The prevalence of Plasmodium falciparum in sub-Saharan Africa since 1900.

Malaria transmission is influenced by climate, land use and deliberate interventions. Recent declines have been observed in malaria transmission. Here we show that the African continent has witnessed a long-term decline in the prevalence of Plasmodium falciparum from 40% prevalence in the period 1900-1929 to 24% prevalence in the period 2010-2015, a trend that has been interrupted by periods of rapidly increasing or decreasing transmission. The cycles and trend over the past 115 years are inconsistent with explanations in terms of climate or deliberate intervention alone. Previous global initiatives have had minor impacts on malaria transmission, and a historically unprecedented decline has been observed since 2000. However, there has been little change in the high transmission belt that covers large parts of West and Central Africa. Previous efforts to model the changing patterns of P. falciparum transmission intensity in Africa have been limited to the past 15 years or have used maps drawn from historical expert opinions. We provide quantitative data, from 50,424 surveys at 36,966 geocoded locations, that covers 115 years of malaria history in sub-Saharan Africa; inferring from these data to future trends, we would expect continued reductions in malaria transmission, punctuated with resurgences

EXAMINING THE FACTORS INFLUENCING THE ABUNDANCE AND DISTRIBUTION OF SORGHUM (Sorghum Bicolor [L.] Moench): AN ANALYSIS OF THE WEST SAHEL OF SUB-SAHARAN AFRICA

Sorghum is the fifth most produced crop worldwide, yet despite its exceptional advantages over other major cereals, its inferior reputation and low commercial value have left it under-represented in both research and the international market. The importance of subsistence sorghum calls for targeted research on the local relationships between agriculture and the surrounding environment to establish and quantify the impacts of major players on sorghum output. This three-article style dissertation investigates the major factors that impact sorghum production, with a focus on northern Nigeria in the West Sahel. In the first study I explored the developments in sorghum production within six major producing countries across the globe and identified key factors that have notable effects on overall sorghum production. Next, I employed a time-series analysis to determine the responses in sorghum yield induced by a set of variables in nine northern Nigerian states based on historical trends. Finally, I investigated the association between the spatial distribution of sorghum yield and a separate set of explanatory variables, whilst comparing the results and performance of different spatial multivariate methods. The results revealed ten major influential factors that impact sorghum production within the leading production regions: climate change, agricultural input, population/economic growth, biodiversity, agricultural resource scarcity, other crop demand, price, non-food demand, cultural influence and armed conflict. In northern Nigeria, precipitation, temperature and soil moisture were shown to have substantial temporal and spatial influences on sorghum production. There was also evidence on the important roles played by producer price and genetic variation in the abundance and distribution, respectively, of sorghum production in the study area. These findings imply the need to increase efforts in soil conservation programs and champion the adoption of soil-moisture-dependent masakwa cultivation of sorghum wherever appropriate. Sustaining lucrative producer prices and encouraging the trading of seeds to promote genetic variation are likely to lead to improved sorghum yield in the area. However, the development of policies that bind government and intuitional agencies to the commitment of improvements in farmer welfare would also be critical. Post production support would include: development of better and safe transportation routes to reduce high transportation costs, price stabilization, improved sorghum markets and establishment of local trade associations. Future inquiries can be further focused on more localized investigations that further develop the description of the location–specific variables impacting sorghum production and the nature of their influence on sorghum yield in these vulnerable regions

A Regional Comparison of Factors Affecting Global Sorghum Production: The Case of North America, Asia and Africa’s Sahel

Understanding the dynamics of food production is critical to improving food security. This is particularly important in regions that rely on subsistence agriculture with little adaptive capacity to climate change. Sorghum plays an important role in food security in some of the poorest parts of the world. This article reviews the literature to identify and examine the major factors affecting sorghum production in three major production regions. Factors were not categorized ex ante but rather determined from the review. Ten major factors were identified as having notable impacts on sorghum production: climate change, population growth/economic development, non-food demand, agricultural inputs, demand for other crops, agricultural resources scarcity, biodiversity, cultural influence, price and armed conflict. This synthesis revealed that (1) multiple factors simultaneously affect sorghum production; (2) the effect of each factor is greatly influenced by the magnitude and certainty of one or more other factors; and, (3) factors differ in relevance and degree with regard to geography. Generally, improved agricultural inputs, population growth/economic development and climate change have substantial influence on sorghum production. However, local dynamics likely go beyond these broad trends and more exhaustive, locally-focused studies are needed for actionable planning purposes