2011/01/01 by Sammy Zahran, Shawn P. McElmurry, Paul E. Kilgore +6 · 4 citations
Arts and Humanities · Biochemistry, Genetics and Molecular Biology · Environmental Science · #Cinema History and Criticism #Fecal contamination and water quality #Indoor Air Quality and Microbial Exposure #Legionella and Acanthamoeba research #Media, Journalism, and Communication History #Spanish Culture and Identity
paper · doi:10.1073/pnas.1718679115
openalex publication_date 2011/01/01 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/01
The 2014-2015 Legionnaires' disease (LD) outbreak in Genesee County, MI, and the outbreak resolution in 2016 coincided with changes in the source of drinking water to Flint's municipal water system. Following the switch in water supply from Detroit to Flint River water, the odds of a Flint resident presenting with LD increased 6.3-fold (95% CI: 2.5, 14.0). This risk subsided following boil water advisories, likely due to residents avoiding water, and returned to historically normal levels with the switch back in water supply. During the crisis, as the concentration of free chlorine in water delivered to Flint residents decreased, their risk of acquiring LD increased. When the average weekly chlorine level in a census tract was <0.5 mg/L or <0.2 mg/L, the odds of an LD case presenting from a Flint neighborhood increased by a factor of 2.9 (95% CI: 1.4, 6.3) or 3.9 (95% CI: 1.8, 8.7), respectively. During the switch, the risk of a Flint neighborhood having a case of LD increased by 80% per 1 mg/L decrease in free chlorine, as calculated from the extensive variation in chlorine observed. In communities adjacent to Flint, the probability of LD occurring increased with the flow of commuters into Flint. Together, the results support the hypothesis that a system-wide proliferation of legionellae was responsible for the LD outbreak in Genesee County, MI.