The SSPHC engages in a strong research agenda consistent with the multidisciplinary approach of spatial science.
Featured Research Areas and Initiatives
Spatial Patterns of Malaria Transmission in Southern Africa
SSPHC faculty Dr. Frank Curriero and Timothy Shields direct the Environmental Surveillance Core (ESC) of the Johns Hopkins Malaria Research Institute (JHMRI) and the Johns Hopkins NIH funded International Center for Excellence in Malaria Research (ICEMR). ICEMR research, which aligns with JHMRI research, focuses on the epidemiology, vector biology and genetic diversity of malaria parasites in three endemic areas of Southern Africa with different levels of malaria transmission and stages of control.
Objectives of the Environmental Surveillance Core of the ICEMR include characterization of the social and physical environments in regions supporting ICEMR research projects. This has included developing mapped layers of climate variables, road networks, hydrology, topographical characteristics, and the use of satellite imagery for complete household location census. The ESC also includes a dedicated component in the research and application of spatial statistical methods, leading to publications involving the creation of malaria risk maps, cluster detection for identifying malaria hotspots, models to identify determinants of malaria both at the individual and environmental levels, and methods for analyzing and mapping mosquito vectors.
Dynamics and Human Health Risks of Vibrio parahaemolyticus Bacteria in Estuarine Environments
Non-cholera Vibrio species are a frequent cause of seafood-associated infections leading to an estimated 80,000 illnesses, 500 hospitalizations and 100 deaths annually in the United States. The NIH recently funded our proposal to characterize the spatial-temporal dynamics and human health risks of Vibrio parahaemolyticus Bacteria. Dr. Curriero and SPPHC Trainee Ben Davis will lead the research to assess human health risks from this emerging pathogen in two large and economically significant estuarine environments, the Chesapeake Bay and Puget Sound. Research and analysis will focus on advancing spatial and spatial-temporal statistical methods to better quantify the uncertainty of spatial predictions for these bacteria in estuarine environments. Results will be used to support the development of region-specific quantitative microbial risk assessments (QMRAs) for vibriosis, extending the Food and Drug Administration’s (FDA’s) current national risk assessment model.
Air Pollution Exposure and Health
In the United States and around the world, millions of people are exposed to dirty air, much of which is generated by human activity. Estimating the health effects of both indoor and outdoor air pollution is an important problem in public health problem that significantly effects millions of people around the world every year. Dr. Roger Peng, a leading researcher in this field, has developed statistical methods for estimating the health effects of both indoor and outdoor air pollution exposure. Because air pollution effects are relatively small (but the exposed populations are very large), state-of-the-art statistical methods are needed to capture these effects in the presence of much stronger signals, including the use of spatial-temporal modeling, Bayesian hierarchical models, and causal inference methods.
Environmentally-based Disease Early Warning Systems
Vector-borne and waterborne diseases are sensitive to variability in environmental conditions, but reliable, timely data on these conditions can be difficult to obtain. SSPHC faculty work with advanced Earth system models and data assimilation systems to provide best-available, spatially and temporally complete monitoring and forecasts of variables known to predict the distribution of vectors or pathogens. Current projects include the use of land data assimilation systems to study and monitor malaria risk in the Amazon basin, the development of satellite-derived salinity estimates that are now used to monitor Vibrio risk in Chesapeake Bay, and high resolution seasonal forecasts of heat and moisture conditions to predict human and agricultural pests in East Africa and South Asia.
Heat Exposure in Urban Environments
Extreme heat is the deadliest form of climate hazard in the United States today. The risk may be particularly high in cities, which can be several degrees warmer than the surrounding environment due to the urban heat island phenomenon. But there is relatively little information available about fine scale variability in the urban heat island, and in particular how the setting, layout, and architecture of certain neighborhoods might make them particularly prone to elevated temperatures. SSPHC faculty work with neighborhood groups and city governments to map fine scale variability in the urban heat island and to identify interventions through rapid heat wave response and, on longer timescales, improved urban design.
Methods and Procedures for Utilizing Advancing Spatial Data Technologies
Remotely sensed and satellite imagery, GPS tracking devices, ecological momentary assessments (EMA), crowd sourcing; technologies to obtain, collect and create spatial information continues to advance. Developing and integrating spatial methods for studies utilizing these advancing technologies is an active area of research. A team led by Faculty Tim Shields have developed satellite-based methods for household level location census, a methodological approach that provides the sampling basis for JHMRI and ICEMR research studies. Procedures were also established to evaluate the temporal validity (shelf-life) of satellite images when used for human population studies. Current SSPHC research in this area incorporates spatial methods for GPS tracked/mobility data and also for characterizing environments in space and time for studies utilizing EMA.
Translational Research across Multiple Applications
SSPHC faculty continue to engage in translational research, developing and applying tools of spatial analysis supporting research across multiple public health applications. A brief description of some previous and ongoing work is highlighted below:
Clustering, cluster detection and spatial variation in risk of outcomes related to chronic diseases, infectious diseases and injury.
Spatial attributes operating at the intersection of health and behavior, for example risky behaviors and sexual health, safety/crime, and mobility.
- Characterizing environments and their effects on health such as with the built environment, food environment, demographic, social and behavior environments, agriculture environment as well as exposure assessments for drug, crime, alcohol, air and water environments.
New collaborations and extending our current ones are always welcome.