A Legionnaires' disease outbreak in Hopkins, Minn., that killed one person and sickened 22 others, has been linked to cooling towers at Citrus Systems, a beverage manufacturer in Hopkins.
Minnesota Department of Health investigation found Legionella growing in one of Citrus Systems' two cooling towers, and the strain was an exact match with Legionella strains pulled from four patients.
Other cooling towers in the area were sampled, but did not have the specific Legionella strain that caused this outbreak.
"The lab testing is highly specific and provides us with great confidence that this tower is the source of infection," said MDH Deputy State Epidemiologist Richard Danila, PhD.
Citrus Systems' cooling towers were chemically cleaned and disinfected on Sept. 27. The business had a management plan in place for its cooling towers. "We don't know in this case exactly what went wrong to cause the buildup of Legionella," Dr. Danila said. "This situation clearly demonstrates how difficult it can be to keep systems free of Legionella, even when they are well-maintained."
Of the 23 people who contracted Legionnaires' disease in this outbreak, 17 were hospitalized and one died. No new illness has been reported since Sept. 22.
Legionella is found naturally in fresh water environments, but can cause issues when found in human-made water systems, according to the CDC. People can contract Legionnaires' disease when they breathe in a mist contaminated with the bacteria.