{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,10,19]],"date-time":"2026-10-19T09:59:57Z","timestamp":1792403997210,"version":"4.4.0"},"reference-count":28,"publisher":"National Academy of Sciences","issue":"8","license":[{"start":{"date-parts":[[2018,8,5]],"date-time":"2018-08-05T00:00:00Z","timestamp":1533427200000},"content-version":"vor","delay-in-days":181,"URL":"http:\/\/www.pnas.org\/site\/aboutpnas\/licenses.xhtml"}],"funder":[{"DOI":"10.13039\/100009931","name":"Michigan Department of Health and Human Services","doi-asserted-by":"publisher","award":["20163753-00"],"award-info":[{"award-number":["20163753-00"]}],"id":[{"id":"10.13039\/100009931","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/100000002","name":"HHS | National Institutes of Health","doi-asserted-by":"publisher","award":["R21 ES027199-01"],"award-info":[{"award-number":["R21 ES027199-01"]}],"id":[{"id":"10.13039\/100000002","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":["www.pnas.org"],"crossmark-restriction":true},"short-container-title":["Proc. Natl. Acad. Sci. U.S.A."],"published-print":{"date-parts":[[2018,2,20]]},"abstract":"<jats:p>The 2014\u20132015 Legionnaires\u2019 disease (LD) outbreak in Genesee County, MI, and the outbreak resolution in 2016 coincided with changes in the source of drinking water to Flint\u2019s 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 &lt;0.5 mg\/L or &lt;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.<\/jats:p>","DOI":"10.1073\/pnas.1718679115","type":"journal-article","created":{"date-parts":[[2018,2,5]],"date-time":"2018-02-05T15:20:12Z","timestamp":1517844012000},"update-policy":"https:\/\/doi.org\/10.1073\/pnas.cm10313","source":"Crossref","is-referenced-by-count":78,"title":["Assessment of the Legionnaires\u2019 disease outbreak in Flint, Michigan"],"prefix":"10.1073","volume":"115","author":[{"given":"Sammy","family":"Zahran","sequence":"first","affiliation":[{"name":"Department of Economics, Colorado State University, Fort Collins, CO 80523;"},{"name":"Department of Epidemiology, Colorado School of Public Health, Fort Collins, CO 80523;"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Shawn P.","family":"McElmurry","sequence":"additional","affiliation":[{"name":"Department of Civil &amp; Environmental Engineering, Wayne State University, Detroit, MI 48202;"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Paul E.","family":"Kilgore","sequence":"additional","affiliation":[{"name":"Department of Pharmacy Practice, Wayne State University, Detroit, MI 48201;"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"David","family":"Mushinski","sequence":"additional","affiliation":[{"name":"Department of Economics, Colorado State University, Fort Collins, CO 80523;"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Jack","family":"Press","sequence":"additional","affiliation":[{"name":"Department of Civil &amp; Environmental Engineering, Wayne State University, Detroit, MI 48202;"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Nancy G.","family":"Love","sequence":"additional","affiliation":[{"name":"Department of Civil &amp; Environmental Engineering, University of Michigan, Ann Arbor, MI 48109;"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Richard C.","family":"Sadler","sequence":"additional","affiliation":[{"name":"Department of Family Medicine, Michigan State University, Flint, MI 48502;"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-2542-0266","authenticated-orcid":false,"given":"Michele S.","family":"Swanson","sequence":"additional","affiliation":[{"name":"Department of Microbiology and Immunology, University of Michigan, Ann Arbor, MI 48109"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"341","published-online":{"date-parts":[[2018,2,5]]},"reference":[{"key":"e_1_3_4_1_2","doi-asserted-by":"crossref","first-page":"842","DOI":"10.15585\/mmwr.mm6431a2","article-title":"Surveillance for waterborne disease outbreaks associated with drinking water\u2014United States, 2011\u20132012","volume":"64","author":"Beer KD","year":"2015","unstructured":"KD Beer, , Surveillance for waterborne disease outbreaks associated with drinking water\u2014United States, 2011\u20132012. MMWR Morb Mortal Wkly Rep 64, 842\u2013848 (2015).","journal-title":"MMWR Morb Mortal Wkly Rep"},{"key":"e_1_3_4_2_2","doi-asserted-by":"crossref","first-page":"2003","DOI":"10.1017\/S0950268811002858","article-title":"Direct healthcare costs of selected diseases primarily or partially transmitted by water","volume":"140","author":"Collier SA","year":"2012","unstructured":"SA Collier, , Direct healthcare costs of selected diseases primarily or partially transmitted by water. Epidemiol Infect 140, 2003\u20132013 (2012).","journal-title":"Epidemiol Infect"},{"key":"e_1_3_4_3_2","doi-asserted-by":"crossref","first-page":"135","DOI":"10.1016\/j.watres.2017.03.031","article-title":"Potential impacts of changing supply-water quality on drinking water distribution: A review","volume":"116","author":"Liu G","year":"2017","unstructured":"G Liu, , Potential impacts of changing supply-water quality on drinking water distribution: A review. Water Res 116, 135\u2013148 (2017).","journal-title":"Water Res"},{"key":"e_1_3_4_4_2","doi-asserted-by":"crossref","first-page":"843","DOI":"10.1016\/j.scitotenv.2017.02.164","article-title":"A discussion about public health, lead and Legionella pneumophila in drinking water supplies in the United States","volume":"590","author":"Rosen MB","year":"2017","unstructured":"MB Rosen, LR Pokhrel, MH Weir, A discussion about public health, lead and Legionella pneumophila in drinking water supplies in the United States. Sci Total Environ 590\u2013591, 843\u2013852 (2017).","journal-title":"Sci Total Environ"},{"key":"e_1_3_4_5_2","unstructured":"R Fonger General Motors shutting off Flint River water at engine plant over corrosion worries. MLive . Available at www.mlive.com\/news\/flint\/index.ssf\/2014\/10\/general_motors_wont_use_flint.html. Accessed December 6 2017. (October 13 2014)."},{"key":"e_1_3_4_6_2","doi-asserted-by":"crossref","first-page":"447","DOI":"10.1128\/aem.53.2.447-453.1987","article-title":"Comparative assessment of chlorine, heat, ozone, and UV light for killing Legionella pneumophila within a model plumbing system","volume":"53","author":"Muraca P","year":"1987","unstructured":"P Muraca, JE Stout, VL Yu, Comparative assessment of chlorine, heat, ozone, and UV light for killing Legionella pneumophila within a model plumbing system. Appl Environ Microbiol 53, 447\u2013453 (1987).","journal-title":"Appl Environ Microbiol"},{"key":"e_1_3_4_7_2","doi-asserted-by":"crossref","first-page":"117","DOI":"10.1002\/j.1551-8833.2009.tb09894.x","article-title":"Legionella control by chlorine dioxide in hospital water systems","volume":"101","author":"Zhang Z","year":"2009","unstructured":"Z Zhang, , Legionella control by chlorine dioxide in hospital water systems. J Am Water Works Assoc 101, 117\u2013127 (2009).","journal-title":"J Am Water Works Assoc"},{"key":"e_1_3_4_8_2","doi-asserted-by":"crossref","first-page":"654","DOI":"10.11150\/kansenshogakuzasshi1970.69.654","article-title":"An outbreak of Pontiac fever due to Legionella pneumophila serogroup 7. II. Epidemiological aspects","volume":"69","author":"Yabuuchi E","year":"1995","unstructured":"E Yabuuchi, , An outbreak of Pontiac fever due to Legionella pneumophila serogroup 7. II. Epidemiological aspects. Kansenshogaku Zasshi 69, 654\u2013665 (1995).","journal-title":"Kansenshogaku Zasshi"},{"key":"e_1_3_4_9_2","doi-asserted-by":"crossref","first-page":"390","DOI":"10.3390\/pathogens4020390","article-title":"Environmental (saprozoic) pathogens of engineered water systems: Understanding their ecology for risk assessment and management","volume":"4","author":"Ashbolt NJ","year":"2015","unstructured":"NJ Ashbolt, Environmental (saprozoic) pathogens of engineered water systems: Understanding their ecology for risk assessment and management. Pathogens 4, 390\u2013405 (2015).","journal-title":"Pathogens"},{"key":"e_1_3_4_10_2","doi-asserted-by":"crossref","first-page":"e0134726","DOI":"10.1371\/journal.pone.0134726","article-title":"Effect of common drinking water disinfectants, chlorine and heat, on free Legionella and amoebae-associated Legionella","volume":"10","author":"Cervero-Arag\u00f3 S","year":"2015","unstructured":"S Cervero-Arag\u00f3, S Rodr\u00edguez-Mart\u00ednez, A Puertas-Bennasar, RM Araujo, Effect of common drinking water disinfectants, chlorine and heat, on free Legionella and amoebae-associated Legionella. PLoS One 10, e0134726 (2015).","journal-title":"PLoS One"},{"key":"e_1_3_4_11_2","doi-asserted-by":"crossref","first-page":"950","DOI":"10.1111\/j.1365-2672.2004.02391.x","article-title":"Amoebae in domestic water systems: Resistance to disinfection treatments and implication in Legionella persistence","volume":"97","author":"Thomas V","year":"2004","unstructured":"V Thomas, , Amoebae in domestic water systems: Resistance to disinfection treatments and implication in Legionella persistence. J Appl Microbiol 97, 950\u2013963 (2004).","journal-title":"J Appl Microbiol"},{"key":"e_1_3_4_12_2","doi-asserted-by":"crossref","first-page":"507","DOI":"10.1128\/CMR.00077-09","article-title":"Causes of outbreaks associated with drinking water in the United States from 1971 to 2006","volume":"23","author":"Craun GF","year":"2010","unstructured":"GF Craun, , Causes of outbreaks associated with drinking water in the United States from 1971 to 2006. Clin Microbiol Rev 23, 507\u2013528 (2010).","journal-title":"Clin Microbiol Rev"},{"key":"e_1_3_4_13_2","doi-asserted-by":"crossref","first-page":"749","DOI":"10.1289\/ehp.1408692","article-title":"Epidemiology and ecology of opportunistic premise plumbing pathogens: Legionella pneumophila, Mycobacterium avium, and Pseudomonas aeruginosa","volume":"123","author":"Falkinham JO","year":"2015","unstructured":"3rd JO Falkinham, ED Hilborn, MJ Arduino, A Pruden, MA Edwards, Epidemiology and ecology of opportunistic premise plumbing pathogens: Legionella pneumophila, Mycobacterium avium, and Pseudomonas aeruginosa. Environ Health Perspect 123, 749\u2013758 (2015).","journal-title":"Environ Health Perspect"},{"key":"e_1_3_4_14_2","doi-asserted-by":"crossref","first-page":"538","DOI":"10.1007\/s00248-009-9514-z","article-title":"Legionella, protozoa, and biofilms: Interactions within complex microbial systems","volume":"58","author":"Taylor M","year":"2009","unstructured":"M Taylor, K Ross, R Bentham, Legionella, protozoa, and biofilms: Interactions within complex microbial systems. Microb Ecol 58, 538\u2013547 (2009).","journal-title":"Microb Ecol"},{"key":"e_1_3_4_15_2","volume-title":"Water and Wastewater Engineering: Design Principles and Practice. Professional Edition","author":"Davis ML","year":"2010","unstructured":"ML Davis Water and Wastewater Engineering: Design Principles and Practice. Professional Edition (McGraw-Hill, New York, 2010)."},{"key":"e_1_3_4_16_2","volume-title":"Recommended Standards for Water Works","author":"Great Lakes \u2013 Upper Mississippi River Board of State and Provincial Public Health and Environmental Managers","year":"2012","unstructured":"; Great Lakes \u2013 Upper Mississippi River Board of State and Provincial Public Health and Environmental Managers Recommended Standards for Water Works (Health Research Inc, Albany, NY, 2012)."},{"key":"e_1_3_4_17_2","unstructured":"; World Health Organization Water Safety in Distribution Systems (WHO Geneva). (2014)."},{"key":"e_1_3_4_18_2","doi-asserted-by":"crossref","first-page":"125","DOI":"10.3389\/fcimb.2014.00125","article-title":"Metabolism of the vacuolar pathogen Legionella and implications for virulence","volume":"4","author":"Manske C","year":"2014","unstructured":"C Manske, H Hilbi, Metabolism of the vacuolar pathogen Legionella and implications for virulence. Front Cell Infect Microbiol 4, 125 (2014).","journal-title":"Front Cell Infect Microbiol"},{"key":"e_1_3_4_19_2","unstructured":"P Christensen DA Keiser GE Lade Economic effects of environmental crisis: Evidence from Flint Michigan (Iowa State University Ames IA) Mimeo. (2017)."},{"key":"e_1_3_4_20_2","doi-asserted-by":"crossref","first-page":"160","DOI":"10.1016\/j.envres.2017.05.028","article-title":"Four phases of the Flint water crisis: Evidence from blood lead levels in children","volume":"157","author":"Zahran S","year":"2017","unstructured":"S Zahran, SP McElmurry, RC Sadler, Four phases of the Flint water crisis: Evidence from blood lead levels in children. Environ Res 157, 160\u2013172 (2017).","journal-title":"Environ Res"},{"key":"e_1_3_4_21_2","doi-asserted-by":"crossref","first-page":"76","DOI":"10.1002\/j.1551-8833.2008.tb09748.x","article-title":"Committee report: Disinfection survey, Part 1-Recent changes, current practices, and water quality","volume":"100","author":"American Water Works Association Disinfection Systems Committee","year":"2008","unstructured":"; American Water Works Association Disinfection Systems Committee, Committee report: Disinfection survey, Part 1-Recent changes, current practices, and water quality. J Am Water Works Assoc 100, 76\u201390 (2008).","journal-title":"J Am Water Works Assoc"},{"key":"e_1_3_4_22_2","unstructured":"R Fonger CDC finds first genetic link between Legionnaires\u2019 outbreak Flint water. M Live . Available at www.mlive.com\/news\/flint\/index.ssf\/2017\/02\/cdc_finds_first_genetic_link_b.html. Accessed January 18 2018. (February 16 2017)."},{"key":"e_1_3_4_23_2","doi-asserted-by":"crossref","first-page":"110","DOI":"10.1002\/j.1551-8833.2008.tb09778.x","article-title":"Committee report: Disinfection survey, Part 2-Alternatives, experiences, and future plans","volume":"100","author":"AWWA Disinfection Systems Committee","year":"2008","unstructured":"; AWWA Disinfection Systems Committee, Committee report: Disinfection survey, Part 2-Alternatives, experiences, and future plans. J Am Water Works Assoc 100, 110\u2013124 (2008).","journal-title":"J Am Water Works Assoc"},{"key":"e_1_3_4_24_2","unstructured":"; US Environmental Protection Agency FACTOIDS: Drinking water and ground water statistics for 2007 (US Environmental Protection Agency Office of Water Washington DC) EPA 816-K-07-004. (2008)."},{"key":"e_1_3_4_25_2","doi-asserted-by":"crossref","first-page":"e61036","DOI":"10.1371\/journal.pone.0061036","article-title":"Rainfall is a risk factor for sporadic cases of Legionella pneumophila pneumonia","volume":"8","author":"Garcia-Vidal C","year":"2013","unstructured":"C Garcia-Vidal, , Rainfall is a risk factor for sporadic cases of Legionella pneumophila pneumonia. PLoS One 8, e61036 (2013).","journal-title":"PLoS One"},{"key":"e_1_3_4_26_2","doi-asserted-by":"crossref","first-page":"576","DOI":"10.15585\/mmwr.mm6522e1","article-title":"Vital signs: Deficiencies in environmental control identified in outbreaks of Legionnaires\u2019 disease\u2013North America, 2000\u20132014","volume":"65","author":"Garrison LE","year":"2016","unstructured":"LE Garrison, , Vital signs: Deficiencies in environmental control identified in outbreaks of Legionnaires\u2019 disease\u2013North America, 2000\u20132014. MMWR Morb Mortal Wkly Rep 65, 576\u2013584 (2016).","journal-title":"MMWR Morb Mortal Wkly Rep"},{"key":"e_1_3_4_27_2","doi-asserted-by":"crossref","first-page":"811","DOI":"10.1017\/S0950268806007552","article-title":"Increased rainfall is associated with increased risk for legionellosis","volume":"135","author":"Hicks LA","year":"2007","unstructured":"LA Hicks, , Increased rainfall is associated with increased risk for legionellosis. Epidemiol Infect 135, 811\u2013817 (2007).","journal-title":"Epidemiol Infect"},{"key":"e_1_3_4_28_2","doi-asserted-by":"crossref","first-page":"763","DOI":"10.2105\/AJPH.2017.303692","article-title":"Social and built environmental correlates of predicted blood lead levels in the Flint water crisis","volume":"107","author":"Sadler RC","year":"2017","unstructured":"RC Sadler, J LaChance, M Hanna-Attisha, Social and built environmental correlates of predicted blood lead levels in the Flint water crisis. Am J Public Health 107, 763\u2013769 (2017).","journal-title":"Am J Public Health"}],"updated-by":[{"DOI":"10.1073\/pnas.1808389115","type":"correction","label":"Correction","source":"publisher","updated":{"date-parts":[[2018,6,11]],"date-time":"2018-06-11T00:00:00Z","timestamp":1528675200000}}],"container-title":["Proceedings of the National Academy of Sciences"],"original-title":[],"language":"en","link":[{"URL":"http:\/\/www.pnas.org\/syndication\/doi\/10.1073\/pnas.1718679115","content-type":"unspecified","content-version":"vor","intended-application":"syndication"},{"URL":"https:\/\/pnas.org\/doi\/pdf\/10.1073\/pnas.1718679115","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2022,6,7]],"date-time":"2022-06-07T15:07:47Z","timestamp":1654614467000},"score":1,"resource":{"primary":{"URL":"https:\/\/pnas.org\/doi\/full\/10.1073\/pnas.1718679115"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2018,2,5]]},"references-count":28,"journal-issue":{"issue":"8","published-print":{"date-parts":[[2018,2,20]]}},"alternative-id":["10.1073\/pnas.1718679115"],"URL":"https:\/\/doi.org\/10.1073\/pnas.1718679115","relation":{},"ISSN":["0027-8424","1091-6490"],"issn-type":[{"value":"0027-8424","type":"print"},{"value":"1091-6490","type":"electronic"}],"subject":[],"published":{"date-parts":[[2018,2,5]]},"assertion":[{"value":"2018-02-05","order":2,"name":"published","label":"Published","group":{"name":"publication_history","label":"Publication History"}}]}}