Adapting to vector-borne diseases under climate change : an evidence-informed approach

Les preuves s'accumulent sur les effets des changements climatiques. Étant donné leurs impacts sur la santé, en particulier sur les maladies à transmission vectorielle, il est nécessaire de concevoir des stratégies efficaces pour adapter les programmes de gestion de risque de ces maladies. Les changements climatiques constituent un problème complexe, impliquant de multiples parties prenantes et comportant beaucoup d’inconnues. Des approches qui prennent en compte cette complexité sont ainsi nécessaires afin de faire avancer la recherche sur l'adaptation aux changements climatique basée autant sur des données scientifiques que sur des données provenant de différents intervenants. Les approches fondées sur les données probantes sont de plus en plus recherchées dans les politiques de santé et la prise de décisions, dans le but d'améliorer la santé des populations. Ces approches sont apparues en réaction aux approches improvisées, développées suite aux crises liées aux problèmes de santé publique. Elles doivent être systématiques et transparentes, et faire appel aux meilleures preuves disponibles. L'aide à la décision multicritère délibérative constitue une de ces approches. L'objectif de cette thèse était d'étudier les principales préoccupations en matière de décisions relatives à l'adaptation au risque des maladies vectorielles influencées par les changements climatiques dans deux contextes : le Québec, où les maladies vectorielles sont présentes, mais ne constituent pas la principale préoccupation, et le Burkina Faso, où les maladies vectorielles sont au contraire très préoccupantes. Les fondements théoriques de cette étude sont basés sur la science post-normale, l'adaptation aux changements climatiques et une approche d'analyse de décision multicritère. La recherche sur l'adaptation aux changements climatiques vise à influencer les politiques cherchant à réduire les risques et les impacts associés à ces changements. Dans ce cadre et dans le contexte de l'adaptation aux maladies vectorielles, trois questions clés se posent : 1) de quelles maladies nous préoccupons-nous ? 2) qui est le plus vulnérable à ces maladies ? et 3) quelles sont les mesures recommandées pour s'adapter à ces maladies ? Cette thèse contribuera à répondre à ces trois questions dans le but de faire avancer l'adaptation face aux maladies vectorielles. Pour répondre à la première question, nous avons identifié des préoccupations d'importance pour la priorisation des maladies liées aux changements climatiques au Québec et au Burkina Faso grâce à l’utilisation d’une approche délibérative multicritère d'aide à la décision. Les résultats ont démontré que, alors que des préoccupations générales sont partagées entre ces deux régions, des préoccupations plus spécifiques aux maladies diffèrent quant à elles selon le contexte, tant sur des aspects scientifiques que sur d’autres aspects partagés par les parties prenantes. Pour répondre à la deuxième question, les connaissances actuelles et les comportements de la population québécoise quant au virus du Nil occidental ont été explorés, comme étape préliminaire pour évaluer la capacité d'adaptation au risque de maladies causées par les moustiques. Nous avons considéré que la réponse au risque perçu de maladies transmises par les moustiques constituait une forme d'adaptation. Les résultats ont montré que les connaissances globales et les niveaux d'adoption comportementale sont bons et qu’il existe au moins quatre sous-groupes différents dans la population caractérisés par différents facteurs associés à l'adoption de comportements préventifs. Enfin, pour répondre à la troisième question, une approche multicritère délibérative a été utilisée pour examiner les stratégies de gestion du virus du Nil occidental au Québec, dans le cadre théorique d’une transmission accrue, et les stratégies de gestion du paludisme au Burkina Faso, dans le cadre de la transmission actuelle. De manière analogue au modèle développé pour la priorisation des maladies, cette comparaison entre les deux régions et les contextes de maladie ont permis de confirmer l’existence de préoccupations générales partagées. Cette thèse a permis de démontrer la pertinence des approches d'aide à la décision pour explorer des stratégies de gestion efficaces basées sur l'expérience des intervenants et les meilleures preuves scientifiques disponibles.Evidence is accumulating on the ongoing effects of climate change. Given the anticipated health implications, notably vector-borne disease impacts, there is a need to design effective and tailored strategies to adapt to vector-borne disease risk. Climate change is a complex problem, involving multiple stakeholders and many unknowns. As such, approaches that can embrace this complexity are needed to inform adaptation research with evidence - both scientific and stakeholder-informed. Evidence-informed approaches are being increasingly sought in health policy and decision-making in order to improve population health. Evidence-informed approaches have arisen in reaction to ad-hoc, crisis-driven responses to health problems. They recognize the need to be systematic and transparent, and make use of the best available evidence. Deliberative multicriteria decision aid is one such approach. The objective of this thesis was to study key decision concerns of importance in adapting to vector-borne disease risk under climate change in two contexts: Quebec, where vector-borne diseases are present but not the main burden of disease, and Burkina Faso, where vector-borne diseases contribute to the primary burden of disease. The theoretical underpinnings of this study are rooted in post-normal science, climate change adaptation, and a multicriteria decision analysis approach. Climate change adaptation research is aimed at informing policies to reduce risks and impacts associated with climate change. Within this framework, and in the context of vector-borne disease adaptation, three key questions arise: 1) what diseases are we concerned about? 2) who is most vulnerable and at risk to these diseases? and 3) what are recommended measures to adapt to these diseases? This thesis contributes to these three dimensions to inform adaptation to vector-borne disease. With regards to the first question, we identified concerns of importance for disease prioritization under climate change in both Quebec and Burkina Faso using a deliberative multi-criteria decision aid approach. The results showed that general concerns are shared among these contrasting contexts while specific disease priorities differ as a result of context-informed evidence – both scientific and stakeholder-shared. With regards to the second question, current knowledge and readiness of the Quebec population relative to West Nile virus was explored as a preliminary and integral step to assessing adaptive capacity to mosquito-borne disease risk. Here, response to perceived mosquito-borne disease risk constitutes a form of adaptation. The results showed that overall knowledge and behavioural adoption levels are good though at least four different subgroups exist within the population with different factors associated with preventive behaviour adoption. Finally, with respect to the third question, a deliberative multi-criteria approach was used to examine management strategies for West Nile virus in Quebec and malaria in Burkina Faso. West Nile virus strategies under current and theoretical increased transmission were explored in Quebec, and malaria management strategies under current transmission were explored in Burkina Faso. Analogously to the model developed for disease prioritization, shared general concerns were found between the contrasting country and disease contexts lending support to the practical applications of decision-aid approaches for exploring effective management strategies informed by stakeholder experience and the best available scientific evidence

On the Gabor frame set for compactly supported continuous functions

We identify a class of continuous compactly supported functions for which the known part of the Gabor frame set can be extended. At least for functions with support on an interval of length two, the curve determining the set touches the known obstructions. Easy verifiable sufficient conditions for a function to belong to the class are derived, and it is shown that the B-splines (Formula presented.) , (Formula presented.) , and certain ???continuous and truncated??? versions of several classical functions (e.g., the Gaussian and the two-sided exponential function) belong to the class. The sufficient conditions for the frame property guarantees the existence of a dual window with a prescribed size of the support.ope

Complex coevolutionary history of symbiotic Bacteroidales bacteria of various protists in the gut of termites

<p>Abstract</p> <p>Background</p> <p>The microbial community in the gut of termites is responsible for the efficient decomposition of recalcitrant lignocellulose. Prominent features of this community are its complexity and the associations of prokaryotes with the cells of cellulolytic flagellated protists. Bacteria in the order Bacteroidales are involved in associations with a wide variety of gut protist species as either intracellular endosymbionts or surface-attached ectosymbionts. In particular, ectosymbionts exhibit distinct morphological patterns of the associations. Therefore, these Bacteroidales symbionts provide an opportunity to investigate not only the coevolutionary relationships with the host protists and their morphological evolution but also how symbiotic associations between prokaryotes and eukaryotes occur and evolve within a complex symbiotic community.</p> <p>Results</p> <p>Molecular phylogeny of 31 taxa of Bacteroidales symbionts from 17 protist genera in 10 families was examined based on 16S rRNA gene sequences. Their localization, morphology, and specificity were also examined by fluorescent in situ hybridizations. Although a monophyletic grouping of the ectosymbionts occurred in three related protist families, the symbionts of different protist genera were usually dispersed among several phylogenetic clusters unique to termite-gut bacteria. Similar morphologies of the associations occurred in multiple lineages of the symbionts. Nevertheless, the symbionts of congeneric protist species were closely related to one another, and in most cases, each host species harbored a unique Bacteroidales species. The endosymbionts were distantly related to the ectosymbionts examined so far.</p> <p>Conclusion</p> <p>The coevolutionary history of gut protists and their associated Bacteroidales symbionts is complex. We suggest multiple independent acquisitions of the Bacteroidales symbionts by different protist genera from a pool of diverse bacteria in the gut community. In this sense, the gut could serve as a reservoir of diverse bacteria for associations with the protist cells. The similar morphologies are considered a result of evolutionary convergence. Despite the complicated evolutionary history, the host-symbiont relationships are mutually specific, suggesting their cospeciations at the protist genus level with only occasional replacements.</p

Multi-Criteria Decision Analysis as an Innovative Approach to Managing Zoonoses: Results from a Study on Lyme Disease in Canada

ackground: Zoonoses are a growing international threat interacting at the human-animal-environment interface and call for transdisciplinary and multi-sectoral approaches in order to achieve effective disease management. The recent emergence of Lyme disease in Quebec, Canada is a good example of a complex health issue for which the public health sector must find protective interventions. Traditional preventive and control interventions can have important environmental, social and economic impacts and as a result, decision-making requires a systems approach capable of integrating these multiple aspects of interventions. This paper presents the results from a study of a multi-criteria decision analysis (MCDA) approach for the management of Lyme disease in Quebec, Canada. MCDA methods allow a comparison of interventions or alternatives based on multiple criteria. Methods: MCDA models were developed to assess various prevention and control decision criteria pertinent to a comprehensive management of Lyme disease: a first model was developed for surveillance interventions and a second was developed for control interventions. Multi-criteria analyses were conducted under two epidemiological scenarios: a disease emergence scenario and an epidemic scenario. Results: In general, we observed a good level of agreement between stakeholders. For the surveillance model, the three preferred interventions were: active surveillance of vectors by flagging or dragging, active surveillance of vectors by trapping of small rodents and passive surveillance of vectors of human origin. For the control interventions model, basic preventive communications, human vaccination and small scale landscaping were the three preferred interventions. Scenarios were found to only have a small effect on the group ranking of interventions in the control model. Conclusions: MCDA was used to structure key decision criteria and capture the complexity of Lyme disease management. This facilitated the identification of gaps in the scientific literature and enabled a clear identification of complementary interventions that could be used to improve the relevance and acceptability of proposed prevention and control strategy. Overall, MCDA presents itself as an interesting systematic approach for public health planning and zoonoses management with a “One Health” perspective

MetaBioME: a database to explore commercially useful enzymes in metagenomic datasets

Microbial enzymes have many known applications as biocatalysts in biotechnology, agriculture, medical and other industries. However, only a few enzymes are currently employed for such commercial applications. In this scenario, the current onslaught of metagenomic data provides a new unexplored treasure trove of genomic wealth that can not only enhance the enzyme repertoire by the discovery of novel commercially useful enzymes (CUEs) but can also reveal better functional variants for existing CUEs. We prepared a catalogue of CUEs using text mining of PubMed abstracts and other publicly available information, and manually curated the data to identify 510 CUEs. Further, in order to identify novel homologues of these CUEs, we identified potential ORFs in publicly available metagenomic datasets from 10 diverse sources. Using this strategy, we have developed a resource called MetaBioME (http://metasystems.riken.jp/metabiome/) that comprises (i) a database of CUEs and (ii) a comprehensive platform to facilitate homology-based computational identification of novel homologous CUEs from metagenomic and bacterial genomic datasets. Using MetaBioME, we have identified several novel homologues to known CUEs that can potentially serve as leads for further experimental verification

Spatially explicit multi-criteria decision analysis for managing vector-borne diseases

The complex epidemiology of vector-borne diseases creates significant challenges in the design and delivery of prevention and control strategies, especially in light of rapid social and environmental changes. Spatial models for predicting disease risk based on environmental factors such as climate and landscape have been developed for a number of important vector-borne diseases. The resulting risk maps have proven value for highlighting areas for targeting public health programs. However, these methods generally only offer technical information on the spatial distribution of disease risk itself, which may be incomplete for making decisions in a complex situation. In prioritizing surveillance and intervention strategies, decision-makers often also need to consider spatially explicit information on other important dimensions, such as the regional specificity of public acceptance, population vulnerability, resource availability, intervention effectiveness, and land use. There is a need for a unified strategy for supporting public health decision making that integrates available data for assessing spatially explicit disease risk, with other criteria, to implement effective prevention and control strategies. Multi-criteria decision analysis (MCDA) is a decision support tool that allows for the consideration of diverse quantitative and qualitative criteria using both data-driven and qualitative indicators for evaluating alternative strategies with transparency and stakeholder participation. Here we propose a MCDA-based approach to the development of geospatial models and spatially explicit decision support tools for the management of vector-borne diseases. We describe the conceptual framework that MCDA offers as well as technical considerations, approaches to implementation and expected outcomes. We conclude that MCDA is a powerful tool that offers tremendous potential for use in public health decision-making in general and vector-borne disease management in particular

A thiol-mediated active membrane transport of selenium by erythroid anion exchanger 1 protein

In this paper, we describe a thiol-mediated and energy-dependent membrane transport of selenium by erythroid anion exchanger 1 (AE1, also known as band 3 protein). The AE1 is the most abundant integral protein of red cell membranes and plays a critical role in the carbon dioxide transport system in which carbon dioxide is carried as bicarbonate in the plasma. This protein mediates the membrane transport of selenium, an essential antioxidant micronutrient, from red cells to the plasma in a manner that is distinct from the already known anion exchange mechanism. In this pathway, selenium bound to the cysteine 93 of the hemoglobin β chain (Hb-Cysβ93) is transported by the relay mechanism to the Cys317 of the amino-terminal cytoplasmic domain of the AE1 on the basis of the intrinsic interaction between the two proteins and is subsequently exported to the plasma via the Cys843 of the membrane-spanning domain. The selenium export did not occur in plain isotonic buffer solutions and required thiols, such as albumin, in the outer medium. Such a membrane transport mechanism would also participate in the export pathways of the nitric oxide vasodilator activity and other thiol-reactive substances bound to the Hb-Cysβ93 from red cells to the plasma and/or peripherals

Potential for nitrogen fixation in fungus-growing termite symbiosis

Termites host a gut microbiota of diverse and essential symbionts that enable specialization on dead plant material; an abundant, but nutritionally imbalanced food source. To supplement the severe shortage of dietary nitrogen (N), some termite species make use of diazotrophic bacteria to fix atmospheric nitrogen (N2). Fungus-growing termites (subfamily Macrotermitinae) host a fungal exosymbiont (genus Termitomyces) that provides digestive services and the main food source for the termites. This has been thought to obviate the need for N2-fixation by bacterial symbionts. Here we challenge this notion by performing acetylene reduction assays of live colony material to show that N2 fixation is present in two major genera (Macrotermes and Odontotermes) of fungus-growing termites. We compare and discuss fixation rates in relation to those obtained from other termites, and suggest avenues of research that may lead to a better understanding of N2 fixation in fungus-growing and other termites