Michigan is experiencing an outbreak of Legionnaires’ disease. The bacterial pneumonia is common in areas where moisture and water vapor could be contaminated. “Transmission to people occurs when mist or vapor containing the bacteria is inhaled. Legionnaires’ disease does not spread person to person.¹ According to Michigan Department of Health and Human Services:
“Between July 1 and July 14, 107 cases of Legionnaires disease have been reported in 25 counties. This represents a 569% increase from referrals from the same period in 2020 (16 cases) and a 161% increase from referrals from the same period in 2019 (41 cases).”¹
At the time of writing, no common cause or source has been linked to the wide-spread uptick in cases.¹
What is Legionnaires’?
A serious form of pneumonia, Legionnaires’ has symptoms that closely resemble COVID including headache, shortness of breath, fever, and muscle aches. Legionnaires’ is a bacterial disease that requires prompt attention.
Legionnaires’ disease is contracted when people inhale the vapor containing the bacteria which causes the disease. According to Mayo Clinic:
“The bacterium Legionella pneumophila is responsible for most cases of Legionnaires’ disease. Outdoors, legionella bacteria survive in soil and water, but rarely cause infections. However, legionella bacteria can multiply in water systems made by humans, such as air conditioners.”²
Recent Concerns Regarding Legionnaires and Outbreaks
In January, an apartment community for seniors experienced an outbreak of 10 cases of Legionnaires’, with one death. While residents were moved to other housing, and significant testing and mitigation was done, no cause could be found. Residents were moved back into their homes, to have two more fall ill with Legionnaires’. With these two additional cases, still no common cause has been found.³
There have been several other cases all over the world, many with no common cause found. Typically, Legionnaires’ is most common during summer-early fall. In Northern Portugal, 88 cases had been confirmed late October 2020-January 2021. Cooling towers were disinfected, though no cause was confirmed. Fifteen of the cases ended in death.⁴
Israel, Montreal, England, and prisons in the U.S. have all had unconfirmed outbreaks outside of the typical time frame Legionnaires’ would be a concern.
Legionnaires’ and COVID
There are some organizations concerned with the rise of Legionnaires’ while COVID is still on the forefront of medical headlines.
According to BMC (BioMed Central), a peer-reviewed medical journal:
“Pneumonia is the most common manifestation of both Legionnaires’ disease and COVID-19, and initial presentation for both may include fever, headache, confusion, dyspnea, nausea, and diarrhea. Individual risk factors for both Legionnaires’ disease and severe COVID-19 include older age, diabetes, and chronic lung disease. The incubation period for Legionnaires’ disease is about 5 to 6 days but may range from 2 to 14 days, similar to COVID-19.”⁵
“Because clinical manifestations may be indistinguishable between COVID-19 and Legionnaires’ disease, targeted microbiologic testing for both Legionella and SARS-CoV2 are essential.”⁵
Reopening From Shutdowns and Legionnaires’
With so many buildings having been shut down, lower capacities due to people working or studying from home, there are other concerns. Water has been sitting stagnant in heating and air conditioning systems as well as plumbing. As these buildings reopen, and people begin to go back to the workplace or schools, proper and costly preparations need to be taken to ensure water vapor and air quality is safe.⁶