Pilot Grants Funded

“Effects of extreme climate events on environmental reservoirs and dispersion of Legionella”

Principal Investigator

Daniel Weinberger
Assistant Professor
Department of Epidemiology of Microbial Diseases Yale School of Public Health 
daniel.weinberger@yale.edu

Flooding in CT

Abstract

Legionella pneumophila is a poorly understood but increasingly common cause of community acquired pneumonia in the US. The bacterium has been studied separately in the hydrological and epidemiological sciences, but we propose a unique collaboration between these fields to further our understanding of Legionella. More specifically, we will clarify the role of climate change—particularly warming temperatures and high intensity storm events—on the spread of Legionella and resulting clustering of non-outbreak “sporadic” disease. Expertise will come from an interdisciplinary team of researchers from epidemiology and biostatistics at Yale School of Public Health, biogeochemists at Yale School of Forestry, and public health practitioners from the Connecticut Emerging Infections Program/Department of Public Health. Our study would use a mix of quantitative analyses of existing public health data and testing of environmental water and aerosol samples to evaluate hypotheses about the observed long-terms trends and spatial variations in the incidence of legionellosis. Outcomes will include identification of drivers for environmental Legionella “hot spots”, estimation of the time Legionella remains suspended in water and aerosols after intense storm events, and elucidation of threshold climatic events that significantly increase rates of disease. These data and models will then be used to generate forecasts of legionellosis under different climate change scenarios. The proposed studies will provide important information regarding the climatic drivers of an emerging infection of public health significance.

Consequences of climate change for risk of enteric infections: investigating links between hydrology and water-borne disease

Principal Investigators:

Virginia Pitzer
Assistant Professor
Department of Epidemiology of Microbial Diseases Yale School of Public Health 
virginia.pitzer@yale.edu

Daniel Weinberger
Assistant Professor
Department of Epidemiology of Microbial Diseases Yale School of Public Health
daniel.weinberger@yale.edu

William Boos
Associate Professor
Department of Geology and Geophysics Yale University 
william.boos@yale.edu

Flooding in Katmandu

Abstract

To predict the impact of climate change on future infectious disease incidence, it is essential to robustly quantify the climate-disease relationship. Appropriately attributing changes in disease incidence to climate change often requires building a mechanistic understanding from relatively short time-series of climatic variables and disease incidence—a process that relies on harnessing spatial variation and/or biological knowledge. We will focus on quantifying associations between water-borne enteric diseases and hydrologically-relevant climatic variables. Using a meta-regression approach, we will reevaluate studies that have examined the effect of climate on enteric diseases across a wide range of geographic locations. We will seek to identify the sources of heterogeneity and relevant climatic variables that lead to more consistent findings than have been previously reported. We will then focus on one particular climate-disease system—precipitation and typhoid fever in Kathmandu, Nepal—and employ both statistical and mathematical models to quantify the relationship between various hydrological metrics, bacterial contamination of water supplies, and the incidence of typhoid fever cases while controlling for epidemiological and immune-driven feedbacks over a 14-year time period. These analyses will provide the foundation and methodological developments necessary to inform future studies that link predictive models of enteric disease incidence to climate change projections.