Vector-borne disease and climate change adaptation in African dryland social-ecological systems

Abstract

Background: Drylands, which are among the biosphere's most naturally limiting and environmentally variable ecosystems, constitute three-quarters of the African continent. As a result, environmental sustainability and human development along with vector-borne disease (VBD) control historically have been especially challenging in Africa, particularly in the sub-Saharan and Sahelian drylands. Here, the VBD burden, food insecurity, environmental degradation, and social vulnerability are particularly severe. Changing climate can exacerbate the legion of environmental health threats in Africa, the social dimensions of which are now part of the international development agenda. Accordingly, the need to better understand the dynamics and complex coupling of populations and environments as exemplified by drylands is increasingly recognized as critical to the design of more sustainable interventions.

Main body: This scoping review examines the challenge of vector-borne disease control in drylands with a focus on Africa, and the dramatic, ongoing environmental and social changes taking place. Dryland societies persisted and even flourished in the past despite changing climates, extreme and unpredictable weather, and marginal conditions for agriculture. Yet intrusive forces largely out of the control of traditional dryland societies, along with the negative impacts of globalization, have contributed to the erosion of dryland's cultural and natural resources. This has led to the loss of resilience underlying the adaptive capacity formerly widely exhibited among dryland societies. A growing body of evidence from studies of environmental and natural resource management demonstrates how, in light of dryland system's inherent complexity, these factors and top-down interventions can impede sustainable development and vector-borne disease control. Strengthening adaptive capacity through community-based, participatory methods that build on local knowledge and are tailored to local ecological conditions, hold the best promise of reversing current trends.

Conclusions: A significant opportunity exists to simultaneously address the increasing threat of vector-borne diseases and climate change through methods aimed at strengthening adaptive capacity. The integrative framework and methods based on social-ecological systems and resilience theory offers a novel set of tools that allow multiple threats and sources of vulnerability to be addressed in combination. Integration of recent advances in vector borne disease ecology and wider deployment of these tools could help reverse the negative social and environmental trends currently seen in African drylands.

Keywords: Adaptive vector borne disease management; Biodiversity; Climate change adaptation; Complexity; Integrated vector management; Resilience; Social-ecological system; Traditional knowledge; Vector-borne diseases.

Fig. 1

Map of Africa delineating drylands. This shows the geographic distributions of each of the four dryland types: hyper-arid, arid, semi-arid, and dry sub-humid. Each of these zones exhibits the characteristics inherent to drylands described in the text, including naturally greater climate variability than other biomes, However, Hyper-arid and Arid zones both naturally exhibit more and increasingly extreme climate and environmental conditions, including climate variability, which are expected to increase in the coming decades [2]

Fig. 2

The adaptive cycle showing how changes in social-ecological systems characteristically exhibit two phases. Following collapse, a system can repeat the cycle (the white path) or transform into another system of different structure and function (the black path). A resilient system—i.e., one less vulnerable to unexpected shifts or collapses with undesirable or even catastrophic consequence for human populations—may successfully navigate itself through each of the phases and into new regime that satisfies societal goals. That is, it need not return via the α → r transition as before a crisis, thus repeat the cycle. In general, however, successful navigation (an indication of resilience) suggests the capacity to recognize barriers, critical thresholds and principles associated with this front loop that can trap a system—resulting in a pathology. System features allowing escape from these traps have been provisionally described [78]—representing adaptive management

Fig. 3

Adaptive management of Vector-borne disease (VBD) risk in a pastoral grazing system. The figure shows the linkages between social and ecological aspects as uncovered by dryland researchers, with VBD transmission added by the work reported in the present study. The economic/livelihood benefits of ecosystem functions can be extended to include the mitigation of VBD transmission associated with landscape function. Similarly, the local knowledge of Human-Environment (H-E) interactions include how livestock management decisions in consideration of external drivers effect landscape function associated with VBD transmission. (Modified from [75], Fig. 8.7)