS Knowledge and Beliefs survey and the Powe Fatalism Inventory (PFI)-HIV/AIDS version were administered to a convenience sample of 84 people at three health center maternity clinics in southeastern Mali, West Africa. The sample's HIV/AIDS fatalism mean was 9.2 on a 15-point scale, with an internal consistency of .89. Health workers and more educated participants had significantly lower fatalism scores. Fatalism also varied by the combination of gender and ethnicity. People who believed that AIDS was not real, was a punishment from God, was fabricated by the West, was a curse, and that it was taboo to talk about AIDS had higher fatalism means. None of the prevention indicators were significantly related to fatalism scores. These rural Malians had a high overall fatalism mean and their beliefs about AIDS based on traditional culture may affect prevention behaviors. More research is needed to understand the influence of fatalism on prevention behaviors.

  2. Understanding the impact of land use change on climate in West Africa

    NASA Astrophysics Data System (ADS)

    Taylor, C. M.; Lambin, E. F.; Stephenne, N.; Oregan, D. P.; Harding, R. J.

    2003-04-01

    The Sahel has experienced a prolonged period of below average rainfall since the 1960s, and a number of studies have linked this to anthropogenic changes in vegetation. Previous numerical modelling experiments have shown that taking locally observed vegetation changes and extrapolating them over the entire region results in substantial reductions in rainfall. In fact, the intensity and geographical extent of actual vegetation change over recent decades are not well known. In this study, we present the sensitivity of the West African climate simulated by the Met Office/Hadley Centre Atmospheric General Circulation Model to more realistic estimates of land cover change. In the Sahel region, estimates are generated by a dynamic simulation model of land use change. This simulates the key processes associated with changing human and livestock populations, urbanisation, commercialisation of crop production and climate variability. In the tropical belt of West and Central Africa, simple deforestation scenarios are adopted, based on the Forestry Research Assessment of 2000. The sensitivity of the climate to land use is compared with simulations using global sea surface temperature patterns from extreme years. Additional simulations are performed which take into account the natural variability in biomass associated with climatic anomalies. The relative impacts of each of these factors on past and future climate in the region will be discussed.

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

    PubMed

    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. © 2015 John Wiley & Sons Ltd.

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

    PubMed

    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.

  5. A GCM study of the response of the atmospheric water cycle of West Africa and the Atlantic to Saharan dust radiative forcing

    NASA Astrophysics Data System (ADS)

    Lau, K. M.; Kim, K. M.; Sud, Y. C.; Walker, G. K.

    2009-10-01

    The responses of the atmospheric water cycle and climate of West Africa and the Atlantic to radiative forcing of Saharan dust are studied using the NASA finite volume general circulation model (fvGCM), coupled to a mixed layer ocean. We find evidence of an "elevated heat pump" (EHP) mechanism that underlines the responses of the atmospheric water cycle to dust forcing as follow. During the boreal summer, as a result of large-scale atmospheric feedback triggered by absorbing dust aerosols, rainfall and cloudiness are enhanced over the West Africa/Eastern Atlantic ITCZ, and suppressed over the West Atlantic and Caribbean region. Shortwave radiation absorption by dust warms the atmosphere and cools the surface, while longwave has the opposite response. The elevated dust layer warms the air over West Africa and the eastern Atlantic. As the warm air rises, it spawns a large-scale onshore flow carrying the moist air from the eastern Atlantic and the Gulf of Guinea. The onshore flow in turn enhances the deep convection over West Africa land, and the eastern Atlantic. The condensation heating associated with the ensuing deep convection drives and maintains an anomalous large-scale east-west overturning circulation with rising motion over West Africa/eastern Atlantic, and sinking motion over the Caribbean region. The response also includes a strengthening of the West African monsoon, manifested in a northward shift of the West Africa precipitation over land, increased low-level westerly flow over West Africa at the southern edge of the dust layer, and a near surface westerly jet underneath the dust layer over the Sahara. The dust radiative forcing also leads to significant changes in surface energy fluxes, resulting in cooling of the West African land and the eastern Atlantic, and warming in the West Atlantic and Caribbean. The EHP effect is most effective for moderate to highly absorbing dusts, and becomes minimized for reflecting dust with single scattering albedo at 0

  6. A GCM Study of Responses of the Atmospheric Water Cycle of West Africa and the Atlantic to Saharan Dust Radiative Forcing

    NASA Technical Reports Server (NTRS)

    Lau, K. M.; Kim, K. M.; Sud, Y. C.; Walker, G. K.

    2009-01-01

    The responses of the atmospheric water cycle and climate of West Africa and the Atlantic to radiative forcing of Saharan dust are studied using the NASA finite volume general circulation model (fvGCM), coupled to a mixed layer ocean. We find evidence of an "elevated heat pump" (EHP) mechanism that underlines the responses of the atmospheric water cycle to dust forcing as follow. During the boreal summerr, as a result of large-scale atmospheric feedback triggered by absorbing dust aerosols, rainfall and cloudiness are ehanIed over the West Africa/Eastern Atlantic ITCZ, and suppressed over the West Atlantic and Caribbean region. Shortwave radiation absorption by dust warms the atmosphere and cools the surface, while longwave has the opposite response. The elevated dust layer warms the air over West Africa and the eastern Atlantic. As the warm air rises, it spawns a large-scale onshore flow carrying the moist air from the eastern Atlantic and the Gulf of Guinea. The onshore flow in turn enhances the deep convection over West Africa land, and the eastern Atlantic. The condensation heating associated with the ensuing deep convection drives and maintains an anomalous large-scale east-west overturning circulation with rising motion over West Africa/eastern Atlantic, and sinking motion over the Caribbean region. The response also includes a strengthening of the West African monsoon, manifested in a northward shift of the West Africa precipitation over land, increased low-level westerlies flow over West Africa at the southern edge of the dust layer, and a near surface westerly jet underneath the dust layer overr the Sahara. The dust radiative forcing also leads to significant changes in surface energy fluxes, resulting in cooling of the West African land and the eastern Atlantic, and warming in the West Atlantic and Caribbean. The EHP effect is most effective for moderate to highly absorbing dusts, and becomes minimized for reflecting dust with single scattering albedo at0

  7. Marine Incursion: The Freshwater Herring of Lake Tanganyika Are the Product of a Marine Invasion into West Africa

    PubMed Central

    Wilson, Anthony B.; Teugels, Guy G.; Meyer, Axel

    2008-01-01

    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. PMID:18431469

  8. Marine incursion: the freshwater herring of Lake Tanganyika are the product of a marine invasion into west Africa.

    PubMed

    Wilson, Anthony B; Teugels, Guy G; Meyer, Axel

    2008-04-23

    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. Moko Jumbies: Dancing Spirits from Africa

    ERIC Educational Resources Information Center

    Bennett, S. A.; Phillips, Claire; Moore, Natalie

    2009-01-01

    The original Moko Jumbie was a spirit dancer from West Africa. "Moko" is a West African word that refers to gods and "Jumbie" means ghost. In West Africa, Moko Jumbies are known to kidnap and eat disobedient children, steal dreams and see into evildoers' hearts and terrorize them. They walk through villages on 10- to…

  10. Moko Jumbies: Dancing Spirits from Africa

    ERIC Educational Resources Information Center

    Bennett, S. A.; Phillips, Claire; Moore, Natalie

    2009-01-01

    The original Moko Jumbie was a spirit dancer from West Africa. "Moko" is a West African word that refers to gods and "Jumbie" means ghost. In West Africa, Moko Jumbies are known to kidnap and eat disobedient children, steal dreams and see into evildoers' hearts and terrorize them. They walk through villages on 10- to…

  11. Gambian-British and Nigerian-British Children's and Families' Experiences of Migration "Back" to West Africa. Research Briefing No. 13

    ERIC Educational Resources Information Center

    Roberts-Holmes, Guy

    2013-01-01

    This research looks at the factors motivating Gambian-British and Nigerian-British parents to send their children "back" to West Africa and what this means for parents, children and families on both continents.

  12. Gambian-British and Nigerian-British Children's and Families' Experiences of Migration "Back" to West Africa. Research Briefing No. 13

    ERIC Educational Resources Information Center

    Roberts-Holmes, Guy

    2013-01-01

    This research looks at the factors motivating Gambian-British and Nigerian-British parents to send their children "back" to West Africa and what this means for parents, children and families on both continents.

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

    NASA Astrophysics Data System (ADS)

    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.

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

    PubMed

    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. Copyright © 2016

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

    SciTech Connect

    Zhao, Chun; Liu, Xiaohong; Leung, Lai-Yung R.; Hagos, Samson M.

    2011-03-01

    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 AOD over West Africa. In the standard simulation, on 24-hour 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/hour (30%) and an increase of nocturnal and early morning precipitation by up to 0.04 mm/hour (23%) 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 (-0.14 mm/day or -4%). On the other hand, sensitivity simulations show that, for weaker-to-stronger absorbing dust, 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 -0.40 mm/day (-12%, weaker absorbing dust) to a small increase of 0.05 mm/day (1%, stronger absorbing dust). This variation originates from the competition between dust impact on daytime and nighttime precipitation, which depends on dust shortwave absorption. Dust reduces the diurnal variation of precipitation regardless of its absorptivity, but more reduction is associated with stronger absorbing dust.

  16. Travelers' diarrhea in West Africa and Mexico: fecal transport systems and liquid bismuth subsalicylate for self-therapy.

    PubMed

    Steffen, R; Mathewson, J J; Ericsson, C D; DuPont, H L; Helminger, A; Balm, T K; Wolff, K; Witassek, F

    1988-05-01

    The goals of this study were threefold: to compare the etiology of travelers' diarrhea in West Africa and Mexico, to evaluate two fecal transport systems for the recovery of enteropathogens, and to verify the efficacy of liquid bismuth subsalicylate (BSS) in different locations and under different entrance criteria for disease severity. The study populations consisted of 133 European tourists in West Africa and 112 American students in Mexico who had suffered from travelers' diarrhea. In 60% and 38% of the stool samples at the two study sites, similar proportions of enteropathogens were detected. A two-vial system consisting of Enteric Plus medium and polyvinyl alcohol fixative was slightly superior for identifying enteric pathogens than was a three-vial system with buffered glycerol saline, Cary-Blair medium with campylobacter antibodies, and polyvinyl alcohol fixative. In a parallel, double-blind, randomized trial, BSS significantly shortened disease duration at both study sites.

  17. Assessment of undiscovered oil and gas resources of the West African Costal Province, West Africa

    USGS Publications Warehouse

    Brownfield, Michael E.; Charpentier, Ronald R.; Schenk, Christopher J.; Klett, Timothy R.; Cook, Troy A.; Pollastro, Richard M.

    2011-01-01

    The West African Coastal Province along the west African coastline recently was assessed for undiscovered, technically recoverable oil, natural gas, and natural gas liquids resources as part of the U.S. Geological Survey's USGS World Oil and Gas Assessment. Using a geology-based assessment methodology, the USGS estimated mean volumes of 3.2 billion barrels of oil, 23.63 trillion cubic feet of natural gas, and 721 million barrels of natural gas liquids.

  18. Enough Room for the Eagle and Dragon Chinese Resource Extraction and its Impact on U.S. on U.S Military Operations in West Africa

    DTIC Science & Technology

    2017-06-09

    terrorist groups began to gather on the fringes of West Africa, presenting regional security concerns with potentially global impacts. But was China’s...foothold in the region enough to hinder or prevent U.S. military access to the region ? This research study explores the impact of China’s state run...national terrorist groups began to gather on the fringes of West Africa, presenting regional security concerns with potentially global impacts. But was

  19. Genetically Different Highly Pathogenic Avian Influenza A(H5N1) Viruses in West Africa, 2015

    PubMed Central

    Tassoni, Luca; Fusaro, Alice; Milani, Adelaide; Lemey, Philippe; Awuni, Joseph Adongo; Sedor, Victoria Bernice; Dogbey, Otilia; Commey, Abraham Nii Okai; Meseko, Clement; Joannis, Tony; Minoungou, Germaine L.; Ouattara, Lassina; Haido, Abdoul Malick; Cisse-Aman, Diarra; Couacy-Hymann, Emmanuel; Dauphin, Gwenaelle; Cattoli, Giovanni

    2016-01-01

    To trace the evolution of highly pathogenic influenza A(H5N1) virus in West Africa, we sequenced genomes of 43 viruses collected during 2015 from poultry and wild birds in 5 countries. We found 2 co-circulating genetic groups within clade 2.3.2.1c. Mutations that may increase adaptation to mammals raise concern over possible risk for humans. PMID:27389972

  20. Impact of Military Coups d’etat on West Africa’s Socio-Economic and Political Development

    DTIC Science & Technology

    2011-12-16

    exports: oil is the principle revenue-earner for Nigeria; cocoa and gold are the major exporting commodities of Ghana; several countries have...example, the United Nations’ presence in the Mano River Basin has provided much needed security and has benefited the region in many ways. For...Nations Economic Commission for Africa (UNECA), West African countries benefited from the high oil prices in 2010 and revenues from non- oil

  1. DPA1*02012: A DPA1*0201-related Mhc class II allele in West Africa

    SciTech Connect

    Meyer, C.G.; May, J.; Spauke, D.; Schnittger, L.

    1994-12-31

    DNA techniques such as sequence-specific oligonucleotide probe (SSOP) hybridizations, restriction-fragment length polymorphism (RFLP) analyses, and DNA sequencing have greatly supported the characterization of Mhc class II allelic polymorphism. Here the authors describe a DPA 1 allele which has been identified in two male individuals from Liberia and Benin, West Africa, during a survey study on Mhc class II associations with the different manifestations after infection with Onchocerca volvulus. 4 refs., 1 fig.

  2. Investigating GRACE Range-Rate Observations over West Africa with respect to Small-Scale Hydrological Signals

    NASA Astrophysics Data System (ADS)

    Springer, A.; Eicker, A.; Kusche, J.; Longuevergne, L.; Diekkrüger, B.; Jütten, T.

    2015-12-01

    Here, GRACE K-band range rate (KBRR) observations are analyzed for the effects from small-scale hydrological signals over West Africa including water level changes in reservoirs, extreme weather events, and water storage variability predicted by hydrological models. The presented approach, which is based on level 1B data, avoids the downward continuation and filtering process required for computing monthly gravity field solutions and, thus, enables to assess hydrological signals with a high temporal resolution and at small spatial scales. In a first step, water mass variations derived from tide gauges, altimetry, and from hydrological model output are converted into simulated KBRR observations. Secondly, these simulated observations and a number of geophysical corrections are reduced from the original GRACE K-band observations to obtain the residuals for a time span of ten years. Then, (i) the residuals are used to validate differently modeled water mass variations and (ii) extreme weather events are identified in the residuals. West Africa represents an interesting study region as it is increasingly facing exteme precipitation events and floodings. In this study, monthly and daily output from different global hydrological models is validated for their representation of long-term and short-term (daily) water storage variability over West Africa. The daily RMS of KBRR residuals ranges between 0.1 μm/s and 0.7 μm/s. Smaller residuals imply that the model is able to better explain the observations. For example, we find that in 2007 the Land Surface Discharge Model (LSDM) better agrees with GRACE range-rate observations than the Water-GAP Global Hydrology Model (WGHM) and the GLDAS-Noah land surface model. Furthermore, we confirm previous studies and show that the signal from Lake Volta is distinctly contained in the residuals. Finally, we investigate variations of other smaller reservoirs and the floodings over West Africa in June 2009 and over Benin in October 2010.

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

    NASA Astrophysics Data System (ADS)

    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.

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

    NASA Astrophysics Data System (ADS)

    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.

  5. Evolution of the atmospheric boundary layer in southern West Africa - an overview from the DACCIWA field campaign

    NASA Astrophysics Data System (ADS)

    Kalthoff, Norbert; Lohou, Fabienne; Brooks, Barbara; Jegede, Gbenga; Adler, Bianca; Ajao, Adewale; Ayoola, Muritala; Babić, Karmen; Bessardon, Geoffrey; Delon, Claire; Dione, Cheikh; Handwerker, Jan; Jambert, Corinne; Kohler, Martin; Lothon, Marie; Pedruzo-Bagazgoitia, Xabier; Smith, Victoria; Sunmonu, Lukman; Wieser, Andreas

    2017-04-01

    In southern West Africa, extended low-level stratus clouds form very frequently during night-time and persist long into the following day influencing the diurnal cycle of the atmospheric boundary layer (ABL). During the course of the day, a transition from nocturnal low-level stratus to stratocumulus, cumulus, and sometimes congestus and possibly cumulonimbus clouds is observed. In June and July 2016, a ground-based field campaign took place in southern West Africa within the framework of the Dynamics-aerosol-chemistry-cloud interactions in West Africa (DACCIWA) project with the aim to identify the meteorological controls on the stratus and the evolution of the ABL. During the measurement period, extensive remote sensing and in-situ measurements were performed at three supersites in Kumasi (Ghana), Savè (Benin) and Ile-Ife (Nigeria). We give an overview of the atmospheric conditions during the whole measurement period focusing on the vertical and temporal distribution of the stratus and relevant related atmospheric features.

  6. Mitochondrial DNA variability in Giraffa camelopardalis: consequences for taxonomy, phylogeography and conservation of giraffes in West and central Africa.

    PubMed

    Hassanin, Alexandre; Ropiquet, Anne; Gourmand, Anne-Laure; Chardonnet, Bertrand; Rigoulet, Jacques

    2007-03-01

    The giraffe (Giraffa camelopardalis) still survives in four countries of West and central Africa. The populations of Niger and Cameroon are generally assigned to the subspecies peralta, but those of Chad and the Central African Republic are taxonomically problematic, as they are referred to as either peralta, or antiquorum, or congoensis. In this study, a mitochondrial fragment of 1765 nucleotide sites, covering the complete cytochrome b gene, three transfer RNAs and a large part of the control region, was sequenced to assess the relationships between several populations of giraffe. The phylogenetic analyses performed on the 12 identified haplotypes indicate that northern giraffes constitute a natural group, distinct from that of southern giraffes. Surprisingly, the giraffes of Niger are found to be more closely related to the giraffes of East Africa (subspecies rothschildi and reticulata) than to those of central Africa. We conclude therefore that the subspecies peralta contains only the Niger giraffes, whereas the subspecies antiquorum includes all populations living in Cameroon, Chad, the Central African Republic, and southwestern Sudan. We suggest that the ancestor of the Nigerian giraffe dispersed from East to North Africa during the Quaternary period and thereafter migrated to its current Sahelian distribution in West Africa, in response to the development of the Sahara desert. This hypothesis implies that Lake Mega-Chad acted as a strong geographical barrier during the Holocene, preventing any contact between the subspecies peralta and antiquorum. Our study has direct implications for conservation management, as we show that no subspecies peralta is represented in any European zoos, only in Niger, with a small population of less than 200 individuals.

  7. Bilharziasis survey in British West and East Africa, Nyasaland, and the Rhodesias*

    PubMed Central

    Blair, Dyson M.

    1956-01-01

    The author, in his capacity as a WHO consultant, undertook a survey of bilharziasis in British West and East Africa and Nyasaland during 1950-51. The information thus obtained has been revised and brought up to date and is recorded in the present article together with similar observations on Northern Rhodesia, which was not visited, and on Southern Rhodesia, the author's own country. In Part I, each country is dealt with in turn. The history of the disease and the findings of field surveys are reviewed, and, wherever possible, personal observations have been included. The fact that the information is of a scanty and incomplete nature is an indication that further local studies in all areas are badly needed. In Part II an attempt is made to survey the situation from the point of view of the various aspects of the subjects—methods of obtaining morbidity data, intensity of infection, effects of the disease on human health, treatment, and the molluscan vectors. PMID:13383363

  8. Poverty, health and satellite-derived vegetation indices: their inter-spatial relationship in West Africa

    PubMed Central

    Sedda, Luigi; Tatem, Andrew J.; Morley, David W.; Atkinson, Peter M.; Wardrop, Nicola A.; Pezzulo, Carla; Sorichetta, Alessandro; Kuleszo, Joanna; Rogers, David J.

    2015-01-01

    Background Previous analyses have shown the individual correlations between poverty, health and satellite-derived vegetation indices such as the normalized difference vegetation index (NDVI). However, generally these analyses did not explore the statistical interconnections between poverty, health outcomes and NDVI. Methods In this research aspatial methods (principal component analysis) and spatial models (variography, factorial kriging and cokriging) were applied to investigate the correlations and spatial relationships between intensity of poverty, health (expressed as child mortality and undernutrition), and NDVI for a large area of West Africa. Results This research showed that the intensity of poverty (and hence child mortality and nutrition) varies inversely with NDVI. From the spatial point-of-view, similarities in the spatial variation of intensity of poverty and NDVI were found. Conclusions These results highlight the utility of satellite-based metrics for poverty models including health and ecological components and, in general for large scale analysis, estimation and optimisation of multidimensional poverty metrics. However, it also stresses the need for further studies on the causes of the association between NDVI, health and poverty. Once these relationships are confirmed and better understood, the presence of this ecological component in poverty metrics has the potential to facilitate the analysis of the impacts of climate change on the rural populations afflicted by poverty and child mortality. PMID:25733559

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

    NASA Astrophysics Data System (ADS)

    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.

  10. Insecticide resistance in field populations of Bemisia tabaci (Hemiptera: Aleyrodidae) in West Africa.

    PubMed

    Houndété, Thomas A; Kétoh, Guillaume K; Hema, Omer S A; Brévault, Thierry; Glitho, Isabelle A; Martin, Thibaud

    2010-11-01

    The tobacco whitefly, Bemisia tabaci Gennadius (Hemiptera: Aleyrodidae), has developed a high degree of resistance to several chemical classes of insecticides throughout the world. To evaluate the resistance status in West Africa, eight insecticides from different chemical families were tested using the leaf-dip method on four field populations collected from cotton in Benin, Togo and Burkina Faso. Some field populations showed a significant loss of susceptibility to pyrethroids such as deltamethrin [resistance ratio (RR) 3-5] and bifenthrin (RR 4-36), to organophosphates (OPs) such as dimethoate (RR 8-15) and chlorpyrifos (RR 5-7) and to neonicotinoids such as acetamiprid (RR 7-8) and thiamethoxam (RR 3-7). Bemisia tabaci was also resistant to pymetrozine (RR 3-18) and to endosulfan (RR 14-30). The resistance of B. tabaci to pyrethroids and OPs is certainly due to their systematic use in cotton treatments for more than 30 years. Acetamiprid has been recently introduced for the control of whiteflies. Unfortunately, B. tabaci populations from Burkina Faso seem to be already resistant. Because cross-resistance between these compounds has never been observed elsewhere, resistance to neonicotinoids could be due to the presence of an invasive B. tabaci biotype recently detected in the region. Copyright © 2010 Society of Chemical Industry.

  11. Multisensor monitoring of deforestation in the Guinea Highlands of West Africa

    NASA Technical Reports Server (NTRS)

    Gilruth, Peter T.; Hutchinson, Charles F.

    1990-01-01

    Multiple remote sensing systems were used to assess deforestation in the Guinea Highlands (Fouta Djallon) of West Africa. Sensor systems included: (1) historical (1953) and current (1989) aerial mapping photography; (2) current large-scale, small format (35mm) aerial photography; (3) current aerial video imagery; and (4) historical (1973) and recent (1985) LANDSAT MSS. Photographic and video data were manually interpreted and incorporated in a vector-based geographic information system (GIS). LANDSAT data were digitally classified. General results showed an increase in permanent and shifting agriculture over the past 35 years. This finding is consistent with hypothesized strategies to increase agricultural production through a shortening of the fallow period in areas of shifting cultivation. However, results also show that the total area of both permanent and shifting agriculture had expanded at the expense of natural vegetation and an increase in erosion. Although sequential LANDSAT MSS cannot be used in this region to accurately map land over, the location, direction and magnitude of changes can be detected in relative terms. Historical and current aerial photography can be used to map agricultural land use changes with some accuracy. Video imagery is useful as ancillary data for mapping vegetation. The most prudent approach to mapping deforestation would incorporate a multistage approach based on these sensors.

  12. Assessing the performance of dynamical and statistical downscaling techniques to simulate crop yield in West Africa

    NASA Astrophysics Data System (ADS)

    Sultan, B.; Oettli, P.; Vrac, M.; Baron, C.

    2010-12-01

    Global circulation models (GCM) are increasingly capable of making relevant predictions of seasonal and long-term climate variability, thus improving prospects of predicting impact on crop yields. This is particularly important for semi-arid West Africa where climate variability and drought threaten food security. Translating GCM outputs into attainable crop yields is difficult because GCM grid boxes are of larger scale than the processes governing yield, involving partitioning of rain among runoff, evaporation, transpiration, drainage and storage at plot scale. It therefore requires the use of downscaling methods. This study analyzes the performance of both dynamical and statistical downscaling techniques in simulating crop yield at local scale. A detailed case study is conducted using historical weather data for Senegal, applied to the crop model SARRAH for simulating several tropical cereals (sorghum, millet, maize) at local scale. This control simulation is used as a benchmark to evaluate a set of Regional Climate Models (RCM) simulations, forced by ERA-Interim, from the ENSEMBLES project and a statistical downscaling method, the CDF-Transform, used to correct biases in RCM outputs. We first evaluate each climate variable that drives the simulated yield in the control simulation (radiation, rainfall, temperatures). We then simulate crop yields with RCM outputs (with or without applying the CDG-Transform) and evaluate the performance of each RCM in regards to crop yield simulations.

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

    PubMed

    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.

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

    NASA Astrophysics Data System (ADS)

    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.

  15. Deciphering Dynamics of Recent Epidemic Spread and Outbreak in West Africa: The Case of Ebola Virus

    NASA Astrophysics Data System (ADS)

    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.

  16. Reproductive characteristics of Mastomys natalensis and Lassa virus prevalence in Guinea, West Africa.

    PubMed

    Fichet-Calvet, Elisabeth; Lecompte, Emilie; Koivogui, Lamine; Daffis, Stéphane; ter Meulen, Jan

    2008-01-01

    We recently reported increased prevalence of Lassa virus (LASV) infection in Mastomys natalensis during the rainy season in Guinea, West Africa. Here, the association of LASV prevalence with fecundity, fertility, and the age structure of the rodent population was analyzed using data from the previous study. The animals reproduced throughout the year, but highest fecundity was observed during the rainy season. Accordingly, the rodent population was aged at the beginning and young at the end of the rainy season. Lassa virus infection was observed in all age groups, including the very young, which is compatible with vertical transmission. However, since the prevalence of infection showed a trend with increasing age in the younger age groups, horizontal transmission by yet unknown mechanisms may also play a role in LASV transmission. Multivariate analysis did not show an association of LASV prevalence with any demographic variable studied. Rodent behavior influencing virus transmissibility and contaminated environment may therefore be responsible for spatial and seasonal variations in LASV prevalence in M. natalensis.

  17. Water and carbon fluxes from savanna ecosystems of the Volta River watershed, West Africa

    NASA Astrophysics Data System (ADS)

    Freitag, Heiko; Ferguson, Paul R.; Dubois, Kristal; Hayford, Ebenezer Kofi; von Vordzogbe, Vincent; Veizer, Ján

    2008-03-01

    The fluxes of water and carbon from terrestrial ecosystems are coupled via the process of photosynthesis. Constraining the annual water cycle therefore allows first order estimates of annual photosynthetic carbon flux, providing that the components of evapotranspiration can be separated. In this study, an isotope mass-balance equation is utilized to constrain annual evaporation flux, which in turn, is used to determine the amount of water transferred to the atmosphere by plant transpiration. The Volta River watershed in West Africa is dominated by woodland and savanna ecosystems with a significant proportion of C 4 vegetation. Annually, the Volta watershed receives ˜ 380 km 3 of rainfall, ˜ 50% of which is returned to the atmosphere via transpiration. An annual photosynthetic carbon flux of ˜ 170 × 10 12 g C yr - 1 or ˜ 428 g C m - 2 was estimated to be associated with this water vapor flux. Independent estimates of heterotrophic soil respiration slightly exceeded the NPP estimate from this study, implying that the exchange of carbon between the Volta River watershed and the atmosphere was close to being in balance or that terrestrial ecosystems were a small annual source of CO 2 to the atmosphere. In addition to terrestrial carbon flux, the balance of photosynthesis and respiration in Volta Lake was also examined. The lake was found to evade carbon dioxide to the atmosphere although the magnitude of the flux was much smaller than that of the terrestrial ecosystems.

  18. Estimating trends in the total fertility rate with uncertainty using imperfect data: Examples from West Africa

    PubMed Central

    Alkema, Leontine; Raftery, Adrian E.; Gerland, Patrick; Clark, Samuel J.; Pelletier, François

    2013-01-01

    Background Estimating the total fertility rate is challenging for many developing countries because of limited data and varying data quality. A standardized, reproducible approach to produce estimates that include an uncertainty assessment is desired. Methods We develop a method to estimate and assess uncertainty in the total fertility rate over time, based on multiple imperfect observations from different data sources, including surveys and censuses. We take account of measurement error in observations by decomposing it into bias and variance, and assess both by linear regression on a variety of data quality covariates. We estimate the total fertility rate using a local smoother, and assess uncertainty using the weighted likelihood bootstrap. Results We apply our method to data from seven countries in West Africa and construct estimates and uncertainty intervals for the total fertility rate. Based on cross-validation exercises, we find that accounting for differences in data quality between observations gives better calibrated confidence intervals and reduces bias. Conclusions When working with multiple imperfect observations from different data sources to estimate the total fertility rate, or demographic indicators in general, potential biases and differences in error variance should be taken into account to improve the estimates and their uncertainty assessment. PMID:24273449

  19. Natural enemies of the maize cob borer, Mussidia nigrivenella (Lepidoptera: Pyralidae) in Benin, West Africa.

    PubMed

    Sétamou, M; Schulthess, F; Goergen, G; Poehling, H-M; Borgemeister, C

    2002-08-01

    Mussidia nigrivenella Ragonot is a pest of maize cobs in West Africa. It significantly reduces maize yields and grain quality, with quantitative losses of 2-25%at harvest, and up to 10-15% indirect losses due to an increase in storage pest infestation levels. Infestation by M. nigrivenella also significantly increased the susceptibility of maize to Aspergillus flavus infection and subsequent aflatoxin contamination. Surveys conducted in different agro-ecological zones of Benin on cultivated and wild host plants during 1994-1997 revealed one egg parasitoid, three larval parasitoids and one pupal parasitoid attacking M. nigrivenella. Egg parasitism was scarce on all host plants sampled and in all four agro-ecological zones. Parasitism by larval and pupal parasitoids was usually less than 10%, and varied with host plant species. Both larval and pupal parasitoids were rare or absent in cultivated maize fields. The solitary chalcidid pupal parasitoid, Antrocephalus crassipes Masi, was the predominant species, contributing approximately 53% of the observed mortality. Logistic regression analysis indicated that this parasitoid was more prevalent on fruits of Gardenia spp. (Rubiaceae) than on the other host plant species including maize used by M. nigrivenella, and was most abundant between February and September. The differences in parasitoid diversity and parasitism between Benin and other regions suggest that there are opportunities for biological control through introduction of exotic parasitoids or using the 'new association' approach, which uses natural enemies of closely related host species that occupy similar ecological niches to the target pest.

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

    PubMed Central

    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

  1. Occurrence of Emerging Micropollutants in Water Systems in Gauteng, Mpumalanga, and North West Provinces, South Africa

    PubMed Central

    Wanda, Elijah M. M.; Nyoni, Hlengilizwe; Mamba, Bhekie B.; Msagati, Titus A. M.

    2017-01-01

    The ubiquitous occurrence of emerging micropollutants (EMPs) in water is an issue of growing environmental-health concern worldwide. However, there remains a paucity of data regarding their levels and occurrence in water. This study determined the occurrence of EMPs namely: carbamazepine (CBZ), galaxolide (HHCB), caffeine (CAF), tonalide (AHTN), 4-nonylphenol (NP), and bisphenol A (BPA) in water from Gauteng, Mpumalanga, and North West provinces, South Africa using comprehensive two-dimensional gas chromatography coupled to high resolution time-of-flight mass spectrometry (GCxGC-HRTOFMS). Kruskal-Wallis test and ANOVA were performed to determine temporal variations in occurrence of the EMPs. Principal component analysis (PCA) and Surfer Golden Graphics software for surface mapping were used to determine spatial variations in levels and occurrence of the EMPs. The mean levels ranged from 11.22 ± 18.8 ng/L for CAF to 158.49 ± 662 ng/L for HHCB. There was no evidence of statistically significant temporal variations in occurrence of EMPs in water. Nevertheless, their levels and occurrence vary spatially and are a function of two principal components (PCs, PC1 and PC2) which controlled 89.99% of the variance. BPA was the most widely distributed EMP, which was present in 62% of the water samples. The detected EMPs pose ecotoxicological risks in water samples, especially those from Mpumalanga province. PMID:28098799

  2. Poverty, health and satellite-derived vegetation indices: their inter-spatial relationship in West Africa.

    PubMed

    Sedda, Luigi; Tatem, Andrew J; Morley, David W; Atkinson, Peter M; Wardrop, Nicola A; Pezzulo, Carla; Sorichetta, Alessandro; Kuleszo, Joanna; Rogers, David J

    2015-03-01

    Previous analyses have shown the individual correlations between poverty, health and satellite-derived vegetation indices such as the normalized difference vegetation index (NDVI). However, generally these analyses did not explore the statistical interconnections between poverty, health outcomes and NDVI. In this research aspatial methods (principal component analysis) and spatial models (variography, factorial kriging and cokriging) were applied to investigate the correlations and spatial relationships between intensity of poverty, health (expressed as child mortality and undernutrition), and NDVI for a large area of West Africa. This research showed that the intensity of poverty (and hence child mortality and nutrition) varies inversely with NDVI. From the spatial point-of-view, similarities in the spatial variation of intensity of poverty and NDVI were found. These results highlight the utility of satellite-based metrics for poverty models including health and ecological components and, in general for large scale analysis, estimation and optimisation of multidimensional poverty metrics. However, it also stresses the need for further studies on the causes of the association between NDVI, health and poverty. Once these relationships are confirmed and better understood, the presence of this ecological component in poverty metrics has the potential to facilitate the analysis of the impacts of climate change on the rural populations afflicted by poverty and child mortality. © The Author 2015. Published by Oxford University Press on behalf of Royal Society of Tropical Medicine and Hygiene. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

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

    PubMed

    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. Groundwater arsenic contamination in Burkina Faso, West Africa: Predicting and verifying regions at risk.

    PubMed

    Bretzler, Anja; Lalanne, Franck; Nikiema, Julien; Podgorski, Joel; Pfenninger, Numa; Berg, Michael; Schirmer, Mario

    2017-04-15

    Arsenic contamination in groundwater from crystalline basement rocks in West Africa has only been documented in isolated areas and presents a serious health threat in a region already facing multiple challenges related to water quality and scarcity. We present a comprehensive dataset of arsenic concentrations from drinking water wells in rural Burkina Faso (n=1498), of which 14.6% are above 10μg/L. Included in this dataset are 269 new samples from regions where no published water quality data existed. We used multivariate logistic regression with arsenic measurements as calibration data and maps of geology and mineral deposits as independent predictor variables to create arsenic prediction models at concentration thresholds of 5, 10 and 50μg/L. These hazard maps delineate areas vulnerable to groundwater arsenic contamination in Burkina Faso. Bedrock composed of schists and volcanic rocks of the Birimian formation, potentially harbouring arsenic-containing sulphide minerals, has the highest probability of yielding groundwater arsenic concentrations >10μg/L. Combined with population density estimates, the arsenic prediction models indicate that ~560,000 people are potentially exposed to arsenic-contaminated groundwater in Burkina Faso. The same arsenic-bearing geological formations that are positive predictors for elevated arsenic concentrations in Burkina Faso also exist in neighbouring countries such as Mali, Ghana and Ivory Coast. This study's results are thus of transboundary relevance and can act as a trigger for targeted water quality surveys and mitigation efforts.

  5. Oxygen, hydrogen, and helium isotopes for investigating groundwater systems of the Cape Verde Islands, West Africa

    USGS Publications Warehouse

    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. Intraseasonal variability of low-level moisture transport over West Africa

    NASA Astrophysics Data System (ADS)

    Lélé, M. Issa; Leslie, Lance M.

    2016-12-01

    The vertically integrated surface-850 hPa atmospheric water vapor flux is investigated, to account for the total low-level moisture flux contribution to rainfall over West Africa (WA), based on NCEP-NCAR reanalysis data. The focus is the contributions to total moisture transport and convergence by the mean circulation, the synoptic (<10 days), and climate (>10 day) scale anomalies. For WA, the time-mean flow and climate anomalies are comparable. Similarly, for meridional and zonal components, transports by the time-mean and climate anomalies are the largest contributors to mean meridional and zonal moisture transport. While the climate anomalies are responsible for driving moisture poleward from the Atlantic Ocean to the Guinea coast, and westward from the western Atlantic Ocean into the Sahel, the synoptic anomalies contribute to transporting moisture zonally out of the Sahel. Moreover, the spatial distribution of moisture flux convergence reveals a close similarity to the observed 2005 relatively wet and 2006 relatively dry accumulative rainfall. Convergence in WA is mainly the result of moisture transport by the mean flow. An enhanced (weak) flux convergence by the mean flow is characteristic of wet (dry) Sahel rainfall seasons. During wet April-June rainy seasons in the Guinea coast, enhanced convergence due to synoptic anomalies is observed in the region, whereas it is suppressed during dry April-June seasons. In the Sahel, however, during the dry rainy seasons, the convergence region due to synoptic anomalies is displaced southward.

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

    PubMed

    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. Intercomparison of Evapotranspiration Over the Savannah Volta Basin in West Africa Using Remote Sensing Data

    PubMed Central

    Opoku-Duah, S.; Donoghue, D.N.M.; Burt, T. P.

    2008-01-01

    This paper compares evapotranspiration estimates from two complementary satellite sensors – NASA's Moderate Resolution Imaging Spectroradiometer (MODIS) and ESA's ENVISAT Advanced Along-Track Scanning Radiometer (AATSR) over the savannah area of the Volta basin in West Africa. This was achieved through solving for evapotranspiration on the basis of the regional energy balance equation, which was computationally-driven by the Surface Energy Balance Algorithm for Land algorithm (SEBAL). The results showed that both sensors are potentially good sources of evapotranspiration estimates over large heterogeneous landscapes. The MODIS sensor measured daily evapotranspiration reasonably well with a strong spatial correlation (R2=0.71) with Landsat ETM+ but underperformed with deviations up to ∼2.0 mm day-1, when compared with local eddy correlation observations and the Penman-Monteith method mainly because of scale mismatch. The AATSR sensor produced much poorer correlations (R2=0.13) with Landsat ETM+ and conventional ET methods also because of differences in atmospheric correction and sensor calibration over land. PMID:27879847

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

    SciTech Connect

    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}.

  10. Environmental and occupational health needs assessment in West Africa: opportunities for research and training.

    PubMed

    Sanyang, Edrisa; Butler-Dawson, Jaime; Mikulski, Marek A; Cook, Thomas; Kuye, Rex A; Venzke, Kristina; Fuortes, Laurence J

    2017-03-01

    Data are lacking on environmental and occupational health risks and resources available for the prevention of related diseases in the West African subregion. A needs assessment survey was conducted to identify environmental and occupational health concerns, and needs and strategies for skills training in the region. The survey was followed by a consensus-building workshop to discuss research and training priorities with representatives from countries participating in the study. Two hundred and two respondents from 12 countries participated in the survey. Vector-borne diseases, solid waste, deforestation, surface and ground water contamination together with work-related stress, occupational injury and pesticide toxicity were ranked as top environmental and occupational health priorities, respectively, in the region. Top training priorities included occupational health, environmental toxicology and analytic laboratory techniques with semester-long Africa-based courses as the preferred type of training for the majority of the courses. Major differences were found between the subregion's three official language groups, both in perceived health risks and training courses needed. The study results have implications for regional policies and practice in the area of environmental and occupational health research and training.

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

    NASA Astrophysics Data System (ADS)

    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.

  12. Healthcare in Equatorial Guinea, West Africa: obstacles and barriers to care

    PubMed Central

    Reuter, Kim Eleanor; Geysimonyan, Aurora; Molina, Gabriela; Reuter, Peter Robert

    2014-01-01

    Introduction The provision of healthcare services in developing countries has received increasing attention, but inequalities persist. One nation with potential inequalities in healthcare services is Equatorial Guinea (Central-West Africa). Mitigating these inequalities is difficult, as the Equatoguinean healthcare system remains relatively understudied. Methods In this study, we interviewed members of the healthcare community in order to: 1) learn which diseases are most common and the most common cause of death from the perspective of healthcare workers; and 2) gain an understanding of the healthcare community in Equatorial Guinea by describing how: a) healthcare workers gain their professional knowledge; b) summarizing ongoing healthcare programs aimed at the general public; c) discussing conflicts within the healthcare community and between the public and healthcare providers; d) and addressing opportunities to improve healthcare delivery. Results We found that some causes of death, such as serious injuries, may not be currently treatable in country, potentially due to a lack of resources and trauma care facilities. In addition, training and informational programs for both healthcare workers and the general public may not be effectively transmitting information to the intended recipients. This presents hurdles to the healthcare community, both in terms of having professional competence in healthcare delivery and in having a community that is receptive to medical care. Conclusion Our data also highlight government-facility communication as an opportunity for improvement. Our research is an important first step in understanding the context of healthcare delivery in Equatorial Guinea, a country that is relatively data poor. PMID:25932082

  13. Mining and environmental change in Sierra Leone, West Africa: a remote sensing and hydrogeomorphological study.

    PubMed

    Akiwumi, Fenda A; Butler, David R

    2008-07-01

    This paper evaluates the environmental changes in southwestern Sierra Leone, West Africa from rutile (titanium dioxide) between 1967 and 1995. Mining in peripheral parts of the world economy is a consequence of larger global economic interests. Historically, long-distance trade and export production of minerals and other natural resources primarily for the benefit of core countries are responsible for transforming the natural environment and landscapes of peripheral sectors of the world economy. Tracking environmental change in developing countries such as Sierra Leone is challenging because of financial and infrastructural constraints on the use of ground methods of evaluation and monitoring. Remote sensing data are invaluable in assessing the human dimensions of Land Use and Land Cover Change (LULCC) with implications for political ecology. Using available multi-date infrared Landsat images supplemented with field hydrological and biophysical data, we monitored the rapid temporal and spatial dynamic characteristic of mining areas in the study area with a focus on physical changes to the landscape. Reservoir construction for mining has caused flooding of alluvial lowlands, deforestation, and the creation of tailings and stockpiles over mined-out portions of the lease. Although the study was conducted at a local scale, it represents the broad, regional, past-to-present manner by which global economic interests exploit natural resources and impact the environment in distant places.

  14. Intercomparison of Evapotranspiration Over the Savannah Volta Basin in West Africa Using Remote Sensing Data.

    PubMed

    Opoku-Duah, S; Donoghue, D N M; Burt, T P

    2008-04-17

    This paper compares evapotranspiration estimates from two complementary satellite sensors - NASA's Moderate Resolution Imaging Spectroradiometer (MODIS) and ESA's ENVISAT Advanced Along-Track Scanning Radiometer (AATSR) over the savannah area of the Volta basin in West Africa. This was achieved through solving for evapotranspiration on the basis of the regional energy balance equation, which was computationally-driven by the Surface Energy Balance Algorithm for Land algorithm (SEBAL). The results showed that both sensors are potentially good sources of evapotranspiration estimates over large heterogeneous landscapes. The MODIS sensor measured daily evapotranspiration reasonably well with a strong spatial correlation (R²=0.71) with Landsat ETM+ but underperformed with deviations up to ~2.0 mm day(-1), when compared with local eddy correlation observations and the Penman-Monteith method mainly because of scale mismatch. The AATSR sensor produced much poorer correlations (R²=0.13) with Landsat ETM+ and conventional ET methods also because of differences in atmospheric correction and sensor calibration over land.

  15. Impact of Low Level Clouds on radiative and turbulent surface flux in southern West Africa

    NASA Astrophysics Data System (ADS)

    Lohou, Fabienne; Kalthoff, Norbert; Dione, Cheikh; Lothon, Marie; Adler, Bianca; Babic, Karmen; Pedruzo-Bagazgoitia, Xabier; Vila-Guerau De Arellano, Jordi

    2017-04-01

    During the monsoon season in West Africa, low-level clouds form almost every night and break up between 0900 and the middle of the afternoon depending on the day. The break-up of these clouds leads to the formation of boundary-layer cumuli clouds, which can sometimes evolve into deep convection. The low-level clouds have a strong impact on the radiation and energy budget at the surface and consequently on the humidity in the boundary layer and the afternoon convection. During the DACCIWA ground campaign, which took place in June and July 2016, three supersites in Benin, Ghana, and Nigeria were instrumented to document the conditions within the lower troposphere including the cloud layers. Radiative and turbulent fluxes were measured at different places by several surface stations jointly with low-level cloud occurrence during 50 days. These datasets enable the analysis of modifications in the diurnal cycle of the radiative and turbulent surface flux induced by the formation and presence of the low-level clouds. The final objective of this study is to estimate the error made in some NWP simulations when the diurnal cycle of low-level clouds is poorly represented or not represented at all.

  16. Numerical simulation of convectively generated gravity waves in West Africa and comparisons with observations

    NASA Astrophysics Data System (ADS)

    Heinrich, P.; Blanc, E.

    2012-04-01

    Convective clouds in the ITCZ (Intertropical Convergence Zone) are a major source of nonstationary gravity waves, that propagate to the stratosphere and result in upward displacements at low levels, which induces new convection. Simulations of wind fields are performed by the mesoscale meteorological model WRF (Advanced Research Weather Research and Forecasting) over a period of 2 days during active thunderstorm days. Simulations are carried out in a domain covering the ITCZ in West Africa using 2 nested grids with horizontal grid spacing of 27 and 9 km respectively. Simulations are driven by ECMWF winds (defined by 91 levels from surface to 80 km), using 100 levels from surface to 50 Pa and a sponge layer above 45 km. The waves characteristics are compared to observations at the CTBT (Comprehensive Test Ban Treaty) infrasound station in Ivory Coast. The aim of this study is to further understand the mechanisms of wave generation by deep convection and propagation to the stratosphere. In a second part, we also study the effects of gravity waves on the dynamics of the tropical atmosphere and perform sensitivity simulations to the top height of the model.

  17. Distinguishing epidemiological features of the 2013–2016 West Africa Ebola virus disease outbreak

    PubMed Central

    Shultz, James M.; Espinel, Zelde; Espinola, Maria; Rechkemmer, Andreas

    2016-01-01

    ABSTRACT The 2013–2016 West Africa Ebola virus disease epidemic was notable for its scope, scale, and complexity. This briefing presents a series of distinguishing epidemiological features that set this outbreak apart. Compared to one concurrent and 23 previous outbreaks of the disease over 40 years, this was the only occurrence of Ebola virus disease involving multiple nations and qualifying as a pandemic. Across multiple measures of magnitude, the 2013–2016 outbreak was accurately described using superlatives: largest and deadliest in terms of numbers of cases and fatalities; longest in duration; and most widely dispersed geographically, with outbreak-associated cases occurring in 10 nations. In contrast, the case-fatality rate was much lower for the 2013–2016 outbreak compared to the other 24 outbreaks. A population of particular interest for ongoing monitoring and public health surveillance is comprised of more than 17,000 “survivors,” Ebola patients who successfully recovered from their illness. The daunting challenges posed by this outbreak were met by an intensive international public health response. The near-exponential rate of increase of incident Ebola cases during mid-2014 was successfully slowed, reversed, and finally halted through the application of multiple disease containment and intervention strategies. PMID:28229017

  18. Surface properties in West Africa from spaceborne radars in C and Ku bands

    NASA Astrophysics Data System (ADS)

    Fatras, Christophe; Frappart, Frédéric; Mougin, Eric; Frison, Pierre-Louis; Faye, Gayane; Jarlan, Lionel

    2013-04-01

    We propose to compare the backscattering responses of land surfaces in West Africa for different radar spaceborne sensors: the nadir-looking radar altimeters and the side-looking radar scatterometers at different frequencies (Ku and C bands). The data used come from Envisat-RA2 measurements in Ku-band over the period 2003-2010 and the Jason-2 measurements in C band over mid-2008-2011 for radar altimetry, and from QuikSCAT - SeaWinds in Ku-band and Metop - ASCAT in C-band for radar scatterometry over the same time-spans. Along-track profiles and their temporal variations are analyzed and their behaviours are related to surfaces properties such as soil types, vegetation cover, and surface hydrology. Temporal variations of backscattering coefficients are extracted for main land covers along the bio-climatic transect (stone and sand deserts, saharo-sahelian, sahelian, and soudano-sahelian savannahs, tropical-seasonal and tropical forests) and compared to both rainfall estimates from TRMM and vegetation activity (NDVI) from MODIS. Range of variations of the backscattering signals are given for different surfaces and ecosystems along with delays between peaks of rainfall, backscattering responses of radar altimetry and scatterometry, and vegetation activity. The stability of the backscattering is also estimated over deserts and during the dry season over Sahelian environments. Finally, the complementarity of the different spaceborne sensors for continental surfaces monitoring is pointed out.

  19. Value of phage typing of Vibrio cholerae biotype eltor in West Africa*

    PubMed Central

    Bockemühl, J.; Meinicke, D.

    1976-01-01

    The epidemiological value of phage typing of El Tor vibrios in West Africa was assessed by testing 211 representative strains from all outbreaks of the cholera epidemic in Togo (1970-73) with the prophage typing method of Nicolle et al. and the lytic El Tor phages of Basu & Mukerjee. Prophage typing proved to be of limited epidemiological value in Togo since 203 of the 211 strains tested belonged to the same phage type—namely, type 2 of Nicolle et al., which corresponds to the Celebes type of Takeya. Six strains belonged to type 1, 1 strain to type 4, and 1 strain was untypable. Tested by the lytic El Tor phages, 175 strains were found to belong to type 4 of Basu & Mukerjee, 35 strains to type 1, and 1 strain was untypable. All but two strains of type 1 were isolated from 3 outbreaks in which this phage type was found almost exclusively. The results are in good agreement with epidemiological data collected during the epidemic. El Tor phage V reacted with a specificity of over 99% when tested against 601 strains of El Tor and NCV vibrios from Togo and may be recommended for the rapid identification of El Tor vibrios. PMID:1088101

  20. Practices and thinking of laboratory detection in the aid to West Africa to fight against Ebola.

    PubMed

    Sun, Y S; Zhao, X Y; Zhang, B K; Jiang, J F; Lu, H J; Cao, Y X; Wu, G Z; Qian, J; Sun, Y S; Zeng, Y J

    2016-01-01

    The outbreak of Ebola virus disease in West Africa has brought great disaster to the people's health in affected countries. China dispatched first group of public health experts and medical staff to Sierra Leone in September 2014 to fight Ebola. To systematically collect huge amount of primary data, and to make analysis, draw conclusions and lessons in terms of six aspects, respectively as training before departure, local disease information, track of epidemic situation, transformation of temporary laboratory, detection of Ebola virus samples as well as assessment through single blind test. 1) Our team has launched preparatory works in advance before going to Sierra Leone. 2) Malaria is the country's severest infectious disease. 3) Observation centers were overcrowded with large number of suspected cases being inspected, implying high risk of nosocomial infection. 4) A BSL-II laboratory with 3 work areas and 2 buffer areas was built, achieving several major functions within 6 days. 5) Confirmed by South African Raqqa laboratory, our detection accuracy reached 100%. 6) At one week before return, the daily average sample amount of our team reached 66 cases and our detection capability was equivalent to that of USA. Successful experience from fighting against Ebola in Sierra Leone could be summarized as: 1) Optimized processes and scientific security measures are prerequisite to improving the detection ability. 2) The close collaboration between laboratory and observation center has created a new model of China's foreign aid. 3) Comprehensive information investigation and training lay a solid foundation for the successful completion of tasks.

  1. Simulation of Subseasonal Characteristics of Rainfall in Central West Africa using a Hidden Markov Model.

    NASA Astrophysics Data System (ADS)

    Trzaska, S.; Robertson, A. W.; Dibi-Kangah, P.

    2006-05-01

    One of the major challenges in translating General Circulation Model (GCM) outputs, such as seasonal forecasts, to meet societal needs is that the potential users of climate information are often concerned with the characteristics of high-frequency weather at a particular location. Unfortunately such statistics of local weather are poorly represented in GCMs due to limits in predictability horizon and resolution. Here we present results obtained using a Hidden Markov Model (HMM) as a diagnostic and downscaling tool. The basic assumption underlying this technique is that multistation daily rainfall observations can be well described in terms of a few underlying (hidden) weather states, with a Markovian dependence in time. It can thus be used: first, to diagnose the weather patterns associated with rainfall variability at the station level and simulate associated weather/circulation patterns sequence; second, to downscale GCM outputs to the daily rainfall at station level. For downscaling purposes the HMM are extended to the so-called non homogeneous HMM (NHMM) where state-transition probabilities are allowed to vary in time. The present study focuses on Central West Africa (Cote d'Ivoire, Burkina Faso, Mali) and uses daily rainfall data from a network of ca 40 stations, the NCEP reanalysis and GCM outputs over the period 1950-1998. Sensitivity of the method to the use of different exogenous forcing parameters as well as to the number of stations and area covered will be discussed.

  2. Physiological Evaluation of Personal Protective Ensembles Recommended for Use in West Africa.

    PubMed

    Coca, Aitor; Quinn, Tyler; Kim, Jung-Hyun; Wu, Tianzhou; Powell, Jeff; Roberge, Raymond; Shaffer, Ronald

    2017-03-17

    Personal protective equipment (PPE) provides health care workers with a barrier to prevent human contact with viruses like Ebola and potential transmission of the disease. However, PPE can also introduce an additional physiological burden from potentially increased heat stress. This study evaluated the human physiological and subjective responses to continuous light exercise within environmental conditions similar to those in West Africa while wearing 3 different, commonly used PPE ensembles (E1, E2, and E3). Six healthy individuals were tested in an environmental chamber (32°C, 92% relative humidity) while walking (3 METs, 2.5 mph, 0% incline) on a treadmill for 60 minutes. All subjects wore medical scrubs and PPE items. E1 also had a face shield and fluid-resistant surgical gown; E2 additionally included goggles, coverall, and separate hood; and E3 also contained a highly impermeable coverall, separate hood, and surgical mask cover over the N95 respirator. Heart rate and core temperature at the end of the exercise were significantly higher for E2 and E3 than for E1. Subjective perceptions of heat and exertion were significantly higher for E2 and E3 than for E1. Heat stress and PPE training, as well as the implementation of a work-to-rest ratio that avoids dehydration and possible heat stress issues, are recommended. (Disaster Med Public Health Preparedness. 2017;page 1 of 7).

  3. Ocular manifestations of onchocerciasis in a rain forest area of west Africa.

    PubMed Central

    Newland, H S; White, A T; Greene, B M; Murphy, R P; Taylor, H R

    1991-01-01

    The epidemiology and natural history of onchocerciasis and its ocular complications in rain forest areas are poorly understood. The present study was conducted on a rubber plantation in a hyperendemic area in the rain forest of Liberia, West Africa, where 800 persons were examined. The prevalence of infection was 84% overall 29% had intraocular microfilariae, and 2.4% were blind in one or both eyes. Onchocerciasis was the cause of all binocular blindness and one-third of all visual impairment. Over half of the visual impairment caused by onchocerciasis was due to posterior segment diseases. Chorioretinal changes were present in 75% of people, and included intraretinal pigment clumping in 52% and retinal pigment epithelium atrophy in 32%. Atrophy of the retinal pigment epithelium was associated with increasing age and severity of infection. Intraretinal pigment was strongly associated with anterior uveitis. There was a strong correlation between uveitis and the inflammatory chorioretinal sequelae: retinitis, intraretinal pigment, subretinal fibrosis, and optic neuropathy. These findings indicate that considerable visual impairment associated with rain forest onchocerciasis is common and is due largely to chorioretinal disease. Images PMID:2012784

  4. Insularity effects on bird immune parameters: A comparison between island and mainland populations in West Africa.

    PubMed

    Lobato, Elisa; Doutrelant, Claire; Melo, Martim; Reis, Sandra; Covas, Rita

    2017-06-01

    Oceanic islands share several environmental characteristics that have been shown to drive convergent evolutionary changes in island organisms. One change that is often assumed but has seldom been examined is the evolution of weaker immune systems in island species. The reduction in species richness on islands is expected to lead to a reduced parasite pressure and, given that immune function is costly, island animals should show a reduced immune response. However, alternative hypotheses exist; for example, the slower pace of life on islands could favor the reorganization of the immune system components (innate vs. acquired immunity) on islands. Thus far, few island species have been studied and no general patterns have emerged. Here, we compared two immune parameters of birds from São Tomé and Príncipe islands to those of their close relatives at similar latitudes on the mainland (Gabon, West Africa). On islands, the acquired humoral component (total immunoglobulins) was lower for most species, whereas no clear pattern was detected for the innate component (haptoglobin levels). These different responses did not seem to arise from a reorganization of the two immune components, as both total immunoglobulins and haptoglobin levels were positively associated. This work adds to the few empirical studies conducted so far which suggest that changes in immune parameters in response to insularity are not as straightforward as initially thought.

  5. Healthcare in Equatorial Guinea, West Africa: obstacles and barriers to care.

    PubMed

    Reuter, Kim Eleanor; Geysimonyan, Aurora; Molina, Gabriela; Reuter, Peter Robert

    2014-01-01

    The provision of healthcare services in developing countries has received increasing attention, but inequalities persist. One nation with potential inequalities in healthcare services is Equatorial Guinea (Central-West Africa). Mitigating these inequalities is difficult, as the Equatoguinean healthcare system remains relatively understudied. In this study, we interviewed members of the healthcare community in order to: 1) learn which diseases are most common and the most common cause of death from the perspective of healthcare workers; and 2) gain an understanding of the healthcare community in Equatorial Guinea by describing how: a) healthcare workers gain their professional knowledge; b) summarizing ongoing healthcare programs aimed at the general public; c) discussing conflicts within the healthcare community and between the public and healthcare providers; d) and addressing opportunities to improve healthcare delivery. We found that some causes of death, such as serious injuries, may not be currently treatable in country, potentially due to a lack of resources and trauma care facilities. In addition, training and informational programs for both healthcare workers and the general public may not be effectively transmitting information to the intended recipients. This presents hurdles to the healthcare community, both in terms of having professional competence in healthcare delivery and in having a community that is receptive to medical care. Our data also highlight government-facility communication as an opportunity for improvement. Our research is an important first step in understanding the context of healthcare delivery in Equatorial Guinea, a country that is relatively data poor.

  6. Aircraft measurements of biomass burning aerosol over West Africa during DABEX

    NASA Astrophysics Data System (ADS)

    Johnson, B. T.; Osborne, S. R.; Haywood, J. M.; Harrison, M. A. J.

    2008-12-01

    This paper investigates the properties of biomass burning aerosols over West Africa using data from the UK FAAM aircraft during the Dust and Biomass-burning Experiment (DABEX). Aged biomass burning aerosols were widespread across the region, often at altitudes up to 4 km. Fresh biomass burning aerosols were observed at low altitudes by flying through smoke plumes from agricultural fires. The aircraft measured aerosol size distributions, optical properties, and vertical distributions. Single scattering albedo varied from 0.73 to 0.93 (at 0.55 μm) in aerosol layers dominated by biomass burning aerosol. We attribute much of this variation to the variable proportion of mineral dust and biomass burning aerosol. We estimate the single scattering albedo of aged biomass burning aerosol to be around 0.81 with an instrumental uncertainty of ±0.05. External mixing, and possibly internal mixing, between the biomass burning aerosol and mineral dust presents an additional source of uncertainty in this estimate. The size distributions of biomass burning aerosols were dominated by particles with radii smaller than 0.35 μm. A 20% increase of count mean radius was observed when contrasting fresh and aged biomass burning aerosols, accompanied by changes in the shape of the size distribution. These changes suggest growth by coagulation and condensation. Extinction coefficients, asymmetry parameters, and Angstrom exponents are calculated from Mie theory, using the lognormal fits to the measured size distributions and assumed refractive indices.

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

    NASA Astrophysics Data System (ADS)

    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.

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

    PubMed

    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.

  9. An evaluability assessment of a West Africa based Non-Governmental Organization's (NGO) progressive evaluation strategy.

    PubMed

    D'Ostie-Racine, Léna; Dagenais, Christian; Ridde, Valéry

    2013-02-01

    While program evaluations are increasingly valued by international organizations to inform practices and public policies, actual evaluation use (EU) in such contexts is inconsistent. Moreover, empirical literature on EU in the context of humanitarian Non-Governmental Organizations (NGOs) is very limited. The current article focuses on the evaluability assessment (EA) of a West-Africa based humanitarian NGO's progressive evaluation strategy. Since 2007, the NGO has established an evaluation strategy to inform its maternal and child health care user-fee exemption intervention. Using Wholey's (2004) framework, the current EA enabled us to clarify with the NGO's evaluation partners the intent of their evaluation strategy and to design its program logic model. The EA ascertained the plausibility of the evaluation strategy's objectives, the accessibility of relevant data, and the utility for intended users of evaluating both the evaluation strategy and the conditions that foster EU. Hence, key evaluability conditions for an EU study were assured. This article provides an example of EA procedures when such guidance is scant in the literature. It also offers an opportunity to analyze critically the use of EAs in the context of a humanitarian NGO's collaboration with evaluators and political actors.

  10. Suitability Evaluation for Lowland Rice in Inland Valleys in West Africa

    NASA Astrophysics Data System (ADS)

    Hideto, Fujii; Muralikrishna, Gumma; Prasad, Thenkabail; Regassa, Namara

    A GIS based model developed by the authors are applied for selecting suitable rice cultivation area in inland valleys that has high potential for rice production in West Africa where rice consumption is increasing very rapidly. The model has the following features. 1) The model is to evaluate the suitability of the land for lowland rice based on score distribution maps respectively made by the data of 29 evaluation parameters. 2) The parameters are classified into 4 categories; bio-physical, technical, socio-economic and health-environmental parameters. 3) Each scored map (layer) is integrated to obtain total scores by multiplying a weight which is determined by the importance of parameters. The suitability for rice in two study sites was evaluated using the model. Mankran and Jolo-Kwaha watershed selected as the study sites from different agro-ecological zone in Ghana. Applying the data of 12 parameters acquired in the study sites to the model, “very suitable” or “suitable” occupies around 30% in Mankran study site and around 60% in Jolo-Kwaha study site.

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

    PubMed

    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.

  12. Genetic structure and mating system of wild cowpea populations in West Africa

    PubMed Central

    2012-01-01

    Background Cowpea is a highly inbred crop. It is part of a crop-weed complex, whose origin and dynamics is unknown, which is distributed across the African continent. This study examined outcrossing rates and genetic structures in 35 wild cowpea (Vigna unguiculata ssp. unguiculata var. spontanea) populations from West Africa, using 21 isozyme loci, 9 of them showing polymorphism. Results Outcrossing rates ranged from 1% to 9.5% (mean 3.4%), which classifies the wild cowpea breeding system as primarily selfing, though rare outcrossing events were detected in each population studied. Furthermore, the analyses of both the genetic structure of populations and the relationships between the wild and domesticated groups suggest possibilities of gene flow that are corroborated by field observations. Conclusions As expected in a predominantly inbred breeding system, wild cowpea shows high levels of genetic differentiation and low levels of genetic diversity within populations. Gene flow from domesticated to wild cowpea does occur, although the lack of strong genetic swamping and modified seed morphology in the wild populations suggest that these introgressions should be rare. PMID:22827925

  13. Occurrence of Emerging Micropollutants in Water Systems in Gauteng, Mpumalanga, and North West Provinces, South Africa.

    PubMed

    Wanda, Elijah M M; Nyoni, Hlengilizwe; Mamba, Bhekie B; Msagati, Titus A M

    2017-01-13

    The ubiquitous occurrence of emerging micropollutants (EMPs) in water is an issue of growing environmental-health concern worldwide. However, there remains a paucity of data regarding their levels and occurrence in water. This study determined the occurrence of EMPs namely: carbamazepine (CBZ), galaxolide (HHCB), caffeine (CAF), tonalide (AHTN), 4-nonylphenol (NP), and bisphenol A (BPA) in water from Gauteng, Mpumalanga, and North West provinces, South Africa using comprehensive two-dimensional gas chromatography coupled to high resolution time-of-flight mass spectrometry (GCxGC-HRTOFMS). Kruskal-Wallis test and ANOVA were performed to determine temporal variations in occurrence of the EMPs. Principal component analysis (PCA) and Surfer Golden Graphics software for surface mapping were used to determine spatial variations in levels and occurrence of the EMPs. The mean levels ranged from 11.22 ± 18.8 ng/L for CAF to 158.49 ± 662 ng/L for HHCB. There was no evidence of statistically significant temporal variations in occurrence of EMPs in water. Nevertheless, their levels and occurrence vary spatially and are a function of two principal components (PCs, PC1 and PC2) which controlled 89.99% of the variance. BPA was the most widely distributed EMP, which was present in 62% of the water samples. The detected EMPs pose ecotoxicological risks in water samples, especially those from Mpumalanga province.

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

    USGS Publications Warehouse

    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.

  15. Regional-scale climate-variability synchrony of cholera epidemics in West Africa

    PubMed Central

    Constantin de Magny, Guillaume; Guégan, Jean-François; Petit, Michel; Cazelles, Bernard

    2007-01-01

    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. PMID:17371602

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

    PubMed

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

    2017-01-22

    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.

  17. Oxygen, hydrogen, and helium isotopes for investigating groundwater systems of the Cape Verde Islands, West Africa

    NASA Astrophysics Data System (ADS)

    Heilweil, Victor M.; Solomon, D. Kip; Gingerich, Stephen B.; Verstraeten, Ingrid M.

    2009-07-01

    Stable isotopes (δ18O, δ2H), 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 São Nicolau Island’s Ribeira Fajã Basin has groundwater residence times of more than 50 years, whereas Fogo Island’s Mosteiros Basin and Santo Antão 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.

  18. Masked millennial-scale climate variations in South West Africa during the last glaciation

    NASA Astrophysics Data System (ADS)

    Hessler, I.; Dupont, L.; Handiani, D.; Paul, A.; Merkel, U.; Wefer, G.

    2012-04-01

    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.

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

    NASA Astrophysics Data System (ADS)

    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.

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

    NASA Astrophysics Data System (ADS)

    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.