The Michigan Department of Health and Human Services is reporting an increase of Legionnaires’ disease (LD) in Genesee County in summers of 2014 and 2015. While the MDHHS cannot conclude that the increase is related to the water emergency in Flint, the State of Michigan is treating this situation with the same urgency and transparency as the lead response in the city of Flint.

Legionella pneumophila bacteria/CDC
Legionella pneumophila bacteria/CDC

MDHHS has confirmed data through March 2015, and is finalizing preliminary data through November 2015, which indicates an additional increase in cases. From June 2014 to March 2015, 45 LD cases were confirmed in Genesee County, including seven associated fatalities. From May 2015 through November 2015, 42 LD cases, including one case of Pontiac Fever, were reported in Genesee County. There were three associated fatalities. The age range of these individuals was 26–94, with illness onset dates from June 6, 2014 to March 9, 2015 and May 4, 2015 to October 29, 2015.

Legionella is a type of bacteria commonly found in the environment that grows best in warm water, such as hot tubs, cooling towers, hot water tanks, potable water systems, and decorative fountains. When people are exposed to the bacteria, it can cause Legionellosis, a respiratory disease that can infect the lungs and cause pneumonia. The bacteria can also cause a less serious infection called Pontiac fever. Legionella cannot spread from one person to another person.

“While Legionellosis cases are not uncommon, we are concerned about the increase in cases seen in Genesee County,” said Eden Wells, M.D., chief medical executive with the MDHHS. “We are releasing this report and continuing surveillance and investigations to ensure that appropriate actions are being taken to protect the health of the residents of Flint.”

During LD outbreak investigations, clinical specimens are often evaluated against environmental specimens to aid in determining an infection source.  One reason that the increase in cases cannot be directly related to the change in Flint water supply is due to the lack of clinical Legionella isolates from case patients. Clinical isolates are necessary to interpret the findings of an environmental investigation in an outbreak.

In the fall of 2014, MDHHS noticed an increase in people with LD and offered assistance to Genesee County Health Department (GCHD) with case investigations to determine exposures. In January of 2015, MDHHS stepped in to coordinate GCHD’s response. By April 2015, MDHHS had developed an interview questionnaire and began conducting case investigations to look at travel, work, and locations visited during the two weeks prior to symptom onset. These two weeks are considered the incubation period for LD.

Of the confirmed first 45 cases, the source of water at the primary residence was City of Flint water for 47 percent of cases. When looking at additional community sources, more than half of the individuals had a healthcare facility exposure in the two weeks prior to their illness onset and the facility has since implemented multiple environmental and procedural measures to alleviate the situation. Preliminary data from May through November 2015 regarding case investigation information is being finalized and will be released soon.

Ten people had no exposure to a Flint hospital in the two weeks prior to illness nor were their homes on the Flint water system. Other possible exposures were evaluated and no other known community exposures were identified. Enhanced surveillance has continued for the remainder of 2015 and into 2016.

MDHHS has been and continues to work with the Michigan Department of Environmental Quality (DEQ), Centers for Disease Control and Prevention (CDC) and the Environmental Protection Agency (EPA) on this matter. MDHHS shared an initial report with federal partners in June 2015, and initiated and has continued to facilitate regular communication with our federal partners and GCHD to monitor cases.

Vigilant legionellosis awareness and surveillance is occurring in Genesee County. MDHHS informed hospitals in Genesee County of the increase of cases in January 2015, as well as recommended actions on their part throughout all of 2015. MDHHS has also recommended that the GCHD work with the clinical community in Genesee County to assist in LD surveillance through accurate identification, testing, and reporting of all suspect cases.

Most people exposed to Legionella do not become ill. People at higher risk of getting sick include: individuals over 50 years old; current or former smokers; those with chronic lung disease; people with a weakened immune system from diseases like cancer, diabetes, or kidney failure; and individuals who take medications that weaken the immune system, such as steroids or chemotherapy.