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Resistance in Anopheles gambiae to members of all 4 major classes (pyrethroids, carbamates, organochlorines, and organophosphates) of public health insecticides limits effective control of malaria transmission in Africa. Increase in expression of detoxifying enzymes has been associated with insecticide resistance, but their direct functional validation in An. gambiae is still lacking. Here, we perform transgenic analysis using the GAL4/UAS system to examine insecticide resistance phenotypes conferred by increased expression of the 3 genes--Cyp6m2, Cyp6p3, and Gste2--most often found up-regulated in resistant An. gambiae. We report evidence in An. gambiae that organophosphate and organochlorine resistance is conferred by overexpression of GSTE2 in a broad tissue profile. Pyrethroid and carbamate resistance is bestowed by similar Cyp6p3 overexpression, and Cyp6m2 confers only pyrethroid resistance when overexpressed in the same tissues. Conversely, such Cyp6m2 overexpression increases susceptibility to the organophosphate malathion, presumably due to conversion to the more toxic metabolite, malaoxon. No resistant phenotypes are conferred when either Cyp6 gene overexpression is restricted to the midgut or oenocytes, indicating that neither tissue is involved in insecticide resistance mediated by the candidate P450s examined. Validation of genes conferring resistance provides markers to guide control strategies, and the observed negative cross-resistance due to Cyp6m2 gives credence to proposed dual-insecticide strategies to overcome pyrethroid resistance. These transgenic An. gambiae-resistant lines are being used to test the "resistance-breaking" efficacy of active compounds early in their development. [ABSTRACT FROM AUTHOR]

In theory, democratisation, which has proceeded unevenly across Africa during the past two decades, should encourage pro-poor agricultural policy, as the majority of voters in many countries remain rural and poor. This article draws on case studies of recent policy change in six African countries, plus a review of the literature on political competition and voting behaviour, to explore the evolving role of competitive electoral politics in agricultural policy-making. It finds that democratic pressures for pro-poor agricultural policy remain weak, which may help explain the limited delivery thus far on commitments to the Comprehensive Africa Agriculture Development Programme (CAADP). However, exogenous factors - most strikingly, sustained threats to regime survival - can create positive incentives for agricultural investment. The implications for participants in agricultural policy processes are explored. [ABSTRACT FROM AUTHOR]

The Malawi FISP resurrected debates about the role of subsidies in African agricultural policy. Recent literature has highlighted the social and political interests that influence the distribution of input-subsidy vouchers, often tending to reduce the efficiency with which such programmes contribute to poverty reduction. Taking the FISP as a case study, this article examines the political incentives that have driven programme implementation. Two streams of rents associated with the FISP were used to generate support for the first-term government of President Mutharika (2005-9), with very different implications for programme efficiency. One then stopped abruptly in 2009. The Malawi case demonstrates both the importance of political incentives in determining subsidy outcomes and how they can change dramatically over time. [ABSTRACT FROM AUTHOR]

The Agulhas Bank on the tip of southern Africa, like other shelf seas, is a relatively productive environment which plays a crucial role in the biology and success of many commercially valuable fish species. Fish and their larvae depend on zooplankton to feed on but, despite their importance, little is known about zooplankton distribution and production on the Agulhas Bank. Here we present results from a survey conducted in March 2019 on the East and Central Agulhas Bank, investigating mesozooplankton abundance, biovolume, taxonomic composition, size distribution (normalised biovolume size spectrum (NBSS) approach) and secondary production. A clear cross-shore gradient was observed with the inner-shelf having higher abundance and biovolume of mesozooplankton dominated by small-size organisms, most likely mirroring higher overall productivity of the coastal waters, while the outer-shelf showed the opposite trend (i.e. , low abundance and biovolume; shallow NBSS slopes). This general pattern on the outer-shelf was, however, disturbed in one location (between 24 and 25°E) with a distinguishable mesozooplankton community, most likely linked to the passage of a meander on the inshore side of the Agulhas Current. The Central Agulhas Bank was typified by high mesozooplankton biomass (∼4 g C m-2), comparable to upwelling areas and dominated by copepods and doliolids. High copepod biomass was observed in this region before and was linked to a feature called the "Cold Ridge". However, during our survey, no such ridge was observed. The mixed layer depth was relatively deep (>20 m) and high Chlorophyll a concentration was measured at depth, despite low net primary production rates. We suggest that this region is prone to other mechanisms such as retention due to cyclonic circulation or processes injecting nutrients in the upper mixed layer that require further research. Secondary production on the Agulhas Bank was in the same range as other shelf seas (0.03–1.55 g C m-2 d-1) and was correlated with mesozooplankton biomass. The comparison of primary and secondary production, measured simultaneously, suggested that mesozooplankton exert a significant control on net primary production, and can, in some areas, be food-limited (e.g. , Central Agulhas Bank and inshore waters). • Mesozooplankton biomass on the Agulhas Bank in March was 0.1–4.27 g C m-2. • The inner-shelf reveals higher zooplankton biomass and steeper NBSS slopes. • The Central Agulhas Bank has high zooplankton biomass, comparable to upwelling areas. • Secondary production in March ranged from 0.03 to 1.55 g C m-2 d-1. [ABSTRACT FROM AUTHOR]

Abstract: Background: The development of a new, more effective vaccine against tuberculosis (TB) for use in healthy and HIV-infected adults, children and infants, remains a global health priority. MVA85A is a candidate tuberculosis vaccine designed to enhance immunity to the existing vaccine, Bacillus Calmette-Guerin (BCG). MVA85A entered clinical trials in 2002 and has now progressed to Phase IIb proof-of-concept efficacy trials in infants and HIV-infected adults in Africa. Methods: A detailed analysis was conducted of the cumulative safety data of intradermal delivery of MVA85A in 112 healthy adult subjects in a series of open label, single arm, non-controlled, Phase I safety and immunogenicity clinical trials in the UK. The trials differed with respect to previous mycobacterial exposure, vaccine regime and dose. Objective safety measures (local reaction size and body temperature) were evaluated for correlations with adaptive antigen-specific immune responses. Results: All subjects in the combined mid-dose group developed a local reaction, of which 92% were mild, 8% were moderate and no reactions were severe. Around 90% of subjects in each group reported at least one systemic adverse event, most commonly headache, myalgia, malaise, feeling feverish, fatigue and arthralgia. Of all systemic adverse events in the combined mid-dose group, 96% were mild, 3% were moderate and 1% were severe (but none of these were judged to be vaccine-related). Pre-vaccination mycobacterial exposure did not affect the adverse event profile. The size of local reaction and frequency of systemic adverse events increased with MVA85A vaccine dose. There were no documented fevers in the low-dose group, whilst 3% of subjects in the combined mid-dose group and 21% in the high-dose group had documented fevers. Peak local reactions were larger after a second poxvirus vaccination, but other local and systemic adverse events were comparable to a single MVA85A vaccination. No severe systemic AEs or serious adverse events in any group were judged to be vaccine-related. Local AEs compared favourably to BCG vaccine-induced local AE and systemic AEs after MVA85A vaccination were comparable to those after the live viral Yellow Fever vaccine in similar populations. There were no correlations found between local reaction size or body temperature and adaptive immune responses (measured by ex vivo interferon gamma Enzyme Linked Immunospot). Conclusions: The candidate TB vaccine, MVA85A has been safely administered to over 100 healthy adults in the UK. Intradermal vaccination with MVA85A induced a transient, superficial reaction local to the injection site and mild short-lived viral symptoms. The local and systemic AE profile of MVA85A vaccination was comparable to published data of other intradermal vaccines and live viral vaccines respectively. Local reaction sizes and body temperature measurements did not correlate with the adaptive cellular immune response to MVA85A. [Copyright &y& Elsevier]

Summary: Efficient pre- and post-harvest services are essential if small farms in high potential areas are to intensify production, contribute to economic growth, and reduce poverty. They also matter if small farms in marginal areas are to manage their natural resource base, in the face of growing population pressure and climate change. Difficulties that smallholders face in accessing services are reviewed, showing how incentives for commercial delivery of services to smallholders differ between staple food, traditional cash crop, and high value product supply chains. The major challenge in service delivery to smallholders in much of Africa concerns coordination of service development and delivery. Different forms of intermediary institution for achieving such coordination are examined. [ABSTRACT FROM AUTHOR]

This article analyses the performance of cotton sectors across East, Southern, and West Africa, paying particular attention to the wide diversity of institutional arrangements that they now exhibit. It finds strong support for earlier contentions regarding trade-offs between competition and coordination, and between the roles of public and private sectors. New insights provide concrete and context-specific guidance to policy-makers and stakeholders regarding the key challenges they will face and the risks they will need to manage as they work to improve productivity and ensure an equitable division of benefits within cotton sectors. [ABSTRACT FROM AUTHOR]

This paper addresses issues relevant to a critical problem in economic development: how to get rapid pro-poor economic growth in poor rural areas in Africa and South Asia where most of the world's dollar a day poor live. It examines constraints to the development of coordinated exchange systems in poor rural areas, focusing on the core problem of thin markets and low density of economic activity in these areas. Transaction cost and risk analysis is integrated into a conventional neoclassical production economics framework to describe the existence of low level equilibrium traps in transactions and supply chains and to generate important insights for development policy. [ABSTRACT FROM AUTHOR]

Abstract: Although its arguments may have more general applicability, this paper discusses the desirability and options for the stabilisation of staple food prices principally in Eastern and Southern Africa. It addresses three broad questions: (i) why is stabilisation of food (grain) prices desirable? (ii) what is technically feasible? and (iii) can the governance and trade issues thrown up by suggested mechanisms be solved? It considers a number of options for price stabilisation, assessing the strengths and weaknesses of each and suggesting situations in which each may be appropriate. [Copyright &y& Elsevier]

In sub-Saharan Africa, there is fairly broad agreement that increased investment in key public goods such as roads and communications infrastructure, agricultural research and water control will be required if revitalised agricultural development is to take place. However, it has proved more difficult to reach agreement on what needs to be done to improve the performance of agricultural markets. In this article we set out an agenda for investment and policy reform in this area, providing a brief theoretical examination of the co-ordination problems involved before examining in turn demand and supply constraints affecting smallholder farmers, and policies for price stabilisation and the co-ordination of support services. We also argue that increased attention needs to be paid to governance issues. [ABSTRACT FROM AUTHOR]

Agricultural policy in Africa in the last 50 years can be broadly but usefully divided into two phases, emphasising first state-led and then market-led development. Neither has lived up to the promises made on its behalf, but policy debates have tended to set these two approaches off against each other. The weaknesses of this polarised debate are increasingly recognised, with the need for the state and market, and other players, to play separate but complementary roles. The authors argue that this complementarity is very important, but the distinction between state and market roles in development cannot be clear cut. Instead they propose an integrated suite of eclectic measures involving different stakeholders within a robust policy paradigm of "developmental coordination". [ABSTRACT FROM AUTHOR]

Private operators now dominate input supply, crop buying and ginning activities in many African cotton sectors. Varying levels of competition are observed, but greater levels of competition are not necessarily associated with better system performance. This paper explores this phenomenon, drawing on the liberalization experience of Ghana, Mozambique, Tanzania, Uganda, Zambia and Zimbabwe. While the capacity of the state to support markets remains weak, there may be tradeoffs between the level of competition and the degree of coordination achieved between players within a sector. Different sectoral structures are observed, with a different role for the state appropriate for each. [Copyright &y& Elsevier]