Waterborne Disease Outbreaks Associated With Environmental and Undetermined Exposures to Water – United States, 2011-2012: Selected Outbreak Descriptions

This table provides a description of a selected outbreak presented in Outbreaks associated with environmental and undetermined water exposures — United States, 2011–2012 (MMWR Weekly).

Description of a Selected Waterborne Disease Outbreak Associated with Environmental & Undetermined Water Exposures, United States, 2011-2012

Environmental or Undetermined Exposure to Water
Month Year State/Jurisdiction in which outbreak occurred Etiology No. of cases (deaths) Description of outbreak
August 2012 Illinois Legionella pneumophila serogroup 1 56 Forty people attending a convention at a hotel became ill with fever or GI symptoms, and a waterborne exposure was suspected. Although no clinical specimens tested positive, two samples taken from the hotel’s ornamental fountain contained Legionella, one of which was L. pneumophila serogroup 1. An epidemiologic investigation among employees identified 16 additional cases and showed that those who worked near the fountain were 4.7 times (95% CI: 1.1–20.6) more likely to have become ill than those who worked farther from the fountain. Taken together, reported symptoms, lack of culture-confirmed L. pneumophila in clinical specimens and presence of Legionella in the fountain indicate that individuals were likely ill with Pontiac Fever, an illness milder than Legionnaire’s Disease that is also caused by Legionella bacteria.