In May, the Centers for Disease Control and Prevention (CDC) warned that a period of inactivity in buildings could spur the growth of Legionella. When plumbing systems shut down, water becomes stagnant and chlorine and other disinfectants dissipate. The CDC cautions that when water isn’t in regular use, its temperature can range between 77 and 108 degrees F, which is an ideal breeding condition for bacteria. “As the cold water warms up and the warm water cools down a bit, Legionella and other bacteria have the opportunity to grow much more rapidly into higher amounts than under normal operating conditions,” says Janet Stout, PhD, the president of the special pathogens laboratory and a research associate professor in the department of civil and environmental engineering at the University of Pittsburgh. “Under these conditions, the bacteria are now having a party in the pipes.” The CDC itself was forced to close several buildings it leases in Atlanta when Legionella was detected in the water systems after a prolonged pandemic shutdown, CNN reported on August 7. People develop Legionnaires’ disease when they breathe in contaminated droplets of water (also known as aerosol). Symptoms are similar to those of pneumonia and COVID-19 and include cough, shortness of breath, fever, muscle aches, and headache. RELATED: Life After Lockdown: COVID-19 Safety in Offices, Restaurants, and Hair Salons
Where the Risk Is Highest
Large buildings may pose the greatest danger of Legionnaires’ disease. “Their extensive plumbing creates a great deal of surface area for biofilms to form,” says Amy Pruden, PhD, a professor of environmental and water resources engineering at Virginia Tech in Blacksburg. Biofilms are slimy layers of accumulated microorganisms, including bacteria. William Schaffner, MD, an infectious-disease specialist and a professor of preventive medicine and health policy at the Vanderbilt University School of Medicine in Nashville, Tennessee, warns that air-conditioning cooling towers, which use water and fans to cool the air inside spaces like office buildings, may be of special concern. “If the cooling towers are not well maintained, the bug can actually grow in them,” he says. “Those cooling towers create a contaminated aerosol that can spread through the air-conditioning.” When Legionella was first discovered, after an outbreak in 1976 among people who went to an American Legion convention in Philadelphia, the bacteria was traced to the hotel’s cooling tower. Hotels continue to record outbreaks: In mid-July, the Lodge at Sonoma Renaissance Resort in California reported that its water tested positive during the shutdown (it has since come back clean). Schools reopening after shutdowns are also detecting Legionella. The bacteria was recently found in four locations at Kettering Fairmont High School in Ohio after an employee was diagnosed with Legionnaires’ disease, according to WDTN News. Within a one-week period in August, the bacteria was detected at five schools in different towns in Ohio and four schools in a Pennsylvania district, The New York Times reports. RELATED: Can You Get the Coronavirus From a Public Bathroom?
How Big a Threat Is Legionnaires’ Disease?
Legionnaires’ is becoming more widespread. In the United States, the rate of reported cases of the disease has increased nearly ninefold since 2000, according to the CDC. The National Academies of Sciences, Engineering, and Medicine (NASEM) estimates that 52,000 to 70,000 Americans develop Legionnaires’ annually. Dr. Stout stresses that many people who get exposed to Legionella bacteria have little or no illness. In most cases, those who do get sick can be treated successfully with antibiotics that kill the bacteria in the body, according to the CDC. But, as with COVID-19, Legionnaires’ disease may severely affect the elderly and people who are vulnerable because of other medical issues. “It’s the people who have underlying health conditions like chronic lung disease, diabetes, and cancer, or who are organ recipients and smokers, who are at the greatest risk,” she says. “If you’re not in those risk groups, then you’re unlikely to become infected and have pneumonia.” The CDC cautions that people being treated at healthcare facilities, including long-term care facilities and hospitals, have conditions that put them at greater risk of getting sick from Legionnaires’. Some healthcare facilities that were shuttered during the COVID-19 pandemic are not reopening. “If you’re in a hospital with other problems already, and you get Legionnaires’ disease, that can be a very, very bad situation,” says Stout. The Occupational Safety and Health Administration (OSHA) estimates that the disease has a 10 percent death rate. Compare that with COVID-19, which is still being studied but has an estimated fatality rate of 1 percent or less, according to Timothy Russell, PhD, a mathematical epidemiologist at the London School of Hygiene and Tropical Medicine, commenting in the journal Nature. “The death rate for Legionnaires’ is much higher than what we’ve seen so far for COVID-19, and the complications following infection can be quite debilitating,” says Dr. Pruden, who has studied how corrosive tap water in Flint, Michigan, contributed to outbreaks of Legionnaires’ disease there. RELATED: From Nose to Toes, the List of COVID-19 Symptoms Keeps Growing
Heading Off Trouble
Building managers can take preventive measures to rid structures of harmful germs. The CDC publishes detailed plans on how to treat water systems to reduce or eliminate Legionella growth and spread, including flushing the water system, cleaning all decorative water features, such as fountains, and ensuring cooling towers are clean and well maintained. In Framingham, Massachusetts, municipal buildings including the police and fire departments, city hall, and libraries have all have been flushed out weekly since they closed in March, according to WickedLocal.com. To find out if a building is contaminated with Legionella, an owner or manager will want to start by testing the water. The Sun reported that even Buckingham Palace recently checked its royal pipes for Legionnaires’ after much of the residence was left empty in lockdown. In the United States, the aforementioned CDC guidance describes how to collect samples and send them to labs for analysis. A common cleansing approach, according to Stout, involves sending hyperchlorinated water into every fixture in a building and having it sit in the system overnight. That process, however, isn’t usually a one-and-done procedure. “[Fighting] Legionella is like whack-a-mole,” says Stout. “You knock it down, but it can come back. So you want to implement a plan where you are monitoring going forward.” Those heading back to the workplace, or to any indoor facilities, may not be sure which buildings have thoroughly disinfected their plumbing. Individuals can try to take some measures to limit exposure, but there’s only so much a person can do if contaminated water droplets are coming through the air-conditioning. Stout says people may want to use their own water bottles to avoid breathing in contaminated droplets produced by water fountains and faucets. A study published in July 2020 in the journal Emerging Infectious Diseases suggests that aerosols from flushing toilets could spread the bacteria, so people may want to close lids. “It’s believable as toilets have biofilms, just like any other plumbing or fixtures regularly in contact with drinking water, and they do generate aerosols when they are flushed,” says Pruden. She adds that many who are abiding by recommendations to prevent infection from the coronavirus may already have protection from Legionnaires’ in the form of a face covering. “I don’t know if it has been studied,” says Pruden, “but it seems logical that wearing a mask in the restroom and elsewhere in the office would reduce the possibility that you would inhale these airborne bacteria and become ill.” RELATED: Do You Really Need to Wear a Mask This Summer?
