Effect of Rainfall on Diarrheal Illness on San Cristobal Island, Galapagos (2016)

Undergraduates: Coertney Scoggin, Kelly Houck

Faculty Advisor: Jill Stewart
Department: Biology

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Diarrheal disease remains a leading cause of childhood illness and death in developing countries, and is often due to lack of sanitation systems or lack of efficacy of these systems. In this case, San Cristobal has a water sanitation system, but contaminated water is still reaching homes and businesses. The primary objective of this research is to determine the impacts of rainfall on bacterial contamination of drinking water and incidences of diarrheal illness on San Cristobal Island, Galapagos, Ecuador. I investigated whether precipitation caused disease outbreaks and diarrheal illness based on measures of bacterial contamination of drinking water as well as hospital records from the months of water collection. Based on archival 2013 data, I found that gastrointestinal illness has a correlation with the amount of rain received. The more rain received in millimeters, the higher the incidence of gastrointestinal illness. From the data I collected in summer 2015, I found that rainfall increases contamination most on the day of rainfall. After the initial day of rain, contamination decreases, but can still be present. This has implications all over the tropics because bacterial contamination is the worst on days that it rains. If drinking water can be filtered more or avoided on high contamination days, it could mean lower sickness rates and lower child death rates throughout the tropical region.