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

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.

Thinking beyond Opisthorchis viverrini for risk of cholangiocarcinoma in the lower Mekong region:a systematic review and meta-analysis

Background:Cholangiocarcinoma(CCA)is a fatal bile duct cancer associated with infection by the liver fluke,Opisthorchis viverrini,in the lower Mekong region.Numerous public health interventions have focused on reducing exposure to O.viverrini,but incidence of CCA in the region remains high.While this may indicate the inefficacy of public health interventions due to complex social and cultural factors,it may further indicate other risk factors or interactions with the parasite are important in pathogenesis of CCA.This systematic review aims to provide a comprehensive analysis of described risk factors for CCA in addition to O.viverrini to guide future integrative interventions.Main body:We searched five international and seven Thai research databases to identify studies relevant to risk factors for CCA in the lower Mekong region.Selected studies were assessed for risk of bias and quality in terms of study design,population,CCA diagnostic methods,and statistical methods.The final 18 included studies reported numerous risk factors which were grouped into behaviors,socioeconomics,diet,genetics,gender,immune response,other infections,and treatment for O.viverrini.Seventeen risk factors were reported by two or more studies and were assessed with random effects models during meta-analysis.This meta-analysis indicates that the combination of alcohol and smoking(OR=11.1,95%CI:5.63-21.92,P<0.0001)is most significantly associated with increased risk for CCA and is an even greater risk factor than O.viverrini exposure.This analysis also suggests that family history of cancer,consumption of raw cyprinoid fish,consumption of high nitrate foods,and praziquantel treatment are associated with significantly increased risk.These risk factors may have complex relationships with the host,parasite,or pathogenesis of CCA,and many of these risk factors were found to interact with each other in one or more studies.Conclusions:Our findings suggest that a complex variety of risk factors in addition to O.viverrini infection should be addressed in future public health interventions to reduce CCA in affected regions.In particular,smoking and alcohol use,dietary patterns,and socioeconomic factors should be considered when developing intervention programs to reduce CCA.

Fish sharing as a risk factor for Opisthorchis viverrini infection:evidence from two villages in north-eastern Thailand

Background:Foodborne trematodiasis(FBT)is a significant global health problem,with the liver flukes Opisthorchis viverrini,O.felineus,and Clonorchis sinensis contributing to half of the global burden of FBT.North-eastern Thailand where O.viverrini is endemic and un-cooked fish dishes remain an integral part of the food culture has the highest reported incidence of opisthorchiasis,including associated cholangiocarcinoma.Both food sharing and eating practices are potentially important factors in FTB,suggesting an important role for the social ecology of disease transmission in these rural communities.Methods:Two rural Thai-Lao villages that were part of a 12-village project in Northeastern Thailand were selected for detailed investigation of O.viverrini infection risk associated with sharing of raw fish dishes among households.The project included screening individuals for infection and cholangiocarcinoma,a household questionnaire,and offering treatment options for positive individuals.Social network mapping was used to construct raw fish dish-sharing networks and create a proxy variable capturing variability in the degree of food sharing(DFS),measured as the number of different households with which each household shared fish dishes.Measures of associations between DFS,O.viverrini infection,the frequency of raw fish consumption,and the number of raw fish dishes consumed were generated using binary logistic regression,proportional odds ordinal logistic regression,and Poisson regression.Results:The results showed that the probability that a household has members infected with O.viverrini increased by~7%(P<0.01)for each additional household included in its network.Moreover,the frequency and number of types of raw fish dishes consumed increased significantly as the DFS increased.Of the two villages,that with the highest infection prevalence(48%versus 34.6%)had significantly higher social connectivity overall(P<0.001).Conclusions:Our findings suggest that the social ecology of human settlements may be key to understanding the transmission dynamics of some FBT.In the case of O.viverrini in Thai-Lao communities,for which food sharing is a traditional practice supporting social cohesion,food sharing network mapping should be incorporated into community-based interventions.These should encourage fish dish preparation methods that minimize infection risk by targeting households with high DFS values.

Fostering social innovation and building adaptive capacity for dengue control in Cambodia: a case study

Background:The social-ecological systems theory,with its unique conception of resilience(social-ecological systems&resilience,SESR),provides an operational framework that currently best meets the need for integration and adaptive governance as encouraged by the Sustainable Development Goals.SESR accounts for the complex dynamics of social-ecological systems and operationalizes transdisciplinarity by focusing on community engagement,value co-creation,decentralized leadership and social innovation.Targeting Social Innovation(SI)in the context of implementation research for vector-borne diseases(VBD)control offers a low-cost strategy to contribute to lasting and contextualized community engagement in disease control and health development in low and middle income countries of the global south.In this article we describe the processes of community engagement and transdisciplinary collaboration underpinning community-based dengue management in rural primary schools and households in two districts in Cambodia.Methods:Multiple student-led and community-based interventions have been implemented focusing on empowering education,communication for behavioral change and participatory epidemiology mapping in order to engage Cambodian communities in dengue control.We describe in particular the significance of the participatory processes that have contributed to the design of SI products that emerged following iterative consultations with community stakeholders to address the dengue problem.Results:The SI products that emerged following our interaction with community members are 1)adult mosquito traps made locally from solid waste collections,2)revised dengue curriculum with hands-on activities for transformative learning,3)guppy distribution systems led by community members,4)co-design of dengue prevention communication material by students and community members,5)community mapping.Conclusions:The initiative described in this article put in motion processes of community engagement towards creating ownership of dengue control interventions tools by community stakeholders,including school children.While the project is ongoing,the project's interventions so far implemented have contributed to the emergence of culturally relevant SI products and provided initial clues regarding 1)the conditions allowing SI to emerge,2)specific mechanisms by which it happens and 3)how external parties can facilitate SI emergence.Overall there seems to be a strong argument to be made in supporting SI as a desirable outcome of project implementation towards building adaptive capacity and resilience and to use the protocol supporting this project implementation as an operational guiding document for other VBD adaptive management in the region.