DENVER-Lifeguards at indoor swimming pools with water spouts and sprays, waterfalls and water slides may contract a lung disease after breathing bacteria suspended in water droplets small enough to be inhaled into the lungs. This is the first time that indoor swimming pools have been identified as a source of continuously-occurring lung inflammation.
"Young, healthy, exercise-oriented lifeguards were sick," said Cecile Rose, M.D., of the Division of Environmental and Occupational Medicine at National Jewish Medical and Research Center. "If we hadn’t figured this out, people would have developed more severe lung disease."
Sixty-five percent of a group of lifeguards at an indoor pool at a large municipal recreation center complained of symptoms such as frequent cough; recurrent wheezing or chest tightness; labored, difficult breathing; and/or fever that occurred during and after work hours, according to the study published in the American Journal of Public Health.
"At indoor swimming pools with spray water features, contaminated aerosols probably place workers at greater risk than users," she said, adding, "Regular users of indoor pools with water features may be at risk, too, if they spend a great deal of time in a contaminated environment."
Lifeguards with symptoms worked an average of 31 hours a week at the pool; only people working in the pool area suffered from the illness. Airborne bacteria–suspended in water droplets sprayed from various pool water features–made the lifeguards sick even though some initially blamed their symptoms on a cold or overwork.
Called granulomatous pneumonitis, this disease is characterized by inflamed nodules in the lungs. The disease is caused by the immune system in the lungs "turning on" in reaction to an inhalant.
"The water droplets were small enough to get deep inside the lung where they stimulated an immune reaction," she said.
Although chlorine may have killed bacteria in the pool, bacteria byproducts measure in the air at the indoor pool were 27 to 162 times higher than in two control pools that didn’t have water sprays, and 25 times higher than outside air. Concentrations of airborne bacteria byproducts were highest near the lifeguard’s "crow’s nest"–about 8 feet from the surface of the pool–than at pool level. "The bacteria may have been dead, but were still capable of causing an immune reaction in the lung," Dr. Rose said.
Following treatment, the health of all the lifeguards improved, although a small number continue to require treatment for an asthma-like condition. The illness can be treated if detected early, but permanent lung scarring can occur if diagnosis and treatment aren’t timely.
"Lifeguards need to be aware that this illness is a real risk in some indoor pools," Dr. Rose said. "Once you have the disease there’s nothing you can do to protect it from worsening except permanently leave the contaminated pool area."
Dr. Rose believes "Lifeguard Lung" is not an isolated problem. "With the growth in the leisure pool industry worldwide and the use of water spray features in indoor pools," new cases of this lung disease are likely to occur, Dr. Rose writes in the article.
National Jewish Medical and Research Center is ranked as the best hospital in the United States for respiratory diseases by U.S. News & World Report, 1998.
National Jewish Medical and Research Center. December 1998.