Is There a Legionnaire's Epidemic Brewing in the United States?

The impact of the water crisis in Flint, Michigan now includes an infectious disease component—namely, an outbreak of Legionnaire’s disease—and it has sparked a debate among health officials and infectious disease experts as to when the public should be notified about an outbreak and how to best coordinate response.

On April 11, USA Today and the Detroit Free Press reported that more than 80 people in the central Michigan city were diagnosed with the disease during a 17-month period between 2014 and 2015, after the source of its water supply was switched from Lake Huron to the Flint River in April 2014. At least 10 people died after being diagnosed.

Officials have not directly linked the outbreak of Legionnaire’s in the Flint area to the water supply, which has been found to contain lead and other contaminants. However, it has added to the already smoldering tensions that have gripped the city—and the nation—since the public became aware of the problems with the city’s water supply. News of the outbreak wasn’t made public until January, despite the fact that emails obtained from Governor Rick Snyder’s administration suggest that local, state and federal officials were aware of it months earlier.

At present, there is no federal requirement to notify the public about a Legionnaire’s outbreak; however, the Centers for Disease Control and Prevention (CDC) recommends notification once the source of the outbreak has been identified and confirmed.

“For example, if a hotel’s water system is confirmed to be the source of an outbreak, we would encourage that hotel to inform people who recently stayed at the hotel and those who have upcoming reservations about the situation, so that those people know what to do if they develop pneumonia symptoms or can choose to change their hotel reservations if they haven’t yet traveled,” an agency spokesperson told Contagion. “CDC also encourages the state and local public health officials who are investigating the outbreak to alert healthcare providers in their community to test for Legionnaires’ disease in patients with pneumonia who may have been exposed to the outbreak source during their incubation period.”

The crisis in Flint has led to renewed scrutiny of lead contamination in drinking water nationally. In New York, for example, an Associated Press (AP) review of Environmental Protection Agency data revealed that 82 public and private drinking water systems in the state have had lead levels in excess of the federal action limit at least once since 2013. The affected systems included those supplying water to 16 schools and/or daycare centers.

The same audit found that 39 of 1,082 water systems in Connecticut had tested over the limit during the same period. The systems served schools, office parks, a state office and several apartment complexes. Meanwhile, in Newark, New Jersey, city officials shut off the water supply to 30 schools in the city after tests yielded unsafe lead levels. Free blood tests were offered to more than 17,000 students in the city to check for lead poisoning.

Nationally, some 1,400 water systems supplying water to more than 10 million people have been shown to violate federal lead standards between 2013 and September 2015, according to the AP audit. Although no amount of lead in drinking water is considered safe, federal regulations call for supply systems to maintain levels below 15 parts per billion.

From 2011-2012, the most recent period for which data are available, there were 18 outbreaks of Legionnaire’s connected to water exposures reported in 11 states, according to the CDC. In New York, an outbreak connected to a contaminated cooling tower in the Bronx affected 120 people, causing 12 deaths.

Brian P. Dunleavy is a medical writer and editor based in New York. His work has appeared in numerous healthcare-related publications. He is the former editor of Infectious Disease Special Edition.