All Hands on Deck: Transdisciplinary Approaches to Emerging Infectious Disease

The increasing burden of emerging infectious diseases worldwide confronts us with numerous challenges, including the imperative to design research and responses that are commensurate to understanding the complex social and ecological contexts in which infectious diseases occur. A diverse group of scientists met in Hawaii in March 2005 to discuss the linked social and ecological contexts in which infectious diseases emerge. A subset of the meeting was a group that focused on “transdisciplinary approaches” to integrating knowledge across and beyond academic disciplines in order to improve prevention and control of emerging infections. This article is based on the discussions of that group. Here, we outline the epidemiological legacy that has dominated infectious disease research and control up until now, and introduce the role of new, transdisciplinary and systems-based approaches to emerging infectious diseases. We describe four cases of transboundary health issues and use them to discuss the potential benefits, as well as the inherent difficulties, in understanding the social–ecological contexts in which infectious diseases occur and of using transdisciplinary approaches to deal with them. The views expressed here by Marian McDonald and Josh Rosenthal are those of the authors and do not represent official views or policies of the U.S. Centers for Disease Control and Prevention or the National Institutes of Health.     

Emerging and Reemerging Infectious Diseases: Biocomplexity as an Interdisciplinary Paradigm

Understanding factors responsible for reemergence of diseases believed to have been controlled and outbreaks of previously unknown infectious diseases is one of the most difficult scientific problems facing society today. Significant knowledge gaps exist for even the most studied emerging infectious diseases. Coupled with failures in the response to the resurgence of infectious diseases, this lack of information is embedded in a simplistic view of pathogens and disconnected from a social and ecological context, and assumes a linear response of pathogens to environmental change. In fact, the natural reservoirs and transmission rates of most emerging infectious diseases primarily are affected by environmental factors, such as seasonality or meteorological events, typically producing nonlinear responses that are inherently unpredictable. A more realistic view of emerging infectious diseases requires a holistic perspective that incorporates social as well as physical, chemical, and biological dimensions of our planet’s systems. The notion of biocomplexity captures this depth and richness, and most importantly, the interactions of human and natural systems. This article provides a brief review and a synthesis of interdisciplinary approaches and insights employing the biocomplexity paradigm and offers a social–ecological approach for addressing and garnering an improved understanding of emerging infectious diseases. Drawing on findings from studies of cholera and other examples of emerging waterborne, zoonotic, and vectorborne diseases, a “blueprint” for the proposed interdisciplinary research framework is offered which integrates biological processes from the molecular level to that of communities and regional systems, incorporating public health infrastructure and climate aspects.     

Emerging zoonotic diseases originating in mammals: a systematic review of effects of anthropogenic land-use change

1. Zoonotic pathogens and parasites that are transmitted from vertebrates to humans are a major public health risk with high associated global economic costs. The spread of these pathogens and risk of transmission accelerate with recent anthropogenic land-use changes (LUC) such as deforestation, urbanisation, and agricultural intensification, factors that are expected to increase in the future due to human population expansion and increasing demand for resources.
2. We systematically review the literature on anthropogenic LUC and zoonotic diseases, highlighting the most prominent mammalian reservoirs and pathogens, and identifying avenues for future research.
3. The majority of studies were global reviews that did not focus on specific taxa. South America and Asia were the most-studied regions, while the most-studied LUC was urbanisation. Livestock were studied more within the context of agricultural intensification, carnivores with urbanisation and helminths, bats with deforestation and viruses, and primates with habitat fragmentation and protozoa.
4. Research into specific animal reservoirs has improved our understanding of how the spread of zoonotic diseases is affected by LUC. The behaviour of hosts can be altered when their habitats are changed, impacting the pathogens they carry and the probability of disease spreading to humans. Understanding this has enabled the identification of factors that alter the risk of emergence (such as virulence, pathogen diversity, and ease of transmission). Yet, many pathogens and impacts of LUC other than urbanisation have been understudied.
5. Predicting how zoonotic diseases emerge and spread in response to anthropogenic LUC requires more empirical and data synthesis studies that link host ecology and responses with pathogen ecology and disease spread. The link between anthropogenic impacts on the natural environment and the recent COVID-19 pandemic highlights the urgent need to understand how anthropogenic LUC affects the risk of spillover to humans and spread of zoonotic diseases originating in mammals.

     

Fishes as indicators of environmental and ecological changes within estuaries: a review of progress and some suggestions for the future

Estuarine habitats, and the fish assemblages associated with them, are potentially impacted upon by many anthropogenic influences which can have a direct influence on the food resources, distribution, diversity, breeding, abundance, growth, survival and behaviour of both resident and migrant fish species. The direct and indirect coupling between ichthyofaunal communities and human impacts on estuaries reinforces the choice of this taxonomic group as a biological indicator that can assist in the formulation of environmental and ecological quality objectives, and in the setting of environmental and ecological quality standards for these systems. This review examines the rationale and value of selecting fishes as bio-indicators of human induced changes within estuaries, using examples from both the northern and southern hemispheres. The monitoring of estuarine 'health' using fish studies at the individual and community level is discussed, with an emphasis on the potential use of estuarine fishes and their monitoring and surveillance in national and international management programmes. In illustrating the above concept, examples are presented of the way in which fishes are threatened by anthropogenic impacts and of the way in which teleosts can contribute to a monitoring of estuarine ecosystem health.     

Approaches to assessing and managing cumulative ecosystem change,with the Bay of Quinte as a case study: an essay

Rising concern for the future of humans and the earth's ecosystems provides the backdrop for an essay on approaches to assessing and managing ecosystem health. A review and critique of two rival metaphors of human health, illness and wellness, provide the staring point for evaluation of parallel approaches to the assessment and management of ecosystems. The limitations of the metaphors are noted for humans and ecosystems. The impact assessment and ecosystem approach concepts of ecosystem assessment and management are contrasted. As a case history, the nature and pace of change in the Bay of Quinte ecosystem are reviewed, spanning from colonization by the Empire Loyalists at the end of the 18th century through the current development of a remedial action plan for the ecosystem. The review includes the long-term scientific study of the Bay's response to point-source phosphorus control (Project Quinte) and the recent efforts to develop and implement a coordinated clean-up program (Remedial Action Plan). From the lessons of the Quinte experience, a framework is derived, combining the illness and wellness approaches to health. The framework deals with five topics: uncertainty and the precautionary principle; an ecosystem health scale; indicators of ecosystem health; maximum allowable change; and, regulation and planning. Uncertainty should not be used to justify inaction. A precautionary principle assumes that impacts will occur and places the burden of proof on the proponents of ecosystem disturbance. An ecosystem health scale is defined using current, original, and potential conditions. Restoration to the original condition is unlikely but provides a justifiable direction for actions to establish sustainability. Indicators of ecosystem health with sustainable ranges are preferred over end-points and thresholds. The concept of maximum allowable change is promoted with a tentative suggestion that a fifty percent rule might be used. Finally, an argument for the combined use of regulation and planning. Regulatory approaches tend to perpetuate confrontation. Planning can be used to lengthen the time-horizon from quarterly reports to generations and identify self-regulating codes of behaviour. The framework is briefly discussed and placed in a broader context linking humans and ecosystem, illness and wellness.Based on the text of a talk presented at the Cumulative Impact Assessment Workshop held in Toronto, Ontario, December 1992, and sponsored by the North Central Division of the American Fisheries Society.