Abstract
BackgroundAlthough the incidence of legionellosis throughout North America and Europe continues to increase, public health investigations have not been able to identify a common exposure in most cases. Over 80% of cases are sporadic with no known source. To better understand the role of the macro-environment in legionellosis risk, a retrospective ecological study assessed associations between population-level measures of demographic, socioeconomic, and environmental factors and high-risk areas.MethodsGeographic variability and clustering of legionellosis was explored in our study setting using the following methods: unadjusted and standardized incidence rate and SaTScan™ cluster detection methods using default scanning window of 1 and 50% as well as a reliability score methodology. Methods for classification of “high-risk” census tracts (areas roughly equivalent to a neighborhood with average population of 4000) for each of the spatial methods are presented. Univariate and multivariate logistic regression analyses were used to estimate associations with sociodemographic factors: population ≥ 65 years of age, non-white race, Hispanic ethnicity, poverty, less than or some high school education; housing factors: housing vacant, renter-occupied, and built pre-1950 and pre-1970; and whether drinking water is groundwater or surface water source.ResultsCensus tracts with high percentages of poverty, Hispanic population, and non-white population were more likely to be classified as high-risk for legionellosis versus a low-risk census tract. Vacant housing, renter-occupied housing, and homes built pre-1970 were also important positively associated risk factors. Drinking water source was not found to be associated with legionellosis incidence.DiscussionCensus tract level demographic, socioeconomic, and environmental characteristics are important risk factors of legionellosis and add to our understanding of the macro-environment for legionellosis occurrence. Our findings can be used by public health professionals to target disease prevention communication to vulnerable populations. Future studies are needed to explore the exact mechanisms by which these risk factors may influence legionellosis clustering.
Highlights
The incidence of legionellosis throughout North America and Europe continues to increase, public health investigations have not been able to identify a common exposure in most cases
Legionellosis refers to two syndromes caused by bacteria of the genus Legionella including: (1) Legionnaires’ disease, which is the more severe form of the infection and associated with pneumonia; and (2) Pontiac fever, which is milder and not associated with pneumonia [8]
To best classify census tracts at “high-risk” for legionellosis we explored the following spatial variability methods: (1) unadjusted and standardized incidence ratios across census tracts; (2) cluster detection with minimum and maximum window scanning and a reliability score method for classification of homogenous, reliable legionellosis clusters
Summary
The incidence of legionellosis throughout North America and Europe continues to increase, public health investigations have not been able to identify a common exposure in most cases. Legionellosis refers to two syndromes caused by bacteria of the genus Legionella including: (1) Legionnaires’ disease, which is the more severe form of the infection and associated with pneumonia; and (2) Pontiac fever, which is milder and not associated with pneumonia [8]. Legionellosis is not transmitted between individuals or by swallowing contaminated water; aspiration is an important mode of disease transmission. Legionella species are common worldwide in the natural environment, including rivers, streams, and lakes and in artificial water environments and can survive in a range of environmental conditions, but grows best in warm temperatures between 32 and 42 °C (90–108 F) [1]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
