Michigan reported a significant increase in Legionnaires’ disease across 25 counties
Michigan saw a significant increase in Legionnaires’ disease cases in the first two weeks of July compared to the same time last year.
The Michigan Department of Health and Human Services noted that 107 cases reported in 25 counties between July 1 and July 14 were “higher than expected for Michigan at this time of year.” The two-week total represents a 569% increase from the 16 cases reported in the same time period in 2020. There were 41 cases during the same two weeks in 2019.
The state Department of Health notes that some environmental factors, such as precipitation and heat, can exacerbate legionnaires’ proliferation.
“Recent weather trends including rain, flooding and warmer weather may play a role in the rise in Legionnaires’ disease cases this summer,” Dr. Johnny Khaldoon, the state’s chief medical officer, said in a statement. “We want everyone to be aware of Legionnaire’s disease, especially if they are at higher risk of contracting the disease and we ask health care providers to remain vigilant, and to be tested and treated appropriately.”
While the increase is “alarming,” the total number of cases in the first two weeks of July is low compared to the population, said Chuanwu Shi, professor of environmental health sciences and global public health at the University of Michigan’s School of Public Health. .
“I don’t think you really need to be afraid,” Shi said, but the increase “is an indication that something is wrong here in the system.”
Without a known common source and with cases spreading across the state, it’s hard to pinpoint the cause of the increase, said Joseph Eisenberg, professor and chair of the department of epidemiology at the University of Michigan.
“In this case, it looks like it might be a change in the environment,” Eisenberg said. “…it’s pervasive. It’s not like it’s an obvious source.”
The highest case prevalence is reported in Michigan’s three most populous counties, with Wayne, Oakland and Macomb counties accounting for 68, or 64%, of the state’s cases. The remaining cases are spread in 22 other counties.
17 cases have been reported in Detroit, Wayne County 19, Oakland County 17 and Macomb County 15.
The country was unable to identify any common sources of infection, according to a statement on Monday. The 107 cases identified in early July did not result in any deaths.
According to the state, Legionella bacteria decompose best in the heat of summer and early fall and in stagnant water. As buildings reopen after the pandemic, they can also be a source of exposure for bacterial growth.
“These big office buildings that aren’t much used in pandemic season — there’s a lot of standing water in the pipes,” Shi said, where bacteria can grow.
Legionella bacteria can cause two types of infection — a mild form called Pontiac fever and Legionnaires’ disease, which includes symptoms such as fever, cough and pneumonia, according to the state health department.
The state is working to inform health care providers of the increase, and they said doctors should consider the increase if a patient has pneumonia or is at risk of infection.
The infection is not transmitted from person to person, but is transmitted by inhalation of vapor or droplets containing bacteria.
People at risk for infection include smokers, people with lung disease, people with weakened immune systems or people over 50 years old. Exposure risk also increases if individuals have recently resided in a health care facility, had plumbing repairs or were recently exposed to hot tubs.
The disease is “opportunistic,” Eisenberg said, meaning that it usually affects those with other underlying conditions. But it is easily treated with antibiotics.
“If you are immunocompromised in any way, you should be more concerned,” he said. “A lot of people are asymptomatic, and people with comorbidities are the ones who really get sick.”
The bacteria are found in streams and lakes naturally, according to the state. But they can also be found in man-made water systems, especially if they are stagnant and not cleaned regularly. Man-made water systems that pose a risk include cooling towers, fountains, whirlpool spas, and drinking water systems.
One of the most well-known cases of Legionnaires’ outbreak is related to the Flint water crisis and the 2014-2015 outbreak in the region that infected more than 90 people and killed at least 12 people.
The researchers concluded that chlorine levels added to the city’s water supply were not sufficient to combat the spread of Legionella that followed the 2014 shift of the city’s water to the Flint River.
But the government did not immediately notify the public. A Detroit News review of state and Genesee County emails found that six U.S. Environmental Protection Agency officials were told in late March 2015 that the state would alert the public about the rise in veteran cases. Two months later, there was no announcement, and an email a Michigan health official sent to the Centers for Disease Control and Prevention declared that the outbreak was “over.”
It wasn’t until January 13, 2016, when Gov. Rick Snyder announced the Legion’s outbreak for the first time to the public at a hastily arranged press conference in Detroit. Snyder now faces misdemeanor charges for decisions made about Flint while he was leading the state.