An innovative research project that will quantify the association between climatic variables and the incidence of water-borne intestinal diseases has received the Yale Climate Change and Health Initiative’s first pilot research grant following a competitive process that included 9 letters of intent and 4 full applications.
The study will seek to develop novel approaches to identify conditions under which changes in the incidence of water-borne intestinal diseases can be attributed to climate. This, in turn, will help answer the question of why positive associations between climatic variables and disease incidence have been reported in some studies, while negative associations have been reported in others.
The Yale Climate Change and Health Initiative (CCHI) is a Yale School of Public Health program that makes use of Yale’s multidisciplinary expertise and global reach to train future leaders, provide a comprehensive educational program, and catalyze innovative research to address climate change, which has profound implications for human health and is one of the greatest public health challenges of the 21st century.
“Intestinal infections and the consequent diarrheal disease represent a leading cause of death among infants and young children in developing countries. Gaining a detailed understanding the relationship between temperature, rainfall, humidity and other climatic variables and risk of these diseases, which are often transmitted by contaminated water, is a crucial first step to projecting how climate change will affect risk in the future.” said Professor Robert Dubrow, director of CCHI.
The study’s principle investigators are Virginia Pitzer, assistant professor, Department of Epidemiology of Microbial Diseases at the School of Public Health; Daniel Weinberger, assistant professor, Department of Epidemiology of Microbial Diseases at the School of Public Health; and William Boos, associate professor, Department Geology and Geophysics.
With the $25,000 grant, the researchers will use detailed data sets that will enable them to follow the pathway from regional climatic conditions to localized contamination of different sources of drinking water to population-level incidence of typhoid fever in Kathmandu, Nepal. Then, they will examine the impact of climate while accounting for epidemiological and immune-driven feedbacks in typhoid transmission.
Gaining a detailed understanding the relationship between temperature, rainfall, humidity and other climatic variables … is a crucial first step to projecting how climate change will affect risk in the future.
Professor Robert Dubrow
The project’s goal is to quantify the proportion of typhoid fever cases in Kathmandu that are attributable to climatic variation using time series and mechanistic modeling approaches. There is strong evidence to support a link between climate and the incidence of enteric diseases in Kathmandu.
Cases of typhoid fever typically peak in June-August during the rainy season. There is evidence that the transmission of the disease in Kathmandu is primarily water-borne. Drinking water contamination, including the presence fecal matter, correlated with weekly rainfall over a one-year study led by Stephen Baker, a collaborator based at the Oxford University Clinical Research Unit in Vietnam. However, more research is needed to understand the long-term patterns and quantify the relationship between climate and typhoid incidence.
More in-depth study, using statistical and mathematical methods and better hydrological metrics, can help to assess when, where and why the changes predicted by climate models will impact water-borne enteric disease risk, the research team said. In the future, they hope to form a multidisciplinary team of epidemiologists, microbiologists, disease modelers and climate scientists to study this piece of the puzzle.
CCHI was created in 2015 and is one of the first programs of its kind. It includes new courses that will debut this fall, two doctoral training positions, a case study on climate change and health for the M.P.H. core curriculum, a leadership training workshop for students, a climate change leader in residence, summer internships for students, a speaker series and pilot research grants for faculty. The expectation is that these small grants will provide preliminary data to inform development of a larger project that can compete successfully for external funding.
The program was made possible by a $1.3 million grant from the Overlook International Foundation.