Waterborne Disease Outbreaks Associated With Environmental and Undetermined Exposures to Water – United States, 2013-2014: Selected Outbreak Descriptions

This table provides a description of a selected outbreak presented in Outbreaks associated with environmental and undetermined water exposures — United States, 2013–2014 (MMWR Weekly).

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

Environmental Exposure to Water
Month Year State/Jurisdiction in which outbreak occurred Etiology No. of cases (deaths) Description of outbreak
October 2014 Colorado Giardia duodenalis 9 During a multi-day college field trip, students backpacked through several parks. Lake water and stream water were used for drinking following treatment with liquid iodine drops. Participants reported following package instructions. However, epidemiologic interviews revealed that the amount of time that the water was treated might not have been sufficient to inactivate Giardia. Iodine treatment has low to moderate effectiveness against Giardia, and can be less effective depending on treatment duration, water temperature, turbidity, pH, and other factors.  Appropriate treatment can help to prevent illness associated with ingestion of backcountry water. The CDC provides information on how to ensure safe drinking water while camping, hiking, or traveling here.
January 2013 Illinois Pseudomonas aeruginosa 30 Thirty people were diagnosed with skin infections caused by Pseudomonas aeruginosa after receiving upper ear piercings at a tattoo and piercing facility. The clinical strain of P. aeruginosa was isolated from a spray bottle filled with dilute soap, on the cap threads of the spray bottle, in a bottle of isopropyl alcohol, and in a gallon container of soap. Tap water was used to refill the soap bottles, which were not cleaned between fills. Proper decontamination of containers used to store and dispense water is crucial for preventing illnesses and outbreaks caused by Pseudomonas and other waterborne disease pathogens. Upper ear piercings are especially susceptible to infectious complications due to lack of blood flow to the cartilage of the upper ear. The facility was temporarily closed while the investigation was being conducted. An additional case was reported after the facility reopened, leading to the discontinuation of all upper ear cartilage piercings at the facility.
August 2014 Ohio Legionella pneumophila serogroup 1 22 A contaminated air handler system at a religious center resulted in 22 cases of legionellosis. An air handler is an indoor heating and cooling unit, typically connected to the HVAC system. Environmental testing revealed that a sump pit associated with the air handler was the only source of Legionella in the building and that the strain matched clinical isolates from six case-patients. Investigation comments suggest several contributing factors, including pump discharge failure, water temperature reaching prime Legionella growth range, and high levels of humidity resulting in longer suspension of water droplets from the HVAC system in the environment. The health department was able to distribute an illness survey to the congregation in collaboration with religious center leadership.
Undetermined Exposure to Water
Month Year State/Jurisdiction in which outbreak occurred Etiology No. of cases (deaths) Description of outbreak
July 2014 Montana Cryptosporidium sp. 11 Multiple members of the same swim team became ill with an identical subtype of Cryptosporidium. While the outbreak exposure was determined to involve recreational water activities, it could not be classified more specifically as a treated or untreated recreational water exposure. The epidemiologic investigation identified multiple shared recreational exposures, which included team practices at a reservoir, lake, and swimming pool during the incubation period. Further environmental investigation was unable to identify which water exposure was the source of the Cryptosporidium.
June 2014 Kentucky Legionella pneumophila 6 Six cases of legionellosis were reported to the local health department by a long term care facility following an increase in pneumonia cases and a confirmed case of legionellosis. Although the illnesses were epidemiologically linked to the facility, a common water exposure was not identified. Water testing from multiple water sources at the facility was negative for Legionella, though delays in completing this testing may have contributed to these negative findings.