The management of water resources to reduce the public health burden of environmentally-transmitted diseases is considered an historical success story resulting from collaborations between public health personnel, biologists and hydrological engineers. The elimination of cholera through engineering that separates sewage from drinking water is an example, especially in the more developed areas. The Tennessee Valley Authority reduced malaria during the 1930s by combining insecticides with the reduction of mosquito breeding sites by varying water levels. In spite of these successes, the global human health burden due to diseases transmitted by mosquitoes remains high and in some cases is increasing. The World Health Organization estimates that about 2.5 billion people are now at risk of contact with the mosquito-borne dengue virus (WHO 2012). In 1999, West Nile virus expanded its range significantly, when it was first seen in North America (Lanciotti et al. 1999). Another mosquito-borne virus - Chikungunya, had a surprise resurgence in the Indian Ocean region in 2005, spreading throughout the region and north into Italy (Simon et al. 2008). In all cases, when mosquitoes carry pathogens, their emergence and persistence are intimately tied to aquatic systems. Mosquitoes require standing water for their larval development and they need to maintain moisture as adults. The reduction of these important health threats depends on the control of mosquito vectors and the reductions that can be achieved with lower doses of insecticides has a strong environmental benefit. Our ability to link water management decisions and practices to mosquito production is limited by the lack of interaction among hydrologists, public health officials, disease modelers and biologists. We propose an interdisciplinary approach to gain a better understanding of the way in which hydrological modeling and water management methods can affect the distribution of mosquito vectors and thus reduce prevalence of infectious diseases that are vectored by mosquitoes. Our emphasis is on realistic, systems-based analyses to improve public health interventions and policy. Hence, a truly interdisciplinary approach is needed to address this grand challenge of reducing future disease burdens in human-altered aquatic landscapes under global climate change.
Our training model is aimed at providing the next generation of scientists, mathematicians and engineers with the skills and connections they will need to take an interdisciplinary approach to predicting and managing the prevalence of infectious disease in both wildlife and human populations through the reduction of mosquito populations that pose a risk of human illness. To do so, we leverage our existing experience with a campus-wide graduate program (Program in Ecology, Evolution and Conservation Biology) and an NSF IGERT (Vertically Integrative Training with Genomics), a seed grant in Civil and Environmental Engineering (Ecohydrologic Acclimation Under Climate Change: Exploring Opportunities for Malaria Control) as well as our experience with an interdisciplinary undergraduate training program (BioMath), with the additional opportunities provided by a Focal Point grant. The centerpiece is the development of a new, yearlong multidisciplinary seminar course, designed and implemented by the core faculty, required of the core participants and open to the entire campus. The course “Interdisciplinary training in hydrology and infectious diseases” will consist of 7 training modules (Table 1). Students will also be assigned to interdisciplinary teams for a year-long group project, on which they will present twice, once at the end of the fall semester and again at the end of the year in a campus – wide workshop. Group projects will be student-driven and related to the main research themes described below. Although all named graduate students have interest in at least one discipline-specific area, all students will work on an aspect of the project that is outside of their core thesis work, thereby exposing them to a new area and facilitating the development of a novel skillset. In addition to the oral presentations given by the students, we expect that our Focal Point group will produce at least one collaborative review paper for publication over the course of the year. The topics of the course will be organized around a set of cross-cutting themes and a set of three disease systems, described below.Sub-topic 1: Elements of complex systems and models of mosquito-borne diseases
The strategy for our approach is at the interface of ecology, evolution, climatology, hydrology, mathematics and epidemiology with support from spatial, temporal and population models and specialized expertise in specific disease systems and their local natural history and geography. Due to this complex network of interactions, making specific predictions regarding the effects of water management on human health, particularly in developing nations, remains an enormous challenge. We believe that different disciplinary approaches to modeling vary conceptually, with varying vocabularies, methods and desired outcomes, resulting in barriers to true interdisciplinary efforts. We will consider modeling efforts that both span disciplines and that exemplify approaches from a particular discipline, including considerations of: 1) differences between statistical and mathematical models; 2) uses of simulation models; 3) hydrological and climatological modeling; 4) biological population models; 5) epidemiological approaches, and 6) spatio-temporal issues that span these. The complex network of hydro-climatological, ecological, socio-economic, entomological, and parasitological interactions may be altered by the changes in temperature and to the water cycle that are predicted in coming decades, but there is little consensus on what will be the net outcome of these interacting factors on mosquito vectors and how to approach their analysis. Faculty, students, and guest speakers will learn about and discuss these differences and connections.Sub-topic 2: Water management practices and mosquito-borne diseases
Many water management practices have considerable potential to influence disease spread. Irrigated agriculture is critical to food security, for example, but it has also been associated with increased risk of disease (Hunter et al. 1993). Currently, more than 65% of the world’s freshwater resources are used for irrigated agriculture (Postel 1996). Further, urban water management is a widespread challenge faced by hydrological engineers in urban ecosystems, and storm water management structures are related to the breeding habitat of vector mosquitoes. The vectors of WNV thrive in polluted stagnant water in urban catch basins and in conditions where combined sewer systems result in overflows (Rey et al. 2006, Vazquez-Prokopec et al. 2010, Gardner et al. 2012, 2013). Increases in nutrient inputs (eutrophication) or pesticides to aquatic systems can increase the prevalence of diseases, suggesting that the composition of the aquatic environments themselves can alter disease dynamics (Johnson et al. 2007, Rohr et al. 2008, Muturi et al. 2011). Vectors for dengue virus are often found in water containers, and these containers are even more important sources during times of drought or when fresh water is in short supply (Lifson 1996). We will consider the various aspects of water management from diverse perspectives and the life cycle of mosquito vectors to better link mosquito-borne diseases prevalence to water management strategies. This will include how climate-linked hydrological models help to explore how climate change affects vegetation function and associated hydrology, thereby affecting water residence times in the topographic depressions and the effect on the mosquito life cycle.Sub-topic 3: West Nile virus, malaria, dengue, and chikungunya as model systems
Among the faculty participants, we will leverage ongoing research in mosquito-borne disease systems to better exemplify the value and challenges of modeling various aspects of mosquito-borne illnesses with real data. In addition, the Focal Point activities will provide means to broaden existing international connections built around these systems. The three disease systems on which we will focus are: West Nile virus in Illinois, malaria in Kenya, and dengue and chikungunya viruses in Sri Lanka. In the Illinois West Nile virus system, urban catch basins hold runoff, creating ideal larval sites for the mosquito vector of West Nile. The effect of “green” storm water best management practices, such as street-level techniques and green infrastructures can affect mosquito habitats. Analyses will benefit from fine scale models of urban runoff from high-resolution elevation models from LIDAR, from detailed vegetation data and from novel hydrological models, to explore how the runoff from areas of varying size and composition affects the opportunities for mosquito breeding. Broader models will be considered on the relationship between temperature, rainfall and increased risk for mosquito infections and abundance given different climate-change scenarios. This system will provide a local ecosystem for field work examples and involvement with local public health personnel and engineers. Malaria in Kenya work will focus on how irrigation affects the dynamics of the mosquitoes that transmit malaria. Irrigation may be associated with higher densities of malaria vectors with shorter adult lifespans that cannot support the malarial extrinsic incubation period (Manoukis et al. 2006). The biting nuisance caused by the large number of mosquitoes in irrigated areas may also compel people to adopt vector control measures (e.g. use of bed nets) leading to reduced human-vector contact (Mutero et al. 2004b). Agricultural fertilizers may be associated with increased larval densities (Muturi et al. 2007) while exposure of mosquito larvae to sublethal concentrations of pesticides can enhance vector competence for pathogens (Muturi et al. 2011). Dr. Muturi, a faculty participant has collaborators from the Kenya Medical Research Institute, at the Center for Geographic Medicine, and at the International Center for Insect Physiology and Ecology. Dengue and Chikungunya viruses and water issues in Sri Lanka and India is the third system of interest. In Sri Lanka, the number of dengue cases has increased, and major dengue outbreak in 2004 resulted in almost 15,500 cases reported, (Kanakaratne et al. 2009). Chikungunya virus is carried by the same mosquito vectors and experienced an outbreak in 2005 - 2006 (Simon et al 2008). Faculty participant Marilyn O’Hara is serving as a consultant on geospatial modeling to the Centre for Dengue Research, University of Sri Jayewardenapura in Sri Lanka. One important goal of this activity is to use experience from WNV in Chicago as a model for understanding the eco-epidemiology of dengue infection and vectors in a tropical city. The role of the water in canals left from Sri Lanka’s Dutch era, the effect of tropical rain patterns, the role of slum housing, changes due to global climate change, and the many issues of water containers in slum areas will be unique foci in Sri Lanka relative to Illinois. Faculty participant Praveen Kumar is working with Professor Shashidhar at Indian Institute of Technology (IIT), Hyderabad (India) to develop predictive models for dengue. We anticipate that the Focal Point group will help the University of Illinois to develop deeper ties with the University of Jayewardenapura and IIT-Hyderbad around the area of urban mosquito vectors, emerging mosquito-borne illnesses and water management.