Since 2000, the number of reported cases of Legionnaire’s disease in the United States has jumped from about 1,000 to nearly 10,000 in 2018. The reported number could be well below the actual number, as the disease may be underdiagnosed. Special testing is required to determine whether a person has Legionnaire’s disease, as opposed to other strains of bacterial pneumonia, and those tests aren’t always conducted or aren’t even available in some countries. Some researchers estimate as many as 70,000 or even 100,000 people in the U.S. get the disease each year.
Similar to Legionnaires’ disease, but not as severe, Pontiac fever is a flu-like illness that’s also associated with Legionella bacteria. In 1968, workers at the county health department Pontiac, Michigan came down with flu symptoms, but not pneumonia. After the discovery of Legionnaires’ disease, blood samples from the Pontiac workers were re-examined and it was determined that their illness had been caused by the same bacteria. Victims of Pontiac fever typically recover in 1-3 days with no treatment. Because it resolves itself, Pontiac fever is never reported or goes undiagnosed, so it’s more widespread than records show.
Today, in light of building closures and slowdowns during COVID-19, the risk of Legionnaire’s disease and Pontiac fever rises. When buildings sit idle, the plumbing and HVAC systems are typically turned off to save money. This results in warm, stagnant water sitting in the systems, creating a breeding ground for bacteria. When workers come back and the systems are turned on, the bacteria can be distributed throughout the building. Even some of the buildings leased by the CDC were found to contain Legionella bacteria in their water sources after being closed for several months during the pandemic. Those buildings are undergoing remediation to ensure the bacteria is removed before workers return.
What is Legionnaires’ disease?
Legionnaires’ disease is a type of pneumonia, or lung infection, with symptoms that include cough, shortness of breath, muscle aches, headaches and fever, caused by Legionella pneumophila bacteria. Most healthy people are not affected by the bacteria, but those who are over 50 years old, current and former smokers, people with weakened immune systems and those with chronic disease are at higher risk. Most people recover when hospitalized and treated with antibiotics, but about 10% of those who get the disease die from it.