Metro Detroit cases of Legionnaires’ disease were up 143 percent in June and July compared with the same months last year, state health officials announced Friday.

There were 72 cases identified in Wayne, Oakland and Macomb counties in June and July, compared with 30 cases over the same period a year ago. Information on deaths related to the outbreak wasn’t available from the Michigan Department of Health and Human Services on Friday.

“Over half of these cases were reported in June and July of this year and are still undergoing follow-up by the local health departments,” MDHHS spokeswoman Jennifer Eisner said. “Final confirmation of legionella-associated deaths requires review of death certificates for causes of death related to Legionnaires’ disease and/or death within 30 days of discharge.”

For the year through July 31, the state found the largest increase was reported in Macomb County, with 28 cases in 2017, compared with 13 over the same period a year earlier. The state found 33 cases in Wayne and 21 in Oakland, up from 20 and 15, respectively.

Incidents of the disease are most common during the summer and early fall, but the number of cases this year is higher than expected. State health officials Friday said they are working with local health departments to investigate the uptick.

Legionnaires’ disease is caused by legionella bacteria, which is found naturally in fresh-water lakes and streams but can also live in man-made water systems, cooling towers and spas. Transmission can occur when mist or vapor containing the bacteria is inhaled.

In Detroit, where 25 cases were reported through July 31, up from 23 cases a year earlier, concerns continue about the possibility the city’s water shut-offs program may have contributed to a spike in illnesses. Community activists in late July had called for a declaration of a public health emergency in Detroit, saying health officials have ignored a hospital study that found a correlation between water shut-offs and water-related illnesses.

In the study, performed by three Henry Ford researchers using block-level address data, 37,441 cases of water-borne illness in Detroit were analyzed and compared to Detroit addresses where water was shut off during the same time period, officials said.

Patients diagnosed with skin and soft tissue diseases were 1.48 times more likely to live on a block that experienced water shut-offs, officials said on Wednesday.

In Genesee County, some scientists have linked changes in Flint’s water system to an outbreak of Legionnaires’ disease in that region that sickened 91 residents in 2014 and 2015, resulting in 12 deaths.

A February 2016 Detroit News review of 24,000 pages of Flint-related documents among local, state and federal officials found that state officials told six U.S. Environmental Protection Agency officials in March 2015 that they would soon alert the public to the Legionnaires’ outbreak but didn’t.

The state didn’t publicly acknowledge the Legionnaires’ outbreak until a hastily organized press conference in Detroit by Gov. Rick Snyder on Jan. 13, 2016.

More about Legionnaires’ disease

Legionella bacteria are found naturally in fresh water lakes and streams, but can also be found in man-made water systems. Transmission occurs when mist or vapor containing the bacteria is inhaled. Legionellosis does not spread from one person to another.

Risk factors for exposure to legionella bacteria include:

Recent travel with an overnight stay outside of the home

Recent stay in a health care facility

Exposure to hot tubs

Exposure to settings where the plumbing has had recent repairs or maintenance work

Who’s at risk?

Most healthy individuals do not become infected after exposure to Legionella. Individuals at a higher risk of getting sick include:

People over age 50

Current or former smokers

People with chronic lung disease

People with weakened immune systems from diseases, such as cancer, diabetes, or liver or kidney failure

People who take immunosuppressant drugs

For more help

Individuals with any concerns about Legionnaires’ disease should talk to their physician. More information on Legionella and Legionnaires’ disease can be found on the Centers for Disease Control and Prevention website:

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