The Minnesota Department of Health says that 23 people who live or work in Hopkins have contracted Legionnaires’ Disease. Three more cases were confirmed by MDH between September 28 and September 30, 2016. The most recent illness onset date is September 22.
According to that news release, seven cooling towers in that city are being investigated in connection to this outbreak. As of September 29, 2016, all of those cooling towers have been or are being remediated by their owners. Remediation is complex and can consist of heating the water in the building’s system to 157°F, draining tanks, cleaning them, chlorination, and frequent re-testing.
Interviews with patients or their family members didn’t uncover a common exposure, such as visits to a restaurant, store, or specific building. The only commonality is spending time in Hopkins, a suburb of Minneapolis. The pattern of cases is consistent with a community-wide exposure to contaminated water that aerosolized.
Environmental samples from those cooling towers have been collected and testing is underway. Since the legionella bacteria grows so slowly, testing in the laboratory can take weeks.
The investigation will continue until “all nearby cooling towers that could be a source of the Hopkins illnesses are identified and remediated, and no additional cases are identified,” according to the press release. The press release also states that cooling towers are not regulated in Minnesota and that no state or local registry of master list of cooling towers exists, which makes identification of those structures difficult in an outbreak.
A Legionnaires’ Disease outbreak in the South Bronx in New York City prompted the city to enact new laws regulating cooling towers. In that outbreak in the summer of 2015, 128 people were sickened, and 12 people died.
From 2012 through 2015, there were about 58 people with confirmed cases of Legionnaires’ disease in Minnesota. As of late September, 2016, more than 90 cases have been confirmed in that state. Most of these cases occur in late summer and early fall.
Water that sits in cooling towers, especially those in large and older buildings, can harbor the legionella bacteria. That bacteria aerosolizes in mist from cooling towers, fountains, hot water tanks, whirlpool spas, plumbing systems, and air conditioning structures. People breathe in the mist and can then get sick.
Most people who are exposed to this bacteria do not get sick. Those who are most at risk for this infection are those over the age of 50, smokers, and people with chronic lung disease and weakened immune systems.
The symptoms of Legionnaires’ Disease include fever, chills, headaches, muscle aches, fatigue, shortness of breath, cough, mental confusion, diarrhea, and vomiting. This illness is most often diagnosed as pneumonia, but when a group of people living in the same area or building complex present with these symptoms, tests for Legionnaires’ Disease are conducted.
The illness is treatable with antibiotics, although the mortality rate is high, ranging from 5 to 30%. The earlier the infection is treated, the better the possible outcome. If you live or work in Hopkins, Minnesota and have experienced these symptoms, see your doctor and ask for a Legionnaires’ test.