Association of Natural Waterways and Legionella pneumophila Infection in Eastern Wisconsin: A Case-Control Study

Authors

Hannah M. William, Advocate Aurora Health; Center for Urban Population Health; University of Wisconsin School of Medicine and Public HealthFollow
Kayla Heslin, Advocate Aurora Health; Center for Urban Population HealthFollow
Jessica J. F. Kram, Advocate Aurora Health; Center for Urban Population Health; University of Wisconsin School of Medicine and Public HealthFollow
Caroline P. Toberna, Advocate Aurora Health; Center for Urban Population HealthFollow
Dennis J. Baumgardner, Advocate Aurora Health; Center for Urban Population Health; University of Wisconsin School of Medicine and Public HealthFollow

Publication Date

4-18-2022

Keywords

Legionella, pneumonia, bacteria, fresh water, waterways, Legionnaire’s disease, environment

Abstract

Preliminary research has suggested possible associations between natural waterways and Legionella infection, and we previously explored these associations in eastern Wisconsin using positive L. pneumophila serogroup 1 urine antigen tests (LUAT) as diagnostic. This case-control study was a secondary analysis of home address data from patients who underwent LUAT at a single eastern Wisconsin health system from 2013 to 2017. Only zip codes within the health system’s catchment area that registered ≥ 3 positive cases and ≥ 50 completed tests, as well as geographically adjacent zip codes with ≥ 2 positive cases and ≥ 50 tests, were included. A 1:3 ratio of cases to randomly selected controls was used. Home addresses were geocoded and mapped using ArcGIS software (Esri); nearest waterway and distance to home was identified. Distance to nearest waterway according to ArcGIS was verified/corrected using Google Maps incognito. Distances were analyzed using chi-squared and 2-sample t-tests. Overall, mean distance to nearest waterway did not differ between cases (2958 ± 2049 ft) and controls (2856 ± 2018 ft; P = 0.701). However, in a subset of nonurban zip codes, cases were closer to nearest waterway than controls (1165 ± 905 ft vs 2113 ± 1710 ft; P = 0.019). No association was found between cases and type of waterway. Further research is needed to investigate associations and differences between natural and built environmental water sources in relation to legionellosis.

Recommended Citation

William HM, Heslin K, Kram JJ, Toberna CP, Baumgardner DJ. Association of natural waterways and Legionella pneumophila infection in eastern Wisconsin: a case-control study. J Patient Cent Res Rev. 2022;9:128-31. doi: 10.17294/2330-0698.1872